v0.8.77

It now includes the invalid hexcode argument.
Something in content kept getting these exceptions on prod and knowing the invalid argument would be very helpful when debugging these in the future.

.github/CODEOWNERS

@@ -11,7 +11,7 @@
 /Robust.Analyzers @PaulRitter
 /Robust.*/GameStates @PaulRitter
 /Robust.Shared/Analyzers @PaulRitter
-/Robust.*/Serialization @PaulRitter
+/Robust.*/Serialization @PaulRitter @DrSmugleaf
 /Robust.*/Prototypes @PaulRitter
 /Robust.Shared/GameObjects/ComponentDependencies @PaulRitter
 /Robust.*/Containers @PaulRitter

.github/workflows/build-docfx.yml

@@ -0,0 +1,34 @@
+name: Build & Publish DocFX
+
+on:
+  schedule:
+    - cron: "0 0 * * 0"
+jobs:
+  docfx:
+   runs-on: ubuntu-latest
+   steps: 
+    - uses: actions/checkout@v2
+      with:
+        submodules: true
+
+    - name: Setup .NET Core
+      uses: actions/setup-dotnet@v1
+      with:
+        dotnet-version: 6.0.x
+        
+    - name: Install dependencies
+      run: dotnet restore
+      
+    - 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: 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

@@ -22,10 +22,12 @@ jobs:
     - name: Setup .NET Core
       uses: actions/setup-dotnet@v1
       with:
-        dotnet-version: 6.0.100
+        dotnet-version: 6.0.x
     - name: Install dependencies
       run: dotnet restore
     - name: Build
       run: dotnet build --no-restore /p:WarningsAsErrors=nullable
     - name: Test Engine
       run: dotnet test --no-build Robust.UnitTesting/Robust.UnitTesting.csproj -v n
+ 
+

.gitignore

@@ -76,3 +76,5 @@ MSBuild/Robust.Custom.targets
 
 
 release/
+Robust.Docfx/*-site
+Robust.Docfx/api

MSBuild/Robust.Engine.Version.props

@@ -1,4 +1,4 @@
 <Project>
     <!-- This file automatically reset by Tools/version.py -->
-    <PropertyGroup><Version>0.8.52</Version></PropertyGroup>
+    <PropertyGroup><Version>0.8.77</Version></PropertyGroup>
 </Project>

Robust.Analyzers/Robust.Analyzers.csproj

@@ -6,9 +6,9 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.8.0" PrivateAssets="all" />
-    <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.2" PrivateAssets="all" />
-    <PackageReference Include="Microsoft.CodeAnalysis.Workspaces.Common" Version="3.8.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.0.1" PrivateAssets="all" />
+    <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.3" PrivateAssets="all" />
+    <PackageReference Include="Microsoft.CodeAnalysis.Workspaces.Common" Version="4.0.1" />
   </ItemGroup>
 
 </Project>

Robust.Client.Injectors/Robust.Client.Injectors.csproj

@@ -6,7 +6,7 @@
     </PropertyGroup>
 
     <ItemGroup>
-      <PackageReference Include="Microsoft.Build.Framework" Version="16.8.0" />
+      <PackageReference Include="Microsoft.Build.Framework" Version="17.0.0" />
       <PackageReference Include="Mono.Cecil" Version="0.11.3" />
       <PackageReference Include="Pidgin" Version="2.5.0" />
     </ItemGroup>

Robust.Client.NameGenerator/Robust.Client.NameGenerator.csproj

@@ -5,8 +5,8 @@
     </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.8.0" PrivateAssets="all" />
-    <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.2" PrivateAssets="all" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.0.1" PrivateAssets="all" />
+    <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.3" PrivateAssets="all" />
   </ItemGroup>
 
   <ItemGroup>

Robust.Client/BaseClient.cs

@@ -26,7 +26,6 @@ namespace Robust.Client
         [Dependency] private readonly IPlayerManager _playMan = default!;
         [Dependency] private readonly INetConfigurationManager _configManager = default!;
         [Dependency] private readonly IClientEntityManager _entityManager = default!;
-        [Dependency] private readonly IEntityLookup _entityLookup = default!;
         [Dependency] private readonly IMapManager _mapManager = default!;
         [Dependency] private readonly IDiscordRichPresence _discord = default!;
         [Dependency] private readonly IGameTiming _timing = default!;
@@ -213,7 +212,6 @@ namespace Robust.Client
         {
             _entityManager.Startup();
             _mapManager.Startup();
-            _entityLookup.Startup();
 
             _timing.ResetSimTime();
             _timing.Paused = false;
@@ -224,7 +222,6 @@ namespace Robust.Client
             IoCManager.Resolve<INetConfigurationManager>().FlushMessages();
             _gameStates.Reset();
             _playMan.Shutdown();
-            _entityLookup.Shutdown();
             _entityManager.Shutdown();
             _mapManager.Shutdown();
             _discord.ClearPresence();

Robust.Client/ClientIoC.cs

@@ -47,7 +47,6 @@ namespace Robust.Client
             IoCManager.Register<IMapManagerInternal, NetworkedMapManager>();
             IoCManager.Register<INetworkedMapManager, NetworkedMapManager>();
             IoCManager.Register<IEntityManager, ClientEntityManager>();
-            IoCManager.Register<IEntityLookup, EntityLookup>();
             IoCManager.Register<IReflectionManager, ClientReflectionManager>();
             IoCManager.Register<IConsoleHost, ClientConsoleHost>();
             IoCManager.Register<IClientConsoleHost, ClientConsoleHost>();
@@ -72,7 +71,6 @@ namespace Robust.Client
             IoCManager.Register<IStateManager, StateManager>();
             IoCManager.Register<IUserInterfaceManager, UserInterfaceManager>();
             IoCManager.Register<IUserInterfaceManagerInternal, UserInterfaceManager>();
-            IoCManager.Register<IDebugDrawing, DebugDrawing>();
             IoCManager.Register<ILightManager, LightManager>();
             IoCManager.Register<IDiscordRichPresence, DiscordRichPresence>();
             IoCManager.Register<IMidiManager, MidiManager>();

Robust.Client/Console/ClientConsoleHost.cs

@@ -109,13 +109,13 @@ namespace Robust.Client.Console
             if (AvailableCommands.ContainsKey(commandName))
             {
                 var playerManager = IoCManager.Resolve<IPlayerManager>();
-
+#if !DEBUG
                 if (!_conGroup.CanCommand(commandName) && playerManager.LocalPlayer?.Session.Status > SessionStatus.Connecting)
                 {
                     WriteError(null, $"Insufficient perms for command: {commandName}");
                     return;
                 }
-
+#endif
                 var command1 = AvailableCommands[commandName];
                 args.RemoveAt(0);
                 var shell = new ConsoleShell(this, null);

Robust.Client/Console/Commands/Debug.cs

@@ -168,7 +168,7 @@ namespace Robust.Client.Console.Commands
 
         public void Execute(IConsoleShell shell, string argStr, string[] args)
         {
-            var mgr = IoCManager.Resolve<IDebugDrawing>();
+            var mgr = EntitySystem.Get<DebugDrawingSystem>();
             mgr.DebugPositions = !mgr.DebugPositions;
         }
     }
@@ -861,7 +861,7 @@ namespace Robust.Client.Console.Commands
             var chunkIndex = grid.LocalToChunkIndices(grid.MapToGrid(mousePos));
             var chunk = internalGrid.GetChunk(chunkIndex);
 
-            shell.WriteLine($"worldBounds: {chunk.CalcWorldAABB()} localBounds: {chunk.CalcLocalBounds()}");
+            shell.WriteLine($"worldBounds: {internalGrid.CalcWorldAABB(chunk)} localBounds: {chunk.CachedBounds}");
         }
     }
 

Robust.Client/Debugging/DebugDrawingSystem.cs

@@ -6,17 +6,21 @@ using Robust.Shared.Maths;
 
 namespace Robust.Client.Debugging
 {
-    /// <inheritdoc />
-    public sealed class DebugDrawing : IDebugDrawing
+    /// <summary>
+    /// A collection of visual debug overlays for the client game.
+    /// </summary>
+    public sealed class DebugDrawingSystem : EntitySystem
     {
         [Dependency] private readonly IOverlayManager _overlayManager = default!;
         [Dependency] private readonly IEyeManager _eyeManager = default!;
-        [Dependency] private readonly IEntityLookup _lookup = default!;
         [Dependency] private readonly IEntityManager _entityManager = default!;
+        [Dependency] private readonly EntityLookupSystem _lookup = default!;
 
         private bool _debugPositions;
 
-        /// <inheritdoc />
+        /// <summary>
+        /// Toggles the visual overlay of the local origin for each entity on screen.
+        /// </summary>
         public bool DebugPositions
         {
             get => _debugPositions;
@@ -42,13 +46,13 @@ namespace Robust.Client.Debugging
 
         private sealed class EntityPositionOverlay : Overlay
         {
-            private readonly IEntityLookup _lookup;
+            private readonly EntityLookupSystem _lookup;
             private readonly IEyeManager _eyeManager;
             private readonly IEntityManager _entityManager;
 
             public override OverlaySpace Space => OverlaySpace.WorldSpace;
 
-            public EntityPositionOverlay(IEntityLookup lookup, IEyeManager eyeManager, IEntityManager entityManager)
+            public EntityPositionOverlay(EntityLookupSystem lookup, IEyeManager eyeManager, IEntityManager entityManager)
             {
                 _lookup = lookup;
                 _eyeManager = eyeManager;
@@ -61,13 +65,11 @@ namespace Robust.Client.Debugging
 
                 var worldHandle = (DrawingHandleWorld) args.DrawingHandle;
                 var viewport = _eyeManager.GetWorldViewport();
+                var xformQuery = _entityManager.GetEntityQuery<TransformComponent>();
 
                 foreach (var entity in _lookup.GetEntitiesIntersecting(_eyeManager.CurrentMap, viewport))
                 {
-                    var transform = _entityManager.GetComponent<TransformComponent>(entity);
-
-                    var center = transform.WorldPosition;
-                    var worldRotation = transform.WorldRotation;
+                    var (center, worldRotation) = xformQuery.GetComponent(entity).GetWorldPositionRotation();
 
                     var xLine = worldRotation.RotateVec(Vector2.UnitX);
                     var yLine = worldRotation.RotateVec(Vector2.UnitY);

Robust.Client/Debugging/IDebugDrawing.cs

@@ -1,13 +0,0 @@
-namespace Robust.Client.Debugging
-{
-    /// <summary>
-    /// A collection of visual debug overlays for the client game.
-    /// </summary>
-    public interface IDebugDrawing
-    {
-        /// <summary>
-        /// Toggles the visual overlay of the local origin for each entity on screen.
-        /// </summary>
-        bool DebugPositions { get; set; }
-    }
-}

Robust.Client/GameController/GameController.cs

@@ -50,7 +50,6 @@ namespace Robust.Client
         [Dependency] private readonly IClientConsoleHost _console = default!;
         [Dependency] private readonly ITimerManager _timerManager = default!;
         [Dependency] private readonly IClientEntityManager _entityManager = default!;
-        [Dependency] private readonly IEntityLookup _lookup = default!;
         [Dependency] private readonly IPlacementManager _placementManager = default!;
         [Dependency] private readonly IClientGameStateManager _gameStateManager = default!;
         [Dependency] private readonly IOverlayManagerInternal _overlayManager = default!;
@@ -455,6 +454,7 @@ namespace Robust.Client
         private void Tick(FrameEventArgs frameEventArgs)
         {
             _modLoader.BroadcastUpdate(ModUpdateLevel.PreEngine, frameEventArgs);
+            _console.CommandBufferExecute();
             _timerManager.UpdateTimers(frameEventArgs);
             _taskManager.ProcessPendingTasks();
 
@@ -470,7 +470,6 @@ namespace Robust.Client
                 // The last real tick is the current tick! This way we won't be in "prediction" mode.
                 _gameTiming.LastRealTick = _gameTiming.CurTick;
                 _entityManager.TickUpdate(frameEventArgs.DeltaSeconds, noPredictions: false);
-                _lookup.Update();
             }
 
             _modLoader.BroadcastUpdate(ModUpdateLevel.PostEngine, frameEventArgs);
@@ -510,7 +509,7 @@ namespace Robust.Client
             logManager.GetSawmill("discord").Level = LogLevel.Warning;
             logManager.GetSawmill("net.predict").Level = LogLevel.Info;
             logManager.GetSawmill("szr").Level = LogLevel.Info;
-            logManager.GetSawmill("loc").Level = LogLevel.Error;
+            logManager.GetSawmill("loc").Level = LogLevel.Warning;
 
 #if DEBUG_ONLY_FCE_INFO
 #if DEBUG_ONLY_FCE_LOG
@@ -575,7 +574,6 @@ namespace Robust.Client
 
             _networkManager.Shutdown("Client shutting down");
             _midiManager.Shutdown();
-            IoCManager.Resolve<IEntityLookup>().Shutdown();
             _entityManager.Shutdown();
             _clyde.Shutdown();
             _clydeAudio.Shutdown();

Robust.Client/GameObjects/Components/Light/ClientOccluderComponent.cs

@@ -8,7 +8,7 @@ using Robust.Shared.ViewVariables;
 namespace Robust.Client.GameObjects
 {
     [ComponentReference(typeof(OccluderComponent))]
-    internal sealed class ClientOccluderComponent : OccluderComponent
+    public sealed class ClientOccluderComponent : OccluderComponent
     {
         [Dependency] private readonly IMapManager _mapManager = default!;
         [Dependency] private readonly IEntityManager _entityManager = default!;
@@ -71,13 +71,29 @@ namespace Robust.Client.GameObjects
         {
             Occluding = OccluderDir.None;
 
-            if (Deleted || !_entityManager.GetComponent<TransformComponent>(Owner).Anchored)
+            if (Deleted)
+                return;
+
+            // Content may want to override the default behavior for occlusion.
+            var xform = _entityManager.GetComponent<TransformComponent>(Owner);
+            var ev = new OccluderDirectionsEvent
             {
+                Component = xform,
+            };
+
+            _entityManager.EventBus.RaiseLocalEvent(Owner, ref ev);
+
+            if (ev.Handled)
+            {
+                Occluding = ev.Directions;
                 return;
             }
 
-            var grid = _mapManager.GetGrid(_entityManager.GetComponent<TransformComponent>(Owner).GridID);
-            var position = _entityManager.GetComponent<TransformComponent>(Owner).Coordinates;
+            if (!xform.Anchored)
+                return;
+
+            var grid = _mapManager.GetGrid(xform.GridID);
+            var position = xform.Coordinates;
             void CheckDir(Direction dir, OccluderDir oclDir)
             {
                 foreach (var neighbor in grid.GetInDir(position, dir))
@@ -90,7 +106,7 @@ namespace Robust.Client.GameObjects
                 }
             }
 
-            var angle = _entityManager.GetComponent<TransformComponent>(Owner).LocalRotation;
+            var angle = xform.LocalRotation;
             var dirRolling = angle.GetCardinalDir();
             // dirRolling starts at effective south
 
@@ -105,15 +121,28 @@ namespace Robust.Client.GameObjects
 
             CheckDir(dirRolling, OccluderDir.East);
         }
+    }
 
-        [Flags]
-        internal enum OccluderDir : byte
-        {
-            None = 0,
-            North = 1,
-            East = 1 << 1,
-            South = 1 << 2,
-            West = 1 << 3,
-        }
+    [Flags]
+    public enum OccluderDir : byte
+    {
+        None = 0,
+        North = 1,
+        East = 1 << 1,
+        South = 1 << 2,
+        West = 1 << 3,
+    }
+
+    /// <summary>
+    /// Raised by occluders when trying to get occlusion directions.
+    /// </summary>
+    [ByRefEvent]
+    public struct OccluderDirectionsEvent
+    {
+        public bool Handled = false;
+        public OccluderDir Directions = OccluderDir.None;
+        public TransformComponent Component = default!;
+
+        public OccluderDirectionsEvent() {}
     }
 }

Robust.Client/GameObjects/Components/Renderable/ISpriteComponent.cs

@@ -119,7 +119,8 @@ namespace Robust.Client.GameObjects
         ///     This is useful to allow layer map configs to be defined in prototypes,
         ///     while still allowing code to create configs if they're absent.
         /// </remarks>
-        void LayerMapReserveBlank(object key);
+        /// <returns>Index of the new layer.</returns>
+        int LayerMapReserveBlank(object key);
 
         /// <summary>
         ///     Adds a layer without texture (thus falling back to the error texture).
@@ -145,8 +146,8 @@ namespace Robust.Client.GameObjects
         void RemoveLayer(int layer);
         void RemoveLayer(object layerKey);
 
-        void LayerSetShader(int layer, ShaderInstance shader);
-        void LayerSetShader(object layerKey, ShaderInstance shader);
+        void LayerSetShader(int layer, ShaderInstance shader, string? prototype = null);
+        void LayerSetShader(object layerKey, ShaderInstance shader, string? prototype = null);
         void LayerSetShader(int layer, string shaderName);
         void LayerSetShader(object layerKey, string shaderName);
 
@@ -217,8 +218,8 @@ namespace Robust.Client.GameObjects
         int GetLayerDirectionCount(ISpriteLayer layer);
 
         /// <summary>
-        ///     Calculate sprite bounding box in world-space coordinates.
+        ///     Calculate the rotated sprite bounding box in world-space coordinates.
         /// </summary>
-        Box2 CalculateBoundingBox(Vector2 worldPos);
+        Box2Rotated CalculateRotatedBoundingBox(Vector2 worldPosition, Angle worldRotation, IEye? eye = null);
     }
 }

Robust.Client/GameObjects/Components/Renderable/ISpriteLayer.cs

@@ -25,8 +25,6 @@ namespace Robust.Client.GameObjects
 
         RSI.State.Direction EffectiveDirection(Angle worldRotation);
 
-        Vector2 LocalToLayer(Vector2 localPos);
-
         /// <summary>
         ///     Layer size in pixels.
         ///     Don't account layer scale or sprite world transform.
@@ -37,6 +35,6 @@ namespace Robust.Client.GameObjects
         ///     Calculate layer bounding box in sprite local-space coordinates.
         /// </summary>
         /// <returns>Bounding box in sprite local-space coordinates.</returns>
-        Box2 CalculateBoundingBox();
+        Box2 CalculateBoundingBox(Angle worldAngle);
     }
 }

Robust.Client/GameObjects/Components/Renderable/SpriteBoundsOverlay.cs

@@ -84,10 +84,16 @@ namespace Robust.Client.GameObjects
 
                 foreach (var sprite in comp.SpriteTree.QueryAabb(localAABB))
                 {
-                    var worldPos = _entityManager.GetComponent<TransformComponent>(sprite.Owner).WorldPosition;
-                    var bounds = sprite.CalculateBoundingBox(worldPos);
+                    var (worldPos, worldRot) = _entityManager.GetComponent<TransformComponent>(sprite.Owner).GetWorldPositionRotation();
+                    var bounds = sprite.CalculateRotatedBoundingBox(worldPos, worldRot);
+
+                    // Get scaled down bounds used to indicate the "south" of a sprite.
+                    var localBound = bounds.Box;
+                    var smallLocal = localBound.Scale(0.2f).Translated(-new Vector2(0f, localBound.Extents.Y));
+                    var southIndicator = new Box2Rotated(smallLocal, bounds.Rotation, bounds.Origin);
+
                     handle.DrawRect(bounds, Color.Red.WithAlpha(0.2f));
-                    handle.DrawRect(bounds.Scale(0.2f).Translated(-new Vector2(0f, bounds.Extents.Y)), Color.Blue.WithAlpha(0.5f));
+                    handle.DrawRect(southIndicator, Color.Blue.WithAlpha(0.5f));
                 }
             }
         }

Robust.Client/GameObjects/Components/Renderable/SpriteComponent.cs

@@ -20,6 +20,7 @@ using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom;
 using Robust.Shared.Utility;
 using Robust.Shared.ViewVariables;
 using DrawDepthTag = Robust.Shared.GameObjects.DrawDepth;
+using RSIDirection = Robust.Client.Graphics.RSI.State.Direction;
 
 namespace Robust.Client.GameObjects
 {
@@ -31,6 +32,8 @@ namespace Robust.Client.GameObjects
         [Dependency] private readonly IResourceCache resourceCache = default!;
         [Dependency] private readonly IPrototypeManager prototypes = default!;
         [Dependency] private readonly IEntityManager entities = default!;
+        [Dependency] private readonly IReflectionManager reflection = default!;
+        [Dependency] private readonly IEyeManager eyeManager = default!;
 
         [DataField("visible")]
         private bool _visible = true;
@@ -72,7 +75,11 @@ namespace Robust.Client.GameObjects
         public Vector2 Scale
         {
             get => scale;
-            set => scale = value;
+            set
+            {
+                scale = value;
+                UpdateLocalMatrix();
+            }
         }
 
         [DataField("rotation")]
@@ -83,7 +90,11 @@ namespace Robust.Client.GameObjects
         public Angle Rotation
         {
             get => rotation;
-            set => rotation = value;
+            set
+            {
+                rotation = value;
+                UpdateLocalMatrix();
+            }
         }
 
         [DataField("offset")]
@@ -97,12 +108,18 @@ namespace Robust.Client.GameObjects
         public Vector2 Offset
         {
             get => offset;
-            set => offset = value;
+            set
+            {
+                offset = value;
+                UpdateLocalMatrix();
+            }
         }
 
         [DataField("color")]
         private Color color = Color.White;
 
+        public Matrix3 LocalMatrix = Matrix3.Identity;
+
         [Animatable]
         [ViewVariables(VVAccess.ReadWrite)]
         public Color Color
@@ -134,113 +151,7 @@ namespace Robust.Client.GameObjects
                 Layers.Clear();
                 foreach (var layerDatum in value)
                 {
-                    var anyTextureAttempted = false;
-                    var layer = new Layer(this);
-                    if (!string.IsNullOrWhiteSpace(layerDatum.RsiPath))
-                    {
-                        var path = TextureRoot / layerDatum.RsiPath;
-
-                        if (IoCManager.Resolve<IResourceCache>().TryGetResource(path, out RSIResource? resource))
-                        {
-                            layer.RSI = resource.RSI;
-                        }
-                        else
-                        {
-                            Logger.ErrorS(LogCategory, "Unable to load layer RSI '{0}'.", path);
-                        }
-                    }
-
-                    if (!string.IsNullOrWhiteSpace(layerDatum.State))
-                    {
-                        anyTextureAttempted = true;
-                        var theRsi = layer.RSI ?? BaseRSI;
-                        if (theRsi == null)
-                        {
-                            Logger.ErrorS(LogCategory,
-                                "Layer has no RSI to load states from. Cannot use 'state' property. ({0})",
-                                layerDatum.State);
-                        }
-                        else
-                        {
-                            var stateid = new RSI.StateId(layerDatum.State);
-                            layer.State = stateid;
-                            if (theRsi.TryGetState(stateid, out var state))
-                            {
-                                // Always use south because this layer will be cached in the serializer.
-                                layer.AnimationTimeLeft = state.GetDelay(0);
-                            }
-                            else
-                            {
-                                Logger.ErrorS(LogCategory,
-                                    $"State '{stateid}' not found in RSI: '{theRsi.Path}'.",
-                                    stateid);
-                            }
-                        }
-                    }
-
-                    if (!string.IsNullOrWhiteSpace(layerDatum.TexturePath))
-                    {
-                        anyTextureAttempted = true;
-                        if (layer.State.IsValid)
-                        {
-                            Logger.ErrorS(LogCategory,
-                                "Cannot specify 'texture' on a layer if it has an RSI state specified."
-                            );
-                        }
-                        else
-                        {
-                            layer.Texture =
-                                IoCManager.Resolve<IResourceCache>().GetResource<TextureResource>(TextureRoot / layerDatum.TexturePath);
-                        }
-                    }
-
-                    if (!string.IsNullOrWhiteSpace(layerDatum.Shader))
-                    {
-                        if (IoCManager.Resolve<IPrototypeManager>().TryIndex<ShaderPrototype>(layerDatum.Shader, out var prototype))
-                        {
-                            layer.Shader = prototype.Instance();
-                        }
-                        else
-                        {
-                            Logger.ErrorS(LogCategory,
-                                "Shader prototype '{0}' does not exist.",
-                                layerDatum.Shader);
-                        }
-                    }
-
-                    layer.Color = layerDatum.Color;
-                    layer.Rotation = layerDatum.Rotation;
-                    layer._offset = layerDatum.Offset;
-                    // If neither state: nor texture: were provided we assume that they want a blank invisible layer.
-                    layer.Visible = anyTextureAttempted && layerDatum.Visible;
-                    layer.Scale = layerDatum.Scale;
-
-                    Layers.Add(layer);
-
-                    if (layerDatum.MapKeys != null)
-                    {
-                        var index = Layers.Count - 1;
-                        foreach (var keyString in layerDatum.MapKeys)
-                        {
-                            object key;
-                            if (IoCManager.Resolve<IReflectionManager>().TryParseEnumReference(keyString, out var @enum))
-                            {
-                                key = @enum;
-                            }
-                            else
-                            {
-                                key = keyString;
-                            }
-
-                            if (LayerMap.ContainsKey(key))
-                            {
-                                Logger.ErrorS(LogCategory, "Duplicate layer map key definition: {0}", key);
-                                continue;
-                            }
-
-                            LayerMap.Add(key, index);
-                        }
-                    }
+                    AddLayer(layerDatum);
                 }
 
                 _layerMapShared = true;
@@ -336,11 +247,13 @@ namespace Robust.Client.GameObjects
 
         void ISerializationHooks.AfterDeserialization()
         {
+            IoCManager.InjectDependencies(this);
+
             {
                 if (!string.IsNullOrWhiteSpace(rsi))
                 {
                     var rsiPath = TextureRoot / rsi;
-                    if(IoCManager.Resolve<IResourceCache>().TryGetResource(rsiPath, out RSIResource? resource))
+                    if(resourceCache.TryGetResource(rsiPath, out RSIResource? resource))
                     {
                         BaseRSI = resource.RSI;
                     }
@@ -373,6 +286,8 @@ namespace Robust.Client.GameObjects
                 LayerMap.Clear();
                 LayerDatums = layerDatums;
             }
+
+            UpdateLocalMatrix();
         }
 
         /// <summary>
@@ -390,6 +305,7 @@ namespace Robust.Client.GameObjects
             offset = other.offset;
             rotation = other.rotation;
             scale = other.scale;
+            UpdateLocalMatrix();
             drawDepth = other.drawDepth;
             _screenLock = other._screenLock;
             _overrideDirection = other._overrideDirection;
@@ -415,9 +331,14 @@ namespace Robust.Client.GameObjects
             RenderOrder = other.RenderOrder;
         }
 
+        internal void UpdateLocalMatrix()
+        {
+            LocalMatrix = Matrix3.CreateTransform(in offset, in rotation, in scale);
+        }
+
         public Matrix3 GetLocalMatrix()
         {
-            return Matrix3.CreateTransform(in offset, in rotation, in scale);
+            return LocalMatrix;
         }
 
         /// <inheritdoc />
@@ -462,14 +383,17 @@ namespace Robust.Client.GameObjects
             _layerMapShared = false;
         }
 
-        public void LayerMapReserveBlank(object key)
+        public int LayerMapReserveBlank(object key)
         {
-            if (LayerMapTryGet(key, out var _))
+            if (LayerMapTryGet(key, out var index))
             {
-                return;
+                return index;
             }
 
-            LayerMapSet(key, AddBlankLayer());
+            index = AddBlankLayer();
+            LayerMapSet(key, index);
+
+            return index;
         }
 
         public int AddBlankLayer(int? newIndex = null)
@@ -478,6 +402,19 @@ namespace Robust.Client.GameObjects
             return AddLayer(layer, newIndex);
         }
 
