Version: 237.4.0

* Remove full "delta" states

* Update MapGridComponentState

* abstract ComponentState

* Release notes

* Fix tests

* Fix nullable errors

* A

* Sourcegen component deltas

* Audio deltas + methids

* Also eye

* Optimise out the dictionary

* Minor fixes

* Physics deltas

* Also this

* Fix field deltas

* remove old release notes

* Make IComponentDelta implement IComponent

* add sourcegen launch settings

* make silent error loud

* Review

* UI deltas

* Slimmer

* Sourcegen bandaid

---------

Co-authored-by: ElectroJr <leonsfriedrich@gmail.com>

.github/workflows/build-docfx.yml

@@ -5,30 +5,30 @@ on:
     - cron: "0 0 * * 0"
 jobs:
   docfx:
-   runs-on: ubuntu-latest
-   steps:
-    - uses: actions/checkout@v3.6.0
-      with:
-        submodules: true
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4.2.2
+        with:
+          submodules: true
 
-    - name: Setup .NET Core
-      uses: actions/setup-dotnet@v3.2.0
-      with:
-        dotnet-version: 8.0.x
+      - name: Setup .NET Core
+        uses: actions/setup-dotnet@v4.1.0
+        with:
+          dotnet-version: 8.0.x
 
-    - name: Install dependencies
-      run: dotnet restore
+      - name: Install dependencies
+        run: dotnet restore
 
-    - name: Build Project
-      run: dotnet build --no-restore /p:WarningsAsErrors=nullable
+      - name: Build Project
+        run: dotnet build --no-restore /p:WarningsAsErrors=nullable
 
-    - name: Build DocFX
-      uses: nikeee/docfx-action@v1.0.0
-      with:
-        args: Robust.Docfx/docfx.json
+      - name: Build DocFX
+        uses: nikeee/docfx-action@v1.0.0
+        with:
+          args: Robust.Docfx/docfx.json
 
-    - name: Publish Docfx Documentation on GitHub Pages
-      uses: maxheld83/ghpages@master
-      env:
-        BUILD_DIR: Robust.Docfx/_robust-site
-        GH_PAT: ${{ secrets.GH_PAT }}
+      - name: Publish Docfx Documentation on GitHub Pages
+        uses: maxheld83/ghpages@master
+        env:
+          BUILD_DIR: Robust.Docfx/_robust-site
+          GH_PAT: ${{ secrets.GH_PAT }}

.github/workflows/build-test.yml

@@ -2,33 +2,32 @@ name: Build & Test
 
 on:
   push:
-    branches: [ master ]
+    branches: [master]
   pull_request:
-    branches: [ master ]
+    branches: [master]
 
 jobs:
   build:
     strategy:
       matrix:
-        os: [ubuntu-latest, windows-latest ] # , macos-latest] - temporarily disabled due to libfreetype.dll errors.
+        os: [ubuntu-latest, windows-latest] # , macos-latest] - temporarily disabled due to libfreetype.dll errors.
 
     runs-on: ${{ matrix.os }}
 
     steps:
-    - uses: actions/checkout@v3.6.0
-      with:
-        submodules: true
-
-    - name: Setup .NET Core
-      uses: actions/setup-dotnet@v3.2.0
-      with:
-        dotnet-version: 8.0.x
-    - name: Install dependencies
-      run: dotnet restore
-    - name: Build
-      run: dotnet build --no-restore /p:WarningsAsErrors=nullable
-    - name: Robust.UnitTesting
-      run: dotnet test --no-build Robust.UnitTesting/Robust.UnitTesting.csproj -- NUnit.ConsoleOut=0
-    - name: Robust.Analyzers.Tests
-      run: dotnet test --no-build Robust.Analyzers.Tests/Robust.Analyzers.Tests.csproj -- NUnit.ConsoleOut=0
+      - uses: actions/checkout@v4.2.2
+        with:
+          submodules: true
 
+      - name: Setup .NET Core
+        uses: actions/setup-dotnet@v4.1.0
+        with:
+          dotnet-version: 8.0.x
+      - name: Install dependencies
+        run: dotnet restore
+      - name: Build
+        run: dotnet build --no-restore /p:WarningsAsErrors=nullable
+      - name: Robust.UnitTesting
+        run: dotnet test --no-build Robust.UnitTesting/Robust.UnitTesting.csproj -- NUnit.ConsoleOut=0
+      - name: Robust.Analyzers.Tests
+        run: dotnet test --no-build Robust.Analyzers.Tests/Robust.Analyzers.Tests.csproj -- NUnit.ConsoleOut=0

.github/workflows/codeql-analysis.yml

@@ -11,14 +11,8 @@
 #
 name: "CodeQL"
 
-#on:
-#  push:
-#    branches: [ master ]
-#  pull_request:
-#    # The branches below must be a subset of the branches above
-#    branches: [ master ]
-#  schedule:
-#    - cron: '30 18 * * 6'
+on:
+  workflow_dispatch
 
 jobs:
   analyze:
@@ -28,50 +22,50 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        language: [ 'csharp' ]
+        language: ["csharp"]
         # CodeQL supports [ 'cpp', 'csharp', 'go', 'java', 'javascript', 'python' ]
         # Learn more:
         # https://docs.github.com/en/free-pro-team@latest/github/finding-security-vulnerabilities-and-errors-in-your-code/configuring-code-scanning#changing-the-languages-that-are-analyzed
 
     steps:
-    - name: Checkout repository
-      uses: actions/checkout@v3.6.0
-      with:
-        submodules: true
+      - name: Checkout repository
+        uses: actions/checkout@v4.2.2
+        with:
+          submodules: true
 
-    - name: Setup .NET Core
-      uses: actions/setup-dotnet@v3.2.0
-      with:
-        dotnet-version: 7.0.x
+      - name: Setup .NET Core
+        uses: actions/setup-dotnet@v4.1.0
+        with:
+          dotnet-version: 7.0.x
 
-    - name: Build
-      run: dotnet build
+      - name: Build
+        run: dotnet build
 
-    # Initializes the CodeQL tools for scanning.
-    - name: Initialize CodeQL
-      uses: github/codeql-action/init@v1
-      with:
-        languages: ${{ matrix.language }}
-        # If you wish to specify custom queries, you can do so here or in a config file.
-        # By default, queries listed here will override any specified in a config file.
-        # Prefix the list here with "+" to use these queries and those in the config file.
-        # queries: ./path/to/local/query, your-org/your-repo/queries@main
+      # Initializes the CodeQL tools for scanning.
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v1
+        with:
+          languages: ${{ matrix.language }}
+          # If you wish to specify custom queries, you can do so here or in a config file.
+          # By default, queries listed here will override any specified in a config file.
+          # Prefix the list here with "+" to use these queries and those in the config file.
+          # queries: ./path/to/local/query, your-org/your-repo/queries@main
 
-    # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
-    # If this step fails, then you should remove it and run the build manually (see below)
-    - name: Autobuild
-      uses: github/codeql-action/autobuild@v1
+      # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
+      # If this step fails, then you should remove it and run the build manually (see below)
+      - name: Autobuild
+        uses: github/codeql-action/autobuild@v1
 
-    # ℹ️ Command-line programs to run using the OS shell.
-    # 📚 https://git.io/JvXDl
+      # ℹ️ Command-line programs to run using the OS shell.
+      # 📚 https://git.io/JvXDl
 
-    # ✏️ If the Autobuild fails above, remove it and uncomment the following three lines
-    #    and modify them (or add more) to build your code if your project
-    #    uses a compiled language
+      # ✏️ If the Autobuild fails above, remove it and uncomment the following three lines
+      #    and modify them (or add more) to build your code if your project
+      #    uses a compiled language
 
-    #- run: |
-    #   make bootstrap
-    #   make release
+      #- run: |
+      #   make bootstrap
+      #   make release
 
-    - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v1
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v1

.github/workflows/publish-client.yml

@@ -3,51 +3,50 @@
 on:
   push:
     tags:
-    - 'v*'
+      - "v*"
 
 jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - name: Parse version
-      id: parse_version
-      shell: pwsh
-      run: |
-        $ver = [regex]::Match($env:GITHUB_REF, "refs/tags/v?(.+)").Groups[1].Value
-        echo ("::set-output name=version::{0}" -f $ver)
+      - name: Parse version
+        id: parse_version
+        shell: pwsh
+        run: |
+          $ver = [regex]::Match($env:GITHUB_REF, "refs/tags/v?(.+)").Groups[1].Value
+          echo ("::set-output name=version::{0}" -f $ver)
 
-    - uses: actions/checkout@v3.6.0
-      with:
-        submodules: true
+      - uses: actions/checkout@v4.2.2
+        with:
+          submodules: true
 
-    - name: Setup .NET Core
-      uses: actions/setup-dotnet@v3.2.0
-      with:
-        dotnet-version: 8.0.x
+      - name: Setup .NET Core
+        uses: actions/setup-dotnet@v4.1.0
+        with:
+          dotnet-version: 8.0.x
 
-    - name: Package client
-      run: Tools/package_client_build.py -p windows mac linux
+      - name: Package client
+        run: Tools/package_client_build.py -p windows mac linux
 
-    - name: Shuffle files around
-      run: |
-        mkdir "release/${{ steps.parse_version.outputs.version }}"
-        mv release/*.zip "release/${{ steps.parse_version.outputs.version }}"
+      - name: Shuffle files around
+        run: |
+          mkdir "release/${{ steps.parse_version.outputs.version }}"
+          mv release/*.zip "release/${{ steps.parse_version.outputs.version }}"
 
-    - name: Upload files to Suns
-      uses: appleboy/scp-action@master
-      with:
-        host: suns.spacestation14.com
-        username: robust-build-push
-        key: ${{ secrets.CENTCOMM_ROBUST_BUILDS_PUSH_KEY }}
-        source: "release/${{ steps.parse_version.outputs.version }}"
-        target: "/var/lib/robust-builds/builds/"
-        strip_components: 1
-
-    - name: Update manifest JSON
-      uses: appleboy/ssh-action@master
-      with:
-        host: suns.spacestation14.com
-        username: robust-build-push
-        key: ${{ secrets.CENTCOMM_ROBUST_BUILDS_PUSH_KEY }}
-        script: /home/robust-build-push/push.ps1 ${{ steps.parse_version.outputs.version }}
+      - name: Upload files to Suns
+        uses: appleboy/scp-action@master
+        with:
+          host: suns.spacestation14.com
+          username: robust-build-push
+          key: ${{ secrets.CENTCOMM_ROBUST_BUILDS_PUSH_KEY }}
+          source: "release/${{ steps.parse_version.outputs.version }}"
+          target: "/var/lib/robust-builds/builds/"
+          strip_components: 1
 
+      - name: Update manifest JSON
+        uses: appleboy/ssh-action@master
+        with:
+          host: suns.spacestation14.com
+          username: robust-build-push
+          key: ${{ secrets.CENTCOMM_ROBUST_BUILDS_PUSH_KEY }}
+          script: /home/robust-build-push/push.ps1 ${{ steps.parse_version.outputs.version }}

.github/workflows/test-content.yml

@@ -2,40 +2,39 @@ name: Test content master against engine
 
 on:
   push:
-    branches: [ master ]
+    branches: [master]
   pull_request:
-    branches: [ master ]
+    branches: [master]
 
 jobs:
   build:
-
     runs-on: ubuntu-latest
 
     steps:
-    - name: Check out content
-      uses: actions/checkout@v3.6.0
-      with:
-        repository: space-wizards/space-station-14
-        submodules: recursive
+      - name: Check out content
+        uses: actions/checkout@v4.2.2
+        with:
+          repository: space-wizards/space-station-14
+          submodules: recursive
 
-    - name: Setup .NET Core
-      uses: actions/setup-dotnet@v3.2.0
-      with:
-        dotnet-version: 8.0.x
-    - name: Disable submodule autoupdate
-      run: touch BuildChecker/DISABLE_SUBMODULE_AUTOUPDATE
+      - name: Setup .NET Core
+        uses: actions/setup-dotnet@v4.1.0
+        with:
+          dotnet-version: 8.0.x
+      - name: Disable submodule autoupdate
+        run: touch BuildChecker/DISABLE_SUBMODULE_AUTOUPDATE
 
-    - name: Check out engine version
-      run: |
-        cd RobustToolbox
-        git fetch origin ${{ github.sha }}
-        git checkout FETCH_HEAD
-        git submodule update --init --recursive
-    - name: Install dependencies
-      run: dotnet restore
-    - name: Build
-      run: dotnet build --configuration Tools --no-restore
-    - name: Content.Tests
-      run: dotnet test --no-build Content.Tests/Content.Tests.csproj -v n
-    - name: Content.IntegrationTests
-      run: COMPlus_gcServer=1 dotnet test --no-build Content.IntegrationTests/Content.IntegrationTests.csproj -v n
+      - name: Check out engine version
+        run: |
+          cd RobustToolbox
+          git fetch origin ${{ github.sha }}
+          git checkout FETCH_HEAD
+          git submodule update --init --recursive
+      - name: Install dependencies
+        run: dotnet restore
+      - name: Build
+        run: dotnet build --configuration Tools --no-restore
+      - name: Content.Tests
+        run: dotnet test --no-build Content.Tests/Content.Tests.csproj -v n
+      - name: Content.IntegrationTests
+        run: COMPlus_gcServer=1 dotnet test --no-build Content.IntegrationTests/Content.IntegrationTests.csproj -v n

MSBuild/Robust.Engine.Version.props

@@ -1,4 +1,4 @@
 <Project>
 
-    <!-- This file automatically reset by Tools/version.py -->
+    <!-- This file automatically reset by Tools/version.py -->
 

RELEASE-NOTES.md

@@ -54,6 +54,34 @@ END TEMPLATE-->
 *None yet*
 
 
+## 237.4.0
+
+### New features
+
+* Implement automatic field-level delta states via AutoGenerateComponentState via opt-in.
+
+### Bugfixes
+
+* Remove redundant TransformComponentState bool.
+
+
+## 237.3.0
+
+### New features
+
+* Added stack-like functions to `ValueList<T>` and added an `AddRange(ReadOnlySpan<T>)` overload.
+* Added new `AssetPassFilterDrop`.
+* Added a new RayCastSystem with the latest Box2D raycast + shapecasts implemented.
+
+### Bugfixes
+
+* Fixed `IPrototypeManager.TryGetKindFrom()` not working for prototypes with automatically inferred kind names.
+
+### Other
+
+* Sandbox error reference locator now works with generic method calls.
+
+
 ## 237.2.0
 
 ### Breaking changes

Robust.Client/Audio/AudioSystem.cs

@@ -504,7 +504,7 @@ public sealed partial class AudioSystem : SharedAudioSystem
         var (entity, component) = CreateAndStartPlayingStream(audioParams, stream);
         component.Global = true;
         component.Source.Global = true;
-        Dirty(entity, component);
+        DirtyField(entity, component, nameof(AudioComponent.Global));
         return (entity, component);
     }
 

Robust.Client/GameObjects/EntitySystems/ContainerSystem.cs

@@ -5,7 +5,6 @@ using Robust.Shared.GameObjects;
 using Robust.Shared.GameStates;
 using Robust.Shared.IoC;
 using Robust.Shared.Map;
-using Robust.Shared.Network;
 using Robust.Shared.Utility;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
@@ -241,7 +240,7 @@ namespace Robust.Client.GameObjects
 #if DEBUG
             var uid = GetEntity(netEntity);
 
-            if (TryComp<MetaDataComponent>(uid, out var meta))
+            if (TryComp(uid, out MetaDataComponent? meta))
             {
                 DebugTools.Assert((meta.Flags & ( MetaDataFlags.Detached | MetaDataFlags.InContainer) ) == MetaDataFlags.Detached,
                     $"Adding entity {ToPrettyString(uid)} to list of expected entities for container {container.ID} in {ToPrettyString(container.Owner)}, despite it already being in a container.");

Robust.Client/GameStates/NetGraphOverlay.cs

@@ -26,6 +26,7 @@ namespace Robust.Client.GameStates
         [Dependency] private readonly IClientNetManager _netManager = default!;
         [Dependency] private readonly IClientGameStateManager _gameStateManager = default!;
         [Dependency] private readonly IComponentFactory _componentFactory = default!;
+        [Dependency] private readonly IConsoleHost _host = default!;
         [Dependency] private readonly IEntityManager _entManager = default!;
 
         private const int HistorySize = 60 * 5; // number of ticks to keep in history.
@@ -78,7 +79,7 @@ namespace Robust.Client.GameStates
 
             string? entStateString = null;
             string? entDelString = null;
-            var conShell = IoCManager.Resolve<IConsoleHost>().LocalShell;
+            var conShell = _host.LocalShell;
 
             var entStates = args.AppliedState.EntityStates;
             if (entStates.HasContents)

Robust.Client/Graphics/Clyde/Clyde.RenderHandle.cs

@@ -362,6 +362,11 @@ namespace Robust.Client.Graphics.Clyde
                         rect.BottomLeft, rect.BottomRight, color, subRegion);
                 }
 
+                public override void DrawTexture(Texture texture, Vector2 position, Color? modulate = null)
+                {
+                    base.DrawTexture(texture, position, modulate);
+                }
+
                 /// <summary>
                 /// Draws an entity.
                 /// </summary>

Robust.Client/Graphics/Drawing/DrawingHandleBase.cs

@@ -211,6 +211,8 @@ namespace Robust.Client.Graphics
         public abstract void DrawLine(Vector2 from, Vector2 to, Color color);
 
         public abstract void RenderInRenderTarget(IRenderTarget target, Action a, Color? clearColor);
+
+        public abstract void DrawTexture(Texture texture, Vector2 position, Color? modulate = null);
     }
 
     /// <summary>

Robust.Client/Graphics/Drawing/DrawingHandleScreen.cs

@@ -92,7 +92,7 @@ namespace Robust.Client.Graphics
 
         public abstract void DrawTextureRectRegion(Texture texture, UIBox2 rect, UIBox2? subRegion = null, Color? modulate = null);
 
-        public void DrawTexture(Texture texture, Vector2 position, Color? modulate = null)
+        public override void DrawTexture(Texture texture, Vector2 position, Color? modulate = null)
         {
             CheckDisposed();
 

Robust.Client/Graphics/Drawing/DrawingHandleWorld.cs

@@ -74,7 +74,7 @@ namespace Robust.Client.Graphics
         /// <remarks>
         /// The sprite will have it's local dimensions calculated so that it has <see cref="EyeManager.PixelsPerMeter"/> texels per meter in the world.
         /// </remarks>
-        public void DrawTexture(Texture texture, Vector2 position, Color? modulate = null)
+        public override void DrawTexture(Texture texture, Vector2 position, Color? modulate = null)
         {
             CheckDisposed();
 

Robust.Client/Graphics/Font.cs

@@ -53,7 +53,7 @@ namespace Robust.Client.Graphics
         /// <param name="fallback">If the character is not available, render "<22>" instead.</param>
         /// <returns>How much to advance the cursor to draw the next character.</returns>
         public abstract float DrawChar(
-            DrawingHandleScreen handle, Rune rune, Vector2 baseline, float scale,
+            DrawingHandleBase handle, Rune rune, Vector2 baseline, float scale,
             Color color, bool fallback=true);
 
         /// <summary>
@@ -109,7 +109,7 @@ namespace Robust.Client.Graphics
         public override int GetDescent(float scale) => Handle.GetDescent(scale);
         public override int GetLineHeight(float scale) => Handle.GetLineHeight(scale);
 
-        public override float DrawChar(DrawingHandleScreen handle, Rune rune, Vector2 baseline, float scale, Color color, bool fallback=true)
+        public override float DrawChar(DrawingHandleBase handle, Rune rune, Vector2 baseline, float scale, Color color, bool fallback=true)
         {
             var metrics = Handle.GetCharMetrics(rune, scale);
             if (!metrics.HasValue)
@@ -132,7 +132,10 @@ namespace Robust.Client.Graphics
             }
 
             baseline += new Vector2(metrics.Value.BearingX, -metrics.Value.BearingY);
-            handle.DrawTexture(texture, baseline, color);
+            if(handle is DrawingHandleWorld worldhandle)
+                worldhandle.DrawTextureRect(texture,  Box2.FromDimensions(baseline, texture.Size));
+            else
+                handle.DrawTexture(texture, baseline, color);
             return metrics.Value.Advance;
         }
 
@@ -169,7 +172,7 @@ namespace Robust.Client.Graphics
         public override int GetLineHeight(float scale) => _main.GetLineHeight(scale);
 
         // DrawChar just proxies to the stack, or invokes _main's fallback.
-        public override float DrawChar(DrawingHandleScreen handle, Rune rune, Vector2 baseline, float scale, Color color, bool fallback=true)
+        public override float DrawChar(DrawingHandleBase handle, Rune rune, Vector2 baseline, float scale, Color color, bool fallback=true)
         {
             foreach (var f in Stack)
             {
@@ -207,7 +210,7 @@ namespace Robust.Client.Graphics
         public override int GetDescent(float scale) => default;
         public override int GetLineHeight(float scale) => default;
 
-        public override float DrawChar(DrawingHandleScreen handle, Rune rune, Vector2 baseline, float scale, Color color, bool fallback=true)
+        public override float DrawChar(DrawingHandleBase handle, Rune rune, Vector2 baseline, float scale, Color color, bool fallback=true)
         {
             // Nada, it's a dummy after all.
             return 0;

Robust.Client/Physics/GridFixtureSystem.cs

@@ -13,8 +13,9 @@ namespace Robust.Client.Physics
     internal sealed class GridFixtureSystem : SharedGridFixtureSystem
     {
         [Dependency] private readonly IOverlayManager _overlay = default!;
-        [Dependency] private readonly IMapManager _map = default!;
+        [Dependency] private readonly IMapManager _mapManager = default!;
         [Dependency] private readonly SharedTransformSystem _transform = default!;
+        [Dependency] private readonly SharedMapSystem _map = default!;
 
         public bool EnableDebug
         {
@@ -28,7 +29,7 @@ namespace Robust.Client.Physics
 
                 if (_enableDebug)
                 {
-                    var overlay = new GridSplitNodeOverlay(_map, this, _transform);
+                    var overlay = new GridSplitNodeOverlay(_mapManager, this, _transform, _map);
                     _overlay.AddOverlay(overlay);
                     RaiseNetworkEvent(new RequestGridNodesMessage());
                 }
@@ -74,12 +75,14 @@ namespace Robust.Client.Physics
             private readonly IMapManager _mapManager;
             private readonly GridFixtureSystem _system;
             private readonly SharedTransformSystem _transform;
+            private readonly SharedMapSystem _map;
 
-            public GridSplitNodeOverlay(IMapManager mapManager, GridFixtureSystem system, SharedTransformSystem transform)
+            public GridSplitNodeOverlay(IMapManager mapManager, GridFixtureSystem system, SharedTransformSystem transform, SharedMapSystem map)
             {
                 _mapManager = mapManager;
                 _system = system;
                 _transform = transform;
+                _map = map;
             }
 
             protected internal override void Draw(in OverlayDrawArgs args)
@@ -89,7 +92,7 @@ namespace Robust.Client.Physics
                 var state = (_system, _transform, args.WorldBounds, worldHandle);
 
                 _mapManager.FindGridsIntersecting(args.MapId, args.WorldBounds, ref state,
-                    static (EntityUid uid, MapGridComponent grid,
+                    (EntityUid uid, MapGridComponent grid,
                         ref (GridFixtureSystem system, SharedTransformSystem transform, Box2Rotated worldBounds, DrawingHandleWorld worldHandle) tuple) =>
                     {
                         // May not have received nodes yet.
@@ -97,7 +100,7 @@ namespace Robust.Client.Physics
                             return true;
 
                         tuple.worldHandle.SetTransform(tuple.transform.GetWorldMatrix(uid));
-                        var chunkEnumerator = grid.GetMapChunks(tuple.worldBounds);
+                        var chunkEnumerator = _map.GetMapChunks(uid, grid, tuple.worldBounds);
 
                         while (chunkEnumerator.MoveNext(out var chunk))
                         {

Robust.Client/Placement/Modes/AlignSnapgridCenter.cs

@@ -25,7 +25,9 @@ namespace Robust.Client.Placement.Modes
             {
                 var viewportSize = (Vector2)pManager.Clyde.ScreenSize;
 
-                var gridPosition = Grid.MapToGrid(pManager.EyeManager.ScreenToMap(Vector2.Zero));
+                var gridUid = pManager.EntityManager.System<SharedTransformSystem>().GetGrid(MouseCoords);
+
+                var gridPosition = pManager.EntityManager.System<SharedMapSystem>().MapToGrid(gridUid!.Value, pManager.EyeManager.ScreenToMap(Vector2.Zero));
 
                 var gridstart = pManager.EyeManager.CoordinatesToScreen(
                     gridPosition.WithPosition(new Vector2(MathF.Floor(gridPosition.X), MathF.Floor(gridPosition.Y))));
@@ -52,9 +54,9 @@ namespace Robust.Client.Placement.Modes
         {
             MouseCoords = ScreenToCursorGrid(mouseScreen);
 
-            var gridIdOpt = MouseCoords.GetGridUid(pManager.EntityManager);
+            var gridIdOpt = pManager.EntityManager.System<SharedTransformSystem>().GetGrid(MouseCoords);
             SnapSize = 1f;
-            if (gridIdOpt is EntityUid gridId && gridId.IsValid())
+            if (gridIdOpt is { } gridId && gridId.IsValid())
             {
                 Grid = pManager.EntityManager.GetComponent<MapGridComponent>(gridId);
                 SnapSize = Grid.TileSize; //Find snap size for the grid.

Robust.Client/Placement/PlacementManager.cs

@@ -27,6 +27,7 @@ namespace Robust.Client.Placement
 {
     public sealed partial class PlacementManager : IPlacementManager, IDisposable, IEntityEventSubscriber
     {
+        [Dependency] private readonly ILogManager _logManager = default!;
         [Dependency] private readonly IClientNetManager _networkManager = default!;
         [Dependency] internal readonly IPlayerManager PlayerManager = default!;
         [Dependency] internal readonly IResourceCache ResourceCache = default!;
@@ -42,6 +43,11 @@ namespace Robust.Client.Placement
         [Dependency] private readonly IOverlayManager _overlayManager = default!;
         [Dependency] internal readonly IClyde Clyde = default!;
 
+        private ISawmill _sawmill = default!;
+
+        private SharedMapSystem Maps => EntityManager.System<SharedMapSystem>();
+        private SharedTransformSystem XformSystem => EntityManager.System<SharedTransformSystem>();
+
         /// <summary>
         ///     How long before a pending tile change is dropped.
         /// </summary>
@@ -188,6 +194,7 @@ namespace Robust.Client.Placement
         public void Initialize()
         {
             _drawingShader = _prototypeManager.Index<ShaderPrototype>("unshaded").Instance();
+            _sawmill = _logManager.GetSawmill("placement");
 
             _networkManager.RegisterNetMessage<MsgPlacement>(HandlePlacementMessage);
 
@@ -337,7 +344,11 @@ namespace Robust.Client.Placement
 
         private void HandleTileChanged(ref TileChangedEvent args)
         {
-            var coords = EntityManager.GetComponent<MapGridComponent>(args.NewTile.GridUid).GridTileToLocal(args.NewTile.GridIndices);
+            var coords = Maps.GridTileToLocal(
+                args.NewTile.GridUid,
+                EntityManager.GetComponent<MapGridComponent>(args.NewTile.GridUid),
+                args.NewTile.GridIndices);
+
             _pendingTileChanges.RemoveAll(c => c.Item1 == coords);
         }
 
@@ -475,7 +486,7 @@ namespace Robust.Client.Placement
 
             if (!_modeDictionary.TryFirstOrNull(pair => pair.Key.Equals(CurrentPermission.PlacementOption), out KeyValuePair<string, Type>? placeMode))
             {
-                Logger.LogS(LogLevel.Warning, nameof(PlacementManager), $"Invalid placement mode `{CurrentPermission.PlacementOption}`");
+                _sawmill.Log(LogLevel.Warning, $"Invalid placement mode `{CurrentPermission.PlacementOption}`");
                 Clear();
                 return;
             }
@@ -531,8 +542,7 @@ namespace Robust.Client.Placement
                     coordinates = new EntityCoordinates();
                     return false;
                 }
-                coordinates = EntityCoordinates.FromMap(MapManager,
-                                                        EyeManager.PixelToMap(InputManager.MouseScreenPosition));
+                coordinates = XformSystem.ToCoordinates(ent, EyeManager.PixelToMap(InputManager.MouseScreenPosition));
                 return true;
             }
         }
@@ -648,7 +658,7 @@ namespace Robust.Client.Placement
                 PlayerManager.LocalEntity is not {Valid: true} controlled)
                 return;
 
-            var worldPos = EntityManager.GetComponent<TransformComponent>(controlled).WorldPosition;
+            var worldPos = XformSystem.GetWorldPosition(controlled);
 
             args.WorldHandle.DrawCircle(worldPos, CurrentPermission.Range, new Color(1, 1, 1, 0.25f));
         }
@@ -754,14 +764,14 @@ namespace Robust.Client.Placement
 
             if (CurrentPermission.IsTile)
             {
-                var gridIdOpt = EntityManager.System<SharedTransformSystem>().GetGrid(coordinates);
+                var gridIdOpt = XformSystem.GetGrid(coordinates);
                 // If we have actually placed something on a valid grid...
                 if (gridIdOpt is { } gridId && gridId.IsValid())
                 {
                     var grid = EntityManager.GetComponent<MapGridComponent>(gridId);
 
                     // no point changing the tile to the same thing.
-                    if (EntityManager.System<SharedMapSystem>().GetTileRef(gridId, grid, coordinates).Tile.TypeId == CurrentPermission.TileType)
+                    if (Maps.GetTileRef(gridId, grid, coordinates).Tile.TypeId == CurrentPermission.TileType)
                         return;
                 }
 

Robust.Client/ResourceManagement/ResourceCache.Preload.cs

@@ -143,9 +143,9 @@ namespace Robust.Client.ResourceManagement
                 }
             });
 
-            // Do not meta-atlas RSIs with custom load parameters.
-            var atlasList = rsiList.Where(x => x.LoadParameters == TextureLoadParameters.Default).ToArray();
-            var nonAtlasList = rsiList.Where(x => x.LoadParameters != TextureLoadParameters.Default).ToArray();
+            var atlasLookup = rsiList.ToLookup(ShouldMetaAtlas);
+            var atlasList = atlasLookup[true].ToArray();
+            var nonAtlasList = atlasLookup[false].ToArray();
 
             foreach (var data in nonAtlasList)
             {
@@ -225,8 +225,9 @@ namespace Robust.Client.ResourceManagement
 
             void FinalizeMetaAtlas(int toIndex, Image<Rgba32> sheet)
             {
-                var atlas = Clyde.LoadTextureFromImage(sheet);
-                for (int i = finalized + 1; i <= toIndex; i++)
+                var fromIndex = finalized + 1;
+                var atlas = Clyde.LoadTextureFromImage(sheet, $"Meta atlas {fromIndex}-{toIndex}");
+                for (int i = fromIndex; i <= toIndex; i++)
                 {
                     var rsi = atlasList[i];
                     rsi.AtlasTexture = atlas;
@@ -282,7 +283,11 @@ namespace Robust.Client.ResourceManagement
                 nonAtlasList.Length,
                 errors,
                 sw.Elapsed);
+        }
 
+        private static bool ShouldMetaAtlas(RSIResource.LoadStepData rsi)
+        {
+            return rsi.MetaAtlas && rsi.LoadParameters == TextureLoadParameters.Default;
         }
     }
 }

