Version: 252.0.1

commit d4f265c314
Author: PJB3005 <pieterjan.briers+git@gmail.com>
Date:   Sun Sep 14 14:32:44 2025 +0200

    Fix incorrect path combine in DirLoader and WritableDirProvider

    This (and the other couple past commits) reported by Elelzedel.

commit 7654d38612
Author: PJB3005 <pieterjan.briers+git@gmail.com>
Date:   Sat Sep 13 22:50:51 2025 +0200

    Move CEF cache out of data directory

    Don't want content messing with this...

commit cdcc255123
Author: PJB3005 <pieterjan.briers+git@gmail.com>
Date:   Sat Sep 13 19:11:16 2025 +0200

    Make Robust.Client.WebView.Cef.Program internal.

commit 2f56a6a110
Author: PJB3005 <pieterjan.briers+git@gmail.com>
Date:   Sat Sep 13 19:10:46 2025 +0200

    Update SpaceWizards.NFluidSynth to 0.2.2

commit 16fc48cef2
Author: PJB3005 <pieterjan.briers+git@gmail.com>
Date:   Sat Sep 13 19:09:43 2025 +0200

    Hide IWritableDirProvider.RootDir on client

    This shouldn't be exposed.

(cherry picked from commit 2f07159336bc640e41fbbccfdec4133a68c13bdb)
(cherry picked from commit d6c3212c74373ed2420cc4be2cf10fcd899c2106)
(cherry picked from commit bfa70d7e2ca6758901b680547fcfa9b24e0610b7)
(cherry picked from commit 06e52f5d58efc1491915822c2650f922673c82c6)

Directory.Packages.props

@@ -57,7 +57,7 @@
     <PackageVersion Include="SharpZstd.Interop" Version="1.5.2-beta2" />
     <PackageVersion Include="SixLabors.ImageSharp" Version="3.1.7" />
     <PackageVersion Include="SpaceWizards.HttpListener" Version="0.1.1" />
-    <PackageVersion Include="SpaceWizards.NFluidsynth" Version="0.1.1" />
+    <PackageVersion Include="SpaceWizards.NFluidsynth" Version="0.2.2" />
     <PackageVersion Include="SpaceWizards.SharpFont" Version="1.0.2" />
     <PackageVersion Include="SpaceWizards.Sodium" Version="0.2.1" />
     <PackageVersion Include="TerraFX.Interop.Windows" Version="10.0.26100.1" />

MSBuild/Robust.Engine.Version.props

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

RELEASE-NOTES.md

@@ -54,6 +54,105 @@ END TEMPLATE-->
 *None yet*
 
 
+## 252.0.1
+
+
+## 252.0.0
+
+### Breaking changes
+
+* BoundUserInterfaceMessageAttempt is raised directed against entities and no longer broadcast.
+
+
+## 251.0.0
+
+### Breaking changes
+
+* Localization is now separate between client and server and is handled via cvar.
+* Contacting entities no longer can be disabled for CollisionWake to avoid destroying the contacts unnecessarily.
+
+### New features
+
+* Added `DirectionExtensions.AllDirections`, which contains a list of all `Direction`s for easy enumeration.
+* Add ForbidLiteralAttribute.
+* Log late MsgEntity again.
+* Show entity name in `physics shapeinfo` output.
+* Make SubscribeLocalEvent not require EntityEventArgs.
+* Add autocomplete to `tp` command.
+* Add button to jump to live chat when scrolled up.
+* Add autocomplete to `savemap` and `savegrid`.
+
+### Bugfixes
+
+* Fix velocity not re-applying correctly on re-parenting.
+* Fix Equatable on FormattedMessage.
+* Fix SharedTransformSystem methods logging errors on resolves.
+
+### Other
+
+* Significantly optimized tile edge rendering.
+
+### Internal
+
+* Remove duplicate GetMassData method.
+* Inline manifold points for physics.
+
+
+## 250.0.0
+
+### Breaking changes
+
+* The default shader now interprets negative color modulation as a flag that indicates that the light map should be ignored.
+  * This can be used to avoid having to change the light map texture, thus reducing draw batches.
+  * Sprite layers that are set to use the "unshaded" shader prototype now use this.
+  * Any fragment shaders that previously the `VtxModulate` colour modulation variable should instead use the new `MODULATE` variable, as the former may now contain negative values.
+
+### New features
+
+* Add OtherBody API to contacts.
+* Make FormattedMessages Equatable.
+* AnimationCompletionEvent now has the AnimationPlayerComponent.
+* Add entity description as a tooltip on the entity spawn panel.
+
+### Bugfixes
+
+* Fix serialization source generator breaking if a class has two partial locations.
+* Fix map saving throwing a `DirectoryNotFoundException` when given a path with a non-existent directory. Now it once again creates any missing directories.
+* Fix map loading taking a significant time due to MappingDataNode.Equals calls being slow.
+
+### Other
+
+* Add Pure to some Angle methods.
+
+### Internal
+
+* Cleanup some warnings in classes.
+
+
+## 249.0.0
+
+### Breaking changes
+
+* Layer is now read-only on VisibilityComponent and isn't serialized.
+
+### New features
+
+* Added a debug overlay for the linear and angular velocity of all entities on the screen. Use the `showvel` and `showangvel` commands to toggle it.
+* Add a GetWorldManifold overload that doesn't require a span of points.
+* Added a GetVisMaskEvent. Calling `RefreshVisibilityMask` will raise it and subscribers can update the vismask via the event rather than subscribers having to each manually try and handle the vismask directly.
+
+### Bugfixes
+
+* `BoxContainer` no longer causes stretching children to go below their minimum size.
+* Fix lights on other grids getting clipped due to ignoring the light range cvar.
+* Fix the `showvelocities` command.
+* Fix the DirtyFields overload not being sandbox safe for content.
+
+### Internal
+
+* Polygon vertices are now inlined with FixedArray8 and a separate SlimPolygon using FixedArray4 for hot paths rather than using pooled arrays.
+
+
 ## 248.0.2
 
 ### Bugfixes

Resources/Locale/en-US/commands.ftl

@@ -11,6 +11,7 @@ cmd-parse-failure-uid = {$arg} is not a valid entity UID.
 cmd-parse-failure-mapid = {$arg} is not a valid MapId.
 cmd-parse-failure-enum = {$arg} is not a {$enum} Enum.
 cmd-parse-failure-grid = {$arg} is not a valid grid.
+cmd-parse-failure-cultureinfo = "{$arg}" is not valid CultureInfo.
 cmd-parse-failure-entity-exist = UID {$arg} does not correspond to an existing entity.
 cmd-parse-failure-session = There is no session with username: {$username}
 
@@ -428,11 +429,20 @@ cmd-entfo-help = Usage: entfo <entityuid>
     The entity UID can be prefixed with 'c' to convert it to a client entity UID.
 
 cmd-fuck-desc = Throws an exception
-cmd-fuck-help = Throws an exception
+cmd-fuck-help = Usage: fuck
 
-cmd-showpos-desc = Enables debug drawing over all entity positions in the game.
+cmd-showpos-desc = Show the position of all entities on the screen.
 cmd-showpos-help = Usage: showpos
 
+cmd-showrot-desc = Show the rotation of all entities on the screen.
+cmd-showrot-help = Usage: showrot
+
+cmd-showvel-desc = Show the local velocity of all entites on the screen.
+cmd-showvel-help = Usage: showvel
+
+cmd-showangvel-desc = Show the angular velocity of all entities on the screen.
+cmd-showangvel-help = Usage: showangvel
+
 cmd-sggcell-desc = Lists entities on a snap grid cell.
 cmd-sggcell-help = Usage: sggcell <gridID> <vector2i>\nThat vector2i param is in the form x<int>,y<int>.
 
@@ -563,3 +573,8 @@ cmd-pvs-override-info-desc = Prints information about any PVS overrides associat
 cmd-pvs-override-info-empty = Entity {$nuid} has no PVS overrides.
 cmd-pvs-override-info-global = Entity {$nuid} has a global override.
 cmd-pvs-override-info-clients = Entity {$nuid} has a session override for {$clients}.
+
+cmd-localization_set_culture-desc = Set DefaultCulture for the client LocalizationManager
+cmd-localization_set_culture-help = Usage: localization_set_culture <cultureName>
+cmd-localization_set_culture-culture-name = <cultureName>
+cmd-localization_set_culture-changed = Localization changed to { $code } ({ $nativeName } / { $englishName })

Resources/Locale/en-US/custom-controls.ftl

@@ -14,6 +14,10 @@ tile-spawn-window-title = Place Tiles
 
 console-line-edit-placeholder = Command Here
 
+## OutputPanel
+
+output-panel-scroll-down-button-text = Scroll Down
+
 ## Common Used
 
 window-erase-button-text = Erase Mode

Robust.Analyzers.Tests/ForbidLiteralAnalyzerTest.cs

@@ -0,0 +1,189 @@
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.CSharp.Testing;
+using Microsoft.CodeAnalysis.Testing;
+using NUnit.Framework;
+using VerifyCS =
+    Microsoft.CodeAnalysis.CSharp.Testing.CSharpAnalyzerVerifier<Robust.Analyzers.ForbidLiteralAnalyzer, Microsoft.CodeAnalysis.Testing.DefaultVerifier>;
+
+
+namespace Robust.Analyzers.Tests;
+
+[Parallelizable(ParallelScope.All | ParallelScope.Fixtures)]
+[TestFixture]
+public sealed class ForbidLiteralAnalyzerTest
+{
+    private static Task Verifier(string code, params DiagnosticResult[] expected)
+    {
+        var test = new CSharpAnalyzerTest<ForbidLiteralAnalyzer, DefaultVerifier>()
+        {
+            TestState =
+            {
+                Sources = { code },
+            },
+        };
+
+        TestHelper.AddEmbeddedSources(
+            test.TestState,
+            "Robust.Shared.Analyzers.ForbidLiteralAttribute.cs"
+        );
+
+        test.TestState.Sources.Add(("TestTypeDefs.cs", TestTypeDefs));
+
+        // ExpectedDiagnostics cannot be set, so we need to AddRange here...
+        test.TestState.ExpectedDiagnostics.AddRange(expected);
+
+        return test.RunAsync();
+    }
+
+    private const string TestTypeDefs = """
+        using System.Collections.Generic;
+        using Robust.Shared.Analyzers;
+
+        public sealed class TestClass
+        {
+            public static void OneParameterForbidden([ForbidLiteral] string value) { }
+            public static void TwoParametersFirstForbidden([ForbidLiteral] string first, string second) { }
+            public static void TwoParametersBothForbidden([ForbidLiteral] string first, [ForbidLiteral] string second) { }
+            public static void ListParameterForbidden([ForbidLiteral] List<string> values) { }
+            public static void ParamsListParameterForbidden([ForbidLiteral] params List<string> values) { }
+        }
+
+        public record struct StringWrapper(string value)
+        {
+            private readonly string _value = value;
+
+            public static implicit operator string(StringWrapper wrapper)
+            {
+                return wrapper._value;
+            }
+        }
+    """;
+
+    [Test]
+    public async Task TestOneParameter()
+    {
+        const string code = """
+            public sealed class Tester
+            {
+                private const string _constValue = "foo";
+                private static readonly string StaticValue = "bar";
+                private static readonly StringWrapper WrappedValue = new("biz");
+
+                public void Test()
+                {
+                    TestClass.OneParameterForbidden(_constValue);
+                    TestClass.OneParameterForbidden(StaticValue);
+                    TestClass.OneParameterForbidden(WrappedValue);
+                    TestClass.OneParameterForbidden("baz");
+                }
+            }
+            """;
+
+        await Verifier(code,
+            // /0/Test0.cs(12,41): error RA0033: The "value" parameter of OneParameterForbidden forbids literal values
+            VerifyCS.Diagnostic().WithSpan(12, 41, 12, 46).WithArguments("value", "OneParameterForbidden")
+        );
+    }
+
+    [Test]
+    public async Task TestTwoParametersFirstForbidden()
+    {
+        const string code = """
+            public sealed class Tester
+            {
+                private const string _constValue = "foo";
+
+                public void Test()
+                {
+                    TestClass.TwoParametersFirstForbidden(_constValue, "whatever");
+                    TestClass.TwoParametersFirstForbidden(_constValue, _constValue);
+                    TestClass.TwoParametersFirstForbidden("foo", "whatever");
+                }
+            }
+            """;
+
+        await Verifier(code,
+            // /0/Test0.cs(9,47): error RA0033: The "first" parameter of TwoParametersFirstForbidden forbids literal values
+            VerifyCS.Diagnostic().WithSpan(9, 47, 9, 52).WithArguments("first", "TwoParametersFirstForbidden")
+        );
+    }
+
+    [Test]
+    public async Task TestTwoParametersBothForbidden()
+    {
+        const string code = """
+            public sealed class Tester
+            {
+                private const string _constValue = "foo";
+                private static readonly string StaticValue = "bar";
+
+                public void Test()
+                {
+                    TestClass.TwoParametersBothForbidden(_constValue, _constValue);
+                    TestClass.TwoParametersBothForbidden(_constValue, StaticValue);
+                    TestClass.TwoParametersBothForbidden(_constValue, "whatever");
+                    TestClass.TwoParametersBothForbidden("whatever", _constValue);
+                }
+            }
+            """;
+
+        await Verifier(code,
+            // /0/Test0.cs(10,59): error RA0033: The "second" parameter of TwoParametersBothForbidden forbids literal values
+            VerifyCS.Diagnostic().WithSpan(10, 59, 10, 69).WithArguments("second", "TwoParametersBothForbidden"),
+            // /0/Test0.cs(11,46): error RA0033: The "first" parameter of TwoParametersBothForbidden forbids literal values
+            VerifyCS.Diagnostic().WithSpan(11, 46, 11, 56).WithArguments("first", "TwoParametersBothForbidden")
+        );
+    }
+
+    [Test]
+    public async Task TestListParameter()
+    {
+        const string code = """
+            public sealed class Tester
+            {
+                private const string _constValue = "foo";
+                private static readonly string StaticValue = "bar";
+                private static readonly StringWrapper WrappedValue = new("biz");
+
+                public void Test()
+                {
+                    TestClass.ListParameterForbidden([_constValue, StaticValue, WrappedValue]);
+                    TestClass.ListParameterForbidden(["foo", _constValue, "bar"]);
+                }
+            }
+            """;
+
+        await Verifier(code,
+            // /0/Test0.cs(10,43): warning RA0033: The "values" parameter of ListParameterForbidden forbids literal values
+            VerifyCS.Diagnostic().WithSpan(10, 43, 10, 48).WithArguments("values", "ListParameterForbidden"),
+            // /0/Test0.cs(10,63): warning RA0033: The "values" parameter of ListParameterForbidden forbids literal values
+            VerifyCS.Diagnostic().WithSpan(10, 63, 10, 68).WithArguments("values", "ListParameterForbidden")
+        );
+    }
+
+    [Test]
+    public async Task TestParamsListParameter()
+    {
+        const string code = """
+            public sealed class Tester
+            {
+                private const string _constValue = "foo";
+                private static readonly string StaticValue = "bar";
+                private static readonly StringWrapper WrappedValue = new("biz");
+
+                public void Test()
+                {
+                    TestClass.ParamsListParameterForbidden(_constValue, StaticValue, WrappedValue);
+                    TestClass.ParamsListParameterForbidden("foo", _constValue, "bar");
+                }
+            }
+            """;
+
+        await Verifier(code,
+            // /0/Test0.cs(10,48): warning RA0033: The "values" parameter of ParamsListParameterForbidden forbids literal values
+            VerifyCS.Diagnostic().WithSpan(10, 48, 10, 53).WithArguments("values", "ParamsListParameterForbidden"),
+            // /0/Test0.cs(10,68): warning RA0033: The "values" parameter of ParamsListParameterForbidden forbids literal values
+            VerifyCS.Diagnostic().WithSpan(10, 68, 10, 73).WithArguments("values", "ParamsListParameterForbidden")
+        );
+    }
+}

Robust.Analyzers.Tests/Robust.Analyzers.Tests.csproj

@@ -13,6 +13,7 @@
     <EmbeddedResource Include="..\Robust.Shared\Analyzers\MustCallBaseAttribute.cs" LogicalName="Robust.Shared.IoC.MustCallBaseAttribute.cs" LinkBase="Implementations" />
     <EmbeddedResource Include="..\Robust.Shared\Analyzers\PreferNonGenericVariantForAttribute.cs" LogicalName="Robust.Shared.Analyzers.PreferNonGenericVariantForAttribute.cs" LinkBase="Implementations" />
     <EmbeddedResource Include="..\Robust.Shared\Analyzers\PreferOtherTypeAttribute.cs" LogicalName="Robust.Shared.Analyzers.PreferOtherTypeAttribute.cs" LinkBase="Implementations" />
+    <EmbeddedResource Include="..\Robust.Shared\Analyzers\ForbidLiteralAttribute.cs" LogicalName="Robust.Shared.Analyzers.ForbidLiteralAttribute.cs" LinkBase="Implementations" />
     <EmbeddedResource Include="..\Robust.Shared\IoC\DependencyAttribute.cs" LogicalName="Robust.Shared.IoC.DependencyAttribute.cs" LinkBase="Implementations" />
     <EmbeddedResource Include="..\Robust.Shared\GameObjects\EventBusAttributes.cs" LogicalName="Robust.Shared.GameObjects.EventBusAttributes.cs" LinkBase="Implementations" />
   </ItemGroup>