+        /// <summary>
+        ///     Add a new layer based on some <see cref="PrototypeLayerData"/>.
+        /// </summary>
+        public int AddLayer(PrototypeLayerData layerDatum, int? newIndex = null)
+        {
+            var layer = new Layer(this);
+
+            var index = AddLayer(layer, newIndex);
+
+            LayerSetData(index, layerDatum);
+            return index;
+        }
+
         public int AddLayer(string texturePath, int? newIndex = null)
         {
             return AddLayer(new ResourcePath(texturePath), newIndex);
@@ -653,7 +590,144 @@ namespace Robust.Client.GameObjects
             RemoveLayer(layer);
         }
 
-        public void LayerSetShader(int layer, ShaderInstance? shader)
+        /// <summary>
+        ///     Fills in a layer's values using some <see cref="PrototypeLayerData"/>.
+        /// </summary>
+        public void LayerSetData(int index, PrototypeLayerData layerDatum)
+        {
+            if (Layers.Count <= index)
+            {
+                Logger.ErrorS(LogCategory, "Layer with index '{0}' does not exist, cannot set layer data! Trace:\n{1}",
+                    index, Environment.StackTrace);
+                return;
+            }
+
+            var layer = Layers[index];
+
+            var anyTextureAttempted = false;
+
+            if (!string.IsNullOrWhiteSpace(layerDatum.RsiPath))
+            {
+                var path = TextureRoot / layerDatum.RsiPath;
+
+                if (resourceCache.TryGetResource(path, out RSIResource? resource))
+                {
+                    layer.RSI = resource.RSI;
+                }
+                else
+                {
+                    Logger.ErrorS(LogCategory, "Unable to load layer RSI '{0}'.", path);
+                }
+            }
+
+            if (!string.IsNullOrWhiteSpace(layerDatum.State))
+            {
+                anyTextureAttempted = true;
+                var theRsi = layer.RSI ?? BaseRSI;
+                if (theRsi == null)
+                {
+                    Logger.ErrorS(LogCategory,
+                        "Layer has no RSI to load states from. Cannot use 'state' property. ({0})",
+                        layerDatum.State);
+                }
+                else
+                {
+                    var stateid = new RSI.StateId(layerDatum.State);
+                    layer.State = stateid;
+                    if (theRsi.TryGetState(stateid, out var state))
+                    {
+                        // Always use south because this layer will be cached in the serializer.
+                        layer.AnimationTimeLeft = state.GetDelay(0);
+                    }
+                    else
+                    {
+                        Logger.ErrorS(LogCategory,
+                            $"State '{stateid}' not found in RSI: '{theRsi.Path}'.",
+                            stateid);
+                    }
+                }
+            }
+
+            if (!string.IsNullOrWhiteSpace(layerDatum.TexturePath))
+            {
+                anyTextureAttempted = true;
+                if (layer.State.IsValid)
+                {
+                    Logger.ErrorS(LogCategory,
+                        "Cannot specify 'texture' on a layer if it has an RSI state specified."
+                    );
+                }
+                else
+                {
+                    layer.Texture =
+                        resourceCache.GetResource<TextureResource>(TextureRoot / layerDatum.TexturePath);
+                }
+            }
+
+            if (!string.IsNullOrWhiteSpace(layerDatum.Shader))
+            {
+                if (prototypes.TryIndex<ShaderPrototype>(layerDatum.Shader, out var prototype))
+                {
+                    layer.ShaderPrototype = layerDatum.Shader;
+                    layer.Shader = prototype.Instance();
+                }
+                else
+                {
+                    Logger.ErrorS(LogCategory,
+                        "Shader prototype '{0}' does not exist.",
+                        layerDatum.Shader);
+                }
+            }
+
+            if (layerDatum.MapKeys != null)
+            {
+                foreach (var keyString in layerDatum.MapKeys)
+                {
+                    object key;
+                    if (reflection.TryParseEnumReference(keyString, out var @enum))
+                    {
+                        key = @enum;
+                    }
+                    else
+                    {
+                        key = keyString;
+                    }
+
+                    if (LayerMap.TryGetValue(key, out var mappedIndex))
+                    {
+                        if (mappedIndex != index)
+                            Logger.ErrorS(LogCategory, "Duplicate layer map key definition: {0}", key);
+                        continue;
+                    }
+
+                    _layerMapEnsurePrivate();
+                    LayerMap[key] = index;
+                }
+            }
+
+            layer.Color = layerDatum.Color;
+            layer._rotation = layerDatum.Rotation;
+            layer._offset = layerDatum.Offset;
+            layer._scale = layerDatum.Scale;
+            layer.UpdateLocalMatrix();
+
+            // If neither state: nor texture: were provided we assume that they want a blank invisible layer.
+            layer.Visible = anyTextureAttempted && layerDatum.Visible;
+        }
+
+        public void LayerSetData(object layerKey, PrototypeLayerData data)
+        {
+            if (!LayerMapTryGet(layerKey, out var layer))
+            {
+                Logger.ErrorS(LogCategory, "Layer with key '{0}' does not exist, cannot set shader! Trace:\n{1}",
+                    layerKey, Environment.StackTrace);
+                return;
+            }
+
+            LayerSetData(layer, data);
+        }
+
+        public void LayerSetShader(int layer, ShaderInstance? shader, string? prototype = null)
         {
             if (Layers.Count <= layer)
             {
@@ -664,9 +738,10 @@ namespace Robust.Client.GameObjects
 
             var theLayer = Layers[layer];
             theLayer.Shader = shader;
+            theLayer.ShaderPrototype = prototype;
         }
 
-        public void LayerSetShader(object layerKey, ShaderInstance shader)
+        public void LayerSetShader(object layerKey, ShaderInstance shader, string? prototype = null)
         {
             if (!LayerMapTryGet(layerKey, out var layer))
             {
@@ -675,7 +750,7 @@ namespace Robust.Client.GameObjects
                 return;
             }
 
-            LayerSetShader(layer, shader);
+            LayerSetShader(layer, shader, prototype);
         }
 
         public void LayerSetShader(int layer, string shaderName)
@@ -684,10 +759,12 @@ namespace Robust.Client.GameObjects
             {
                 Logger.ErrorS(LogCategory, "Shader prototype '{0}' does not exist. Trace:\n{1}", shaderName,
                     Environment.StackTrace);
+
+                LayerSetShader(layer, null, null);
+                return;
             }
 
-            // This will set the shader to null if it does not exist.
-            LayerSetShader(layer, prototype?.Instance());
+            LayerSetShader(layer, prototype.Instance(), shaderName);
         }
 
         public void LayerSetShader(object layerKey, string shaderName)
@@ -1148,7 +1225,7 @@ namespace Robust.Client.GameObjects
                 return;
             }
 
-            Layers[layer].SetOffset(layerOffset);
+            Layers[layer].Offset = layerOffset;
         }
 
         public void LayerSetOffset(object layerKey, Vector2 layerOffset)
@@ -1230,25 +1307,6 @@ namespace Robust.Client.GameObjects
             RenderInternal(drawingHandle, eyeRotation, worldRotation, worldPosition, overrideDir);
         }
 
-        private void CalcModelMatrix(int numDirs, Angle eyeRotation, Angle worldRotation, Vector2 worldPosition, out Matrix3 modelMatrix)
-        {
-            Angle angle;
-
-            if (_screenLock)
-            {
-                // Negate the eye rotation in the model matrix, so that later when the view matrix is applied the
-                // sprite will be locked upright to the screen
-                angle = new Angle(-eyeRotation.Theta);
-            }
-            else
-            {
-                angle = CalcRectWorldAngle(worldRotation + eyeRotation, numDirs) - eyeRotation;
-            }
-
-            var sWorldRotation = angle;
-            modelMatrix = Matrix3.CreateTransform(in worldPosition, in sWorldRotation);
-        }
-
         private void RenderInternal(DrawingHandleWorld drawingHandle, Angle eyeRotation, Angle worldRotation, Vector2 worldPosition, Direction? overrideDirection)
         {
             // Reduce the angles to fix math shenanigans
@@ -1257,56 +1315,16 @@ namespace Robust.Client.GameObjects
             if (worldRotation.Theta < 0)
                 worldRotation = new Angle(worldRotation.Theta + Math.Tau);
 
-            // sprite matrix, WITHOUT offset.
-            // offset is applied after sprite numDirs snapping/rotation correction
-            // --> apply at same time as layer offset
-            var spriteMatrix = Matrix3.CreateTransform(Vector2.Zero, rotation, scale);
+            // worldRotation + eyeRotation should be the angle of the entity on-screen. If no-rot is enabled this is just set to zero.
+            // However, at some point later the eye-matrix is applied separately, so we subtract -eye rotation for now:
+            var entityMatrix = Matrix3.CreateTransform(worldPosition, NoRotation ? -eyeRotation : worldRotation);
 
+            Matrix3.Multiply(ref LocalMatrix, ref entityMatrix, out var transform);
+
+            var angle = worldRotation + eyeRotation; // angle on-screen. Used to decide the direction of 4/8 directional RSIs
             foreach (var layer in Layers)
             {
-                if (!layer.Visible)
-                {
-                    continue;
-                }
-
-                var numDirs = GetLayerDirectionCount(layer);
-                var layerRotation = worldRotation + layer.Rotation;
-                var layerPosition = worldPosition + layerRotation.RotateVec(layer._offset + offset);
-
-                CalcModelMatrix(numDirs, eyeRotation, layerRotation, layerPosition, out var modelMatrix);
-                Matrix3.Multiply(ref spriteMatrix, ref modelMatrix, out var transformMatrix);
-                drawingHandle.SetTransform(in transformMatrix);
-
-                RenderLayer(drawingHandle, layer, eyeRotation, layerRotation, overrideDirection);
-            }
-        }
-
-        private void RenderLayer(DrawingHandleWorld drawingHandle, Layer layer, Angle eyeRotation, Angle worldRotation, Direction? overrideDirection)
-        {
-            var texture = GetRenderTexture(layer, worldRotation + eyeRotation, overrideDirection);
-
-            if (layer.Shader != null)
-            {
-                drawingHandle.UseShader(layer.Shader);
-            }
-
-            var layerColor = color * layer.Color;
-
-            var position = -(Vector2)texture.Size / (2f * EyeManager.PixelsPerMeter);
-            var textureSize = texture.Size / (float)EyeManager.PixelsPerMeter;
-            var quad = Box2.FromDimensions(position, textureSize);
-
-            // TODO: Implement layer-specific rotation and scale.
-            // Apply these directly to the box.
-            // Oh and when you do update Layer.LocalToLayer so content doesn't break.
-
-            // handle.Modulate changes the color
-            // drawingHandle.SetTransform() is set above, turning the quad into local space vertices
-            drawingHandle.DrawTextureRectRegion(texture, quad, layerColor);
-
-            if (layer.Shader != null)
-            {
-                drawingHandle.UseShader(null);
+                layer.Render(drawingHandle, ref transform, angle, overrideDirection);
             }
         }
 
@@ -1342,27 +1360,6 @@ namespace Robust.Client.GameObjects
             };
         }
 
-        private Texture GetRenderTexture(Layer layer, Angle worldRotation, Direction? overrideDirection)
-        {
-            var texture = layer.Texture;
-
-            if (layer.State.IsValid)
-            {
-                // Pull texture from RSI state instead.
-                var rsi = layer.RSI ?? BaseRSI;
-                if (rsi == null || !rsi.TryGetState(layer.State, out var state))
-                {
-                    state = GetFallbackState(resourceCache);
-                }
-
-                var layerSpecificDir = layer.EffectiveDirection(state, worldRotation, overrideDirection);
-                texture = state.GetFrame(layerSpecificDir, layer.AnimationFrame);
-            }
-
-            texture ??= resourceCache.GetFallback<TextureResource>().Texture;
-            return texture;
-        }
-
         public void FrameUpdate(float delta)
         {
             foreach (var t in Layers)
@@ -1417,12 +1414,14 @@ namespace Robust.Client.GameObjects
 
             Visible = thestate.Visible;
             DrawDepth = thestate.DrawDepth;
-            Scale = thestate.Scale;
-            Rotation = thestate.Rotation;
-            Offset = thestate.Offset;
+            scale = thestate.Scale;
+            rotation = thestate.Rotation;
+            offset = thestate.Offset;
+            UpdateLocalMatrix();
             Color = thestate.Color;
             RenderOrder = thestate.RenderOrder;
 
+
             if (thestate.BaseRsiPath != null && BaseRSI != null)
             {
                 if (resourceCache.TryGetResource<RSIResource>(TextureRoot / thestate.BaseRsiPath, out var res))
@@ -1438,43 +1437,8 @@ namespace Robust.Client.GameObjects
                 }
             }
 
-            // Maybe optimize this to NOT full clear.
-            Layers.Clear();
-            for (var i = 0; i < thestate.Layers.Count; i++)
-            {
-                var netlayer = thestate.Layers[i];
-                var layer = new Layer(this)
-                {
-                    // These are easy so do them here.
-                    Scale = netlayer.Scale,
-                    Rotation = netlayer.Rotation,
-                    Visible = netlayer.Visible,
-                    Color = netlayer.Color
-                };
-                Layers.Add(layer);
-
-                // Using the public API to handle errors.
-                // Probably slow as crap.
-                // Who am I kidding, DEFINITELY.
-                if (netlayer.Shader != null)
-                {
-                    LayerSetShader(i, netlayer.Shader);
-                }
-
-                if (netlayer.RsiPath != null)
-                {
-                    LayerSetRSI(i, netlayer.RsiPath);
-                }
-
-                if (netlayer.TexturePath != null)
-                {
-                    LayerSetTexture(i, netlayer.TexturePath);
-                }
-                else if (netlayer.State != null)
-                {
-                    LayerSetState(i, netlayer.State);
-                }
-            }
+            // Maybe optimize this to NOT fully clear the layers. (see LayerDatums setter function)
+            LayerDatums = thestate.Layers;
         }
 
         private void QueueUpdateIsInert()
@@ -1553,35 +1517,61 @@ namespace Robust.Client.GameObjects
         }
 
         /// <inheritdoc/>
-        public Box2 CalculateBoundingBox(Vector2 worldPos)
+        public Box2Rotated CalculateRotatedBoundingBox(Vector2 worldPosition, Angle worldRotation, IEye? eye = null)
         {
             // fast check for empty sprites
-            if (Layers.Count == 0)
-                return new Box2(worldPos, worldPos);
+            if (!Visible || Layers.Count == 0)
+            {
+                return new Box2Rotated(new Box2(worldPosition, worldPosition), Angle.Zero, worldPosition);
+            }
+
+            // We need to modify world rotation so that it lies between 0 and 2pi.
+            // This matters for 4 or 8 directional sprites deciding which quadrant (octant?) they lie in.
+            // the 0->2pi convention is set by the sprite-rendering code that selects the layers.
+            // See RenderInternal().
+
+            worldRotation = worldRotation.Reduced();
+            if (worldRotation.Theta < 0)
+                worldRotation = new Angle(worldRotation.Theta + Math.Tau);
+
+            eye ??= eyeManager.CurrentEye;
+
+            // Need relative angle on screen for determining the sprite rsi direction.
+            Angle relativeRotation = NoRotation
+                ? Angle.Zero
+                : worldRotation + eye.Rotation;
 
             // we need to calculate bounding box taking into account all nested layers
-            // because layers can have offsets, scale or rotation we need to calculate a new BB
-            // based on lowest bottomLeft and hightest topRight points from all layers
-            var box = Layers[0].CalculateBoundingBox();
+            // because layers can have offsets, scale or rotation, we need to calculate a new BB
+            // based on lowest bottomLeft and highest topRight points from all layers
+            var box = Layers[0].CalculateBoundingBox(relativeRotation);
 
             for (int i = 1; i < Layers.Count; i++)
             {
                 var layer = Layers[i];
-                var layerBB = layer.CalculateBoundingBox();
+                if (!layer.Visible) continue;
+                var layerBB = layer.CalculateBoundingBox(relativeRotation);
 
                 box = box.Union(layerBB);
             }
 
-            // apply sprite transformations and calculate sprite bounding box
-            // we can optimize it a bit, if sprite doesn't have rotation
-            var spriteBox = box.Scale(Scale);
-            var spriteHasRotation = !Rotation.EqualsApprox(Angle.Zero);
-            var spriteBB = spriteHasRotation ?
-                new Box2Rotated(spriteBox, Rotation).CalcBoundingBox() : spriteBox;
+            // Next, what we do is take the box2 and apply the sprite's transform, and then the entity's transform. We
+            // could do this via Matrix3.TransformBox, but that only yields bounding boxes. So instead we manually
+            // transform our box by the combination of these matrices:
 
-            // move it all to world transform system (with sprite offset)
-            var worldBB = spriteBB.Translated(Offset + worldPos);
-            return worldBB;
+            if (Scale != Vector2.One)
+                box = box.Scale(Scale);
+
+            var adjustedOffset = NoRotation
+                ? (-eye.Rotation).RotateVec(Offset)
+                : worldRotation.RotateVec(Offset);
+
+            Vector2 position = adjustedOffset + worldPosition;
+            Angle finalRotation = NoRotation
+                ? Rotation - eye.Rotation
+                : Rotation + worldRotation;
+
+            return new Box2Rotated(box.Translated(position), finalRotation, position);
         }
 
         internal void UpdateBounds()
@@ -1615,10 +1605,11 @@ namespace Robust.Client.GameObjects
             Flip = 3,
         }
 
-        public sealed class Layer : ISpriteLayer
+        public sealed class Layer : ISpriteLayer, ISerializationHooks
         {
             [ViewVariables] private readonly SpriteComponent _parent;
 
+            [ViewVariables] public string? ShaderPrototype;
             [ViewVariables] public ShaderInstance? Shader;
             [ViewVariables] public Texture? Texture;
 
@@ -1628,11 +1619,37 @@ namespace Robust.Client.GameObjects
             [ViewVariables] public float AnimationTime;
             [ViewVariables] public int AnimationFrame;
 
-            [ViewVariables(VVAccess.ReadWrite)]
-            public Vector2 Scale { get; set; } = Vector2.One;
+            public Matrix3 LocalMatrix = Matrix3.Identity;
 
             [ViewVariables(VVAccess.ReadWrite)]
-            public Angle Rotation { get; set; }
+            public Vector2 Scale
+            {
+                get => _scale;
+                set
+                {
+                    if (_scale.EqualsApprox(value)) return;
+
+                    _scale = value;
+                    UpdateLocalMatrix();
+                    _parent.UpdateBounds();
+                }
+            }
+            internal Vector2 _scale = Vector2.One;
+
+            [ViewVariables(VVAccess.ReadWrite)]
+            public Angle Rotation
+            {
+                get => _rotation;
+                set
+                {
+                    if (_rotation.EqualsApprox(value)) return;
+
+                    _rotation = value;
+                    UpdateLocalMatrix();
+                    _parent.UpdateBounds();
+                }
+            }
+            internal Angle _rotation = Angle.Zero;
 
             [ViewVariables(VVAccess.ReadWrite)]
             public bool Visible = true;
@@ -1652,6 +1669,7 @@ namespace Robust.Client.GameObjects
                     if (_offset.EqualsApprox(value)) return;
 
                     _offset = value;
+                    UpdateLocalMatrix();
                     _parent.UpdateBounds();
                 }
             }
@@ -1675,6 +1693,7 @@ namespace Robust.Client.GameObjects
                 if (toClone.Shader != null)
                 {
                     Shader = toClone.Shader.Mutable ? toClone.Shader.Duplicate() : toClone.Shader;
+                    ShaderPrototype = toClone.ShaderPrototype;
                 }
                 Texture = toClone.Texture;
                 RSI = toClone.RSI;
@@ -1682,14 +1701,26 @@ namespace Robust.Client.GameObjects
                 AnimationTimeLeft = toClone.AnimationTimeLeft;
                 AnimationTime = toClone.AnimationTime;
                 AnimationFrame = toClone.AnimationFrame;
-                Scale = toClone.Scale;
-                Rotation = toClone.Rotation;
+                _scale = toClone.Scale;
+                _rotation = toClone.Rotation;
+                _offset = toClone.Offset;
+                UpdateLocalMatrix();
                 Visible = toClone.Visible;
                 Color = toClone.Color;
                 DirOffset = toClone.DirOffset;
                 AutoAnimated = toClone.AutoAnimated;
             }
 
+            void ISerializationHooks.AfterDeserialization()
+            {
+                UpdateLocalMatrix();
+            }
+
+            internal void UpdateLocalMatrix()
+            {
+                LocalMatrix = Matrix3.CreateTransform(in _offset, in _rotation, in _scale);
+            }
+
             RSI? ISpriteLayer.Rsi { get => RSI; set => SetRsi(value); }
             RSI.StateId ISpriteLayer.RsiState { get => State; set => SetState(value); }
             Texture? ISpriteLayer.Texture { get => Texture; set => SetTexture(value); }
@@ -1701,7 +1732,7 @@ namespace Robust.Client.GameObjects
                     Color = Color,
                     Rotation = Rotation,
                     Scale = Scale,
-                    //todo Shader = Shader,
+                    Shader = ShaderPrototype,
                     State = State.Name,
                     Visible = Visible,
                     RsiPath = RSI?.Path?.ToString(),
@@ -1730,7 +1761,7 @@ namespace Robust.Client.GameObjects
                 set => SetAutoAnimated(value);
             }
 
-            public RSI.State.Direction EffectiveDirection(Angle worldRotation)
+            public RSIDirection EffectiveDirection(Angle worldRotation)
             {
                 if (State == default)
                 {
@@ -1751,22 +1782,16 @@ namespace Robust.Client.GameObjects
                 return default;
             }
 
-            public Vector2 LocalToLayer(Vector2 localPos)
-            {
-                // TODO: scale & rotation for layers is currently unimplemented.
-                return localPos;
-            }
-
-            public RSI.State.Direction EffectiveDirection(RSI.State state, Angle worldRotation,
+            public RSIDirection EffectiveDirection(RSI.State state, Angle worldRotation,
                 Direction? overrideDirection)
             {
                 if (state.Directions == RSI.State.DirectionType.Dir1)
                 {
-                    return RSI.State.Direction.South;
+                    return RSIDirection.South;
                 }
                 else
                 {
-                    RSI.State.Direction dir;
+                    RSIDirection dir;
                     if (overrideDirection != null)
                     {
                         dir = overrideDirection.Value.Convert(state.Directions);
@@ -1849,7 +1874,7 @@ namespace Robust.Client.GameObjects
                     }
                     else
                     {
-                        Logger.ErrorS(LogCategory, "State '{0}' does not exist in set RSI. Trace:\n{1}", State,
+                        Logger.ErrorS(LogCategory, "State '{0}' does not exist in set RSI ({1}). Trace:\n{2}", State, rsi?.Path?.ToString() ?? "null",
                             Environment.StackTrace);
                         Texture = null;
                     }
@@ -1898,11 +1923,6 @@ namespace Robust.Client.GameObjects
                 _parent.QueueUpdateIsInert();
             }
 
-            public void SetOffset(Vector2 offset)
-            {
-                Offset = offset;
-            }
-
             /// <inheritdoc/>
             public Vector2i PixelSize
             {
@@ -1923,10 +1943,121 @@ namespace Robust.Client.GameObjects
             }
 
             /// <inheritdoc/>
-            public Box2 CalculateBoundingBox()
+            public Box2 CalculateBoundingBox(Angle angle)
             {
-                // TODO: scale & rotation for layers is currently unimplemented.
-                return Box2.CenteredAround(Offset, PixelSize / EyeManager.PixelsPerMeter);
+                // Other than some special cases for simple layers, this will basically just apply the matrix obtained
+                // via GetLayerDrawMatrix() to this layer's bounding box.
+
+                var rsiState = GetActualState();
+
+                var dir = (rsiState == null || rsiState.Directions == RSI.State.DirectionType.Dir1)
+                    ? RSIDirection.South
+                    : angle.ToRsiDirection(rsiState.Directions);
+
+                // special case for simple layers. The vast majority of layers are like this.
+                if (_rotation == Angle.Zero)
+                {
+                    var textureSize = PixelSize / EyeManager.PixelsPerMeter;
+
+                    // this switch block is basically an explicit version of the `rsiDirectionMatrix` in `GetLayerDrawMatrix()`.
+                    var box = dir switch
+                    {
+                        // No rotation:
+                        RSIDirection.South or RSIDirection.North => Box2.CenteredAround(Offset, textureSize),
+                        // rotate 90 degrees:
+                        RSIDirection.East or RSIDirection.West => Box2.CenteredAround(Offset, (textureSize.Y, textureSize.X)),
+                        // rotated 45 degrees (any 45 degree rotated rectangle has a square bounding box with sides of length (x+y)/sqrt(2) )
+                        _ => Box2.CenteredAround(Offset, Vector2.One * (textureSize.X + textureSize.Y) / MathF.Sqrt(2))
+                    };
+
+                    return _scale == Vector2.One ? box : box.Scale(_scale);
+                }
+
+                // Welp we have some non-zero _rotation, so lets just apply the generalized layer transform and get the bounding box from where;
+                GetLayerDrawMatrix(dir, out var layerDrawMatrix);
+                return layerDrawMatrix.TransformBox(Box2.CentredAroundZero(PixelSize / EyeManager.PixelsPerMeter));
+            }
+
+            internal RSI.State? GetActualState()
+            {
+                if (!State.IsValid)
+                    return null;
+
+                // Pull texture from RSI state
+                var rsi = RSI ?? _parent.BaseRSI;
+                if (rsi == null || !rsi.TryGetState(State, out var rsiState))
+                {
+                    rsiState = GetFallbackState(_parent.resourceCache);
+                }
+
+                return rsiState;
+            }
+
+            /// <summary>
+            ///     Given the apparent rotation of an entity on screen (world + eye rotation), get layer's matrix for drawing &
+            ///     relevant RSI direction.
+            /// </summary>
+            public void GetLayerDrawMatrix(RSIDirection dir, out Matrix3 layerDrawMatrix)
+            {
+                if (_parent.NoRotation)
+                    layerDrawMatrix = LocalMatrix;
+                else
+                {
+                    var rsiDirectionMatrix = Matrix3.CreateTransform(Vector2.Zero, -dir.Convert().ToAngle());
+                    Matrix3.Multiply(ref rsiDirectionMatrix, ref LocalMatrix, out layerDrawMatrix);
+                }
+            }
+
+            internal void Render(DrawingHandleWorld drawingHandle, ref Matrix3 spriteMatrix, Angle angle, Direction? overrideDirection)
+            {
+                if (!Visible)
+                    return;
+
+                var rsiState = GetActualState();
+
+                var dir = (rsiState == null || rsiState.Directions == RSI.State.DirectionType.Dir1)
+                    ? RSIDirection.South
+                    : angle.ToRsiDirection(rsiState.Directions);
+
+                // Set the drawing transform for this  layer
+                GetLayerDrawMatrix(dir, out var layerMatrix);
+                Matrix3.Multiply(ref layerMatrix, ref spriteMatrix, out var transformMatrix);
+                drawingHandle.SetTransform(in transformMatrix);
+
+                // The direction used to draw the sprite can differ from the one that the angle would naively suggest,
+                // due to direction overrides or offsets.
+                if (overrideDirection != null && rsiState != null)
+                    dir = overrideDirection.Value.Convert(rsiState.Directions);
+                dir = dir.OffsetRsiDir(DirOffset);
+
+                // Get the correct directional texture from the state, and draw it!
+                var texture = GetRenderTexture(rsiState, dir);
+                RenderTexture(drawingHandle, texture);
+            }
+
+            private void RenderTexture(DrawingHandleWorld drawingHandle, Texture texture)
+            {
+                if (Shader != null)
+                    drawingHandle.UseShader(Shader);
+
+                var layerColor = _parent.color * Color;
+
+                var position = -(Vector2)texture.Size / (2f * EyeManager.PixelsPerMeter);
+                var textureSize = texture.Size / (float)EyeManager.PixelsPerMeter;
+                var quad = Box2.FromDimensions(position, textureSize);
+
+                drawingHandle.DrawTextureRectRegion(texture, quad, layerColor);
+
+                if (Shader != null)
+                    drawingHandle.UseShader(null);
+            }
+
+            private Texture GetRenderTexture(RSI.State? state, RSIDirection dir)
+            {
+                if (state == null)
+                    return Texture ?? _parent.resourceCache.GetFallback<TextureResource>().Texture;
+
+                return state.GetFrame(dir, AnimationFrame);
             }
         }
 