Robust.Client/ResourceManagement/ResourceTypes/RSIResource.cs

@@ -183,6 +183,7 @@ namespace Robust.Client.ResourceManagement
             data.DimX = dimensionX;
             data.CallbackOffsets = callbackOffsets;
             data.LoadParameters = metadata.LoadParameters;
+            data.MetaAtlas = metadata.MetaAtlas;
         }
 
         internal static void LoadPostTexture(LoadStepData data)
@@ -386,6 +387,7 @@ namespace Robust.Client.ResourceManagement
             public Vector2i AtlasOffset;
             public RSI Rsi = default!;
             public TextureLoadParameters LoadParameters;
+            public bool MetaAtlas;
         }
 
         internal struct StateReg

Robust.Client/UserInterface/Controls/ColorSelectorSliders.cs

@@ -1,8 +1,5 @@
 using System;
 using System.Collections.Generic;
-using Robust.Client.Graphics;
-using Robust.Client.ResourceManagement;
-using Robust.Shared.IoC;
 using Robust.Shared.Localization;
 using Robust.Shared.Maths;
 
@@ -89,8 +86,6 @@ public sealed class ColorSelectorSliders : Control
     private OptionButton _typeSelector;
     private List<ColorSelectorType> _types = new();
 
-    private static ShaderInstance _shader = default!;
-
     private ColorSelectorStyleBox _topStyle;
     private ColorSelectorStyleBox _middleStyle;
     private ColorSelectorStyleBox _bottomStyle;

Robust.Client/UserInterface/Controls/GridContainer.cs

@@ -302,7 +302,6 @@ namespace Robust.Client.UserInterface.Controls
             {
                 if (!child.Visible)
                 {
-                    index--;
                     continue;
                 }
 

Robust.Client/UserInterface/RichTextEntry.cs

@@ -176,7 +176,7 @@ namespace Robust.Client.UserInterface
 
         public readonly void Draw(
             MarkupTagManager tagManager,
-            DrawingHandleScreen handle,
+            DrawingHandleBase handle,
             Font defaultFont,
             UIBox2 drawBox,
             float verticalOffset,

Robust.Packaging/AssetProcessing/Passes/AssetPassFilterDrop.cs

@@ -0,0 +1,18 @@
+namespace Robust.Packaging.AssetProcessing.Passes;
+
+/// <summary>
+/// Asset pass that drops all files that match a predicate. Files that do not match are ignored.
+/// </summary>
+public sealed class AssetPassFilterDrop(Func<AssetFile, bool> predicate) : AssetPass
+{
+    public Func<AssetFile, bool> Predicate { get; } = predicate;
+
+    protected override AssetFileAcceptResult AcceptFile(AssetFile file)
+    {
+        // Just do nothing with the file so it gets discarded.
+        if (Predicate(file))
+            return AssetFileAcceptResult.Consumed;
+
+        return base.AcceptFile(file);
+    }
+}

Robust.Serialization.Generator/Generator.cs

@@ -1,4 +1,5 @@
-using System.Text;
+using System.Diagnostics.CodeAnalysis;
+using System.Text;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
@@ -13,6 +14,8 @@ public class Generator : IIncrementalGenerator
     private const string TypeCopierInterfaceNamespace = "Robust.Shared.Serialization.TypeSerializers.Interfaces.ITypeCopier";
     private const string TypeCopyCreatorInterfaceNamespace = "Robust.Shared.Serialization.TypeSerializers.Interfaces.ITypeCopyCreator";
     private const string SerializationHooksNamespace = "Robust.Shared.Serialization.ISerializationHooks";
+    private const string AutoStateAttributeName = "Robust.Shared.Analyzers.AutoGenerateComponentStateAttribute";
+    private const string ComponentDeltaInterfaceName = "Robust.Shared.GameObjects.IComponentDelta";
 
     public void Initialize(IncrementalGeneratorInitializationContext initContext)
     {
@@ -35,6 +38,7 @@ public class Generator : IIncrementalGenerator
                 var builder = new StringBuilder();
                 var containingTypes = new Stack<INamedTypeSymbol>();
                 var declarationsGenerated = new HashSet<string>();
+                var deltaType = compilation.GetTypeByMetadataName(ComponentDeltaInterfaceName)!;
 
                 foreach (var declaration in declarations)
                 {
@@ -106,9 +110,9 @@ using Robust.Shared.Serialization.TypeSerializers.Interfaces;
 {
     {{GetConstructor(definition)}}
 
-    {{GetCopyMethods(definition)}}
+    {{GetCopyMethods(definition, deltaType)}}
 
-    {{GetInstantiators(definition)}}
+    {{GetInstantiators(definition, deltaType)}}
 }
 
 {{containingTypesEnd}}
@@ -192,7 +196,7 @@ using Robust.Shared.Serialization.TypeSerializers.Interfaces;
          return builder.ToString();
      }
 
-    private static string GetCopyMethods(DataDefinition definition)
+    private static string GetCopyMethods(DataDefinition definition, ITypeSymbol deltaType)
     {
         var builder = new StringBuilder();
 
@@ -263,7 +267,7 @@ using Robust.Shared.Serialization.TypeSerializers.Interfaces;
                              {{baseCopy}}
                              """);
 
-        foreach (var @interface in GetImplicitDataDefinitionInterfaces(definition.Type, true))
+        foreach (var @interface in InternalGetImplicitDataDefinitionInterfaces(definition.Type, true, deltaType))
         {
             var interfaceModifiers = baseType != null && baseType.AllInterfaces.Contains(@interface, SymbolEqualityComparer.Default)
                 ? "override "
@@ -292,7 +296,7 @@ using Robust.Shared.Serialization.TypeSerializers.Interfaces;
         return builder.ToString();
     }
 
-    private static string GetInstantiators(DataDefinition definition)
+    private static string GetInstantiators(DataDefinition definition, ITypeSymbol deltaType)
     {
         var builder = new StringBuilder();
         var modifiers = string.Empty;
@@ -326,7 +330,7 @@ using Robust.Shared.Serialization.TypeSerializers.Interfaces;
                                  """);
         }
 
-        foreach (var @interface in GetImplicitDataDefinitionInterfaces(definition.Type, false))
+        foreach (var @interface in InternalGetImplicitDataDefinitionInterfaces(definition.Type, false, deltaType))
         {
             var interfaceName = @interface.ToDisplayString();
             builder.AppendLine($$"""
@@ -345,6 +349,31 @@ using Robust.Shared.Serialization.TypeSerializers.Interfaces;
         return builder.ToString();
     }
 
+    [SuppressMessage("ReSharper", "PossibleMultipleEnumeration")]
+    private static IEnumerable<ITypeSymbol> InternalGetImplicitDataDefinitionInterfaces(ITypeSymbol type, bool all, ITypeSymbol deltaType)
+    {
+        var symbols = GetImplicitDataDefinitionInterfaces(type, all);
+
+        // TODO SOURCE GEN
+        // fix this jank
+        // The comp-state source generator will add an "IComponentDelta" interface to classes with the auto state
+        // attribute, and this generator creates methods that those classes then have to implement because
+        // IComponentDelta a DataDefinition via the ImplicitDataDefinitionForInheritorsAttribute on IComponent.
+        if (!TryGetAttribute(type, AutoStateAttributeName, out var data))
+            return symbols;
+
+        // If it doesn't have field deltas then ignore
+        if (data.ConstructorArguments[1] is not { Value: bool fields and true })
+        {
+            return symbols;
+        }
+
+        if (symbols.Any(x => x.ToDisplayString() == deltaType.ToDisplayString()))
+            return symbols;
+
+        return symbols.Append(deltaType);
+    }
+
     // TODO serveronly? do we care? who knows!!
     private static StringBuilder CopyDataFields(DataDefinition definition)
     {

Robust.Serialization.Generator/Types.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
@@ -302,6 +303,21 @@ internal static class Types
         return false;
     }
 
+    internal static bool TryGetAttribute(ISymbol symbol, string attributeName, [NotNullWhen(true)] out AttributeData? data)
+    {
+        foreach (var attribute in symbol.GetAttributes())
+        {
+            if (attribute.AttributeClass?.ToDisplayString() == attributeName)
+            {
+                data = attribute;
+                return true;
+            }
+        }
+
+        data = null;
+        return false;
+    }
+
     internal static IEnumerable<ITypeSymbol> GetBaseTypes(ITypeSymbol type)
     {
         var baseType = type.BaseType;

Robust.Server/BaseServer.cs

@@ -223,10 +223,10 @@ namespace Robust.Server
 
                 if (!Path.IsPathRooted(fullPath))
                 {
-                    logPath = PathHelpers.ExecutableRelativeFile(fullPath);
+                    fullPath = PathHelpers.ExecutableRelativeFile(fullPath);
                 }
 
-                logHandler = new FileLogHandler(logPath);
+                logHandler = new FileLogHandler(fullPath);
             }
 
             _log.RootSawmill.Level = _config.GetCVar(CVars.LogLevel);

Robust.Server/Placement/PlacementManager.cs

@@ -143,7 +143,7 @@ namespace Robust.Server.Placement
                         _factory.GetComponentName(typeof(PlacementReplacementComponent)), out var compRegistry))
                 {
                     var key = ((PlacementReplacementComponent)compRegistry.Component).Key;
-                    var gridUid = coordinates.GetGridUid(_entityManager);
+                    var gridUid = _xformSystem.GetGrid(coordinates);
 
                     if (_entityManager.TryGetComponent<MapGridComponent>(gridUid, out var grid))
                     {
@@ -191,7 +191,7 @@ namespace Robust.Server.Placement
 
             EntityUid gridId = coordinates.EntityId;
             if (_entityManager.TryGetComponent(coordinates.EntityId, out grid)
-                || _mapManager.TryFindGridAt(coordinates.ToMap(_entityManager, _xformSystem), out gridId, out grid))
+                || _mapManager.TryFindGridAt(_xformSystem.ToMapCoordinates(coordinates), out gridId, out grid))
             {
                 _maps.SetTile(gridId, grid, coordinates, new Tile(tileType));
 
@@ -200,10 +200,13 @@ namespace Robust.Server.Placement
             }
             else if (tileType != 0) // create a new grid
             {
-                var newGrid = _mapManager.CreateGridEntity(coordinates.GetMapId(_entityManager));
-                var newGridXform = _entityManager.GetComponent<TransformComponent>(newGrid);
+                var newGrid = _mapManager.CreateGridEntity(_xformSystem.GetMapId(coordinates));
+                var newGridXform = new Entity<TransformComponent>(
+                    newGrid.Owner,
+                    _entityManager.GetComponent<TransformComponent>(newGrid));
+
                 _xformSystem.SetWorldPosition(newGridXform, coordinates.Position - newGrid.Comp.TileSizeHalfVector); // assume bottom left tile origin
-                var tilePos = newGrid.Comp.WorldToTile(coordinates.Position);
+                var tilePos = _maps.WorldToTile(newGrid.Owner, newGrid.Comp, coordinates.Position);
                 _maps.SetTile(newGrid.Owner, newGrid.Comp, tilePos, new Tile(tileType));
 
                 var placementEraseEvent = new PlacementTileEvent(tileType, coordinates, placingUserId);
@@ -228,7 +231,7 @@ namespace Robust.Server.Placement
         {
             EntityCoordinates start = _entityManager.GetCoordinates(msg.NetCoordinates);
             Vector2 rectSize = msg.RectSize;
-            foreach (var entity in _lookup.GetEntitiesIntersecting(start.GetMapId(_entityManager),
+            foreach (var entity in _lookup.GetEntitiesIntersecting(_xformSystem.GetMapId(start),
                 new Box2(start.Position, start.Position + rectSize)))
             {
                 if (_entityManager.Deleted(entity) ||

Robust.Server/ServerStatus/StatusHost.Acz.Sources.cs

@@ -24,7 +24,6 @@ namespace Robust.Server.ServerStatus;
 
 internal sealed partial class StatusHost
 {
-    private (string binFolder, string[] assemblies)? _aczInfo;
     private IMagicAczProvider? _magicAczProvider;
     private IFullHybridAczProvider? _fullHybridAczProvider;
 
@@ -158,8 +157,7 @@ internal sealed partial class StatusHost
         {
             _aczSawmill.Verbose("Using default magic ACZ provider");
             // Default provider
-            var (binFolderPath, assemblyNames) =
-                _aczInfo ?? ("Content.Client", new[] { "Content.Client", "Content.Shared" });
+            var (binFolderPath, assemblyNames) = ("Content.Client", new[] { "Content.Client", "Content.Shared" });
 
             var info = new DefaultMagicAczInfo(binFolderPath, assemblyNames);
             provider = new DefaultMagicAczProvider(info, _deps);

Robust.Server/ServerStatus/StatusHost.Handlers.cs

@@ -103,6 +103,22 @@ namespace Robust.Server.ServerStatus
                 ["desc"] = _serverDescCache,
             };
 
+            var privacyPolicyLink = _cfg.GetCVar(CVars.StatusPrivacyPolicyLink);
+            var privacyPolicyIdentifier = _cfg.GetCVar(CVars.StatusPrivacyPolicyIdentifier);
+            var privacyPolicyVersion = _cfg.GetCVar(CVars.StatusPrivacyPolicyVersion);
+
+            if (!string.IsNullOrEmpty(privacyPolicyLink)
+                && !string.IsNullOrEmpty(privacyPolicyIdentifier)
+                && !string.IsNullOrEmpty(privacyPolicyVersion))
+            {
+                jObject["privacy_policy"] = new JsonObject
+                {
+                    ["identifier"] = privacyPolicyIdentifier,
+                    ["version"] = privacyPolicyVersion,
+                    ["link"] = privacyPolicyLink,
+                };
+            }
+
             OnInfoRequest?.Invoke(jObject);
 
             await context.RespondJsonAsync(jObject);

Robust.Shared.CompNetworkGenerator/ComponentNetworkGenerator.cs

@@ -36,7 +36,9 @@ namespace Robust.Shared.CompNetworkGenerator
         private static readonly SymbolDisplayFormat FullNullableFormat =
             FullyQualifiedFormat.WithMiscellaneousOptions(IncludeNullableReferenceTypeModifier);
 
-        private static string? GenerateSource(in GeneratorExecutionContext context, INamedTypeSymbol classSymbol, CSharpCompilation comp, bool raiseAfterAutoHandle)
+        private static string? GenerateSource(in GeneratorExecutionContext context, INamedTypeSymbol classSymbol, CSharpCompilation comp,
+            bool raiseAfterAutoHandle,
+            bool fieldDeltas)
         {
             var nameSpace = classSymbol.ContainingNamespace.ToDisplayString();
             var componentName = classSymbol.Name;
@@ -134,54 +136,154 @@ namespace Robust.Shared.CompNetworkGenerator
             //            component.Count = state.Count;
             var handleStateSetters = new StringBuilder();
 
+            // Builds the string for copying delta fields in IComponentDelta to a new full state.
+            var deltaCreate = new StringBuilder();
+
+            // Delta field states
+            var deltaGetFields = new StringBuilder();
+
+            var deltaHandleFields = new StringBuilder();
+
+            // Apply the delta field to the full state.
+            var deltaApply = new List<string>();
+
+            var index = -1;
+
+            var fieldsStr = new StringBuilder();
+            var fieldStates = new StringBuilder();
+
+            var networkedTypes = new List<string>();
+
             foreach (var (type, name) in fields)
             {
+                index++;
+
+                if (index == 0)
+                {
+                    fieldsStr.Append(@$"""{name}""");
+                }
+                else
+                {
+                    fieldsStr.Append(@$", ""{name}""");
+                }
+
                 var typeDisplayStr = type.ToDisplayString(FullNullableFormat);
                 var nullable = type.NullableAnnotation == NullableAnnotation.Annotated;
                 var nullableAnnotation = nullable ? "?" : string.Empty;
 
+                string deltaStateName = $"{name}_FieldComponentState";
+
+                // The type used for networking, e.g. EntityUid -> NetEntity
+                string networkedType;
+
+                string getField;
+                string? cast;
+                // TODO: Uhh I just need casts or something.
+                var castString = typeDisplayStr.Substring(8);
+
+                deltaGetFields.Append(@$"
+                    case {Math.Pow(2, index)}:
+                        args.State = new {deltaStateName}()
+                        {{
+                        ");
+
+                deltaHandleFields.Append(@$"
+                case {deltaStateName} {deltaStateName}_State:
+                {{
+");
+
+                var fieldHandleValue = $"{deltaStateName}_State.{name}!";
+
                 switch (typeDisplayStr)
                 {
                     case GlobalEntityUidName:
                     case GlobalNullableEntityUidName:
-                        stateFields.Append($@"
-        public NetEntity{nullableAnnotation} {name} = default!;");
+                        networkedType = $"NetEntity{nullableAnnotation}";
+
+                        stateFields.Append($@"
+        public {networkedType} {name} = default!;");
+
+                        getField = $"GetNetEntity(component.{name})";
+                        cast = $"(NetEntity{nullableAnnotation})";
 
-                        getStateInit.Append($@"
-                {name} = GetNetEntity(component.{name}),");
                         handleStateSetters.Append($@"
-            component.{name} = EnsureEntity<{componentName}>(state.{name}, uid);");
+        component.{name} = EnsureEntity<{componentName}>(state.{name}, uid);");
+
+                        deltaHandleFields.Append($@"
+                component.{name} = EnsureEntity<{componentName}>({cast} {fieldHandleValue}, uid);");
+
+                        deltaCreate.Append($@"
+            {name} = fullState.{name},");
+
+                        deltaApply.Add($@"
+                    fullState.{name} = {name};");
 
                         break;
                     case GlobalEntityCoordinatesName:
                     case GlobalNullableEntityCoordinatesName:
-                        stateFields.Append($@"
-        public NetCoordinates{nullableAnnotation} {name} = default!;");
+                        networkedType = $"NetCoordinates{nullableAnnotation}";
+
+                        stateFields.Append($@"
+        public {networkedType} {name} = default!;");
+
+                        getField = $"GetNetCoordinates(component.{name})";
+                        cast = $"(NetCoordinates{nullableAnnotation})";
 
-                        getStateInit.Append($@"
-                {name} = GetNetCoordinates(component.{name}),");
                         handleStateSetters.Append($@"
-            component.{name} = EnsureCoordinates<{componentName}>(state.{name}, uid);");
+        component.{name} = EnsureCoordinates<{componentName}>(state.{name}, uid);");
+
+                        deltaHandleFields.Append($@"
+                component.{name} = EnsureCoordinates<{componentName}>({cast} {fieldHandleValue}, uid);");
+
+                        deltaCreate.Append($@"
+            {name} = fullState.{name},");
+
+                        deltaApply.Add($@"
+                    fullState.{name} = {name};");
 
                         break;
                     case GlobalEntityUidSetName:
-                        stateFields.Append($@"
-        public {GlobalNetEntityUidSetName} {name} = default!;");
+                        networkedType = $"{GlobalNetEntityUidSetName}";
+
+                        stateFields.Append($@"
+        public {networkedType} {name} = default!;");
+
+                        getField = $"GetNetEntitySet(component.{name})";
+                        cast = $"({GlobalNetEntityUidSetName})";
 
-                        getStateInit.Append($@"
-                {name} = GetNetEntitySet(component.{name}),");
                         handleStateSetters.Append($@"
-            EnsureEntitySet<{componentName}>(state.{name}, uid, component.{name});");
+        EnsureEntitySet<{componentName}>(state.{name}, uid, component.{name});");
+
+                        deltaHandleFields.Append($@"
+                EnsureEntitySet<{componentName}>({cast} {fieldHandleValue}, uid, component.{name});");
+
+                        deltaCreate.Append($@"
+            {name} = new(fullState.{name}),");
+
+                        deltaApply.Add($@"
+                    fullState.{name} = {name};");
 
                         break;
                     case GlobalEntityUidListName:
-                        stateFields.Append($@"
-        public {GlobalNetEntityUidListName} {name} = default!;");
+                        networkedType = $"{GlobalNetEntityUidListName}";
+
+                        stateFields.Append($@"
+                        public {networkedType} {name} = default!;");
+
+                        getField = $"GetNetEntityList(component.{name})";
+                        cast = $"({GlobalNetEntityUidListName})";
 
-                        getStateInit.Append($@"
-                {name} = GetNetEntityList(component.{name}),");
                         handleStateSetters.Append($@"
-            EnsureEntityList<{componentName}>(state.{name}, uid, component.{name});");
+        EnsureEntityList<{componentName}>(state.{name}, uid, component.{name});");
+
+                        deltaHandleFields.Append($@"
+                EnsureEntityList<{componentName}>({cast} {fieldHandleValue}, uid, component.{name});");
+
+                        deltaCreate.Append($@"
+            {name} = new(fullState.{name}),");
+
+                        deltaApply.Add($@"
+                    fullState.{name} = {name};");
 
                         break;
                     default:
@@ -205,69 +307,150 @@ namespace Robust.Shared.CompNetworkGenerator
                                     ensureGeneric = componentName;
                                 }
 
-                                stateFields.Append($@"
-        public Dictionary<{key}, {value}> {name} = default!;");
+                                networkedType = $"Dictionary<{key}, {value}>";
 
-                                getStateInit.Append($@"
-                {name} = GetNetEntityDictionary(component.{name}),");
+                                stateFields.Append($@"
+        public {networkedType} {name} = default!;");
+
+                                getField = $"GetNetEntityDictionary(component.{name})";
 
                                 if (valueNullable && value is not GlobalNetEntityName and not GlobalNetEntityNullableName)
                                 {
+                                    cast = $"(Dictionary<{key}, {value}>)";
+
                                     handleStateSetters.Append($@"
-            EnsureEntityDictionaryNullableValue<{componentName}, {value}>(state.{name}, uid, component.{name});");
+                    EnsureEntityDictionaryNullableValue<{componentName}, {value}>(state.{name}, uid, component.{name});");
+
+                                    deltaHandleFields.Append($@"
+                            EnsureEntityDictionaryNullableValue<{componentName}, {value}>({cast} {fieldHandleValue}, uid, component.{name});");
                                 }
                                 else
                                 {
+                                    cast = $"({castString})";
+
                                     handleStateSetters.Append($@"
-            EnsureEntityDictionary<{ensureGeneric}>(state.{name}, uid, component.{name});");
+                    EnsureEntityDictionary<{ensureGeneric}>(state.{name}, uid, component.{name})");
+
+                                    deltaHandleFields.Append($@"
+                            EnsureEntityDictionary<{ensureGeneric}>({cast} {fieldHandleValue}, uid, component.{name});");
                                 }
 
+                                deltaCreate.Append($@"
+                {name} = new(fullState.{name}),");
+
+                                deltaApply.Add($@"
+                    fullState.{name} = {name};");
+
                                 break;
                             }
 
                             if (value is GlobalEntityUidName or GlobalNullableEntityUidName)
                             {
+                                networkedType = $"Dictionary<{key}, {value}>";
                                 value = valueNullable ? GlobalNetEntityNullableName : GlobalNetEntityName;
 
                                 stateFields.Append($@"
-        public Dictionary<{key}, {value}> {name} = default!;");
+        public {networkedType} {name} = default!;");
+
+                                getField = $"GetNetEntityDictionary(component.{name})";
+                                cast = $"(Dictionary<{key}, {value}>)";
 
-                                getStateInit.Append($@"
-                {name} = GetNetEntityDictionary(component.{name}),");
                                 handleStateSetters.Append($@"
-            EnsureEntityDictionary<{componentName}, {key}>(state.{name}, uid, component.{name});");
+                EnsureEntityDictionary<{componentName}, {key}>(state.{name}, uid, component.{name});");
+
+                                deltaHandleFields.Append($@"
+                        EnsureEntityDictionary<{componentName}, {key}>({cast} {fieldHandleValue}, uid, component.{name});");
+
+                                deltaCreate.Append($@"
+                {name} = new(fullState.{name}),");
+
+                                deltaApply.Add($@"
+                    fullState.{name} = {name};");
 
                                 break;
                             }
                         }
 
+                        networkedType = $"{typeDisplayStr}";
+
                         stateFields.Append($@"
-        public {typeDisplayStr} {name} = default!;");
+        public {networkedType} {name} = default!;");
 
                         if (IsCloneType(type))
                         {
-                            // get first ctor arg of the field attribute, which determines whether the field should be cloned
-                            // (like if its a dict or list)
-                            getStateInit.Append($@"
-                {name} = component.{name},");
+                            getField = $"component.{name}";
+                            cast = $"({castString})";
+
+                            var nullCast = nullable ? castString.Substring(0, castString.Length - 1) : castString;
 
                             handleStateSetters.Append($@"
             if (state.{name} == null)
                 component.{name} = null!;
             else
                 component.{name} = new(state.{name});");
+
+                            deltaHandleFields.Append($@"
+                    var {name}Value = {cast} {fieldHandleValue};
+                    if ({name}Value == null)
+                        component.{name} = null!;
+                    else
+                        component.{name} = new {nullCast}({name}Value);");
+
+                            if (nullable)
+                            {
+                                deltaCreate.Append($@"
+                {name} = fullState.{name} == null ? null : new(fullState.{name}),");
+                            }
+                            else
+                            {
+                                deltaCreate.Append($@"
+                {name} = new(fullState.{name}),");
+                            }
+
+                            deltaApply.Add($@"
+                        if ({name} == null)
+                            fullState.{name} = null!;
+                        else
+                            fullState.{name} = new({name});");
                         }
                         else
                         {
-                            getStateInit.Append($@"
-                {name} = component.{name},");
+                            getField = $"component.{name}";
+                            cast = $"({castString})";
 
                             handleStateSetters.Append($@"
             component.{name} = state.{name};");
+
+                            deltaHandleFields.Append($@"
+                    component.{name} = {cast} {fieldHandleValue};");
+
+                            deltaCreate.Append($@"
+                {name} = fullState.{name},");
+
+                            deltaApply.Add($@"
+                        fullState.{name} = {name};");
                         }
 
                         break;
                 }
+
+                /*
+                 * End loop stuff
+                 */
+
+                networkedTypes.Add(networkedType);
+
+                getStateInit.Append($@"
+                {name} = {getField},");
+
+                deltaGetFields.Append(@$"    {name} = {getField}
+                        }};
+                        return;");
+
+                deltaHandleFields.Append($@"
+                }}
+                    break;");
+
             }
 
             var eventRaise = "";
@@ -278,19 +461,94 @@ namespace Robust.Shared.CompNetworkGenerator
             EntityManager.EventBus.RaiseComponentEvent(uid, component, ref ev);";
             }
 
+            var deltaGetState = "";
+            var deltaHandleState = "";
+            var deltaInterface = "";
+            var deltaCompFields = "";
+            var deltaNetRegister = "";
+
+            if (fieldDeltas)
+            {
+                for (var i = 0; i < fields.Count; i++)
+                {
+                    var name = fields[i].FieldName;
+                    string deltaStateName = $"{name}_FieldComponentState";
+                    var networkedType = networkedTypes[i];
+                    var apply = deltaApply[i];
+
+                    // Creates a state per field
+                    fieldStates.Append($@"
+    [Serializable, NetSerializable]
+    public sealed class {deltaStateName} : IComponentDeltaState<{stateName}>
+    {{
+        public {networkedType} {name} = default!;
+
+        public void ApplyToFullState({stateName} fullState)
+        {{{apply}
+        }}
+
+        public {stateName} CreateNewFullState({stateName} fullState)
+        {{
+            var newState = new {stateName}
+            {{{deltaCreate}
+            }};
+{apply}
+
+            return newState;
+        }}
+    }}
+                    ");
+                }
+
+                deltaNetRegister = $@"EntityManager.ComponentFactory.RegisterNetworkedFields<{classSymbol}>({fieldsStr});";
+
+                deltaGetState = @$"// Delta state
+            if (component is IComponentDelta delta && args.FromTick > component.CreationTick && delta.LastFieldUpdate >= args.FromTick)
+            {{
+                var fields = EntityManager.GetModifiedFields(component, args.FromTick);
+
+                // Try and get a matching delta state for the relevant dirty fields, otherwise fall back to full state.
+                switch (fields)
+                {{{deltaGetFields}
+                    default:
+                        break;
+                }}
+            }}";
+
+                deltaHandleState = $@"switch(args.Current)
+            {{{deltaHandleFields}
+                default:
+                    break;
+            }}";
+
+                deltaInterface = " : IComponentDelta";
+
+                deltaCompFields = @$"/// <inheritdoc />
+    public GameTick LastFieldUpdate {{ get; set; }} = GameTick.Zero;
+
+    /// <inheritdoc />
+    public GameTick[] LastModifiedFields {{ get; set; }} = Array.Empty<GameTick>();";
+            }
+
             return $@"// <auto-generated />
 #nullable enable
 using System;
 using Robust.Shared.GameStates;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Analyzers;
+using Robust.Shared.Collections;
 using Robust.Shared.Serialization;
 using Robust.Shared.Map;
+using Robust.Shared.Timing;
+using Robust.Shared.Utility;
+using System.Collections.Generic;
 
 namespace {nameSpace};
 
-public partial class {componentName}
+public partial class {componentName}{deltaInterface}
 {{
+    {deltaCompFields}
+
     [System.Serializable, NetSerializable]
     public sealed class {stateName} : IComponentState
     {{{stateFields}
@@ -301,12 +559,16 @@ public partial class {componentName}
     {{
         public override void Initialize()
         {{
+            {deltaNetRegister}
             SubscribeLocalEvent<{componentName}, ComponentGetState>(OnGetState);
             SubscribeLocalEvent<{componentName}, ComponentHandleState>(OnHandleState);
         }}
 
         private void OnGetState(EntityUid uid, {componentName} component, ref ComponentGetState args)
         {{
+            {deltaGetState}
+
+            // Get full state
             args.State = new {stateName}
             {{{getStateInit}
             }};
@@ -314,11 +576,15 @@ public partial class {componentName}
 
         private void OnHandleState(EntityUid uid, {componentName} component, ref ComponentHandleState args)
         {{
+            {deltaHandleState}
+
             if (args.Current is not {stateName} state)
                 return;
 {handleStateSetters}{eventRaise}
         }}
     }}
+
+    {fieldStates}
 }}
 ";
         }
@@ -341,13 +607,15 @@ public partial class {componentName}
                 {
                     var attr = type.Attribute;
                     var raiseEv = false;
-                    if (attr.ConstructorArguments is [{Value: bool raise}])
+                    var fieldDeltas = false;
+                    if (attr.ConstructorArguments is [{Value: bool raise}, {Value: bool fields}])
                     {
                         // Get the afterautohandle bool, which is first constructor arg
                         raiseEv = raise;
+                        fieldDeltas = fields;
                     }
 
-                    var source = GenerateSource(context, type.Type, comp, raiseEv);
+                    var source = GenerateSource(context, type.Type, comp, raiseEv, fieldDeltas);
                     // can be null if no members marked with network field, which already has a diagnostic, so
                     // just continue
                     if (source == null)

Robust.Shared.CompNetworkGenerator/Properties/launchSettings.json

@@ -0,0 +1,9 @@
+{
+    "$schema": "http://json.schemastore.org/launchsettings.json",
+    "profiles": {
+        "Comp State Generator": {
+            "commandName": "DebugRoslynComponent",
+            "targetProject": "../../Content.Shared/Content.Shared.csproj"
+        }
+    }
+}

Robust.Shared.Maths/MathHelper.cs

@@ -745,6 +745,21 @@ namespace Robust.Shared.Maths
             return remainder == T.Zero ? value : (value | mask) + T.One;
         }
 
+        public static bool IsValid(this float value)
+        {
+            if (float.IsNaN(value))
+            {
+                return false;
+            }
+
+            if (float.IsInfinity(value))
+            {
+                return false;
+            }
+
+            return true;
+        }
+
         #endregion Public Members
     }
 }

Robust.Shared.Maths/Matrix3Helpers.cs

@@ -73,7 +73,7 @@ public static class Matrix3Helpers
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static Angle Rotation(this Matrix3x2 t)
     {
-        return new Vector2(t.M11, t.M12).ToAngle();
+        return new Angle(Math.Atan2(t.M12, t.M11));
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]

Robust.Shared.Maths/Vector2Helpers.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Numerics;
 using System.Runtime.CompilerServices;
+using JetBrains.Annotations;
 
 namespace Robust.Shared.Maths;
 
@@ -14,6 +15,34 @@ public static class Vector2Helpers
     /// </summary>
     public static readonly Vector2 Half = new(0.5f, 0.5f);
 
+    public static bool IsValid(this Vector2 v)
+    {
+        if (float.IsNaN(v.X) || float.IsNaN(v.Y))
+        {
+            return false;
+        }
+
+        if (float.IsInfinity(v.X) || float.IsInfinity(v.Y))
+        {
+            return false;
+        }
+
+        return true;
+    }
+
+    public static Vector2 GetLengthAndNormalize(this Vector2 v, ref float length)
+    {
+        length = v.Length();
+        if (length < float.Epsilon)
+        {
+            return Vector2.Zero;
+        }
+
+        float invLength = 1.0f / length;
+        var n = new Vector2(invLength * v.X, invLength * v.Y);
+        return n;
+    }
+
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static Vector2 InterpolateCubic(Vector2 preA, Vector2 a, Vector2 b, Vector2 postB, float t)
     {
@@ -255,6 +284,12 @@ public static class Vector2Helpers
         return new(-s * a.Y, s * a.X);
     }
 
+    [Pure]
+    public static Vector2 RightPerp(this Vector2 v)
+    {
+        return new Vector2(v.Y, -v.X);
+    }
+
     /// <summary>
     /// Perform the cross product on a scalar and a vector. In 2D this produces
     /// a vector.