Robust.Analyzers/ForbidLiteralAnalyzer.cs

@@ -0,0 +1,101 @@
+using System.Collections.Immutable;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Microsoft.CodeAnalysis.Operations;
+using Robust.Roslyn.Shared;
+
+namespace Robust.Analyzers;
+
+[DiagnosticAnalyzer(LanguageNames.CSharp)]
+public sealed class ForbidLiteralAnalyzer : DiagnosticAnalyzer
+{
+    private const string ForbidLiteralType = "Robust.Shared.Analyzers.ForbidLiteralAttribute";
+
+    public static DiagnosticDescriptor ForbidLiteralRule = new(
+        Diagnostics.IdForbidLiteral,
+        "Parameter forbids literal values",
+        "The {0} parameter of {1} forbids literal values",
+        "Usage",
+        DiagnosticSeverity.Warning,
+        true,
+        "Pass in a validated wrapper type like ProtoId, or a const or static value."
+    );
+
+    public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics => [ForbidLiteralRule];
+
+    public override void Initialize(AnalysisContext context)
+    {
+        context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.Analyze | GeneratedCodeAnalysisFlags.ReportDiagnostics);
+        context.EnableConcurrentExecution();
+        context.RegisterOperationAction(AnalyzeOperation, OperationKind.Invocation);
+    }
+
+    private void AnalyzeOperation(OperationAnalysisContext context)
+    {
+        if (context.Operation is not IInvocationOperation invocationOperation)
+            return;
+
+        // Check each parameter of the method invocation
+        foreach (var argumentOperation in invocationOperation.Arguments)
+        {
+            // Check for our attribute on the parameter
+            if (!AttributeHelper.HasAttribute(argumentOperation.Parameter, ForbidLiteralType, out _))
+                continue;
+
+            // Handle parameters using the params keyword
+            if (argumentOperation.Syntax is InvocationExpressionSyntax subExpressionSyntax)
+            {
+                // Check each param value
+                foreach (var subArgument in subExpressionSyntax.ArgumentList.Arguments)
+                {
+                    CheckArgumentSyntax(context, argumentOperation, subArgument);
+                }
+                continue;
+            }
+
+            // Not params, so just check the single parameter
+            if (argumentOperation.Syntax is not ArgumentSyntax argumentSyntax)
+                continue;
+
+            CheckArgumentSyntax(context, argumentOperation, argumentSyntax);
+        }
+    }
+
+    private void CheckArgumentSyntax(OperationAnalysisContext context, IArgumentOperation operation, ArgumentSyntax argumentSyntax)
+    {
+        // Handle collection types
+        if (argumentSyntax.Expression is CollectionExpressionSyntax collectionExpressionSyntax)
+        {
+            // Check each value of the collection
+            foreach (var elementSyntax in collectionExpressionSyntax.Elements)
+            {
+                if (elementSyntax is not ExpressionElementSyntax expressionSyntax)
+                    continue;
+
+                // Check if a literal was passed in
+                if (expressionSyntax.Expression is not LiteralExpressionSyntax)
+                    continue;
+
+                context.ReportDiagnostic(Diagnostic.Create(ForbidLiteralRule,
+                    expressionSyntax.GetLocation(),
+                    operation.Parameter.Name,
+                    (context.Operation as IInvocationOperation).TargetMethod.Name
+                ));
+            }
+            return;
+        }
+
+        // Not a collection, just a single value to check
+        // Check if it's a literal
+        if (argumentSyntax.Expression is not LiteralExpressionSyntax)
+            return;
+
+        context.ReportDiagnostic(Diagnostic.Create(ForbidLiteralRule,
+            argumentSyntax.GetLocation(),
+            operation.Parameter.Name,
+            (context.Operation as IInvocationOperation).TargetMethod.Name
+        ));
+    }
+}

Robust.Client.WebView/Cef/Program.cs

@@ -6,7 +6,7 @@ using Xilium.CefGlue;
 
 namespace Robust.Client.WebView.Cef
 {
-    public static class Program
+    internal static class Program
     {
         // This was supposed to be the main entry for the subprocess program... It doesn't work.
         public static int Main(string[] args)

Robust.Client.WebView/Cef/WebViewManagerCef.cs

@@ -5,6 +5,7 @@ using System.Net;
 using System.Reflection;
 using System.Text;
 using Robust.Client.Console;
+using Robust.Client.Utility;
 using Robust.Shared.Configuration;
 using Robust.Shared.ContentPack;
 using Robust.Shared.IoC;
@@ -24,6 +25,7 @@ namespace Robust.Client.WebView.Cef
 
         [Dependency] private readonly IDependencyCollection _dependencyCollection = default!;
         [Dependency] private readonly IPrototypeManager _prototypeManager = default!;
+        [Dependency] private readonly IGameControllerInternal _gameController = default!;
         [Dependency] private readonly IResourceManagerInternal _resourceManager = default!;
         [Dependency] private readonly IClientConsoleHost _consoleHost = default!;
         [Dependency] private readonly IConfigurationManager _cfg = default!;
@@ -61,7 +63,10 @@ namespace Robust.Client.WebView.Cef
 
             var cachePath = "";
             if (_resourceManager.UserData is WritableDirProvider userData)
-                cachePath = userData.GetFullPath(new ResPath("/cef_cache"));
+            {
+                var rootDir = UserDataDir.GetRootUserDataDir(_gameController);
+                cachePath = Path.Combine(rootDir, "cef_cache", "0");
+            }
 
             var settings = new CefSettings()
             {

Robust.Client/Console/Commands/Debug.cs

@@ -173,29 +173,51 @@ namespace Robust.Client.Console.Commands
         }
     }
 
-    internal sealed class ShowPositionsCommand : LocalizedCommands
+    internal sealed class ShowPositionsCommand : LocalizedEntityCommands
     {
-        [Dependency] private readonly IEntitySystemManager _entitySystems = default!;
+        [Dependency] private readonly DebugDrawingSystem _debugDrawing = default!;
 
         public override string Command => "showpos";
 
         public override void Execute(IConsoleShell shell, string argStr, string[] args)
         {
-            var mgr = _entitySystems.GetEntitySystem<DebugDrawingSystem>();
-            mgr.DebugPositions = !mgr.DebugPositions;
+            _debugDrawing.DebugPositions = !_debugDrawing.DebugPositions;
         }
     }
 
-    internal sealed class ShowRotationsCommand : LocalizedCommands
+    internal sealed class ShowRotationsCommand : LocalizedEntityCommands
     {
-        [Dependency] private readonly IEntitySystemManager _entitySystems = default!;
+        [Dependency] private readonly DebugDrawingSystem _debugDrawing = default!;
 
         public override string Command => "showrot";
 
         public override void Execute(IConsoleShell shell, string argStr, string[] args)
         {
-            var mgr = _entitySystems.GetEntitySystem<DebugDrawingSystem>();
-            mgr.DebugRotations = !mgr.DebugRotations;
+            _debugDrawing.DebugRotations = !_debugDrawing.DebugRotations;
+        }
+    }
+
+    internal sealed class ShowVelocitiesCommand : LocalizedEntityCommands
+    {
+        [Dependency] private readonly DebugDrawingSystem _debugDrawing = default!;
+
+        public override string Command => "showvel";
+
+        public override void Execute(IConsoleShell shell, string argStr, string[] args)
+        {
+            _debugDrawing.DebugVelocities = !_debugDrawing.DebugVelocities;
+        }
+    }
+
+    internal sealed class ShowAngularVelocitiesCommand : LocalizedEntityCommands
+    {
+        [Dependency] private readonly DebugDrawingSystem _debugDrawing = default!;
+
+        public override string Command => "showangvel";
+
+        public override void Execute(IConsoleShell shell, string argStr, string[] args)
+        {
+            _debugDrawing.DebugAngularVelocities = !_debugDrawing.DebugAngularVelocities;
         }
     }
 

Robust.Client/Console/Commands/LocalizationCommands.cs

@@ -0,0 +1,67 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using JetBrains.Annotations;
+using Robust.Shared.Console;
+using Robust.Shared.Localization;
+
+namespace Robust.Client.Console.Commands;
+
+[UsedImplicitly]
+internal sealed class LocalizationSetCulture : LocalizedCommands
+{
+    private const string Name = "localization_set_culture";
+    private const int ArgumentCount = 1;
+
+    public override string Command => Name;
+
+    public override void Execute(IConsoleShell shell, string argStr, string[] args)
+    {
+        if (args.Length != ArgumentCount)
+        {
+            shell.WriteError(Loc.GetString("cmd-invalid-arg-number-error"));
+            return;
+        }
+
+        CultureInfo culture;
+        try
+        {
+            culture = CultureInfo.GetCultureInfo(args[0], predefinedOnly: false);
+        }
+        catch (CultureNotFoundException)
+        {
+            shell.WriteError(Loc.GetString("cmd-parse-failure-cultureinfo", ("arg", args[0])));
+            return;
+        }
+
+        LocalizationManager.SetCulture(culture);
+        shell.WriteLine(LocalizationManager.GetString("cmd-localization_set_culture-changed",
+            ("code", culture.Name),
+            ("nativeName", culture.NativeName),
+            ("englishName", culture.EnglishName)));
+    }
+
+    public override CompletionResult GetCompletion(IConsoleShell shell, string[] args)
+    {
+        return args.Length switch
+        {
+            1 => CompletionResult.FromHintOptions(GetCultureNames(),
+                LocalizationManager.GetString("cmd-localization_set_culture-culture-name")),
+            _ => CompletionResult.Empty
+        };
+    }
+
+    private static HashSet<string> GetCultureNames()
+    {
+        var cultureInfos = CultureInfo.GetCultures(CultureTypes.AllCultures)
+            .Where(x => !string.IsNullOrEmpty(x.Name))
+            .ToArray();
+
+        var allNames = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+        allNames.UnionWith(cultureInfos.Select(x => x.TwoLetterISOLanguageName));
+        allNames.UnionWith(cultureInfos.Select(x => x.Name));
+
+        return allNames;
+    }
+}

Robust.Client/Console/Commands/ShowPlayerVelocityCommand.cs

@@ -5,15 +5,15 @@ using Robust.Shared.IoC;
 
 namespace Robust.Client.Console.Commands
 {
-    public sealed class VelocitiesCommand : LocalizedCommands
+    public sealed class ShowPlayerVelocityCommand : LocalizedCommands
     {
         [Dependency] private readonly IEntitySystemManager _entitySystems = default!;
 
-        public override string Command => "showvelocities";
+        public override string Command => "showplayervelocity";
 
         public override void Execute(IConsoleShell shell, string argStr, string[] args)
         {
-            _entitySystems.GetEntitySystem<VelocityDebugSystem>().Enabled ^= true;
+            _entitySystems.GetEntitySystem<ShowPlayerVelocityDebugSystem>().Enabled ^= true;
         }
     }
 }

Robust.Client/Debugging/DebugDrawingSystem.cs

@@ -1,140 +1,221 @@
-using System.Numerics;
-using Robust.Client.GameObjects;
 using Robust.Client.Graphics;
 using Robust.Shared.Enums;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
 using Robust.Shared.Maths;
+using Robust.Shared.Physics.Components;
+using System.Numerics;
 
-namespace Robust.Client.Debugging
+namespace Robust.Client.Debugging;
+
+/// <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 EntityLookupSystem _lookup = default!;
+    [Dependency] private readonly SharedTransformSystem _transform = default!;
+
+    private bool _debugPositions;
+    private bool _debugRotations;
+    private bool _debugVelocities;
+    private bool _debugAngularVelocities;
+
     /// <summary>
-    /// A collection of visual debug overlays for the client game.
+    /// Toggles the visual overlay of the local origin for each entity on screen.
     /// </summary>
-    public sealed class DebugDrawingSystem : EntitySystem
+    public bool DebugPositions
     {
-        [Dependency] private readonly IOverlayManager _overlayManager = default!;
-        [Dependency] private readonly EntityLookupSystem _lookup = default!;
-        [Dependency] private readonly TransformSystem _transform = default!;
-
-
-        private bool _debugPositions;
-        private bool _debugRotations;
-
-        /// <summary>
-        /// Toggles the visual overlay of the local origin for each entity on screen.
-        /// </summary>
-        public bool DebugPositions
+        get => _debugPositions;
+        set
         {
-            get => _debugPositions;
-            set
+            if (value == DebugPositions)
             {
-                if (value == DebugPositions)
-                {
-                    return;
-                }
+                return;
+            }
 
-                _debugPositions = value;
+            _debugPositions = value;
 
-                if (value && !_overlayManager.HasOverlay<EntityPositionOverlay>())
-                {
-                    _overlayManager.AddOverlay(new EntityPositionOverlay(_lookup, EntityManager, _transform));
-                }
-                else
-                {
-                    _overlayManager.RemoveOverlay<EntityPositionOverlay>();
-                }
+            if (value && !_overlayManager.HasOverlay<EntityPositionOverlay>())
+            {
+                _overlayManager.AddOverlay(new EntityPositionOverlay(_lookup, _transform));
+            }
+            else
+            {
+                _overlayManager.RemoveOverlay<EntityPositionOverlay>();
             }
         }
+    }
 
-        /// <summary>
-        /// Toggles the visual overlay of the local rotation.
-        /// </summary>
-        public bool DebugRotations
+    /// <summary>
+    /// Toggles the visual overlay of the rotation for each entity on screen.
+    /// </summary>
+    public bool DebugRotations
+    {
+        get => _debugRotations;
+        set
         {
-            get => _debugRotations;
-            set
+            if (value == DebugRotations)
             {
-                if (value == DebugRotations)
-                {
-                    return;
-                }
+                return;
+            }
 
-                _debugRotations = value;
+            _debugRotations = value;
 
-                if (value && !_overlayManager.HasOverlay<EntityRotationOverlay>())
-                {
-                    _overlayManager.AddOverlay(new EntityRotationOverlay(_lookup, EntityManager));
-                }
-                else
-                {
-                    _overlayManager.RemoveOverlay<EntityRotationOverlay>();
-                }
+            if (value && !_overlayManager.HasOverlay<EntityRotationOverlay>())
+            {
+                _overlayManager.AddOverlay(new EntityRotationOverlay(_lookup, _transform));
+            }
+            else
+            {
+                _overlayManager.RemoveOverlay<EntityRotationOverlay>();
             }
         }
+    }
 
-        private sealed class EntityPositionOverlay : Overlay
+    /// <summary>
+    /// Toggles the visual overlay of the local velocity for each entity on screen.
+    /// </summary>
+    public bool DebugVelocities
+    {
+        get => _debugVelocities;
+        set
         {
-            private readonly EntityLookupSystem _lookup;
-            private readonly IEntityManager _entityManager;
-            private readonly SharedTransformSystem _transform;
-
-            public override OverlaySpace Space => OverlaySpace.WorldSpace;
-
-            public EntityPositionOverlay(EntityLookupSystem lookup, IEntityManager entityManager, SharedTransformSystem transform)
+            if (value == DebugVelocities)
             {
-                _lookup = lookup;
-                _entityManager = entityManager;
-                _transform = transform;
+                return;
             }
 
-            protected internal override void Draw(in OverlayDrawArgs args)
+            _debugVelocities = value;
+
+            if (value && !_overlayManager.HasOverlay<EntityVelocityOverlay>())
             {
-                const float stubLength = 0.25f;
-
-                var worldHandle = (DrawingHandleWorld) args.DrawingHandle;
-
-                foreach (var entity in _lookup.GetEntitiesIntersecting(args.MapId, args.WorldBounds))
-                {
-                    var (center, worldRotation) = _transform.GetWorldPositionRotation(entity);
-
-                    var xLine = worldRotation.RotateVec(Vector2.UnitX);
-                    var yLine = worldRotation.RotateVec(Vector2.UnitY);
-
-                    worldHandle.DrawLine(center, center + xLine * stubLength, Color.Red);
-                    worldHandle.DrawLine(center, center + yLine * stubLength, Color.Green);
-                }
+                _overlayManager.AddOverlay(new EntityVelocityOverlay(EntityManager, _lookup, _transform));
+            }
+            else
+            {
+                _overlayManager.RemoveOverlay<EntityVelocityOverlay>();
             }
         }
+    }
 
-        private sealed class EntityRotationOverlay : Overlay
+    /// <summary>
+    /// Toggles the visual overlay of the angular velocity for each entity on screen.
+    /// </summary>
+    public bool DebugAngularVelocities
+    {
+        get => _debugAngularVelocities;
+        set
         {
-            private readonly EntityLookupSystem _lookup;
-            private readonly IEntityManager _entityManager;
-
-            public override OverlaySpace Space => OverlaySpace.WorldSpace;
-
-            public EntityRotationOverlay(EntityLookupSystem lookup, IEntityManager entityManager)
+            if (value == DebugAngularVelocities)
             {
-                _lookup = lookup;
-                _entityManager = entityManager;
+                return;
             }
 
-            protected internal override void Draw(in OverlayDrawArgs args)
+            _debugAngularVelocities = value;
+
+            if (value && !_overlayManager.HasOverlay<EntityAngularVelocityOverlay>())
             {
-                const float stubLength = 0.25f;
-                var worldHandle = (DrawingHandleWorld) args.DrawingHandle;
-                var xformQuery = _entityManager.GetEntityQuery<TransformComponent>();
+                _overlayManager.AddOverlay(new EntityAngularVelocityOverlay(EntityManager, _lookup, _transform));
+            }
+            else
+            {
+                _overlayManager.RemoveOverlay<EntityAngularVelocityOverlay>();
+            }
+        }
+    }
+    private sealed class EntityPositionOverlay(EntityLookupSystem _lookup, SharedTransformSystem _transform) : Overlay
+    {
+        public override OverlaySpace Space => OverlaySpace.WorldSpace;
 
-                foreach (var entity in _lookup.GetEntitiesIntersecting(args.MapId, args.WorldBounds))
-                {
-                    var (center, worldRotation) = xformQuery.GetComponent(entity).GetWorldPositionRotation();
+        protected internal override void Draw(in OverlayDrawArgs args)
+        {
+            const float stubLength = 0.25f;
 
-                    var drawLine = worldRotation.RotateVec(-Vector2.UnitY);
+            var worldHandle = (DrawingHandleWorld) args.DrawingHandle;
 