@@ -2034,6 +2165,7 @@ namespace Robust.Client.GameObjects
             return results;
         }
 
+        [Obsolete("Use SpriteSystem")]
         public static IRsiStateLike GetPrototypeIcon(EntityPrototype prototype, IResourceCache resourceCache)
         {
             var icon = IconComponent.GetPrototypeIcon(prototype, resourceCache);

Robust.Client/GameObjects/EntitySystems/AppearanceSystem.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using JetBrains.Annotations;
 using Robust.Shared.GameObjects;
@@ -6,7 +7,7 @@ using Robust.Shared.GameStates;
 namespace Robust.Client.GameObjects
 {
     [UsedImplicitly]
-    internal sealed class AppearanceSystem : SharedAppearanceSystem
+    public sealed class AppearanceSystem : SharedAppearanceSystem
     {
         private readonly Queue<ClientAppearanceComponent> _queuedUpdates = new();
 
@@ -50,10 +51,33 @@ namespace Robust.Client.GameObjects
 
             if (!stateDiff) return;
 
-            component.AppearanceData = actualState.Data;
+            component.AppearanceData = CloneAppearanceData(actualState.Data);
             MarkDirty(component);
         }
 
+        /// <summary>
+        ///     Take in an appearance data dictionary and attempt to clone it.
+        /// </summary>
+        /// <remarks>
+        ///     As some appearance data values are not simple value-type objects, this is not just a shallow clone.
+        /// </remarks>
+        private Dictionary<object, object> CloneAppearanceData(Dictionary<object, object> data)
+        {
+            Dictionary<object, object> newDict = new(data.Count);
+
+            foreach (var (key, value) in data)
+            {
+                if (value.GetType().IsValueType)
+                    newDict[key] = value;
+                else if (value is ICloneable cloneable)
+                    newDict[key] = cloneable.Clone();
+                else
+                    throw new NotSupportedException("Invalid object in appearance data dictionary. Appearance data must be cloneable");
+            }
+
+            return newDict;
+        }
+
         public override void MarkDirty(AppearanceComponent component)
         {
             if (component.AppearanceDirty)
@@ -107,7 +131,7 @@ namespace Robust.Client.GameObjects
     [ByRefEvent]
     public struct AppearanceChangeEvent
     {
-        public AppearanceComponent Component = default!;
-        public IReadOnlyDictionary<object, object> AppearanceData = default!;
+        public AppearanceComponent Component;
+        public IReadOnlyDictionary<object, object> AppearanceData;
     }
 }

Robust.Client/GameObjects/EntitySystems/ContainerSystem.cs

@@ -168,7 +168,7 @@ namespace Robust.Client.GameObjects
                 // This container is expecting an entity... but it got parented to some other entity???
                 // Ah well, the sever should send a new container state that updates expected entities so just ignore it for now.
                 return;
-            }    
+            }
 
             RemoveExpectedEntity(message.Entity);
 
@@ -210,68 +210,101 @@ namespace Robust.Client.GameObjects
         public override void FrameUpdate(float frameTime)
         {
             base.FrameUpdate(frameTime);
+            var pointQuery = EntityManager.GetEntityQuery<PointLightComponent>();
+            var spriteQuery = EntityManager.GetEntityQuery<SpriteComponent>();
+            var xformQuery = EntityManager.GetEntityQuery<TransformComponent>();
 
             foreach (var toUpdate in _updateQueue)
             {
-                if (EntityManager.Deleted(toUpdate))
-                {
+                if (Deleted(toUpdate))
                     continue;
-                }
 
-                UpdateEntityRecursively(toUpdate);
+                UpdateEntityRecursively(toUpdate, xformQuery, pointQuery, spriteQuery);
             }
 
             _updateQueue.Clear();
         }
 
-        private void UpdateEntityRecursively(EntityUid entity)
+        private void UpdateEntityRecursively(
+            EntityUid entity,
+            EntityQuery<TransformComponent> xformQuery,
+            EntityQuery<PointLightComponent> pointQuery,
+            EntityQuery<SpriteComponent> spriteQuery)
         {
-            // TODO: Since we are recursing down,
-            // we could cache ShowContents data here to speed it up for children.
-            // Am lazy though.
-            UpdateEntity(entity);
+            // Recursively go up parents and containers to see whether both sprites and lights need to be occluded
+            // Could maybe optimise this more by checking nearest parent that has sprite / light and whether it's container
+            // occluded but this probably isn't a big perf issue.
+            var xform = xformQuery.GetComponent(entity);
+            var parent = xform.ParentUid;
+            var child = entity;
+            var spriteOccluded = false;
+            var lightOccluded = false;
 
-            foreach (var child in EntityManager.GetComponent<TransformComponent>(entity).Children)
+            while (parent.IsValid() && !spriteOccluded && !lightOccluded)
             {
-                UpdateEntityRecursively(child.Owner);
+                var parentXform = xformQuery.GetComponent(parent);
+                if (TryComp<ContainerManagerComponent>(parent, out var manager) && manager.TryGetContainer(child, out var container))
+                {
+                    spriteOccluded = spriteOccluded || !container.ShowContents;
+                    lightOccluded = lightOccluded || container.OccludesLight;
+                }
+
+                child = parent;
+                parent = parentXform.ParentUid;
             }
+
+            // Alright so
+            // This is the CBT bit.
+            // The issue is we need to go through the children and re-check whether they are or are not contained.
+            // if they are contained then the occlusion values may need updating for all those children
+            UpdateEntity(entity, xform, xformQuery, pointQuery, spriteQuery, spriteOccluded, lightOccluded);
         }
 
-        private void UpdateEntity(EntityUid entity)
+        private void UpdateEntity(
+            EntityUid entity,
+            TransformComponent xform,
+            EntityQuery<TransformComponent> xformQuery,
+            EntityQuery<PointLightComponent> pointQuery,
+            EntityQuery<SpriteComponent> spriteQuery,
+            bool spriteOccluded,
+            bool lightOccluded)
         {
-            if (EntityManager.TryGetComponent(entity, out SpriteComponent? sprite))
+            if (spriteQuery.TryGetComponent(entity, out var sprite))
             {
-                sprite.ContainerOccluded = false;
-
-                // We have to recursively scan for containers upwards in case of nested containers.
-                var tempParent = entity;
-                while (tempParent.TryGetContainer(out var container))
-                {
-                    if (!container.ShowContents)
-                    {
-                        sprite.ContainerOccluded = true;
-                        break;
-                    }
-
-                    tempParent = container.Owner;
-                }
+                sprite.ContainerOccluded = spriteOccluded;
             }
 
-            if (EntityManager.TryGetComponent(entity, out PointLightComponent? light))
+            if (pointQuery.TryGetComponent(entity, out var light))
             {
-                light.ContainerOccluded = false;
+                light.ContainerOccluded = lightOccluded;
+            }
 
-                // We have to recursively scan for containers upwards in case of nested containers.
-                var tempParent = entity;
-                while (tempParent.TryGetContainer(out var container))
+            var childEnumerator = xform.ChildEnumerator;
+
+            // Try to avoid TryComp if we already know stuff is occluded.
+            if ((!spriteOccluded || !lightOccluded) && TryComp<ContainerManagerComponent>(entity, out var manager))
+            {
+                while (childEnumerator.MoveNext(out var child))
                 {
-                    if (container.OccludesLight)
+                    // Thank god it's by value and not by ref.
+                    var childSpriteOccluded = spriteOccluded;
+                    var childLightOccluded = lightOccluded;
+
+                    // We already know either sprite or light is not occluding so need to check container.
+                    if (manager.TryGetContainer(child.Value, out var container))
                     {
-                        light.ContainerOccluded = true;
-                        break;
+                        childSpriteOccluded = childSpriteOccluded || !container.ShowContents;
+                        childLightOccluded = childLightOccluded || container.OccludesLight;
                     }
 
-                    tempParent = container.Owner;
+                    UpdateEntity(child.Value, xformQuery.GetComponent(child.Value), xformQuery, pointQuery, spriteQuery, childSpriteOccluded, childLightOccluded);
+                }
+            }
+            else
+            {
+                while (childEnumerator.MoveNext(out var child))
+                {
+                    UpdateEntity(child.Value, xformQuery.GetComponent(child.Value), xformQuery, pointQuery, spriteQuery, spriteOccluded, lightOccluded);
                 }
             }
         }

Robust.Client/GameObjects/EntitySystems/DebugLightTreeSystem.cs

@@ -25,7 +25,7 @@ namespace Robust.Client.GameObjects
                 if (_enabled)
                 {
                     _lightOverlay = new DebugLightOverlay(
-                        IoCManager.Resolve<IEntityLookup>(),
+                        EntitySystem.Get<EntityLookupSystem>(),
                         IoCManager.Resolve<IEyeManager>(),
                         IoCManager.Resolve<IMapManager>(),
                         Get<RenderingTreeSystem>());
@@ -44,7 +44,7 @@ namespace Robust.Client.GameObjects
 
         private sealed class DebugLightOverlay : Overlay
         {
-            private IEntityLookup _lookup;
+            private EntityLookupSystem _lookup;
             private IEyeManager _eyeManager;
             private IMapManager _mapManager;
 
@@ -52,7 +52,7 @@ namespace Robust.Client.GameObjects
 
             public override OverlaySpace Space => OverlaySpace.WorldSpace;
 
-            public DebugLightOverlay(IEntityLookup lookup, IEyeManager eyeManager, IMapManager mapManager, RenderingTreeSystem tree)
+            public DebugLightOverlay(EntityLookupSystem lookup, IEyeManager eyeManager, IMapManager mapManager, RenderingTreeSystem tree)
             {
                 _lookup = lookup;
                 _eyeManager = eyeManager;
@@ -72,7 +72,7 @@ namespace Robust.Client.GameObjects
                 {
                     foreach (var light in tree.LightTree)
                     {
-                        var aabb = _lookup.GetWorldAabbFromEntity(light.Owner);
+                        var aabb = _lookup.GetWorldAABB(light.Owner);
                         if (!aabb.Intersects(worldBounds)) continue;
 
                         args.WorldHandle.DrawRect(aabb, Color.Green.WithAlpha(0.1f));

Robust.Client/GameObjects/EntitySystems/EffectSystem.cs

@@ -323,7 +323,7 @@ namespace Robust.Client.GameObjects
         {
             private readonly IPlayerManager _playerManager;
 
-            public override OverlaySpace Space => OverlaySpace.WorldSpace;
+            public override OverlaySpace Space => OverlaySpace.WorldSpaceBelowFOV;
 
             private readonly ShaderInstance _unshadedShader;
             private readonly EffectSystem _owner;
@@ -377,6 +377,9 @@ namespace Robust.Client.GameObjects
                         (attachedXform?.Coordinates ?? effect.Coordinates)
                         .Offset(effect.AttachedOffset);
 
+                    // If we've never seen the entity before then can't resolve coordinates.
+                    if (!coordinates.IsValid(_entityManager)) continue;
+
                     // ???
                     var rotation = attachedXform?.WorldRotation ?? _entityManager.GetComponent<TransformComponent>(coordinates.EntityId).WorldRotation;
 

Robust.Client/GameObjects/EntitySystems/GridRenderingSystem.cs

@@ -0,0 +1,19 @@
+using Robust.Client.Graphics;
+using Robust.Shared.GameObjects;
+
+namespace Robust.Client.GameObjects;
+
+internal class GridRenderingSystem : EntitySystem
+{
+    private readonly IClydeInternal _clyde;
+
+    public GridRenderingSystem(IClydeInternal clyde)
+    {
+        _clyde = clyde;
+    }
+
+    public override void Initialize()
+    {
+        _clyde.RegisterGridEcsEvents();
+    }
+}

Robust.Client/GameObjects/EntitySystems/InputSystem.cs

@@ -4,11 +4,15 @@ using Robust.Client.Input;
 using Robust.Client.Player;
 using Robust.Shared;
 using Robust.Shared.Configuration;
+using Robust.Shared.Console;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Input;
 using Robust.Shared.IoC;
 using Robust.Shared.Log;
+using Robust.Shared.Map;
+using Robust.Shared.Maths;
 using Robust.Shared.Players;
+using Robust.Shared.Timing;
 using Robust.Shared.Utility;
 
 namespace Robust.Client.GameObjects
@@ -21,6 +25,8 @@ namespace Robust.Client.GameObjects
         [Dependency] private readonly IInputManager _inputManager = default!;
         [Dependency] private readonly IPlayerManager _playerManager = default!;
         [Dependency] private readonly IClientGameStateManager _stateManager = default!;
+        [Dependency] private readonly IConsoleHost _conHost = default!;
+        [Dependency] private readonly IGameTiming _timing = default!;
 
         private readonly IPlayerCommandStates _cmdStates = new PlayerCommandStates();
 
@@ -108,6 +114,43 @@ namespace Robust.Client.GameObjects
         public override void Initialize()
         {
             SubscribeLocalEvent<PlayerAttachSysMessage>(OnAttachedEntityChanged);
+
+            _conHost.RegisterCommand("incmd",
+                "Inserts an input command into the simulation",
+                "incmd <KeyFunction> <d|u KeyState> <wxPos> <wyPos>",
+                GenerateInputCommand);
+        }
+
+        public override void Shutdown()
+        {
+            base.Shutdown();
+
+            _conHost.UnregisterCommand("incmd");
+        }
+
+        private void GenerateInputCommand(IConsoleShell shell, string argstr, string[] args)
+        {
+            var localPlayer = _playerManager.LocalPlayer;
+            if(localPlayer is null)
+                return;
+
+            var pent = localPlayer.ControlledEntity;
+            if(pent is null)
+                return;
+
+            BoundKeyFunction keyFunction = new BoundKeyFunction(args[0]);
+            BoundKeyState state = args[1] == "u" ? BoundKeyState.Up: BoundKeyState.Down;
+
+            var pxform = Transform(pent.Value);
+            var wPos = pxform.WorldPosition + new Vector2(float.Parse(args[2]), float.Parse(args[3]));
+            var coords = EntityCoordinates.FromMap(EntityManager, pent.Value, new MapCoordinates(wPos, pxform.MapID));
+
+            var funcId = _inputManager.NetworkBindMap.KeyFunctionID(keyFunction);
+
+            var message = new FullInputCmdMessage(_timing.CurTick, _timing.TickFraction, funcId, state,
+                coords, new ScreenCoordinates(0, 0, default), EntityUid.Invalid);
+
+            HandleInputCommand(localPlayer.Session, keyFunction, message);
         }
 
         private void OnAttachedEntityChanged(PlayerAttachSysMessage message)

Robust.Client/GameObjects/EntitySystems/RenderingTreeSystem.cs

@@ -70,8 +70,9 @@ namespace Robust.Client.GameObjects
             UpdatesAfter.Add(typeof(TransformSystem));
             UpdatesAfter.Add(typeof(PhysicsSystem));
 
-            _mapManager.MapCreated += MapManagerOnMapCreated;
-            _mapManager.OnGridCreated += MapManagerOnGridCreated;
+            SubscribeLocalEvent<MapChangedEvent>(MapManagerOnMapCreated);
+
+            SubscribeLocalEvent<GridInitializeEvent>(MapManagerOnGridCreated);
 
             // Due to how recursion works, this must be done.
             SubscribeLocalEvent<MoveEvent>(AnythingMoved);
@@ -113,12 +114,18 @@ namespace Robust.Client.GameObjects
 
         private void AnythingMoved(ref MoveEvent args)
         {
-            var xforms = EntityManager.GetEntityQuery<TransformComponent>();
+            var pointQuery = EntityManager.GetEntityQuery<PointLightComponent>();
+            var spriteQuery = EntityManager.GetEntityQuery<SpriteComponent>();
+            var xformQuery = EntityManager.GetEntityQuery<TransformComponent>();
 
-            AnythingMovedSubHandler(args.Sender, xforms);
+            AnythingMovedSubHandler(args.Sender, xformQuery, pointQuery, spriteQuery);
         }
 
-        private void AnythingMovedSubHandler(EntityUid uid, EntityQuery<TransformComponent> xforms)
+        private void AnythingMovedSubHandler(
+            EntityUid uid,
+            EntityQuery<TransformComponent> xformQuery,
+            EntityQuery<PointLightComponent> pointQuery,
+            EntityQuery<SpriteComponent> spriteQuery)
         {
             // To avoid doing redundant updates (and we don't need to update a grid's children ever)
             if (!_checkedChildren.Add(uid) || EntityManager.HasComponent<RenderingTreeComponent>(uid)) return;
@@ -127,17 +134,19 @@ namespace Robust.Client.GameObjects
             // WHATEVER YOU DO, DON'T REPLACE THIS WITH SPAMMING EVENTS UNLESS YOU HAVE A GUARANTEE IT WON'T LAG THE GC.
             // (Struct-based events ok though)
             // Ironically this was lagging the GC lolz
-            if (EntityManager.TryGetComponent(uid, out SpriteComponent? sprite))
+            if (spriteQuery.TryGetComponent(uid, out var sprite))
                 QueueSpriteUpdate(sprite);
 
-            if (EntityManager.TryGetComponent(uid, out PointLightComponent? light))
+            if (pointQuery.TryGetComponent(uid, out var light))
                 QueueLightUpdate(light);
 
-            if (!xforms.TryGetComponent(uid, out var xform)) return;
+            if (!xformQuery.TryGetComponent(uid, out var xform)) return;
 
-            foreach (var child in xform.ChildEntities)
+            var childEnumerator = xform.ChildEnumerator;
+
+            while (childEnumerator.MoveNext(out var child))
             {
-                AnythingMovedSubHandler(child, xforms);
+                AnythingMovedSubHandler(child.Value, xformQuery, pointQuery, spriteQuery);
             }
         }
 
@@ -212,13 +221,6 @@ namespace Robust.Client.GameObjects
         }
         #endregion
 
-        public override void Shutdown()
-        {
-            base.Shutdown();
-            _mapManager.MapCreated -= MapManagerOnMapCreated;
-            _mapManager.OnGridCreated -= MapManagerOnGridCreated;
-        }
-
         private void OnTreeRemove(EntityUid uid, RenderingTreeComponent component, ComponentRemove args)
         {
             foreach (var sprite in component.SpriteTree)
@@ -235,9 +237,9 @@ namespace Robust.Client.GameObjects
             component.LightTree.Clear();
         }
 
-        private void MapManagerOnMapCreated(object? sender, MapEventArgs e)
+        private void MapManagerOnMapCreated(MapChangedEvent e)
         {
-            if (e.Map == MapId.Nullspace)
+            if (e.Destroyed || e.Map == MapId.Nullspace)
             {
                 return;
             }
@@ -245,9 +247,9 @@ namespace Robust.Client.GameObjects
             EntityManager.EnsureComponent<RenderingTreeComponent>(_mapManager.GetMapEntityId(e.Map));
         }
 
-        private void MapManagerOnGridCreated(MapId mapId, GridId gridId)
+        private void MapManagerOnGridCreated(GridInitializeEvent ev)
         {
-            EntityManager.EnsureComponent<RenderingTreeComponent>(_mapManager.GetGrid(gridId).GridEntityId);
+            EntityManager.EnsureComponent<RenderingTreeComponent>(_mapManager.GetGrid(ev.GridId).GridEntityId);
         }
 
         private RenderingTreeComponent? GetRenderTree(EntityUid entity, EntityQuery<TransformComponent> xforms)
@@ -369,13 +371,10 @@ namespace Robust.Client.GameObjects
         private Box2 SpriteAabbFunc(in SpriteComponent value)
         {
             var xforms = EntityManager.GetEntityQuery<TransformComponent>();
-
             var xform = xforms.GetComponent(value.Owner);
             var (worldPos, worldRot) = xform.GetWorldPositionRotation();
-            var bounds = new Box2Rotated(value.CalculateBoundingBox(worldPos), worldRot, worldPos);
-            var tree = GetRenderTree(value.Owner, xforms);
 
-            return tree == null ? bounds.CalcBoundingBox() : xforms.GetComponent(tree.Owner).InvWorldMatrix.TransformBox(bounds);
+            return SpriteAabbFunc(value, worldPos, worldRot, xforms);
         }
 
         private Box2 LightAabbFunc(in PointLightComponent value)
@@ -392,7 +391,7 @@ namespace Robust.Client.GameObjects
 
         private Box2 SpriteAabbFunc(SpriteComponent value, Vector2 worldPos, Angle worldRot, EntityQuery<TransformComponent> xforms)
         {
-            var bounds = new Box2Rotated(value.CalculateBoundingBox(worldPos), worldRot, worldPos);
+            var bounds = value.CalculateRotatedBoundingBox(worldPos, worldRot);
             var tree = GetRenderTree(value.Owner, xforms);
 
             return tree == null ? bounds.CalcBoundingBox() : xforms.GetComponent(tree.Owner).InvWorldMatrix.TransformBox(bounds);

Robust.Client/GameObjects/EntitySystems/SpriteSystem.Specifier.cs

@@ -0,0 +1,84 @@
+using System;
+using JetBrains.Annotations;
+using Robust.Client.Graphics;
+using Robust.Client.ResourceManagement;
+using Robust.Client.Utility;
+using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.Log;
+using Robust.Shared.Map;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Utility;
+
+namespace Robust.Client.GameObjects;
+
+public sealed partial class SpriteSystem
+{
+    [Dependency] private readonly IPrototypeManager _proto = default!;
+    [Dependency] private readonly IResourceCache _resourceCache = default!;
+
+    [Pure]
+    public Texture Frame0(SpriteSpecifier specifier)
+    {
+        return RsiStateLike(specifier).Default;
+    }
+
+    [Pure]
+    public IRsiStateLike RsiStateLike(SpriteSpecifier specifier)
+    {
+        switch (specifier)
+        {
+            case SpriteSpecifier.Texture tex:
+                return tex.GetTexture(_resourceCache);
+
+            case SpriteSpecifier.Rsi rsi:
+                return GetState(rsi);
+
+            case SpriteSpecifier.EntityPrototype prototypeIcon:
+                if (!_proto.TryIndex<EntityPrototype>(prototypeIcon.EntityPrototypeId, out var prototype))
+                {
+                    Logger.Error("Failed to load PrototypeIcon {0}", prototypeIcon.EntityPrototypeId);
+                    return SpriteComponent.GetFallbackState(_resourceCache);
+                }
+
+                return SpriteComponent.GetPrototypeIcon(prototype, _resourceCache);
+
+            default:
+                throw new NotSupportedException();
+        }
+    }
+
+    [Pure]
+    public IRsiStateLike GetPrototypeIcon(EntityPrototype prototype, IResourceCache resourceCache)
+    {
+        var icon = IconComponent.GetPrototypeIcon(prototype, _resourceCache);
+        if (icon != null) return icon;
+
+        if (!prototype.Components.ContainsKey("Sprite"))
+        {
+            return SpriteComponent.GetFallbackState(resourceCache);
+        }
+
+        var dummy = Spawn(prototype.ID, MapCoordinates.Nullspace);
+        var spriteComponent = EnsureComp<SpriteComponent>(dummy);
+        var result = spriteComponent.Icon ?? SpriteComponent.GetFallbackState(resourceCache);
+        Del(dummy);
+
+        return result;
+    }
+
+    [Pure]
+    public RSI.State GetState(SpriteSpecifier.Rsi rsiSpecifier)
+    {
+        if (_resourceCache.TryGetResource<RSIResource>(
+                SharedSpriteComponent.TextureRoot / rsiSpecifier.RsiPath,
+                out var theRsi) &&
+            theRsi.RSI.TryGetState(rsiSpecifier.RsiState, out var state))
+        {
+            return state;
+        }
+
+        Logger.Error("Failed to load RSI {0}", rsiSpecifier.RsiPath);
+        return SpriteComponent.GetFallbackState(_resourceCache);
+    }
+}

Robust.Client/GameObjects/EntitySystems/SpriteSystem.cs

@@ -11,7 +11,7 @@ namespace Robust.Client.GameObjects
     /// Updates the layer animation for every visible sprite.
     /// </summary>
     [UsedImplicitly]
-    public sealed class SpriteSystem : EntitySystem
+    public sealed partial class SpriteSystem : EntitySystem
     {
         [Dependency] private readonly IEyeManager _eyeManager = default!;
         [Dependency] private readonly RenderingTreeSystem _treeSystem = default!;

Robust.Client/GameStates/ClientGameStateManager.cs

@@ -45,7 +45,6 @@ namespace Robust.Client.GameStates
 
         [Dependency] private readonly IComponentFactory _compFactory = default!;
         [Dependency] private readonly IClientEntityManagerInternal _entities = default!;
-        [Dependency] private readonly IEntityLookup _lookup = default!;
         [Dependency] private readonly IPlayerManager _players = default!;
         [Dependency] private readonly IClientNetManager _network = default!;
         [Dependency] private readonly IBaseClient _client = default!;
@@ -332,8 +331,6 @@ namespace Robust.Client.GameStates
             }
 
             _entities.TickUpdate((float) _timing.TickPeriod.TotalSeconds, noPredictions: !IsPredictionEnabled);
-
-            _lookup.Update();
         }
 
         private void ResetPredictedEntities(GameTick curTick)
@@ -424,7 +421,6 @@ namespace Robust.Client.GameStates
             var createdEntities = ApplyEntityStates(curState.EntityStates.Span, curState.EntityDeletions.Span,
                 nextState != null ? nextState.EntityStates.Span : default);
             _players.ApplyPlayerStates(curState.PlayerStates.Value ?? Array.Empty<PlayerState>());
-            _mapManager.ApplyGameStatePost(curState.MapData);
 
             GameStateApplied?.Invoke(new GameStateAppliedArgs(curState));
             return createdEntities;

Robust.Client/Graphics/Audio/ClydeAudio.AudioSources.cs

@@ -15,6 +15,7 @@ using Robust.Shared.IoC;
 using Robust.Shared.Audio;
 using Robust.Shared.Log;
 using Vector2 = Robust.Shared.Maths.Vector2;
+using Robust.Shared.Utility;
 
 namespace Robust.Client.Graphics.Audio
 {
@@ -193,8 +194,10 @@ namespace Robust.Client.Graphics.Audio
                 {
                     _didPositionWarning = true;
                     Logger.WarningS("clyde.oal",
-                        "Attempting to set position on audio source with multiple audio channels! Stream: '{0}'",
+                        "Attempting to set position on audio source with multiple audio channels! Stream: '{0}'.  Make sure the audio is MONO, not stereo.",
                         _sourceStream.Name);
+                    // warning isn't enough, people just ignore it :(
+                    DebugTools.Assert(false, $"Attempting to set position on audio source with multiple audio channels! Stream: '{_sourceStream.Name}'. Make sure the audio is MONO, not stereo.");
                 }
 #endif
 

Robust.Client/Graphics/Clyde/Clyde.GridRendering.cs

@@ -1,7 +1,5 @@
 using System;
-using System.Buffers;
 using System.Collections.Generic;
-using System.Diagnostics;
 using OpenToolkit.Graphics.OpenGL4;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
@@ -18,8 +16,8 @@ namespace Robust.Client.Graphics.Clyde
         private readonly Dictionary<GridId, Dictionary<Vector2i, MapChunkData>> _mapChunkData =
             new();
 