Robust.Shared/Analyzers/ComponentNetworkGeneratorAuxiliary.cs

@@ -19,9 +19,15 @@ public sealed class AutoGenerateComponentStateAttribute : Attribute
     /// </summary>
     public bool RaiseAfterAutoHandleState;
 
-    public AutoGenerateComponentStateAttribute(bool raiseAfterAutoHandleState = false)
+    /// <summary>
+    ///     Should delta states be generated for every field.
+    /// </summary>
+    public bool FieldDeltas;
+
+    public AutoGenerateComponentStateAttribute(bool raiseAfterAutoHandleState = false, bool fieldDeltas = false)
     {
         RaiseAfterAutoHandleState = raiseAfterAutoHandleState;
+        FieldDeltas = fieldDeltas;
     }
 }
 

Robust.Shared/Audio/Components/AudioComponent.cs

@@ -16,10 +16,10 @@ namespace Robust.Shared.Audio.Components;
 /// <summary>
 /// Stores the audio data for an audio entity.
 /// </summary>
-[RegisterComponent, NetworkedComponent, AutoGenerateComponentState(true), Access(typeof(SharedAudioSystem))]
+[RegisterComponent, NetworkedComponent, AutoGenerateComponentState(true, fieldDeltas: true), Access(typeof(SharedAudioSystem))]
 public sealed partial class AudioComponent : Component, IAudioSource
 {
-    [ViewVariables(VVAccess.ReadWrite), AutoNetworkedField, DataField, Access(Other = AccessPermissions.ReadWriteExecute)]
+    [AutoNetworkedField, DataField, Access(Other = AccessPermissions.ReadWriteExecute)]
     public AudioFlags Flags = AudioFlags.None;
 
     #region Filter

Robust.Shared/Audio/Components/AudioPresetComponent.cs

@@ -7,7 +7,7 @@ namespace Robust.Shared.Audio.Components;
 /// <summary>
 /// Marks this entity as being spawned for audio presets in case we need to reload.
 /// </summary>
-[RegisterComponent, NetworkedComponent, AutoGenerateComponentState, Access(typeof(SharedAudioSystem))]
+[RegisterComponent, NetworkedComponent, AutoGenerateComponentState(fieldDeltas: true), Access(typeof(SharedAudioSystem))]
 public sealed partial class AudioPresetComponent : Component
 {
     [AutoNetworkedField]

Robust.Shared/Audio/Systems/SharedAudioSystem.cs

@@ -105,6 +105,7 @@ public abstract partial class SharedAudioSystem : EntitySystem
         if (entity.Comp.PauseTime != null)
         {
             entity.Comp.PauseTime = entity.Comp.PauseTime.Value + timeOffset;
+            DirtyField(entity, nameof(AudioComponent.PauseTime));
 
             // Paused audio doesn't have TimedDespawn so.
         }
@@ -112,6 +113,7 @@ public abstract partial class SharedAudioSystem : EntitySystem
         {
             // Bump it back so the actual playback positions moves forward
             entity.Comp.AudioStart -= timeOffset;
+            DirtyField(entity, nameof(AudioComponent.AudioStart));
 
             // need to ensure it doesn't despawn too early.
             if (TryComp(entity.Owner, out TimedDespawnComponent? despawn))
@@ -121,8 +123,6 @@ public abstract partial class SharedAudioSystem : EntitySystem
         }
 
         entity.Comp.PlaybackPosition = position;
-        // Network the new playback position.
-        Dirty(entity);
     }
 
     /// <summary>
@@ -191,6 +191,9 @@ public abstract partial class SharedAudioSystem : EntitySystem
             var pauseOffset = Timing.CurTime - component.PauseTime;
             component.AudioStart += pauseOffset ?? TimeSpan.Zero;
             component.PlaybackPosition = (float) (Timing.CurTime - component.AudioStart).TotalSeconds;
+
+            DirtyField(entity.Value, component, nameof(AudioComponent.AudioStart));
+            DirtyField(entity.Value, component, nameof(AudioComponent.PlaybackPosition));
         }
 
         // If we were stopped then played then restart audiostart to now.
@@ -198,6 +201,9 @@ public abstract partial class SharedAudioSystem : EntitySystem
         {
             component.AudioStart = Timing.CurTime;
             component.PauseTime = null;
+
+            DirtyField(entity.Value, component, nameof(AudioComponent.AudioStart));
+            DirtyField(entity.Value, component, nameof(AudioComponent.PauseTime));
         }
 
         switch (state)
@@ -205,17 +211,21 @@ public abstract partial class SharedAudioSystem : EntitySystem
             case AudioState.Stopped:
                 component.AudioStart = Timing.CurTime;
                 component.PauseTime = null;
+                DirtyField(entity.Value, component, nameof(AudioComponent.AudioStart));
+                DirtyField(entity.Value, component, nameof(AudioComponent.PauseTime));
                 component.StopPlaying();
                 RemComp<TimedDespawnComponent>(entity.Value);
                 break;
             case AudioState.Paused:
                 // Set it to current time so we can easily unpause it later.
                 component.PauseTime = Timing.CurTime;
+                DirtyField(entity.Value, component, nameof(AudioComponent.PauseTime));
                 component.Pause();
                 RemComp<TimedDespawnComponent>(entity.Value);
                 break;
             case AudioState.Playing:
                 component.PauseTime = null;
+                DirtyField(entity.Value, component, nameof(AudioComponent.PauseTime));
                 component.StartPlaying();
 
                 // Reset TimedDespawn so the audio still gets cleaned up.
@@ -230,7 +240,7 @@ public abstract partial class SharedAudioSystem : EntitySystem
         }
 
         component.State = state;
-        Dirty(entity.Value, component);
+        DirtyField(entity.Value, component, nameof(AudioComponent.State));
     }
 
     protected void SetZOffset(float value)
@@ -375,7 +385,7 @@ public abstract partial class SharedAudioSystem : EntitySystem
 
         component.Params.Volume = value;
         component.Volume = value;
-        Dirty(entity.Value, component);
+        DirtyField(entity.Value, component, nameof(AudioComponent.Params));
     }
 
     #endregion

Robust.Shared/CVars.cs

@@ -628,6 +628,43 @@ namespace Robust.Shared
         public static readonly CVarDef<string> StatusConnectAddress =
             CVarDef.Create("status.connectaddress", "", CVar.ARCHIVE | CVar.SERVERONLY);
 
+        /// <summary>
+        /// HTTP(S) link to a privacy policy that the user must accept to connect to the server.
+        /// </summary>
+        /// <remarks>
+        /// This must be set along with <see cref="StatusPrivacyPolicyIdentifier"/> and
+        /// <see cref="StatusPrivacyPolicyVersion"/> for the user to be prompted about a privacy policy.
+        /// </remarks>
+        public static readonly CVarDef<string> StatusPrivacyPolicyLink =
+            CVarDef.Create("status.privacy_policy_link", "https://example.com/privacy", CVar.SERVER | CVar.REPLICATED);
+
+        /// <summary>
+        /// An identifier for privacy policy specified by <see cref="StatusPrivacyPolicyLink"/>.
+        /// This must be globally unique.
+        /// </summary>
+        /// <remarks>
+        /// <para>
+        /// This value must be globally unique per server community. Servers that want to enforce a
+        /// privacy policy should set this to a value that is unique to their server and, preferably, recognizable.
+        /// </para>
+        /// <para>
+        /// This value is stored by the launcher to keep track of what privacy policies a player has accepted.
+        /// </para>
+        /// </remarks>
+        public static readonly CVarDef<string> StatusPrivacyPolicyIdentifier =
+            CVarDef.Create("status.privacy_policy_identifier", "", CVar.SERVER | CVar.REPLICATED);
+
+        /// <summary>
+        /// A "version" for the privacy policy specified by <see cref="StatusPrivacyPolicyLink"/>.
+        /// </summary>
+        /// <remarks>
+        /// <para>
+        /// This parameter is stored by the launcher and should be modified whenever your server's privacy policy changes.
+        /// </para>
+        /// </remarks>
+        public static readonly CVarDef<string> StatusPrivacyPolicyVersion =
+            CVarDef.Create("status.privacy_policy_version", "", CVar.SERVER | CVar.REPLICATED);
+
         /*
          * BUILD
          */

Robust.Shared/Collections/ValueList.cs

@@ -5,6 +5,7 @@ using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Numerics;
 using System.Runtime.CompilerServices;
@@ -589,6 +590,12 @@ public struct ValueList<T> : IEnumerable<T>
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public void AddRange(Span<T> span)
+    {
+        AddRange((ReadOnlySpan<T>) span);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public void AddRange(ReadOnlySpan<T> span)
     {
         var spanCount = span.Length;
         EnsureCapacity(Count + spanCount);
@@ -618,4 +625,72 @@ public struct ValueList<T> : IEnumerable<T>
             Add(result);
         }
     }
+
+    /// <summary>
+    /// Push a value onto the end of this list. This is equivalent to <see cref="Add"/>.
+    /// </summary>
+    /// <remarks>
+    /// This method is added to provide completeness with other stack-like functions.
+    /// </remarks>
+    /// <param name="item">The item to add to the list.</param>
+    public void Push(T item)
+    {
+        Add(item);
+    }
+
+    /// <summary>
+    /// Remove and return the value at the end of the list.
+    /// </summary>
+    /// <exception cref="InvalidOperationException">Thrown if the list is empty.</exception>
+    public T Pop()
+    {
+        if (!TryPop(out var value))
+            throw new InvalidOperationException("List is empty");
+
+        return value;
+    }
+
+    /// <summary>
+    /// Return the value at the end of the list, but do not remove it.
+    /// </summary>
+    /// <exception cref="InvalidOperationException">Thrown if the list is empty.</exception>
+    public T Peek()
+    {
+        if (!TryPeek(out var value))
+            throw new InvalidOperationException("List is empty");
+
+        return value;
+    }
+
+    /// <summary>
+    /// Remove and return the value at the end of the list, only if the list is not empty.
+    /// </summary>
+    /// <returns>True if the list was not empty and an item was removed.</returns>
+    public bool TryPop([MaybeNullWhen(false)] out T value)
+    {
+        if (Count == 0)
+        {
+            value = default;
+            return false;
+        }
+
+        value = _items![--Count];
+        return true;
+    }
+
+    /// <summary>
+    /// Remove and return the value at the end of the list, only if the list is not empty.
+    /// </summary>
+    /// <returns>True if the list was not empty and an item was removed.</returns>
+    public bool TryPeek([MaybeNullWhen(false)] out T value)
+    {
+        if (Count == 0)
+        {
+            value = default;
+            return false;
+        }
+
+        value = _items![Count];
+        return true;
+    }
 }

Robust.Shared/Containers/SharedContainerSystem.cs

@@ -367,7 +367,7 @@ namespace Robust.Shared.Containers
             if (!xform.ParentUid.Valid)
                 return false;
 
-            if (entityQuery.Resolve(xform.ParentUid, ref foundComponent, false))
+            if (entityQuery.TryComp(xform.ParentUid, out foundComponent))
                 return true;
 
             return TryFindComponentOnEntityContainerOrParent(xform.ParentUid, entityQuery, ref foundComponent);

Robust.Shared/ContentPack/AssemblyTypeChecker.ReportBadReferences.cs

@@ -39,7 +39,7 @@ internal sealed partial class AssemblyTypeChecker
             {
                 if (instruction.TryGetEntityHandle(out var handle))
                 {
-                    if (refs.Contains(handle))
+                    if (refs.Overlaps(ExpandHandle(reader, handle)))
                     {
                         var type = GetTypeFromDefinition(reader, methodDef.GetDeclaringType());
                         _sawmill.Error(
@@ -56,6 +56,12 @@ internal sealed partial class AssemblyTypeChecker
     {
         switch (handle.Kind)
         {
+            case HandleKind.MethodSpecification:
+                var methodSpec = reader.GetMethodSpecification((MethodSpecificationHandle)handle);
+                var methodProvider = new TypeProvider();
+                var spec = methodSpec.DecodeSignature(methodProvider, 0);
+                return $"{DisplayHandle(reader, methodSpec.Method)}<{string.Join(", ", spec.Select(t => t.ToString()))}>";
+
             case HandleKind.MemberReference:
                 var memberRef = reader.GetMemberReference((MemberReferenceHandle)handle);
                 var name = reader.GetString(memberRef.Name);
@@ -92,6 +98,17 @@ internal sealed partial class AssemblyTypeChecker
         handles.UnionWith(toAdd);
     }
 
+    private static IEnumerable<EntityHandle> ExpandHandle(MetadataReader reader, EntityHandle handle)
+    {
+        // Annoying, S.R.M gives no way to iterate over the MethodSpec table.
+        // This means the only way to correlate MethodSpec references is to do it for each handle.
+
+        yield return handle;
+
+        if (handle.Kind == HandleKind.MethodSpecification)
+            yield return reader.GetMethodSpecification((MethodSpecificationHandle)handle).Method;
+    }
+
     private readonly struct ILInstruction
     {
         public readonly ILOpCode OpCode;

Robust.Shared/GameObjects/ComponentFactory.cs

@@ -175,6 +175,41 @@ namespace Robust.Shared.GameObjects
             return name;
         }
 
+        /// <inheritdoc />
+        public void RegisterNetworkedFields<T>(params string[] fields) where T : IComponent
+        {
+            var compReg = GetRegistration(CompIdx.Index<T>());
+            RegisterNetworkedFields(compReg, fields);
+        }
+
+        /// <inheritdoc />
+        public void RegisterNetworkedFields(ComponentRegistration compReg, params string[] fields)
+        {
+            // Nothing to do.
+            if (compReg.NetworkedFields.Length > 0 || fields.Length == 0)
+                return;
+
+            DebugTools.Assert(fields.Length <= 32);
+
+            if (fields.Length > 32)
+            {
+                throw new NotSupportedException(
+                    "Components with more than 32 networked fields unsupported! Consider splitting it up or making a pr for 64-bit flags");
+            }
+
+            compReg.NetworkedFields = fields;
+            var lookup = new Dictionary<string, int>(fields.Length);
+            var i = 0;
+
+            foreach (var field in fields)
+            {
+                lookup[field] = i;
+                i++;
+            }
+
+            compReg.NetworkedFieldLookup = lookup.ToFrozenDictionary();
+        }
+
         public void IgnoreMissingComponents(string postfix = "")
         {
             if (_ignoreMissingComponentPostfix != null && _ignoreMissingComponentPostfix != postfix)

Robust.Shared/GameObjects/ComponentRegistration.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Frozen;
 using System.Collections.Generic;
 using Robust.Shared.Collections;
 using Robust.Shared.GameStates;
@@ -39,6 +40,13 @@ public sealed class ComponentRegistration
     /// </summary>
     public Type Type { get; }
 
+    /// <summary>
+    /// Fields that are networked for this component. Used for delta states.
+    /// </summary>
+    public string[] NetworkedFields = [];
+
+    public FrozenDictionary<string, int> NetworkedFieldLookup = FrozenDictionary<string, int>.Empty;
+
     // Internal for sandboxing.
     // Avoid content passing an instance of this to ComponentFactory to get any type they want instantiated.
     internal ComponentRegistration(string name, Type type, CompIdx idx, bool unsaved = false)

Robust.Shared/GameObjects/Components/CollisionWakeComponent.cs

@@ -1,30 +1,15 @@
-using System;
 using Robust.Shared.GameStates;
-using Robust.Shared.IoC;
-using Robust.Shared.Serialization;
 using Robust.Shared.Serialization.Manager.Attributes;
 
-namespace Robust.Shared.GameObjects
+namespace Robust.Shared.GameObjects;
+
+/// <summary>
+///     An optimisation component for stuff that should be set as collidable when it's awake and non-collidable when asleep.
+/// </summary>
+[RegisterComponent, NetworkedComponent, AutoGenerateComponentState]
+[Access(typeof(CollisionWakeSystem))]
+public sealed partial class CollisionWakeComponent : Component
 {
-    /// <summary>
-    ///     An optimisation component for stuff that should be set as collidable when it's awake and non-collidable when asleep.
-    /// </summary>
-    [RegisterComponent, NetworkedComponent()]
-    [Access(typeof(CollisionWakeSystem))]
-    public sealed partial class CollisionWakeComponent : Component
-    {
-        [DataField("enabled")]
-        public bool Enabled = true;
-
-        [Serializable, NetSerializable]
-        public sealed class CollisionWakeState : ComponentState
-        {
-            public bool Enabled { get; }
-
-            public CollisionWakeState(bool enabled)
-            {
-                Enabled = enabled;
-            }
-        }
-    }
+    [DataField, AutoNetworkedField]
+    public bool Enabled = true;
 }

Robust.Shared/GameObjects/Components/Eye/EyeComponent.cs

@@ -8,7 +8,7 @@ using Robust.Shared.ViewVariables;
 
 namespace Robust.Shared.GameObjects
 {
-    [RegisterComponent, NetworkedComponent, Access(typeof(SharedEyeSystem)), AutoGenerateComponentState(true)]
+    [RegisterComponent, NetworkedComponent, Access(typeof(SharedEyeSystem)), AutoGenerateComponentState(true, fieldDeltas: true)]
     public sealed partial class EyeComponent : Component
     {
         public const int DefaultVisibilityMask = 1;
@@ -24,33 +24,33 @@ namespace Robust.Shared.GameObjects
         ///     that without messing with the main viewport's eye. This is important as there are some overlays that are
         ///     only be drawn if that viewport's eye belongs to the currently controlled entity.
         /// </remarks>
-        [ViewVariables, DataField("target"), AutoNetworkedField]
+        [DataField, AutoNetworkedField]
         public EntityUid? Target;
 
-        [ViewVariables(VVAccess.ReadWrite), DataField("drawFov"), AutoNetworkedField]
+        [DataField, AutoNetworkedField]
         public bool DrawFov = true;
 
-        [ViewVariables(VVAccess.ReadWrite), AutoNetworkedField]
+        [AutoNetworkedField]
         public bool DrawLight = true;
 
         // yes it's not networked, don't ask.
-        [ViewVariables(VVAccess.ReadWrite), DataField("rotation")]
+        [DataField]
         public Angle Rotation;
 
-        [ViewVariables(VVAccess.ReadWrite), DataField("zoom")]
+        [DataField]
         public Vector2 Zoom = Vector2.One;
 
         /// <summary>
         /// Eye offset, relative to the map, and not affected by <see cref="Rotation"/>
         /// </summary>
-        [ViewVariables(VVAccess.ReadWrite), DataField("offset"), AutoNetworkedField]
+        [DataField, AutoNetworkedField]
         public Vector2 Offset;
 
         /// <summary>
         ///     The visibility mask for this eye.
         ///     The player will be able to get updates for entities whose layers match the mask.
         /// </summary>
-        [ViewVariables(VVAccess.ReadWrite), DataField("visMask", customTypeSerializer:typeof(FlagSerializer<VisibilityMaskLayer>)), AutoNetworkedField]
+        [DataField("visMask", customTypeSerializer:typeof(FlagSerializer<VisibilityMaskLayer>)), AutoNetworkedField]
         public int VisibilityMask = DefaultVisibilityMask;
 
         /// <summary>

Robust.Shared/GameObjects/Components/UserInterface/BoundUserInterface.cs

@@ -59,6 +59,27 @@ namespace Robust.Shared.GameObjects
         {
         }
 
+        /// <summary>
+        /// Calls <see cref="UpdateState"/> if the supplied state exists and calls <see cref="Update"/>
+        /// </summary>
+        public void Update<T>() where T : BoundUserInterfaceState
+        {
+            if (UiSystem.TryGetUiState<T>(Owner, UiKey, out var state))
+            {
+                UpdateState(state);
+            }
+
+            Update();
+        }
+
+        /// <summary>
+        /// Generic update method called whenever the BUI should update.
+        /// </summary>
+        public virtual void Update()
+        {
+
+        }
+
         /// <summary>
         /// Helper method that gets called upon prototype reload.
         /// </summary>

Robust.Shared/GameObjects/Components/UserInterface/UserInterfaceComponent.cs

@@ -3,14 +3,22 @@ using System.Collections.Generic;
 using Robust.Shared.GameStates;
 using Robust.Shared.Player;
 using Robust.Shared.Serialization;
+using Robust.Shared.Serialization.Manager;
 using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.Timing;
 using Robust.Shared.ViewVariables;
 
 namespace Robust.Shared.GameObjects
 {
     [RegisterComponent, NetworkedComponent, Access(typeof(SharedUserInterfaceSystem))]
-    public sealed partial class UserInterfaceComponent : Component
+    public sealed partial class UserInterfaceComponent : Component, IComponentDelta
     {
+        /// <inheritdoc />
+        public GameTick LastFieldUpdate { get; set; }
+
+        /// <inheritdoc />
+        public GameTick[] LastModifiedFields { get; set; }
+
         /// <summary>
         /// The currently open interfaces. Used clientside to store the UI.
         /// </summary>
@@ -30,19 +38,71 @@ namespace Robust.Shared.GameObjects
         /// Legacy data, new BUIs should be using comp states.
         /// </summary>
         public Dictionary<Enum, BoundUserInterfaceState> States = new();
+    }
 
-        [Serializable, NetSerializable]
-        internal sealed class UserInterfaceComponentState(
-            Dictionary<Enum, List<NetEntity>> actors,
-            Dictionary<Enum, BoundUserInterfaceState> states,
-            Dictionary<Enum, InterfaceData> data)
-            : IComponentState
+    [Serializable, NetSerializable]
+    internal sealed class UserInterfaceComponentState(
+        Dictionary<Enum, List<NetEntity>> actors,
+        Dictionary<Enum, BoundUserInterfaceState> states,
+        Dictionary<Enum, InterfaceData> data)
+        : IComponentState
+    {
+        public Dictionary<Enum, List<NetEntity>> Actors = actors;
+
+        public Dictionary<Enum, BoundUserInterfaceState> States = states;
+
+        public Dictionary<Enum, InterfaceData> Data = data;
+    }
+
+    [Serializable, NetSerializable]
+    internal sealed class UserInterfaceActorsDeltaState : IComponentDeltaState<UserInterfaceComponentState>
+    {
+        public Dictionary<Enum, List<NetEntity>> Actors = new();
+
+        public void ApplyToFullState(UserInterfaceComponentState fullState)
         {
-            public Dictionary<Enum, List<NetEntity>> Actors = actors;
+            fullState.Actors.Clear();
 
-            public Dictionary<Enum, BoundUserInterfaceState> States = states;
+            foreach (var (key, value) in Actors)
+            {
+                fullState.Actors.Add(key, value);
+            }
+        }
 
-            public Dictionary<Enum, InterfaceData> Data = data;
+        public UserInterfaceComponentState CreateNewFullState(UserInterfaceComponentState fullState)
+        {
+            var newState = new UserInterfaceComponentState(
+                new Dictionary<Enum, List<NetEntity>>(Actors),
+                new(fullState.States),
+                new(fullState.Data));
+
+            return newState;
+        }
+    }
+
+    [Serializable, NetSerializable]
+    internal sealed class UserInterfaceStatesDeltaState : IComponentDeltaState<UserInterfaceComponentState>
+    {
+        public Dictionary<Enum, BoundUserInterfaceState> States = new();
+
+        public void ApplyToFullState(UserInterfaceComponentState fullState)
+        {
+            fullState.States.Clear();
+
+            foreach (var (key, value) in States)
+            {
+                fullState.States.Add(key, value);
+            }
+        }
+
+        public UserInterfaceComponentState CreateNewFullState(UserInterfaceComponentState fullState)
+        {
+            var newState = new UserInterfaceComponentState(
+                new Dictionary<Enum, List<NetEntity>>(fullState.Actors),
+                new(States),
+                new(fullState.Data));
+
+            return newState;
         }
     }
 
@@ -69,6 +129,12 @@ namespace Robust.Shared.GameObjects
         [DataField]
         public bool RequireInputValidation = true;
 
+        public InterfaceData(string clientType, float interactionRange = 2f, bool requireInputValidation = true)
+        {
+            ClientType = clientType;
+            InteractionRange = interactionRange;
+            RequireInputValidation = requireInputValidation;
+        }
         public InterfaceData(InterfaceData data)
         {
             ClientType = data.ClientType;

Robust.Shared/GameObjects/EntityManager.ComponentDeltas.cs

@@ -0,0 +1,78 @@
+using Robust.Shared.Timing;
+
+namespace Robust.Shared.GameObjects;
+
+public abstract partial class EntityManager
+{
+    public uint GetModifiedFields(IComponentDelta delta, GameTick fromTick)
+    {
+        uint fields = 0;
+
+        for (var i = 0; i < delta.LastModifiedFields.Length; i++)
+        {
+            var lastUpdate = delta.LastModifiedFields[i];
+
+            // Field not dirty
+            if (lastUpdate < fromTick)
+                continue;
+
+            fields |= (uint) (1 << i);
+        }
+
+        return fields;
+    }
+
+    public void DirtyField(EntityUid uid, IComponentDelta comp, string fieldName, MetaDataComponent? metadata = null)
+    {
+        var compReg = ComponentFactory.GetRegistration(comp);
+
+        if (!compReg.NetworkedFieldLookup.TryGetValue(fieldName, out var idx))
+        {
+            _sawmill.Error($"Tried to dirty delta field {fieldName} on {ToPrettyString(uid)} that isn't implemented.");
+            return;
+        }
+
+        var curTick = _gameTiming.CurTick;
+        comp.LastFieldUpdate = curTick;
+        comp.LastModifiedFields[idx] = curTick;
+        Dirty(uid, comp, metadata);
+    }
+
+    public void DirtyField<T>(EntityUid uid, T comp, string fieldName, MetaDataComponent? metadata = null)
+        where T : IComponentDelta
+    {
+        var compReg = ComponentFactory.GetRegistration(CompIdx.Index<T>());
+
+        if (!compReg.NetworkedFieldLookup.TryGetValue(fieldName, out var idx))
+        {
+            _sawmill.Error($"Tried to dirty delta field {fieldName} on {ToPrettyString(uid)} that isn't implemented.");
+            return;
+        }
+
+        var curTick = _gameTiming.CurTick;
+        comp.LastFieldUpdate = curTick;
+        comp.LastModifiedFields[idx] = curTick;
+        Dirty(uid, comp, metadata);
+    }
+}
+
+/// <summary>
+/// Indicates this component supports delta states.
+/// </summary>
+public partial interface IComponentDelta : IComponent
+{
+    // TODO: This isn't entirely robust but not sure how else to handle this?
+    /// <summary>
+    /// Track last time a field was dirtied. if the full component dirty exceeds this then we send a full state update.
+    /// </summary>
+    public GameTick LastFieldUpdate { get; set; }
+
+    /// <summary>
+    /// Stores the last modified tick for fields.
+    /// </summary>
+    public GameTick[] LastModifiedFields
+    {
+        get;
+        set;
+    }
+}

Robust.Shared/GameObjects/EntityManager.Components.cs

@@ -372,6 +372,13 @@ namespace Robust.Shared.GameObjects
                 metadata.NetComponents.Add(netId, component);
             }
 
+            if (component is IComponentDelta delta)
+            {
+                var curTick = _gameTiming.CurTick;
+                delta.LastModifiedFields = new GameTick[reg.NetworkedFields.Length];
+                Array.Fill(delta.LastModifiedFields, curTick);
+            }
+
             component.Networked = reg.NetID != null;
 
             var eventArgs = new AddedComponentEventArgs(new ComponentEventArgs(component, uid), reg);
@@ -707,6 +714,7 @@ namespace Robust.Shared.GameObjects
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [Pure]
         public bool HasComponent<T>(EntityUid uid) where T : IComponent
         {
             var dict = _entTraitArray[CompIdx.ArrayIndex<T>()];
@@ -716,13 +724,15 @@ namespace Robust.Shared.GameObjects
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool HasComponent<T>(EntityUid? uid) where T : IComponent
+        [Pure]
+        public bool HasComponent<T>([NotNullWhen(true)] EntityUid? uid) where T : IComponent
         {
             return uid.HasValue && HasComponent<T>(uid.Value);
         }
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [Pure]
         public bool HasComponent(EntityUid uid, Type type)
         {
             var dict = _entTraitDict[type];
@@ -731,7 +741,8 @@ namespace Robust.Shared.GameObjects
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool HasComponent(EntityUid? uid, Type type)
+        [Pure]
+        public bool HasComponent([NotNullWhen(true)] EntityUid? uid, Type type)
         {
             if (!uid.HasValue)
             {
@@ -744,6 +755,7 @@ namespace Robust.Shared.GameObjects
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [Pure]
         public bool HasComponent(EntityUid uid, ushort netId, MetaDataComponent? meta = null)
         {
             if (!MetaQuery.Resolve(uid, ref meta))
@@ -754,7 +766,8 @@ namespace Robust.Shared.GameObjects
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool HasComponent(EntityUid? uid, ushort netId, MetaDataComponent? meta = null)
+        [Pure]
+        public bool HasComponent([NotNullWhen(true)] EntityUid? uid, ushort netId, MetaDataComponent? meta = null)
         {
             if (!uid.HasValue)
             {
@@ -821,6 +834,7 @@ namespace Robust.Shared.GameObjects
         }
 
         /// <inheritdoc />
+        [Pure]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public T GetComponent<T>(EntityUid uid) where T : IComponent
         {
@@ -837,6 +851,7 @@ namespace Robust.Shared.GameObjects
             throw new KeyNotFoundException($"Entity {uid} does not have a component of type {typeof(T)}");
         }
 
+        [Pure]
         public IComponent GetComponent(EntityUid uid, CompIdx type)
         {
             var dict = _entTraitArray[type.Value];
@@ -850,6 +865,7 @@ namespace Robust.Shared.GameObjects
         }
 
         /// <inheritdoc />
+        [Pure]
         public IComponent GetComponent(EntityUid uid, Type type)
         {
             // ReSharper disable once InvertIf
@@ -866,12 +882,14 @@ namespace Robust.Shared.GameObjects
         }
 
         /// <inheritdoc />
+        [Pure]
         public IComponent GetComponent(EntityUid uid, ushort netId, MetaDataComponent? meta = null)
         {
             return (meta ?? MetaQuery.GetComponentInternal(uid)).NetComponents[netId];
         }
 
         /// <inheritdoc />
+        [Pure]
         public IComponent GetComponentInternal(EntityUid uid, CompIdx type)
         {
             var dict = _entTraitArray[type.Value];
@@ -1450,6 +1468,7 @@ namespace Robust.Shared.GameObjects
         }
 