-                    worldHandle.DrawLine(center, center + drawLine * stubLength, Color.Red);
-                }
+            foreach (var uid in _lookup.GetEntitiesIntersecting(args.MapId, args.WorldBounds))
+            {
+                var (center, worldRotation) = _transform.GetWorldPositionRotation(uid);
+
+                var xLine = worldRotation.RotateVec(Vector2.UnitX);
+                var yLine = worldRotation.RotateVec(Vector2.UnitY);
+
+                worldHandle.DrawLine(center, center + xLine * stubLength, Color.Red);
+                worldHandle.DrawLine(center, center + yLine * stubLength, Color.Green);
+            }
+        }
+    }
+
+    private sealed class EntityRotationOverlay(EntityLookupSystem _lookup, SharedTransformSystem _transform) : Overlay
+    {
+        public override OverlaySpace Space => OverlaySpace.WorldSpace;
+
+        protected internal override void Draw(in OverlayDrawArgs args)
+        {
+            const float stubLength = 0.25f;
+            var worldHandle = (DrawingHandleWorld) args.DrawingHandle;
+
+            foreach (var uid in _lookup.GetEntitiesIntersecting(args.MapId, args.WorldBounds))
+            {
+                var (center, worldRotation) = _transform.GetWorldPositionRotation(uid);
+
+                var drawLine = worldRotation.RotateVec(-Vector2.UnitY);
+
+                worldHandle.DrawLine(center, center + drawLine * stubLength, Color.Red);
+            }
+        }
+    }
+
+    private sealed class EntityVelocityOverlay(IEntityManager _entityManager, EntityLookupSystem _lookup, SharedTransformSystem _transform) : Overlay
+    {
+        public override OverlaySpace Space => OverlaySpace.WorldSpace;
+
+        protected internal override void Draw(in OverlayDrawArgs args)
+        {
+            const float multiplier = 0.2f;
+
+            var worldHandle = (DrawingHandleWorld) args.DrawingHandle;
+
+            var physicsQuery = _entityManager.GetEntityQuery<PhysicsComponent>();
+            foreach (var uid in _lookup.GetEntitiesIntersecting(args.MapId, args.WorldBounds))
+            {
+                if(!physicsQuery.TryGetComponent(uid, out var physicsComp))
+                    continue;
+
+                var center = _transform.GetWorldPosition(uid);
+                var localVelocity = physicsComp.LinearVelocity;
+
+                if (localVelocity != Vector2.Zero)
+                    worldHandle.DrawLine(center, center + localVelocity * multiplier, Color.Yellow);
+            }
+        }
+    }
+
+    private sealed class EntityAngularVelocityOverlay(IEntityManager _entityManager, EntityLookupSystem _lookup, SharedTransformSystem _transform) : Overlay
+    {
+        public override OverlaySpace Space => OverlaySpace.WorldSpace;
+
+        protected internal override void Draw(in OverlayDrawArgs args)
+        {
+            const float multiplier = (float)(0.2 / (2 * System.Math.PI));
+
+            var worldHandle = (DrawingHandleWorld) args.DrawingHandle;
+
+            var physicsQuery = _entityManager.GetEntityQuery<PhysicsComponent>();
+            foreach (var uid in _lookup.GetEntitiesIntersecting(args.MapId, args.WorldBounds))
+            {
+                if(!physicsQuery.TryGetComponent(uid, out var physicsComp))
+                    continue;
+
+                var center = _transform.GetWorldPosition(uid);
+                var angularVelocity = physicsComp.AngularVelocity;
+
+                if (angularVelocity != 0.0f)
+                    worldHandle.DrawCircle(center, angularVelocity * multiplier, angularVelocity > 0 ? Color.Magenta : Color.Blue, false);
             }
         }
     }
 }
+

Robust.Client/Debugging/DebugPhysicsSystem.cs

@@ -413,8 +413,9 @@ namespace Robust.Client.Debugging
                     }
 
                     var body = bodyEnt.Comp;
+                    var meta = _entityManager.GetComponent<MetaDataComponent>(bodyEnt);
 
-                    screenHandle.DrawString(_font, drawPos + new Vector2(0, row * lineHeight), $"Ent: {bodyEnt.Owner}");
+                    screenHandle.DrawString(_font, drawPos + new Vector2(0, row * lineHeight), $"Ent: {bodyEnt.Owner} ({meta.EntityName})");
                     row++;
                     screenHandle.DrawString(_font, drawPos + new Vector2(0, row * lineHeight), $"Layer: {Convert.ToString(body.CollisionLayer, 2)}");
                     row++;

Robust.Client/GameController/GameController.cs

@@ -384,7 +384,7 @@ namespace Robust.Client
 
             _prof.Initialize();
 
-            _resManager.Initialize(Options.LoadConfigAndUserData ? userDataDir : null);
+            _resManager.Initialize(Options.LoadConfigAndUserData ? userDataDir : null, hideUserDataDir: true);
 
             var mountOptions = _commandLineArgs != null
                 ? MountOptions.Merge(_commandLineArgs.MountOptions, Options.MountOptions)

Robust.Client/GameObjects/ClientEntityManager.cs

@@ -117,7 +117,7 @@ namespace Robust.Client.GameObjects
                 base.DirtyField(uid, comp, fieldName, metadata);
         }
 
-        public override void DirtyFields<T>(EntityUid uid, T comp, MetaDataComponent? meta, params ReadOnlySpan<string> fields)
+        public override void DirtyFields<T>(EntityUid uid, T comp, MetaDataComponent? meta, params string[] fields)
         {
             // TODO Prediction
             // does the client actually need to dirty the field?

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

@@ -30,6 +30,7 @@ using DrawDepthTag = Robust.Shared.GameObjects.DrawDepth;
 using static Robust.Shared.Serialization.TypeSerializers.Implementations.SpriteSpecifierSerializer;
 using Direction = Robust.Shared.Maths.Direction;
 using Vector4 = Robust.Shared.Maths.Vector4;
+using SysVec4 = System.Numerics.Vector4;
 
 namespace Robust.Client.GameObjects
 {
@@ -753,12 +754,20 @@ namespace Robust.Client.GameObjects
                 if (layerDatum.Shader == string.Empty)
                 {
                     layer.ShaderPrototype = null;
+                    layer.UnShaded = false;
+                    layer.Shader = null;
+                }
+                else if (layerDatum.Shader == SpriteSystem.UnshadedId.Id)
+                {
+                    layer.ShaderPrototype = SpriteSystem.UnshadedId;
+                    layer.UnShaded = true;
                     layer.Shader = null;
                 }
                 else if (prototypes.TryIndex<ShaderPrototype>(layerDatum.Shader, out var prototype))
                 {
                     layer.ShaderPrototype = layerDatum.Shader;
                     layer.Shader = prototype.Instance();
+                    layer.UnShaded = false;
                 }
                 else
                 {
@@ -835,11 +844,28 @@ namespace Robust.Client.GameObjects
             if (!TryGetLayer(layer, out var theLayer, true))
                 return;
 
+            if (shader == null)
+            {
+                theLayer.UnShaded = false;
+                theLayer.Shader = null;
+                theLayer.ShaderPrototype = null;
+                return;
+            }
+
+            if (prototype == SpriteSystem.UnshadedId.Id)
+            {
+                theLayer.UnShaded = true;
+                theLayer.ShaderPrototype = SpriteSystem.UnshadedId;
+                theLayer.Shader = null;
+                return;
+            }
+
+            theLayer.UnShaded = false;
             theLayer.Shader = shader;
             theLayer.ShaderPrototype = prototype;
         }
 
-        public void LayerSetShader(object layerKey, ShaderInstance shader, string? prototype = null)
+        public void LayerSetShader(object layerKey, ShaderInstance? shader, string? prototype = null)
         {
             if (!LayerMapTryGet(layerKey, out var layer, true))
                 return;
@@ -1493,10 +1519,18 @@ namespace Robust.Client.GameObjects
         {
             [ViewVariables] private readonly SpriteComponent _parent;
 
-            [ViewVariables] public string? ShaderPrototype;
+            [ViewVariables] public ProtoId<ShaderPrototype>? ShaderPrototype;
             [ViewVariables] public ShaderInstance? Shader;
             [ViewVariables] public Texture? Texture;
 
+            /// <summary>
+            /// If true, then this layer is drawn without lighting applied.
+            /// Unshaded layers are given special treatment and don't just use the unshaded-shader to avoid having to
+            /// unnecessarily swap out the light texture. This helps the number of batches that need to be sent to the
+            /// GPU while drawing sprites.
+            /// </summary>
+            [ViewVariables] internal bool UnShaded;
+
             private RSI? _rsi;
             [ViewVariables] public RSI? RSI
             {
@@ -1663,6 +1697,7 @@ namespace Robust.Client.GameObjects
                 if (toClone.Shader != null)
                 {
                     Shader = toClone.Shader.Mutable ? toClone.Shader.Duplicate() : toClone.Shader;
+                    UnShaded = toClone.UnShaded;
                     ShaderPrototype = toClone.ShaderPrototype;
                 }
                 Texture = toClone.Texture;
@@ -2078,6 +2113,20 @@ namespace Robust.Client.GameObjects
                     drawingHandle.UseShader(Shader);
 
                 var layerColor = _parent.color * Color;
+
+                DebugTools.Assert(layerColor is {R: >= 0, G: >= 0, B: >= 0, A: >= 0}, "Negative colour modulation");
+
+                if (UnShaded)
+                {
+                    DebugTools.AssertNull(Shader);
+
+                    // Negative modulation values are used to disable light shading in the default shader.
+                    // Specifically we set colour = -1 - colour
+                    // This ensures that non-negative values become negative & is trivially invertible.
+                    // Alternatively we could just clamp the colour to [0,1] and subtract a constant.
+                    layerColor = new(new SysVec4(-1) - layerColor.RGBA);
+                }
+
                 var textureSize = texture.Size / (float)EyeManager.PixelsPerMeter;
                 var quad = Box2.FromDimensions(textureSize/-2, textureSize);
 

Robust.Client/GameObjects/EntitySystems/AnimationPlayerSystem.cs

@@ -76,7 +76,7 @@ namespace Robust.Client.GameObjects
             foreach (var key in remie)
             {
                 component.PlayingAnimations.Remove(key);
-                var completedEvent = new AnimationCompletedEvent {Uid = uid, Key = key, Finished = true};
+                var completedEvent = new AnimationCompletedEvent(uid, component, key, true);
                 EntityManager.EventBus.RaiseLocalEvent(uid, completedEvent, true);
             }
 
@@ -187,7 +187,7 @@ namespace Robust.Client.GameObjects
                 return;
             }
 
-            var completedEvent = new AnimationCompletedEvent {Uid = entity.Owner, Key = key, Finished = false};
+            var completedEvent = new AnimationCompletedEvent(entity.Owner, entity.Comp, key, false);
             EntityManager.EventBus.RaiseLocalEvent(entity.Owner, completedEvent, true);
         }
 
@@ -202,13 +202,33 @@ namespace Robust.Client.GameObjects
     /// </summary>
     public sealed class AnimationCompletedEvent : EntityEventArgs
     {
+        /// <summary>
+        /// The entity associated with the event.
+        /// </summary>
         public EntityUid Uid { get; init; }
+
+        /// <summary>
+        /// The animation player component associated with the entity this event was raised on.
+        /// </summary>
+        public AnimationPlayerComponent AnimationPlayer { get; init; }
+
+        /// <summary>
+        /// The key associated with the animation that was completed.
+        /// </summary>
         public string Key { get; init; } = string.Empty;
 
         /// <summary>
         /// If true, the animation finished by getting to its natural end.
-        /// If false, it was removed prematurely via <see cref="AnimationPlayerSystem.Stop(Robust.Client.GameObjects.AnimationPlayerComponent,string)"/> or similar overloads.
+        /// If false, it was removed prematurely via <see cref="AnimationPlayerSystem.Stop(EntityUid,AnimationPlayerComponent,string)"/> or similar overloads.
         /// </summary>
         public bool Finished { get; init; }
+
+        public AnimationCompletedEvent(EntityUid uid, AnimationPlayerComponent animationPlayer, string key, bool finished = true)
+        {
+            Uid = uid;
+            AnimationPlayer = animationPlayer;
+            Key = key;
+            Finished = finished;
+        }
     }
 }

Robust.Client/GameObjects/EntitySystems/MapSystem.cs

@@ -9,10 +9,6 @@ namespace Robust.Client.GameObjects;
 
 public sealed class MapSystem : SharedMapSystem
 {
-    [Dependency] private readonly IOverlayManager _overlayManager = default!;
-    [Dependency] private readonly IResourceCache _resource = default!;
-    [Dependency] private readonly ITileDefinitionManager _tileDefinitionManager = default!;
-
     protected override MapId GetNextMapId()
     {
         // Client-side map entities use negative map Ids to avoid conflict with server-side maps.
@@ -23,16 +19,4 @@ public sealed class MapSystem : SharedMapSystem
         }
         return id;
     }
-
-    public override void Initialize()
-    {
-        base.Initialize();
-        _overlayManager.AddOverlay(new TileEdgeOverlay(EntityManager, _resource, _tileDefinitionManager));
-    }
-
-    public override void Shutdown()
-    {
-        base.Shutdown();
-        _overlayManager.RemoveOverlay<TileEdgeOverlay>();
-    }
 }

Robust.Client/GameObjects/EntitySystems/ShowPlayerVelocityDebugSystem.cs

@@ -0,0 +1,66 @@
+using System.Numerics;
+using Robust.Client.Graphics;
+using Robust.Client.Player;
+using Robust.Client.UserInterface;
+using Robust.Client.UserInterface.Controls;
+using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.Physics.Components;
+
+namespace Robust.Client.GameObjects;
+
+public sealed class ShowPlayerVelocityDebugSystem : EntitySystem
+{
+    [Dependency] private readonly IEyeManager _eyeManager = default!;
+    [Dependency] private readonly IPlayerManager _playerManager = default!;
+    [Dependency] private readonly TransformSystem _transform = default!;
+    [Dependency] private readonly IUserInterfaceManager _uiManager = default!;
+
+    internal bool Enabled
+    {
+        get => _label.Parent != null;
+        set
+        {
+            if (value)
+            {
+                _uiManager.WindowRoot.AddChild(_label);
+            }
+            else
+            {
+                _label.Orphan();
+            }
+        }
+    }
+
+    private Label _label = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+        _label = new Label();
+    }
+
+    public override void FrameUpdate(float frameTime)
+    {
+        base.FrameUpdate(frameTime);
+        if (!Enabled)
+        {
+            _label.Visible = false;
+            return;
+        }
+
+        var player = _playerManager.LocalEntity;
+
+        if (player == null || !EntityManager.TryGetComponent(player.Value, out PhysicsComponent? body))
+        {
+            _label.Visible = false;
+            return;
+        }
+
+        var screenPos = _eyeManager.WorldToScreen(_transform.GetWorldPosition(Transform(player.Value)));
+        LayoutContainer.SetPosition(_label, screenPos + new Vector2(0, 50));
+        _label.Visible = true;
+
+        _label.Text = $"Speed: {body.LinearVelocity.Length():0.00}\nLinear: {body.LinearVelocity.X:0.00}, {body.LinearVelocity.Y:0.00}\nAngular: {body.AngularVelocity}";
+    }
+}

Robust.Client/GameObjects/EntitySystems/SpriteSystem.cs

@@ -37,6 +37,7 @@ namespace Robust.Client.GameObjects
         [Dependency] private readonly ILogManager _logManager = default!;
         [Dependency] private readonly SharedTransformSystem _xforms = default!;
 
+        public static readonly ProtoId<ShaderPrototype> UnshadedId = "unshaded";
         private readonly Queue<SpriteComponent> _inertUpdateQueue = new();
 
         /// <summary>

Robust.Client/GameObjects/EntitySystems/VelocityDebugSystem.cs

@@ -1,54 +0,0 @@
-using System.Numerics;
-using Robust.Client.Graphics;
-using Robust.Client.Player;
-using Robust.Client.UserInterface;
-using Robust.Client.UserInterface.Controls;
-using Robust.Shared.GameObjects;
-using Robust.Shared.IoC;
-using Robust.Shared.Maths;
-using Robust.Shared.Physics.Components;
-
-namespace Robust.Client.GameObjects
-{
-    public sealed class VelocityDebugSystem : EntitySystem
-    {
-        [Dependency] private readonly IEyeManager _eyeManager = default!;
-        [Dependency] private readonly IPlayerManager _playerManager = default!;
-        [Dependency] private readonly TransformSystem _transform = default!;
-
-        internal bool Enabled { get; set; }
-
-        private Label _label = default!;
-
-        public override void Initialize()
-        {
-            base.Initialize();
-            _label = new Label();
-            IoCManager.Resolve<IUserInterfaceManager>().StateRoot.AddChild(_label);
-        }
-
-        public override void FrameUpdate(float frameTime)
-        {
-            base.FrameUpdate(frameTime);
-            if (!Enabled)
-            {
-                _label.Visible = false;
-                return;
-            }
-
-            var player = _playerManager.LocalEntity;
-
-            if (player == null || !EntityManager.TryGetComponent(player.Value, out PhysicsComponent? body))
-            {
-                _label.Visible = false;
-                return;
-            }
-
-            var screenPos = _eyeManager.WorldToScreen(_transform.GetWorldPosition(Transform(player.Value)));
-            LayoutContainer.SetPosition(_label, screenPos + new Vector2(0, 50));
-            _label.Visible = true;
-
-            _label.Text = $"Speed: {body.LinearVelocity.Length():0.00}\nLinear: {body.LinearVelocity.X:0.00}, {body.LinearVelocity.Y:0.00}\nAngular: {body.AngularVelocity}";
-        }
-    }
-}

Robust.Client/GameStates/ClientGameStateManager.cs

@@ -384,7 +384,6 @@ namespace Robust.Client.GameStates
                     _processor.UpdateFullRep(curState);
                 }
 
-                IEnumerable<NetEntity> createdEntities;
                 using (_prof.Group("ApplyGameState"))
                 {
                     if (_timing.LastProcessedTick < targetProcessedTick && nextState != null)
@@ -699,8 +698,9 @@ namespace Robust.Client.GameStates
 
 #if !EXCEPTION_TOLERANCE
                     throw new KeyNotFoundException();
-#endif
+#else
                     continue;
+#endif
                 }
 
                 var compData = _compDataPool.Get();
@@ -961,8 +961,9 @@ namespace Robust.Client.GameStates
                 RequestFullState();
 #if !EXCEPTION_TOLERANCE
                 throw;
-#endif
+#else
                 return;
+#endif
             }
 
             if (data.Created)
@@ -980,8 +981,9 @@ namespace Robust.Client.GameStates
                     RequestFullState();
 #if !EXCEPTION_TOLERANCE
                     throw;
-#endif
+#else
                     return;
+#endif
                 }
             }
 

Robust.Client/Graphics/Clyde/Clyde.Constants.cs

@@ -21,7 +21,7 @@ namespace Robust.Client.Graphics.Clyde
         private const string UniModelMatrix = "modelMatrix";
         private const string UniTexturePixelSize = "TEXTURE_PIXEL_SIZE";
         private const string UniMainTexture = "TEXTURE";
-        private const string UniLightTexture = "lightMap";
+        private const string UniLightTexture = "lightMap"; // TODO CLYDE consistent shader variable naming
         private const string UniProjViewMatrices = "projectionViewMatrices";
         private const string UniUniformConstants = "uniformConstants";
 

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

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenToolkit.Graphics.OpenGL4;
+using Robust.Client.ResourceManagement;
 using Robust.Shared.Enums;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Graphics;
@@ -22,6 +23,9 @@ namespace Robust.Client.Graphics.Clyde
         /// </summary>
         private HashSet<Type> _erroredGridOverlays = new();
 