-        private int _verticesPerChunk(IMapChunk chunk) => chunk.ChunkSize * chunk.ChunkSize * 4;
-        private int _indicesPerChunk(IMapChunk chunk) => chunk.ChunkSize * chunk.ChunkSize * GetQuadBatchIndexCount();
+        private int _verticesPerChunk(MapChunk chunk) => chunk.ChunkSize * chunk.ChunkSize * 4;
+        private int _indicesPerChunk(MapChunk chunk) => chunk.ChunkSize * chunk.ChunkSize * GetQuadBatchIndexCount();
 
         private void _drawGrids(Viewport viewport, Box2Rotated worldBounds, IEye eye)
         {
@@ -78,7 +76,7 @@ namespace Robust.Client.Graphics.Clyde
             }
         }
 
-        private void _updateChunkMesh(IMapGrid grid, IMapChunk chunk)
+        private void _updateChunkMesh(IMapGrid grid, MapChunk chunk)
         {
             var data = _mapChunkData[grid.Index];
 
@@ -91,25 +89,41 @@ namespace Robust.Client.Graphics.Clyde
             Span<Vertex2D> vertexBuffer = stackalloc Vertex2D[_verticesPerChunk(chunk)];
 
             var i = 0;
-            foreach (var tile in chunk)
+            var cSz = grid.ChunkSize;
+            var cScaled = chunk.Indices * cSz;
+            for (ushort x = 0; x < cSz; x++)
             {
-                var regionMaybe = _tileDefinitionManager.TileAtlasRegion(tile.Tile);
-                if (regionMaybe == null)
+                for (ushort y = 0; y < cSz; y++)
                 {
-                    continue;
+                    var tile = chunk.GetTile(x, y);
+                    if (tile.IsEmpty)
+                        continue;
+
+                    var regionMaybe = _tileDefinitionManager.TileAtlasRegion(tile);
+
+                    Box2 region;
+                    if (regionMaybe == null || regionMaybe.Length <= tile.Variant)
+                    {
+                        region = _tileDefinitionManager.ErrorTileRegion;
+                    }
+                    else
+                    {
+                        region = regionMaybe[tile.Variant];
+                    }
+
+                    var gx = x + cScaled.X;
+                    var gy = y + cScaled.Y;
+
+                    var vIdx = i * 4;
+                    vertexBuffer[vIdx + 0] = new Vertex2D(gx, gy, region.Left, region.Bottom);
+                    vertexBuffer[vIdx + 1] = new Vertex2D(gx + 1, gy, region.Right, region.Bottom);
+                    vertexBuffer[vIdx + 2] = new Vertex2D(gx + 1, gy + 1, region.Right, region.Top);
+                    vertexBuffer[vIdx + 3] = new Vertex2D(gx, gy + 1, region.Left, region.Top);
+                    var nIdx = i * GetQuadBatchIndexCount();
+                    var tIdx = (ushort)(i * 4);
+                    QuadBatchIndexWrite(indexBuffer, ref nIdx, tIdx);
+                    i += 1;
                 }
-
-                var region = regionMaybe.Value;
-
-                var vIdx = i * 4;
-                vertexBuffer[vIdx + 0] = new Vertex2D(tile.X, tile.Y, region.Left, region.Bottom);
-                vertexBuffer[vIdx + 1] = new Vertex2D(tile.X + 1, tile.Y, region.Right, region.Bottom);
-                vertexBuffer[vIdx + 2] = new Vertex2D(tile.X + 1, tile.Y + 1, region.Right, region.Top);
-                vertexBuffer[vIdx + 3] = new Vertex2D(tile.X, tile.Y + 1, region.Left, region.Top);
-                var nIdx = i * GetQuadBatchIndexCount();
-                var tIdx = (ushort) (i * 4);
-                QuadBatchIndexWrite(indexBuffer, ref nIdx, tIdx);
-                i += 1;
             }
 
             GL.BindVertexArray(datum.VAO);
@@ -122,7 +136,7 @@ namespace Robust.Client.Graphics.Clyde
             datum.TileCount = i;
         }
 
-        private MapChunkData _initChunkBuffers(IMapGrid grid, IMapChunk chunk)
+        private MapChunkData _initChunkBuffers(IMapGrid grid, MapChunk chunk)
         {
             var vao = GenVertexArray();
             BindVertexArray(vao);
@@ -159,7 +173,7 @@ namespace Robust.Client.Graphics.Clyde
             return datum;
         }
 
-        private bool _isChunkDirty(IMapGrid grid, IMapChunk chunk)
+        private bool _isChunkDirty(IMapGrid grid, MapChunk chunk)
         {
             var data = _mapChunkData[grid.Index];
             return !data.TryGetValue(chunk.Indices, out var datum) || datum.Dirty;
@@ -175,7 +189,7 @@ namespace Robust.Client.Graphics.Clyde
             // Don't need to set it if we don't have an entry since lack of an entry is treated as dirty.
         }
 
-        private void _updateOnGridModified(object? sender, GridChangedEventArgs args)
+        private void _updateOnGridModified(GridModifiedEvent args)
         {
             foreach (var (pos, _) in args.Modified)
             {
@@ -185,21 +199,23 @@ namespace Robust.Client.Graphics.Clyde
             }
         }
 
-        private void _updateTileMapOnUpdate(object? sender, TileChangedEventArgs args)
+        private void _updateTileMapOnUpdate(TileChangedEvent args)
         {
             var grid = _mapManager.GetGrid(args.NewTile.GridIndex);
             var chunk = grid.GridTileToChunkIndices(new Vector2i(args.NewTile.X, args.NewTile.Y));
             _setChunkDirty(grid, chunk);
         }
 
-        private void _updateOnGridCreated(MapId mapId, GridId gridId)
+        private void _updateOnGridCreated(GridStartupEvent ev)
         {
+            var gridId = ev.GridId;
             Logger.DebugS("grid", $"Adding {gridId} to grid renderer");
             _mapChunkData.Add(gridId, new Dictionary<Vector2i, MapChunkData>());
         }
 
-        private void _updateOnGridRemoved(MapId mapId, GridId gridId)
+        private void _updateOnGridRemoved(GridRemovalEvent ev)
         {
+            var gridId = ev.GridId;
             Logger.DebugS("grid", $"Removing {gridId} from grid renderer");
 
             var data = _mapChunkData[gridId];

Robust.Client/Graphics/Clyde/Clyde.HLR.cs

@@ -24,11 +24,17 @@ namespace Robust.Client.Graphics.Clyde
     {
         public ClydeDebugLayers DebugLayers { get; set; }
 
-        private readonly RefList<(SpriteComponent sprite, Matrix3 worldMatrix, Angle worldRotation, float yWorldPos)>
+        private readonly RefList<(SpriteComponent sprite, Vector2 worldPos, Angle worldRotation, Box2 spriteScreenBB)>
             _drawingSpriteList
                 =
                 new();
 
+        // TODO allow this scale to be passed with PostShader as variable
+        /// <summary>
+        ///     Some shaders that enlarge the final sprite, like emission or highlight effects, need to use a slightly larger render target.
+        /// </summary>
+        public static float PostShadeScale = 1.25f;
+
         public void Render()
         {
             CheckTransferringScreenshots();
@@ -217,9 +223,8 @@ namespace Robust.Client.Graphics.Clyde
             RenderOverlays(viewport, OverlaySpace.WorldSpaceBelowEntities, worldAABB, worldBounds);
 
             var screenSize = viewport.Size;
-            eye.GetViewMatrix(out var eyeMatrix, eye.Scale);
 
-            ProcessSpriteEntities(mapId, eyeMatrix, worldBounds, _drawingSpriteList);
+            ProcessSpriteEntities(mapId, viewport, eye, worldBounds, _drawingSpriteList);
 
             var worldOverlays = new List<Overlay>();
 
@@ -276,30 +281,12 @@ namespace Robust.Client.Graphics.Clyde
                     break;
                 }
 
-                var matrix = entry.worldMatrix;
-                var worldPosition = new Vector2(matrix.R0C2, matrix.R1C2);
-
                 RenderTexture? entityPostRenderTarget = null;
                 Vector2i roundedPos = default;
                 if (entry.sprite.PostShader != null)
                 {
-                    // calculate world bounding box
-                    var spriteBB = entry.sprite.CalculateBoundingBox(worldPosition);
-                    var spriteLB = spriteBB.BottomLeft;
-                    var spriteRT = spriteBB.TopRight;
-
-                    // finally we can calculate screen bounding in pixels
-                    var screenLB = viewport.WorldToLocal(spriteLB);
-                    var screenRT = viewport.WorldToLocal(spriteRT);
-
-                    // we need to scale RT a for effects like emission or highlight
-                    // scale can be passed with PostShader as variable in future
-                    var postShadeScale = 1.25f;
-                    var screenSpriteSize = (Vector2i) ((screenRT - screenLB) * postShadeScale).Rounded();
-
-                    // Rotate the vector by the eye angle, otherwise the bounding box will be incorrect
-                    screenSpriteSize = (Vector2i) eye.Rotation.RotateVec(screenSpriteSize).Rounded();
-                    screenSpriteSize.Y = -screenSpriteSize.Y;
+                    // get the size of the sprite on screen, scaled slightly to allow for shaders that increase the final sprite size.
+                    var screenSpriteSize = (Vector2i) (entry.spriteScreenBB.Size * PostShadeScale).Rounded();
 
                     // I'm not 100% sure why it works, but without it post-shader
                     // can be lower or upper by 1px than original sprite depending on sprite rotation or scale
@@ -322,16 +309,14 @@ namespace Robust.Client.Graphics.Clyde
                         // Calculate viewport so that the entity thinks it's drawing to the same position,
                         // which is necessary for light application,
                         // but it's ACTUALLY drawing into the center of the render target.
-                        var spritePos = spriteBB.Center;
-                        var screenPos = viewport.WorldToLocal(spritePos);
-                        var (roundedX, roundedY) = roundedPos = (Vector2i) screenPos;
-                        var flippedPos = new Vector2i(roundedX, screenSize.Y - roundedY);
+                        roundedPos = (Vector2i) entry.spriteScreenBB.Center;
+                        var flippedPos = new Vector2i(roundedPos.X, screenSize.Y - roundedPos.Y);
                         flippedPos -= entityPostRenderTarget.Size / 2;
                         _renderHandle.Viewport(Box2i.FromDimensions(-flippedPos, screenSize));
                     }
                 }
 
-                entry.sprite.Render(_renderHandle.DrawingHandleWorld, eye.Rotation, in entry.worldRotation, in worldPosition);
+                entry.sprite.Render(_renderHandle.DrawingHandleWorld, eye.Rotation, in entry.worldRotation, in entry.worldPos);
 
                 if (entry.sprite.PostShader != null && entityPostRenderTarget != null)
                 {
@@ -369,17 +354,26 @@ namespace Robust.Client.Graphics.Clyde
         }
 
         [MethodImpl(MethodImplOptions.NoInlining)]
-        private void ProcessSpriteEntities(MapId map, Matrix3 eyeMatrix, Box2Rotated worldBounds,
-            RefList<(SpriteComponent sprite, Matrix3 matrix, Angle worldRot, float yWorldPos)> list)
+        private void ProcessSpriteEntities(MapId map, Viewport view, IEye eye, Box2Rotated worldBounds,
+            RefList<(SpriteComponent sprite, Vector2 worldPos, Angle worldRot, Box2 spriteScreenBB)> list)
         {
             var xforms = _entityManager.GetEntityQuery<TransformComponent>();
 
+            // Construct a matrix equivalent for Viewport.WorldToLocal()
+            eye.GetViewMatrix(out var viewMatrix, view.RenderScale);
+            var uiProjmatrix = Matrix3.Identity;
+            uiProjmatrix.R0C0 = EyeManager.PixelsPerMeter;
+            uiProjmatrix.R1C1 = -EyeManager.PixelsPerMeter;
+            uiProjmatrix.R0C2 = view.Size.X / 2f;
+            uiProjmatrix.R1C2 = view.Size.Y / 2f;
+            var worldToLocal = viewMatrix * uiProjmatrix;
+
             foreach (var comp in _entitySystemManager.GetEntitySystem<RenderingTreeSystem>().GetRenderTrees(map, worldBounds))
             {
                 var bounds = xforms.GetComponent(comp.Owner).InvWorldMatrix.TransformBox(worldBounds);
 
                 comp.SpriteTree.QueryAabb(ref list, (
-                    ref RefList<(SpriteComponent sprite, Matrix3 matrix, Angle worldRot, float yWorldPos)> state,
+                    ref RefList<(SpriteComponent sprite, Vector2 worldPos, Angle worldRot, Box2 spriteScreenBB)> state,
                     in SpriteComponent value) =>
                 {
                     var entity = value.Owner;
@@ -387,12 +381,10 @@ namespace Robust.Client.Graphics.Clyde
 
                     ref var entry = ref state.AllocAdd();
                     entry.sprite = value;
-                    Vector2 worldPos;
-                    (worldPos, entry.worldRot, entry.matrix) = transform.GetWorldPositionRotationMatrix();
-                    var eyePos = eyeMatrix.Transform(worldPos);
-                    // Didn't use the bounds from the query as that has to be re-calculated (and is probably more expensive than this).
-                    var bounds = value.CalculateBoundingBox(eyePos);
-                    entry.yWorldPos = eyePos.Y - bounds.Extents.Y;
+                    (entry.worldPos, entry.worldRot) = transform.GetWorldPositionRotation();
+
+                    var spriteWorldBB = value.CalculateRotatedBoundingBox(entry.worldPos, entry.worldRot, eye);
+                    entry.spriteScreenBB = worldToLocal.TransformBox(spriteWorldBB);
                     return true;
 
                 }, bounds, true);

Robust.Client/Graphics/Clyde/Clyde.LightRendering.cs

@@ -514,14 +514,14 @@ namespace Robust.Client.Graphics.Clyde
             var enlargedBounds = worldAABB.Enlarged(renderingTreeSystem.MaxLightRadius);
 
             // Use worldbounds for this one as we only care if the light intersects our actual bounds
-            var state = (this, worldAABB, count: 0);
+            var state = (this, worldAABB, count: 0, shadowCastingCount: 0);
             var xforms = _entityManager.GetEntityQuery<TransformComponent>();
 
             foreach (var comp in renderingTreeSystem.GetRenderTrees(map, enlargedBounds))
             {
                 var bounds = xforms.GetComponent(comp.Owner).InvWorldMatrix.TransformBox(worldBounds);
 
-                comp.LightTree.QueryAabb(ref state, (ref (Clyde clyde, Box2 worldAABB, int count) state, in PointLightComponent light) =>
+                comp.LightTree.QueryAabb(ref state, (ref (Clyde clyde, Box2 worldAABB, int count, int shadowCastingCount) state, in PointLightComponent light) =>
                 {
                     if (state.count >= LightsToRenderListSize)
                     {
@@ -543,6 +543,9 @@ namespace Robust.Client.Graphics.Clyde
                         return true;
                     }
 
+                    // If the light is a shadow casting light, keep a separate track of that
+                    if (light.CastShadows) state.shadowCastingCount++;
+
                     float distanceSquared = (state.worldAABB.Center - lightPos).LengthSquared;
                     state.clyde._lightsToRenderList[state.count++] = (light, lightPos, distanceSquared);
 
@@ -550,17 +553,29 @@ namespace Robust.Client.Graphics.Clyde
                 }, bounds);
             }
 
-            if (state.count > _maxLightsPerScene)
+            if (state.shadowCastingCount > _maxLightsPerScene)
             {
-                // There are too many lights to fit in the scene.
+                // There are too many lights casting shadows to fit in the scene.
                 // This check must occur before occluder expansion, or else bad things happen.
-                // Sort lights by distance.
+
+                // First, partition the array based on whether the lights are shadow casting or not
+                // (non shadow casting lights should be the first partition, shadow casting lights the second)
                 Array.Sort(_lightsToRenderList, 0, state.count, Comparer<(PointLightComponent light, Vector2 pos, float distanceSquared)>.Create((x, y) =>
+                {
+                    if (x.light.CastShadows && !y.light.CastShadows) return 1;
+                    else if (!x.light.CastShadows && y.light.CastShadows) return -1;
+                    else return 0;
+                }));
+
+                // Next, sort just the shadow casting lights by distance.
+                Array.Sort(_lightsToRenderList, state.count - state.shadowCastingCount, state.shadowCastingCount, Comparer<(PointLightComponent light, Vector2 pos, float distanceSquared)>.Create((x, y) =>
                 {
                     return x.distanceSquared.CompareTo(y.distanceSquared);
                 }));
-                // Then effectively delete the furthest lights.
-                state.count = _maxLightsPerScene;
+
+                // Then effectively delete the furthest lights, by setting the end of the array to exclude N
+                // number of shadow casting lights (where N is the number above the max number per scene.)
+                state.count -= state.shadowCastingCount - _maxLightsPerScene;
             }
 
             // When culling occluders later, we can't just remove any occluders outside the worldBounds.
@@ -846,7 +861,6 @@ namespace Robust.Client.Graphics.Clyde
             // 3D geometry used during depth projection.
             // 2D mask geometry used to apply wall bleed.
 
-            // TODO: This code probably does not work correctly with rotated camera.
             // TODO: Yes this function throws and index exception if you reach maxOccluders.
 
             const int maxOccluders = 2048;

Robust.Client/Graphics/Clyde/Clyde.Rendering.cs

@@ -994,9 +994,9 @@ namespace Robust.Client.Graphics.Clyde
 
         private sealed class SpriteDrawingOrderComparer : IComparer<int>
         {
-            private readonly RefList<(SpriteComponent, Matrix3, Angle, float)> _drawList;
+            private readonly RefList<(SpriteComponent, Vector2, Angle, Box2)> _drawList;
 
-            public SpriteDrawingOrderComparer(RefList<(SpriteComponent, Matrix3, Angle, float)> drawList)
+            public SpriteDrawingOrderComparer(RefList<(SpriteComponent, Vector2, Angle, Box2)> drawList)
             {
                 _drawList = drawList;
             }
@@ -1019,7 +1019,8 @@ namespace Robust.Client.Graphics.Clyde
                     return cmp;
                 }
 
-                cmp = _drawList[y].Item4.CompareTo(_drawList[x].Item4);
+                // compare the top of the sprite's BB for y-sorting. Because screen coordinates are flipped, the "top" of the BB is actually the "bottom".
+                cmp = _drawList[x].Item4.Top.CompareTo(_drawList[y].Item4.Top);
 
                 if (cmp != 0)
                 {

Robust.Client/Graphics/Clyde/Clyde.Windowing.cs

@@ -437,6 +437,13 @@ namespace Robust.Client.Graphics.Clyde
             _windowing!.WindowSetVisible(reg, visible);
         }
 
+        public void RunOnWindowThread(Action a)
+        {
+            DebugTools.AssertNotNull(_windowing);
+
+            _windowing!.RunOnWindowThread(a);
+        }
+
         private abstract class WindowReg
         {
             public bool IsDisposed;

Robust.Client/Graphics/Clyde/Clyde.cs

@@ -22,7 +22,7 @@ namespace Robust.Client.Graphics.Clyde
     /// <summary>
     ///     Responsible for most things rendering on OpenGL mode.
     /// </summary>
-    internal sealed partial class Clyde : IClydeInternal, IPostInjectInit
+    internal sealed partial class Clyde : IClydeInternal, IPostInjectInit, IEntityEventSubscriber
     {
         [Dependency] private readonly IClydeTileDefinitionManager _tileDefinitionManager = default!;
         [Dependency] private readonly IEyeManager _eyeManager = default!;
@@ -134,16 +134,19 @@ namespace Robust.Client.Graphics.Clyde
 
         public void PostInject()
         {
-            _mapManager.TileChanged += _updateTileMapOnUpdate;
-            _mapManager.OnGridCreated += _updateOnGridCreated;
-            _mapManager.OnGridRemoved += _updateOnGridRemoved;
-            _mapManager.GridChanged += _updateOnGridModified;
-
             // This cvar does not modify the actual GL version requested or anything,
             // it overrides the version we detect to detect GL features.
             RegisterBlockCVars();
         }
 
+        public void RegisterGridEcsEvents()
+        {
+            _entityManager.EventBus.SubscribeEvent<TileChangedEvent>(EventSource.Local, this, _updateTileMapOnUpdate);
+            _entityManager.EventBus.SubscribeEvent<GridStartupEvent>(EventSource.Local, this, _updateOnGridCreated);
+            _entityManager.EventBus.SubscribeEvent<GridRemovalEvent>(EventSource.Local, this, _updateOnGridRemoved);
+            _entityManager.EventBus.SubscribeEvent<GridModifiedEvent>(EventSource.Local, this, _updateOnGridModified);
+        }
+
         private void GLInitBindings(bool gles)
         {
             _glBindingsContext = _glContext!.BindingsContext;

Robust.Client/Graphics/Clyde/ClydeHeadless.cs

@@ -76,6 +76,11 @@ namespace Robust.Client.Graphics.Clyde
             return null;
         }
 
+        public void RegisterGridEcsEvents()
+        {
+            // Nada.
+        }
+
         public void SetWindowTitle(string title)
         {
             // Nada.
@@ -246,6 +251,11 @@ namespace Robust.Client.Graphics.Clyde
             // Nada.
         }
 
+        public void RunOnWindowThread(Action action)
+        {
+            action();
+        }
+
         private sealed class DummyCursor : ICursor
         {
             public void Dispose()

Robust.Client/Graphics/Clyde/Windowing/Glfw.WindowThread.cs

@@ -118,6 +118,10 @@ namespace Robust.Client.Graphics.Clyde
                     case CmdWinCursorSet cmd:
                         WinThreadWinCursorSet(cmd);
                         break;
+
+                    case CmdRunAction cmd:
+                        cmd.Action();
+                        break;
                 }
             }
 
@@ -169,6 +173,11 @@ namespace Robust.Client.Graphics.Clyde
                 }
             }
 
+            public void RunOnWindowThread(Action action)
+            {
+                SendCmd(new CmdRunAction(action));
+            }
+
             private abstract record CmdBase;
 
             private sealed record CmdTerminate : CmdBase;
@@ -245,6 +254,10 @@ namespace Robust.Client.Graphics.Clyde
             private sealed record CmdCursorDestroy(
                 ClydeHandle Cursor
             ) : CmdBase;
+
+            private sealed record CmdRunAction(
+                Action Action
+            ) : CmdBase;
         }
     }
 }

Robust.Client/Graphics/Clyde/Windowing/IWindowingImpl.cs

@@ -1,4 +1,5 @@
-using System.Threading.Tasks;
+using System;
+using System.Threading.Tasks;
 using Robust.Client.Input;
 using Robust.Shared.Maths;
 using SixLabors.ImageSharp;
@@ -58,6 +59,9 @@ namespace Robust.Client.Graphics.Clyde
             void GLMakeContextCurrent(WindowReg? reg);
             void GLSwapInterval(int interval);
             unsafe void* GLGetProcAddress(string procName);
+
+            // Misc
+            void RunOnWindowThread(Action a);
         }
     }
 }

Robust.Client/Graphics/FontManager.cs

@@ -9,6 +9,7 @@ using Robust.Shared.Utility;
 using SharpFont;
 using SixLabors.ImageSharp;
 using SixLabors.ImageSharp.PixelFormats;
+using TerraFX.Interop.Windows;
 
 namespace Robust.Client.Graphics
 {
@@ -58,6 +59,14 @@ namespace Robust.Client.Graphics
             return instance;
         }
 
+        public void ClearFontCache()
+        {
+            foreach (var fontInstance in _loadedInstances)
+            {
+                fontInstance.Value.ClearSizeData();
+            }
+        }
+
         private ScaledFontData _generateScaledDatum(FontInstanceHandle instance, float scale)
         {
             var ftFace = instance.FaceHandle.Face;
@@ -246,6 +255,18 @@ namespace Robust.Client.Graphics
                 FaceHandle = faceHandle;
             }
 
+            public void ClearSizeData()
+            {
+                foreach (var scaleData in _scaledData)
+                {
+                    foreach (var ownedTexture in scaleData.Value.AtlasTextures)
+                    {
+                        ownedTexture.Dispose();
+                    }
+                }
+                _scaledData.Clear();
+            }
+
             public Texture? GetCharTexture(Rune codePoint, float scale)
             {
                 var glyph = GetGlyph(codePoint);

Robust.Client/Graphics/IClydeInternal.cs

@@ -61,5 +61,9 @@ namespace Robust.Client.Graphics
 
         /// <returns>Null if not running on X11.</returns>
         uint? GetX11WindowId();
+
+        void RegisterGridEcsEvents();
+
+        void RunOnWindowThread(Action action);
     }
 }

Robust.Client/Graphics/IFontManager.cs

@@ -5,9 +5,8 @@ namespace Robust.Client.Graphics
 {
     public interface IFontManager
     {
-
+        public void ClearFontCache();
     }
-
     internal interface IFontManagerInternal : IFontManager
     {
         IFontFaceHandle Load(Stream stream);

Robust.Client/Map/ClydeTileDefinitionManager.cs

@@ -1,11 +1,11 @@
 using System;
 using System.Collections.Generic;
-using System.IO;
 using System.Linq;
 using Robust.Client.Graphics;
 using Robust.Client.ResourceManagement;
 using Robust.Client.Utility;
 using Robust.Shared.IoC;
+using Robust.Shared.Log;
 using Robust.Shared.Map;
 using Robust.Shared.Maths;
 using Robust.Shared.Utility;
@@ -22,11 +22,20 @@ namespace Robust.Client.Map
 
         public Texture TileTextureAtlas => _tileTextureAtlas ?? Texture.Transparent;
 
-        private readonly Dictionary<ushort, Box2> _tileRegions = new();
+        private readonly Dictionary<ushort, Box2[]> _tileRegions = new();
 
-        public Box2? TileAtlasRegion(Tile tile)
+        public Box2 ErrorTileRegion { get; private set; }
+
+        /// <inheritdoc />
+        public Box2[]? TileAtlasRegion(Tile tile)
         {
-            if (_tileRegions.TryGetValue(tile.TypeId, out var region))
+            return TileAtlasRegion(tile.TypeId);
+        }
+
+        /// <inheritdoc />
+        public Box2[]? TileAtlasRegion(ushort tileType)
+        {
+            if (_tileRegions.TryGetValue(tileType, out var region))
             {
                 return region;
             }
@@ -51,39 +60,79 @@ namespace Robust.Client.Map
 
             const int tileSize = EyeManager.PixelsPerMeter;
 
-            var dimensionX = (int) Math.Ceiling(Math.Sqrt(defList.Count));
-            var dimensionY = (int) Math.Ceiling((float) defList.Count / dimensionX);
+            var tileCount = defList.Select(x => (int)x.Variants).Sum() + 1;
 
-            var sheet = new Image<Rgba32>(dimensionX * tileSize, dimensionY * tileSize);
+            var dimensionX = (int) Math.Ceiling(Math.Sqrt(tileCount));
+            var dimensionY = (int) Math.Ceiling((float) tileCount / dimensionX);
 
-            for (var i = 0; i < defList.Count; i++)
+            var imgWidth = dimensionX * tileSize;
+            var imgHeight = dimensionY * tileSize;
+            var sheet = new Image<Rgba32>(imgWidth, imgHeight);
+
+            // Add in the missing tile texture sprite as tile texture 0.
             {
-                var def = defList[i];
-                var column = i % dimensionX;
-                var row = i / dimensionX;
+                var w = (float) sheet.Width;
+                var h = (float) sheet.Height;
+                ErrorTileRegion = Box2.FromDimensions(
+                    0, (h - EyeManager.PixelsPerMeter) / h,
+                    tileSize / w, tileSize / h);
+                Image<Rgba32> image;
+                using (var stream = _resourceCache.ContentFileRead("/Textures/noTile.png"))
+                {
+                    image = Image.Load<Rgba32>(stream);
+                }
 