         /// <inheritdoc />
+        [Pure]
         public IComponentState? GetComponentState(IEventBus eventBus, IComponent component, ICommonSession? session, GameTick fromTick)
         {
             DebugTools.Assert(component.NetSyncEnabled, $"Attempting to get component state for an un-synced component: {component.GetType()}");
@@ -1578,7 +1597,7 @@ namespace Robust.Shared.GameObjects
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         [Pure]
-        public bool HasComp(EntityUid? uid) => HasComponent(uid);
+        public bool HasComp([NotNullWhen(true)] EntityUid? uid) => HasComponent(uid);
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         [Pure]
@@ -1589,7 +1608,7 @@ namespace Robust.Shared.GameObjects
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         [Pure]
-        public bool HasComponent(EntityUid? uid)
+        public bool HasComponent([NotNullWhen(true)] EntityUid? uid)
         {
             return uid != null && HasComponent(uid.Value);
         }

Robust.Shared/GameObjects/EntitySystem.Proxy.cs

@@ -148,6 +148,29 @@ public partial class EntitySystem
         EntityManager.Dirty(uid, component, meta);
     }
 
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected void DirtyField(EntityUid uid, IComponentDelta delta, string fieldName, MetaDataComponent? meta = null)
+    {
+        EntityManager.DirtyField(uid, delta, fieldName, meta);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected void DirtyField<T>(Entity<T?> entity, string fieldName, MetaDataComponent? meta = null)
+        where T : IComponentDelta
+    {
+        if (!Resolve(entity.Owner, ref entity.Comp))
+            return;
+
+        EntityManager.DirtyField(entity.Owner, entity.Comp, fieldName, meta);
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected void DirtyField<T>(EntityUid uid, T component, string fieldName, MetaDataComponent? meta = null)
+        where T : IComponentDelta
+    {
+        EntityManager.DirtyField(uid, component, fieldName, meta);
+    }
+
     /// <summary>
     ///     Marks a component as dirty. This also implicitly dirties the entity this component belongs to.
     /// </summary>

Robust.Shared/GameObjects/IComponentFactory.cs

@@ -77,6 +77,10 @@ namespace Robust.Shared.GameObjects
         /// <returns>The availability of the component.</returns>
         ComponentAvailability GetComponentAvailability(string componentName, bool ignoreCase = false);
 
+        public void RegisterNetworkedFields<T>(params string[] fields) where T : IComponent;
+
+        public void RegisterNetworkedFields(ComponentRegistration compReg, params string[] fields);
+
         /// <summary>
         /// Slow-path for Type -> CompIdx mapping without generics.
         /// </summary>

Robust.Shared/GameObjects/IEntityManager.Network.cs

@@ -6,6 +6,11 @@ namespace Robust.Shared.GameObjects;
 
 public partial interface IEntityManager
 {
+    public void DirtyField(EntityUid uid, IComponentDelta delta, string fieldName, MetaDataComponent? metadata = null);
+
+    public void DirtyField<T>(EntityUid uid, T component, string fieldName, MetaDataComponent? metadata = null)
+        where T : IComponentDelta;
+
     /// <summary>
     /// Tries to parse a string as a NetEntity and return the relevant EntityUid.
     /// </summary>

Robust.Shared/GameObjects/Systems/CollisionWakeSystem.cs

@@ -1,4 +1,3 @@
-using Robust.Shared.GameStates;
 using Robust.Shared.IoC;
 using Robust.Shared.Map;
 using Robust.Shared.Physics;
@@ -17,9 +16,6 @@ namespace Robust.Shared.GameObjects
             base.Initialize();
             SubscribeLocalEvent<CollisionWakeComponent, ComponentShutdown>(OnRemove);
 
-            SubscribeLocalEvent<CollisionWakeComponent, ComponentGetState>(OnGetState);
-            SubscribeLocalEvent<CollisionWakeComponent, ComponentHandleState>(OnHandleState);
-
             SubscribeLocalEvent<CollisionWakeComponent, JointAddedEvent>(OnJointAdd);
             SubscribeLocalEvent<CollisionWakeComponent, JointRemovedEvent>(OnJointRemove);
 
@@ -43,22 +39,6 @@ namespace Robust.Shared.GameObjects
             Dirty(uid, component);
         }
 
-        private void OnHandleState(EntityUid uid, CollisionWakeComponent component, ref ComponentHandleState args)
-        {
-            if (args.Current is CollisionWakeComponent.CollisionWakeState state)
-                component.Enabled = state.Enabled;
-
-            // Note, this explicitly does not update PhysicsComponent.CanCollide. The physics component should perform
-            // its own state-handling logic. Additionally, if we wanted to set it you would have to ensure that things
-            // like the join-component and physics component have already handled their states, otherwise CanCollide may
-            // be set incorrectly and leave the client with a bad state.
-        }
-
-        private void OnGetState(EntityUid uid, CollisionWakeComponent component, ref ComponentGetState args)
-        {
-            args.State = new CollisionWakeComponent.CollisionWakeState(component.Enabled);
-        }
-
         private void OnRemove(EntityUid uid, CollisionWakeComponent component, ComponentShutdown args)
         {
             if (component.Enabled

Robust.Shared/GameObjects/Systems/EntityLookupSystem.ComponentQueries.cs

@@ -175,7 +175,7 @@ public sealed partial class EntityLookupSystem
 
         return;
 
-        static bool PhysicsQuery<T>(ref QueryState<T> state, in FixtureProxy value) where T : IComponent
+        static bool PhysicsQuery(ref QueryState<T> state, in FixtureProxy value)
         {
             if (!state.Sensors && !value.Fixture.Hard)
                 return true;
@@ -196,7 +196,7 @@ public sealed partial class EntityLookupSystem
             return true;
         }
 
-        static bool SundriesQuery<T>(ref QueryState<T> state, in EntityUid value) where T : IComponent
+        static bool SundriesQuery(ref QueryState<T> state, in EntityUid value)
         {
             if (!state.Query.TryGetComponent(value, out var comp))
                 return true;
@@ -318,7 +318,7 @@ public sealed partial class EntityLookupSystem
 
         return state.Found;
 
-        static bool PhysicsQuery<T>(ref AnyQueryState<T> state, in FixtureProxy value) where T : IComponent
+        static bool PhysicsQuery(ref AnyQueryState<T> state, in FixtureProxy value)
         {
             if (value.Entity == state.Ignored)
                 return true;

Robust.Shared/GameObjects/Systems/SharedEyeSystem.cs

@@ -63,7 +63,7 @@ public abstract class SharedEyeSystem : EntitySystem
 
         eyeComponent.Offset = value;
         eyeComponent.Eye.Offset = value;
-        Dirty(uid, eyeComponent);
+        DirtyField(uid, eyeComponent, nameof(EyeComponent.Offset));
     }
 
     public void SetDrawFov(EntityUid uid, bool value, EyeComponent? eyeComponent = null)
@@ -76,7 +76,7 @@ public abstract class SharedEyeSystem : EntitySystem
 
         eyeComponent.DrawFov = value;
         eyeComponent.Eye.DrawFov = value;
-        Dirty(uid, eyeComponent);
+        DirtyField(uid, eyeComponent, nameof(EyeComponent.DrawFov));
     }
 
     public void SetDrawLight(Entity<EyeComponent?> entity, bool value)
@@ -89,7 +89,7 @@ public abstract class SharedEyeSystem : EntitySystem
 
         entity.Comp.DrawLight = value;
         entity.Comp.Eye.DrawLight = value;
-        Dirty(entity);
+        DirtyField(entity, nameof(EyeComponent.DrawLight));
     }
 
     public void SetRotation(EntityUid uid, Angle rotation, EyeComponent? eyeComponent = null)
@@ -127,7 +127,7 @@ public abstract class SharedEyeSystem : EntitySystem
         }
 
         eyeComponent.Target = value;
-        Dirty(uid, eyeComponent);
+        DirtyField(uid, eyeComponent, nameof(EyeComponent.Target));
     }
 
     public void SetZoom(EntityUid uid, Vector2 value, EyeComponent? eyeComponent = null)
@@ -168,6 +168,6 @@ public abstract class SharedEyeSystem : EntitySystem
             return;
 
         eyeComponent.VisibilityMask = value;
-        Dirty(uid, eyeComponent);
+        DirtyField(uid, eyeComponent, nameof(EyeComponent.VisibilityMask));
     }
 }

Robust.Shared/GameObjects/Systems/SharedMapSystem.Grid.cs

@@ -532,7 +532,7 @@ public abstract partial class SharedMapSystem
     private void OnGridRemove(EntityUid uid, MapGridComponent component, ComponentShutdown args)
     {
         Log.Info($"Removing grid {ToPrettyString(uid)}");
-        if (TryComp<TransformComponent>(uid, out var xform) && xform.MapUid != null)
+        if (TryComp(uid, out TransformComponent? xform) && xform.MapUid != null)
         {
             RemoveGrid(uid, component, xform.MapUid.Value);
         }

Robust.Shared/GameObjects/Systems/SharedTransformSystem.Component.cs

@@ -719,8 +719,7 @@ public abstract partial class SharedTransformSystem
             component.LocalRotation,
             parent,
             component.NoLocalRotation,
-            component.Anchored,
-            component.GridTraversal);
+            component.Anchored);
     }
 
     internal void OnHandleState(EntityUid uid, TransformComponent xform, ref ComponentHandleState args)

Robust.Shared/GameObjects/Systems/SharedTransformSystem.cs

@@ -337,8 +337,6 @@ namespace Robust.Shared.GameObjects
         /// </summary>
         public readonly bool Anchored;
 
-        public readonly bool GridTraversal;
-
         /// <summary>
         ///     Constructs a new state snapshot of a TransformComponent.
         /// </summary>
@@ -346,14 +344,13 @@ namespace Robust.Shared.GameObjects
         /// <param name="rotation">Current direction offset of this entity.</param>
         /// <param name="parentId">Current parent transform of this entity.</param>
         /// <param name="noLocalRotation"></param>
-        public TransformComponentState(Vector2 localPosition, Angle rotation, NetEntity parentId, bool noLocalRotation, bool anchored, bool gridTraversal)
+        public TransformComponentState(Vector2 localPosition, Angle rotation, NetEntity parentId, bool noLocalRotation, bool anchored)
         {
             LocalPosition = localPosition;
             Rotation = rotation;
             ParentID = parentId;
             NoLocalRotation = noLocalRotation;
             Anchored = anchored;
-            GridTraversal = gridTraversal;
         }
     }
 }

Robust.Shared/GameObjects/Systems/SharedUserInterfaceSystem.cs

@@ -44,6 +44,11 @@ public abstract class SharedUserInterfaceSystem : EntitySystem
     {
         base.Initialize();
 
+        EntityManager.ComponentFactory.RegisterNetworkedFields<UserInterfaceComponent>(
+            nameof(UserInterfaceComponent.Actors),
+            nameof(UserInterfaceComponent.Interfaces),
+            nameof(UserInterfaceComponent.States));
+
         _ignoreUIRangeQuery = GetEntityQuery<IgnoreUIRangeComponent>();
         _xformQuery = GetEntityQuery<TransformComponent>();
         UIQuery = GetEntityQuery<UserInterfaceComponent>();
@@ -204,7 +209,7 @@ public abstract class SharedUserInterfaceSystem : EntitySystem
         if (actors.Count == 0)
             ent.Comp.Actors.Remove(key);
 
-        Dirty(ent);
+        DirtyField(ent, nameof(UserInterfaceComponent.Actors));
 
         // If the actor is also deleting then don't worry about updating what they have open.
         if (!TerminatingOrDeleted(actor)
@@ -256,7 +261,7 @@ public abstract class SharedUserInterfaceSystem : EntitySystem
         // Let state handling open the UI clientside.
         actorComp.OpenInterfaces.GetOrNew(ent.Owner).Add(key);
         ent.Comp.Actors.GetOrNew(key).Add(actor);
-        Dirty(ent);
+        DirtyField(ent, nameof(UserInterfaceComponent.Actors));
 
         var ev = new BoundUIOpenedEvent(key, ent.Owner, actor);
         RaiseLocalEvent(ent.Owner, ev);
@@ -275,6 +280,7 @@ public abstract class SharedUserInterfaceSystem : EntitySystem
             if (ent.Comp.States.TryGetValue(key, out var state))
             {
                 bui.UpdateState(state);
+                bui.Update();
             }
         }
     }
@@ -295,25 +301,54 @@ public abstract class SharedUserInterfaceSystem : EntitySystem
             DebugTools.Assert(!ent.Comp.Actors.ContainsKey(key));
         }
 
-        DebugTools.AssertEqual(ent.Comp.ClientOpenInterfaces.Count, 0);
+        DebugTools.Assert(ent.Comp.ClientOpenInterfaces.Values.All(x => _queuedCloses.Contains(x)));
     }
 
     private void OnUserInterfaceGetState(Entity<UserInterfaceComponent> ent, ref ComponentGetState args)
     {
-        // TODO delta states.
-        // I.e., don't resend the whole BUI state just because a new user opened it.
+        if (ent.Comp.LastFieldUpdate >= args.FromTick)
+        {
+            var fields = EntityManager.GetModifiedFields(ent.Comp, args.FromTick);
+
+            switch (fields)
+            {
+                case 1 << 0:
+                {
+                    var state = new UserInterfaceActorsDeltaState();
+                    AddActors(ent, state.Actors, ref args);
+
+                    args.State = state;
+                    return;
+                }
+                case 1 << 2:
+                {
+                    var state = new UserInterfaceStatesDeltaState()
+                    {
+                        States = new Dictionary<Enum, BoundUserInterfaceState>(ent.Comp.States),
+                    };
+
+                    args.State = state;
+                    return;
+                }
+            }
+        }
 
         var actors = new Dictionary<Enum, List<NetEntity>>();
-
-        var dataCopy = new Dictionary<Enum, InterfaceData>();
+        var dataCopy = new Dictionary<Enum, InterfaceData>(ent.Comp.Interfaces.Count);
 
         foreach (var (weh, a) in ent.Comp.Interfaces)
         {
             dataCopy[weh] = new InterfaceData(a);
         }
 
-        args.State = new UserInterfaceComponent.UserInterfaceComponentState(actors, ent.Comp.States, dataCopy);
+        args.State = new UserInterfaceComponentState(actors, new(ent.Comp.States), dataCopy);
 
+        // Ensure that only the player that currently has the UI open gets to know what they have it open.
+        AddActors(ent, actors, ref args);
+    }
+
+    private void AddActors(Entity<UserInterfaceComponent> ent, Dictionary<Enum, List<NetEntity>> actors, ref ComponentGetState args)
+    {
         // Ensure that only the player that currently has the UI open gets to know what they have it open.
         if (args.ReplayState)
         {
@@ -335,106 +370,140 @@ public abstract class SharedUserInterfaceSystem : EntitySystem
 
     private void OnUserInterfaceHandleState(Entity<UserInterfaceComponent> ent, ref ComponentHandleState args)
     {
-        if (args.Current is not UserInterfaceComponent.UserInterfaceComponentState state)
+        Dictionary<Enum, List<NetEntity>>? stateActors = null;
+        Dictionary<Enum, InterfaceData>? stateData = null;
+        Dictionary<Enum, BoundUserInterfaceState>? stateStates = null;
+
+        if (args.Current is UserInterfaceComponentState state)
+        {
+            stateActors = state.Actors;
+            stateData = state.Data;
+            stateStates = state.States;
+        }
+        else if (args.Current is UserInterfaceActorsDeltaState actorDelta)
+        {
+            stateActors = actorDelta.Actors;
+        }
+        else if (args.Current is UserInterfaceStatesDeltaState stateDelta)
+        {
+            stateStates = stateDelta.States;
+        }
+        else
+        {
             return;
-
-        ent.Comp.Interfaces.Clear();
-
-        foreach (var data in state.Data)
-        {
-            ent.Comp.Interfaces[data.Key] = new(data.Value);
         }
 
-        foreach (var key in ent.Comp.Actors.Keys)
+        // Interfaces
+        if (stateData != null)
         {
-            if (!state.Actors.ContainsKey(key))
-                CloseUi(ent!, key);
-        }
+            ent.Comp.Interfaces.Clear();
 
-        var toRemoveActors = new ValueList<EntityUid>();
-        var newSet = new HashSet<EntityUid>();
-        foreach (var (key, stateActors) in state.Actors)
-        {
-            var actors = ent.Comp.Actors.GetOrNew(key);
-
-            newSet.Clear();
-            foreach (var netEntity in stateActors)
+            foreach (var data in stateData)
             {
-                var uid = EnsureEntity<UserInterfaceComponent>(netEntity, ent.Owner);
-                if (uid.IsValid())
-                    newSet.Add(uid);
+                ent.Comp.Interfaces[data.Key] = new(data.Value);
             }
-
-            foreach (var actor in newSet)
-            {
-                if (!actors.Contains(actor))
-                    OpenUiInternal(ent!, key,  actor);
-            }
-
-            foreach (var actor in actors)
-            {
-                if (!newSet.Contains(actor))
-                    toRemoveActors.Add(actor);
-            }
-
-            foreach (var actor in toRemoveActors)
-            {
-                CloseUiInternal(ent!, key, actor);
-            }
-        }
-
-        foreach (var key in ent.Comp.States.Keys)
-        {
-            if (!state.States.ContainsKey(key))
-                ent.Comp.States.Remove(key);
         }
 
         var attachedEnt = Player.LocalEntity;
-        var clientBuis = new ValueList<Enum>(ent.Comp.ClientOpenInterfaces.Keys);
 
-        // Check if the UI is open by us, otherwise dispose of it.
-        foreach (var key in clientBuis)
+        // Actors
+        if (stateActors != null)
         {
-            if (ent.Comp.Actors.TryGetValue(key, out var actors) &&
-                (attachedEnt == null || actors.Contains(attachedEnt.Value)))
+            foreach (var key in ent.Comp.Actors.Keys)
             {
-                continue;
+                if (!stateActors.ContainsKey(key))
+                    CloseUi(ent!, key);
             }
 
-            var bui = ent.Comp.ClientOpenInterfaces[key];
-
-            if (bui.DeferredClose)
-                _queuedCloses.Add(bui);
-            else
+            var toRemoveActors = new ValueList<EntityUid>();
+            var newSet = new HashSet<EntityUid>();
+            foreach (var (key, acts) in stateActors)
             {
-                ent.Comp.ClientOpenInterfaces.Remove(key);
-                bui.Dispose();
+                var actors = ent.Comp.Actors.GetOrNew(key);
+
+                newSet.Clear();
+                foreach (var netEntity in acts)
+                {
+                    var uid = EnsureEntity<UserInterfaceComponent>(netEntity, ent.Owner);
+                    if (uid.IsValid())
+                        newSet.Add(uid);
+                }
+
+                foreach (var actor in newSet)
+                {
+                    if (!actors.Contains(actor))
+                        OpenUiInternal(ent!, key,  actor);
+                }
+
+                foreach (var actor in actors)
+                {
+                    if (!newSet.Contains(actor))
+                        toRemoveActors.Add(actor);
+                }
+
+                foreach (var actor in toRemoveActors)
+                {
+                    CloseUiInternal(ent!, key, actor);
+                }
+            }
+
+            var clientBuis = new ValueList<Enum>(ent.Comp.ClientOpenInterfaces.Keys);
+
+            // Check if the UI is open by us, otherwise dispose of it.
+            foreach (var key in clientBuis)
+            {
+                if (ent.Comp.Actors.TryGetValue(key, out var actors) &&
+                    (attachedEnt == null || actors.Contains(attachedEnt.Value)))
+                {
+                    continue;
+                }
+
+                var bui = ent.Comp.ClientOpenInterfaces[key];
+
+                if (bui.DeferredClose)
+                    _queuedCloses.Add(bui);
+                else
+                {
+                    ent.Comp.ClientOpenInterfaces.Remove(key);
+                    bui.Dispose();
+                }
             }
         }
 
-        // update any states we have open
-        foreach (var (key, buiState) in state.States)
+        // States
+        if (stateStates != null)
         {
-            if (ent.Comp.States.TryGetValue(key, out var existing) &&
-                existing.Equals(buiState))
+            foreach (var key in ent.Comp.States.Keys)
             {
-                continue;
+                if (!stateStates.ContainsKey(key))
+                    ent.Comp.States.Remove(key);
             }
 
-            ent.Comp.States[key] = buiState;
+            // update any states we have open
+            foreach (var (key, buiState) in stateStates)
+            {
+                if (ent.Comp.States.TryGetValue(key, out var existing) &&
+                    existing.Equals(buiState))
+                {
+                    continue;
+                }
 
-            if (!ent.Comp.ClientOpenInterfaces.TryGetValue(key, out var cBui))
-                continue;
+                ent.Comp.States[key] = buiState;
 
-            cBui.State = buiState;
-            cBui.UpdateState(buiState);
+                if (!ent.Comp.ClientOpenInterfaces.TryGetValue(key, out var cBui))
+                    continue;
+
+                cBui.State = buiState;
+                cBui.UpdateState(buiState);
+                cBui.Update();
+            }
         }
 
         // If UI not open then open it
         // If we get the first state for an ent coming in then don't open BUIs yet, just defer it until later.
         var open = ent.Comp.LifeStage > ComponentLifeStage.Added;
 
-        if (attachedEnt != null)
+        if (attachedEnt != null && stateActors != null)
         {
             foreach (var (key, value) in ent.Comp.Interfaces)
             {
@@ -490,6 +559,7 @@ public abstract class SharedUserInterfaceSystem : EntitySystem
         {
             boundUserInterface.State = buiState;
             boundUserInterface.UpdateState(buiState);
+            boundUserInterface.Update();
         }
 #if EXCEPTION_TOLERANCE
         }
@@ -669,7 +739,7 @@ public abstract class SharedUserInterfaceSystem : EntitySystem
             if (!entity.Comp.States.Remove(key))
                 return;
 
-            Dirty(entity);
+            DirtyField(entity, nameof(UserInterfaceComponent.States));
         }
         // Non-null state, check if it matches existing.
         else
@@ -682,7 +752,14 @@ public abstract class SharedUserInterfaceSystem : EntitySystem
             stateRef = state;
         }
 
-        Dirty(entity);
+        // Predict the change on client
+        if (state != null && _netManager.IsClient && entity.Comp.ClientOpenInterfaces.TryGetValue(key, out var bui))
+        {
+            bui.UpdateState(state);
+            bui.Update();
+        }
+
+        DirtyField(entity, nameof(UserInterfaceComponent.States));
     }
 
     /// <summary>
@@ -1024,7 +1101,19 @@ public abstract class SharedUserInterfaceSystem : EntitySystem
             ent.Comp = AddComp<UserInterfaceComponent>(ent);
 
         ent.Comp.Interfaces[key] = data;
-        Dirty(ent, ent.Comp);
+        DirtyField(ent, nameof(UserInterfaceComponent.Interfaces));
+    }
+
+    public bool TryGetUiState<T>(Entity<UserInterfaceComponent?> ent, Enum key, [NotNullWhen(true)] out T? state) where T : BoundUserInterfaceState
+    {
+        if (!Resolve(ent, ref ent.Comp, false) || !ent.Comp.States.TryGetValue(key, out var stateComp))
+        {
+            state = null;
+            return false;
+        }
+
+        state = (T)stateComp;
+        return true;
     }
 
     /// <summary>

Robust.Shared/Map/Events/MapSerializationEvents.cs

@@ -28,24 +28,17 @@ public sealed class BeforeEntityReadEvent
 }
 
 /// <summary>
-/// This event is broadcast just before the map loader reads the entity section. It can be used to somewhat modify
-/// how the map data is read, as a super basic kind of map migration tool.
+/// This event is broadcast just before an entity gets serialized.
 /// </summary>
-public sealed class BeforeSaveEvent
+public sealed class BeforeSaveEvent(EntityUid entity, EntityUid? map)
 {
     /// <summary>
     /// The entity that is going to be saved. usually a map or grid.
     /// </summary>
-    public EntityUid Entity;
+    public EntityUid Entity = entity;
 
     /// <summary>
     /// The map that the <see cref="Entity"/> is on.
     /// </summary>
-    public EntityUid? Map;
-
-    public BeforeSaveEvent(EntityUid entity, EntityUid? map)
-    {
-        Entity = entity;
-        Map = map;
-    }
+    public EntityUid? Map = map;
 }

Robust.Shared/Noise/FastNoise.cs

@@ -41,10 +41,8 @@ using System.Runtime.CompilerServices;
 
 namespace Robust.Shared.Noise
 {
-#pragma warning disable RA0003
     [Obsolete("Use FastNoiseLite")]
     public sealed class FastNoise
-#pragma warning restore RA0003
     {
         private const MethodImplOptions FN_INLINE = MethodImplOptions.AggressiveInlining;
         private const int FN_CELLULAR_INDEX_MAX = 3;

Robust.Shared/Physics/B2DynamicTree.cs

@@ -27,6 +27,7 @@ using System.Diagnostics.CodeAnalysis;
 using System.Numerics;
 using System.Runtime.CompilerServices;
 using Robust.Shared.Maths;
+using Robust.Shared.Physics.Systems;
 using Robust.Shared.Utility;
 
 namespace Robust.Shared.Physics
@@ -943,6 +944,217 @@ namespace Robust.Shared.Physics
         private static readonly RayQueryCallback<RayQueryCallback> EasyRayQueryCallback =
             (ref RayQueryCallback callback, Proxy proxy, in Vector2 hitPos, float distance) => callback(proxy, hitPos, distance);
 
+        internal delegate float RayCallback(RayCastInput input, T context, ref WorldRayCastContext state);
+
+        internal void RayCastNew(RayCastInput input, long mask, ref WorldRayCastContext state, RayCallback callback)
+        {
+            var p1 = input.Origin;
+            var d = input.Translation;
+
+            var r = d.Normalized();
+
+	        // v is perpendicular to the segment.
+	        var v = Vector2Helpers.Cross(1.0f, r);
+            var abs_v = Vector2.Abs(v);
+
+	        // Separating axis for segment (Gino, p80).
+	        // |dot(v, p1 - c)| > dot(|v|, h)
+
+	        float maxFraction = input.MaxFraction;
+
+	        var p2 = Vector2.Add(p1, maxFraction * d);
+
+	        // Build a bounding box for the segment.
+	        var segmentAABB = new Box2(Vector2.Min(p1, p2), Vector2.Max(p1, p2));
+
+	        var stack = new GrowableStack<Proxy>(stackalloc Proxy[256]);
+            ref var baseRef = ref _nodes[0];
+	        stack.Push(_root);
+
+	        var subInput = input;
+
+	        while (stack.GetCount() > 0)
+            {
+                var nodeId = stack.Pop();
+
+		        if (nodeId == Proxy.Free)
+		        {
+			        continue;
+		        }
+
+		        var node = Unsafe.Add(ref baseRef, nodeId);
+
+		        if (!node.Aabb.Intersects(segmentAABB))// || ( node->categoryBits & maskBits ) == 0 )
+		        {
+			        continue;
+		        }
+
+		        // Separating axis for segment (Gino, p80).
+		        // |dot(v, p1 - c)| > dot(|v|, h)
+		        // radius extension is added to the node in this case
+		        var c = node.Aabb.Center;
+		        var h = node.Aabb.Extents;
+		        float term1 = MathF.Abs(Vector2.Dot(v, Vector2.Subtract(p1, c)));
+		        float term2 = Vector2.Dot(abs_v, h);
+		        if ( term2 < term1 )
+		        {
+			        continue;
+		        }
+
+		        if (node.IsLeaf)
+		        {
+			        subInput.MaxFraction = maxFraction;
+
+			        float value = callback(subInput, node.UserData, ref state);
+
+			        if (value == 0.0f)
+			        {
+				        // The client has terminated the ray cast.
+				        return;
+			        }
+
+			        if (0.0f < value && value < maxFraction)
+			        {
+				        // Update segment bounding box.
+				        maxFraction = value;
+				        p2 = Vector2.Add(p1, maxFraction * d);
+				        segmentAABB.BottomLeft = Vector2.Min( p1, p2 );
+				        segmentAABB.TopRight = Vector2.Max( p1, p2 );
+			        }
+		        }
+		        else
+                {
+                    var stackCount = stack.GetCount();
+			        Assert( stackCount < 256 - 1 );
+			        if (stackCount < 256 - 1 )
+			        {
+				        // TODO_ERIN just put one node on the stack, continue on a child node
+				        // TODO_ERIN test ordering children by nearest to ray origin
+				        stack.Push(node.Child1);
+				        stack.Push(node.Child2);
+			        }
+		        }
+	        }
+        }
+
+        /// This function receives clipped ray-cast input for a proxy. The function
+        /// returns the new ray fraction.
+        /// - return a value of 0 to terminate the ray-cast
+        /// - return a value less than input->maxFraction to clip the ray
+        /// - return a value of input->maxFraction to continue the ray cast without clipping
+        internal delegate float TreeShapeCastCallback(ShapeCastInput input, T userData, ref WorldRayCastContext state);
+
+        internal void ShapeCast(ShapeCastInput input, long maskBits, TreeShapeCastCallback callback, ref WorldRayCastContext state)
+        {
+	        if (input.Count == 0)
+	        {
+		        return;
+	        }
+
+            var originAABB = new Box2(input.Points[0], input.Points[0]);
+
+	        for (var i = 1; i < input.Count; ++i)
+	        {
+		        originAABB.BottomLeft = Vector2.Min(originAABB.BottomLeft, input.Points[i]);
+		        originAABB.TopRight = Vector2.Max(originAABB.TopRight, input.Points[i]);
+	        }
+
+	        var radius = new Vector2(input.Radius, input.Radius);
+
+	        originAABB.BottomLeft = Vector2.Subtract(originAABB.BottomLeft, radius);
+	        originAABB.TopRight = Vector2.Add(originAABB.TopRight, radius );
+
+	        var p1 = originAABB.Center;
+	        var extension = originAABB.Extents;
+
+	        // v is perpendicular to the segment.
+	        var r = input.Translation;
+	        var v = Vector2Helpers.Cross(1.0f, r);
+	        var abs_v = Vector2.Abs(v);
+
+	        // Separating axis for segment (Gino, p80).
+	        // |dot(v, p1 - c)| > dot(|v|, h)
+
+	        float maxFraction = input.MaxFraction;
+
+	        // Build total box for the shape cast
+	        var t = Vector2.Multiply(maxFraction, input.Translation);
+
+            var totalAABB = new Box2(
+		        Vector2.Min(originAABB.BottomLeft, Vector2.Add(originAABB.BottomLeft, t)),
+		        Vector2.Max(originAABB.TopRight, Vector2.Add( originAABB.TopRight, t))
+	        );
+
+	        var subInput = input;
+
+            ref var baseRef = ref _nodes[0];
+            var stack = new GrowableStack<Proxy>(stackalloc Proxy[256]);
+	        stack.Push(_root);
+
+	        while (stack.GetCount() > 0)
+            {
+		        var nodeId = stack.Pop();
+
+		        if (nodeId == Proxy.Free)
+		        {
+			        continue;
+		        }
+
+                var node = Unsafe.Add(ref baseRef, nodeId);
+		        if (!node.Aabb.Intersects(totalAABB))// || ( node->categoryBits & maskBits ) == 0 )
+		        {
+			        continue;
+		        }
+
+		        // Separating axis for segment (Gino, p80).
+		        // |dot(v, p1 - c)| > dot(|v|, h)
+		        // radius extension is added to the node in this case
+		        var c = node.Aabb.Center;
+		        var h = Vector2.Add(node.Aabb.Extents, extension);
+		        float term1 = MathF.Abs(Vector2.Dot(v, Vector2.Subtract(p1, c)));
+		        float term2 = Vector2.Dot(abs_v, h);
+		        if (term2 < term1)
+		        {
+			        continue;
+		        }
+
+		        if (node.IsLeaf)
+		        {
+			        subInput.MaxFraction = maxFraction;
+
+			        float value = callback(subInput, node.UserData, ref state);
+
+			        if ( value == 0.0f )
+			        {
+				        // The client has terminated the ray cast.
+				        return;
+			        }
+
+			        if (0.0f < value && value < maxFraction)
+			        {
+				        // Update segment bounding box.
+				        maxFraction = value;
+				        t = Vector2.Multiply(maxFraction, input.Translation);
+				        totalAABB.BottomLeft = Vector2.Min( originAABB.BottomLeft, Vector2.Add(originAABB.BottomLeft, t));
+				        totalAABB.TopRight = Vector2.Max( originAABB.TopRight, Vector2.Add( originAABB.TopRight, t));
+			        }
+		        }
+		        else
+		        {
+                    var stackCount = stack.GetCount();
+			        Assert(stackCount < 256 - 1);
+
+			        if (stackCount < 255)
+			        {
+				        // TODO_ERIN just put one node on the stack, continue on a child node
+				        // TODO_ERIN test ordering children by nearest to ray origin
+				        stack.Push(node.Child1);
+				        stack.Push(node.Child2);
+			        }
+		        }
+	        }
+        }
+
         public void RayCast(RayQueryCallback callback, in Ray input)
         {
             RayCast(ref callback, EasyRayQueryCallback, input);

Robust.Shared/Physics/BroadPhase/DynamicTreeBroadPhase.cs

@@ -24,6 +24,7 @@ public sealed class DynamicTreeBroadPhase : IBroadPhase
     }
 
     public int Count => _tree.NodeCount;
+    public B2DynamicTree<FixtureProxy> Tree => _tree;
 
     public Box2 GetFatAabb(DynamicTree.Proxy proxy)
     {

Robust.Shared/Physics/Collision/DistanceProxy.cs

@@ -45,6 +45,12 @@ internal ref struct DistanceProxy
 
     // GJK using Voronoi regions (Christer Ericson) and Barycentric coordinates.
 