+        private Vertex2D[]? _chunkMeshBuilderVertexBuffer;
+        private ushort[]? _chunkMeshBuilderIndexBuffer;
+
         private int _verticesPerChunk(MapChunk chunk) => chunk.ChunkSize * chunk.ChunkSize * 4;
         private int _indicesPerChunk(MapChunk chunk) => chunk.ChunkSize * chunk.ChunkSize * GetQuadBatchIndexCount();
 
@@ -63,29 +67,78 @@ namespace Robust.Client.Graphics.Clyde
                     gridProgram.SetUniform(UniIModUV, new Vector4(0, 0, 1, 1));
                 }
 
-                var transform = _entityManager.GetComponent<TransformComponent>(mapGrid);
-                gridProgram.SetUniform(UniIModelMatrix, _transformSystem.GetWorldMatrix(transform));
+                gridProgram.SetUniform(UniIModelMatrix, _transformSystem.GetWorldMatrix(mapGrid));
                 var enumerator = mapSystem.GetMapChunks(mapGrid.Owner, mapGrid.Comp, worldBounds);
 
+                // Handle base texture updates.
                 while (enumerator.MoveNext(out var chunk))
                 {
                     DebugTools.Assert(chunk.FilledTiles > 0);
-                    if (!data.TryGetValue(chunk.Indices, out MapChunkData? datum))
-                        data[chunk.Indices] = datum = _initChunkBuffers(mapGrid, chunk);
+                    var datum = EnsureChunkInitialized(data, chunk, mapGrid);
 
-                    if (datum.Dirty)
-                        _updateChunkMesh(mapGrid, chunk, datum);
-
-                    DebugTools.Assert(datum.TileCount > 0);
-                    if (datum.TileCount == 0)
+                    if (!datum.Dirty)
                         continue;
 
-                    BindVertexArray(datum.VAO);
-                    CheckGlError();
+                    _updateChunkMesh(mapGrid, chunk, datum);
+
+                    // Dirty edge tiles for next step.
+                    datum.EdgeDirty = true;
+
+                    for (var x = -1; x <= 1; x++)
+                    {
+                        for (var y = -1; y <= 1; y++)
+                        {
+                            var neighbor = chunk.Indices + new Vector2i(x, y);
+
+                            if (!mapGrid.Comp.Chunks.TryGetValue(neighbor, out var neighborChunk))
+                                continue;
+
+                            var neighborDatum = EnsureChunkInitialized(data, neighborChunk, mapGrid);
+                            neighborDatum.EdgeDirty = true;
+                        }
+                    }
+                }
+
+                enumerator = mapSystem.GetMapChunks(mapGrid.Owner, mapGrid.Comp, worldBounds);
+
+                // Handle edge sprites.
+                while (enumerator.MoveNext(out var chunk))
+                {
+                    var datum = data[chunk.Indices];
+
+                    if (!datum.EdgeDirty)
+                        continue;
+
+                    _updateChunkEdges(mapGrid, chunk, datum);
+                }
+
+                enumerator = mapSystem.GetMapChunks(mapGrid.Owner, mapGrid.Comp, worldBounds);
+
+                // Draw chunks
+                while (enumerator.MoveNext(out var chunk))
+                {
+                    var datum = data[chunk.Indices];
+                    DebugTools.Assert(datum.TileCount > 0);
+                    if (datum.TileCount > 0)
+                    {
+                        BindVertexArray(datum.VAO);
+                        CheckGlError();
+
+                        _debugStats.LastGLDrawCalls += 1;
+                        GL.DrawElements(GetQuadGLPrimitiveType(), datum.TileCount * GetQuadBatchIndexCount(), DrawElementsType.UnsignedShort, 0);
+                        CheckGlError();
+                    }
+
+                    if (datum.EdgeCount > 0)
+                    {
+                        BindVertexArray(datum.EdgeVAO);
+                        CheckGlError();
+
+                        _debugStats.LastGLDrawCalls += 1;
+                        GL.DrawElements(GetQuadGLPrimitiveType(), datum.EdgeCount * GetQuadBatchIndexCount(), DrawElementsType.UnsignedShort, 0);
+                        CheckGlError();
+                    }
 
-                    _debugStats.LastGLDrawCalls += 1;
-                    GL.DrawElements(GetQuadGLPrimitiveType(), datum.TileCount * GetQuadBatchIndexCount(), DrawElementsType.UnsignedShort, 0);
-                    CheckGlError();
                 }
 
                 requiresFlush = false;
@@ -117,6 +170,17 @@ namespace Robust.Client.Graphics.Clyde
             CullEmptyChunks();
         }
 
+        private MapChunkData EnsureChunkInitialized(Dictionary<Vector2i, MapChunkData> data, MapChunk chunk, Entity<MapGridComponent> mapGrid)
+        {
+            if (!data.TryGetValue(chunk.Indices, out var datum))
+            {
+                data[chunk.Indices] = datum = new MapChunkData();
+                _initChunkBuffers(mapGrid, chunk, datum);
+            }
+
+            return datum;
+        }
+
         private void CullEmptyChunks()
         {
             foreach (var (grid, chunks) in _mapChunkData)
@@ -138,66 +202,141 @@ namespace Robust.Client.Graphics.Clyde
 
         private void _updateChunkMesh(Entity<MapGridComponent> grid, MapChunk chunk, MapChunkData datum)
         {
-            Span<ushort> indexBuffer = stackalloc ushort[_indicesPerChunk(chunk)];
-            Span<Vertex2D> vertexBuffer = stackalloc Vertex2D[_verticesPerChunk(chunk)];
+            Span<ushort> indexBuffer = EnsureSize(ref _chunkMeshBuilderIndexBuffer, _indicesPerChunk(chunk));
+            Span<Vertex2D> vertexBuffer = EnsureSize(ref _chunkMeshBuilderVertexBuffer, _verticesPerChunk(chunk));
 
             var i = 0;
-            var cSz = grid.Comp.ChunkSize;
-            var cScaled = chunk.Indices * cSz;
-            for (ushort x = 0; x < cSz; x++)
+            var chunkSize = grid.Comp.ChunkSize;
+            var chunkOriginScaled = chunk.Indices * chunkSize;
+
+            for (ushort x = 0; x < chunkSize; x++)
             {
-                for (ushort y = 0; y < cSz; y++)
+                for (ushort y = 0; y < chunkSize; y++)
                 {
+                    var gridX = x + chunkOriginScaled.X;
+                    var gridY = y + chunkOriginScaled.Y;
                     var tile = chunk.GetTile(x, y);
-                    if (tile.IsEmpty)
-                        continue;
 
-                    var regionMaybe = _tileDefinitionManager.TileAtlasRegion(tile);
-
-                    Box2 region;
-                    if (regionMaybe == null || regionMaybe.Length <= tile.Variant)
+                    // Tile render
+                    if (x != chunkSize && y != chunkSize)
                     {
-                        region = _tileDefinitionManager.ErrorTileRegion;
-                    }
-                    else
-                    {
-                        region = regionMaybe[tile.Variant];
-                    }
+                        // ReSharper disable once IntVariableOverflowInUncheckedContext
+                        if (tile.IsEmpty)
+                            continue;
 
-                    var gx = x + cScaled.X;
-                    var gy = y + cScaled.Y;
+                        var regionMaybe = _tileDefinitionManager.TileAtlasRegion(tile);
 
-                    var vIdx = i * 4;
-                    vertexBuffer[vIdx + 0] = new Vertex2D(gx, gy, region.Left, region.Bottom, Color.White);
-                    vertexBuffer[vIdx + 1] = new Vertex2D(gx + 1, gy, region.Right, region.Bottom, Color.White);
-                    vertexBuffer[vIdx + 2] = new Vertex2D(gx + 1, gy + 1, region.Right, region.Top, Color.White);
-                    vertexBuffer[vIdx + 3] = new Vertex2D(gx, gy + 1, region.Left, region.Top, Color.White);
-                    var nIdx = i * GetQuadBatchIndexCount();
-                    var tIdx = (ushort)(i * 4);
-                    QuadBatchIndexWrite(indexBuffer, ref nIdx, tIdx);
-                    i += 1;
+                        Box2 region;
+                        if (regionMaybe == null || regionMaybe.Length <= tile.Variant)
+                        {
+                            region = _tileDefinitionManager.ErrorTileRegion;
+                        }
+                        else
+                        {
+                            region = regionMaybe[tile.Variant];
+                        }
+
+                        WriteTileToBuffers(i, gridX, gridY, vertexBuffer, indexBuffer, region);
+                        i += 1;
+                    }
                 }
             }
 
+            var indexSlice = indexBuffer[..(i * GetQuadBatchIndexCount())];
+            var vertSlice = vertexBuffer[..(i * 4)];
+
             GL.BindVertexArray(datum.VAO);
             CheckGlError();
             datum.EBO.Use();
             datum.VBO.Use();
-            datum.EBO.Reallocate(indexBuffer[..(i * GetQuadBatchIndexCount())]);
-            datum.VBO.Reallocate(vertexBuffer[..(i * 4)]);
-            datum.Dirty = false;
+            datum.EBO.Reallocate(indexSlice);
+            datum.VBO.Reallocate(vertSlice);
+
             datum.TileCount = i;
+            datum.Dirty = false;
         }
 
-        private unsafe MapChunkData _initChunkBuffers(Entity<MapGridComponent> grid, MapChunk chunk)
+        private void _updateChunkEdges(Entity<MapGridComponent> grid, MapChunk chunk, MapChunkData datum)
         {
+            // Need a buffer that can potentially store all neighbor tiles
+            Span<ushort> indexBuffer = EnsureSize(ref _chunkMeshBuilderIndexBuffer, _indicesPerChunk(chunk) * 8);
+            Span<Vertex2D> vertexBuffer = EnsureSize(ref _chunkMeshBuilderVertexBuffer, _verticesPerChunk(chunk) * 8);
+
+            var i = 0;
+            var chunkSize = grid.Comp.ChunkSize;
+            var chunkOriginScaled = chunk.Indices * chunkSize;
+            var maps = _entityManager.System<SharedMapSystem>();
+
+            for (ushort x = 0; x < chunkSize; x++)
+            {
+                for (ushort y = 0; y < chunkSize; y++)
+                {
+                    var gridX = x + chunkOriginScaled.X;
+                    var gridY = y + chunkOriginScaled.Y;
+                    var tile = chunk.GetTile(x, y);
+                    var tileDef = _tileDefinitionManager[tile.TypeId];
+
+                    // Edge render
+                    for (var nx = -1; nx <= 1; nx++)
+                    {
+                        for (var ny = -1; ny <= 1; ny++)
+                        {
+                            if (nx == 0 && ny == 0)
+                                continue;
+
+                            var neighborIndices = new Vector2i(gridX + nx, gridY + ny);
+                            if (!maps.TryGetTile(grid.Comp, neighborIndices, out var neighborTile))
+                                continue;
+
+                            var neighborDef = _tileDefinitionManager[neighborTile.TypeId];
+
+                            // If it's the same tile then no edge to be drawn.
+                            if (tile.TypeId == neighborTile.TypeId || neighborDef.EdgeSprites.Count == 0)
+                                continue;
+
+                            // If neighbor is a lower priority then us then don't draw on our tile.
+                            if (neighborDef.EdgeSpritePriority < tileDef.EdgeSpritePriority)
+                                continue;
+
+                            var direction = new Vector2i(nx, ny).AsDirection().GetOpposite();
+                            var regionMaybe = _tileDefinitionManager.TileAtlasRegion(neighborTile.TypeId, direction);
+
+                            if (regionMaybe == null)
+                                continue;
+
+                            var region = regionMaybe[0];
+                            WriteTileToBuffers(i, gridX, gridY, vertexBuffer, indexBuffer, region);
+                            i += 1;
+                        }
+                    }
+                }
+            }
+
+            // We don't save the edge buffers back because we might need to re-use it if a neighbor chunk updates.
+            var indexSlice = indexBuffer[..(i * GetQuadBatchIndexCount())];
+            var vertSlice = vertexBuffer[..(i * 4)];
+
+            GL.BindVertexArray(datum.EdgeVAO);
+            CheckGlError();
+            datum.EdgeEBO.Use();
+            datum.EdgeVBO.Use();
+            datum.EdgeEBO.Reallocate(indexSlice);
+            datum.EdgeVBO.Reallocate(vertSlice);
+
+            datum.EdgeCount = i;
+            datum.EdgeDirty = false;
+        }
+
+        private unsafe void _initChunkBuffers(Entity<MapGridComponent> grid, MapChunk chunk, MapChunkData datum)
+        {
+            var vboSize = _verticesPerChunk(chunk) * sizeof(Vertex2D);
+            var eboSize = _indicesPerChunk(chunk) * sizeof(ushort);
+
+            // Base VAO
             var vao = GenVertexArray();
             BindVertexArray(vao);
             CheckGlError();
 
-            var vboSize = _verticesPerChunk(chunk) * sizeof(Vertex2D);
-            var eboSize = _indicesPerChunk(chunk) * sizeof(ushort);
-
             var vbo = new GLBuffer(this, BufferTarget.ArrayBuffer, BufferUsageHint.DynamicDraw,
                 vboSize, $"Grid {grid.Owner} chunk {chunk.Indices} VBO");
             var ebo = new GLBuffer(this, BufferTarget.ElementArrayBuffer, BufferUsageHint.DynamicDraw,
@@ -212,12 +351,30 @@ namespace Robust.Client.Graphics.Clyde
             vbo.Use();
             ebo.Use();
 
-            var datum = new MapChunkData(vao, vbo, ebo)
-            {
-                Dirty = true
-            };
+            datum.EBO = ebo;
+            datum.VBO = vbo;
+            datum.VAO = vao;
 
-            return datum;
+            // EdgeVAO
+            var edgeVao = GenVertexArray();
+            BindVertexArray(edgeVao);
+            CheckGlError();
+
+            var edgeVbo = new GLBuffer(this, BufferTarget.ArrayBuffer, BufferUsageHint.DynamicDraw,
+                vboSize * 8, $"Grid {grid.Owner} chunk {chunk.Indices} EdgeVBO");
+            var edgeEbo = new GLBuffer(this, BufferTarget.ElementArrayBuffer, BufferUsageHint.DynamicDraw,
+                eboSize * 8, $"Grid {grid.Owner} chunk {chunk.Indices} EdgeEBO");
+
+            ObjectLabelMaybe(ObjectLabelIdentifier.VertexArray, vao, $"Grid {grid.Owner} chunk {chunk.Indices} EdgeVAO");
+            SetupVAOLayout();
+            CheckGlError();
+
+            edgeVbo.Use();
+            edgeEbo.Use();
+
+            datum.EdgeEBO = edgeEbo;
+            datum.EdgeVBO = edgeVbo;
+            datum.EdgeVAO = edgeVao;
         }
 
         private void DeleteChunk(MapChunkData data)
@@ -254,19 +411,49 @@ namespace Robust.Client.Graphics.Clyde
             _mapChunkData.Remove(gridId);
         }
 
+        private static T[] EnsureSize<T>(ref T[]? field, int size)
+        {
+            if (field == null || field.Length < size)
+                field = new T[size];
+
+            return field;
+        }
+
+        private void WriteTileToBuffers(
+            int i,
+            int gridX,
+            int gridY,
+            Span<Vertex2D> vertexBuffer,
+            Span<ushort> indexBuffer,
+            Box2 region)
+        {
+            var vIdx = i * 4;
+            vertexBuffer[vIdx + 0] = new Vertex2D(gridX, gridY, region.Left, region.Bottom, Color.White);
+            vertexBuffer[vIdx + 1] = new Vertex2D(gridX + 1, gridY, region.Right, region.Bottom, Color.White);
+            vertexBuffer[vIdx + 2] = new Vertex2D(gridX + 1, gridY + 1, region.Right, region.Top, Color.White);
+            vertexBuffer[vIdx + 3] = new Vertex2D(gridX, gridY + 1, region.Left, region.Top, Color.White);
+            var nIdx = i * GetQuadBatchIndexCount();
+            var tIdx = (ushort)(i * 4);
+            QuadBatchIndexWrite(indexBuffer, ref nIdx, tIdx);
+        }
+
         private sealed class MapChunkData
         {
-            public bool Dirty;
-            public readonly uint VAO;
-            public readonly GLBuffer VBO;
-            public readonly GLBuffer EBO;
+            public bool EdgeDirty = true;
+            public bool Dirty = true;
+
+            public uint VAO;
+            public GLBuffer VBO = default!;
+            public GLBuffer EBO = default!;
             public int TileCount;
 
-            public MapChunkData(uint vao, GLBuffer vbo, GLBuffer ebo)
+            public uint EdgeVAO;
+            public GLBuffer EdgeVBO = default!;
+            public GLBuffer EdgeEBO = default!;
+            public int EdgeCount;
+
+            public MapChunkData()
             {
-                VAO = vao;
-                VBO = vbo;
-                EBO = ebo;
             }
         }
     }

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

@@ -98,9 +98,11 @@ namespace Robust.Client.Graphics.Clyde
         private LightCapacityComparer _lightCap = new();
         private ShadowCapacityComparer _shadowCap = new ShadowCapacityComparer();
 
+        private float _maxLightRadius;
+
         private unsafe void InitLighting()
         {
-
+            _cfg.OnValueChanged(CVars.MaxLightRadius, val => { _maxLightRadius = val;}, true);
 
             // Other...
             LoadLightingShaders();
@@ -617,8 +619,9 @@ namespace Robust.Client.Graphics.Clyde
             // Use worldbounds for this one as we only care if the light intersects our actual bounds
             var xforms = _entityManager.GetEntityQuery<TransformComponent>();
             var state = (this, count: 0, shadowCastingCount: 0, xforms, worldAABB);
+            var lightAabb = worldAABB.Enlarged(_maxLightRadius);
 
-            foreach (var (uid, comp) in _lightTreeSystem.GetIntersectingTrees(map, worldAABB))
+            foreach (var (uid, comp) in _lightTreeSystem.GetIntersectingTrees(map, lightAabb))
             {
                 var bounds = _transformSystem.GetInvWorldMatrix(uid, xforms).TransformBox(worldBounds);
                 comp.Tree.QueryAabb(ref state, LightQuery, bounds);

Robust.Client/Graphics/Clyde/Shaders/base-default.frag

@@ -1,8 +1,22 @@
+// UV coordinates in texture-space. I.e., (0,0) is the corner of the texture currently being used to draw.
+// When drawing a sprite from a texture atlas, (0,0) is the corner of the atlas, not the specific sprite being drawn.
 varying highp vec2 UV;
+
+// UV coordinates in quad-space. I.e., when drawing a sprite from a texture atlas (0,0) is the corner of the sprite
+// currently being drawn.
 varying highp vec2 UV2;
+
+// TBH I'm not sure what this is for. I think it is scree  UV coordiantes, i.e., FRAGCOORD.xy * SCREEN_PIXEL_SIZE ?
+// TODO CLYDE Is this still needed?
 varying highp vec2 Pos;
+
+// Vertex colour modulation. Note that negative values imply that the LIGHTMAP should be ignored. This is used to avoid
+// having to set the texture to a white/blank texture for sprites that have no light shading applied.
 varying highp vec4 VtxModulate;
 
+// The current light map. Unless disabled, this is automatically sampled to create the LIGHT vector, which is then used
+// to modulate the output colour.
+// TODO CLYDE consistent shader variable naming
 uniform sampler2D lightMap;
 
 // [SHADER_HEADER_CODE]
@@ -11,11 +25,37 @@ void main()
 {
     highp vec4 FRAGCOORD = gl_FragCoord;
 
+    // The output colour. This should get set by the shader code block.
+    // This will get modified by the LIGHT and MODULATE vectors.
     lowp vec4 COLOR;
 
-    lowp vec3 lightSample = texture2D(lightMap, Pos).rgb;
+    // The light colour, usually sampled from the LIGHTMAP
+    lowp vec4 LIGHT;
+
+    // Colour modulation vector.
+    highp vec4 MODULATE;
+
+    // Sample the texture outside of the branch / with uniform control flow.
+    LIGHT = texture2D(lightMap, Pos);
+
+    if (VtxModulate.x < 0.0)
+    {
+        // Negative VtxModulate implies unshaded/no lighting.
+        MODULATE = -1.0 - VtxModulate;
+        LIGHT = vec4(1.0);
+    }
+    else
+    {
+        MODULATE = VtxModulate;
+    }
+
+    // TODO CLYDE consistent shader variable naming
+    // Requires breaking changes.
+    lowp vec3 lightSample = LIGHT.xyz;
 
     // [SHADER_CODE]
 
-    gl_FragColor = zAdjustResult(COLOR * VtxModulate * vec4(lightSample, 1.0));
+    LIGHT.xyz = lightSample;
+
+    gl_FragColor = zAdjustResult(COLOR * MODULATE * LIGHT);
 }

Robust.Client/Graphics/Clyde/Shaders/base-default.vert

@@ -18,6 +18,7 @@ uniform mat3 modelMatrix;
 // Allows us to do texture atlassing with texture coordinates 0->1
 // Input texture coordinates get mapped to this range.
 uniform vec4 modifyUV;
+// TODO CLYDE Is this still needed?
 