+                image.Blit(new UIBox2i(0, 0, tileSize, tileSize), sheet, Vector2i.Zero);
+            }
+
+            if (imgWidth >= 2048 || imgHeight >= 2048)
+            {
+                // Sanity warning, some machines don't have textures larger than this and need multiple atlases.
+                Logger.WarningS("clyde",
+                    $"Tile texture atlas is ({imgWidth} x {imgHeight}), larger than 2048 x 2048. If you really need {tileCount} tiles, file an issue on RobustToolbox.");
+            }
+
+            var column = 1;
+            var row = 0;
+            foreach (var def in defList)
+            {
                 Image<Rgba32> image;
                 using (var stream = _resourceCache.ContentFileRead(new ResourcePath(def.Path) / $"{def.SpriteName}.png"))
                 {
                     image = Image.Load<Rgba32>(stream);
                 }
 
-                if (image.Width != tileSize || image.Height != tileSize)
+                if (image.Width != (tileSize * def.Variants) || image.Height != tileSize)
                 {
-                    throw new NotSupportedException("Unable to use tiles with a dimension other than 32x32.");
+                    throw new NotSupportedException(
+                        $"Unable to load {new ResourcePath(def.Path) / $"{def.SpriteName}.png"}, due to being unable to use tile texture with a dimension other than {tileSize}x({tileSize} * Variants).");
                 }
 
-                var point = new Vector2i(column * tileSize, row * tileSize);
+                var regionList = new Box2[def.Variants];
 
-                image.Blit(new UIBox2i(0, 0, image.Width, image.Height), sheet, point);
+                for (var j = 0; j < def.Variants; j++)
+                {
+                    var point = new Vector2i(column * tileSize, row * tileSize);
 
-                var w = (float) sheet.Width;
-                var h = (float) sheet.Height;
+                    var box = new UIBox2i(0, 0, tileSize, tileSize).Translated(new Vector2i(j * tileSize, 0));
+                    image.Blit(box, sheet, point);
 
-                _tileRegions.Add(def.TileId,
-                    Box2.FromDimensions(
+                    var w = (float) sheet.Width;
+                    var h = (float) sheet.Height;
+
+                    regionList[j] = Box2.FromDimensions(
                         point.X / w, (h - point.Y - EyeManager.PixelsPerMeter) / h,
-                        tileSize / w, tileSize / h));
+                        tileSize / w, tileSize / h);
+                    column++;
+
+                    if (column >= dimensionX)
+                    {
+                        column = 0;
+                        row++;
+                    }
+                }
+
+                _tileRegions.Add(def.TileId, regionList);
             }
 
             _tileTextureAtlas = Texture.LoadFromImage(sheet, "Tile Atlas");

Robust.Client/Map/IClydeTileDefinitionManager.cs

@@ -1,3 +1,4 @@
+using System.Collections.Generic;
 using Robust.Client.Graphics;
 using Robust.Shared.Map;
 using Robust.Shared.Maths;
@@ -9,6 +10,8 @@ namespace Robust.Client.Map
     /// </summary>
     internal interface IClydeTileDefinitionManager : ITileDefinitionManager
     {
+        Box2 ErrorTileRegion { get; }
+
         /// <summary>
         ///     The texture atlas containing all the tiles.
         /// </summary>
@@ -18,6 +21,12 @@ namespace Robust.Client.Map
         ///     Gets the region inside the texture atlas to use to draw a tile.
         /// </summary>
         /// <returns>If null, do not draw the tile at all.</returns>
-        Box2? TileAtlasRegion(Tile tile);
+        Box2[]? TileAtlasRegion(Tile tile);
+
+        /// <summary>
+        ///     Gets the region inside the texture atlas to use to draw a tile type.
+        /// </summary>
+        /// <returns>If null, do not draw the tile at all.</returns>
+        Box2[]? TileAtlasRegion(ushort tileType);
     }
 }

Robust.Client/Physics/PhysicsSystem.cs

@@ -37,7 +37,7 @@ namespace Robust.Client.Physics
             SimulateWorld((float) diff.TotalSeconds, true);
         }
 
-        protected override void HandleMapCreated(object? sender, MapEventArgs eventArgs)
+        protected override void HandleMapCreated(MapChangedEvent eventArgs)
         {
             if (eventArgs.Map == MapId.Nullspace) return;
             var mapUid = MapManager.GetMapEntityId(eventArgs.Map);

Robust.Client/Placement/Modes/AlignSimilar.cs

@@ -31,7 +31,7 @@ namespace Robust.Client.Placement.Modes
 
             var mapId = MouseCoords.GetMapId(pManager.EntityManager);
 
-            var snapToEntities = IoCManager.Resolve<IEntityLookup>().GetEntitiesInRange(MouseCoords, SnapToRange)
+            var snapToEntities = EntitySystem.Get<EntityLookupSystem>().GetEntitiesInRange(MouseCoords, SnapToRange)
                 .Where(entity => pManager.EntityManager.GetComponent<MetaDataComponent>(entity).EntityPrototype == pManager.CurrentPrototype && pManager.EntityManager.GetComponent<TransformComponent>(entity).MapID == mapId)
                 .OrderBy(entity => (pManager.EntityManager.GetComponent<TransformComponent>(entity).WorldPosition - MouseCoords.ToMapPos(pManager.EntityManager)).LengthSquared)
                 .ToList();

Robust.Client/Placement/Modes/AlignTileEmpty.cs

@@ -53,7 +53,7 @@ namespace Robust.Client.Placement.Modes
             var topRight = new Vector2(CurrentTile.X + 0.99f, CurrentTile.Y + 0.99f);
             var box = new Box2(bottomLeft, topRight);
 
-            return !IoCManager.Resolve<IEntityLookup>().AnyEntitiesIntersecting(map, box);
+            return !EntitySystem.Get<EntityLookupSystem>().AnyEntitiesIntersecting(map, box);
         }
     }
 }

Robust.Client/Placement/PlacementManager.cs

@@ -22,7 +22,7 @@ using Robust.Shared.Utility;
 
 namespace Robust.Client.Placement
 {
-    public sealed partial class PlacementManager : IPlacementManager, IDisposable
+    public sealed partial class PlacementManager : IPlacementManager, IDisposable, IEntityEventSubscriber
     {
         [Dependency] private readonly IClientNetManager NetworkManager = default!;
         [Dependency] public readonly IPlayerManager PlayerManager = default!;
@@ -185,7 +185,7 @@ namespace Robust.Client.Placement
                 _modeDictionary.Add(type.Name, type);
             }
 
-            MapManager.TileChanged += HandleTileChanged;
+            EntityManager.EventBus.SubscribeEvent<TileChangedEvent>(EventSource.Local, this, HandleTileChanged);
 
             _drawOverlay = new PlacementOverlay(this);
             _overlayManager.AddOverlay(_drawOverlay);
@@ -328,7 +328,7 @@ namespace Robust.Client.Placement
             }
         }
 
-        private void HandleTileChanged(object? sender, TileChangedEventArgs args)
+        private void HandleTileChanged(TileChangedEvent args)
         {
             var coords = MapManager.GetGrid(args.NewTile.GridIndex).GridTileToLocal(args.NewTile.GridIndices);
             _pendingTileChanges.RemoveAll(c => c.Item1 == coords);

Robust.Client/ResourceManagement/ResourceTypes/RSIResource.cs

@@ -230,7 +230,7 @@ namespace Robust.Client.ResourceManagement
 
             using (var manifestFile = cache.ContentFileRead(manifestPath))
             {
-                if (manifestFile.Length <= 4096)
+                if (manifestFile.CanSeek && manifestFile.Length <= 4096)
                 {
                     // Most RSIs are actually tiny so if that's the case just load them into a stackalloc buffer.
                     // Avoids a ton of allocations with stream reader etc

Robust.Client/Robust.Client.csproj

@@ -13,8 +13,8 @@
   <Import Project="..\MSBuild\Robust.DefineConstants.targets" />
   <ItemGroup>
     <PackageReference Include="DiscordRichPresence" Version="1.0.175" />
-    <PackageReference Include="JetBrains.Annotations" Version="2020.3.0" PrivateAssets="All" />
-    <PackageReference Include="Microsoft.Data.Sqlite" Version="5.0.3" />
+    <PackageReference Include="JetBrains.Annotations" Version="2021.3.0" PrivateAssets="All" />
+    <PackageReference Include="Microsoft.Data.Sqlite" Version="6.0.2" />
     <PackageReference Include="nfluidsynth" Version="0.3.1" />
     <PackageReference Include="NVorbis" Version="0.10.1" />
     <PackageReference Include="SixLabors.ImageSharp" Version="1.0.4" />
@@ -25,9 +25,9 @@
     <PackageReference Include="TerraFX.Interop.Windows" Version="10.0.20348-rc2" />
   </ItemGroup>
   <ItemGroup Condition="'$(EnableClientScripting)' == 'True'">
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Features" Version="3.8.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Scripting" Version="3.8.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="3.8.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Features" Version="4.0.1" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Scripting" Version="4.0.1" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.0.1" />
 
     <ProjectReference Include="..\Robust.Shared.Scripting\Robust.Shared.Scripting.csproj" />
   </ItemGroup>
@@ -53,6 +53,7 @@
     <Compile Update="UserInterface\CustomControls\DefaultWindow.xaml.cs">
       <DependentUpon>DefaultWindow.xaml</DependentUpon>
     </Compile>
+    <Compile Remove="Debugging\IDebugDrawing.cs" />
   </ItemGroup>
   <Import Project="..\MSBuild\Robust.Engine.targets" />
   <PropertyGroup>

Robust.Client/UserInterface/Controls/WindowRoot.cs

@@ -1,4 +1,6 @@
 using Robust.Client.Graphics;
+using Robust.Shared.Maths;
+using Robust.Shared.ViewVariables;
 
 namespace Robust.Client.UserInterface.Controls
 {
@@ -9,6 +11,30 @@ namespace Robust.Client.UserInterface.Controls
             Window = window;
         }
 
+        /// <summary>
+        ///     Enable the UI autoscale system, this will scale down the UI for lower resolutions
+        /// </summary>
+        [ViewVariables]
+        public bool AutoScale { get; set; } = false;
+
+        /// <summary>
+        ///     Minimum resolution to start clamping autoscale to 1
+        /// </summary>
+        [ViewVariables]
+        public Vector2i AutoScaleUpperCutoff { get; set; } = new Vector2i(1080, 720);
+
+        /// <summary>
+        ///     Maximum resolution to start clamping autos scale to autoscale minimum
+        /// </summary>
+        [ViewVariables]
+        public Vector2i AutoScaleLowerCutoff { get; set; } = new Vector2i(520, 520);
+
+        /// <summary>
+        ///     The minimum ui scale value that autoscale will scale to
+        /// </summary>
+        [ViewVariables]
+        public float AutoScaleMinimum { get; set; } = 0.5f;
+
         public override float UIScale => UIScaleSet;
         internal float UIScaleSet { get; set; }
         public override IClydeWindow Window { get; }

Robust.Client/UserInterface/FileDialogManager.cs

@@ -8,6 +8,7 @@ using System.Text;
 using System.Threading.Tasks;
 using Robust.Client.Graphics;
 using Robust.Shared;
+using Robust.Shared.Console;
 using Robust.Shared.Asynchronous;
 using Robust.Shared.IoC;
 using Robust.Shared.Log;
@@ -164,12 +165,11 @@ namespace Robust.Client.UserInterface
         {
             if (OperatingSystem.IsMacOS())
             {
-                // macOS seems pretty annoying about having the file dialog opened from the main thread.
-                // So we are forced to execute this synchronously on the main thread.
-                // Also I'm calling RunOnMainThread here to provide safety in case this is ran from a different thread.
-                // nativefiledialog doesn't provide any form of async API, so this WILL lock up the client.
+                // macOS seems pretty annoying about having the file dialog opened from the main windowing thread.
+                // So we are forced to execute this synchronously on the main windowing thread.
+                // nativefiledialog doesn't provide any form of async API, so this WILL lock up half the client.
                 var tcs = new TaskCompletionSource<string?>();
-                _taskManager.RunOnMainThread(() => tcs.SetResult(action()));
+                _clyde.RunOnWindowThread(() => tcs.SetResult(action()));
 
                 return tcs.Task;
             }
@@ -388,4 +388,17 @@ namespace Robust.Client.UserInterface
             SW_NFD_CANCEL,
         }
     }
+
+    public sealed class OpenFileCommand : IConsoleCommand
+    {
+        public string Command => "testopenfile";
+        public string Description => "";
+        public string Help => "";
+
+        public async void Execute(IConsoleShell shell, string argStr, string[] args)
+        {
+            var stream = await IoCManager.Resolve<IFileDialogManager>().OpenFile();
+            stream?.Dispose();
+        }
+    }
 }

Robust.Client/UserInterface/UserInterfaceManager.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using Robust.Client.Graphics;
@@ -23,6 +23,7 @@ namespace Robust.Client.UserInterface
     internal sealed class UserInterfaceManager : IUserInterfaceManagerInternal
     {
         [Dependency] private readonly IInputManager _inputManager = default!;
+        [Dependency] private readonly IFontManager _fontManager = default!;
         [Dependency] private readonly IClydeInternal _clyde = default!;
         [Dependency] private readonly IGameTiming _gameTiming = default!;
         [Dependency] private readonly IPlayerManager _playerManager = default!;
@@ -371,16 +372,21 @@ namespace Robust.Client.UserInterface
                 }
             }
 
-            ReleaseKeyboardFocus();
 
             if (hit == null)
             {
+                ReleaseKeyboardFocus();
                 hitData = null;
                 return false;
             }
 
             var (control, rel) = hit.Value;
 
+            if (control != KeyboardFocused)
+            {
+                ReleaseKeyboardFocus();
+            }
+
             ControlFocused = control;
 
             if (ControlFocused.CanKeyboardFocus && ControlFocused.KeyboardFocusOnClick)
@@ -951,14 +957,37 @@ namespace Robust.Client.UserInterface
         private void WindowContentScaleChanged(WindowContentScaleEventArgs args)
         {
             if (_windowsToRoot.TryGetValue(args.Window.Id, out var root))
+            {
                 UpdateUIScale(root);
+                _fontManager.ClearFontCache();
+            }
+
+        }
+
+        private float CalculateAutoScale(WindowRoot root)
+        {
+            //Grab the OS UIScale or the value set through CVAR debug
+            var osScale = _configurationManager.GetCVar(CVars.DisplayUIScale);
+            osScale = osScale == 0f ? root.Window.ContentScale.X : osScale;
+            var windowSize = root.Window.RenderTarget.Size;
+            //Only run autoscale if it is enabled, otherwise default to just use OS UIScale
+            if (!root.AutoScale && (windowSize.X <= 0 || windowSize.Y <= 0)) return osScale;
+            var maxScaleRes = root.AutoScaleUpperCutoff;
+            var minScaleRes = root.AutoScaleLowerCutoff;
+            var autoScaleMin = root.AutoScaleMinimum;
+            float scaleRatioX;
+            float scaleRatioY;
+
+            //Calculate the scale ratios and clamp it between the maximums and minimums
+            scaleRatioX = Math.Clamp(((float) windowSize.X - minScaleRes.X) / (maxScaleRes.X - minScaleRes.X) * osScale, autoScaleMin, osScale);
+            scaleRatioY = Math.Clamp(((float) windowSize.Y - minScaleRes.Y) / (maxScaleRes.Y - minScaleRes.Y) * osScale, autoScaleMin, osScale);
+            //Take the smallest UIScale value and use it for UI scaling
+            return Math.Min(scaleRatioX, scaleRatioY);
         }
 
         private void UpdateUIScale(WindowRoot root)
         {
-            var newVal = _configurationManager.GetCVar(CVars.DisplayUIScale);
-            root.UIScaleSet = newVal == 0f ? root.Window.ContentScale.X : newVal;
-
+            root.UIScaleSet = CalculateAutoScale(root);
             _propagateUIScaleChanged(root);
             root.InvalidateMeasure();
         }
@@ -977,7 +1006,7 @@ namespace Robust.Client.UserInterface
         {
             if (!_windowsToRoot.TryGetValue(windowResizedEventArgs.Window.Id, out var root))
                 return;
-
+            UpdateUIScale(root);
             root.InvalidateMeasure();
         }
 

Robust.Client/Utility/SpriteSpecifierExt.cs

@@ -22,6 +22,7 @@ namespace Robust.Client.Utility
                 .Texture;
         }
 
+        [Obsolete("Use SpriteSystem")]
         public static RSI.State GetState(this SpriteSpecifier.Rsi rsiSpecifier, IResourceCache cache)
         {
             if (cache.TryGetResource<RSIResource>(
@@ -36,6 +37,7 @@ namespace Robust.Client.Utility
             return SpriteComponent.GetFallbackState(cache);
         }
 
+        [Obsolete("Use SpriteSystem")]
         public static Texture Frame0(this SpriteSpecifier specifier)
         {
             return specifier.RsiStateLike().Default;
@@ -80,6 +82,7 @@ namespace Robust.Client.Utility
             return specifier.RsiStateLike();
         }
 
+        [Obsolete("Use SpriteSystem")]
         public static IRsiStateLike RsiStateLike(this SpriteSpecifier specifier)
         {
             var resC = IoCManager.Resolve<IResourceCache>();

Robust.Docfx/articles/example-article.md

@@ -0,0 +1 @@
+# Add your introductions here!

Robust.Docfx/articles/toc.yml

@@ -0,0 +1,2 @@
+- name: Example-article
+  href: example-article.md

Robust.Docfx/docfx.json

@@ -0,0 +1,214 @@
+{
+  "metadata": [
+    {
+      "src":
+      [
+        {
+          "files": [
+            "**.csproj"
+          ],
+          "exclude": [
+            "**/bin/**",
+            "**/obj/**",
+            "_site/**",
+            "**.xaml"
+          ],
+          "src": "../Robust.UnitTesting"
+        }
+      ],
+      "disableGitFeatures": false,
+      "disableDefaultFilter": false,
+      "dest": "api/Robust.UnitTesting"
+    },
+    {
+      "src":
+      [
+        {
+          "files": [
+            "**.csproj"
+          ],
+          "exclude": [
+            "**/bin/**",
+            "**/obj/**",
+            "_site/**",
+            "**.xaml"
+          ],
+          "src": "../Robust.Shared"
+        }
+      ],
+      "disableGitFeatures": false,
+      "disableDefaultFilter": false,
+      "dest": "api/Robust.Shared"
+    },
+    {
+      "src":
+      [
+        {
+          "files": [
+            "**.csproj"
+          ],
+          "exclude": [
+            "**/bin/**",
+            "**/obj/**",
+            "_site/**",
+            "**.xaml"
+          ],
+          "src": "../Robust.Shared.Maths"
+        }
+      ],
+      "disableGitFeatures": false,
+      "disableDefaultFilter": false,
+      "dest": "api/Robust.Shared.Maths"
+    },
+    {
+      "src":
+      [
+        {
+          "files": [
+            "**.csproj"
+          ],
+          "exclude": [
+            "**/bin/**",
+            "**/obj/**",
+            "_site/**",
+            "**.xaml"
+          ],
+          "src": "../Robust.Shared.Scripting"
+        }
+      ],
+      "disableGitFeatures": false,
+      "disableDefaultFilter": false,
+      "dest": "api/Robust.Shared.Scripting"
+    },
+    {
+      "src":
+      [
+        {
+          "files": [
+            "**.csproj"
+          ],
+          "exclude": [
+            "**/bin/**",
+            "**/obj/**",
+            "_site/**",
+            "**.xaml"
+          ],
+          "src": "../Robust.Client"
+        }
+      ],
+      "disableGitFeatures": false,
+      "disableDefaultFilter": false,
+      "dest": "api/Robust.Client"
+    },
+    {
+      "src":
+      [
+        {
+          "files": [
+            "**.csproj"
+          ],
+          "exclude": [
+            "**/bin/**",
+            "**/obj/**",
+            "_site/**",
+            "**.xaml"
+          ],
+          "src": "../Robust.Client.WebView"
+        }
+      ],
+      "disableGitFeatures": false,
+      "disableDefaultFilter": false,
+      "dest": "api/Robust.Client.WebView"
+    },
+    {
+      "src":
+      [
+        {
+          "files": [
+            "**.csproj"
+          ],
+          "exclude": [
+            "**/bin/**",
+            "**/obj/**",
+            "_site/**",
+            "**.xaml"
+          ],
+          "src": "../Robust.Server"
+        }
+      ],
+      "disableGitFeatures": false,
+      "disableDefaultFilter": false,
+      "dest": "api/Robust.Server"
+    },
+    {
+      "src":
+      [
+        {
+          "files": [
+            "**.csproj"
+          ],
+          "exclude": [
+            "**/bin/**",
+            "**/obj/**",
+            "_site/**",
+            "**.xaml"
+          ],
+          "src": "../Robust.LoaderApi"
+        }
+      ],
+      "disableGitFeatures": false,
+      "disableDefaultFilter": false,
+      "dest": "api/Robust.LoaderApi/Robust.LoaderApi"
+    }
+  ],
+  "build": {
+    "content": [
+      {
+        "files": [
+          "api/**/**.yml"
+        ]
+      },
+      {
+        "files": [
+          "articles/**.md",
+          "articles/**/toc.yml",
+          "toc.yml",
+          "*.md"
+        ]
+      }
+    ],
+    "resource": [
+      {
+        "files": [
+          "images/**",
+          "favicon.ico",
+          "icon.svg"          
+        ]
+      }
+    ],
+    "overwrite": [
+      {
+        "files": [
+          "apidoc/**.md"
+        ],
+        "exclude": [
+          "obj/**",
+          "_site/**"
+        ]
+      }
+    ],
+    "dest": "_robust-site",
+    "globalMetadataFiles": [],
+    "fileMetadataFiles": [],
+    "template": [
+      "default",
+      "templates/darkfx"
+    ],
+    "postProcessors": [],
+    "markdownEngineName": "markdig",
+    "noLangKeyword": false,
+    "keepFileLink": false,
+    "cleanupCacheHistory": false,
+    "disableGitFeatures": false
+  }
+}

Robust.Docfx/index.md

@@ -0,0 +1,6 @@
+# RobustToolbox DocFX
+![](https://i.imgur.com/Sv3Swxg.png)
+
+## Welcome to the RobustToolbox DocFX instance.
+### Click one of the tabs above to see documentation for that particular project/namespace
+

Robust.Docfx/templates/darkfx/LICENSE.txt

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 Steffen Wilke
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

Robust.Docfx/templates/darkfx/partials/affix.tmpl.partial

@@ -0,0 +1,40 @@
+{{!Copyright (c) Microsoft. All rights reserved. Licensed under the MIT license. See LICENSE file in the project root for full license information.}}
+
+<div class="hidden-sm col-md-2" role="complementary">
+  <div class="sideaffix">
+    {{^_disableContribution}}
+    <div class="contribution">
+      <ul class="nav">
+        {{#docurl}}
+        <li>
+          <a href="{{docurl}}" class="contribution-link">{{__global.improveThisDoc}}</a>
+        </li>
+        {{/docurl}}
+        {{#sourceurl}}
+        <li>
+          <a href="{{sourceurl}}" class="contribution-link">{{__global.viewSource}}</a>
+        </li>
+        {{/sourceurl}}
+      </ul>
+    </div>
+    {{/_disableContribution}}
+    <div class="toggle-mode">
+      <div class="icon">
+        <i aria-hidden="true">☀</i>
+      </div>
+      <label class="switch">
+        <input type="checkbox" id="switch-style">
+        <span class="slider round"></span>
+      </label>
+      <div class="icon">
+        <i aria-hidden="true">☾</i>
+      </div>
+    </div>
+
+    <nav class="bs-docs-sidebar hidden-print hidden-xs hidden-sm affix" id="affix">
+    <h5>{{__global.inThisArticle}}</h5>
+    <div></div>
+    <!-- <p><a class="back-to-top" href="#top">Back to top</a><p> -->
+    </nav>
+  </div>
+</div>

Robust.Docfx/templates/darkfx/partials/class.header.tmpl.partial

@@ -0,0 +1,108 @@
+{{!Copyright (c) Microsoft. All rights reserved. Licensed under the MIT license. See LICENSE file in the project root for full license information.}}
+
+<h1 id="{{id}}" data-uid="{{uid}}" class="text-break">{{>partials/title}}</h1>
+<div class="markdown level0 summary">{{{summary}}}</div>
+<div class="markdown level0 conceptual">{{{conceptual}}}</div>
+{{#inClass}}
+<div class="inheritance">
+  <h5>{{__global.inheritance}}</h5>
+  {{#inheritance}}
+  <div class="level{{index}}">{{{specName.0.value}}}</div>
+  {{/inheritance}}
+  <div class="level{{level}}"><span class="xref">{{name.0.value}}</span></div>
+  {{#derivedClasses}}
+    <div class="level{{index}}">{{{specName.0.value}}}</div>
+  {{/derivedClasses}}
+</div>
+{{/inClass}}
+{{#implements.0}}
+<div classs="implements">
+  <h5>{{__global.implements}}</h5>
+{{/implements.0}}
+{{#implements}}
+  <div>{{{specName.0.value}}}</div>
+{{/implements}}
+{{#implements.0}}
+</div>
+{{/implements.0}}
+{{#inheritedMembers.0}}
+<div class="inheritedMembers">
+</div>
+{{/inheritedMembers.0}}
+<h6><strong>{{__global.namespace}}</strong>: {{{namespace.specName.0.value}}}</h6>
+<h6><strong>{{__global.assembly}}</strong>: {{assemblies.0}}.dll</h6>
+<h5 id="{{id}}_syntax">{{__global.syntax}}</h5>
+<div class="codewrapper">
+  <pre><code class="lang-{{_lang}} hljs">{{syntax.content.0.value}}</code></pre>
+</div>
+{{#syntax.parameters.0}}
+<h5 class="parameters">{{__global.parameters}}</h5>
+<table class="table table-bordered table-striped table-condensed">
+  <thead>
+    <tr>
+      <th>{{__global.type}}</th>
+      <th>{{__global.name}}</th>
+      <th>{{__global.description}}</th>
+    </tr>
+  </thead>
+  <tbody>
+{{/syntax.parameters.0}}
+{{#syntax.parameters}}
+    <tr>
+      <td>{{{type.specName.0.value}}}</td>
+      <td><span class="parametername">{{{id}}}</span></td>
+      <td>{{{description}}}</td>
+    </tr>
+{{/syntax.parameters}}
+{{#syntax.parameters.0}}
+  </tbody>
+</table>
+{{/syntax.parameters.0}}
+{{#syntax.return}}
+<h5 class="returns">{{__global.returns}}</h5>
+<table class="table table-bordered table-striped table-condensed">
+  <thead>
+    <tr>
+      <th>{{__global.type}}</th>
+      <th>{{__global.description}}</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td>{{{type.specName.0.value}}}</td>
+      <td>{{{description}}}</td>
+    </tr>
+  </tbody>
+</table>
+{{/syntax.return}}
+{{#syntax.typeParameters.0}}
+<h5 class="typeParameters">{{__global.typeParameters}}</h5>
+<table class="table table-bordered table-striped table-condensed">
+  <thead>
+    <tr>
+      <th>{{__global.name}}</th>
+      <th>{{__global.description}}</th>
+    </tr>
+  </thead>
+  <tbody>
+{{/syntax.typeParameters.0}}
+{{#syntax.typeParameters}}
+    <tr>
+      <td><span class="parametername">{{{id}}}</span></td>
+      <td>{{{description}}}</td>
+    </tr>
+{{/syntax.typeParameters}}
+{{#syntax.typeParameters.0}}
+  </tbody>
+</table>
+{{/syntax.typeParameters.0}}
+{{#remarks}}
+<h5 id="{{id}}_remarks"><strong>{{__global.remarks}}</strong></h5>
+<div class="markdown level0 remarks">{{{remarks}}}</div>
+{{/remarks}}
+{{#example.0}}
+<h5 id="{{id}}_examples"><strong>{{__global.examples}}</strong></h5>
+{{/example.0}}
+{{#example}}
+{{{.}}}
+{{/example}}