+    internal DistanceProxy(Vector2[] vertices, float radius)
+    {
+        Vertices = vertices;
+        Radius = radius;
+    }
+
     /// <summary>
     /// Initialize the proxy using the given shape. The shape
     /// must remain in scope while the proxy is in use.
@@ -143,6 +149,13 @@ internal ref struct DistanceProxy
 
         return Vertices[bestIndex];
     }
+
+    internal static DistanceProxy MakeProxy(Vector2[] vertices, int count, float radius )
+    {
+        count = Math.Min(count, PhysicsConstants.MaxPolygonVertices);
+        var proxy = new DistanceProxy(vertices[..count], radius);
+        return proxy;
+    }
 }
 
 /// <summary>
@@ -306,6 +319,16 @@ internal struct Simplex
         }
     }
 
+    public static Vector2 Weight2( float a1, Vector2 w1, float a2, Vector2 w2 )
+    {
+        return new Vector2(a1 * w1.X + a2 * w2.X, a1 * w1.Y + a2 * w2.Y);
+    }
+
+    public static Vector2 Weight3(float a1, Vector2 w1, float a2, Vector2 w2, float a3, Vector2 w3 )
+    {
+        return new Vector2(a1 * w1.X + a2 * w2.X + a3 * w3.X, a1 * w1.Y + a2 * w2.Y + a3 * w3.Y);
+    }
+
     internal Vector2 GetClosestPoint()
     {
         switch (Count)
@@ -329,6 +352,226 @@ internal struct Simplex
         }
     }
 
+    public static Vector2 ComputeSimplexClosestPoint(Simplex s)
+    {
+        switch (s.Count)
+        {
+            case 0:
+                DebugTools.Assert(false);
+                return Vector2.Zero;
+
+            case 1:
+                return s.V._00.W;
+
+            case 2:
+                return Weight2(s.V._00.A, s.V._00.W, s.V._01.A, s.V._01.W);
+
+            case 3:
+                return Vector2.Zero;
+
+            default:
+                DebugTools.Assert(false);
+                return Vector2.Zero;
+        }
+    }
+
+    public static void ComputeSimplexWitnessPoints(ref Vector2 a, ref Vector2 b, Simplex s)
+    {
+        switch (s.Count)
+        {
+            case 0:
+                DebugTools.Assert(false);
+                break;
+
+            case 1:
+                a = s.V._00.WA;
+                b = s.V._00.WB;
+                break;
+
+            case 2:
+                a = Weight2(s.V._00.A, s.V._00.WA, s.V._01.A, s.V._01.WA);
+                b = Weight2(s.V._00.A, s.V._00.WB, s.V._01.A, s.V._01.WB);
+                break;
+
+            case 3:
+                a = Weight3(s.V._00.A, s.V._00.WA, s.V._01.A, s.V._01.WA, s.V._02.A, s.V._02.WA);
+                // TODO_ERIN why are these not equal?
+                //*b = b2Weight3(s->v1.a, s->v1.wB, s->v2.a, s->v2.wB, s->v3.a, s->v3.wB);
+                b = a;
+                break;
+
+            default:
+                DebugTools.Assert(false);
+                break;
+        }
+    }
+
+    // Solve a line segment using barycentric coordinates.
+    //
+    // p = a1 * w1 + a2 * w2
+    // a1 + a2 = 1
+    //
+    // The vector from the origin to the closest point on the line is
+    // perpendicular to the line.
+    // e12 = w2 - w1
+    // dot(p, e) = 0
+    // a1 * dot(w1, e) + a2 * dot(w2, e) = 0
+    //
+    // 2-by-2 linear system
+    // [1      1     ][a1] = [1]
+    // [w1.e12 w2.e12][a2] = [0]
+    //
+    // Define
+    // d12_1 =  dot(w2, e12)
+    // d12_2 = -dot(w1, e12)
+    // d12 = d12_1 + d12_2
+    //
+    // Solution
+    // a1 = d12_1 / d12
+    // a2 = d12_2 / d12
+    public static void SolveSimplex2(ref Simplex s)
+    {
+	    var w1 = s.V._00.W;
+	    var w2 = s.V._01.W;
+	    var e12 = Vector2.Subtract(w2, w1);
+
+	    // w1 region
+	    float d12_2 = -Vector2.Dot(w1, e12);
+	    if (d12_2 <= 0.0f)
+	    {
+		    // a2 <= 0, so we clamp it to 0
+		    s.V._00.A = 1.0f;
+		    s.Count = 1;
+		    return;
+	    }
+
+	    // w2 region
+	    float d12_1 = Vector2.Dot(w2, e12);
+	    if (d12_1 <= 0.0f)
+	    {
+		    // a1 <= 0, so we clamp it to 0
+		    s.V._01.A = 1.0f;
+		    s.Count = 1;
+		    s.V._00 = s.V._01;
+		    return;
+	    }
+
+	    // Must be in e12 region.
+	    float inv_d12 = 1.0f / ( d12_1 + d12_2 );
+	    s.V._00.A = d12_1 * inv_d12;
+	    s.V._01.A = d12_2 * inv_d12;
+	    s.Count = 2;
+    }
+
+    public static void SolveSimplex3(ref Simplex s)
+    {
+	    var w1 = s.V._00.W;
+        var w2 = s.V._01.W;
+        var w3 = s.V._02.W;
+
+	    // Edge12
+	    // [1      1     ][a1] = [1]
+	    // [w1.e12 w2.e12][a2] = [0]
+	    // a3 = 0
+	    var e12 = Vector2.Subtract(w2, w1);
+	    float w1e12 = Vector2.Dot(w1, e12);
+	    float w2e12 = Vector2.Dot(w2, e12);
+	    float d12_1 = w2e12;
+	    float d12_2 = -w1e12;
+
+	    // Edge13
+	    // [1      1     ][a1] = [1]
+	    // [w1.e13 w3.e13][a3] = [0]
+	    // a2 = 0
+	    var e13 = Vector2.Subtract(w3, w1);
+	    float w1e13 = Vector2.Dot(w1, e13);
+	    float w3e13 = Vector2.Dot(w3, e13);
+	    float d13_1 = w3e13;
+	    float d13_2 = -w1e13;
+
+	    // Edge23
+	    // [1      1     ][a2] = [1]
+	    // [w2.e23 w3.e23][a3] = [0]
+	    // a1 = 0
+	    var e23 = Vector2.Subtract(w3, w2);
+	    float w2e23 = Vector2.Dot(w2, e23);
+	    float w3e23 = Vector2.Dot(w3, e23);
+	    float d23_1 = w3e23;
+	    float d23_2 = -w2e23;
+
+	    // Triangle123
+	    float n123 = Vector2Helpers.Cross(e12, e13);
+
+	    float d123_1 = n123 * Vector2Helpers.Cross(w2, w3);
+	    float d123_2 = n123 * Vector2Helpers.Cross(w3, w1);
+	    float d123_3 = n123 * Vector2Helpers.Cross(w1, w2);
+
+	    // w1 region
+	    if (d12_2 <= 0.0f && d13_2 <= 0.0f)
+	    {
+		    s.V._00.A = 1.0f;
+		    s.Count = 1;
+		    return;
+	    }
+
+	    // e12
+	    if (d12_1 > 0.0f && d12_2 > 0.0f && d123_3 <= 0.0f)
+	    {
+		    float inv_d12 = 1.0f / ( d12_1 + d12_2 );
+		    s.V._00.A = d12_1 * inv_d12;
+		    s.V._01.A = d12_2 * inv_d12;
+		    s.Count = 2;
+		    return;
+	    }
+
+	    // e13
+	    if (d13_1 > 0.0f && d13_2 > 0.0f && d123_2 <= 0.0f)
+	    {
+		    float inv_d13 = 1.0f / ( d13_1 + d13_2 );
+		    s.V._00.A = d13_1 * inv_d13;
+		    s.V._02.A = d13_2 * inv_d13;
+		    s.Count = 2;
+		    s.V._01 = s.V._02;
+		    return;
+	    }
+
+	    // w2 region
+	    if (d12_1 <= 0.0f && d23_2 <= 0.0f)
+	    {
+		    s.V._01.A = 1.0f;
+		    s.Count = 1;
+		    s.V._00 = s.V._01;
+		    return;
+	    }
+
+	    // w3 region
+	    if (d13_1 <= 0.0f && d23_1 <= 0.0f)
+	    {
+		    s.V._02.A = 1.0f;
+		    s.Count = 1;
+		    s.V._00 = s.V._02;
+		    return;
+	    }
+
+	    // e23
+	    if (d23_1 > 0.0f && d23_2 > 0.0f && d123_1 <= 0.0f)
+	    {
+		    float inv_d23 = 1.0f / ( d23_1 + d23_2 );
+		    s.V._01.A = d23_1 * inv_d23;
+		    s.V._02.A = d23_2 * inv_d23;
+		    s.Count = 2;
+		    s.V._00 = s.V._02;
+		    return;
+	    }
+
+	    // Must be in triangle123
+	    float inv_d123 = 1.0f / (d123_1 + d123_2 + d123_3);
+	    s.V._00.A = d123_1 * inv_d123;
+	    s.V._01.A = d123_2 * inv_d123;
+	    s.V._02.A = d123_3 * inv_d123;
+	    s.Count = 3;
+    }
+
     internal void GetWitnessPoints(out Vector2 pA, out Vector2 pB)
     {
         switch (Count)

Robust.Shared/Physics/Collision/Shapes/PolygonShape.cs

@@ -27,6 +27,7 @@ using System.Runtime.InteropServices;
 using Robust.Shared.Configuration;
 using Robust.Shared.IoC;
 using Robust.Shared.Maths;
+using Robust.Shared.Physics.Shapes;
 using Robust.Shared.Physics.Systems;
 using Robust.Shared.Serialization;
 using Robust.Shared.Serialization.Manager.Attributes;
@@ -172,6 +173,13 @@ namespace Robust.Shared.Physics.Collision.Shapes
         {
         }
 
+        internal PolygonShape(Polygon poly)
+        {
+            Vertices = poly.Vertices;
+            Normals = poly.Normals;
+            Centroid = poly.Centroid;
+        }
+
         public PolygonShape(float radius)
         {
             Radius = radius;

Robust.Shared/Physics/Components/PhysicsComponent.Physics.cs

@@ -30,13 +30,17 @@ using Robust.Shared.Maths;
 using Robust.Shared.Physics.Dynamics.Contacts;
 using Robust.Shared.Physics.Systems;
 using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.Timing;
 using Robust.Shared.ViewVariables;
 
 namespace Robust.Shared.Physics.Components;
 
 [RegisterComponent, NetworkedComponent]
-public sealed partial class PhysicsComponent : Component
+public sealed partial class PhysicsComponent : Component, IComponentDelta
 {
+    public GameTick LastFieldUpdate { get; set; }
+    public GameTick[] LastModifiedFields { get; set; }
+
     /// <summary>
     ///     Has this body been added to an island previously in this tick.
     /// </summary>
@@ -57,10 +61,10 @@ public sealed partial class PhysicsComponent : Component
     /// </summary>
     internal readonly LinkedList<Contact> Contacts = new();
 
-    [DataField("ignorePaused"), ViewVariables(VVAccess.ReadWrite)]
+    [DataField]
     public bool IgnorePaused;
 
-    [DataField("bodyType"), Access(typeof(SharedPhysicsSystem), Friend = AccessPermissions.ReadWriteExecute, Other = AccessPermissions.Read)]
+    [DataField, Access(typeof(SharedPhysicsSystem), Friend = AccessPermissions.ReadWriteExecute, Other = AccessPermissions.Read)]
     public BodyType BodyType = BodyType.Static;
 
     // We'll also block Static bodies from ever being awake given they don't need to move.
@@ -74,13 +78,11 @@ public sealed partial class PhysicsComponent : Component
     /// body will be woken.
     /// </summary>
     /// <value><c>true</c> if sleeping is allowed; otherwise, <c>false</c>.</value>
-    [ViewVariables(VVAccess.ReadWrite), DataField("sleepingAllowed"),
-     Access(typeof(SharedPhysicsSystem), Friend = AccessPermissions.ReadWriteExecute,
+    [DataField, Access(typeof(SharedPhysicsSystem), Friend = AccessPermissions.ReadWriteExecute,
          Other = AccessPermissions.Read)]
     public bool SleepingAllowed = true;
 
-    [ViewVariables(VVAccess.ReadWrite), DataField("sleepTime"),
-     Access(typeof(SharedPhysicsSystem), Friend = AccessPermissions.ReadWriteExecute,
+    [DataField, Access(typeof(SharedPhysicsSystem), Friend = AccessPermissions.ReadWriteExecute,
          Other = AccessPermissions.Read)]
     public float SleepTime = 0f;
 
@@ -90,8 +92,7 @@ public sealed partial class PhysicsComponent : Component
     /// <remarks>
     ///     Also known as Enabled in Box2D
     /// </remarks>
-    [ViewVariables(VVAccess.ReadWrite), DataField("canCollide"),
-     Access(typeof(SharedPhysicsSystem), Friend = AccessPermissions.ReadWriteExecute,
+    [DataField, Access(typeof(SharedPhysicsSystem), Friend = AccessPermissions.ReadWriteExecute,
          Other = AccessPermissions.Read)]
     public bool CanCollide = true;
 
@@ -168,7 +169,7 @@ public sealed partial class PhysicsComponent : Component
     /// <summary>
     ///     Is the body allowed to have angular velocity.
     /// </summary>
-    [ViewVariables(VVAccess.ReadWrite), DataField("fixedRotation"),
+    [ViewVariables(VVAccess.ReadWrite), DataField,
      Access(typeof(SharedPhysicsSystem), Friend = AccessPermissions.ReadWriteExecute, Other = AccessPermissions.Read)]
     public bool FixedRotation = true;
 
@@ -189,7 +190,7 @@ public sealed partial class PhysicsComponent : Component
     /// The force is applied to the center of mass.
     /// https://en.wikipedia.org/wiki/Force
     /// </remarks>
-    [ViewVariables(VVAccess.ReadWrite), DataField("force"),
+    [ViewVariables(VVAccess.ReadWrite), DataField,
      Access(typeof(SharedPhysicsSystem), Friend = AccessPermissions.ReadWriteExecute, Other = AccessPermissions.Read)]
     public Vector2 Force;
 
@@ -200,7 +201,7 @@ public sealed partial class PhysicsComponent : Component
     /// The torque rotates around the Z axis on the object.
     /// https://en.wikipedia.org/wiki/Torque
     /// </remarks>
-    [ViewVariables(VVAccess.ReadWrite), DataField("torque"),
+    [ViewVariables(VVAccess.ReadWrite), DataField,
      Access(typeof(SharedPhysicsSystem), Friend = AccessPermissions.ReadWriteExecute, Other = AccessPermissions.Read)]
     public float Torque;
 
@@ -216,7 +217,7 @@ public sealed partial class PhysicsComponent : Component
     ///     This is a set amount that the body's linear velocity is reduced by every tick.
     ///     Combined with the tile friction.
     /// </summary>
-    [ViewVariables(VVAccess.ReadWrite), DataField("linearDamping"),
+    [DataField,
      Access(typeof(SharedPhysicsSystem), Friend = AccessPermissions.ReadWriteExecute,
          Other = AccessPermissions.Read)]
     public float LinearDamping = 0.2f;
@@ -226,7 +227,7 @@ public sealed partial class PhysicsComponent : Component
     ///     Combined with the tile friction.
     /// </summary>
     /// <returns></returns>
-    [ViewVariables(VVAccess.ReadWrite), DataField("angularDamping"),
+    [DataField,
      Access(typeof(SharedPhysicsSystem), Friend = AccessPermissions.ReadWriteExecute,
          Other = AccessPermissions.Read)]
     public float AngularDamping = 0.2f;
@@ -260,7 +261,7 @@ public sealed partial class PhysicsComponent : Component
     /// <summary>
     ///     The current status of the object
     /// </summary>
-    [ViewVariables(VVAccess.ReadWrite), DataField("bodyStatus"), Access(typeof(SharedPhysicsSystem), Friend = AccessPermissions.ReadWriteExecute, Other = AccessPermissions.Read)]
+    [DataField, Access(typeof(SharedPhysicsSystem), Friend = AccessPermissions.ReadWriteExecute, Other = AccessPermissions.Read)]
     public BodyStatus BodyStatus { get; set; }
 
     [ViewVariables, Access(typeof(SharedPhysicsSystem))]

Robust.Shared/Physics/Components/PhysicsComponentState.cs

@@ -1,35 +1,97 @@
 using System;
+using System.Collections.Generic;
 using System.Numerics;
 using Robust.Shared.GameObjects;
-using Robust.Shared.Maths;
 using Robust.Shared.Serialization;
 
 namespace Robust.Shared.Physics.Components;
 
+/// <summary>
+/// Average use-case of only linear velocity update
+/// </summary>
 [Serializable, NetSerializable]
-public readonly record struct PhysicsComponentState(
-        bool CanCollide,
-        bool SleepingAllowed,
-        bool FixedRotation,
-        BodyStatus Status,
-        Vector2 LinearVelocity,
-        float AngularVelocity,
-        BodyType BodyType,
-        float Friction,
-        float LinearDamping,
-        float AngularDamping)
-    : IComponentState
+public record struct PhysicsLinearVelocityDeltaState : IComponentDeltaState<PhysicsComponentState>
 {
-    public readonly bool CanCollide = CanCollide;
-    public readonly bool SleepingAllowed = SleepingAllowed;
-    public readonly bool FixedRotation = FixedRotation;
-    public readonly BodyStatus Status = Status;
+    public Vector2 LinearVelocity;
 
-    public readonly Vector2 LinearVelocity = LinearVelocity;
-    public readonly float AngularVelocity = AngularVelocity;
-    public readonly BodyType BodyType = BodyType;
+    public void ApplyToFullState(PhysicsComponentState fullState)
+    {
+        fullState.LinearVelocity = LinearVelocity;
+    }
 
-    public readonly float Friction = Friction;
-    public readonly float LinearDamping = LinearDamping;
-    public readonly float AngularDamping = AngularDamping;
+    public PhysicsComponentState CreateNewFullState(PhysicsComponentState fullState)
+    {
+        var copy = new PhysicsComponentState(fullState)
+        {
+            LinearVelocity = LinearVelocity,
+        };
+        return copy;
+    }
+}
+
+/// <summary>
+/// 2nd-most typical usecase of just velocity updates
+/// </summary>
+[Serializable, NetSerializable]
+public record struct PhysicsVelocityDeltaState : IComponentDeltaState<PhysicsComponentState>
+{
+    public Vector2 LinearVelocity;
+    public float AngularVelocity;
+
+    public void ApplyToFullState(PhysicsComponentState fullState)
+    {
+        fullState.LinearVelocity = LinearVelocity;
+        fullState.AngularVelocity = AngularVelocity;
+    }
+
+    public PhysicsComponentState CreateNewFullState(PhysicsComponentState fullState)
+    {
+        var copy = new PhysicsComponentState(fullState)
+        {
+            LinearVelocity = LinearVelocity,
+            AngularVelocity = AngularVelocity
+        };
+        return copy;
+    }
+}
+
+[Serializable, NetSerializable]
+public sealed class PhysicsComponentState : IComponentState
+{
+    public bool CanCollide;
+    public bool SleepingAllowed;
+    public bool FixedRotation;
+    public BodyStatus Status;
+
+    public Vector2 LinearVelocity;
+    public float AngularVelocity;
+    public BodyType BodyType;
+
+    public float Friction;
+    public float LinearDamping;
+    public float AngularDamping;
+
+    public Vector2 Force;
+    public float Torque;
+
+    public PhysicsComponentState() {}
+
+    public PhysicsComponentState(PhysicsComponentState existing)
+    {
+        CanCollide = existing.CanCollide;
+        SleepingAllowed = existing.SleepingAllowed;
+        FixedRotation = existing.FixedRotation;
+        Status = existing.Status;
+
+        LinearVelocity = existing.LinearVelocity;
+        AngularVelocity = existing.AngularVelocity;
+        BodyType = existing.BodyType;
+
+        Friction = existing.Friction;
+        LinearDamping = existing.LinearDamping;
+        AngularDamping = existing.AngularDamping;
+
+        Force = existing.Force;
+        Torque = existing.Torque;
+    }
 }

Robust.Shared/Physics/IBroadPhase.cs

@@ -10,6 +10,8 @@ public interface IBroadPhase
 {
     int Count { get; }
 
+    public B2DynamicTree<FixtureProxy> Tree { get; }
+
     Box2 GetFatAabb(DynamicTree.Proxy proxy);
 
     DynamicTree.Proxy AddProxy(ref FixtureProxy proxy);

Robust.Shared/Physics/Shapes/Polygon.cs

@@ -87,8 +87,8 @@ internal record struct Polygon : IPhysShape
 
         if (hull.Count < 3)
         {
-            Vertices = Array.Empty<Vector2>();
-            Normals = Array.Empty<Vector2>();
+            Vertices = [];
+            Normals = [];
             return;
         }
 