 // [SHADER_HEADER_CODE]
 
@@ -39,5 +40,15 @@ void main()
     Pos = (VERTEX + 1.0) / 2.0;
     UV = mix(modifyUV.xy, modifyUV.zw, tCoord);
     UV2 = tCoord2;
-    VtxModulate = zFromSrgb(modulate);
+
+    // Negative modulation is being used as a hacky way to squeeze in lighting data.
+    // I.e., negative modulation implies we ignore the lighting.
+    if (modulate.x < 0.0)
+    {
+        VtxModulate = -1.0 - zFromSrgb(-1.0 - modulate);
+    }
+    else
+    {
+        VtxModulate = zFromSrgb(modulate);
+    }
 }

Robust.Client/Graphics/Clyde/Shaders/base-raw.frag

@@ -1,6 +1,7 @@
 varying highp vec2 UV;
 varying highp vec2 UV2;
 
+// TODO CLYDE consistent shader variable naming
 uniform sampler2D lightMap;
 
 // [SHADER_HEADER_CODE]

Robust.Client/Graphics/Shaders/ShaderPrototype.cs

@@ -16,7 +16,7 @@ using Vector4 = Robust.Shared.Maths.Vector4;
 
 namespace Robust.Client.Graphics
 {
-    [Prototype("shader")]
+    [Prototype]
     public sealed partial class ShaderPrototype : IPrototype, ISerializationHooks
     {
         [ViewVariables]

Robust.Client/Map/ClydeTileDefinitionManager.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Frozen;
 using System.Collections.Generic;
 using System.Linq;
 using Robust.Client.Graphics;
@@ -10,9 +11,11 @@ using Robust.Shared.Log;
 using Robust.Shared.Map;
 using Robust.Shared.Maths;
 using Robust.Shared.Prototypes;
+using Robust.Shared.Timing;
 using Robust.Shared.Utility;
 using SixLabors.ImageSharp;
 using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Processing;
 
 namespace Robust.Client.Map
 {
@@ -29,7 +32,7 @@ namespace Robust.Client.Map
 
         public Texture TileTextureAtlas => _tileTextureAtlas ?? Texture.Transparent;
 
-        private readonly Dictionary<int, Box2[]> _tileRegions = new();
+        private FrozenDictionary<(int Id, Direction Direction), Box2[]> _tileRegions = FrozenDictionary<(int Id, Direction Direction), Box2[]>.Empty;
 
         public Box2 ErrorTileRegion { get; private set; }
 
@@ -42,7 +45,14 @@ namespace Robust.Client.Map
         /// <inheritdoc />
         public Box2[]? TileAtlasRegion(int tileType)
         {
-            if (_tileRegions.TryGetValue(tileType, out var region))
+            return TileAtlasRegion(tileType, Direction.Invalid);
+        }
+
+        /// <inheritdoc />
+        public Box2[]? TileAtlasRegion(int tileType, Direction direction)
+        {
+            // ReSharper disable once CanSimplifyDictionaryTryGetValueWithGetValueOrDefault
+            if (_tileRegions.TryGetValue((tileType, direction), out var region))
             {
                 return region;
             }
@@ -83,7 +93,8 @@ namespace Robust.Client.Map
 
         internal void _genTextureAtlas()
         {
-            _tileRegions.Clear();
+            var sw = RStopwatch.StartNew();
+            var tileRegs = new Dictionary<(int Id, Direction Direction), Box2[]>();
             _tileTextureAtlas = null;
 
             var defList = TileDefs.Where(t => t.Sprite != null).ToList();
@@ -94,7 +105,7 @@ namespace Robust.Client.Map
 
             const int tileSize = EyeManager.PixelsPerMeter;
 
-            var tileCount = defList.Select(x => (int)x.Variants).Sum() + 1;
+            var tileCount = defList.Select(x => x.Variants + x.EdgeSprites.Count).Sum() + 1;
 
             var dimensionX = (int) Math.Ceiling(Math.Sqrt(tileCount));
             var dimensionY = (int) Math.Ceiling((float) tileCount / dimensionX);
@@ -102,11 +113,11 @@ namespace Robust.Client.Map
             var imgWidth = dimensionX * tileSize;
             var imgHeight = dimensionY * tileSize;
             var sheet = new Image<Rgba32>(imgWidth, imgHeight);
+            var w = (float) sheet.Width;
+            var h = (float) sheet.Height;
 
             // Add in the missing tile texture sprite as tile texture 0.
             {
-                var w = (float) sheet.Width;
-                var h = (float) sheet.Height;
                 ErrorTileRegion = Box2.FromDimensions(
                     0, (h - EyeManager.PixelsPerMeter) / h,
                     tileSize / w, tileSize / h);
@@ -154,25 +165,98 @@ namespace Robust.Client.Map
                     var box = new UIBox2i(0, 0, tileSize, tileSize).Translated(new Vector2i(j * tileSize, 0));
                     image.Blit(box, sheet, point);
 
-                    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);
-                    column++;
-
-                    if (column >= dimensionX)
-                    {
-                        column = 0;
-                        row++;
-                    }
+                    BumpColumn(ref row, ref column, dimensionX);
                 }
 
-                _tileRegions.Add(def.TileId, regionList);
+                tileRegs.Add((def.TileId, Direction.Invalid), regionList);
+
+                // Edges
+                if (def.EdgeSprites.Count <= 0)
+                    continue;
+
+                foreach (var direction in DirectionExtensions.AllDirections)
+                {
+                    if (!def.EdgeSprites.TryGetValue(direction, out var edge))
+                        continue;
+
+                    using (var stream = _manager.ContentFileRead(edge))
+                    {
+                        image = Image.Load<Rgba32>(stream);
+                    }
+
+                    if (image.Width != tileSize || image.Height != tileSize)
+                    {
+                        throw new NotSupportedException(
+                            $"Unable to load {path}, due to being unable to use tile textures with a dimension other than {tileSize}x{tileSize}.");
+                    }
+
+                    Angle angle = Angle.Zero;
+
+                    switch (direction)
+                    {
+                        // Corner sprites
+                        case Direction.SouthEast:
+                            break;
+                        case Direction.NorthEast:
+                            angle = new Angle(MathF.PI / 2f);
+                            break;
+                        case Direction.NorthWest:
+                            angle = new Angle(MathF.PI);
+                            break;
+                        case Direction.SouthWest:
+                            angle = new Angle(MathF.PI * 1.5f);
+                            break;
+                        // Edge sprites
+                        case Direction.South:
+                            break;
+                        case Direction.East:
+                            angle = new Angle(MathF.PI / 2f);
+                            break;
+                        case Direction.North:
+                            angle = new Angle(MathF.PI);
+                            break;
+                        case Direction.West:
+                            angle = new Angle(MathF.PI * 1.5f);
+                            break;
+                    }
+
+                    if (angle != Angle.Zero)
+                    {
+                        image.Mutate(o => o.Rotate((float)-angle.Degrees));
+                    }
+
+                    var point = new Vector2i(column * tileSize, row * tileSize);
+                    var box = new UIBox2i(0, 0, tileSize, tileSize);
+                    image.Blit(box, sheet, point);
+
+                    // If you ever need edge variants then you could just bump this.
+                    var edgeList = new Box2[1];
+                    edgeList[0] = Box2.FromDimensions(
+                        point.X / w, (h - point.Y - EyeManager.PixelsPerMeter) / h,
+                        tileSize / w, tileSize / h);
+
+                    tileRegs.Add((def.TileId, direction), edgeList);
+                    BumpColumn(ref row, ref column, dimensionX);
+                }
             }
 
+            _tileRegions = tileRegs.ToFrozenDictionary();
             _tileTextureAtlas = Texture.LoadFromImage(sheet, "Tile Atlas");
+            _sawmill.Debug($"Tile atlas took {sw.Elapsed} to build");
+        }
+
+        private void BumpColumn(ref int row, ref int column, int dimensionX)
+        {
+            column++;
+
+            if (column >= dimensionX)
+            {
+                column = 0;
+                row++;
+            }
         }
 
         void IPostInjectInit.PostInject()

Robust.Client/Map/IClydeTileDefinitionManager.cs

@@ -29,5 +29,12 @@ namespace Robust.Client.Map
         /// </summary>
         /// <returns>If null, do not draw the tile at all.</returns>
         Box2[]? TileAtlasRegion(int tileType);
+
+        /// <summary>
+        ///     Gets the region inside the texture atlas to use to draw a tile type.
+        ///     Also handles edge sprites.
+        /// </summary>
+        /// <returns>If null, do not draw the tile at all.</returns>
+        public Box2[]? TileAtlasRegion(int tileType, Direction direction);
     }
 }

Robust.Client/Map/TileEdgeOverlay.cs

@@ -1,125 +0,0 @@
-using System;
-using System.Numerics;
-using Robust.Client.Graphics;
-using Robust.Client.ResourceManagement;
-using Robust.Shared.GameObjects;
-using Robust.Shared.Map;
-using Robust.Shared.Maths;
-
-namespace Robust.Client.Map;
-
-/// <summary>
-/// Draws border sprites for tiles that support them.
-/// </summary>
-public sealed class TileEdgeOverlay : GridOverlay
-{
-    private readonly IEntityManager _entManager;
-    private readonly IResourceCache _resource;
-    private readonly ITileDefinitionManager _tileDefManager;
-
-    public TileEdgeOverlay(IEntityManager entManager, IResourceCache resource, ITileDefinitionManager tileDefManager)
-    {
-        _entManager = entManager;
-        _resource = resource;
-        _tileDefManager = tileDefManager;
-        ZIndex = -1;
-    }
-
-    protected internal override void Draw(in OverlayDrawArgs args)
-    {
-        if (args.MapId == MapId.Nullspace)
-            return;
-
-        var mapSystem = _entManager.System<SharedMapSystem>();
-        var xformSystem = _entManager.System<SharedTransformSystem>();
-
-        var tileSize = Grid.Comp.TileSize;
-        var tileDimensions = new Vector2(tileSize, tileSize);
-        var (_, _, worldMatrix, invMatrix) = xformSystem.GetWorldPositionRotationMatrixWithInv(Grid.Owner);
-        args.WorldHandle.SetTransform(worldMatrix);
-        var bounds = args.WorldBounds;
-        bounds = new Box2Rotated(bounds.Box.Enlarged(1), bounds.Rotation, bounds.Origin);
-        var localAABB = invMatrix.TransformBox(bounds);
-
-        var enumerator = mapSystem.GetLocalTilesEnumerator(Grid.Owner, Grid, localAABB, false);
-
-        while (enumerator.MoveNext(out var tileRef))
-        {
-            var tileDef = _tileDefManager[tileRef.Tile.TypeId];
-
-            if (tileDef.EdgeSprites.Count == 0)
-                continue;
-
-            // Get what tiles border us to determine what sprites we need to draw.
-            for (var x = -1; x <= 1; x++)
-            {
-                for (var y = -1; y <= 1; y++)
-                {
-                    if (x == 0 && y == 0)
-                        continue;
-
-                    var neighborIndices = new Vector2i(tileRef.GridIndices.X + x, tileRef.GridIndices.Y + y);
-                    var neighborTile = mapSystem.GetTileRef(Grid.Owner, Grid, neighborIndices);
-                    var neighborDef = _tileDefManager[neighborTile.Tile.TypeId];
-
-                    // If it's the same tile then no edge to be drawn.
-                    if (tileRef.Tile.TypeId == neighborTile.Tile.TypeId)
-                        continue;
-
-                    // Don't draw if the the neighbor tile edges should draw over us (or if we have the same priority)
-                    if (neighborDef.EdgeSprites.Count != 0 && neighborDef.EdgeSpritePriority >= tileDef.EdgeSpritePriority)
-                        continue;
-
-                    var direction = new Vector2i(x, y).AsDirection();
-
-                    // No edge tile
-                    if (!tileDef.EdgeSprites.TryGetValue(direction, out var edgePath))
-                        continue;
-
-                    var texture = _resource.GetResource<TextureResource>(edgePath);
-                    var box = Box2.FromDimensions(neighborIndices, tileDimensions);
-
-                    var angle = Angle.Zero;
-
-                    // If we ever need one for both cardinals and corners then update this.
-                    switch (direction)
-                    {
-                        // Corner sprites
-                        case Direction.SouthEast:
-                            break;
-                        case Direction.NorthEast:
-                            angle = new Angle(MathF.PI / 2f);
-                            break;
-                        case Direction.NorthWest:
-                            angle = new Angle(MathF.PI);
-                            break;
-                        case Direction.SouthWest:
-                            angle = new Angle(MathF.PI * 1.5f);
-                            break;
-                        // Edge sprites
-                        case Direction.South:
-                            break;
-                        case Direction.East:
-                            angle = new Angle(MathF.PI / 2f);
-                            break;
-                        case Direction.North:
-                            angle = new Angle(MathF.PI);
-                            break;
-                        case Direction.West:
-                            angle = new Angle(MathF.PI * 1.5f);
-                            break;
-                    }
-
-                    if (angle == Angle.Zero)
-                        args.WorldHandle.DrawTextureRect(texture.Texture, box);
-                    else
-                        args.WorldHandle.DrawTextureRect(texture.Texture, new Box2Rotated(box, angle, box.Center));
-
-                    RequiresFlush = true;
-                }
-            }
-        }
-
-        args.WorldHandle.SetTransform(Matrix3x2.Identity);
-    }
-}

Robust.Client/UserInterface/Controls/BoxContainer.cs

@@ -71,21 +71,11 @@ namespace Robust.Client.UserInterface.Controls
             }
 
             // First, we measure non-stretching children.
-            var stretching = new List<Control>();
-            float totalStretchRatio = 0;
             foreach (var child in Children)
             {
                 if (!child.Visible)
                     continue;
 
-                var stretch = Vertical ? child.VerticalExpand : child.HorizontalExpand;
-                if (stretch)
-                {
-                    totalStretchRatio += child.SizeFlagsStretchRatio;
-                    stretching.Add(child);
-                    continue;
-                }
-
                 child.Measure(availableSize);
 
                 if (Vertical)
@@ -102,35 +92,6 @@ namespace Robust.Client.UserInterface.Controls
                 }
             }
 
-            if (stretching.Count == 0)
-                return desiredSize;
-
-            // Then we measure stretching children
-            foreach (var child in stretching)
-            {
-                var size = availableSize;
-                if (Vertical)
-                {
-                    size.Y *= child.SizeFlagsStretchRatio / totalStretchRatio;
-                    child.Measure(size);
-                    desiredSize.Y += child.DesiredSize.Y;
-                    desiredSize.X = Math.Max(desiredSize.X, child.DesiredSize.X);
-                }
-                else
-                {
-                    size.X *= child.SizeFlagsStretchRatio / totalStretchRatio;
-                    child.Measure(size);
-                    desiredSize.X += child.DesiredSize.X;
-                    desiredSize.Y = Math.Max(desiredSize.Y, child.DesiredSize.Y);
-                }
-
-                // TODO Maybe make BoxContainer.MeasureOverride more rigorous.
-                // This should check if size < desired size. If it is, treat child as non-stretching (see the code in
-                // ArrangeOverride). This requires remeasuring all stretching controls + the control that just became
-                // non-stretching. But the re-measured controls might then become smaller (e.g. rich text wrapping),
-                // leading to a recursion problem.
-            }
-
             return desiredSize;
         }
 

Robust.Client/UserInterface/Controls/OutputPanel.cs

@@ -4,6 +4,7 @@ using Robust.Client.Graphics;
 using Robust.Client.UserInterface.RichText;
 using Robust.Shared.Collections;
 using Robust.Shared.IoC;
+using Robust.Shared.Localization;
 using Robust.Shared.Maths;
 using Robust.Shared.Utility;
 
@@ -15,10 +16,23 @@ namespace Robust.Client.UserInterface.Controls
     [Virtual]
     public class OutputPanel : Control
     {
+        public const string StyleClassOutputPanelScrollDownButton = "outputPanelScrollDownButton";
+
         [Dependency] private readonly MarkupTagManager _tagManager = default!;
 
         public const string StylePropertyStyleBox = "stylebox";
 