Robust.Docfx/templates/darkfx/partials/footer.tmpl.partial

@@ -0,0 +1,29 @@
+{{!Copyright (c) Microsoft. All rights reserved. Licensed under the MIT license. See LICENSE file in the project root for full license information.}}
+
+<footer>
+  <div class="grad-bottom"></div>
+  <div class="footer">
+    <div class="container">
+      <span class="pull-right">
+        <a href="#top">Back to top</a>
+      </span>
+      <div class="pull-left">
+        {{{_appFooter}}}
+        {{^_appFooter}}<span>Generated by <strong>DocFX</strong></span>{{/_appFooter}}
+      </div>
+      <div class="toggle-mode pull-right visible-sm visible-xs">
+        <div class="icon">
+          <i aria-hidden="true">☀</i>
+        </div>
+        <label class="switch">
+          <input type="checkbox" id="switch-style-m">
+          <span class="slider round"></span>
+        </label>
+        <div class="icon">
+          <i aria-hidden="true">☾</i>
+        </div>
+      </div>
+    </div>
+  </div>
+  <script type="text/javascript" src="{{_rel}}styles/toggle-theme.js"></script>
+</footer>

Robust.Docfx/templates/darkfx/partials/head.tmpl.partial

@@ -0,0 +1,20 @@
+{{!Copyright (c) Oscar Vasquez. All rights reserved. Licensed under the MIT license. See LICENSE file in the project root for full license information.}}
+
+<head>
+  <meta charset="utf-8">
+  <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
+  <title>{{#title}}{{title}}{{/title}}{{^title}}{{>partials/title}}{{/title}} {{#_appTitle}}| {{_appTitle}} {{/_appTitle}}</title>
+  <meta name="viewport" content="width=device-width">
+  <meta name="title" content="{{#title}}{{title}}{{/title}}{{^title}}{{>partials/title}}{{/title}} {{#_appTitle}}| {{_appTitle}} {{/_appTitle}}">
+  <meta name="generator" content="docfx {{_docfxVersion}}">
+  {{#_description}}<meta name="description" content="{{_description}}">{{/_description}}
+  <link rel="shortcut icon" href="{{_rel}}{{{_appFaviconPath}}}{{^_appFaviconPath}}favicon.ico{{/_appFaviconPath}}">
+  <link rel="stylesheet" href="{{_rel}}styles/docfx.vendor.css">
+  <link rel="stylesheet" href="{{_rel}}styles/docfx.css">
+  <link rel="stylesheet" href="{{_rel}}styles/main.css">
+  <meta property="docfx:navrel" content="{{_navRel}}">
+  <meta property="docfx:tocrel" content="{{_tocRel}}">
+  {{#_noindex}}<meta name="searchOption" content="noindex">{{/_noindex}}
+  {{#_enableSearch}}<meta property="docfx:rel" content="{{_rel}}">{{/_enableSearch}}
+  {{#_enableNewTab}}<meta property="docfx:newtab" content="true">{{/_enableNewTab}}
+</head>

Robust.Docfx/templates/darkfx/styles/main.css

@@ -0,0 +1,470 @@
+:root, body.dark-theme {
+  --color-foreground: #ccd5dc;
+  --color-navbar: #66666d;
+  --color-breadcrumb: #999;
+  --color-underline: #ddd;
+  --color-toc-hover: #fff;
+  --color-background: #2d2d30;
+  --color-background-subnav: #333337;
+  --color-background-dark: #1e1e1e;
+  --color-background-table-alt: #212123;
+  --color-background-quote: #69696e;
+}
+
+body.light-theme {
+  --color-foreground: #171717;
+  --color-breadcrumb: #4a4a4a;
+  --color-toc-hover: #4c4c4c;
+  --color-background: #ffffff;
+  --color-background-subnav: #f5f5f5;
+  --color-background-dark: #ddd;
+  --color-background-table-alt: #f9f9f9;
+}
+
+body {
+  color: var(--color-foreground);
+  line-height: 1.5;
+  font-size: 14px;
+  -ms-text-size-adjust: 100%;
+  -webkit-text-size-adjust: 100%;
+  word-wrap: break-word;
+  background-color: var(--color-background);
+}
+
+.btn.focus, .btn:focus, .btn:hover {
+  color: var(--color-foreground);
+}
+
+h1 {
+  font-weight: 600;
+  font-size: 32px;
+}
+
+h2 {
+  font-weight: 600;
+  font-size: 24px;
+  line-height: 1.8;
+}
+
+h3 {
+  font-weight: 600;
+  font-size: 20px;
+  line-height: 1.8;
+}
+
+h5 {
+  font-size: 14px;
+  padding: 10px 0px;
+}
+
+article h1, article h2, article h3, article h4 {
+  margin-top: 35px;
+  margin-bottom: 15px;
+}
+
+article h4 {
+  padding-bottom: 8px;
+  border-bottom: 2px solid var(--color-underline);
+}
+
+.navbar-brand>img {
+  color: var(--color-background);
+}
+
+.navbar {
+  border: none;
+}
+
+.subnav {
+  border-top: 1px solid var(--color-underline);
+  background-color: var(--color-background-subnav);
+}
+
+.sidenav, .fixed_header, .toc {
+  background-color: var(--color-background);
+}
+
+.navbar-inverse {
+  background-color: var(--color-background-dark);
+  z-index: 100;
+}
+
+.navbar-inverse .navbar-nav>li>a, .navbar-inverse .navbar-text {
+  color: var(--color-navbar);
+  background-color: var(--color-background-dark);
+  border-bottom: 3px solid transparent;
+  padding-bottom: 12px;
+}
+
+.navbar-inverse .navbar-nav>li>a:focus, .navbar-inverse .navbar-nav>li>a:hover {
+  color: var(--color-foreground);
+  background-color: var(--color-background-dark);
+  border-bottom: 3px solid var(--color-background-subnav);
+  transition: all ease 0.25s;
+}
+
+.navbar-inverse .navbar-nav>.active>a, .navbar-inverse .navbar-nav>.active>a:focus, .navbar-inverse .navbar-nav>.active>a:hover {
+  color: var(--color-foreground);
+  background-color: var(--color-background-dark);
+  border-bottom: 3px solid var(--color-foreground);
+  transition: all ease 0.25s;
+}
+
+.navbar-form .form-control {
+  border: none;
+  border-radius: 0;
+}
+
+.light-theme .navbar-brand svg {
+  filter: brightness(20%);
+}
+
+.toc .level1>li {
+  font-weight: 400;
+}
+
+.toc .nav>li>a {
+  color: var(--color-foreground);
+}
+
+.sidefilter {
+  background-color: var(--color-background);
+  border-left: none;
+  border-right: none;
+}
+
+.sidefilter {
+  background-color: var(--color-background);
+  border-left: none;
+  border-right: none;
+}
+
+.toc-filter {
+  padding: 10px;
+  margin: 0;
+  background-color: var(--color-background);
+}
+
+.toc-filter>input {
+  border: none;
+  border-radius: unset;
+  background-color: var(--color-background-subnav);
+  padding: 5px 0 5px 20px;
+  font-size: 90%
+}
+
+.toc-filter>.clear-icon {
+  position: absolute;
+  top: 17px;
+  right: 15px;
+}
+
+.toc-filter>input:focus {
+  color: var(--color-foreground);
+  transition: all ease 0.25s;
+}
+
+.toc-filter>.filter-icon {
+  display: none;
+}
+
+.sidetoc>.toc {
+  background-color: var(--color-background);
+  overflow-x: hidden;
+}
+
+.sidetoc {
+  background-color: var(--color-background);
+  border: none;
+}
+
+.alert {
+  background-color: inherit;
+  border: none;
+  padding: 10px 0;
+  border-radius: 0;
+}
+
+.alert>p {
+  margin-bottom: 0;
+  padding: 5px 10px;
+  border-bottom: 1px solid;
+  background-color: var(--color-background-dark);
+}
+
+.alert>h5 {
+  padding: 10px 15px;
+  margin-top: 0;
+  margin-bottom: 0;
+  text-transform: uppercase;
+  font-weight: bold;
+  border-top: 2px solid;
+  background-color: var(--color-background-dark);
+  border-radius: none;
+}
+
+.alert>ul {
+  margin-bottom: 0;
+  padding: 5px 40px;
+}
+
+.alert-info {
+  color: #1976d2;
+}
+
+.alert-warning {
+  color: #f57f17;
+}
+
+.alert-danger {
+  color: #d32f2f;
+}
+
+pre {
+  padding: 9.5px;
+  margin: 0 0 10px;
+  font-size: 13px;
+  word-break: break-all;
+  word-wrap: break-word;
+  background-color: var(--color-background-dark);
+  border-radius: 0;
+  border: none;
+}
+
+code {
+  background: var(--color-background-dark) !important;
+  border-radius: 2px;
+}
+
+.hljs {
+  color: var(--color-foreground);
+}
+
+.toc .nav>li.active>.expand-stub::before, .toc .nav>li.in>.expand-stub::before, .toc .nav>li.in.active>.expand-stub::before, .toc .nav>li.filtered>.expand-stub::before {
+  content: "▾";
+}
+
+.toc .nav>li>.expand-stub::before, .toc .nav>li.active>.expand-stub::before {
+  content: "▸";
+}
+
+.affix ul ul>li>a:before {
+  content: "|";
+}
+
+.breadcrumb {
+  background-color: var(--color-background-subnav);
+}
+
+.breadcrumb .label.label-primary {
+  background: #444;
+  border-radius: 0;
+  font-weight: normal;
+  font-size: 100%;
+}
+
+#breadcrumb .breadcrumb>li a {
+  border-radius: 0;
+  font-weight: normal;
+  font-size: 85%;
+  display: inline;
+  padding: 0 .6em 0;
+  line-height: 1;
+  text-align: center;
+  white-space: nowrap;
+  vertical-align: baseline;
+  color: var(--color-breadcrumb);
+}
+
+#breadcrumb .breadcrumb>li a:hover {
+  color: var(--color-foreground);
+  transition: all ease 0.25s;
+}
+
+.breadcrumb>li+li:before {
+  content: "⯈";
+  font-size: 75%;
+  color: var(--color-background-dark);
+  padding: 0;
+}
+
+.light-theme .breadcrumb>li+li:before {
+  color: var(--color-foreground)
+ }
+
+.toc .level1>li {
+  font-weight: 600;
+  font-size: 130%;
+  padding-left: 5px;
+}
+
+.footer {
+  border-top: none;
+  background-color: var(--color-background-dark);
+  padding: 15px 0;
+  font-size: 90%;
+}
+
+.toc .nav>li>a:hover, .toc .nav>li>a:focus {
+  color: var(--color-toc-hover);
+  transition: all ease 0.1s;
+}
+
+.form-control {
+  background-color: var(--color-background-subnav);
+  border: none;
+  border-radius: 0;
+  -webkit-box-shadow: none;
+  box-shadow: none;
+}
+
+.form-control:focus {
+  border-color: #66afe9;
+  outline: 0;
+  -webkit-box-shadow: none;
+  box-shadow: none;
+}
+
+input#search-query:focus {
+  color: var(--color-foreground);
+}
+
+.table-bordered, .table-bordered>tbody>tr>td, .table-bordered>tbody>tr>th, .table-bordered>tfoot>tr>td, .table-bordered>tfoot>tr>th, .table-bordered>thead>tr>td, .table-bordered>thead>tr>th {
+  border: 1px solid var(--color-background-dark);
+}
+
+.table-striped>tbody>tr:nth-of-type(odd) {
+  background-color: var(--color-background-table-alt);
+}
+
+blockquote {
+  padding: 10px 20px;
+  margin: 0 0 10px;
+  font-size: 110%;
+  border-left: 5px solid var(--color-background-quote);
+  color: var(--color-background-quote);
+}
+
+.pagination>.disabled>a, .pagination>.disabled>a:focus, .pagination>.disabled>a:hover, .pagination>.disabled>span, .pagination>.disabled>span:focus, .pagination>.disabled>span:hover {
+  background-color: var(--color-background-subnav);
+  border-color: var(--color-background-subnav);
+}
+
+.breadcrumb>li, .pagination {
+  display: inline;
+}
+
+.tabGroup a[role="tab"] {
+  border-bottom: 2px solid var(--color-background-dark);
+}
+
+.tabGroup a[role="tab"][aria-selected="true"] {
+  color: var(--color-foreground);
+}
+
+.tabGroup section[role="tabpanel"] {
+  border: 1px solid var(--color-background-dark);
+}
+
+.sideaffix > div.contribution > ul > li > a.contribution-link:hover {
+  background-color: var(--color-background);
+}
+
+.switch {
+  position: relative;
+  display: inline-block;
+  width: 40px;
+  height: 20px;
+}
+
+.switch input { 
+  opacity: 0;
+  width: 0;
+  height: 0;
+}
+
+.slider {
+  position: absolute;
+  cursor: pointer;
+  top: 0;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  background-color: #ccc;
+  -webkit-transition: .4s;
+  transition: .4s;
+}
+
+.slider:before {
+  position: absolute;
+  content: "";
+  height: 14px;
+  width: 14px;
+  left: 4px;
+  bottom: 3px;
+  background-color: white;
+  -webkit-transition: .4s;
+  transition: .4s;
+}
+
+input:checked + .slider {
+  background-color: #337ab7;
+}
+
+input:focus + .slider {
+  box-shadow: 0 0 1px #337ab7;
+}
+
+input:checked + .slider:before {
+  -webkit-transform: translateX(19px);
+  -ms-transform: translateX(19px);
+  transform: translateX(19px);
+}
+
+/* Rounded sliders */
+.slider.round {
+  border-radius: 20px;
+}
+
+.slider.round:before {
+  border-radius: 50%;
+}
+.toggle-mode .icon {
+  display: inline-block;
+}
+
+.toggle-mode .icon i {
+  font-style: normal;
+  font-size: 17px;
+  display: inline-block;
+  padding-right: 7px;
+  padding-left: 7px;
+  vertical-align: middle;
+}
+
+@media (min-width: 1600px) {
+  .container {
+    width: 100%;
+  }
+  .sidefilter {
+    width: 18%;
+  }
+  .sidetoc {
+    width: 18%;
+  }
+  .article.grid-right {
+    margin-left: 19%;
+  }
+  .sideaffix {
+    width: 11.5%;
+  }
+  .affix ul>li.active>a {
+    white-space: initial;
+  }
+  .affix ul>li>a {
+    width: 99%;
+    overflow: hidden;
+    white-space: nowrap;
+    text-overflow: ellipsis;
+  }
+}

Robust.Docfx/templates/darkfx/styles/toggle-theme.js

@@ -0,0 +1,35 @@
+const sw = document.getElementById("switch-style"), sw_mobile = document.getElementById("switch-style-m"), b = document.body;
+if (b) {
+  function toggleTheme(target, dark) {
+    target.classList.toggle("dark-theme", dark)
+    target.classList.toggle("light-theme", !dark)
+  }
+
+  function switchEventListener() {
+    toggleTheme(b, this.checked);
+    if (window.localStorage) {
+      this.checked ? localStorage.setItem("theme", "dark-theme") : localStorage.setItem("theme", "light-theme")
+    }
+  }
+
+  var isDarkTheme = !window.localStorage || !window.localStorage.getItem("theme") || window.localStorage && localStorage.getItem("theme") === "dark-theme";
+
+  if(sw && sw_mobile){
+    sw.checked = isDarkTheme;
+    sw_mobile.checked = isDarkTheme;
+
+    sw.addEventListener("change", switchEventListener);
+    sw_mobile.addEventListener("change", switchEventListener);
+    
+    // sync state between switches
+    sw.addEventListener("change", function() {
+      sw_mobile.checked = this.checked;
+    });
+
+    sw_mobile.addEventListener("change", function() {
+      sw.checked = this.checked;
+    });
+  }
+
+  toggleTheme(b, isDarkTheme);
+}

Robust.Docfx/toc.yml

@@ -0,0 +1,29 @@
+- name: Articles
+  href: articles/
+  
+# Client 
+- name: Robust.Client 
+  href: api/Robust.Client/
+  homepage: api/Robust.Client/Robust.Client.html
+- name: Robust.Client.WebView
+  href: api/Robust.Client.WebView/
+
+#Loader Api
+- name: Robust.LoaderApi
+  href: api/Robust.LoaderApi/Robust.LoaderApi/
+  
+# Server
+- name: Robust.Server
+  href: api/Robust.Server/
+
+# Shared 
+- name: Robust.Shared
+  href: api/Robust.Shared/
+- name: Robust.Shared.Maths
+  href: api/Robust.Shared.Maths/
+- name: Robust.Shared.Scripting
+  href: api/Robust.Shared.Scripting/
+
+# Unit testing
+- name: Robust.UnitTesting
+  href: api/Robust.UnitTesting/

Robust.Server/BaseServer.cs

@@ -66,18 +66,17 @@ namespace Robust.Server
 
         [Dependency] private readonly IConfigurationManagerInternal _config = default!;
         [Dependency] private readonly IServerEntityManager _entityManager = default!;
-        [Dependency] private readonly IEntityLookup _lookup = default!;
         [Dependency] private readonly ILogManager _log = default!;
         [Dependency] private readonly IRobustSerializer _serializer = default!;
         [Dependency] private readonly IGameTiming _time = default!;
         [Dependency] private readonly IResourceManagerInternal _resources = default!;
         [Dependency] private readonly IMapManager _mapManager = default!;
-        [Dependency] private readonly ITimerManager timerManager = default!;
+        [Dependency] private readonly ITimerManager _timerManager = default!;
         [Dependency] private readonly IServerGameStateManager _stateManager = default!;
         [Dependency] private readonly IServerNetManager _network = default!;
         [Dependency] private readonly ISystemConsoleManager _systemConsole = default!;
         [Dependency] private readonly ITaskManager _taskManager = default!;
-        [Dependency] private readonly IRuntimeLog runtimeLog = default!;
+        [Dependency] private readonly IRuntimeLog _runtimeLog = default!;
         [Dependency] private readonly IModLoaderInternal _modLoader = default!;
         [Dependency] private readonly IWatchdogApi _watchdogApi = default!;
         [Dependency] private readonly HubManager _hubManager = default!;
@@ -127,7 +126,7 @@ namespace Robust.Server
             else
                 Logger.InfoS("srv", $"{reason}, shutting down...");
 
-            _shutdownReason = reason;
+            _shutdownReason = reason ?? "Shutting down";
 
             if (_mainLoop != null) _mainLoop.Running = false;
             if (_logHandler != null)
@@ -344,7 +343,6 @@ namespace Robust.Server
             _consoleHost.Initialize();
             _entityManager.Startup();
             _mapManager.Startup();
-            IoCManager.Resolve<IEntityLookup>().Startup();
             _stateManager.Initialize();
 
             var reg = _entityManager.ComponentFactory.GetRegistration<TransformComponent>();
@@ -603,7 +601,6 @@ namespace Robust.Server
             _network.Shutdown($"Server shutting down: {_shutdownReason}");
 
             // shutdown entities
-            IoCManager.Resolve<IEntityLookup>().Shutdown();
             _entityManager.Cleanup();
 
             if (_config.GetCVar(CVars.LogRuntimeLog))
@@ -614,7 +611,7 @@ namespace Robust.Server
                 Directory.CreateDirectory(relPath);
                 var pathToWrite = Path.Combine(relPath,
                     "Runtime-" + DateTime.Now.ToString("yyyy-MM-dd-THH-mm-ss") + ".txt");
-                File.WriteAllText(pathToWrite, runtimeLog.Display(), EncodingHelpers.UTF8);
+                File.WriteAllText(pathToWrite, _runtimeLog.Display(), EncodingHelpers.UTF8);
             }
 
             AppDomain.CurrentDomain.ProcessExit -= ProcessExiting;
@@ -659,7 +656,8 @@ namespace Robust.Server
 
             using (TickUsage.WithLabels("Timers").NewTimer())
             {
-                timerManager.UpdateTimers(frameEventArgs);
+                _consoleHost.CommandBufferExecute();
+                _timerManager.UpdateTimers(frameEventArgs);
             }
 
             using (TickUsage.WithLabels("AsyncTasks").NewTimer())
@@ -670,8 +668,6 @@ namespace Robust.Server
             // Pass Histogram into the IEntityManager.Update so it can do more granular measuring.
             _entityManager.TickUpdate(frameEventArgs.DeltaSeconds, noPredictions: false, TickUsage);
 
-            _lookup.Update();
-
             using (TickUsage.WithLabels("PostEngine").NewTimer())
             {
                 _modLoader.BroadcastUpdate(ModUpdateLevel.PostEngine, frameEventArgs);

Robust.Server/Bql/BqlQuerySelector.Builtin.cs

@@ -311,7 +311,7 @@ namespace Robust.Server.Bql
         public override IEnumerable<EntityUid> DoSelection(IEnumerable<EntityUid> input, IReadOnlyList<object> arguments, bool isInverted, IEntityManager entityManager)
         {
             var radius = (float)(double)arguments[0];
-            var entityLookup = IoCManager.Resolve<IEntityLookup>();
+            var entityLookup = EntitySystem.Get<EntityLookupSystem>();
 
             // TODO: Make this a foreach and reduce LINQ chain because it'll allocate a LOT
             //BUG: GetEntitiesInRange effectively uses manhattan distance. This is not intended, near is supposed to be circular.

Robust.Server/Console/Commands/MapCommands.cs

@@ -29,14 +29,13 @@ namespace Robust.Server.Console.Commands
             var mapId = new MapId(int.Parse(args[0]));
 
             var mapMgr = IoCManager.Resolve<IMapManager>();
-            var pauseMgr = IoCManager.Resolve<IPauseManager>();
 
             if (!mapMgr.MapExists(mapId))
             {
                 mapMgr.CreateMap(mapId);
                 if (args.Length >= 2 && args[1] == "false")
                 {
-                    pauseMgr.AddUninitializedMap(mapId);
+                    mapMgr.AddUninitializedMap(mapId);
                 }
 
                 shell.WriteLine($"Map with ID {mapId} created.");
@@ -219,7 +218,11 @@ namespace Robust.Server.Console.Commands
             }
 
             IoCManager.Resolve<IMapLoader>().LoadMap(mapId, args[1]);
-            shell.WriteLine($"Map {mapId} has been loaded from {args[1]}.");
+
+            if (mapManager.MapExists(mapId))
+                shell.WriteLine($"Map {mapId} has been loaded from {args[1]}.");
+            else
+                shell.WriteError($"Error while loading map from {args[1]}.");
         }
     }
 
@@ -318,7 +321,6 @@ namespace Robust.Server.Console.Commands
             }
 
             var mapManager = IoCManager.Resolve<IMapManager>();
-            var pauseManager = IoCManager.Resolve<IPauseManager>();
 
             var arg = args[0];
             var mapId = new MapId(int.Parse(arg, CultureInfo.InvariantCulture));
@@ -329,13 +331,13 @@ namespace Robust.Server.Console.Commands
                 return;
             }
 
-            if (pauseManager.IsMapInitialized(mapId))
+            if (mapManager.IsMapInitialized(mapId))
             {
                 shell.WriteError("Map is already initialized!");
                 return;
             }
 
-            pauseManager.DoMapInitialize(mapId);
+            mapManager.DoMapInitialize(mapId);
         }
     }
 
@@ -348,17 +350,16 @@ namespace Robust.Server.Console.Commands
         public void Execute(IConsoleShell shell, string argStr, string[] args)
         {
             var mapManager = IoCManager.Resolve<IMapManager>();
-            var pauseManager = IoCManager.Resolve<IPauseManager>();
 
             var msg = new StringBuilder();
 
             foreach (var mapId in mapManager.GetAllMapIds().OrderBy(id => id.Value))
             {
                 msg.AppendFormat("{0}: init: {1}, paused: {2}, ent: {3}, grids: {4}\n",
-                    mapId, pauseManager.IsMapInitialized(mapId),
-                    pauseManager.IsMapPaused(mapId),
-                    string.Join(",", mapManager.GetAllMapGrids(mapId).Select(grid => grid.Index)),
-                    mapManager.GetMapEntityId(mapId));
+                    mapId, mapManager.IsMapInitialized(mapId),
+                    mapManager.IsMapPaused(mapId),
+                    mapManager.GetMapEntityId(mapId),
+                    string.Join(",", mapManager.GetAllMapGrids(mapId).Select(grid => grid.Index)));
             }
 
             shell.WriteLine(msg.ToString());
@@ -380,7 +381,7 @@ namespace Robust.Server.Console.Commands
             foreach (var grid in mapManager.GetAllGrids().OrderBy(grid => grid.Index.Value))
             {
                 msg.AppendFormat("{0}: map: {1}, ent: {2}, pos: {3} \n",
-                    grid.Index, grid.ParentMapId, grid.WorldPosition, grid.GridEntityId);
+                    grid.Index, grid.ParentMapId, grid.GridEntityId, grid.WorldPosition);
             }
 
             shell.WriteLine(msg.ToString());

Robust.Server/Console/Commands/TestbedCommand.cs

@@ -109,9 +109,8 @@ namespace Robust.Server.Console.Commands
         private void SetupPlayer(MapId mapId, IConsoleShell shell, IPlayerSession? player, IMapManager mapManager)
         {
             if (mapId == MapId.Nullspace) return;
-            var pauseManager = IoCManager.Resolve<IPauseManager>();
-            pauseManager.SetMapPaused(mapId, false);
-            var mapUid = IoCManager.Resolve<IMapManager>().GetMapEntityIdOrThrow(mapId);
+            mapManager.SetMapPaused(mapId, false);
+            var mapUid = mapManager.GetMapEntityIdOrThrow(mapId);
             IoCManager.Resolve<IEntityManager>().GetComponent<SharedPhysicsMapComponent>(mapUid).Gravity = new Vector2(0, -9.8f);
 
             return;

Robust.Server/GameObjects/EntitySystems/AppearanceSystem.cs

@@ -3,7 +3,7 @@ using Robust.Shared.GameStates;
 
 namespace Robust.Server.GameObjects;
 
-internal sealed class AppearanceSystem : SharedAppearanceSystem
+public sealed class AppearanceSystem : SharedAppearanceSystem
 {
     public override void Initialize()
     {

Robust.Server/GameObjects/EntitySystems/PhysicsSystem.cs

@@ -1,4 +1,4 @@
-using JetBrains.Annotations;
+using JetBrains.Annotations;
 using Robust.Server.Physics;
 using Robust.Shared;
 using Robust.Shared.Configuration;
@@ -37,7 +37,7 @@ namespace Robust.Server.GameObjects
             collideComp.BodyType = BodyType.Static;
         }
 
-        protected override void HandleMapCreated(object? sender, MapEventArgs eventArgs)
+        protected override void HandleMapCreated(MapChangedEvent eventArgs)
         {
             if (eventArgs.Map == MapId.Nullspace) return;
             var mapUid = MapManager.GetMapEntityIdOrThrow(eventArgs.Map);

Robust.Server/GameStates/ChunkIndicesEnumerator.cs

@@ -5,30 +5,31 @@ namespace Robust.Server.GameStates;
 
 public struct ChunkIndicesEnumerator
 {
-    private Vector2i _topLeft;
-    private Vector2i _bottomRight;
+    private Vector2i _bottomLeft;
+    private Vector2i _topRight;
 
     private int _x;
     private int _y;
 