Robust.Shared/Physics/Systems/RayCastSystem.Geometry.cs

@@ -0,0 +1,736 @@
+using System;
+using System.Numerics;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Maths;
+using Robust.Shared.Physics.Collision;
+using Robust.Shared.Physics.Collision.Shapes;
+using Robust.Shared.Physics.Dynamics;
+using Robust.Shared.Physics.Shapes;
+using Robust.Shared.Utility;
+
+namespace Robust.Shared.Physics.Systems;
+
+public sealed partial class RayCastSystem
+{
+    /*
+     * This is really "geometry and friends" as it has all the private methods.
+     */
+
+    #region Callbacks
+
+    /// <summary>
+    /// Returns every entity from the callback.
+    /// </summary>
+    public static float RayCastAllCallback(FixtureProxy proxy, Vector2 point, Vector2 normal, float fraction, ref RayResult result)
+    {
+        result.Results.Add(new RayHit(proxy.Entity, normal, fraction)
+        {
+            Point = point,
+        });
+        return 1f;
+    }
+
+    /// <summary>
+    /// Gets the closest entity from the callback.
+    /// </summary>
+    public static float RayCastClosestCallback(FixtureProxy proxy, Vector2 point, Vector2 normal, float fraction, ref RayResult result)
+    {
+        var add = false;
+
+        if (result.Results.Count > 0)
+        {
+            if (result.Results[0].Fraction > fraction)
+            {
+                add = true;
+                result.Results.Clear();
+            }
+        }
+        else
+        {
+            add = true;
+        }
+
+        if (add)
+        {
+            result.Results.Add(new RayHit(proxy.Entity, normal, fraction)
+            {
+                Point = point,
+            });
+        }
+
+        return fraction;
+    }
+
+    #endregion
+
+    #region Raycast
+
+    private CastOutput RayCastShape(RayCastInput input, IPhysShape shape, Transform transform)
+    {
+        var localInput = input;
+        localInput.Origin = Physics.Transform.InvTransformPoint(transform, input.Origin);
+        localInput.Translation = Quaternion2D.InvRotateVector(transform.Quaternion2D, input.Translation);
+
+        CastOutput output = new();
+
+        switch (shape)
+        {
+            /*
+            case b2_capsuleShape:
+                output = b2RayCastCapsule( &localInput, &shape->capsule );
+                break;
+                */
+            case PhysShapeCircle circle:
+                output = RayCastCircle(localInput, circle);
+                break;
+            case PolygonShape polyShape:
+            {
+                output = RayCastPolygon(localInput, (Polygon) polyShape);
+            }
+                break;
+            case Polygon poly:
+            {
+                output = RayCastPolygon(localInput, poly);
+            }
+                break;
+            default:
+                return output;
+        }
+
+        output.Point = Physics.Transform.Mul(transform, output.Point);
+        output.Normal = Quaternion2D.RotateVector(transform.Quaternion2D, output.Normal);
+        return output;
+    }
+
+    /// <summary>
+    /// This callback is invoked upon every AABB collision.
+    /// </summary>
+    private static float RayCastCallback(RayCastInput input, FixtureProxy proxy, ref WorldRayCastContext worldContext)
+    {
+        if ((proxy.Fixture.CollisionLayer & worldContext.Filter.MaskBits) == 0 && (proxy.Fixture.CollisionMask & worldContext.Filter.LayerBits) == 0)
+        {
+            return input.MaxFraction;
+        }
+
+        if (worldContext.Filter.IsIgnored?.Invoke(proxy.Entity) == true)
+        {
+            return input.MaxFraction;
+        }
+
+        var transform = worldContext.Physics.GetLocalPhysicsTransform(proxy.Entity);
+        var output = worldContext.System.RayCastShape(input, proxy.Fixture.Shape, transform);
+
+        if (output.Hit)
+        {
+            // Fraction returned determines what B2Dynamictree will do, i.e. shrink the AABB or not.
+            var fraction = worldContext.fcn(proxy, output.Point, output.Normal, output.Fraction, ref worldContext.Result);
+            return fraction;
+        }
+
+        return input.MaxFraction;
+    }
+
+    // Precision Improvements for Ray / Sphere Intersection - Ray Tracing Gems 2019
+    // http://www.codercorner.com/blog/?p=321
+    internal CastOutput RayCastCircle(RayCastInput input, PhysShapeCircle shape)
+    {
+        DebugTools.Assert(input.IsValidRay());
+
+        var p = shape.Position;
+
+        var output = new CastOutput();
+
+        // Shift ray so circle center is the origin
+        var s = Vector2.Subtract(input.Origin, p);
+        float length = 0f;
+        var d = input.Translation.GetLengthAndNormalize(ref length);
+        if (length == 0.0f)
+        {
+            // zero length ray
+            return output;
+        }
+
+        // Find closest point on ray to origin
+
+        // solve: dot(s + t * d, d) = 0
+        float t = -Vector2.Dot(s, d);
+
+        // c is the closest point on the line to the origin
+        var c = Vector2.Add(s, t * d);
+
+        float cc = Vector2.Dot(c, c);
+        float r = shape.Radius;
+        float rr = r * r;
+
+        if (cc > rr)
+        {
+            // closest point is outside the circle
+            return output;
+        }
+
+        // Pythagorus
+        float h = MathF.Sqrt(rr - cc);
+
+        float fraction = t - h;
+
+        if ( fraction < 0.0f || input.MaxFraction * length < fraction )
+        {
+            // outside the range of the ray segment
+            return output;
+        }
+
+        var hitPoint = Vector2.Add(s, fraction * d);
+
+        output.Fraction = fraction / length;
+        output.Normal = hitPoint.Normalized();
+        output.Point = Vector2.Add(p, shape.Radius * output.Normal);
+        output.Hit = true;
+
+        return output;
+    }
+
+    private CastOutput RayCastPolygon(RayCastInput input, Polygon shape)
+    {
+	    if (shape.Radius == 0.0f)
+	    {
+		    // Put the ray into the polygon's frame of reference.
+		    var p1 = input.Origin;
+		    var d = input.Translation;
+
+		    float lower = 0.0f, upper = input.MaxFraction;
+
+		    var index = -1;
+
+		    var output = new CastOutput()
+            {
+                Fraction = 0f,
+            };
+
+		    for ( var i = 0; i < shape.VertexCount; ++i )
+		    {
+			    // p = p1 + a * d
+			    // dot(normal, p - v) = 0
+			    // dot(normal, p1 - v) + a * dot(normal, d) = 0
+			    float numerator = Vector2.Dot(shape.Normals[i], Vector2.Subtract( shape.Vertices[i], p1 ) );
+			    float denominator = Vector2.Dot(shape.Normals[i], d );
+
+			    if ( denominator == 0.0f )
+			    {
+				    if ( numerator < 0.0f )
+				    {
+					    return output;
+				    }
+			    }
+			    else
+			    {
+				    // Note: we want this predicate without division:
+				    // lower < numerator / denominator, where denominator < 0
+				    // Since denominator < 0, we have to flip the inequality:
+				    // lower < numerator / denominator <==> denominator * lower > numerator.
+				    if ( denominator < 0.0f && numerator < lower * denominator )
+				    {
+					    // Increase lower.
+					    // The segment enters this half-space.
+					    lower = numerator / denominator;
+					    index = i;
+				    }
+				    else if ( denominator > 0.0f && numerator < upper * denominator )
+				    {
+					    // Decrease upper.
+					    // The segment exits this half-space.
+					    upper = numerator / denominator;
+				    }
+			    }
+
+			    // The use of epsilon here causes the B2_ASSERT on lower to trip
+			    // in some cases. Apparently the use of epsilon was to make edge
+			    // shapes work, but now those are handled separately.
+			    // if (upper < lower - b2_epsilon)
+			    if ( upper < lower )
+			    {
+				    return output;
+			    }
+		    }
+
+		    DebugTools.Assert( 0.0f <= lower && lower <= input.MaxFraction );
+
+		    if (index >= 0)
+		    {
+			    output.Fraction = lower;
+			    output.Normal = shape.Normals[index];
+			    output.Point = Vector2.Add(p1, lower * d);
+			    output.Hit = true;
+		    }
+
+		    return output;
+	    }
+
+	    // TODO_ERIN this is not working for ray vs box (zero radii)
+	    var castInput = new ShapeCastPairInput
+        {
+            ProxyA = DistanceProxy.MakeProxy(shape.Vertices, shape.VertexCount, shape.Radius),
+            ProxyB = DistanceProxy.MakeProxy([input.Origin], 1, 0.0f),
+            TransformA = Physics.Transform.Empty,
+            TransformB = Physics.Transform.Empty,
+            TranslationB = input.Translation,
+            MaxFraction = input.MaxFraction
+        };
+        return ShapeCast(castInput);
+    }
+
+    // Ray vs line segment
+    private CastOutput RayCastSegment(RayCastInput input, EdgeShape shape, bool oneSided)
+    {
+        var output = new CastOutput();
+
+        if (oneSided)
+        {
+            // Skip left-side collision
+            float offset = Vector2Helpers.Cross(Vector2.Subtract(input.Origin, shape.Vertex0), Vector2.Subtract( shape.Vertex1, shape.Vertex0));
+            if ( offset < 0.0f )
+            {
+                return output;
+            }
+        }
+
+        // Put the ray into the edge's frame of reference.
+        var p1 = input.Origin;
+        var d = input.Translation;
+
+        var v1 = shape.Vertex0;
+        var v2 = shape.Vertex1;
+        var e = Vector2.Subtract( v2, v1 );
+
+        float length = 0f;
+        var eUnit = e.GetLengthAndNormalize(ref length);
+        if (length == 0.0f)
+        {
+            return output;
+        }
+
+        // Normal points to the right, looking from v1 towards v2
+        var normal = eUnit.RightPerp();
+
+        // Intersect ray with infinite segment using normal
+        // Similar to intersecting a ray with an infinite plane
+        // p = p1 + t * d
+        // dot(normal, p - v1) = 0
+        // dot(normal, p1 - v1) + t * dot(normal, d) = 0
+        float numerator = Vector2.Dot(normal, Vector2.Subtract(v1, p1));
+        float denominator = Vector2.Dot(normal, d);
+
+        if (denominator == 0.0f)
+        {
+            // parallel
+            return output;
+        }
+
+        float t = numerator / denominator;
+        if ( t < 0.0f || input.MaxFraction < t )
+        {
+            // out of ray range
+            return output;
+        }
+
+        // Intersection point on infinite segment
+        var p = Vector2.Add(p1, t * d);
+
+        // Compute position of p along segment
+        // p = v1 + s * e
+        // s = dot(p - v1, e) / dot(e, e)
+
+        float s = Vector2.Dot(Vector2.Subtract(p, v1), eUnit);
+        if ( s < 0.0f || length < s )
+        {
+            // out of segment range
+            return output;
+        }
+
+        if ( numerator > 0.0f )
+        {
+            normal = -normal;
+        }
+
+        output.Fraction = t;
+        output.Point = Vector2.Add(p1, t * d);
+        output.Normal = normal;
+        output.Hit = true;
+
+        return output;
+    }
+
+    #endregion
+
+    #region Shape
+
+    private CastOutput ShapeCastShape(ShapeCastInput input, IPhysShape shape, Transform transform)
+    {
+        var localInput = input;
+
+        for ( int i = 0; i < localInput.Count; ++i )
+        {
+            localInput.Points[i] = Physics.Transform.MulT(transform, input.Points[i]);
+        }
+
+        localInput.Translation = Quaternion2D.InvRotateVector(transform.Quaternion2D, input.Translation);
+
+        CastOutput output;
+
+        switch (shape)
+        {
+            case PhysShapeCircle circle:
+                output = ShapeCastCircle(localInput, circle);
+                break;
+            case PolygonShape pShape:
+                output = ShapeCastPolygon(localInput, (Polygon) pShape);
+                break;
+            case Polygon poly:
+                output = ShapeCastPolygon(localInput, poly);
+                break;
+            default:
+                return new CastOutput();
+        }
+
+        output.Point = Physics.Transform.Mul(transform, output.Point);
+        output.Normal = Quaternion2D.RotateVector(transform.Quaternion2D, output.Normal);
+        return output;
+    }
+
+    /// <summary>
+    /// This callback is invoked upon getting the AABB inside of B2DynamicTree.
+    /// </summary>
+    /// <returns>The max fraction to continue checking for. If this is lower then we will start dropping more shapes early</returns>
+    private float ShapeCastCallback(ShapeCastInput input, FixtureProxy proxy, ref WorldRayCastContext worldContext)
+    {
+        var filter = worldContext.Filter;
+
+        if ((proxy.Fixture.CollisionLayer & filter.MaskBits) == 0 && (proxy.Fixture.CollisionMask & filter.LayerBits) == 0)
+        {
+            return input.MaxFraction;
+        }
+
+        if ((filter.Flags & QueryFlags.Sensors) == 0x0 && !proxy.Fixture.Hard)
+        {
+            return input.MaxFraction;
+        }
+
+        if (worldContext.Filter.IsIgnored?.Invoke(proxy.Entity) == true)
+        {
+            return input.MaxFraction;
+        }
+
+        var transform = worldContext.Physics.GetLocalPhysicsTransform(proxy.Entity);
+        var output = ShapeCastShape(input, proxy.Fixture.Shape, transform);
+
+        if (output.Hit)
+        {
+            var fraction = worldContext.fcn(proxy, output.Point, output.Normal, output.Fraction, ref worldContext.Result);
+            return fraction;
+        }
+
+        return input.MaxFraction;
+    }
+
+    // GJK-raycast
+    // Algorithm by Gino van den Bergen.
+    // "Smooth Mesh Contacts with GJK" in Game Physics Pearls. 2010
+    // todo this is failing when used to raycast a box
+    // todo this converges slowly with a radius
+    private CastOutput ShapeCast(ShapeCastPairInput input)
+    {
+	    var output = new CastOutput()
+        {
+            Fraction = input.MaxFraction,
+	    };
+
+	    var proxyA = input.ProxyA;
+        var count = input.ProxyB.Vertices.Length;
+
+	    var xfA = input.TransformA;
+	    var xfB = input.TransformB;
+	    var xf = Physics.Transform.InvMulTransforms(xfA, xfB);
+
+	    // Put proxyB in proxyA's frame to reduce round-off error
+        var proxyBVerts = new Vector2[input.ProxyB.Vertices.Length];
+
+	    for ( int i = 0; i < count; ++i )
+	    {
+		    proxyBVerts[i] = Physics.Transform.Mul(xf, input.ProxyB.Vertices[i]);
+	    }
+
+        var proxyB = DistanceProxy.MakeProxy(proxyBVerts, count, input.ProxyB.Radius);
+
+        DebugTools.Assert(proxyB.Vertices.Length <= PhysicsConstants.MaxPolygonVertices);
+	    float radius = proxyA.Radius + proxyB.Radius;
+
+	    var r = Quaternion2D.RotateVector(xf.Quaternion2D, input.TranslationB);
+	    float lambda = 0.0f;
+	    float maxFraction = input.MaxFraction;
+
+	    // Initial simplex
+	    Simplex simplex;
+        simplex = new()
+        {
+            Count = 0,
+            V = new FixedArray4<SimplexVertex>()
+        };
+
+	    // Get an initial point in A - B
+	    int indexA = FindSupport(proxyA, -r);
+	    var wA = proxyA.Vertices[indexA];
+	    int indexB = FindSupport(proxyB, r);
+	    var wB = proxyB.Vertices[indexB];
+	    var v = Vector2.Subtract(wA, wB);
+
+	    // Sigma is the target distance between proxies
+	    const float linearSlop = PhysicsConstants.LinearSlop;
+	    var sigma = MathF.Max(linearSlop, radius - linearSlop);
+
+	    // Main iteration loop.
+	    const int k_maxIters = 20;
+	    int iter = 0;
+	    while ( iter < k_maxIters && v.Length() > sigma + 0.5f * linearSlop )
+	    {
+		    DebugTools.Assert(simplex.Count < 3);
+
+		    output.Iterations += 1;
+
+		    // Support in direction -v (A - B)
+		    indexA = FindSupport(proxyA, -v);
+		    wA = proxyA.Vertices[indexA];
+		    indexB = FindSupport(proxyB, v);
+		    wB = proxyB.Vertices[indexB];
+		    var p = Vector2.Subtract(wA, wB);
+
+		    // -v is a normal at p, normalize to work with sigma
+		    v = v.Normalized();
+
+		    // Intersect ray with plane
+		    float vp = Vector2.Dot(v, p);
+		    float vr = Vector2.Dot(v, r);
+		    if ( vp - sigma > lambda * vr )
+		    {
+			    if ( vr <= 0.0f )
+			    {
+				    // miss
+				    return output;
+			    }
+
+			    lambda = ( vp - sigma ) / vr;
+			    if ( lambda > maxFraction )
+			    {
+				    // too far
+				    return output;
+			    }
+
+			    // reset the simplex
+			    simplex.Count = 0;
+		    }
+
+		    // Reverse simplex since it works with B - A.
+		    // Shift by lambda * r because we want the closest point to the current clip point.
+		    // Note that the support point p is not shifted because we want the plane equation
+		    // to be formed in unshifted space.
+		    ref var vertex = ref simplex.V.AsSpan[simplex.Count];
+		    vertex.IndexA = indexB;
+		    vertex.WA = new Vector2(wB.X + lambda * r.X, wB.Y + lambda * r.Y);
+		    vertex.IndexB = indexA;
+		    vertex.WB = wA;
+		    vertex.W = Vector2.Subtract(vertex.WB, vertex.WA);
+		    vertex.A = 1.0f;
+		    simplex.Count += 1;
+
+		    switch (simplex.Count)
+		    {
+			    case 1:
+				    break;
+
+			    case 2:
+				    Simplex.SolveSimplex2(ref simplex);
+				    break;
+
+			    case 3:
+				    Simplex.SolveSimplex3(ref simplex);
+				    break;
+
+			    default:
+                    throw new NotImplementedException();
+		    }
+
+		    // If we have 3 points, then the origin is in the corresponding triangle.
+		    if ( simplex.Count == 3 )
+		    {
+			    // Overlap
+                // Yes this means you need to manually query for overlaps.
+			    return output;
+		    }
+
+		    // Get search direction.
+		    // todo use more accurate segment perpendicular
+		    v = Simplex.ComputeSimplexClosestPoint(simplex);
+
+		    // Iteration count is equated to the number of support point calls.
+		    ++iter;
+	    }
+
+	    if ( iter == 0 || lambda == 0.0f )
+	    {
+		    // Initial overlap
+		    return output;
+	    }
+
+	    // Prepare output.
+	    Vector2 pointA = Vector2.Zero, pointB = Vector2.Zero;
+	    Simplex.ComputeSimplexWitnessPoints(ref pointB, ref pointA, simplex);
+
+	    var n = (-v).Normalized();
+	    var point = new Vector2(pointA.X + proxyA.Radius * n.X, pointA.Y + proxyA.Radius * n.Y);
+
+	    output.Point = Physics.Transform.Mul(xfA, point);
+	    output.Normal = Quaternion2D.RotateVector(xfA.Quaternion2D, n);
+	    output.Fraction = lambda;
+	    output.Iterations = iter;
+	    output.Hit = true;
+	    return output;
+    }
+
+    private int FindSupport(DistanceProxy proxy, Vector2 direction)
+    {
+        int bestIndex = 0;
+        float bestValue = Vector2.Dot(proxy.Vertices[0], direction);
+        for ( int i = 1; i < proxy.Vertices.Length; ++i )
+        {
+            float value = Vector2.Dot(proxy.Vertices[i], direction);
+            if ( value > bestValue )
+            {
+                bestIndex = i;
+                bestValue = value;
+            }
+        }
+
+        return bestIndex;
+    }
+
+    private CastOutput ShapeCastCircle(ShapeCastInput input, PhysShapeCircle shape)
+    {
+        var pairInput = new ShapeCastPairInput
+        {
+            ProxyA = DistanceProxy.MakeProxy([shape.Position], 1, shape.Radius ),
+            ProxyB = DistanceProxy.MakeProxy(input.Points, input.Count, input.Radius ),
+            TransformA = Physics.Transform.Empty,
+            TransformB = Physics.Transform.Empty,
+            TranslationB = input.Translation,
+            MaxFraction = input.MaxFraction
+        };
+
+        var output = ShapeCast(pairInput);
+        return output;
+    }
+
+    private CastOutput ShapeCastPolygon(ShapeCastInput input, Polygon shape)
+    {
+        var pairInput = new ShapeCastPairInput
+        {
+            ProxyA = DistanceProxy.MakeProxy(shape.Vertices, shape.VertexCount, shape.Radius),
+            ProxyB = DistanceProxy.MakeProxy(input.Points, input.Count, input.Radius),
+            TransformA = Physics.Transform.Empty,
+            TransformB = Physics.Transform.Empty,
+            TranslationB = input.Translation,
+            MaxFraction = input.MaxFraction
+        };
+
+        var output = ShapeCast(pairInput);
+        return output;
+    }
+
+    private CastOutput ShapeCastSegment(ShapeCastInput input, EdgeShape shape)
+    {
+        var pairInput = new ShapeCastPairInput();
+        pairInput.ProxyA = DistanceProxy.MakeProxy([shape.Vertex0], 2, 0.0f);
+        pairInput.ProxyB = DistanceProxy.MakeProxy(input.Points, input.Count, input.Radius);
+        pairInput.TransformA = Physics.Transform.Empty;
+        pairInput.TransformB = Physics.Transform.Empty;
+        pairInput.TranslationB = input.Translation;
+        pairInput.MaxFraction = input.MaxFraction;
+
+        var output = ShapeCast(pairInput);
+        return output;
+    }
+
+    #endregion
+}
+
+internal ref struct WorldRayCastContext
+{
+    public RayCastSystem System;
+    public SharedPhysicsSystem Physics;
+
+    public CastResult fcn;
+    public QueryFilter Filter;
+    public float Fraction;
+
+    public RayResult Result;
+}
+
+internal ref struct ShapeCastPairInput
+{
+    public DistanceProxy ProxyA;
+    public DistanceProxy ProxyB;
+    public Transform TransformA;
+    public Transform TransformB;
+    public Vector2 TranslationB;
+
+    /// <summary>
+    /// The fraction of the translation to consider, typically 1
+    /// </summary>
+    public float MaxFraction;
+}
+
+internal record struct ShapeCastInput
+{
+    public Transform Origin;
+
+    /// A point cloud to cast
+    public Vector2[] Points;
+
+    /// The number of points
+    public int Count;
+
+    /// The radius around the point cloud
+    public float Radius;
+
+    /// The translation of the shape cast
+    public Vector2 Translation;
+
+    /// The maximum fraction of the translation to consider, typically 1
+    public float MaxFraction;
+}
+
+internal record struct RayCastInput
+{
+    public Vector2 Origin;
+
+    public Vector2 Translation;
+
+    public float MaxFraction;
+
+    public bool IsValidRay()
+    {
+        bool isValid = Origin.IsValid() && Translation.IsValid() && MaxFraction.IsValid() &&
+                       0.0f <= MaxFraction && MaxFraction < float.MaxValue;
+        return isValid;
+    }
+}
+
+internal ref struct CastOutput
+{
+    public Vector2 Normal;
+
+    public Vector2 Point;
+
+    public float Fraction;
+
+    public int Iterations;
+
+    public bool Hit;
+}

Robust.Shared/Physics/Systems/RayCastSystem.cs

@@ -0,0 +1,465 @@
+using System;
+using System.Collections.Generic;
+using System.Numerics;
+using JetBrains.Annotations;
+using Robust.Shared.Collections;
+using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.Map;
+using Robust.Shared.Map.Components;
+using Robust.Shared.Maths;
+using Robust.Shared.Physics.Collision;
+using Robust.Shared.Physics.Collision.Shapes;
+using Robust.Shared.Physics.Dynamics;
+using Robust.Shared.Physics.Shapes;
+using Robust.Shared.Utility;
+
+namespace Robust.Shared.Physics.Systems;
+
+public sealed partial class RayCastSystem : EntitySystem
+{
+    /*
+     * A few things to keep in mind with the below:
+     * - Raycasts are done relative to the corresponding broadphases.
+     * - The raycast results need to be transformed into Map terms.
+     * - If you wish to add more helper methods make a new partial and dump them there and have them call the below methods.
+     */
+
+    [Dependency] private readonly SharedBroadphaseSystem _broadphase = default!;
+    [Dependency] private readonly SharedPhysicsSystem _physics = default!;
+
+    private readonly RayComparer _rayComparer = new();
+
+    #region RayCast
+
+    private sealed class RayComparer : IComparer<RayHit>
+    {
+        public int Compare(RayHit x, RayHit y)
+        {
+            return x.Fraction.CompareTo(y.Fraction);
+        }
+    }
+
+    private void AdjustResults(ref RayResult result, int index, Transform xf)
+    {
+        for (var i = index; i < result.Results.Count; i++)
+        {
+            result.Results[i].Point = Physics.Transform.Mul(xf, result.Results[i].Point);
+        }
+    }
+
+    /*
+     * Raycasts that return all entities sorted.
+     */
+
+    /// <summary>
+    /// Casts a ray against a broadphase.
+    /// </summary>
+    public void CastRay(Entity<BroadphaseComponent?> entity, ref RayResult result, Vector2 origin, Vector2 translation, QueryFilter filter, bool sorted = true)
+    {
+        if (!Resolve(entity.Owner, ref entity.Comp))
+            return;
+
+        DebugTools.Assert(origin.IsValid());
+        DebugTools.Assert(translation.IsValid());
+
+        var input = new RayCastInput()
+        {
+            Origin = origin,
+            Translation = translation,
+            MaxFraction = 1f,
+        };
+
+        var worldContext = new WorldRayCastContext()
+        {
+            fcn = RayCastAllCallback,
+            Filter = filter,
+            Fraction = 1f,
+            Physics = _physics,
+            System = this,
+            Result = result,
+        };
+
+        entity.Comp.DynamicTree.Tree.RayCastNew(input, filter.MaskBits, ref worldContext, RayCastCallback);
+        input.MaxFraction = worldContext.Fraction;
+        entity.Comp.StaticTree.Tree.RayCastNew(input, filter.MaskBits, ref worldContext, RayCastCallback);
+        result = worldContext.Result;
+
+        if (sorted)
+        {
+            result.Results.Sort(_rayComparer);
+        }
+    }
+
+    /// <summary>
+    /// Returns all entities hit in order.
+    /// </summary>
+    [Pure]
+    public RayResult CastRay(MapId mapId, Vector2 origin, Vector2 translation, QueryFilter filter)
+    {
+        DebugTools.Assert(origin.IsValid());
+        DebugTools.Assert(translation.IsValid());
+
+        var input = new RayCastInput
+        {
+            Origin = origin,
+            Translation = translation,
+            MaxFraction = 1.0f
+        };
+
+        var result = new RayResult();
+
+        var start = origin;
+        var end = origin + translation;
+
+        var aabb = new Box2(Vector2.Min(start, end), Vector2.Max(start, end));
+        var state = (input, filter, result, this, _physics);
+
+        _broadphase.GetBroadphases(mapId, aabb, ref state,
+            static (Entity<BroadphaseComponent> entity, ref (RayCastInput input, QueryFilter filter, RayResult result, RayCastSystem system, SharedPhysicsSystem Physics) tuple) =>
+            {
+                var transform = tuple.Physics.GetPhysicsTransform(entity.Owner);
+                var localOrigin = Physics.Transform.InvTransformPoint(transform, tuple.input.Origin);
+                var localTranslation = Physics.Transform.InvTransformPoint(transform, tuple.input.Origin + tuple.input.Translation) - localOrigin;
+                var oldIndex = tuple.result.Results.Count;
+                tuple.system.CastRay((entity.Owner, entity.Comp), ref tuple.result, localOrigin, localTranslation, filter: tuple.filter, sorted: false);
+                tuple.system.AdjustResults(ref tuple.result, oldIndex, transform);
+            });
+
+        result = state.result;
+        result.Results.Sort(_rayComparer);
+        return result;
+    }
+
+    /*
+     * Raycasts that only return the closest entity.
+     */
+
+    /// <summary>
+    /// Casts a ray against a broadphase.
+    /// </summary>
+    public void CastRayClosest(Entity<BroadphaseComponent?> entity, ref RayResult result, Vector2 origin, Vector2 translation, QueryFilter filter)
+    {
+        if (!Resolve(entity.Owner, ref entity.Comp))
+            return;
+
+        DebugTools.Assert(origin.IsValid());
+        DebugTools.Assert(translation.IsValid());
+
+        var input = new RayCastInput()
+        {
+            Origin = origin,
+            Translation = translation,
+            MaxFraction = 1f,
+        };
+
+        var worldContext = new WorldRayCastContext()
+        {
+            fcn = RayCastClosestCallback,
+            Filter = filter,
+            Fraction = 1f,
+            Physics = _physics,
+            System = this,
+            Result = result,
+        };
+
+        entity.Comp.DynamicTree.Tree.RayCastNew(input, filter.MaskBits, ref worldContext, RayCastCallback);
+        input.MaxFraction = worldContext.Fraction;
+        entity.Comp.StaticTree.Tree.RayCastNew(input, filter.MaskBits, ref worldContext, RayCastCallback);
+        result = worldContext.Result;
+        DebugTools.Assert(result.Results.Count <= 1);
+    }
+
+    /// <summary>
+    /// Returns all entities hit in order.
+    /// </summary>
+    public RayResult CastRayClosest(MapId mapId, Vector2 origin, Vector2 translation, QueryFilter filter)
+    {
+        DebugTools.Assert(origin.IsValid());
+        DebugTools.Assert(translation.IsValid());
+
+        var input = new RayCastInput
+        {
+            Origin = origin,
+            Translation = translation,
+            MaxFraction = 1.0f
+        };
+
+        var result = new RayResult();
+
+        var end = origin + translation;
+
+        var aabb = new Box2(Vector2.Min(origin, end), Vector2.Max(origin, end));
+        var state = (input, filter, result, this, _physics);
+
+        _broadphase.GetBroadphases(mapId, aabb, ref state,
+            static (Entity<BroadphaseComponent> entity, ref (RayCastInput input, QueryFilter filter, RayResult result, RayCastSystem system, SharedPhysicsSystem _physics) tuple) =>
+            {
+                var transform = tuple._physics.GetPhysicsTransform(entity.Owner);
+                var localOrigin = Physics.Transform.InvTransformPoint(transform, tuple.input.Origin);
+                var localTranslation = Physics.Transform.InvTransformPoint(transform, tuple.input.Origin + tuple.input.Translation) - localOrigin;
+
+                var oldIndex = tuple.result.Results.Count;
+                tuple.system.CastRayClosest((entity.Owner, entity.Comp), ref tuple.result, localOrigin, localTranslation, filter: tuple.filter);
+                tuple.system.AdjustResults(ref tuple.result, oldIndex, transform);
+            });
+
+        result = state.result;
+        DebugTools.Assert(result.Results.Count <= 1);
+        return result;
+    }
+
+    #endregion
+
+    #region ShapeCast
+
+    /// <summary>
+    /// Convenience method for shape casts; only supports shapes with area.
+    /// </summary>
+    public RayResult CastShape(
+        MapId mapId,
+        IPhysShape shape,
+        Transform originTransform,
+        Vector2 translation,
+        QueryFilter filter,
+        CastResult callback)
+    {
+        DebugTools.Assert(originTransform.Position.IsValid());
+        DebugTools.Assert(originTransform.Quaternion2D.IsValid());
+        DebugTools.Assert(translation.IsValid());
+
+        // Need to get the entire shape AABB to know what broadphases to even query.
+        var startAabb = shape.ComputeAABB(originTransform, 0);
+        var endAabb = shape.ComputeAABB(new Transform(originTransform.Position + translation, originTransform.Quaternion2D.Angle), 0);
+        var aabb = startAabb.Union(endAabb);
+
+        var result = new RayResult();
+        var state = (originTransform, translation, shape: shape, filter, result, this, _physics, callback);
+
+        _broadphase.GetBroadphases(mapId, aabb, ref state,
+            static (
+                Entity<BroadphaseComponent> entity,
+                ref (Transform origin, Vector2 translation, IPhysShape shape, QueryFilter filter, RayResult result, RayCastSystem system, SharedPhysicsSystem _physics, CastResult callback
+                    ) tuple) =>
+            {
+                var transform = tuple._physics.GetPhysicsTransform(entity.Owner);
+                var localOrigin = Physics.Transform.MulT(transform, tuple.origin);
+                var localTranslation = Physics.Transform.InvTransformPoint(transform, tuple.origin.Position + tuple.translation) - localOrigin.Position;
+
+                var oldIndex = tuple.result.Results.Count;
+                tuple.system.CastShape((entity.Owner, entity.Comp), ref tuple.result, tuple.shape, localOrigin, localTranslation, filter: tuple.filter, callback: tuple.callback);
+                tuple.system.AdjustResults(ref tuple.result, oldIndex, transform);
+            });
+
+        result = state.result;
+        return result;
+    }
+
+    /// <summary>
+    /// Cast on the broadphase.
+    /// </summary>
+    public void CastShape(
+        Entity<BroadphaseComponent?> entity,
+        ref RayResult result,
+        IPhysShape shape,
+        Transform originTransform,
+        Vector2 translation,
+        QueryFilter filter,
+        CastResult callback)
+    {
+        if (!Resolve(entity.Owner, ref entity.Comp))
+            return;
+
+        switch (shape)
+        {
+            case PhysShapeCircle circle:
+                CastCircle(entity, ref result, circle, originTransform, translation, filter, callback);
+                break;
+            case Polygon poly:
+                CastPolygon(entity, ref result, new PolygonShape(poly), originTransform, translation, filter, callback);
+                break;
+            case PolygonShape polygon:
+                CastPolygon(entity, ref result, polygon, originTransform, translation, filter, callback);
+                break;
+            default:
+                Log.Error("Tried to shapecast for shape not implemented.");
+                DebugTools.Assert(false);
+                return;
+        }
+    }
+
+    public void CastCircle(
+        Entity<BroadphaseComponent?> entity,
+        ref RayResult result,
+        PhysShapeCircle circle,
+        Transform originTransform,
+        Vector2 translation,
+        QueryFilter filter,
+        CastResult callback)
+    {
+        if (!Resolve(entity.Owner, ref entity.Comp))
+            return;
+
+        var input = new ShapeCastInput()
+        {
+            Points = new Vector2[1],
+            Count = 1,
+            Radius = circle.Radius,
+            Translation = translation,
+            MaxFraction = 1f,
+        };
+
+        input.Points[0] = Physics.Transform.Mul(originTransform, circle.Position);
+
+        var worldContext = new WorldRayCastContext()
+        {
+            System = this,
+            Physics = _physics,
+            Filter = filter,
+            Fraction = 1f,
+            Result = result,
+            fcn = callback,
+        };
+
+        entity.Comp.StaticTree.Tree.ShapeCast(input, filter.MaskBits, ShapeCastCallback, ref worldContext);
+        input.MaxFraction = worldContext.Fraction;
+        entity.Comp.DynamicTree.Tree.ShapeCast(input, filter.MaskBits, ShapeCastCallback, ref worldContext);
+        result = worldContext.Result;
+    }
+
+    public void CastPolygon(
+        Entity<BroadphaseComponent?> entity,
+        ref RayResult result,
+        PolygonShape polygon,
+        Transform originTransform,
+        Vector2 translation,
+        QueryFilter filter,
+        CastResult callback)
+    {
+        if (!Resolve(entity.Owner, ref entity.Comp))
+            return;
+
+        ShapeCastInput input = new()
+        {
+            Points = new Vector2[polygon.VertexCount],
+        };
+
+        for ( int i = 0; i < polygon.VertexCount; ++i )
+        {
+            input.Points[i] = Physics.Transform.Mul(originTransform, polygon.Vertices[i]);
+        }
+
+        input.Count = polygon.VertexCount;
+        input.Radius = polygon.Radius;
+        input.Translation = translation;
+        input.MaxFraction = 1.0f;
+
+        var worldContext = new WorldRayCastContext()
+        {
+            System = this,
+            Physics = _physics,
+            Filter = filter,
+            Fraction = 1f,
+            Result = result,
+            fcn = callback,
+        };
+
+        if ((filter.Flags & QueryFlags.Static) == QueryFlags.Static)
+        {
+            entity.Comp.StaticTree.Tree.ShapeCast(input, filter.MaskBits, ShapeCastCallback, ref worldContext);
+            input.MaxFraction = worldContext.Fraction;
+        }
+
+        if ((filter.Flags & QueryFlags.Dynamic) == QueryFlags.Dynamic)
+        {
+            entity.Comp.DynamicTree.Tree.ShapeCast(input, filter.MaskBits, ShapeCastCallback, ref worldContext);
+        }
+
+        result = worldContext.Result;
+    }
+
+    #endregion
+}
+
+/// Result from b2World_RayCastClosest
+/// @ingroup world
+public record struct RayResult()
+{
+    public ValueList<RayHit> Results = new();
+
+    public bool Hit => Results.Count > 0;
+
+    public static readonly RayResult Empty = new();
+}
+
+public record struct RayHit(EntityUid Entity, Vector2 LocalNormal, float Fraction)
+{
+    public readonly EntityUid Entity = Entity;
+    public readonly Vector2 LocalNormal = LocalNormal;
+    public readonly float Fraction = Fraction;
+
+    // When this point gets added it's in broadphase terms, then the caller handles whether it gets turned into map-terms.
+
+    public Vector2 Point;
+}
+
+/// The query filter is used to filter collisions between queries and shapes. For example,
+///	you may want a ray-cast representing a projectile to hit players and the static environment
+///	but not debris.
+/// @ingroup shape
+public record struct QueryFilter()
+{
+    /// <summary>
+    /// The collision category bits of this query. Normally you would just set one bit.
+    /// </summary>
+    public long LayerBits;
+
+    /// <summary>
+    /// The collision mask bits. This states the shape categories that this
+    /// query would accept for collision.
+    /// </summary>
+    public long MaskBits;
+
+    /// <summary>
+    /// Return whether to ignore an entity.
+    /// </summary>
+    public Func<EntityUid, bool>? IsIgnored;
+
+    public QueryFlags Flags = QueryFlags.Dynamic | QueryFlags.Static;
+}
+
+/// <summary>
+/// Which trees we wish to query.
+/// </summary>
+[Flags]
+public enum QueryFlags : byte
+{
+    None = 0,
+
+    Dynamic = 1 << 0,
+
+    Static = 1 << 1,
+
+    Sensors = 1 << 2,
+
+    // StaticSundries = 1 << 3,
+
+    // Sundries = 1 << 4,
+}
+
+/// Prototype callback for ray casts.
+/// Called for each shape found in the query. You control how the ray cast
+/// proceeds by returning a float:
+/// return -1: ignore this shape and continue
+/// return 0: terminate the ray cast
+/// return fraction: clip the ray to this point
+/// return 1: don't clip the ray and continue
+/// @param shapeId the shape hit by the ray
+/// @param point the point of initial intersection
+/// @param normal the normal vector at the point of intersection
+/// @param fraction the fraction along the ray at the point of intersection
+///	@param context the user context
+/// @return -1 to filter, 0 to terminate, fraction to clip the ray for closest hit, 1 to continue
+/// @see b2World_CastRay
+///	@ingroup world
+public delegate float CastResult(FixtureProxy proxy, Vector2 point, Vector2 normal, float fraction, ref RayResult result);

Robust.Shared/Physics/Systems/SharedBroadphaseSystem.cs

@@ -4,6 +4,7 @@ using System.Collections.Generic;
 using System.Numerics;
 using System.Threading.Tasks;
 using Microsoft.Extensions.ObjectPool;
+using Robust.Shared.Collections;
 using Robust.Shared.Configuration;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
@@ -471,38 +472,54 @@ namespace Robust.Shared.Physics.Systems
             TouchProxies(xform.MapUid.Value, matrix, fixture);
         }
 
-        // TODO: The below is slow and should just query the map's broadphase directly. The problem is that
-        // there's some ordering stuff going on where the broadphase has queued all of its updates but hasn't applied
-        // them yet so this query will fail on initialization which chains into a whole lot of issues.
-        internal IEnumerable<(EntityUid uid, BroadphaseComponent comp)> GetBroadphases(MapId mapId, Box2 aabb)
+        internal void GetBroadphases(MapId mapId, Box2 aabb,BroadphaseCallback callback)
         {
-            // TODO Okay so problem: If we just do Encloses that's a lot faster BUT it also means we don't return the
-            // map's broadphase which avoids us iterating over it for 99% of bodies.
+            var internalState = (callback, _broadphaseQuery);
 
-            if (mapId == MapId.Nullspace) yield break;
-
-            var enumerator = AllEntityQuery<BroadphaseComponent, TransformComponent>();
-
-            while (enumerator.MoveNext(out var bUid, out var broadphase, out var xform))
-            {
-                if (xform.MapID != mapId) continue;
-
-                if (!EntityManager.TryGetComponent(bUid, out MapGridComponent? mapGrid))
+            _mapManager.FindGridsIntersecting(mapId,
+                aabb,
+                ref internalState,
+                static (
+                    EntityUid uid,
+                    MapGridComponent grid,
+                    ref (BroadphaseCallback callback, EntityQuery<BroadphaseComponent> _broadphaseQuery) tuple) =>
                 {
-                    yield return (bUid, broadphase);
-                    continue;
-                }
+                    if (!tuple._broadphaseQuery.TryComp(uid, out var broadphase))
+                        return true;
 