+        public bool ShowScrollDownButton
+        {
+            get => _showScrollDownButton;
+            set
+            {
+                _showScrollDownButton = value;
+                _updateScrollButtonVisibility();
+            }
+        }
+        private bool _showScrollDownButton;
+
         private readonly RingBufferList<RichTextEntry> _entries = new();
         private bool _isAtBottom = true;
 
@@ -26,6 +40,7 @@ namespace Robust.Client.UserInterface.Controls
         private bool _firstLine = true;
         private StyleBox? _styleBoxOverride;
         private VScrollBar _scrollBar;
+        private Button _scrollDownButton;
 
         public bool ScrollFollowing { get; set; } = true;
 
@@ -43,7 +58,25 @@ namespace Robust.Client.UserInterface.Controls
                 HorizontalAlignment = HAlignment.Right
             };
             AddChild(_scrollBar);
-            _scrollBar.OnValueChanged += _ => _isAtBottom = _scrollBar.IsAtEnd;
+
+            AddChild(_scrollDownButton = new Button()
+            {
+                Name = "scrollLiveBtn",
+                StyleClasses = { StyleClassOutputPanelScrollDownButton },
+                VerticalAlignment = VAlignment.Bottom,
+                HorizontalAlignment = HAlignment.Center,
+                Text = String.Format("⬇    {0}    ⬇", Loc.GetString("output-panel-scroll-down-button-text")),
+                MaxWidth = 300,
+                Visible = false,
+            });
+
+            _scrollDownButton.OnPressed += _ => ScrollToBottom();
+
+            _scrollBar.OnValueChanged += _ =>
+            {
+                _isAtBottom = _scrollBar.IsAtEnd;
+                _updateScrollButtonVisibility();
+            };
         }
 
         public int EntryCount => _entries.Count;
@@ -184,6 +217,7 @@ namespace Robust.Client.UserInterface.Controls
             var styleBoxSize = _getStyleBox()?.MinimumSize.Y ?? 0;
 
             _scrollBar.Page = UIScale * (Height - styleBoxSize);
+            _updateScrollButtonVisibility();
             _invalidateEntries();
         }
 
@@ -284,5 +318,10 @@ namespace Robust.Client.UserInterface.Controls
                 _invalidOnVisible = false;
             }
         }
+
+        private void _updateScrollButtonVisibility()
+        {
+            _scrollDownButton.Visible = ShowScrollDownButton && !_isAtBottom;
+        }
     }
 }

Robust.Client/UserInterface/CustomControls/DebugConsole.xaml

@@ -1,7 +1,7 @@
 <Control xmlns="https://spacestation14.io"
          xmlns:gfx="clr-namespace:Robust.Client.Graphics">
     <BoxContainer Orientation="Vertical">
-        <OutputPanel Name="Output" VerticalExpand="True" StyleClasses="monospace">
+        <OutputPanel Name="Output" VerticalExpand="True" StyleClasses="monospace" ShowScrollDownButton="True">
             <OutputPanel.StyleBoxOverride>
                 <gfx:StyleBoxFlat BackgroundColor="#25252add"
                                   ContentMarginLeftOverride="3" ContentMarginRightOverride="3"

Robust.Client/UserInterface/CustomControls/EntitySpawnWindow.xaml.cs

@@ -59,6 +59,7 @@ namespace Robust.Client.UserInterface.CustomControls
             }
 
             button.EntityLabel.Text = entityLabelText;
+            button.ActualButton.ToolTip = prototype.Description;
 
             if (prototype == SelectedPrototype)
             {

Robust.Client/UserInterface/RichText/FontPrototype.cs

@@ -4,7 +4,7 @@ using Robust.Shared.Utility;
 
 namespace Robust.Client.UserInterface.RichText;
 
-[Prototype("font")]
+[Prototype]
 public sealed partial class FontPrototype : IPrototype
 {
     [IdDataField]

Robust.Roslyn.Shared/Diagnostics.cs

@@ -36,6 +36,7 @@ public static class Diagnostics
     public const string IdUseNonGenericVariant = "RA0030";
     public const string IdPreferOtherType = "RA0031";
     public const string IdDuplicateDependency = "RA0032";
+    public const string IdForbidLiteral = "RA0033";
 
     public static SuppressionDescriptor MeansImplicitAssignment =>
         new SuppressionDescriptor("RADC1000", "CS0649", "Marked as implicitly assigned.");

Robust.Roslyn.Shared/Robust.Roslyn.Shared.props

@@ -14,7 +14,7 @@
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <ImplicitUsings>enable</ImplicitUsings>
     <PolySharpIncludeGeneratedTypes>System.Index;System.Diagnostics.CodeAnalysis.NotNullWhenAttribute;System.Runtime.CompilerServices.IsExternalInit;System.Diagnostics.CodeAnalysis.DoesNotReturnAttribute</PolySharpIncludeGeneratedTypes>
-    <NoWarn>RS2008</NoWarn>
+    <NoWarn>RS2008;RS1038</NoWarn>
   </PropertyGroup>
 
   <ItemGroup>

Robust.Serialization.Generator/Generator.cs

@@ -35,13 +35,20 @@ public class Generator : IIncrementalGenerator
             .Where(static type => type != null);
 
         initContext.RegisterSourceOutput(
-            dataDefinitions,
-            static (sourceContext, source) =>
+            dataDefinitions.Collect(),
+            static (sourceContext, sources) =>
             {
-                // TODO: deduplicate based on name?
-                var (name, code) = source!.Value;
+                var done = new HashSet<string>();
 
-                sourceContext.AddSource(name, code);
+                foreach (var source in sources)
+                {
+                    var (name, code) = source!.Value;
+
+                    if (!done.Add(name))
+                        continue;
+
+                    sourceContext.AddSource(name, code);
+                }
             }
         );
     }

Robust.Server/BaseServer.cs

@@ -297,7 +297,7 @@ namespace Robust.Server
                 : null;
 
             // Set up the VFS
-            _resources.Initialize(dataDir);
+            _resources.Initialize(dataDir, hideUserDataDir: false);
 
             var mountOptions = _commandLineArgs != null
                 ? MountOptions.Merge(_commandLineArgs.MountOptions, Options.MountOptions) : Options.MountOptions;

Robust.Server/Console/Commands/MapCommands.cs

@@ -8,6 +8,7 @@ using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
 using Robust.Shared.Localization;
 using Robust.Shared.Map;
+using Robust.Shared.Map.Components;
 using Robust.Shared.Maths;
 using Robust.Shared.Utility;
 
@@ -46,11 +47,11 @@ namespace Robust.Server.Console.Commands
             bool saveSuccess = _ent.System<MapLoaderSystem>().TrySaveGrid(uid, new ResPath(args[1]));
             if(saveSuccess)
             {
-                    shell.WriteLine("Save successful. Look in the user data directory.");
+                shell.WriteLine("Save successful. Look in the user data directory.");
             }
             else
             {
-                    shell.WriteError("Save unsuccessful!");
+                shell.WriteError("Save unsuccessful!");
             }
         }
 
@@ -59,7 +60,7 @@ namespace Robust.Server.Console.Commands
             switch (args.Length)
             {
                 case 1:
-                    return CompletionResult.FromHint(Loc.GetString("cmd-hint-savebp-id"));
+                    return CompletionResult.FromHintOptions(CompletionHelper.Components<MapGridComponent>(args[0], _ent), Loc.GetString("cmd-hint-savebp-id"));
                 case 2:
                     var opts = CompletionHelper.UserFilePath(args[1], _resource.UserData);
                     return CompletionResult.FromHintOptions(opts, Loc.GetString("cmd-hint-savemap-path"));
@@ -159,6 +160,7 @@ namespace Robust.Server.Console.Commands
 
     public sealed class SaveMap : LocalizedCommands
     {
+        [Dependency] private readonly IEntityManager _entManager = default!;
         [Dependency] private readonly IEntitySystemManager _system = default!;
         [Dependency] private readonly IResourceManager _resource = default!;
 
@@ -169,7 +171,7 @@ namespace Robust.Server.Console.Commands
             switch (args.Length)
             {
                 case 1:
-                    return CompletionResult.FromHint(Loc.GetString("cmd-hint-savemap-id"));
+                    return CompletionResult.FromHintOptions(CompletionHelper.MapIds(_entManager), Loc.GetString("cmd-hint-savemap-id"));
                 case 2:
                     var opts = CompletionHelper.UserFilePath(args[1], _resource.UserData);
                     return CompletionResult.FromHintOptions(opts, Loc.GetString("cmd-hint-savemap-path"));

Robust.Server/GameObjects/ServerEntityManager.cs

@@ -204,6 +204,23 @@ namespace Robust.Server.GameObjects
 
         private void HandleEntityNetworkMessage(MsgEntity message)
         {
+            if (_logLateMsgs)
+            {
+                var msgT = message.SourceTick;
+                var cT = _gameTiming.CurTick;
+
+                if (msgT < cT)
+                {
+                    _netEntSawmill.Warning(
+                        "Got late MsgEntity! Diff: {0}, msgT: {2}, cT: {3}, player: {1}, msg: {4}",
+                        (int) msgT.Value - (int) cT.Value,
+                        message.MsgChannel.UserName,
+                        msgT,
+                        cT,
+                        message.SystemMessage);
+                }
+            }
+
             _queue.Add(message);
         }
 

Robust.Server/ServerStatus/StatusExt.cs

@@ -0,0 +1,15 @@
+namespace Robust.Server.ServerStatus;
+
+/// <summary>
+/// Helper functions for working with <see cref="IStatusHandlerContext"/>.
+/// </summary>
+public static class StatusExt
+{
+    /// <summary>
+    /// Add <c>Access-Control-Allow-Origin: *</c> to the response headers for this request.
+    /// </summary>
+    public static void AddAllowOriginAny(this IStatusHandlerContext context)
+    {
+        context.ResponseHeaders.Add("Access-Control-Allow-Origin", "*");
+    }
+}

Robust.Server/ServerStatus/StatusHost.Handlers.cs

@@ -61,6 +61,7 @@ namespace Robust.Server.ServerStatus
 
             OnStatusRequest?.Invoke(jObject);
 
+            context.AddAllowOriginAny();
             await context.RespondJsonAsync(jObject);
 
             return true;
@@ -121,6 +122,7 @@ namespace Robust.Server.ServerStatus
 
             OnInfoRequest?.Invoke(jObject);
 
+            context.AddAllowOriginAny();
             await context.RespondJsonAsync(jObject);
 
             return true;

Robust.Shared.Maths/Angle.cs

@@ -93,6 +93,7 @@ namespace Robust.Shared.Maths
         private const double CardinalSegment = 2 * Math.PI / 4.0; // Cut the circle into 4 pieces
         private const double CardinalOffset = CardinalSegment / 2.0; // offset the pieces by 1/2 their size
 
+        [Pure]
         public readonly Direction GetCardinalDir()
         {
             var ang = Theta % (2 * Math.PI);
@@ -167,6 +168,7 @@ namespace Robust.Shared.Maths
         /// <summary>
         ///     Removes revolutions from a positive or negative angle to make it as small as possible.
         /// </summary>
+        [Pure]
         public readonly Angle Reduced()
         {
             return new(Reduce(Theta));
@@ -213,11 +215,13 @@ namespace Robust.Shared.Maths
             return !(a == b);
         }
 
+        [Pure]
         public readonly Angle Opposite()
         {
             return new Angle(FlipPositive(Theta-Math.PI));
         }
 
+        [Pure]
         public readonly Angle FlipPositive()
         {
             return new(FlipPositive(Theta));

Robust.Shared.Maths/Color.cs

@@ -682,6 +682,7 @@ namespace Robust.Shared.Maths
         ///     (which is copied to the output's Alpha value).
         ///     Each has a range of 0.0 to 1.0.
         /// </param>
+        [Obsolete("The HCY color space is mathematically incorrect and these functions are broken, use something else")]
         public static Color FromHcy(Vector4 hcy)
         {
             var hue = hcy.X * 360.0f;
@@ -750,6 +751,7 @@ namespace Robust.Shared.Maths
         /// </returns>
         /// <param name="rgb">Color value to convert.</param>
         [SuppressMessage("ReSharper", "CompareOfFloatsByEqualityOperator")]
+        [Obsolete("The HCY color space is mathematically incorrect and these functions are broken, use something else")]
         public static Vector4 ToHcy(Color rgb)
         {
             var max = MathF.Max(rgb.R, MathF.Max(rgb.G, rgb.B));

Robust.Shared.Maths/Direction.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Collections.Immutable;
+using System.Diagnostics.Contracts;
 using System.Numerics;
 
 namespace Robust.Shared.Maths
@@ -36,6 +38,21 @@ namespace Robust.Shared.Maths
     /// </summary>
     public static class DirectionExtensions
     {
+        /// <summary>
+        /// A list of all cardinal and diagonal <see cref="Direction"/>s.
+        /// </summary>
+        public static readonly ImmutableArray<Direction> AllDirections =
+        [
+            Direction.South,
+            Direction.SouthEast,
+            Direction.East,
+            Direction.NorthEast,
+            Direction.North,
+            Direction.NorthWest,
+            Direction.West,
+            Direction.SouthWest
+        ];
+
         private const double Segment = 2 * Math.PI / 8.0; // Cut the circle into 8 pieces
 
         public static Direction AsDir(this DirectionFlag directionFlag)
@@ -238,6 +255,7 @@ namespace Robust.Shared.Maths
         /// </summary>
         /// <param name="dir"></param>
         /// <returns></returns>
+        [Pure]
         public static Angle ToAngle(this Direction dir)
         {
             var ang = Segment * (int) dir;

Robust.Shared/Analyzers/ForbidLiteralAttribute.cs

@@ -0,0 +1,11 @@
+using System;
+
+namespace Robust.Shared.Analyzers;
+
+/// <summary>
+/// Marks that values used for this parameter should not be literal values.
+/// This helps prevent magic numbers/strings/etc, by indicating that values
+/// should either be wrapped (for validation) or defined as constants or readonly statics.
+/// </summary>
+[AttributeUsage(AttributeTargets.Parameter)]
+public sealed class ForbidLiteralAttribute : Attribute;

Robust.Shared/Audio/AudioPresetPrototype.cs

@@ -8,7 +8,7 @@ namespace Robust.Shared.Audio;
 /// Contains audio defaults to set for sounds.
 /// This can be used by <see cref="Content.Shared.Audio.SharedContentAudioSystem"/> to apply an audio preset.
 /// </summary>
-[Prototype("audioPreset")]
+[Prototype]
 public sealed partial class AudioPresetPrototype : IPrototype
 {
     [IdDataField]

Robust.Shared/Audio/SoundCollectionPrototype.cs

@@ -6,7 +6,7 @@ using Robust.Shared.ViewVariables;
 
 namespace Robust.Shared.Audio;
 
-[Prototype("soundCollection")]
+[Prototype]
 public sealed partial class SoundCollectionPrototype : IPrototype
 {
     [ViewVariables]

Robust.Shared/CVars.cs

@@ -1874,5 +1874,12 @@ namespace Robust.Shared
         /// </summary>
         public static readonly CVarDef<int> ToolshedNearbyEntitiesLimit =
             CVarDef.Create("toolshed.nearby_entities_limit", 5, CVar.SERVER | CVar.REPLICATED);
+
+        /*
+         * Localization
+         */
+
+        public static readonly CVarDef<string> LocCultureName =
+            CVarDef.Create("loc.culture_name", "en-US", CVar.ARCHIVE);
     }
 }

Robust.Shared/Console/Commands/TeleportCommands.cs

@@ -67,6 +67,17 @@ internal sealed class TeleportCommand : LocalizedEntityCommands
 
         shell.WriteLine($"Teleported {shell.Player} to {mapId}:{posX},{posY}.");
     }
+
+    public override CompletionResult GetCompletion(IConsoleShell shell, string[] args)
+    {
+        return args.Length switch
+        {
+            1 => CompletionResult.FromHint("<x>"),
+            2 => CompletionResult.FromHint("<y>"),
+            3 => CompletionResult.FromHintOptions(CompletionHelper.MapIds(_entityManager), "[MapId]"),
+            _ => CompletionResult.Empty
+        };
+    }
 }
 
 public sealed class TeleportToCommand : LocalizedEntityCommands

Robust.Shared/ContentPack/DirLoader.cs

@@ -60,9 +60,7 @@ namespace Robust.Shared.ContentPack
 
             internal string GetPath(ResPath relPath)
             {
-                return Path.GetFullPath(Path.Combine(_directory.FullName, relPath.ToRelativeSystemPath()))
-                    // Sanitise platform-specific path and standardize it for engine use.
-                    .Replace(Path.DirectorySeparatorChar, '/');
+                return PathHelpers.SafeGetResourcePath(_directory.FullName, relPath);
             }
 
             /// <inheritdoc />

Robust.Shared/ContentPack/IResourceManagerInternal.cs

@@ -14,7 +14,11 @@ namespace Robust.Shared.ContentPack
         /// The directory to use for user data.
         /// If null, a virtual temporary file system is used instead.
         /// </param>
-        void Initialize(string? userData);
+        /// <param name="hideUserDataDir">
+        /// If true, <see cref="IWritableDirProvider.RootDir"/> will be hidden on
+        /// <see cref="IResourceManager.UserData"/>.
+        /// </param>
+        void Initialize(string? userData, bool hideUserDataDir);
 
         /// <summary>
         ///     Mounts a single stream as a content file. Useful for unit testing.