-    public ChunkIndicesEnumerator(Box2 viewBox, float chunkSize)
+    public ChunkIndicesEnumerator(Vector2 viewPos, float range, float chunkSize)
     {
-        _topLeft = (viewBox.TopLeft / chunkSize).Floored();
-        _bottomRight = (viewBox.BottomRight / chunkSize).Floored();
+        _bottomLeft = ((viewPos - range) / chunkSize).Floored();
+        // Also floor this as we get the whole chunk anyway.
+        _topRight = ((viewPos + range) / chunkSize).Floored();
 
-        _x = _topLeft.X;
-        _y = _bottomRight.Y;
+        _x = _bottomLeft.X;
+        _y = _bottomLeft.Y;
     }
 
     public bool MoveNext([NotNullWhen(true)] out Vector2i? chunkIndices)
     {
-        if (_y > _topLeft.Y)
+        if (_y > _topRight.Y)
         {
             _x++;
-            _y = _bottomRight.Y;
+            _y = _bottomLeft.Y;
         }
 
-        if (_x > _bottomRight.X)
+        if (_x > _topRight.X)
         {
             chunkIndices = null;
             return false;

Robust.Server/GameStates/PVSCollection.cs

@@ -37,7 +37,6 @@ public interface IPVSCollection
 public sealed class PVSCollection<TIndex> : IPVSCollection where TIndex : IComparable<TIndex>, IEquatable<TIndex>
 {
     [Shared.IoC.Dependency] private readonly IEntityManager _entityManager = default!;
-    [Shared.IoC.Dependency] private readonly IMapManager _mapManager = default!;
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     private static Vector2i GetChunkIndices(Vector2 coordinates)
@@ -81,19 +80,24 @@ public sealed class PVSCollection<TIndex> : IPVSCollection where TIndex : ICompa
     private readonly List<(GameTick tick, TIndex index)> _deletionHistory = new();
 
     /// <summary>
-    /// An index containing the <see cref="IndexLocation"/>s of all <see cref="TIndex"/>.
+    /// An index containing the <see cref="IIndexLocation"/>s of all <see cref="TIndex"/>.
     /// </summary>
-    private readonly Dictionary<TIndex, IndexLocation> _indexLocations = new();
+    private readonly Dictionary<TIndex, IIndexLocation> _indexLocations = new();
 
     /// <summary>
     /// Buffer of all locationchanges since the last process call
     /// </summary>
-    private readonly Dictionary<TIndex, IndexLocation> _locationChangeBuffer = new();
+    private readonly Dictionary<TIndex, IIndexLocation> _locationChangeBuffer = new();
     /// <summary>
     /// Buffer of all indexremovals since the last process call
     /// </summary>
     private readonly Dictionary<TIndex, GameTick> _removalBuffer = new();
 
+    /// <summary>
+    /// To avoid re-allocating the hashset every tick we'll just store it.
+    /// </summary>
+    private HashSet<TIndex> _changedIndices = new();
+
     public PVSCollection()
     {
         IoCManager.InjectDependencies(this);
@@ -101,13 +105,18 @@ public sealed class PVSCollection<TIndex> : IPVSCollection where TIndex : ICompa
 
     public void Process()
     {
-        var changedIndices = new HashSet<TIndex>(_locationChangeBuffer.Keys);
+        _changedIndices.EnsureCapacity(_locationChangeBuffer.Count);
 
-        var changedChunkLocations = new HashSet<IndexLocation>();
+        foreach (var (key, _) in _locationChangeBuffer)
+        {
+            _changedIndices.Add(key);
+        }
+
+        var changedChunkLocations = new HashSet<IIndexLocation>();
         foreach (var (index, tick) in _removalBuffer)
         {
             //changes dont need to be computed if we are removing the index anyways
-            if (changedIndices.Remove(index) && !_indexLocations.ContainsKey(index))
+            if (_changedIndices.Remove(index) && !_indexLocations.ContainsKey(index))
             {
                 //this index wasnt added yet, so we can safely just skip the deletion
                 continue;
@@ -135,13 +144,14 @@ public sealed class PVSCollection<TIndex> : IPVSCollection where TIndex : ICompa
             }
         }
 
-        foreach (var index in changedIndices)
+        foreach (var index in _changedIndices)
         {
             RemoveIndexInternal(index);
 
             AddIndexInternal(index, _locationChangeBuffer[index]);
         }
 
+        _changedIndices.Clear();
         _locationChangeBuffer.Clear();
         _removalBuffer.Clear();
     }
@@ -154,7 +164,7 @@ public sealed class PVSCollection<TIndex> : IPVSCollection where TIndex : ICompa
 
     public HashSet<TIndex>.Enumerator GetElementsForSession(ICommonSession session) => _localOverrides[session].GetEnumerator();
 
-    private void AddIndexInternal(TIndex index, IndexLocation location)
+    private void AddIndexInternal(TIndex index, IIndexLocation location)
     {
         switch (location)
         {
@@ -186,7 +196,7 @@ public sealed class PVSCollection<TIndex> : IPVSCollection where TIndex : ICompa
         _indexLocations.Add(index, location);
     }
 
-    private IndexLocation? RemoveIndexInternal(TIndex index)
+    private IIndexLocation? RemoveIndexInternal(TIndex index)
     {
         // the index might be gone due to disconnects/grid-/map-deletions
         if (!_indexLocations.TryGetValue(index, out var location))
@@ -321,6 +331,9 @@ public sealed class PVSCollection<TIndex> : IPVSCollection where TIndex : ICompa
         if(!removeFromOverride && IsOverride(index))
             return;
 
+        if (_indexLocations.TryGetValue(index, out var oldLocation) &&
+            oldLocation is GlobalOverride) return;
+
         RegisterUpdate(index, new GlobalOverride());
     }
 
@@ -335,6 +348,10 @@ public sealed class PVSCollection<TIndex> : IPVSCollection where TIndex : ICompa
         if(!removeFromOverride && IsOverride(index))
             return;
 
+        if (_indexLocations.TryGetValue(index, out var oldLocation) &&
+            oldLocation is LocalOverride local &&
+            local.Session == session) return;
+
         RegisterUpdate(index, new LocalOverride(session));
     }
 
@@ -352,14 +369,14 @@ public sealed class PVSCollection<TIndex> : IPVSCollection where TIndex : ICompa
         var gridId = coordinates.GetGridId(_entityManager);
         if (gridId != GridId.Invalid)
         {
-            var gridIndices = GetChunkIndices(_mapManager.GetGrid(gridId).LocalToGrid(coordinates));
+            var gridIndices = GetChunkIndices(coordinates.Position);
             UpdateIndex(index, gridId, gridIndices, true); //skip overridecheck bc we already did it (saves some dict lookups)
             return;
         }
 
-        var mapId = coordinates.GetMapId(_entityManager);
-        var mapIndices = GetChunkIndices(coordinates.ToMapPos(_entityManager));
-        UpdateIndex(index, mapId, mapIndices, true); //skip overridecheck bc we already did it (saves some dict lookups)
+        var mapCoordinates = coordinates.ToMap(_entityManager);
+        var mapIndices = GetChunkIndices(coordinates.Position);
+        UpdateIndex(index, mapCoordinates.MapId, mapIndices, true); //skip overridecheck bc we already did it (saves some dict lookups)
     }
 
     /// <summary>
@@ -374,6 +391,11 @@ public sealed class PVSCollection<TIndex> : IPVSCollection where TIndex : ICompa
         if(!removeFromOverride && IsOverride(index))
             return;
 
+        if (_indexLocations.TryGetValue(index, out var oldLocation) &&
+            oldLocation is GridChunkLocation oldGrid &&
+            oldGrid.ChunkIndices == chunkIndices &&
+            oldGrid.GridId == gridId) return;
+
         RegisterUpdate(index, new GridChunkLocation(gridId, chunkIndices));
     }
 
@@ -389,25 +411,92 @@ public sealed class PVSCollection<TIndex> : IPVSCollection where TIndex : ICompa
         if(!removeFromOverride && IsOverride(index))
             return;
 
+        if (_indexLocations.TryGetValue(index, out var oldLocation) &&
+            oldLocation is MapChunkLocation oldMap &&
+            oldMap.ChunkIndices == chunkIndices &&
+            oldMap.MapId == mapId) return;
+
         RegisterUpdate(index, new MapChunkLocation(mapId, chunkIndices));
     }
 
-    private void RegisterUpdate(TIndex index, IndexLocation location)
+    private void RegisterUpdate(TIndex index, IIndexLocation location)
     {
-        if(_indexLocations.TryGetValue(index, out var oldLocation) && oldLocation == location) return;
-
         _locationChangeBuffer[index] = location;
     }
 
     #endregion
-
-    #region IndexLocations
-
-    private abstract record IndexLocation;
-    private record MapChunkLocation(MapId MapId, Vector2i ChunkIndices) : IndexLocation;
-    private record GridChunkLocation(GridId GridId, Vector2i ChunkIndices) : IndexLocation;
-    private record GlobalOverride : IndexLocation;
-    private record LocalOverride(ICommonSession Session) : IndexLocation;
-
-    #endregion
 }
+
+#region IndexLocations
+
+public interface IIndexLocation {};
+
+public interface IChunkIndexLocation{ };
+
+public struct MapChunkLocation : IIndexLocation, IChunkIndexLocation, IEquatable<MapChunkLocation>
+{
+    public MapChunkLocation(MapId mapId, Vector2i chunkIndices)
+    {
+        MapId = mapId;
+        ChunkIndices = chunkIndices;
+    }
+
+    public MapId MapId { get; init; }
+    public Vector2i ChunkIndices { get; init; }
+
+    public bool Equals(MapChunkLocation other)
+    {
+        return MapId.Equals(other.MapId) && ChunkIndices.Equals(other.ChunkIndices);
+    }
+
+    public override bool Equals(object? obj)
+    {
+        return obj is MapChunkLocation other && Equals(other);
+    }
+
+    public override int GetHashCode()
+    {
+        return HashCode.Combine(MapId, ChunkIndices);
+    }
+}
+
+public struct GridChunkLocation : IIndexLocation, IChunkIndexLocation, IEquatable<GridChunkLocation>
+{
+    public GridChunkLocation(GridId gridId, Vector2i chunkIndices)
+    {
+        GridId = gridId;
+        ChunkIndices = chunkIndices;
+    }
+
+    public GridId GridId { get; init; }
+    public Vector2i ChunkIndices { get; init; }
+
+    public bool Equals(GridChunkLocation other)
+    {
+        return GridId.Equals(other.GridId) && ChunkIndices.Equals(other.ChunkIndices);
+    }
+
+    public override bool Equals(object? obj)
+    {
+        return obj is GridChunkLocation other && Equals(other);
+    }
+
+    public override int GetHashCode()
+    {
+        return HashCode.Combine(GridId, ChunkIndices);
+    }
+}
+
+public struct GlobalOverride : IIndexLocation { }
+
+public struct LocalOverride : IIndexLocation
+{
+    public LocalOverride(ICommonSession session)
+    {
+        Session = session;
+    }
+
+    public ICommonSession Session { get; init; }
+}
+
+#endregion

Robust.Server/GameStates/RobustTree.cs

@@ -0,0 +1,174 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using Microsoft.Extensions.ObjectPool;
+
+namespace Robust.Server.GameStates;
+
+public sealed class RobustTree<T> where T : notnull
+{
+    private Dictionary<T, TreeNode> _nodeIndex = new();
+
+    private Dictionary<T, T> _parents = new();
+    public readonly HashSet<T> RootNodes = new();
+
+    private ObjectPool<HashSet<T>> _pool;
+
+    public RobustTree(ObjectPool<HashSet<T>>? pool = null)
+    {
+        _pool = pool ?? new DefaultObjectPool<HashSet<T>>(new PVSSystem.SetPolicy<T>());
+    }
+
+    public void Clear()
+    {
+        foreach (var value in _nodeIndex.Values)
+        {
+            if(value.Children != null)
+                _pool.Return(value.Children);
+        }
+        _nodeIndex.Clear();
+        _parents.Clear();
+        RootNodes.Clear();
+    }
+
+    public TreeNode this[T index] => _nodeIndex[index];
+
+    public void Remove(T value, bool mend = false)
+    {
+        if (!_nodeIndex.TryGetValue(value, out var node))
+            throw new InvalidOperationException("Node doesnt exist.");
+
+
+        if (RootNodes.Contains(value))
+        {
+            if (node.Children != null)
+            {
+                foreach (var child in node.Children)
+                {
+                    _parents.Remove(child);
+                    RootNodes.Add(child);
+                }
+                _pool.Return(node.Children);
+            }
+            RootNodes.Remove(value);
+            _nodeIndex.Remove(value);
+            return;
+        }
+
+        if (_parents.TryGetValue(value, out var parent))
+        {
+            if (node.Children != null)
+            {
+                foreach (var child in node.Children)
+                {
+                    if (mend)
+                    {
+                        _parents[child] = parent;
+                        var children = _nodeIndex[parent].Children;
+                        if (children == null)
+                        {
+                            children = _pool.Get();
+                            _nodeIndex[parent] = _nodeIndex[parent].WithChildren(children);
+                        }
+                        children.Add(child);
+                    }
+                    else
+                    {
+                        _parents.Remove(child);
+                        RootNodes.Add(child);
+                    }
+                }
+
+                _pool.Return(node.Children);
+            }
+            _parents.Remove(value);
+            _nodeIndex.Remove(value);
+        }
+
+        throw new InvalidOperationException("Node neither had a parent nor was a RootNode.");
+    }
+
+    public TreeNode Set(T rootNode)
+    {
+        //root node, for now
+        if (_nodeIndex.TryGetValue(rootNode, out var node))
+        {
+            if(!RootNodes.Contains(rootNode))
+                throw new InvalidOperationException("Node already exists as non-root node.");
+            return node;
+        }
+
+        node = new TreeNode(rootNode);
+        _nodeIndex.Add(rootNode, node);
+        RootNodes.Add(rootNode);
+        return node;
+    }
+
+    public TreeNode Set(T child, T parent)
+    {
+        if (!_nodeIndex.TryGetValue(parent, out var parentNode))
+            parentNode = Set(parent);
+
+        if (parentNode.Children == null)
+        {
+            _nodeIndex[parent] = parentNode = parentNode.WithChildren(_pool.Get());
+        }
+
+        if (_nodeIndex.TryGetValue(child, out var existingNode))
+        {
+            if (RootNodes.Contains(child))
+            {
+                parentNode.Children!.Add(existingNode.Value);
+                RootNodes.Remove(child);
+                _parents.Add(child, parent);
+                return existingNode;
+            }
+
+            if (!_parents.TryGetValue(child, out var previousParent) || _nodeIndex.TryGetValue(previousParent, out var previousParentNode))
+                throw new InvalidOperationException("Could not find old parent for non-root node.");
+
+            previousParentNode.Children?.Remove(existingNode.Value);
+            parentNode.Children!.Add(existingNode.Value);
+            _parents[child] = parent;
+            return existingNode;
+        }
+
+        existingNode = new TreeNode(child);
+        _nodeIndex.Add(child, existingNode);
+        parentNode.Children!.Add(existingNode.Value);
+        _parents.Add(child, parent);
+        return existingNode;
+    }
+
+    public readonly struct TreeNode : IEquatable<TreeNode>
+    {
+        public readonly T Value;
+        public readonly HashSet<T>? Children;
+
+        public TreeNode(T value, HashSet<T>? children = null)
+        {
+            Value = value;
+            Children = children;
+        }
+
+        public bool Equals(TreeNode other)
+        {
+            return Value.Equals(other.Value) && Children?.Equals(other.Children) == true;
+        }
+
+        public override bool Equals(object? obj)
+        {
+            return obj is TreeNode other && Equals(other);
+        }
+
+        public override int GetHashCode()
+        {
+            return HashCode.Combine(Value, Children);
+        }
+
+        public TreeNode WithChildren(HashSet<T> children)
+        {
+            return new TreeNode(Value, children);
+        }
+    }
+}

Robust.Server/GameStates/ServerGameStateManager.cs

@@ -1,9 +1,12 @@
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using JetBrains.Annotations;
+using Microsoft.CodeAnalysis;
+using Microsoft.Extensions.ObjectPool;
 using Robust.Server.GameObjects;
 using Robust.Server.Player;
 using Robust.Shared.Enums;
@@ -125,6 +128,37 @@ namespace Robust.Server.GameStates
             // people not in the game don't get states
             var players = _playerManager.ServerSessions.Where(o => o.Status == SessionStatus.InGame).ToArray();
 
+            //todo paul oh my god make this less shit
+            EntityQuery<MetaDataComponent> metadataQuery = default!;
+            EntityQuery<TransformComponent> transformQuery = default!;
+            HashSet<int>[] playerChunks = default!;
+            EntityUid[][] viewerEntities = default!;
+            (Dictionary<EntityUid, MetaDataComponent> metadata, RobustTree<EntityUid> tree)?[] chunkCache = default!;
+
+            if (_pvs.CullingEnabled)
+            {
+                List<(uint, IChunkIndexLocation)> chunks;
+                (chunks, playerChunks, viewerEntities) = _pvs.GetChunks(players);
+                const int ChunkBatchSize = 2;
+                var chunksCount = chunks.Count;
+                var chunkBatches = (int) MathF.Ceiling((float) chunksCount / ChunkBatchSize);
+                chunkCache =
+                    new (Dictionary<EntityUid, MetaDataComponent> metadata, RobustTree<EntityUid> tree)?[chunksCount];
+                transformQuery = _entityManager.GetEntityQuery<TransformComponent>();
+                metadataQuery = _entityManager.GetEntityQuery<MetaDataComponent>();
+                Parallel.For(0, chunkBatches, i =>
+                {
+                    var start = i * ChunkBatchSize;
+                    var end = Math.Min(start + ChunkBatchSize, chunksCount);
+
+                    for (var j = start; j < end; ++j)
+                    {
+                        var (visMask, chunkIndexLocation) = chunks[j];
+                        chunkCache[j] = _pvs.CalculateChunk(chunkIndexLocation, visMask, transformQuery, metadataQuery);
+                    }
+                });
+            }
+
             const int BatchSize = 2;
             var batches = (int) MathF.Ceiling((float) players.Length / BatchSize);
 
@@ -135,11 +169,9 @@ namespace Robust.Server.GameStates
 
                 for (var j = start; j < end; ++j)
                 {
-                    var session = players[j];
-
                     try
                     {
-                        SendStateUpdate(session);
+                        SendStateUpdate(j);
                     }
                     catch (Exception e) // Catch EVERY exception
                     {
@@ -148,8 +180,10 @@ namespace Robust.Server.GameStates
                 }
             });
 
-            void SendStateUpdate(IPlayerSession session)
+            void SendStateUpdate(int sessionIndex)
             {
+                var session = players[sessionIndex];
+
                 // KILL IT WITH FIRE
                 if(mainThread != Thread.CurrentThread)
                     IoCManager.InitThread(new DependencyCollection(parentDeps), true);
@@ -161,7 +195,10 @@ namespace Robust.Server.GameStates
                     DebugTools.Assert("Why does this channel not have an entry?");
                 }
 
-                var (entStates, deletions) = _pvs.CalculateEntityStates(session, lastAck, _gameTiming.CurTick);
+                var (entStates, deletions) = _pvs.CullingEnabled
+                    ? _pvs.CalculateEntityStates(session, lastAck, _gameTiming.CurTick, chunkCache,
+                        playerChunks[sessionIndex], metadataQuery, transformQuery, viewerEntities[sessionIndex])
+                    : _pvs.GetAllEntityStates(session, lastAck, _gameTiming.CurTick);
                 var playerStates = _playerManager.GetPlayerStates(lastAck);
                 var mapData = _mapManager.GetStateData(lastAck);
 
@@ -172,8 +209,6 @@ namespace Robust.Server.GameStates
 
                 InterlockedHelper.Min(ref oldestAckValue, lastAck.Value);
 
-                DebugTools.Assert(state.MapData?.CreatedMaps is null || (state.MapData?.CreatedMaps is not null && state.EntityStates.HasContents), "Sending new maps, but no entity state.");
-
                 // actually send the state
                 var stateUpdateMessage = _networkManager.CreateNetMessage<MsgState>();
                 stateUpdateMessage.State = state;
@@ -194,6 +229,8 @@ namespace Robust.Server.GameStates
                 _networkManager.ServerSendMessage(stateUpdateMessage, channel);
             }
 
+            if(_pvs.CullingEnabled)
+                _pvs.ReturnToPool(chunkCache, playerChunks);
             _pvs.Cleanup(_playerManager.ServerSessions);
             var oldestAck = new GameTick(oldestAckValue);
 

Robust.Server/Maps/MapLoader.cs

@@ -24,7 +24,6 @@ using Robust.Shared.Serialization.Markdown.Mapping;
 using Robust.Shared.Serialization.Markdown.Validation;
 using Robust.Shared.Serialization.Markdown.Value;
 using Robust.Shared.Serialization.TypeSerializers.Interfaces;
-using Robust.Shared.Timing;
 using Robust.Shared.Utility;
 using YamlDotNet.Core;
 using YamlDotNet.RepresentationModel;
@@ -44,7 +43,6 @@ namespace Robust.Server.Maps
         [Dependency] private readonly IMapManagerInternal _mapManager = default!;
         [Dependency] private readonly ITileDefinitionManager _tileDefinitionManager = default!;
         [Dependency] private readonly IServerEntityManagerInternal _serverEntityManager = default!;
-        [Dependency] private readonly IPauseManager _pauseManager = default!;
         [Dependency] private readonly IPrototypeManager _prototypeManager = default!;
 
         public event Action<YamlStream, string>? LoadedMapData;
@@ -54,7 +52,7 @@ namespace Robust.Server.Maps
         {
             var grid = _mapManager.GetGrid(gridId);
 
-            var context = new MapContext(_mapManager, _tileDefinitionManager, _serverEntityManager, _pauseManager, _prototypeManager);
+            var context = new MapContext(_mapManager, _tileDefinitionManager, _serverEntityManager, _prototypeManager);
             context.RegisterGrid(grid);
             var root = context.Serialize();
             var document = new YamlDocument(root);
@@ -100,7 +98,7 @@ namespace Robust.Server.Maps
                     throw new InvalidDataException("Cannot instance map with multiple grids as blueprint.");
                 }
 
-                var context = new MapContext(_mapManager, _tileDefinitionManager, _serverEntityManager, _pauseManager,
+                var context = new MapContext(_mapManager, _tileDefinitionManager, _serverEntityManager,
                     _prototypeManager, (YamlMappingNode) data.RootNode, mapId, options);
                 context.Deserialize();
                 grid = context.Grids[0];
@@ -120,7 +118,7 @@ namespace Robust.Server.Maps
                     _serverEntityManager.GetComponent<MetaDataComponent>(entity).EntityLifeStage = EntityLifeStage.MapInitialized;
                 }
             }
-            else if (_pauseManager.IsMapInitialized(mapId))
+            else if (_mapManager.IsMapInitialized(mapId))
             {
                 foreach (var entity in context.Entities)
                 {
@@ -128,7 +126,7 @@ namespace Robust.Server.Maps
                 }
             }
 
-            if (_pauseManager.IsMapPaused(mapId))
+            if (_mapManager.IsMapPaused(mapId))
             {
                 foreach (var entity in context.Entities)
                 {
@@ -141,7 +139,7 @@ namespace Robust.Server.Maps
         public void SaveMap(MapId mapId, string yamlPath)
         {
             Logger.InfoS("map", $"Saving map {mapId} to {yamlPath}");
-            var context = new MapContext(_mapManager, _tileDefinitionManager, _serverEntityManager, _pauseManager, _prototypeManager);
+            var context = new MapContext(_mapManager, _tileDefinitionManager, _serverEntityManager, _prototypeManager);
             foreach (var grid in _mapManager.GetAllMapGrids(mapId))
             {
                 context.RegisterGrid(grid);
@@ -207,7 +205,7 @@ namespace Robust.Server.Maps
 
                 LoadedMapData?.Invoke(data.Stream, resPath.ToString());
 
-                var context = new MapContext(_mapManager, _tileDefinitionManager, _serverEntityManager, _pauseManager,
+                var context = new MapContext(_mapManager, _tileDefinitionManager, _serverEntityManager,
                     _prototypeManager, (YamlMappingNode) data.RootNode, mapId, options);
                 context.Deserialize();
 
@@ -226,12 +224,12 @@ namespace Robust.Server.Maps
             private readonly IMapManagerInternal _mapManager;
             private readonly ITileDefinitionManager _tileDefinitionManager;
             private readonly IServerEntityManagerInternal _serverEntityManager;
-            private readonly IPauseManager _pauseManager;
             private readonly IPrototypeManager _prototypeManager;
 
             private readonly MapLoadOptions? _loadOptions;
             private readonly Dictionary<GridId, int> GridIDMap = new();
             public readonly List<MapGrid> Grids = new();
+            private readonly List<GridId> _readGridIndices = new();
 
             private readonly Dictionary<EntityUid, int> EntityUidMap = new();
             private readonly Dictionary<int, EntityUid> UidEntityMap = new();
@@ -260,12 +258,11 @@ namespace Robust.Server.Maps
             public bool MapIsPostInit { get; private set; }
 
             public MapContext(IMapManagerInternal maps, ITileDefinitionManager tileDefs,
-                IServerEntityManagerInternal entities, IPauseManager pauseManager, IPrototypeManager prototypeManager)
+                IServerEntityManagerInternal entities, IPrototypeManager prototypeManager)
             {
                 _mapManager = maps;
                 _tileDefinitionManager = tileDefs;
                 _serverEntityManager = entities;
-                _pauseManager = pauseManager;
                 _prototypeManager = prototypeManager;
 
                 RootNode = new YamlMappingNode();
@@ -283,13 +280,12 @@ namespace Robust.Server.Maps
 
             public MapContext(IMapManagerInternal maps, ITileDefinitionManager tileDefs,
                 IServerEntityManagerInternal entities,
-                IPauseManager pauseManager, IPrototypeManager prototypeManager,
+                IPrototypeManager prototypeManager,
                 YamlMappingNode node, MapId targetMapId, MapLoadOptions options)
             {
                 _mapManager = maps;
                 _tileDefinitionManager = tileDefs;
                 _serverEntityManager = entities;
-                _pauseManager = pauseManager;
                 _loadOptions = options;
 
                 RootNode = node;
@@ -319,9 +315,8 @@ namespace Robust.Server.Maps
                 // Create the new map.
                 AllocMap();
 
-                // Load grids.
-                ReadTileMapSection();
-                ReadGridSection();
+                // Maps grid section indices to GridIds, for deserializing GridIds on entities.
+                ReadGridSectionIndices();
 
                 // Entities are first allocated. This allows us to know the future UID of all entities on the map before
                 // even ExposeData is loaded. This allows us to resolve serialized EntityUid instances correctly.
@@ -330,8 +325,11 @@ namespace Robust.Server.Maps
                 // Actually instance components and run ExposeData on them.
                 FinishEntitiesLoad();
 
-                // Finish binding MapGrids to their respective MapGridComponents.
-                BindGridComponents();
+                // Load grids.
+                ReadTileMapSection();
+
+                // Reads the grid section, allocates MapGrids, and maps them to their respective MapGridComponents.
+                ReadGridSection();
 
                 // Clear the net tick numbers so that components from prototypes (not modified by map)
                 // aren't sent over the wire initially.
@@ -479,18 +477,20 @@ namespace Robust.Server.Maps
                 }
             }
 
-            private void BindGridComponents()
+            private void ReadGridSection()
             {
                 // There were no new grids, nothing to do here.
-                if(Grids.Count == 0)
+                if(_readGridIndices.Count == 0)
                     return;
 
                 // MapGrids already contain their assigned GridId from their ctor, and the MapComponents just got deserialized.
                 // Now we need to actually bind the MapGrids to their components so that you can resolve GridId -> EntityUid
                 // After doing this, it should be 100% safe to use the MapManager API like normal.
 