-                // Won't worry about accurate bounds checks as it's probably slower in most use cases.
-                var chunkEnumerator = _map.GetMapChunks(bUid, mapGrid, aabb);
-
-                if (chunkEnumerator.MoveNext(out _))
-                {
-                    yield return (bUid, broadphase);
-                }
-            }
+                    tuple.callback((uid, broadphase));
+                    return true;
+                    // Approx because we don't really need accurate checks for these most of the time.
+                }, approx: true, includeMap: true);
         }
 
+        internal void GetBroadphases<TState>(MapId mapId, Box2 aabb, ref TState state, BroadphaseCallback<TState> callback)
+        {
+            var internalState = (state, callback, _broadphaseQuery);
+
+            _mapManager.FindGridsIntersecting(mapId,
+                aabb,
+                ref internalState,
+                static (
+                    EntityUid uid,
+                    MapGridComponent grid,
+                    ref (TState state, BroadphaseCallback<TState> callback, EntityQuery<BroadphaseComponent> _broadphaseQuery) tuple) =>
+                {
+                    if (!tuple._broadphaseQuery.TryComp(uid, out var broadphase))
+                        return true;
+
+                    tuple.callback((uid, broadphase), ref tuple.state);
+                    return true;
+                    // Approx because we don't really need accurate checks for these most of the time.
+                }, approx: true, includeMap: true);
+
+            state = internalState.state;
+        }
+
+        internal delegate void BroadphaseCallback(Entity<BroadphaseComponent> entity);
+
+        internal delegate void BroadphaseCallback<TState>(Entity<BroadphaseComponent> entity, ref TState state);
+
         private record struct BroadphaseContactJob() : IParallelRobustJob
         {
             public SharedBroadphaseSystem System = default!;

Robust.Shared/Physics/Systems/SharedPhysicsSystem.Components.cs

@@ -23,7 +23,9 @@
  */
 
 using System;
+using System.Collections.Generic;
 using System.Numerics;
+using Robust.Shared.Collections;
 using Robust.Shared.GameObjects;
 using Robust.Shared.GameStates;
 using Robust.Shared.Map;
@@ -69,39 +71,97 @@ public partial class SharedPhysicsSystem
 
     private void OnPhysicsGetState(EntityUid uid, PhysicsComponent component, ref ComponentGetState args)
     {
-        args.State = new PhysicsComponentState(
-            component.CanCollide,
-            component.SleepingAllowed,
-            component.FixedRotation,
-            component.BodyStatus,
-            component.LinearVelocity,
-            component.AngularVelocity,
-            component.BodyType,
-            component._friction,
-            component.LinearDamping,
-            component.AngularDamping);
+        if (args.FromTick > component.CreationTick && component.LastFieldUpdate >= args.FromTick)
+        {
+            var slowPath = false;
+
+            for (var i = 0; i < _angularVelocityIndex; i++)
+            {
+                var field = component.LastModifiedFields[i];
+
+                if (field < args.FromTick)
+                    continue;
+
+                slowPath = true;
+                break;
+            }
+
+            // We can do a smaller delta with no list index overhead.
+            if (!slowPath)
+            {
+                var angularDirty = component.LastModifiedFields[_angularVelocityIndex] >= args.FromTick;
+
+                if (angularDirty)
+                {
+                    args.State = new PhysicsVelocityDeltaState()
+                    {
+                        AngularVelocity = component.AngularVelocity,
+                        LinearVelocity = component.LinearVelocity,
+                    };
+                }
+                else
+                {
+                    args.State = new PhysicsLinearVelocityDeltaState()
+                    {
+                        LinearVelocity = component.LinearVelocity,
+                    };
+                }
+
+                return;
+            }
+        }
+
+        args.State = new PhysicsComponentState
+        {
+            CanCollide = component.CanCollide,
+            SleepingAllowed = component.SleepingAllowed,
+            FixedRotation = component.FixedRotation,
+            Status = component.BodyStatus,
+            LinearVelocity = component.LinearVelocity,
+            AngularVelocity = component.AngularVelocity,
+            BodyType = component.BodyType,
+            Friction = component._friction,
+            LinearDamping = component.LinearDamping,
+            AngularDamping = component.AngularDamping,
+            Force = component.Force,
+            Torque = component.Torque,
+        };
     }
 
     private void OnPhysicsHandleState(EntityUid uid, PhysicsComponent component, ref ComponentHandleState args)
     {
-        if (args.Current is not PhysicsComponentState newState)
+        if (args.Current == null)
             return;
 
-        SetSleepingAllowed(uid, component, newState.SleepingAllowed);
-        SetFixedRotation(uid, newState.FixedRotation, body: component);
-        SetCanCollide(uid, newState.CanCollide, body: component);
-        component.BodyStatus = newState.Status;
-
         // So transform doesn't apply MapId in the HandleComponentState because ??? so MapId can still be 0.
         // Fucking kill me, please. You have no idea deep the rabbit hole of shitcode goes to make this work.
-        TryComp<FixturesComponent>(uid, out var manager);
+        _fixturesQuery.TryComp(uid, out var manager);
 
-        SetLinearVelocity(uid, newState.LinearVelocity, body: component, manager: manager);
-        SetAngularVelocity(uid, newState.AngularVelocity, body: component, manager: manager);
-        SetBodyType(uid, newState.BodyType, manager, component);
-        SetFriction(uid, component, newState.Friction);
-        SetLinearDamping(uid, component, newState.LinearDamping);
-        SetAngularDamping(uid, component, newState.AngularDamping);
+        if (args.Current is PhysicsLinearVelocityDeltaState linearState)
+        {
+            SetLinearVelocity(uid, linearState.LinearVelocity, body: component, manager: manager);
+        }
+        else if (args.Current is PhysicsVelocityDeltaState velocityState)
+        {
+            SetLinearVelocity(uid, velocityState.LinearVelocity, body: component, manager: manager);
+            SetAngularVelocity(uid, velocityState.AngularVelocity, body: component, manager: manager);
+        }
+        else if (args.Current is PhysicsComponentState newState)
+        {
+            SetSleepingAllowed(uid, component, newState.SleepingAllowed);
+            SetFixedRotation(uid, newState.FixedRotation, body: component);
+            SetCanCollide(uid, newState.CanCollide, body: component);
+            component.BodyStatus = newState.Status;
+
+            SetLinearVelocity(uid, newState.LinearVelocity, body: component, manager: manager);
+            SetAngularVelocity(uid, newState.AngularVelocity, body: component, manager: manager);
+            SetBodyType(uid, newState.BodyType, manager, component);
+            SetFriction(uid, component, newState.Friction);
+            SetLinearDamping(uid, component, newState.LinearDamping);
+            SetAngularDamping(uid, component, newState.AngularDamping);
+            component.Force = newState.Force;
+            component.Torque = newState.Torque;
+        }
     }
 
     #endregion
@@ -132,7 +192,6 @@ public partial class SharedPhysicsSystem
 
         body.Force += force;
         body.Torque += Vector2Helpers.Cross(point - body._localCenter, force);
-        Dirty(uid, body);
     }
 
     public void ApplyForce(EntityUid uid, Vector2 force, FixturesComponent? manager = null, PhysicsComponent? body = null)
@@ -143,7 +202,6 @@ public partial class SharedPhysicsSystem
         }
 
         body.Force += force;
-        Dirty(uid, body);
     }
 
     public void ApplyTorque(EntityUid uid, float torque, FixturesComponent? manager = null, PhysicsComponent? body = null)
@@ -154,7 +212,7 @@ public partial class SharedPhysicsSystem
         }
 
         body.Torque += torque;
-        Dirty(uid, body);
+        DirtyField(uid, body, nameof(PhysicsComponent.Torque));
     }
 
     public void ApplyLinearImpulse(EntityUid uid, Vector2 impulse, FixturesComponent? manager = null, PhysicsComponent? body = null)
@@ -212,34 +270,29 @@ public partial class SharedPhysicsSystem
     /// </summary>
     public void ResetDynamics(EntityUid uid, PhysicsComponent body, bool dirty = true)
     {
-        var updated = false;
-
         if (body.Torque != 0f)
         {
             body.Torque = 0f;
-            updated = true;
+            DirtyField(uid, body, nameof(PhysicsComponent.Torque));
         }
 
         if (body.AngularVelocity != 0f)
         {
             body.AngularVelocity = 0f;
-            updated = true;
+            DirtyField(uid, body, nameof(PhysicsComponent.AngularVelocity));
         }
 
         if (body.Force != Vector2.Zero)
         {
             body.Force = Vector2.Zero;
-            updated = true;
+            DirtyField(uid, body, nameof(PhysicsComponent.Force));
         }
 
         if (body.LinearVelocity != Vector2.Zero)
         {
             body.LinearVelocity = Vector2.Zero;
-            updated = true;
+            DirtyField(uid, body, nameof(PhysicsComponent.LinearVelocity));
         }
-
-        if (updated && dirty)
-            Dirty(uid, body);
     }
 
     public void ResetMassData(EntityUid uid, FixturesComponent? manager = null, PhysicsComponent? body = null)
@@ -275,7 +328,6 @@ public partial class SharedPhysicsSystem
         if (((int) body.BodyType & (int) (BodyType.Kinematic | BodyType.Static)) != 0)
         {
             body._localCenter = Vector2.Zero;
-            Dirty(uid, body);
             return;
         }
 
@@ -309,8 +361,13 @@ public partial class SharedPhysicsSystem
         body._localCenter = localCenter;
 
         // Update center of mass velocity.
-        body.LinearVelocity += Vector2Helpers.Cross(body.AngularVelocity, localCenter - oldCenter);
-        Dirty(uid, body);
+        var comVelocityDiff = Vector2Helpers.Cross(body.AngularVelocity, localCenter - oldCenter);
+
+        if (comVelocityDiff != Vector2.Zero)
+       	{
+       		body.LinearVelocity += comVelocityDiff;
+        	DirtyField(uid, body, nameof(PhysicsComponent.LinearVelocity));
+       	}
 
         if (body._mass == oldMass && body._inertia == oldInertia && oldCenter == localCenter)
             return;
@@ -340,9 +397,7 @@ public partial class SharedPhysicsSystem
             return false;
 
         body.AngularVelocity = value;
-
-        if (dirty)
-            Dirty(uid, body);
+        DirtyField(uid, body, nameof(PhysicsComponent.AngularVelocity));
 
         return true;
     }
@@ -368,10 +423,7 @@ public partial class SharedPhysicsSystem
             return false;
 
         body.LinearVelocity = velocity;
-
-        if (dirty)
-            Dirty(uid, body);
-
+        DirtyField(uid, body, nameof(PhysicsComponent.LinearVelocity));
         return true;
     }
 
@@ -381,9 +433,7 @@ public partial class SharedPhysicsSystem
             return;
 
         body.AngularDamping = value;
-
-        if (dirty)
-            Dirty(uid, body);
+        DirtyField(uid, body, nameof(PhysicsComponent.AngularDamping));
     }
 
     public void SetLinearDamping(EntityUid uid, PhysicsComponent body, float value, bool dirty = true)
@@ -392,9 +442,7 @@ public partial class SharedPhysicsSystem
             return;
 
         body.LinearDamping = value;
-
-        if (dirty)
-            Dirty(uid, body);
+        DirtyField(uid, body, nameof(PhysicsComponent.LinearDamping));
     }
 
     [Obsolete("Use SetAwake with EntityUid<PhysicsComponent>")]
@@ -446,7 +494,6 @@ public partial class SharedPhysicsSystem
         }
 
         UpdateMapAwakeState(uid, body);
-        Dirty(ent);
     }
 
     public void TrySetBodyType(EntityUid uid, BodyType value, FixturesComponent? manager = null, PhysicsComponent? body = null, TransformComponent? xform = null)
@@ -474,8 +521,18 @@ public partial class SharedPhysicsSystem
         if (body.BodyType == BodyType.Static)
         {
             SetAwake((uid, body), false);
-            body.LinearVelocity = Vector2.Zero;
-            body.AngularVelocity = 0.0f;
+
+            if (body.LinearVelocity != Vector2.Zero)
+            {
+                body.LinearVelocity = Vector2.Zero;
+                DirtyField(uid, body, nameof(PhysicsComponent.LinearVelocity));
+            }
+
+            if (body.AngularVelocity != 0f)
+            {
+                body.AngularVelocity = 0f;
+                DirtyField(uid, body, nameof(PhysicsComponent.AngularVelocity));
+            }
         }
         // Even if it's dynamic if it can't collide then don't force it awake.
         else if (body.CanCollide)
@@ -483,8 +540,11 @@ public partial class SharedPhysicsSystem
             SetAwake((uid, body), true);
         }
 
-        body.Force = Vector2.Zero;
-        body.Torque = 0.0f;
+        if (body.Torque != 0f)
+        {
+            body.Torque = 0f;
+            DirtyField(uid, body, nameof(PhysicsComponent.Torque));
+        }
 
         _broadphase.RegenerateContacts(uid, body, manager, xform);
 
@@ -501,9 +561,7 @@ public partial class SharedPhysicsSystem
             return;
 
         body.BodyStatus = status;
-
-        if (dirty)
-            Dirty(uid, body);
+        DirtyField(uid, body, nameof(PhysicsComponent.BodyStatus));
     }
 
     /// <summary>
@@ -554,10 +612,7 @@ public partial class SharedPhysicsSystem
             var ev = new CollisionChangeEvent(uid, body, value);
             RaiseLocalEvent(ref ev);
         }
-
-        if (dirty)
-            Dirty(uid, body);
-
+        DirtyField(uid, body, nameof(PhysicsComponent.CanCollide));
         return value;
     }
 
@@ -567,11 +622,15 @@ public partial class SharedPhysicsSystem
             return;
 
         body.FixedRotation = value;
-        body.AngularVelocity = 0.0f;
-        ResetMassData(uid, manager: manager, body: body);
+        DirtyField(uid, body, nameof(PhysicsComponent.FixedRotation));
 
-        if (dirty)
-            Dirty(uid, body);
+        if (body.AngularVelocity != 0f)
+        {
+            body.AngularVelocity = 0.0f;
+            DirtyField(uid, body, nameof(PhysicsComponent.AngularVelocity));
+        }
+
+        ResetMassData(uid, manager: manager, body: body);
     }
 
     public void SetFriction(EntityUid uid, PhysicsComponent body, float value, bool dirty = true)
@@ -580,9 +639,7 @@ public partial class SharedPhysicsSystem
             return;
 
         body._friction = value;
-
-        if (dirty)
-            Dirty(uid, body);
+        DirtyField(uid, body, nameof(PhysicsComponent.Friction));
     }
 
     public void SetInertia(EntityUid uid, PhysicsComponent body, float value, bool dirty = true)
@@ -598,9 +655,7 @@ public partial class SharedPhysicsSystem
             body._inertia = value - body.Mass * Vector2.Dot(body._localCenter, body._localCenter);
             DebugTools.Assert(body._inertia > 0.0f);
             body.InvI = 1.0f / body._inertia;
-
-            if (dirty)
-                Dirty(uid, body);
+            // Not networked
         }
     }
 
@@ -611,6 +666,7 @@ public partial class SharedPhysicsSystem
         if (value.EqualsApprox(body._localCenter)) return;
 
         body._localCenter = value;
+        // Not networked
     }
 
     public void SetSleepingAllowed(EntityUid uid, PhysicsComponent body, bool value, bool dirty = true)
@@ -622,9 +678,7 @@ public partial class SharedPhysicsSystem
             SetAwake((uid, body), true);
 
         body.SleepingAllowed = value;
-
-        if (dirty)
-            Dirty(uid, body);
+        DirtyField(uid, body, nameof(PhysicsComponent.SleepingAllowed));
     }
 
     public void SetSleepTime(PhysicsComponent body, float value)

Robust.Shared/Physics/Systems/SharedPhysicsSystem.Queries.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Numerics;
+using Robust.Shared.Collections;
 using Robust.Shared.Debugging;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
@@ -34,37 +35,48 @@ namespace Robust.Shared.Physics.Systems
         public bool TryCollideRect(Box2 collider, MapId mapId, bool approximate = true)
         {
             var state = (collider, mapId, found: false);
+            var broadphases = new ValueList<Entity<BroadphaseComponent>>();
 
-            foreach (var (uid, broadphase) in _broadphase.GetBroadphases(mapId, collider))
-            {
-                var gridCollider = _transform.GetInvWorldMatrix(uid).TransformBox(collider);
-
-                broadphase.StaticTree.QueryAabb(ref state, (ref (Box2 collider, MapId map, bool found) state, in FixtureProxy proxy) =>
+            _broadphase.GetBroadphases(mapId,
+                collider,
+                broadphase =>
                 {
-                    if (proxy.Fixture.CollisionLayer == 0x0)
-                        return true;
+                    var gridCollider = _transform.GetInvWorldMatrix(broadphase).TransformBox(collider);
 
-                    if (proxy.AABB.Intersects(gridCollider))
-                    {
-                        state.found = true;
-                        return false;
-                    }
-                    return true;
-                }, gridCollider, approximate);
+                    broadphase.Comp.StaticTree.QueryAabb(ref state,
+                        (ref (Box2 collider, MapId map, bool found) state, in FixtureProxy proxy) =>
+                        {
+                            if (proxy.Fixture.CollisionLayer == 0x0)
+                                return true;
 
-                broadphase.DynamicTree.QueryAabb(ref state, (ref (Box2 collider, MapId map, bool found) state, in FixtureProxy proxy) =>
-                {
-                    if (proxy.Fixture.CollisionLayer == 0x0)
-                        return true;
+                            if (proxy.AABB.Intersects(gridCollider))
+                            {
+                                state.found = true;
+                                return false;
+                            }
 
-                    if (proxy.AABB.Intersects(gridCollider))
-                    {
-                        state.found = true;
-                        return false;
-                    }
-                    return true;
-                }, gridCollider, approximate);
-            }
+                            return true;
+                        },
+                        gridCollider,
+                        approximate);
+
+                    broadphase.Comp.DynamicTree.QueryAabb(ref state,
+                        (ref (Box2 collider, MapId map, bool found) state, in FixtureProxy proxy) =>
+                        {
+                            if (proxy.Fixture.CollisionLayer == 0x0)
+                                return true;
+
+                            if (proxy.AABB.Intersects(gridCollider))
+                            {
+                                state.found = true;
+                                return false;
+                            }
+
+                            return true;
+                        },
+                        gridCollider,
+                        approximate);
+                });
 
             return state.found;
         }
@@ -130,22 +142,27 @@ namespace Robust.Shared.Physics.Systems
         {
             if (mapId == MapId.Nullspace) return Array.Empty<PhysicsComponent>();
 
+            var aabb = worldAABB;
             var bodies = new HashSet<PhysicsComponent>();
+            var state = (_transform, bodies, aabb);
 
-            foreach (var (uid, broadphase) in _broadphase.GetBroadphases(mapId, worldAABB))
-            {
-                var gridAABB = _transform.GetInvWorldMatrix(uid).TransformBox(worldAABB);
-
-                foreach (var proxy in broadphase.StaticTree.QueryAabb(gridAABB, false))
+            _broadphase.GetBroadphases(mapId, worldAABB, ref state, static
+                (
+                    Entity<BroadphaseComponent> entity,
+                    ref (SharedTransformSystem _transform, HashSet<PhysicsComponent> bodies, Box2 aabb) tuple) =>
                 {
-                    bodies.Add(proxy.Body);
-                }
+                    var gridAABB = tuple._transform.GetInvWorldMatrix(entity.Owner).TransformBox(tuple.aabb);
 
-                foreach (var proxy in broadphase.DynamicTree.QueryAabb(gridAABB, false))
-                {
-                    bodies.Add(proxy.Body);
-                }
-            }
+                    foreach (var proxy in entity.Comp.StaticTree.QueryAabb(gridAABB, false))
+                    {
+                        tuple.bodies.Add(proxy.Body);
+                    }
+
+                    foreach (var proxy in entity.Comp.DynamicTree.QueryAabb(gridAABB, false))
+                    {
+                        tuple.bodies.Add(proxy.Body);
+                    }
+                });
 
             return bodies;
         }
@@ -160,20 +177,27 @@ namespace Robust.Shared.Physics.Systems
 
             var bodies = new HashSet<Entity<PhysicsComponent>>();
 
-            foreach (var (uid, broadphase) in _broadphase.GetBroadphases(mapId, worldBounds.CalcBoundingBox()))
-            {
-                var gridAABB = _transform.GetInvWorldMatrix(uid).TransformBox(worldBounds);
+            var state = (_transform, bodies, worldBounds);
 
-                foreach (var proxy in broadphase.StaticTree.QueryAabb(gridAABB, false))
+            _broadphase.GetBroadphases(mapId, worldBounds.CalcBoundingBox(), ref state,
+                static (
+                    Entity<BroadphaseComponent> entity,
+                    ref (SharedTransformSystem _transform, HashSet<Entity<PhysicsComponent>> bodies, Box2Rotated
+                        worldBounds
+                        ) tuple) =>
                 {
-                    bodies.Add(new Entity<PhysicsComponent>(proxy.Entity, proxy.Body));
-                }
+                    var gridAABB = tuple._transform.GetInvWorldMatrix(entity.Owner).TransformBox(tuple.worldBounds);
 
-                foreach (var proxy in broadphase.DynamicTree.QueryAabb(gridAABB, false))
-                {
-                    bodies.Add(new Entity<PhysicsComponent>(proxy.Entity, proxy.Body));
-                }
-            }
+                    foreach (var proxy in entity.Comp.StaticTree.QueryAabb(gridAABB, false))
+                    {
+                        tuple.bodies.Add((proxy.Entity, proxy.Body));
+                    }
+
+                    foreach (var proxy in entity.Comp.DynamicTree.QueryAabb(gridAABB, false))
+                    {
+                        tuple.bodies.Add((proxy.Entity, proxy.Body));
+                    }
+                });
 
             return bodies;
         }
@@ -263,72 +287,91 @@ namespace Robust.Shared.Physics.Systems
             var rayBox = new Box2(Vector2.Min(ray.Position, endPoint),
                 Vector2.Max(ray.Position, endPoint));
 
-            foreach (var (uid, broadphase) in _broadphase.GetBroadphases(mapId, rayBox))
-            {
-                var (_, rot, matrix, invMatrix) = _transform.GetWorldPositionRotationMatrixWithInv(uid);
-
-                var position = Vector2.Transform(ray.Position, invMatrix);
-                var gridRot = new Angle(-rot.Theta);
-                var direction = gridRot.RotateVec(ray.Direction);
-
-                var gridRay = new CollisionRay(position, direction, ray.CollisionMask);
-
-                broadphase.StaticTree.QueryRay((in FixtureProxy proxy, in Vector2 point, float distFromOrigin) =>
+            _broadphase.GetBroadphases(mapId,
+                rayBox,
+                broadphase =>
                 {
-                    if (returnOnFirstHit && results.Count > 0)
-                        return true;
+                    var (_, rot, matrix, invMatrix) =
+                        _transform.GetWorldPositionRotationMatrixWithInv(broadphase.Owner);
 
-                    if (distFromOrigin > maxLength)
-                        return true;
+                    var position = Vector2.Transform(ray.Position, invMatrix);
+                    var gridRot = new Angle(-rot.Theta);
+                    var direction = gridRot.RotateVec(ray.Direction);
 
-                    if ((proxy.Fixture.CollisionLayer & ray.CollisionMask) == 0x0)
-                        return true;
+                    var gridRay = new CollisionRay(position, direction, ray.CollisionMask);
 
-                    if (!proxy.Fixture.Hard)
-                        return true;
+                    broadphase.Comp.StaticTree.QueryRay(
+                        (in FixtureProxy proxy, in Vector2 point, float distFromOrigin) =>
+                        {
+                            if (returnOnFirstHit && results.Count > 0)
+                                return true;
 
-                    if (predicate.Invoke(proxy.Entity, state) == true)
-                        return true;
+                            if (distFromOrigin > maxLength)
+                                return true;
 
-                    // TODO: Shape raycast here
+                            if ((proxy.Fixture.CollisionLayer & ray.CollisionMask) == 0x0)
+                                return true;
 
-                    // Need to convert it back to world-space.
-                    var result = new RayCastResults(distFromOrigin, Vector2.Transform(point, matrix), proxy.Entity);
-                    results.Add(result);
+                            if (!proxy.Fixture.Hard)
+                                return true;
+
+                            if (predicate.Invoke(proxy.Entity, state) == true)
+                                return true;
+
+                            // TODO: Shape raycast here
+
+                            // Need to convert it back to world-space.
+                            var result = new RayCastResults(distFromOrigin,
+                                Vector2.Transform(point, matrix),
+                                proxy.Entity);
+                            results.Add(result);
 #if DEBUG
-                    _sharedDebugRaySystem.ReceiveLocalRayFromAnyThread(new(ray, maxLength, result, _netMan.IsServer, mapId));
+                            _sharedDebugRaySystem.ReceiveLocalRayFromAnyThread(new(ray,
+                                maxLength,
+                                result,
+                                _netMan.IsServer,
+                                mapId));
 #endif
-                    return true;
-                }, gridRay);
+                            return true;
+                        },
+                        gridRay);
 
-                broadphase.DynamicTree.QueryRay((in FixtureProxy proxy, in Vector2 point, float distFromOrigin) =>
-                {
-                    if (returnOnFirstHit && results.Count > 0)
-                        return true;
+                    broadphase.Comp.DynamicTree.QueryRay(
+                        (in FixtureProxy proxy, in Vector2 point, float distFromOrigin) =>
+                        {
+                            if (returnOnFirstHit && results.Count > 0)
+                                return true;
 
-                    if (distFromOrigin > maxLength)
-                        return true;
+                            if (distFromOrigin > maxLength)
+                                return true;
 
-                    if ((proxy.Fixture.CollisionLayer & ray.CollisionMask) == 0x0)
-                        return true;
+                            if ((proxy.Fixture.CollisionLayer & ray.CollisionMask) == 0x0)
+                                return true;
 
-                    if (!proxy.Fixture.Hard)
-                        return true;
+                            if (!proxy.Fixture.Hard)
+                                return true;
 
-                    if (predicate.Invoke(proxy.Entity, state) == true)
-                        return true;
+                            if (predicate.Invoke(proxy.Entity, state) == true)
+                                return true;
 
-                    // TODO: Shape raycast here
+                            // TODO: Shape raycast here
 
-                    // Need to convert it back to world-space.
-                    var result = new RayCastResults(distFromOrigin, Vector2.Transform(point, matrix), proxy.Entity);
-                    results.Add(result);
+                            // Need to convert it back to world-space.
+                            var result = new RayCastResults(distFromOrigin,
+                                Vector2.Transform(point, matrix),
+                                proxy.Entity);
+                            results.Add(result);
 #if DEBUG
-                    _sharedDebugRaySystem.ReceiveLocalRayFromAnyThread(new(ray, maxLength, result, _netMan.IsServer, mapId));
+                            _sharedDebugRaySystem.ReceiveLocalRayFromAnyThread(new(ray,
+                                maxLength,
+                                result,
+                                _netMan.IsServer,
+                                mapId));
 #endif
-                    return true;
-                }, gridRay);
-            }
+                            return true;
+                        },
+                        gridRay);
+                });
 
 #if DEBUG
             if (results.Count == 0)
@@ -374,54 +417,68 @@ namespace Robust.Shared.Physics.Systems
             var rayBox = new Box2(Vector2.Min(ray.Position, endPoint),
                 Vector2.Max(ray.Position, endPoint));
 
-            foreach (var (uid, broadphase) in _broadphase.GetBroadphases(mapId, rayBox))
-            {
-                var (_, rot, invMatrix) = _transform.GetWorldPositionRotationInvMatrix(uid);
-
-                var position = Vector2.Transform(ray.Position, invMatrix);
-                var gridRot = new Angle(-rot.Theta);
-                var direction = gridRot.RotateVec(ray.Direction);
-
-                var gridRay = new CollisionRay(position, direction, ray.CollisionMask);
-
-                broadphase.StaticTree.QueryRay((in FixtureProxy proxy, in Vector2 point, float distFromOrigin) =>
+            _broadphase.GetBroadphases(mapId,
+                rayBox,
+                broadphase =>
                 {
-                    if (distFromOrigin > maxLength || proxy.Entity == ignoredEnt)
-                        return true;
+                    var (_, rot, invMatrix) = _transform.GetWorldPositionRotationInvMatrix(broadphase);
 
-                    if (!proxy.Fixture.Hard)
-                        return true;
+                    var position = Vector2.Transform(ray.Position, invMatrix);
+                    var gridRot = new Angle(-rot.Theta);
+                    var direction = gridRot.RotateVec(ray.Direction);
 
-                    if ((proxy.Fixture.CollisionLayer & ray.CollisionMask) == 0x0)
-                        return true;
+                    var gridRay = new CollisionRay(position, direction, ray.CollisionMask);
 
-                    if (new Ray(point + gridRay.Direction * proxy.AABB.Size.Length() * 2, -gridRay.Direction).Intersects(
-                            proxy.AABB, out _, out var exitPoint))
-                    {
-                        penetration += (point - exitPoint).Length();
-                    }
-                    return true;
-                }, gridRay);
+                    broadphase.Comp.StaticTree.QueryRay(
+                        (in FixtureProxy proxy, in Vector2 point, float distFromOrigin) =>
+                        {
+                            if (distFromOrigin > maxLength || proxy.Entity == ignoredEnt)
+                                return true;
 
-                broadphase.DynamicTree.QueryRay((in FixtureProxy proxy, in Vector2 point, float distFromOrigin) =>
-                {
-                    if (distFromOrigin > maxLength || proxy.Entity == ignoredEnt)
-                        return true;
+                            if (!proxy.Fixture.Hard)
+                                return true;
 
-                    if (!proxy.Fixture.Hard)
-                        return true;
+                            if ((proxy.Fixture.CollisionLayer & ray.CollisionMask) == 0x0)
+                                return true;
 
-                    if ((proxy.Fixture.CollisionLayer & ray.CollisionMask) == 0x0)
-                        return true;
+                            if (new Ray(point + gridRay.Direction * proxy.AABB.Size.Length() * 2, -gridRay.Direction)
+                                .Intersects(
+                                    proxy.AABB,
+                                    out _,
+                                    out var exitPoint))
+                            {
+                                penetration += (point - exitPoint).Length();
+                            }
 
-                    if (new Ray(point + gridRay.Direction * proxy.AABB.Size.Length() * 2, -gridRay.Direction).Intersects(
-                            proxy.AABB, out _, out var exitPoint))
-                    {
-                        penetration += (point - exitPoint).Length();
-                    }
-                    return true;
-                }, gridRay);
-            }
+                            return true;
+                        },
+                        gridRay);
+
+                    broadphase.Comp.DynamicTree.QueryRay(
+                        (in FixtureProxy proxy, in Vector2 point, float distFromOrigin) =>
+                        {
+                            if (distFromOrigin > maxLength || proxy.Entity == ignoredEnt)
+                                return true;
+
+                            if (!proxy.Fixture.Hard)
+                                return true;
+
+                            if ((proxy.Fixture.CollisionLayer & ray.CollisionMask) == 0x0)
+                                return true;
+
+                            if (new Ray(point + gridRay.Direction * proxy.AABB.Size.Length() * 2, -gridRay.Direction)
+                                .Intersects(
+                                    proxy.AABB,
+                                    out _,
+                                    out var exitPoint))
+                            {
+                                penetration += (point - exitPoint).Length();
+                            }
+
+                            return true;
+                        },
+                        gridRay);
+                });
 
             // This hid rays that didn't penetrate something. Don't hide those because that causes rays to disappear that shouldn't.
 #if DEBUG

Robust.Shared/Physics/Systems/SharedPhysicsSystem.cs

@@ -74,10 +74,32 @@ namespace Robust.Shared.Physics.Systems
         protected EntityQuery<PhysicsMapComponent> PhysMapQuery;
         protected EntityQuery<MapComponent> MapQuery;
 
+        private ComponentRegistration _physicsReg = default!;
+        private byte _angularVelocityIndex;
+
         public override void Initialize()
         {
             base.Initialize();
 