Robust.Shared/ContentPack/IWritableDirProvider.cs

@@ -13,7 +13,7 @@ namespace Robust.Shared.ContentPack
     {
         /// <summary>
         /// The root path of this provider.
-        /// Can be null if it's a virtual provider.
+        /// Can be null if it's a virtual provider or the path is protected (e.g. on the client).
         /// </summary>
         string? RootDir { get; }
 

Robust.Shared/ContentPack/PathHelpers.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Runtime.InteropServices;
+using Robust.Shared.Utility;
 
 namespace Robust.Shared.ContentPack
 {
@@ -63,5 +64,27 @@ namespace Robust.Shared.ContentPack
             !OperatingSystem.IsWindows()
             && !OperatingSystem.IsMacOS();
 
+
+        internal static string SafeGetResourcePath(string baseDir, ResPath path)
+        {
+            var relSysPath = path.ToRelativeSystemPath();
+            if (relSysPath.Contains("\\..") || relSysPath.Contains("/.."))
+            {
+                // Hard cap on any exploit smuggling a .. in there.
+                // Since that could allow leaving sandbox.
+                throw new InvalidOperationException($"This branch should never be reached. Path: {path}");
+            }
+
+            var retPath = Path.GetFullPath(Path.Join(baseDir, relSysPath));
+            // better safe than sorry check
+            if (!retPath.StartsWith(baseDir))
+            {
+                // Allow path to match if it's just missing the directory separator at the end.
+                if (retPath != baseDir.TrimEnd('\\'))
+                    throw new InvalidOperationException($"This branch should never be reached. Path: {path}");
+            }
+
+            return retPath;
+        }
     }
 }

Robust.Shared/ContentPack/ResourceManager.cs

@@ -41,13 +41,13 @@ namespace Robust.Shared.ContentPack
         public IWritableDirProvider UserData { get; private set; } = default!;
 
         /// <inheritdoc />
-        public virtual void Initialize(string? userData)
+        public virtual void Initialize(string? userData, bool hideRootDir)
         {
             Sawmill = _logManager.GetSawmill("res");
 
             if (userData != null)
             {
-                UserData = new WritableDirProvider(Directory.CreateDirectory(userData));
+                UserData = new WritableDirProvider(Directory.CreateDirectory(userData), hideRootDir);
             }
             else
             {
@@ -381,6 +381,10 @@ namespace Robust.Shared.ContentPack
                 {
                     var rootDir = loader.GetPath(new ResPath(@"/"));
 
+                    // TODO: GET RID OF THIS.
+                    // This code shouldn't be passing OS disk paths through ResPath.
+                    rootDir = rootDir.Replace(Path.DirectorySeparatorChar, '/');
+
                     yield return new ResPath(rootDir);
                 }
             }

Robust.Shared/ContentPack/WritableDirProvider.cs

@@ -10,17 +10,22 @@ namespace Robust.Shared.ContentPack
     /// <inheritdoc />
     internal sealed class WritableDirProvider : IWritableDirProvider
     {
-        /// <inheritdoc />
+        private readonly bool _hideRootDir;
+
         public string RootDir { get; }
 
+        string? IWritableDirProvider.RootDir => _hideRootDir ? null : RootDir;
+
         /// <summary>
         /// Constructs an instance of <see cref="WritableDirProvider"/>.
         /// </summary>
         /// <param name="rootDir">Root file system directory to allow writing.</param>
-        public WritableDirProvider(DirectoryInfo rootDir)
+        /// <param name="hideRootDir">If true, <see cref="IWritableDirProvider.RootDir"/> is reported as null.</param>
+        public WritableDirProvider(DirectoryInfo rootDir, bool hideRootDir)
         {
             // FullName does not have a trailing separator, and we MUST have a separator.
             RootDir = rootDir.FullName + Path.DirectorySeparatorChar.ToString();
+            _hideRootDir = hideRootDir;
         }
 
         #region File Access
@@ -119,7 +124,7 @@ namespace Robust.Shared.ContentPack
                 throw new FileNotFoundException();
 
             var dirInfo = new DirectoryInfo(GetFullPath(path));
-            return new WritableDirProvider(dirInfo);
+            return new WritableDirProvider(dirInfo, _hideRootDir);
         }
 
         /// <inheritdoc />
@@ -180,20 +185,7 @@ namespace Robust.Shared.ContentPack
 
             path = path.Clean();
 
-            return GetFullPath(RootDir, path);
-        }
-
-        private static string GetFullPath(string root, ResPath path)
-        {
-            var relPath = path.ToRelativeSystemPath();
-            if (relPath.Contains("\\..") || relPath.Contains("/.."))
-            {
-                // Hard cap on any exploit smuggling a .. in there.
-                // Since that could allow leaving sandbox.
-                throw new InvalidOperationException($"This branch should never be reached. Path: {path}");
-            }
-
-            return Path.GetFullPath(Path.Combine(root, relPath));
+            return PathHelpers.SafeGetResourcePath(RootDir, path);
         }
     }
 }

Robust.Shared/EntitySerialization/Systems/MapLoaderSystem.cs

@@ -47,6 +47,7 @@ public sealed partial class MapLoaderSystem : EntitySystem
         Log.Info($"Saving serialized results to {path}");
         path = path.ToRootedPath();
         var document = new YamlDocument(data.ToYaml());
+        _resourceManager.UserData.CreateDir(path.Directory);
         using var writer = _resourceManager.UserData.OpenWriteText(path);
         {
             var stream = new YamlStream {document};

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

@@ -1,20 +1,22 @@
 using Robust.Shared.Serialization.Manager.Attributes;
 
-namespace Robust.Shared.GameObjects
+namespace Robust.Shared.GameObjects;
+
+/// <summary>
+/// Controls PVS visibility of entities. THIS COMPONENT CONTROLS WHETHER ENTITIES ARE NETWORKED TO PLAYERS
+/// AND SHOULD NOT BE USED AS THE SOLE WAY TO HIDE AN ENTITY FROM A PLAYER.
+/// </summary>
+[RegisterComponent]
+[Access(typeof(SharedVisibilitySystem))]
+public sealed partial class VisibilityComponent : Component
 {
     /// <summary>
-    /// Controls PVS visibility of entities. THIS COMPONENT CONTROLS WHETHER ENTITIES ARE NETWORKED TO PLAYERS
-    /// AND SHOULD NOT BE USED AS THE SOLE WAY TO HIDE AN ENTITY FROM A PLAYER.
+    ///     The visibility layer for the entity.
+    ///     Players whose visibility masks don't match this won't get state updates for it.
     /// </summary>
-    [RegisterComponent]
-    [Access(typeof(SharedVisibilitySystem))]
-    public sealed partial class VisibilityComponent : Component
-    {
-        /// <summary>
-        ///     The visibility layer for the entity.
-        ///     Players whose visibility masks don't match this won't get state updates for it.
-        /// </summary>
-        [DataField("layer")]
-        public ushort Layer = 1;
-    }
+    /// <remarks>
+    /// Not serialized as visibility is normally immediate (i.e. prior to MapInit) and content should be handling it as such.
+    /// </remarks>
+    [DataField(readOnly: true)]
+    public ushort Layer = 1;
 }

Robust.Shared/GameObjects/EntityManager.ComponentDeltas.cs

@@ -59,7 +59,7 @@ public abstract partial class EntityManager
         Dirty(uid, comp, metadata);
     }
 
-    public virtual void DirtyFields<T>(EntityUid uid, T comp, MetaDataComponent? meta, params ReadOnlySpan<string> fields)
+    public virtual void DirtyFields<T>(EntityUid uid, T comp, MetaDataComponent? meta, params string[] fields)
         where T : IComponentDelta
     {
         var compReg = ComponentFactory.GetRegistration(CompIdx.Index<T>());

Robust.Shared/GameObjects/EntitySystem.Proxy.cs

@@ -172,12 +172,22 @@ public partial class EntitySystem
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    protected void DirtyFields<T>(EntityUid uid, T comp, MetaDataComponent? meta, params ReadOnlySpan<string> fields)
+    protected void DirtyFields<T>(EntityUid uid, T comp, MetaDataComponent? meta, params string[] fields)
         where T : IComponentDelta
     {
         EntityManager.DirtyFields(uid, comp, meta, fields);
     }
 
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected void DirtyFields<T>(Entity<T?> ent, MetaDataComponent? meta, params string[] fields)
+        where T : IComponentDelta
+    {
+        if (!Resolve(ent, ref ent.Comp))
+            return;
+
+        EntityManager.DirtyFields(ent, ent.Comp, meta, fields);
+    }
+
     /// <summary>
     ///     Marks a component as dirty. This also implicitly dirties the entity this component belongs to.
     /// </summary>

Robust.Shared/GameObjects/EntitySystem.Subscriptions.cs

@@ -193,7 +193,7 @@ namespace Robust.Shared.GameObjects
                 ComponentEventHandler<TComp, TEvent> handler,
                 Type[]? before = null, Type[]? after = null)
                 where TComp : IComponent
-                where TEvent : EntityEventArgs
+                where TEvent : notnull
             {
                 System.SubscribeLocalEvent(handler, before, after);
             }
@@ -206,7 +206,7 @@ namespace Robust.Shared.GameObjects
                 ComponentEventRefHandler<TComp, TEvent> handler,
                 Type[]? before = null, Type[]? after = null)
                 where TComp : IComponent
-                where TEvent : EntityEventArgs
+                where TEvent : notnull
             {
                 System.SubscribeLocalEvent(handler, before, after);
             }
@@ -219,7 +219,7 @@ namespace Robust.Shared.GameObjects
                 EntityEventRefHandler<TComp, TEvent> handler,
                 Type[]? before = null, Type[]? after = null)
                 where TComp : IComponent
-                where TEvent : EntityEventArgs
+                where TEvent : notnull
             {
                 System.SubscribeLocalEvent(handler, before, after);
             }
@@ -229,7 +229,7 @@ namespace Robust.Shared.GameObjects
             /// </summary>
             /// <remarks>
             /// This can be used by extension methods for <see cref="Subscriptions"/>
-            /// to unsubscribe from from external sources such as CVars.
+            /// to unsubscribe from external sources such as CVars.
             /// </remarks>
             /// <param name="action">An action to be ran when the entity system is shut down.</param>
             public void RegisterUnsubscription(Action action)

Robust.Shared/GameObjects/Systems/CollisionWakeSystem.cs

@@ -96,6 +96,7 @@ namespace Robust.Shared.GameObjects
 
             // If we're attached to the map we'll also just never disable collision due to how grid movement works.
             var canCollide = body.Awake ||
+                             body.ContactCount > 0 ||
                               (TryComp(uid, out JointComponent? jointComponent) && jointComponent.JointCount > 0) ||
                               xform.GridUid == null;
 

Robust.Shared/GameObjects/Systems/EntityLookup.Queries.cs

@@ -9,6 +9,7 @@ using Robust.Shared.Physics;
 using Robust.Shared.Physics.Collision;
 using Robust.Shared.Physics.Collision.Shapes;
 using Robust.Shared.Physics.Dynamics;
+using Robust.Shared.Physics.Shapes;
 using Robust.Shared.Physics.Systems;
 using Robust.Shared.Utility;
 
@@ -406,7 +407,7 @@ public sealed partial class EntityLookupSystem
         var broadphaseInv = _transform.GetInvWorldMatrix(lookupUid);
 
         var localBounds = broadphaseInv.TransformBounds(worldBounds);
-        var polygon = _physics.GetPooled(localBounds);
+        var polygon = new SlimPolygon(localBounds);
         var result = AnyEntitiesIntersecting(lookupUid,
             polygon,
             localBounds.CalcBoundingBox(),
@@ -414,7 +415,6 @@ public sealed partial class EntityLookupSystem
             flags,
             ignored);
 
-        _physics.ReturnPooled(polygon);
         return result;
     }
 
@@ -458,9 +458,8 @@ public sealed partial class EntityLookupSystem
     {
         if (mapId == MapId.Nullspace) return false;
 
-        var polygon = _physics.GetPooled(worldAABB);
+        var polygon = new SlimPolygon(worldAABB);
         var result = AnyEntitiesIntersecting(mapId, polygon, Physics.Transform.Empty, flags);
-        _physics.ReturnPooled(polygon);
         return result;
     }
 
@@ -475,9 +474,8 @@ public sealed partial class EntityLookupSystem
     {
         if (mapId == MapId.Nullspace) return;
 
-        var polygon = _physics.GetPooled(worldAABB);
+        var polygon = new SlimPolygon(worldAABB);
         AddEntitiesIntersecting(mapId, intersecting, polygon, Physics.Transform.Empty, flags);
-        _physics.ReturnPooled(polygon);
     }
 
     #endregion
@@ -487,18 +485,16 @@ public sealed partial class EntityLookupSystem
     public bool AnyEntitiesIntersecting(MapId mapId, Box2Rotated worldBounds, LookupFlags flags = DefaultFlags)
     {
         // Don't need to check contained entities as they have the same bounds as the parent.
-        var polygon = _physics.GetPooled(worldBounds);
+        var polygon = new SlimPolygon(worldBounds);
         var result = AnyEntitiesIntersecting(mapId, polygon, Physics.Transform.Empty, flags);
-        _physics.ReturnPooled(polygon);
         return result;
     }
 
     public HashSet<EntityUid> GetEntitiesIntersecting(MapId mapId, Box2Rotated worldBounds, LookupFlags flags = DefaultFlags)
     {
         var intersecting = new HashSet<EntityUid>();
-        var polygon = _physics.GetPooled(worldBounds);
+        var polygon = new SlimPolygon(worldBounds);
         AddEntitiesIntersecting(mapId, intersecting, polygon, Physics.Transform.Empty, flags);
-        _physics.ReturnPooled(polygon);
         return intersecting;
     }
 
@@ -761,11 +757,10 @@ public sealed partial class EntityLookupSystem
             return;
 
         var localAABB = _transform.GetInvWorldMatrix(gridId).TransformBox(worldAABB);
-        var polygon = _physics.GetPooled(localAABB);
+        var polygon = new SlimPolygon(localAABB);
 
         AddEntitiesIntersecting(gridId, intersecting, polygon, localAABB, Physics.Transform.Empty, flags, lookup);
         AddContained(intersecting, flags);
-        _physics.ReturnPooled(polygon);
     }
 
     public void GetEntitiesIntersecting(EntityUid gridId, Box2Rotated worldBounds, HashSet<EntityUid> intersecting, LookupFlags flags = DefaultFlags)
@@ -774,11 +769,10 @@ public sealed partial class EntityLookupSystem
             return;
 
         var localBounds = _transform.GetInvWorldMatrix(gridId).TransformBounds(worldBounds);
-        var polygon = _physics.GetPooled(localBounds);
+        var polygon = new SlimPolygon(localBounds);
 
         AddEntitiesIntersecting(gridId, intersecting, polygon, localBounds.CalcBoundingBox(), Physics.Transform.Empty, flags, lookup);
         AddContained(intersecting, flags);
-        _physics.ReturnPooled(polygon);
     }
 
     #endregion

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

@@ -121,9 +121,8 @@ public sealed partial class EntityLookupSystem
         if (!_broadQuery.Resolve(lookupUid, ref lookup))
             return;
 
-        var polygon = _physics.GetPooled(localAABB);
+        var polygon = new SlimPolygon(localAABB);
         AddEntitiesIntersecting(lookupUid, intersecting, polygon, localAABB, Physics.Transform.Empty, flags, query, lookup);
-        _physics.ReturnPooled(polygon);
     }
 
     private void AddEntitiesIntersecting<T, TShape>(
@@ -252,11 +251,10 @@ public sealed partial class EntityLookupSystem
         if (!_broadQuery.Resolve(lookupUid, ref lookup))
             return false;
 
-        var polygon = _physics.GetPooled(localAABB);
+        var polygon = new SlimPolygon(localAABB);
         var (lookupPos, lookupRot) = _transform.GetWorldPositionRotation(lookupUid);
         var transform = new Transform(lookupPos, lookupRot);
         var result = AnyComponentsIntersecting(lookupUid, polygon, localAABB, transform, flags, query, ignored, lookup);
-        _physics.ReturnPooled(polygon);
 
         return result;
     }
@@ -427,10 +425,9 @@ public sealed partial class EntityLookupSystem
 
     public bool AnyComponentsIntersecting(Type type, MapId mapId, Box2 worldAABB, EntityUid? ignored = null, LookupFlags flags = DefaultFlags)
     {
-        var polygon = _physics.GetPooled(worldAABB);
+        var polygon = new SlimPolygon(worldAABB);
         var transform = Physics.Transform.Empty;
         var result = AnyComponentsIntersecting(type, mapId, polygon, transform, ignored, flags);
-        _physics.ReturnPooled(polygon);
         return result;
     }
 
@@ -496,33 +493,30 @@ public sealed partial class EntityLookupSystem
         if (mapId == MapId.Nullspace)
             return;
 
-        var polygon = _physics.GetPooled(worldAABB);
+        var polygon = new SlimPolygon(worldAABB);
         var transform = Physics.Transform.Empty;
 
         GetEntitiesIntersecting(type, mapId, polygon, transform, intersecting, flags);
-        _physics.ReturnPooled(polygon);
     }
 
     public void GetEntitiesIntersecting<T>(MapId mapId, Box2Rotated worldBounds, HashSet<Entity<T>> entities, LookupFlags flags = DefaultFlags) where T : IComponent
     {
         if (mapId == MapId.Nullspace) return;
 
-        var polygon = _physics.GetPooled(worldBounds);
+        var polygon = new SlimPolygon(worldBounds);
         var shapeTransform = Physics.Transform.Empty;
 
         GetEntitiesIntersecting(mapId, polygon, shapeTransform, entities, flags);
-        _physics.ReturnPooled(polygon);
     }
 
     public void GetEntitiesIntersecting<T>(MapId mapId, Box2 worldAABB, HashSet<Entity<T>> entities, LookupFlags flags = DefaultFlags) where T : IComponent
     {
         if (mapId == MapId.Nullspace) return;
 
-        var polygon = _physics.GetPooled(worldAABB);
+        var polygon = new SlimPolygon(worldAABB);
         var shapeTransform = Physics.Transform.Empty;
 
         GetEntitiesIntersecting(mapId, polygon, shapeTransform, entities, flags);
-        _physics.ReturnPooled(polygon);
     }
 
     #endregion

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

@@ -26,7 +26,7 @@ public sealed partial class EntityLookupSystem
         if (!_broadQuery.Resolve(lookupUid, ref lookup))
             return;
 
-        var lookupPoly = new Polygon(localAABB);
+        var lookupPoly = new SlimPolygon(localAABB);
         AddEntitiesIntersecting(lookupUid, intersecting, lookupPoly, localAABB, Physics.Transform.Empty, flags, lookup);
     }
 
@@ -40,7 +40,7 @@ public sealed partial class EntityLookupSystem
         if (!_broadQuery.Resolve(lookupUid, ref lookup))
             return;
 
-        var shape = new Polygon(localBounds);
+        var shape = new SlimPolygon(localBounds);
         var localAABB = localBounds.CalcBoundingBox();
 
         AddEntitiesIntersecting(lookupUid, intersecting, shape, localAABB, Physics.Transform.Empty, flags);
@@ -55,7 +55,7 @@ public sealed partial class EntityLookupSystem
         if (!_broadQuery.Resolve(lookupUid, ref lookup))
             return false;
 
-        var shape = new Polygon(localAABB);
+        var shape = new SlimPolygon(localAABB);
         return AnyEntitiesIntersecting(lookupUid, shape, localAABB, Physics.Transform.Empty, flags, ignored, lookup);
     }
 