+                var yamlGrids = RootNode.GetNode<YamlSequenceNode>("grids");
+
                 // get ents that the grids will bind to
-                var gridComps = new Dictionary<GridId, MapGridComponent>(Grids.Count);
+                var gridComps = new Dictionary<GridId, MapGridComponent>(_readGridIndices.Count);
 
                 // linear search for new grid comps
                 foreach (var tuple in _entitiesToDeserialize)
@@ -507,15 +507,54 @@ namespace Robust.Server.Maps
                     gridComps[gridComp.GridIndex] = gridComp;
                 }
 
-                // Actually bind them
-                foreach (var mapGrid in Grids)
+                for (var index = 0; index < _readGridIndices.Count; index++)
                 {
+                    // Here is where the implicit index pairing magic happens from the yaml.
+                    var gridIndex = _readGridIndices[index];
+                    var yamlGrid = (YamlMappingNode)yamlGrids.Children[index];
+
                     // designed to throw if something is broken, every grid must map to an ent
-                    var gridComp = gridComps[mapGrid.Index];
-                    _mapManager.BindGrid(gridComp, mapGrid);
+                    var gridComp = gridComps[gridIndex];
+
+                    DebugTools.Assert(gridComp.GridIndex == gridIndex);
+
+                    YamlMappingNode yamlGridInfo = (YamlMappingNode)yamlGrid["settings"];
+                    YamlSequenceNode yamlGridChunks = (YamlSequenceNode)yamlGrid["chunks"];
+
+                    var grid = AllocateMapGrid(gridComp, yamlGridInfo);
+
+                    foreach (var chunkNode in yamlGridChunks.Cast<YamlMappingNode>())
+                    {
+                        YamlGridSerializer.DeserializeChunk(_mapManager, grid, chunkNode, _tileMap!, _tileDefinitionManager);
+                    }
+
+                    Grids.Add(grid); // Grids are kept in index order
                 }
             }
 
+            private static MapGrid AllocateMapGrid(MapGridComponent gridComp, YamlMappingNode yamlGridInfo)
+            {
+                // sane defaults
+                ushort csz = 16;
+                ushort tsz = 1;
+
+                foreach (var kvInfo in yamlGridInfo)
+                {
+                    var key = kvInfo.Key.ToString();
+                    var val = kvInfo.Value.ToString();
+                    if (key == "chunksize")
+                        csz = ushort.Parse(val);
+                    else if (key == "tilesize")
+                        tsz = ushort.Parse(val);
+                    else if (key == "snapsize")
+                        continue; // obsolete
+                }
+
+                var grid = gridComp.AllocMapGrid(csz, tsz);
+
+                return grid;
+            }
+
             private void AttachMapEntities()
             {
                 var mapEntity = _mapManager.GetMapEntityIdOrThrow(TargetMap);
@@ -582,21 +621,15 @@ namespace Robust.Server.Maps
                 }
             }
 
-            private void ReadGridSection()
+            private void ReadGridSectionIndices()
             {
+                // sets up the mapping so the serializer can properly deserialize GridIds.
+
                 var yamlGrids = RootNode.GetNode<YamlSequenceNode>("grids");
 
-                foreach (var yamlGrid in yamlGrids)
+                for (var i = 0; i < yamlGrids.Children.Count; i++)
                 {
-                    var grid = YamlGridSerializer.DeserializeGrid(
-                        _mapManager, TargetMap,
-                        (YamlMappingNode) yamlGrid["settings"],
-                        (YamlSequenceNode) yamlGrid["chunks"],
-                        _tileMap!,
-                        _tileDefinitionManager
-                    );
-
-                    Grids.Add(grid);
+                    _readGridIndices.Add(_mapManager.GenerateGridId(null));
                 }
             }
 
@@ -612,7 +645,7 @@ namespace Robust.Server.Maps
 
                     if (!MapIsPostInit)
                     {
-                        _pauseManager.AddUninitializedMap(TargetMap);
+                        _mapManager.AddUninitializedMap(TargetMap);
                     }
                 }
             }
@@ -719,7 +752,7 @@ namespace Robust.Server.Maps
                 var isPostInit = false;
                 foreach (var grid in Grids)
                 {
-                    if (_pauseManager.IsMapInitialized(grid.ParentMapId))
+                    if (_mapManager.IsMapInitialized(grid.ParentMapId))
                     {
                         isPostInit = true;
                         break;
@@ -928,6 +961,13 @@ namespace Robust.Server.Maps
                 return true;
             }
 
+            [Virtual]
+            public class MapLoadException : Exception
+            {
+                public MapLoadException(string? message)
+                    : base(message) { }
+            }
+
             public DeserializationResult Read(ISerializationManager serializationManager, ValueDataNode node,
                 IDependencyCollection dependencies,
                 bool skipHook,
@@ -936,19 +976,18 @@ namespace Robust.Server.Maps
                 // This is the code that deserializes the Grids index into the GridId. This has to happen between Grid allocation
                 // and when grids are bound to their entities.
 
-                if (node.Value == "null") return new DeserializedValue<GridId>(GridId.Invalid);
+                if (node.Value == "null")
+                {
+                    throw new MapLoadException($"Error in map file: found local grid ID '{node.Value}' which does not exist.");
+                }
 
                 var val = int.Parse(node.Value);
-                if (val >= Grids.Count)
+                if (val >= _readGridIndices.Count)
                 {
-                    Logger.ErrorS("map", "Error in map file: found local grid ID '{0}' which does not exist.", val);
-                }
-                else
-                {
-                    return new DeserializedValue<GridId>(Grids[val].Index);
+                    throw new MapLoadException($"Error in map file: found local grid ID '{val}' which does not exist.");
                 }
 
-                return new DeserializedValue<GridId>(GridId.Invalid);
+                return new DeserializedValue<GridId>(_readGridIndices[val]);
             }
 
             ValidationNode ITypeValidator<EntityUid, ValueDataNode>.Validate(ISerializationManager serializationManager,

Robust.Server/Maps/YamlGridSerializer.cs

@@ -36,7 +36,7 @@ namespace Robust.Server.Maps
             return gridn;
         }
 
-        private static YamlNode SerializeChunk(IMapChunk chunk)
+        private static YamlNode SerializeChunk(MapChunk chunk)
         {
             var root = new YamlMappingNode();
             var value = new YamlScalarNode($"{chunk.X},{chunk.Y}");
@@ -51,7 +51,7 @@ namespace Robust.Server.Maps
             return root;
         }
 
-        private static string SerializeTiles(IMapChunk chunk)
+        private static string SerializeTiles(MapChunk chunk)
         {
             // number of bytes written per tile, because sizeof(Tile) is useless.
             const int structSize = 4;
@@ -68,7 +68,8 @@ namespace Robust.Server.Maps
                     {
                         var tile = chunk.GetTile(x, y);
                         writer.Write(tile.TypeId);
-                        writer.Write(tile.Data);
+                        writer.Write((byte)tile.Flags);
+                        writer.Write(tile.Variant);
                     }
                 }
             }
@@ -76,38 +77,10 @@ namespace Robust.Server.Maps
             return Convert.ToBase64String(barr);
         }
 
-        public static MapGrid DeserializeGrid(IMapManagerInternal mapMan, MapId mapId, YamlMappingNode info,
-            YamlSequenceNode chunks, IReadOnlyDictionary<ushort, string> tileDefMapping,
+        public static void DeserializeChunk(IMapManager mapMan, IMapGridInternal grid,
+            YamlMappingNode chunkData,
+            IReadOnlyDictionary<ushort, string> tileDefMapping,
             ITileDefinitionManager tileDefinitionManager)
-        {
-            ushort csz = 0;
-            ushort tsz = 0;
-            float sgsz = 0.0f;
-
-            foreach (var kvInfo in info)
-            {
-                var key = kvInfo.Key.ToString();
-                var val = kvInfo.Value.ToString();
-                if (key == "chunksize")
-                    csz = ushort.Parse(val);
-                else if (key == "tilesize")
-                    tsz = ushort.Parse(val);
-                else if (key == "snapsize")
-                    sgsz = float.Parse(val, CultureInfo.InvariantCulture);
-            }
-
-            //TODO: Pass in options
-            var grid = mapMan.CreateUnboundGrid(mapId);
-
-            foreach (var chunkNode in chunks.Cast<YamlMappingNode>())
-            {
-                DeserializeChunk(mapMan, grid, chunkNode, tileDefMapping, tileDefinitionManager);
-            }
-
-            return grid;
-        }
-
-        private static void DeserializeChunk(IMapManager mapMan, IMapGridInternal grid, YamlMappingNode chunkData, IReadOnlyDictionary<ushort, string> tileDefMapping, ITileDefinitionManager tileDefinitionManager)
         {
             var indNode = chunkData["ind"];
             var tileNode = chunkData["tiles"];
@@ -129,12 +102,13 @@ namespace Robust.Server.Maps
                 for (ushort x = 0; x < grid.ChunkSize; x++)
                 {
                     var id = reader.ReadUInt16();
-                    var data = reader.ReadUInt16();
+                    var flags = (TileRenderFlag)reader.ReadByte();
+                    var variant = reader.ReadByte();
 
                     var defName = tileDefMapping[id];
                     id = tileDefinitionManager[defName].TileId;
 
-                    var tile = new Tile(id, data);
+                    var tile = new Tile(id, flags, variant);
                     chunk.SetTile(x, y, tile);
                 }
             }

Robust.Server/Placement/PlacementManager.cs

@@ -209,7 +209,7 @@ namespace Robust.Server.Placement
         {
             EntityCoordinates start = msg.EntityCoordinates;
             Vector2 rectSize = msg.RectSize;
-            foreach (EntityUid entity in IoCManager.Resolve<IEntityLookup>().GetEntitiesIntersecting(start.GetMapId(_entityManager),
+            foreach (EntityUid entity in EntitySystem.Get<EntityLookupSystem>().GetEntitiesIntersecting(start.GetMapId(_entityManager),
                 new Box2(start.Position, start.Position + rectSize)))
             {
                 if (_entityManager.Deleted(entity) || _entityManager.HasComponent<IMapGridComponent>(entity) || _entityManager.HasComponent<ActorComponent>(entity))

Robust.Server/Player/IPlayerSession.cs

@@ -44,6 +44,8 @@ namespace Robust.Server.Player
 
         IReadOnlySet<EntityUid> ViewSubscriptions { get; }
 
+        int ViewSubscriptionCount { get; }
+
         /// <summary>
         ///     Persistent data for this player.
         /// </summary>

Robust.Server/Player/PlayerSession.cs

@@ -39,6 +39,7 @@ namespace Robust.Server.Player
         }
 
         [ViewVariables] public IReadOnlySet<EntityUid> ViewSubscriptions => _viewSubscriptions;
+        public int ViewSubscriptionCount => _viewSubscriptions.Count;
 
         [ViewVariables] public INetChannel ConnectedClient { get; }
 

Robust.Server/Robust.Server.csproj

@@ -10,12 +10,12 @@
   </PropertyGroup>
   <Import Project="..\MSBuild\Robust.DefineConstants.targets" />
   <ItemGroup>
-    <PackageReference Include="JetBrains.Annotations" Version="2020.3.0" PrivateAssets="All" />
+    <PackageReference Include="JetBrains.Annotations" Version="2021.3.0" PrivateAssets="All" />
     <!--  -->
     <PackageReference Include="SQLitePCLRaw.bundle_e_sqlite3" Version="2.0.7" />
     <PackageReference Include="prometheus-net" Version="4.1.1" />
     <PackageReference Include="Serilog.Sinks.Loki" Version="4.0.0-beta3" />
-    <PackageReference Include="Microsoft.Extensions.Primitives" Version="5.0.0" />
+    <PackageReference Include="Microsoft.Extensions.Primitives" Version="6.0.0" />
     <PackageReference Include="prometheus-net.DotNetRuntime" Version="4.2.2" />
   </ItemGroup>
   <ItemGroup>

Robust.Server/ServerIoC.cs

@@ -50,7 +50,6 @@ namespace Robust.Server
             IoCManager.Register<IMapManagerInternal, NetworkedMapManager>();
             IoCManager.Register<INetworkedMapManager, NetworkedMapManager>();
             IoCManager.Register<IEntityManager, ServerEntityManager>();
-            IoCManager.Register<IEntityLookup, EntityLookup>();
             IoCManager.Register<IEntityNetworkManager, ServerEntityManager>();
             IoCManager.Register<IServerEntityNetworkManager, ServerEntityManager>();
             IoCManager.Register<IMapLoader, MapLoader>();

Robust.Shared.Maths/Box2i.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
@@ -135,5 +135,17 @@ namespace Robust.Shared.Maths
         {
             return $"({Left}, {Bottom}, {Right}, {Top})";
         }
+
+        /// <summary>
+        /// Multiplies each side of the box by the scalar.
+        /// </summary>
+        public Box2i Scale(int scalar)
+        {
+            return new Box2i(
+                Left * scalar,
+                Bottom * scalar,
+                Right * scalar,
+                Top * scalar);
+        }
     }
 }

Robust.Shared.Maths/Color.cs

@@ -880,7 +880,7 @@ namespace Robust.Shared.Maths
                 return color.Value;
             if (fallback.HasValue)
                 return fallback.Value;
-            throw new ArgumentException("Invalid color code and no fallback provided.", nameof(hexColor));
+            throw new ArgumentException($"Invalid color code \"{new string(hexColor)}\" and no fallback provided.", nameof(hexColor));
         }
 
         public static Color FromXaml(string name)

Robust.Shared.Maths/Robust.Shared.Maths.csproj

@@ -8,7 +8,7 @@
   </PropertyGroup>
   <Import Project="..\MSBuild\Robust.DefineConstants.targets" />
   <ItemGroup>
-    <PackageReference Include="JetBrains.Annotations" Version="2020.3.0" PrivateAssets="All" />
+    <PackageReference Include="JetBrains.Annotations" Version="2021.3.0" PrivateAssets="All" />
     <PackageReference Condition="'$(TargetFramework)' == 'net472'" Include="System.Runtime.CompilerServices.Unsafe" Version="4.5.2" />
   </ItemGroup>
 </Project>

Robust.Shared.Maths/Vector2.cs

@@ -130,6 +130,12 @@ namespace Robust.Shared.Maths
             return new((int) MathF.Floor(X), (int) MathF.Floor(Y));
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public readonly Vector2i Ceiled()
+        {
+            return new((int) MathF.Ceiling(X), (int) MathF.Ceiling(Y));
+        }
+
         /// <summary>
         ///     Subtracts a vector from another, returning a new vector.
         /// </summary>

Robust.Shared.Scripting/Robust.Shared.Scripting.csproj

@@ -10,10 +10,10 @@
   <Import Project="..\MSBuild\Robust.DefineConstants.targets" />
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Features" Version="3.8.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Scripting" Version="3.8.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="3.8.0" />
-    <PackageReference Include="JetBrains.Annotations" Version="2020.3.0" PrivateAssets="All" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Features" Version="4.0.1" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Scripting" Version="4.0.1" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.0.1" />
+    <PackageReference Include="JetBrains.Annotations" Version="2021.3.0" PrivateAssets="All" />
   </ItemGroup>
 
   <ItemGroup>

Robust.Shared/CVars.cs

@@ -128,13 +128,13 @@ namespace Robust.Shared
         /// The amount of new entities that can be sent to a client in a single game state, under PVS.
         /// </summary>
         public static readonly CVarDef<int> NetPVSNewEntityBudget =
-            CVarDef.Create("net.pvs_new_budget", 20, CVar.ARCHIVE | CVar.REPLICATED | CVar.SERVER);
+            CVarDef.Create("net.pvs_new_budget", 20, CVar.ARCHIVE | CVar.REPLICATED);
 
         /// <summary>
-        /// The amount of entity updates that can be sent to a client in a single game state, under PVS.
+        /// The amount of entered entities that can be sent to a client in a single game state, under PVS.
         /// </summary>
         public static readonly CVarDef<int> NetPVSEntityBudget =
-            CVarDef.Create("net.pvs_budget", 50, CVar.ARCHIVE | CVar.REPLICATED | CVar.SERVER);
+            CVarDef.Create("net.pvs_budget", 50, CVar.ARCHIVE | CVar.REPLICATED);
 
         /// <summary>
         /// Log late input messages from clients.
@@ -1006,6 +1006,17 @@ namespace Robust.Shared
         public static readonly CVarDef<bool> ResTexturePreloadCache =
             CVarDef.Create("res.texture_preload_cache", true, CVar.CLIENTONLY);
 
+        /// <summary>
+        /// Override seekability of resource streams returned by ResourceManager.
+        /// See <see cref="ContentPack.StreamSeekMode"/> for int values.
+        /// </summary>
+        /// <remarks>
+        /// This is intended to be a debugging tool primarily.
+        /// Non-default seek modes WILL result in worse performance.
+        /// </remarks>
+        public static readonly CVarDef<int> ResStreamSeekMode =
+            CVarDef.Create("res.stream_seek_mode", (int)ContentPack.StreamSeekMode.None);
+
         /*
          * DEBUG
          */

Robust.Shared/Configuration/NetConfigurationManager.cs

@@ -20,6 +20,16 @@ namespace Robust.Shared.Configuration
         /// </summary>
         void SetupNetworking();
 
+        /// <summary>
+        /// Get a replicated client CVar for a specific client.
+        /// </summary>
+        /// <typeparam name="T">CVar type.</typeparam>
+        /// <param name="channel">channel of the connected client.</param>
+        /// <param name="definition">The CVar.</param>
+        /// <returns>Replicated CVar of the client.</returns>
+        public T GetClientCVar<T>(INetChannel channel, CVarDef<T> definition) where T : notnull =>
+            GetClientCVar<T>(channel, definition.Name);
+
         /// <summary>
         /// Get a replicated client CVar for a specific client.
         /// </summary>

Robust.Shared/Console/CommandBuffer.cs

@@ -0,0 +1,81 @@
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Robust.Shared.Console;
+
+public sealed class CommandBuffer
+{
+    private const string DelayMarker = "-DELAY-";
+
+    private int _tickrate = 0;
+    private int _delay = 0;
+
+    private readonly LinkedList<string> _commandBuffer = new();
+
+    public void Append(string command)
+    {
+        _commandBuffer.AddLast(command);
+    }
+
+    public void Insert(string command)
+    {
+        _commandBuffer.AddFirst(command);
+    }
+
+    public void Tick(byte tickRate)
+    {
+        _tickrate = tickRate;
+
+        if (_delay > 0)
+        {
+            _delay -= 1;
+        }
+    }
+
+    public bool TryGetCommand([MaybeNullWhen(false)]out string command)
+    {
+        var next = _commandBuffer.First;
+
+        if (next is null) // nothing to do here
+        {
+            command = null;
+            return false;
+        }
+
+        if (next.Value.Equals(DelayMarker))
+        {
+            if (_delay == 0) // just finished
+            {
+                _commandBuffer.RemoveFirst();
+                return TryGetCommand(out command);
+            }
+            else // currently counting down delay
+            {
+                command = null;
+                return false;
+            }
+        }
+
+        if (next.Value.StartsWith("wait "))
+        {
+            var sTicks = next.Value.Substring(5);
+            _commandBuffer.RemoveFirst();
+            if (string.IsNullOrWhiteSpace(sTicks) || !int.TryParse(sTicks, out var ticks)) // messed up command
+            {
+                return TryGetCommand(out command);
+            }
+
+            // Setup Timing
+            _commandBuffer.AddFirst(DelayMarker);
+            _delay = ticks;
+
+            command = null;
+            return false;
+        }
+
+        // normal command
+        _commandBuffer.RemoveFirst();
+        command = next.Value;
+        return true;
+    }
+}

Robust.Shared/Console/Commands/ExecCommand.cs

@@ -48,7 +48,7 @@ namespace Robust.Shared.Console.Commands
                     continue;
                 }
 
-                shell.ExecuteCommand(line);
+                shell.ConsoleHost.AppendCommand(line);
             }
         }
     }

Robust.Shared/Console/ConsoleHost.cs

@@ -7,6 +7,7 @@ using Robust.Shared.Log;
 using Robust.Shared.Network;
 using Robust.Shared.Players;
 using Robust.Shared.Reflection;
+using Robust.Shared.Timing;
 using Robust.Shared.ViewVariables;
 
 namespace Robust.Shared.Console
@@ -17,13 +18,16 @@ namespace Robust.Shared.Console
         protected const string SawmillName = "con";
 
         [Dependency] protected readonly ILogManager LogManager = default!;
-        [Dependency] protected readonly IReflectionManager ReflectionManager = default!;
+        [Dependency] private readonly IReflectionManager ReflectionManager = default!;
         [Dependency] protected readonly INetManager NetManager = default!;
         [Dependency] private readonly IDynamicTypeFactoryInternal _typeFactory = default!;
+        [Dependency] private readonly IGameTiming _timing = default!;
 
         [ViewVariables]
         protected readonly Dictionary<string, IConsoleCommand> AvailableCommands = new();
 
+        private readonly CommandBuffer _commandBuffer = new CommandBuffer();
+
         /// <inheritdoc />
         public bool IsServer => NetManager.IsServer;
 
@@ -116,6 +120,36 @@ namespace Robust.Shared.Console
             ExecuteCommand(null, command);
         }
 
+        /// <inheritdoc />
+        public void AppendCommand(string command)
+        {
+            _commandBuffer.Append(command);
+        }
+
+        /// <inheritdoc />
+        public void InsertCommand(string command)
+        {
+            _commandBuffer.Insert(command);
+        }
+
+        /// <inheritdoc />
+        public void CommandBufferExecute()
+        {
+            _commandBuffer.Tick(_timing.TickRate);
+
+            while (_commandBuffer.TryGetCommand(out var cmd))
+            {
+                try
+                {
+                    ExecuteCommand(cmd);
+                }
+                catch (Exception e)
+                {
+                    LocalShell.WriteError(e.Message);
+                }
+            }
+        }
+
         /// <summary>
         /// A console command that was registered inline through <see cref="IConsoleHost"/>.
         /// </summary>

Robust.Shared/Console/IConsoleHost.cs

@@ -81,11 +81,35 @@ namespace Robust.Shared.Console
         IConsoleShell GetSessionShell(ICommonSession session);
 
         /// <summary>
-        /// Execute a command string on the local shell.
+        /// Execute a command string immediately on the local shell, bypassing the command buffer completely.
         /// </summary>
         /// <param name="command">Command string to execute.</param>
         void ExecuteCommand(string command);
 
+        /// <summary>
+        /// Appends a command into the end of the command buffer on the local shell.
+        /// </summary>
+        /// <remarks>
+        ///  This command will be ran *sometime* in the future, depending on how many waits are in the buffer.
+        /// </remarks>
+        /// <param name="command">Command string to execute.</param>
+        void AppendCommand(string command);
+
+        /// <summary>
+        /// Inserts a command into the front of the command buffer on the local shell.
+        /// </summary>
+        /// <remarks>
+        ///  This command will preempt the next command executed in the command buffer.
+        /// </remarks>
+        /// <param name="command">Command string to execute.</param>
+        void InsertCommand(string command);
+
+        /// <summary>
+        /// Processes any contents of the command buffer on the local shell. This needs to be called regularly (once a tick),
+        /// inside the simulation. Pausing the server should prevent the buffer from being processed.
+        /// </summary>
+        void CommandBufferExecute();
+
         /// <summary>
         /// Executes a command string on this specific session shell. If the command does not exist, the command will be forwarded
         /// to the

Robust.Shared/Containers/BaseContainer.cs

@@ -81,6 +81,7 @@ namespace Robust.Shared.Containers
             // spatially move the object to the location of the container. If you don't want this functionality, the
             // calling code can save the local position before calling this function, and apply it afterwords.
             transform.LocalPosition = Vector2.Zero;
+            transform.LocalRotation = Angle.Zero;
 
             return true;
         }

Robust.Shared/Containers/SharedContainerSystem.cs

@@ -209,6 +209,43 @@ namespace Robust.Shared.Containers
             return false;
         }
 
+        /// <summary>
+        /// Gets the top-most container in the hierarchy for this entity, if it exists.
+        /// </summary>
+        public bool TryGetOuterContainer(EntityUid uid, TransformComponent xform, [NotNullWhen(true)] out IContainer? container)
+        {
+            var xformQuery = EntityManager.GetEntityQuery<TransformComponent>();
+            return TryGetOuterContainer(uid, xform, out container, xformQuery);
+        }
+
+        public bool TryGetOuterContainer(EntityUid uid, TransformComponent xform,
+            [NotNullWhen(true)] out IContainer? container, EntityQuery<TransformComponent> xformQuery)
+        {
+            container = null;
+
+            if (!uid.IsValid())
+                return false;
+
+            var conQuery = EntityManager.GetEntityQuery<ContainerManagerComponent>();
+            var child = uid;
+            var parent = xform.ParentUid;
+
+            while (parent.IsValid())
+            {
+                if (conQuery.TryGetComponent(parent, out var conManager) &&
+                    conManager.TryGetContainer(child, out var parentContainer))
+                {
+                    container = parentContainer;
+                }
+
+                var parentXform = xformQuery.GetComponent(parent);
+                child = parent;
+                parent = parentXform.ParentUid;
+            }
+
+            return container != null;
+        }
+
         #endregion
 
         // Eject entities from their parent container if the parent change is done by the transform only.

Robust.Shared/ContentPack/AssemblyTypeChecker.cs

@@ -111,7 +111,7 @@ namespace Robust.Shared.ContentPack
             var fullStopwatch = Stopwatch.StartNew();
 
             var resolver = CreateResolver();
-            using var peReader = new PEReader(assembly, PEStreamOptions.LeaveOpen);
+            using var peReader = ModLoader.MakePEReader(assembly, leaveOpen: true);
             var reader = peReader.GetMetadataReader();
 
             var asmName = reader.GetString(reader.GetAssemblyDefinition().Name);
@@ -853,13 +853,13 @@ namespace Robust.Shared.ContentPack
                         continue;
                     }
 
-                    return ReaderFromStream(File.OpenRead(path));
+                    return ModLoader.MakePEReader(File.OpenRead(path));
                 }
 
                 var extraStream = _parent.ExtraRobustLoader?.Invoke(dllName);
                 if (extraStream != null)
                 {
-                    return ReaderFromStream(extraStream);
+                    return ModLoader.MakePEReader(extraStream);
                 }
 
                 foreach (var resLoadPath in _resLoadPaths)
@@ -867,7 +867,7 @@ namespace Robust.Shared.ContentPack
                     try
                     {
                         var path = resLoadPath / dllName;
-                        return ReaderFromStream(_parent._res.ContentFileRead(path));
+                        return ModLoader.MakePEReader(_parent._res.ContentFileRead(path));
                     }
                     catch (FileNotFoundException)
                     {
@@ -877,23 +877,6 @@ namespace Robust.Shared.ContentPack
                 return null;
             }
 
-            private static PEReader ReaderFromStream(Stream stream)
-            {
-                if (OperatingSystem.IsLinux() && stream is FileStream)
-                {
-                    // PEReader is bugged on Linux and not properly thread safe when doing memory mapping.
-                    // As such, we never pass it a file stream so it uses a different, non-bugged code path.
-                    // See https://github.com/dotnet/runtime/issues/60545
-                    var ms = new MemoryStream();
-                    stream.CopyTo(ms);
-                    ms.Seek(0, SeekOrigin.Begin);
-                    stream.Dispose();
-                    stream = ms;
-                }
-
-                return new PEReader(stream);
-            }
-
             public PEReader? Resolve(string simpleName)
             {
                 return _dictionary.GetOrAdd(simpleName, ResolveCore);