+            _physicsReg = EntityManager.ComponentFactory.GetRegistration(CompIdx.Index<PhysicsComponent>());
+
+            // If you update this then update the delta state + GetState + HandleState!
+            EntityManager.ComponentFactory.RegisterNetworkedFields(_physicsReg,
+                nameof(PhysicsComponent.CanCollide),
+                nameof(PhysicsComponent.BodyStatus),
+                nameof(PhysicsComponent.BodyType),
+                nameof(PhysicsComponent.SleepingAllowed),
+                nameof(PhysicsComponent.FixedRotation),
+                nameof(PhysicsComponent.Friction),
+                nameof(PhysicsComponent.Force),
+                nameof(PhysicsComponent.Torque),
+                nameof(PhysicsComponent.LinearDamping),
+                nameof(PhysicsComponent.AngularDamping),
+                nameof(PhysicsComponent.AngularVelocity),
+                nameof(PhysicsComponent.LinearVelocity));
+
+            _angularVelocityIndex = 10;
+
             _fixturesQuery = GetEntityQuery<FixturesComponent>();
             PhysicsQuery = GetEntityQuery<PhysicsComponent>();
             _xformQuery = GetEntityQuery<TransformComponent>();

Robust.Shared/Physics/Transform.cs

@@ -38,6 +38,12 @@ namespace Robust.Shared.Physics
         public Vector2 Position;
         public Quaternion2D Quaternion2D;
 
+        public Transform(Vector2 position, Quaternion2D quat)
+        {
+            Position = position;
+            Quaternion2D = quat;
+        }
+
         public Transform(Vector2 position, float angle)
         {
             Position = position;
@@ -56,6 +62,16 @@ namespace Robust.Shared.Physics
             Quaternion2D = new Quaternion2D(angle);
         }
 
+        /// Inverse transform a point (e.g. world space to local space)
+        [Pure]
+        public static Vector2 InvTransformPoint(Transform t, Vector2 p)
+        {
+            float vx = p.X - t.Position.X;
+            float vy = p.Y - t.Position.Y;
+            return new Vector2(t.Quaternion2D.C * vx + t.Quaternion2D.S * vy, -t.Quaternion2D.S * vx + t.Quaternion2D.C * vy);
+        }
+
+        [Pure]
         public static Vector2 Mul(in Transform transform, in Vector2 vector)
         {
             float x = (transform.Quaternion2D.C * vector.X - transform.Quaternion2D.S * vector.Y) + transform.Position.X;
@@ -64,12 +80,14 @@ namespace Robust.Shared.Physics
             return new Vector2(x, y);
         }
 
+        [Pure]
         public static Vector2 MulT(in Vector2[] A, in Vector2 v)
         {
             DebugTools.Assert(A.Length == 2);
             return new Vector2(v.X * A[0].X + v.Y * A[0].Y, v.X * A[1].X + v.Y * A[1].Y);
         }
 
+        [Pure]
         public static Vector2 MulT(in Transform T, in Vector2 v)
         {
             float px = v.X - T.Position.X;
@@ -81,6 +99,7 @@ namespace Robust.Shared.Physics
         }
 
         /// Transpose multiply two rotations: qT * r
+        [Pure]
         public static Quaternion2D MulT(in Quaternion2D q, in Quaternion2D r)
         {
             // [ qc qs] * [rc -rs] = [qc*rc+qs*rs -qc*rs+qs*rc]
@@ -93,8 +112,15 @@ namespace Robust.Shared.Physics
             return qr;
         }
 
+        [Pure]
+        public static Transform InvMulTransforms(in Transform A, in Transform B)
+        {
+            return new Transform(Quaternion2D.InvRotateVector(A.Quaternion2D, Vector2.Subtract(B.Position, A.Position)), Quaternion2D.InvMulRot(A.Quaternion2D, B.Quaternion2D));
+        }
+
         // v2 = A.q' * (B.q * v1 + B.p - A.p)
         //    = A.q' * B.q * v1 + A.q' * (B.p - A.p)
+        [Pure]
         public static Transform MulT(in Transform A, in Transform B)
         {
             Transform C = new Transform
@@ -184,5 +210,51 @@ namespace Robust.Shared.Physics
             // TODO_ERIN optimize
             return new Quaternion2D(MathF.Cos(angle), MathF.Sin(angle));
         }
+
+        /// Rotate a vector
+        [Pure]
+        public static Vector2 RotateVector(Quaternion2D q, Vector2 v )
+        {
+            return new Vector2(q.C * v.X - q.S * v.Y, q.S * v.X + q.C * v.Y);
+        }
+
+        /// Inverse rotate a vector
+        [Pure]
+        public static Vector2 InvRotateVector(Quaternion2D q, Vector2 v)
+        {
+            return new Vector2(q.C * v.X + q.S * v.Y, -q.S * v.X + q.C * v.Y);
+        }
+
+        public bool IsValid()
+        {
+            if (float.IsNaN(S ) || float.IsNaN(C))
+            {
+                return false;
+            }
+
+            if (float.IsInfinity(S) || float.IsInfinity(C))
+            {
+                return false;
+            }
+
+            return IsNormalized();
+        }
+
+        public bool IsNormalized()
+        {
+            // larger tolerance due to failure on mingw 32-bit
+            float qq = S * S + C * C;
+            return 1.0f - 0.0006f < qq && qq < 1.0f + 0.0006f;
+        }
+
+        [Pure]
+        public static Quaternion2D InvMulRot(Quaternion2D q, Quaternion2D r)
+        {
+            // [ qc qs] * [rc -rs] = [qc*rc+qs*rs -qc*rs+qs*rc]
+            // [-qs qc]   [rs  rc]   [-qs*rc+qc*rs qs*rs+qc*rc]
+            // s(q - r) = qc * rs - qs * rc
+            // c(q - r) = qc * rc + qs * rs
+            return new Quaternion2D(q.C * r.C + q.S * r.S, q.C * r.S - q.S * r.C);
+        }
     }
 }

Robust.Shared/Prototypes/Attributes.cs

@@ -15,6 +15,9 @@ namespace Robust.Shared.Prototypes;
 [Virtual]
 public class PrototypeAttribute : Attribute
 {
+    /// <summary>
+    /// Override for the name of this kind of prototype. If not specified, this is automatically inferred via <see cref="PrototypeManager.CalculatePrototypeName"/>
+    /// </summary>
     public string? Type { get; internal set; }
     public readonly int LoadPriority = 1;
 
@@ -23,7 +26,7 @@ public class PrototypeAttribute : Attribute
         Type = type;
         LoadPriority = loadPriority;
     }
-    
+
     public PrototypeAttribute(int loadPriority)
     {
         Type = null;

Robust.Shared/Prototypes/PrototypeManager.cs

@@ -824,22 +824,10 @@ namespace Robust.Shared.Prototypes
         public bool TryGetKindFrom(Type type, [NotNullWhen(true)] out string? kind)
         {
             kind = null;
-
-            // If the type doesn't implement IPrototype, this fails.
-            if (!(typeof(IPrototype).IsAssignableFrom(type)))
+            if (!_kinds.TryGetValue(type, out var kindData))
                 return false;
 
-            var attribute = (PrototypeAttribute?)Attribute.GetCustomAttribute(type, typeof(PrototypeAttribute));
-
-            // If the prototype type doesn't have the attribute, this fails.
-            if (attribute == null)
-                return false;
-
-            // If the variant isn't registered, this fails.
-            if (attribute.Type == null || !HasKind(attribute.Type))
-                return false;
-
-            kind = attribute.Type;
+            kind = kindData.Name;
             return true;
         }
 
@@ -945,13 +933,13 @@ namespace Robust.Shared.Prototypes
                     "No " + nameof(PrototypeAttribute) + " to give it a type string.");
             }
 
-            attribute.Type ??= CalculatePrototypeName(kind);
+            var name = attribute.Type ?? CalculatePrototypeName(kind);
 
-            if (_kindNames.TryGetValue(attribute.Type, out var name))
+            if (_kindNames.TryGetValue(name, out var existing))
             {
                 throw new InvalidImplementationException(kind,
                     typeof(IPrototype),
-                    $"Duplicate prototype type ID: {attribute.Type}. Current: {name}");
+                    $"Duplicate prototype type ID: {attribute.Type}. Current: {existing}");
             }
 
             var foundIdAttribute = false;
@@ -1019,10 +1007,10 @@ namespace Robust.Shared.Prototypes
                     $"Did not find any member annotated with the {nameof(ParentDataFieldAttribute)} and/or {nameof(AbstractDataFieldAttribute)}");
             }
 
-            _kindNames[attribute.Type] = kind;
+            _kindNames[name] = kind;
             _kindPriorities[kind] = attribute.LoadPriority;
 
-            var kindData = new KindData(kind);
+            var kindData = new KindData(kind, name);
             kinds[kind] = kindData;
 
             if (kind.IsAssignableTo(typeof(IInheritingPrototype)))
@@ -1032,7 +1020,7 @@ namespace Robust.Shared.Prototypes
         /// <inheritdoc />
         public event Action<PrototypesReloadedEventArgs>? PrototypesReloaded;
 
-        private sealed class KindData(Type kind)
+        private sealed class KindData(Type kind, string name)
         {
             public Dictionary<string, IPrototype>? UnfrozenInstances;
 
@@ -1041,6 +1029,7 @@ namespace Robust.Shared.Prototypes
             public readonly Dictionary<string, MappingDataNode> Results = new();
 
             public readonly Type Type = kind;
+            public readonly string Name = name;
 
             // Only initialized if prototype is inheriting.
             public MultiRootInheritanceGraph<string>? Inheritance;

Robust.Shared/Resources/RsiLoading.cs

@@ -104,7 +104,7 @@ internal static class RsiLoading
             };
         }
 
-        return new RsiMetadata(size, states, textureParams);
+        return new RsiMetadata(size, states, textureParams, manifestJson.MetaAtlas);
     }
 
     public static void Warmup()
@@ -114,11 +114,12 @@ internal static class RsiLoading
         JsonSerializer.Deserialize<RsiJsonMetadata>(warmupJson, SerializerOptions);
     }
 
-    internal sealed class RsiMetadata(Vector2i size, StateMetadata[] states, TextureLoadParameters loadParameters)
+    internal sealed class RsiMetadata(Vector2i size, StateMetadata[] states, TextureLoadParameters loadParameters, bool metaAtlas)
     {
         public readonly Vector2i Size = size;
         public readonly StateMetadata[] States = states;
         public readonly TextureLoadParameters LoadParameters = loadParameters;
+        public readonly bool MetaAtlas = metaAtlas;
     }
 
     internal sealed class StateMetadata
@@ -140,7 +141,11 @@ internal static class RsiLoading
 
     // To be directly deserialized.
     [UsedImplicitly]
-    private sealed record RsiJsonMetadata(Vector2i Size, StateJsonMetadata[] States, RsiJsonLoad? Load);
+    private sealed record RsiJsonMetadata(
+        Vector2i Size,
+        StateJsonMetadata[] States,
+        RsiJsonLoad? Load,
+        bool MetaAtlas = true);
 
     [UsedImplicitly]
     private sealed record StateJsonMetadata(string Name, int? Directions, float[][]? Delays);

Robust.Shared/Serialization/Manager/SerializationManager.cs

@@ -70,7 +70,7 @@ namespace Robust.Shared.Serialization.Manager
                 {
                     foreach (var child in _reflectionManager.GetAllChildren(type))
                     {
-                        if (child.IsAbstract || child.IsGenericTypeDefinition)
+                        if (child.IsAbstract || child.IsGenericTypeDefinition || child.IsInterface)
                             continue;
 
                         yield return child;

Robust.Shared/Toolshed/Commands/Entities/WithCommand.cs

@@ -11,7 +11,6 @@ namespace Robust.Shared.Toolshed.Commands.Entities;
 internal sealed class WithCommand : ToolshedCommand
 {
     [Dependency] private readonly IComponentFactory _componentFactory = default!;
-    [Dependency] private readonly IPrototypeManager _prototype = default!;
 
     [CommandImplementation]
     public IEnumerable<EntityUid> With(

Robust.Shared/Toolshed/TypeParsers/BoolTypeParser.cs

@@ -35,7 +35,8 @@ public sealed class BoolTypeParser : TypeParser<bool>
             result = true;
             error = null;
             return true;
-        } else if (word == "false" || word == "f" || word == "0")
+        }
+        else if (word == "false" || word == "f" || word == "0")
         {
             result = false;
             error = null;
@@ -49,9 +50,9 @@ public sealed class BoolTypeParser : TypeParser<bool>
         }
     }
 
-    public override async ValueTask<(CompletionResult? result, IConError? error)> TryAutocomplete(ParserContext parserContext, string? argName)
+    public override ValueTask<(CompletionResult? result, IConError? error)> TryAutocomplete(ParserContext parserContext, string? argName)
     {
-        return (CompletionResult.FromOptions(new[] {"true", "false"}), null);
+        return new ValueTask<(CompletionResult?, IConError?)>((CompletionResult.FromOptions(new[] { "true", "false" }), null));
     }
 }
 

Robust.Shared/Toolshed/TypeParsers/EntityTypeParser.cs

@@ -38,10 +38,10 @@ internal sealed class EntityTypeParser : TypeParser<EntityUid>
         return true;
     }
 
-    public override async ValueTask<(CompletionResult? result, IConError? error)> TryAutocomplete(ParserContext parserContext,
+    public override ValueTask<(CompletionResult? result, IConError? error)> TryAutocomplete(ParserContext parserContext,
         string? argName)
     {
-        return (CompletionResult.FromHint("<NetEntity>"), null);
+        return new ValueTask<(CompletionResult?, IConError?)>((CompletionResult.FromHint("<NetEntity>"), null));
     }
 }
 

Robust.Shared/Toolshed/TypeParsers/EnumTypeParser.cs

@@ -11,7 +11,7 @@ using Robust.Shared.Utility;
 namespace Robust.Shared.Toolshed.TypeParsers;
 
 public sealed class EnumTypeParser<T> : TypeParser<T>
-    where T: unmanaged, Enum
+    where T : unmanaged, Enum
 {
     public override bool TryParse(ParserContext parserContext, [NotNullWhen(true)] out object? result,
         out IConError? error)
@@ -46,14 +46,14 @@ public sealed class EnumTypeParser<T> : TypeParser<T>
         return true;
     }
 
-    public override async ValueTask<(CompletionResult? result, IConError? error)> TryAutocomplete(ParserContext parserContext, string? argName)
+    public override ValueTask<(CompletionResult? result, IConError? error)> TryAutocomplete(ParserContext parserContext, string? argName)
     {
-        return (CompletionResult.FromOptions(Enum.GetNames<T>()), null);
+        return new ValueTask<(CompletionResult?, IConError?)>((CompletionResult.FromOptions(Enum.GetNames<T>()), null));
     }
 }
 
 public record InvalidEnum<T>(string Value) : IConError
-    where T: unmanaged, Enum
+    where T : unmanaged, Enum
 {
     public FormattedMessage DescribeInner()
     {

Robust.Shared/Toolshed/TypeParsers/SessionTypeParser.cs

@@ -43,11 +43,11 @@ internal sealed class SessionTypeParser : TypeParser<ICommonSession>
         return false;
     }
 
-    public override async ValueTask<(CompletionResult? result, IConError? error)> TryAutocomplete(ParserContext parserContext,
+    public override ValueTask<(CompletionResult? result, IConError? error)> TryAutocomplete(ParserContext parserContext,
         string? argName)
     {
         var opts = CompletionHelper.SessionNames(true, _player);
-        return (CompletionResult.FromHintOptions(opts, "<player session>"), null);
+        return new ValueTask<(CompletionResult?, IConError?)>((CompletionResult.FromHintOptions(opts, "<player session>"), null));
     }
 
     public record InvalidUsername(ILocalizationManager Loc, string Username) : IConError

Robust.UnitTesting/Client/GameObjects/Components/TransformComponentTests.cs

@@ -49,18 +49,18 @@ namespace Robust.UnitTesting.Client.GameObjects.Components
             var childTrans = entMan.GetComponent<TransformComponent>(child);
             ComponentHandleState handleState;
 
-            var compState = new TransformComponentState(new Vector2(5, 5), new Angle(0), entMan.GetNetEntity(gridIdB), false, false, true);
+            var compState = new TransformComponentState(new Vector2(5, 5), new Angle(0), entMan.GetNetEntity(gridIdB), false, false);
             handleState = new ComponentHandleState(compState, null);
             xformSystem.OnHandleState(parent, parentTrans, ref handleState);
 
-            compState = new TransformComponentState(new Vector2(6, 6), new Angle(0), entMan.GetNetEntity(gridIdB), false, false, true);
+            compState = new TransformComponentState(new Vector2(6, 6), new Angle(0), entMan.GetNetEntity(gridIdB), false, false);
             handleState = new ComponentHandleState(compState, null);
             xformSystem.OnHandleState(child, childTrans, ref handleState);
             // World pos should be 6, 6 now.
 
             // Act
             var oldWpos = xformSystem.GetWorldPosition(childTrans);
-            compState = new TransformComponentState(new Vector2(1, 1), new Angle(0), entMan.GetNetEntity(parent), false, false, true);
+            compState = new TransformComponentState(new Vector2(1, 1), new Angle(0), entMan.GetNetEntity(parent), false, false);
             handleState = new ComponentHandleState(compState, null);
             xformSystem.OnHandleState(child, childTrans, ref handleState);
             var newWpos = xformSystem.GetWorldPosition(childTrans);
@@ -98,15 +98,15 @@ namespace Robust.UnitTesting.Client.GameObjects.Components
             var node2Trans = entMan.GetComponent<TransformComponent>(node2);
             var node3Trans = entMan.GetComponent<TransformComponent>(node3);
 
-            var compState = new TransformComponentState(new Vector2(6, 6), Angle.FromDegrees(135), entMan.GetNetEntity(gridIdB), false, false, true);
+            var compState = new TransformComponentState(new Vector2(6, 6), Angle.FromDegrees(135), entMan.GetNetEntity(gridIdB), false, false);
             var handleState = new ComponentHandleState(compState, null);
             xformSystem.OnHandleState(node1, node1Trans, ref handleState);
 
-            compState = new TransformComponentState(new Vector2(1, 1), Angle.FromDegrees(45), entMan.GetNetEntity(node1), false, false, true);
+            compState = new TransformComponentState(new Vector2(1, 1), Angle.FromDegrees(45), entMan.GetNetEntity(node1), false, false);
             handleState = new ComponentHandleState(compState, null);
             xformSystem.OnHandleState(node2, node2Trans, ref handleState);
 
-            compState = new TransformComponentState(new Vector2(0, 0), Angle.FromDegrees(45), entMan.GetNetEntity(node2), false, false, true);
+            compState = new TransformComponentState(new Vector2(0, 0), Angle.FromDegrees(45), entMan.GetNetEntity(node2), false, false);
             handleState = new ComponentHandleState(compState, null);
             xformSystem.OnHandleState(node3, node3Trans, ref handleState);
 

Robust.UnitTesting/Shared/IoC/IoCManager_Test.cs

@@ -243,10 +243,12 @@ namespace Robust.UnitTesting.Shared.IoC
     {
         [Dependency]
 #pragma warning disable 649
+#pragma warning disable RA0032
         private readonly TestFieldInjection myself = default!;
 
         [Dependency]
         public TestFieldInjection myotherself = default!;
+#pragma warning restore RA0032
 #pragma warning restore 649
 
         public virtual void Test()

Robust.UnitTesting/Shared/Maths/Angle_Test.cs

@@ -27,6 +27,14 @@ namespace Robust.UnitTesting.Shared.Maths
             (0.92387953251128674f, -0.38268343236508978f, Direction.East, -System.Math.PI / 8.0)
         };
 
+        [Test]
+        public void TestAngleDegrees()
+        {
+            const double degrees = 75d;
+            var angle = Angle.FromDegrees(degrees);
+            Assert.That(angle.Degrees, Is.EqualTo(degrees));
+        }
+
         [Test]
         public void TestAngleZero()
         {

Robust.UnitTesting/Shared/Maths/Matrix3_Test.cs

@@ -12,18 +12,17 @@ namespace Robust.UnitTesting.Shared.Maths
     [TestOf(typeof(Matrix3x2))]
     public sealed class Matrix3_Test
     {
-        [Test]
-        public void GetRotationTest()
+        private static readonly TestCaseData[] Rotations = new TestCaseData[]
         {
-            Assert.That(Matrix3x2.Identity.Rotation(), Is.EqualTo(Angle.Zero));
+            new(Matrix3x2.Identity, Angle.Zero),
+            new(Matrix3x2.CreateRotation(MathF.PI / 2f), new Angle(Math.PI / 2)),
+            new(Matrix3x2.CreateRotation(MathF.PI), new Angle(Math.PI)),
+        };
 
-            var piOver2 = new Angle(Math.PI / 2);
-            var piOver2Mat = Matrix3Helpers.CreateRotation(piOver2.Theta);
-            Assert.That(piOver2Mat.Rotation(), Is.EqualTo(piOver2));
-
-            var pi = new Angle(Math.PI);
-            var piMat = Matrix3Helpers.CreateRotation(pi.Theta);
-            Assert.That(piMat.Rotation(), Is.EqualTo(pi));
+        [Test, TestCaseSource(nameof(Rotations))]
+        public void GetRotationTest(Matrix3x2 matrix, Angle angle)
+        {
+            Assert.That(angle, Is.EqualTo(matrix.Rotation()));
         }
 
         [Test]
@@ -35,7 +34,7 @@ namespace Robust.UnitTesting.Shared.Maths
             var origin = new Vector2(0, 0);
             var result = Vector2.Transform(origin, matrix);
 
-            Assert.That(control == result, Is.True, result.ToString);
+            Assert.That(control, Is.EqualTo(result), result.ToString);
         }
 
         private static readonly IEnumerable<(Vector2, double)> _rotationTests = new[]

Robust.UnitTesting/Shared/Physics/RayCast_Test.cs

@@ -0,0 +1,145 @@
+using System.Linq;
+using System.Numerics;
+using NUnit.Framework;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Map;
+using Robust.Shared.Maths;
+using Robust.Shared.Physics;
+using Robust.Shared.Physics.Collision.Shapes;
+using Robust.Shared.Physics.Components;
+using Robust.Shared.Physics.Dynamics;
+using Robust.Shared.Physics.Shapes;
+using Robust.Shared.Physics.Systems;
+using Robust.UnitTesting.Server;
+
+namespace Robust.UnitTesting.Shared.Physics;
+
+[TestFixture]
+public sealed class RayCast_Test
+{
+    private static TestCaseData[] _rayCases =
+    {
+        // Ray goes through
+        new(new Vector2(0f, 0.5f), Vector2.UnitY * 2f, new Vector2(0f, 1f - PhysicsConstants.PolygonRadius)),
+
+        // Ray stops inside
+        new(new Vector2(0f, 0.5f), Vector2.UnitY, new Vector2(0f, 1f - PhysicsConstants.PolygonRadius)),
+
+        // Ray starts inside
+        new(new Vector2(0f, 1.5f), Vector2.UnitY, null),
+
+        // No hit
+        new(new Vector2(0f, 0.5f), -Vector2.UnitY, null),
+    };
+
+    private static TestCaseData[] _shapeCases =
+    {
+        // Circle
+        // - Initial overlap, no shapecast
+        new(new PhysShapeCircle(0.5f, Vector2.Zero), new Transform(Vector2.UnitY / 2f, Angle.Zero), Vector2.UnitY, null),
+
+        // - Cast
+        new(new PhysShapeCircle(0.5f, Vector2.Zero), new Transform(Vector2.Zero, Angle.Zero), Vector2.UnitY, new Vector2(0f, 1f - PhysicsConstants.PolygonRadius)),
+
+        // - Miss
+        new(new PhysShapeCircle(0.5f, Vector2.Zero), new Transform(Vector2.Zero, Angle.Zero), -Vector2.UnitY, null),
+
+        // Polygon
+        // - Initial overlap, no shapecast
+        new(new Polygon(Box2.UnitCentered), new Transform(Vector2.UnitY / 2f, Angle.Zero), Vector2.UnitY, null),
+
+        // - Cast
+        new(new Polygon(Box2.UnitCentered), new Transform(Vector2.Zero, Angle.Zero), Vector2.UnitY, new Vector2(0.5f, 1f - PhysicsConstants.PolygonRadius)),
+
+        // - Miss
+        new(new Polygon(Box2.UnitCentered), new Transform(Vector2.Zero, Angle.Zero), -Vector2.UnitY, null),
+    };
+
+    [Test, TestCaseSource(nameof(_rayCases))]
+    public void RayCast(Vector2 origin, Vector2 direction, Vector2? point)
+    {
+        var sim = RobustServerSimulation.NewSimulation().RegisterEntitySystems(f =>
+        {
+            f.LoadExtraSystemType<RayCastSystem>();
+        }).InitializeInstance();
+        Setup(sim, out var mapId);
+        var raycast = sim.System<RayCastSystem>();
+
+        var hits = raycast.CastRayClosest(mapId,
+            origin,
+            direction,
+            new QueryFilter()
+            {
+                LayerBits = 1,
+            });
+
+        if (point == null)
+        {
+            Assert.That(!hits.Hit);
+        }
+        else
+        {
+            Assert.That(hits.Results.First().Point, Is.EqualTo(point.Value));
+        }
+    }
+
+    [Test, TestCaseSource(nameof(_shapeCases))]
+    public void ShapeCast(IPhysShape shape, Transform origin, Vector2 direction, Vector2? point)
+    {
+        var sim = RobustServerSimulation.NewSimulation().RegisterEntitySystems(f =>
+        {
+            f.LoadExtraSystemType<RayCastSystem>();
+        }).InitializeInstance();
+        Setup(sim, out var mapId);
+        var raycast = sim.System<RayCastSystem>();
+
+        var hits = raycast.CastShape(mapId,
+            shape,
+            origin,
+            direction,
+            new QueryFilter()
+            {
+                LayerBits = 1,
+            },
+            RayCastSystem.RayCastAllCallback);
+
+        if (point == null)
+        {
+            Assert.That(!hits.Hit);
+        }
+        else
+        {
+            Assert.That(hits.Results.First().Point, Is.EqualTo(point.Value));
+        }
+    }
+
+    private void Setup(ISimulation sim, out MapId mapId)
+    {
+        var entManager = sim.Resolve<IEntityManager>();
+        var mapSystem = entManager.System<SharedMapSystem>();
+
+        sim.System<SharedMapSystem>().CreateMap(out mapId);
+
+        var grid = sim.Resolve<IMapManager>().CreateGridEntity(mapId);
+
+        for (var i = 0; i < 3; i++)
+        {
+            mapSystem.SetTile(grid, new Vector2i(i, 0), new Tile(1));
+        }
+
+        // Spawn a wall in the middle tile.
+        var wall = entManager.SpawnEntity(null, new EntityCoordinates(grid.Owner, new Vector2(1.5f, 0.5f)));
+
+        var physics = entManager.AddComponent<PhysicsComponent>(wall);
+        var poly = new PolygonShape();
+        poly.SetAsBox(Box2.UnitCentered);
+        entManager.System<FixtureSystem>().CreateFixture(wall, "fix1", new Fixture(poly, 1, 1, true));
+
+        entManager.System<SharedPhysicsSystem>().SetCanCollide(wall, true, body: physics);
+        Assert.That(physics.CanCollide);
+
+        // Rotate it to be vertical
+        entManager.System<SharedTransformSystem>().SetLocalRotation(grid.Owner, Angle.FromDegrees(90));
+        entManager.System<SharedTransformSystem>().SetLocalPosition(grid.Owner, Vector2.UnitX / 2f);
+    }
+}

Robust.UnitTesting/Shared/Serialization/SerializationTests/CommunitaryLungTest.cs

@@ -17,14 +17,18 @@ public sealed partial class CommunitaryLungTest : SerializationTest
         Assert.That(def.Dict == copy.Dict, Is.False);
 
         // Sanity check
+#pragma warning disable CS1718 // Comparison made to same variable
         Assert.That(def.Dict == def.Dict, Is.True);
+#pragma warning restore CS1718 // Comparison made to same variable
 
         Serialization.CopyTo(def, ref copy, notNullableOverride: true);
 
         Assert.That(def.Dict == copy.Dict, Is.False);
 
         // Sanity check
+#pragma warning disable CS1718 // Comparison made to same variable
         Assert.That(def.Dict == def.Dict, Is.True);
+#pragma warning restore CS1718 // Comparison made to same variable
     }
 
     [Test]
@@ -38,7 +42,9 @@ public sealed partial class CommunitaryLungTest : SerializationTest
         Assert.That(copy.Dict, Is.Not.Null);
 
         // Sanity check
+#pragma warning disable CS1718 // Comparison made to same variable
         Assert.That(def.Dict == def.Dict, Is.True);
+#pragma warning restore CS1718 // Comparison made to same variable
 
         Serialization.CopyTo(def, ref copy, notNullableOverride: true);
 
@@ -46,7 +52,9 @@ public sealed partial class CommunitaryLungTest : SerializationTest
         Assert.That(copy.Dict, Is.Not.Null);
 
         // Sanity check
+#pragma warning disable CS1718 // Comparison made to same variable
         Assert.That(def.Dict == def.Dict, Is.True);
+#pragma warning restore CS1718 // Comparison made to same variable
     }
 
     [Test]

Robust.UnitTesting/Shared/Serialization/TypeSerializers/AngleSerializerTest.cs

@@ -1,4 +1,5 @@
-using System.Globalization;
+using System;
+using System.Globalization;
 using NUnit.Framework;
 using Robust.Shared.Maths;
 using Robust.Shared.Serialization.Manager;
@@ -11,24 +12,46 @@ namespace Robust.UnitTesting.Shared.Serialization.TypeSerializers
     [TestOf(typeof(AngleSerializer))]
     public sealed class AngleSerializerTest : SerializationTest
     {
-        [Test]
-        public void SerializationTest()
+        private static readonly TestCaseData[] _source = new[]
         {
-            var degrees = 75d;
-            var angle = Angle.FromDegrees(degrees);
+            new TestCaseData(Math.PI),
+            new TestCaseData(Math.PI / 2),
+            new TestCaseData(Math.PI / 4),
+            new TestCaseData(0.515),
+            new TestCaseData(75),
+        };
+
+        [Test, TestCaseSource(nameof(_source))]
+        public void SerializationRadsTest(double radians)
+        {
+            var angle = new Angle(radians);
             var node = Serialization.WriteValueAs<ValueDataNode>(angle);
-            var serializedValue = $"{MathHelper.DegreesToRadians(degrees).ToString(CultureInfo.InvariantCulture)} rad";
+            var serializedValue = $"{radians.ToString(CultureInfo.InvariantCulture)} rad";
 
             Assert.That(node.Value, Is.EqualTo(serializedValue));
         }
 
-        [Test]
-        public void DeserializationTest()
+        [Test, TestCaseSource(nameof(_source))]
+        public void DeserializationRadsTest(double radians)
         {
-            var degrees = 75;
-            var node = new ValueDataNode(degrees.ToString());
+            var angle = new Angle(radians);
+            var node = new ValueDataNode($"{radians.ToString(CultureInfo.InvariantCulture)} rad");
             var deserializedAngle = Serialization.Read<Angle>(node);
+
+            Assert.That(deserializedAngle, Is.EqualTo(angle));
+        }
+
+        /*
+         * Serialization of degrees test won't work because it's comparing degrees to radians.
+         */
+
+        [Test, TestCaseSource(nameof(_source))]
+        public void DeserializationDegreesTest(double radians)
+        {
+            var degrees = MathHelper.RadiansToDegrees(radians);
             var angle = Angle.FromDegrees(degrees);
+            var node = new ValueDataNode($"{degrees.ToString(CultureInfo.InvariantCulture)}");
+            var deserializedAngle = Serialization.Read<Angle>(node);
 
             Assert.That(deserializedAngle, Is.EqualTo(angle));
         }