Robust.Shared/GameObjects/Systems/SharedEyeSystem.cs

@@ -159,6 +159,10 @@ public abstract class SharedEyeSystem : EntitySystem
         eye.Comp.PvsScale = Math.Clamp(scale, 0.1f, 100f);
     }
 
+    /// <summary>
+    /// Overwrites visibility mask of an entity's eye.
+    /// If you wish for other systems to potentially change it consider raising <see cref="RefreshVisibilityMask"/>.
+    /// </summary>
     public void SetVisibilityMask(EntityUid uid, int value, EyeComponent? eyeComponent = null)
     {
         if (!Resolve(uid, ref eyeComponent))
@@ -170,4 +174,32 @@ public abstract class SharedEyeSystem : EntitySystem
         eyeComponent.VisibilityMask = value;
         DirtyField(uid, eyeComponent, nameof(EyeComponent.VisibilityMask));
     }
+
+    /// <summary>
+    /// Updates the visibility mask for an entity by raising a <see cref="GetVisMaskEvent"/>
+    /// </summary>
+    public void RefreshVisibilityMask(Entity<EyeComponent?> entity)
+    {
+        if (!Resolve(entity.Owner, ref entity.Comp, false))
+            return;
+
+        var ev = new GetVisMaskEvent()
+        {
+            Entity = entity.Owner,
+        };
+        RaiseLocalEvent(entity.Owner, ref ev, true);
+
+        SetVisibilityMask(entity.Owner, ev.VisibilityMask, entity.Comp);
+    }
+}
+
+/// <summary>
+/// Event raised to update the vismask of an entity's eye.
+/// </summary>
+[ByRefEvent]
+public record struct GetVisMaskEvent()
+{
+    public EntityUid Entity;
+
+    public int VisibilityMask = EyeComponent.DefaultVisibilityMask;
 }

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

@@ -111,7 +111,7 @@ public abstract partial class SharedTransformSystem
 
     public EntityUid? GetGrid(Entity<TransformComponent?> entity)
     {
-        return !Resolve(entity, ref entity.Comp) ? null : entity.Comp.GridUid;
+        return !Resolve(entity, ref entity.Comp, logMissing:false) ? null : entity.Comp.GridUid;
     }
 
     /// <summary>
@@ -124,7 +124,7 @@ public abstract partial class SharedTransformSystem
 
     public MapId GetMapId(Entity<TransformComponent?> entity)
     {
-        return !Resolve(entity, ref entity.Comp) ? MapId.Nullspace : entity.Comp.MapID;
+        return !Resolve(entity, ref entity.Comp, logMissing: false) ? MapId.Nullspace : entity.Comp.MapID;
     }
 
     /// <summary>
@@ -137,7 +137,7 @@ public abstract partial class SharedTransformSystem
 
     public EntityUid? GetMap(Entity<TransformComponent?> entity)
     {
-        return !Resolve(entity, ref entity.Comp) ? null : entity.Comp.MapUid;
+        return !Resolve(entity, ref entity.Comp, logMissing: false) ? null : entity.Comp.MapUid;
     }
 
     /// <summary>
@@ -167,10 +167,10 @@ public abstract partial class SharedTransformSystem
     /// </summary>
     public bool InRange(Entity<TransformComponent?> entA, Entity<TransformComponent?> entB,  float range)
     {
-        if (!Resolve(entA, ref entA.Comp))
+        if (!Resolve(entA, ref entA.Comp, logMissing: false))
             return false;
 
-        if (!Resolve(entB, ref entB.Comp))
+        if (!Resolve(entB, ref entB.Comp, logMissing: false))
             return false;
 
         if (!entA.Comp.ParentUid.IsValid() || !entB.Comp.ParentUid.IsValid())

Robust.Shared/GameObjects/Systems/SharedUserInterfaceSystem.cs

@@ -121,7 +121,7 @@ public abstract class SharedUserInterfaceSystem : EntitySystem
         if (msg.Message is not CloseBoundInterfaceMessage && ui.RequireInputValidation)
         {
             var attempt = new BoundUserInterfaceMessageAttempt(sender, uid, msg.UiKey, msg.Message);
-            RaiseLocalEvent(attempt);
+            RaiseLocalEvent(uid, attempt);
             if (attempt.Cancelled)
                 return;
         }

Robust.Shared/Localization/ILocalizationManager.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using JetBrains.Annotations;
@@ -95,9 +96,15 @@ namespace Robust.Shared.Localization
         CultureInfo? DefaultCulture { get; set; }
 
         /// <summary>
-        ///     Checks if the culture has been loaded.
+        /// Checks if the culture is loaded, if not,
+        /// loads it via <see cref="ILocalizationManager.LoadCulture"/>
+        /// and then set it as <see cref="ILocalizationManager.DefaultCulture"/>.
+        /// </summary>
+        void SetCulture(CultureInfo culture);
+
+        /// <summary>
+        /// Checks to see if the culture has been loaded.
         /// </summary>
-        /// <param name="culture"></param>
         bool HasCulture(CultureInfo culture);
 
         /// <summary>
@@ -106,6 +113,17 @@ namespace Robust.Shared.Localization
         /// <param name="culture"></param>
         void LoadCulture(CultureInfo culture);
 
+        /// <summary>
+        /// Loads <see cref="CultureInfo"/> obtained from <see cref="CVars.LocCultureName"/>,
+        /// they are different for client and server, and also can be saved.
+        /// </summary>
+        CultureInfo SetDefaultCulture();
+
+        /// <summary>
+        /// Returns all locale directories from the game's resources.
+        /// </summary>
+        List<CultureInfo> GetFoundCultures();
+
         /// <summary>
         ///     Sets culture to be used in the absence of the main one.
         /// </summary>

Robust.Shared/Localization/LocalizationManager.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.IO;
@@ -12,6 +13,7 @@ using Linguini.Shared.Types.Bundle;
 using Linguini.Syntax.Ast;
 using Linguini.Syntax.Parser;
 using Linguini.Syntax.Parser.Error;
+using Robust.Shared.Configuration;
 using Robust.Shared.ContentPack;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
@@ -24,6 +26,9 @@ namespace Robust.Shared.Localization
 {
     internal sealed partial class LocalizationManager : ILocalizationManagerInternal, IPostInjectInit
     {
+        private static readonly ResPath LocaleDirPath = new("/Locale");
+
+        [Dependency] private readonly IConfigurationManager _configuration = default!;
         [Dependency] private readonly IResourceManager _res = default!;
         [Dependency] private readonly ILogManager _log = default!;
         [Dependency] private readonly IPrototypeManager _prototype = default!;
@@ -41,6 +46,18 @@ namespace Robust.Shared.Localization
             _prototype.PrototypesReloaded += OnPrototypesReloaded;
         }
 
+        public CultureInfo SetDefaultCulture()
+        {
+            var code = _configuration.GetCVar(CVars.LocCultureName);
+
+            var culture = CultureInfo.GetCultureInfo(code, predefinedOnly: false);
+            SetCulture(culture);
+
+            // Return the culture for further work with it,
+            // like of adding functions
+            return culture;
+        }
+
         public string GetString(string messageId)
         {
             if (_defaultCulture == null)
@@ -337,6 +354,17 @@ namespace Robust.Shared.Localization
             }
         }
 
+        public void SetCulture(CultureInfo culture)
+        {
+            if (!HasCulture(culture))
+                LoadCulture(culture);
+
+            if (DefaultCulture?.NameEquals(culture) ?? false)
+                return;
+
+            DefaultCulture = culture;
+        }
+
         public bool HasCulture(CultureInfo culture)
         {
             return _contexts.ContainsKey(culture);
@@ -344,6 +372,10 @@ namespace Robust.Shared.Localization
 
         public void LoadCulture(CultureInfo culture)
         {
+            // Attempting to load an already loaded culture
+            if (HasCulture(culture))
+                throw new InvalidOperationException("Culture is already loaded");
+
             var bundle = LinguiniBuilder.Builder()
                 .CultureInfo(culture)
                 .SkipResources()
@@ -358,6 +390,20 @@ namespace Robust.Shared.Localization
             DefaultCulture ??= culture;
         }
 
+        public List<CultureInfo> GetFoundCultures()
+        {
+            var result = new List<CultureInfo>();
+            foreach (var name in _res.ContentGetDirectoryEntries(LocaleDirPath))
+            {
+                // Remove last "/" symbol
+                // Example "en-US/" -> "en-US"
+                var cultureName = name.TrimEnd('/');
+                result.Add(CultureInfo.GetCultureInfo(cultureName, predefinedOnly: false));
+            }
+
+            return result;
+        }
+
         public void SetFallbackCluture(params CultureInfo[] cultures)
         {
             _fallbackCultures = Array.Empty<(CultureInfo, FluentBundle)>();
@@ -438,7 +484,7 @@ namespace Robust.Shared.Localization
             // Load data from .ftl files.
             // Data is loaded from /Locale/<language-code>/*
 
-            var root = new ResPath($"/Locale/{culture.Name}/");
+            var root = LocaleDirPath / culture.Name;
 
             var files = resourceManager.ContentFindFiles(root)
                 .Where(c => c.Filename.EndsWith(".ftl", StringComparison.InvariantCultureIgnoreCase))

Robust.Shared/Map/MapManager.Queries.cs

@@ -8,6 +8,7 @@ using Robust.Shared.Map.Enumerators;
 using Robust.Shared.Maths;
 using Robust.Shared.Physics;
 using Robust.Shared.Physics.Collision.Shapes;
+using Robust.Shared.Physics.Shapes;
 
 namespace Robust.Shared.Map;
 
@@ -224,48 +225,42 @@ internal partial class MapManager
 
     public void FindGridsIntersecting(EntityUid mapEnt, Box2 worldAABB, GridCallback callback, bool approx = IMapManager.Approximate, bool includeMap = IMapManager.IncludeMap)
     {
-        var polygon = _physics.GetPooled(worldAABB);
+        var polygon = new SlimPolygon(worldAABB);
         FindGridsIntersecting(mapEnt, polygon, worldAABB, Transform.Empty, callback, approx, includeMap);
-        _physics.ReturnPooled(polygon);
     }
 
     public void FindGridsIntersecting<TState>(EntityUid mapEnt, Box2 worldAABB, ref TState state, GridCallback<TState> callback, bool approx = IMapManager.Approximate, bool includeMap = IMapManager.IncludeMap)
     {
-        var polygon = _physics.GetPooled(worldAABB);
+        var polygon = new SlimPolygon(worldAABB);
         FindGridsIntersecting(mapEnt, polygon, worldAABB, Transform.Empty, ref state, callback, approx, includeMap);
-        _physics.ReturnPooled(polygon);
     }
 
     public void FindGridsIntersecting(EntityUid mapEnt, Box2 worldAABB, ref List<Entity<MapGridComponent>> grids,
         bool approx = IMapManager.Approximate, bool includeMap = IMapManager.IncludeMap)
     {
-        var polygon = _physics.GetPooled(worldAABB);
+        var polygon = new SlimPolygon(worldAABB);
         FindGridsIntersecting(mapEnt, polygon, worldAABB, Transform.Empty, ref grids, approx, includeMap);
-        _physics.ReturnPooled(polygon);
     }
 
     public void FindGridsIntersecting(EntityUid mapEnt, Box2Rotated worldBounds, GridCallback callback, bool approx = IMapManager.Approximate,
         bool includeMap = IMapManager.IncludeMap)
     {
-        var polygon = _physics.GetPooled(worldBounds);
+        var polygon = new SlimPolygon(worldBounds);
         FindGridsIntersecting(mapEnt, polygon, worldBounds.CalcBoundingBox(), Transform.Empty, callback, approx, includeMap);
-        _physics.ReturnPooled(polygon);
     }
 
     public void FindGridsIntersecting<TState>(EntityUid mapEnt, Box2Rotated worldBounds, ref TState state, GridCallback<TState> callback,
         bool approx = IMapManager.Approximate, bool includeMap = IMapManager.IncludeMap)
     {
-        var polygon = _physics.GetPooled(worldBounds);
+        var polygon = new SlimPolygon(worldBounds);
         FindGridsIntersecting(mapEnt, polygon, worldBounds.CalcBoundingBox(), Transform.Empty, ref state, callback, approx, includeMap);
-        _physics.ReturnPooled(polygon);
     }
 
     public void FindGridsIntersecting(EntityUid mapEnt, Box2Rotated worldBounds, ref List<Entity<MapGridComponent>> grids,
         bool approx = IMapManager.Approximate, bool includeMap = IMapManager.IncludeMap)
     {
-        var polygon = _physics.GetPooled(worldBounds);
+        var polygon = new SlimPolygon(worldBounds);
         FindGridsIntersecting(mapEnt, polygon, worldBounds.CalcBoundingBox(), Transform.Empty, ref grids, approx, includeMap);
-        _physics.ReturnPooled(polygon);
     }
 
     #endregion

Robust.Shared/Map/TileDefinitionManager.cs

@@ -1,8 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using Robust.Shared.IoC;
-using Robust.Shared.Prototypes;
 using Robust.Shared.Random;
 
 namespace Robust.Shared.Map

Robust.Shared/Physics/Collision/CollisionManager.Circles.cs

@@ -27,7 +27,7 @@ internal sealed partial class CollisionManager
         manifold.LocalNormal = Vector2.Zero;
         manifold.PointCount = 1;
 
-        ref var p0 = ref manifold.Points[0];
+        ref var p0 = ref manifold.Points._00;
 
         p0.LocalPoint = Vector2.Zero; // Also here
         p0.Id.Key = 0;

Robust.Shared/Physics/Collision/CollisionManager.EdgeCircle.cs

@@ -79,9 +79,9 @@ internal sealed partial class CollisionManager
 		        manifold.Type = ManifoldType.Circles;
 		        manifold.LocalNormal = Vector2.Zero;
 		        manifold.LocalPoint = P;
-		        manifold.Points[0].Id.Key = 0;
-		        manifold.Points[0].Id.Features = cf;
-		        manifold.Points[0].LocalPoint = circleB.Position;
+		        manifold.Points._00.Id.Key = 0;
+		        manifold.Points._00.Id.Features = cf;
+		        manifold.Points._00.LocalPoint = circleB.Position;
 		        return;
 	        }
 
@@ -114,9 +114,9 @@ internal sealed partial class CollisionManager
 		        manifold.Type = ManifoldType.Circles;
 		        manifold.LocalNormal = Vector2.Zero;
 		        manifold.LocalPoint = P;
-		        manifold.Points[0].Id.Key = 0;
-		        manifold.Points[0].Id.Features = cf;
-		        manifold.Points[0].LocalPoint = circleB.Position;
+		        manifold.Points._00.Id.Key = 0;
+		        manifold.Points._00.Id.Features = cf;
+		        manifold.Points._00.LocalPoint = circleB.Position;
 		        return;
 	        }
 
@@ -142,8 +142,8 @@ internal sealed partial class CollisionManager
 	        manifold.Type = ManifoldType.FaceA;
 	        manifold.LocalNormal = n;
 	        manifold.LocalPoint = A;
-	        manifold.Points[0].Id.Key = 0;
-	        manifold.Points[0].Id.Features = cf;
-	        manifold.Points[0].LocalPoint = circleB.Position;
+	        manifold.Points._00.Id.Key = 0;
+	        manifold.Points._00.Id.Features = cf;
+	        manifold.Points._00.LocalPoint = circleB.Position;
         }
 }

Robust.Shared/Physics/Collision/CollisionManager.EdgePolygon.cs

@@ -238,15 +238,15 @@ internal sealed partial class CollisionManager
 	    }
 
 	    var pointCount = 0;
+        var points = manifold.Points.AsSpan;
+
 	    for (var i = 0; i < 2; ++i)
 	    {
-		    float separation;
-
-		    separation = Vector2.Dot(refFace.normal, clipPoints2[i].V - refFace.v1);
+            var separation = Vector2.Dot(refFace.normal, clipPoints2[i].V - refFace.v1);
 
 		    if (separation <= radius)
 		    {
-			    ref var cp = ref manifold.Points[pointCount];
+			    ref var cp = ref points[pointCount];
 
 			    if (primaryAxis.Type == EPAxisType.EdgeA)
 			    {

Robust.Shared/Physics/Collision/CollisionManager.Overlap.cs

@@ -12,7 +12,9 @@ internal sealed partial class CollisionManager
     /// <param name="xfA">The transform for the first shape.</param>
     /// <param name="xfB">The transform for the seconds shape.</param>
     /// <returns></returns>
-    public bool TestOverlap<T, U>(T shapeA, int indexA, U shapeB, int indexB, in Transform xfA, in Transform xfB) where T : IPhysShape where U : IPhysShape
+    public bool TestOverlap<T, U>(T shapeA, int indexA, U shapeB, int indexB, in Transform xfA, in Transform xfB)
+        where T : IPhysShape
+        where U : IPhysShape
     {
         var input = new DistanceInput();
 

Robust.Shared/Physics/Collision/CollisionManager.PolygonCircle.cs

@@ -64,7 +64,7 @@ internal sealed partial class CollisionManager
 		    manifold.LocalNormal = normals[normalIndex];
 		    manifold.LocalPoint = (v1 + v2) * 0.5f;
 
-            ref var p0 = ref manifold.Points[0];
+            ref var p0 = ref manifold.Points._00;
 
 		    p0.LocalPoint = circleB.Position;
 		    p0.Id.Key = 0;
@@ -88,7 +88,7 @@ internal sealed partial class CollisionManager
 		    manifold.LocalNormal = (cLocal - v1).Normalized();
             manifold.LocalPoint = v1;
 
-            ref var p0 = ref manifold.Points[0];
+            ref var p0 = ref manifold.Points._00;
 
 		    p0.LocalPoint = circleB.Position;
 		    p0.Id.Key = 0;
@@ -107,7 +107,7 @@ internal sealed partial class CollisionManager
 		    manifold.LocalNormal = (cLocal - v2).Normalized();
             manifold.LocalPoint = v2;
 
-            ref var p0 = ref manifold.Points[0];
+            ref var p0 = ref manifold.Points._00;
 
 		    p0.LocalPoint = circleB.Position;
 		    p0.Id.Key = 0;
@@ -126,7 +126,7 @@ internal sealed partial class CollisionManager
 		    manifold.LocalNormal = normals[vertIndex1];
 		    manifold.LocalPoint = faceCenter;
 
-            ref var p0 = ref manifold.Points[0];
+            ref var p0 = ref manifold.Points._00;
 
 		    p0.LocalPoint = circleB.Position;
             p0.Id.Key = 0;

Robust.Shared/Physics/Collision/CollisionManager.Polygons.cs

@@ -238,6 +238,8 @@ internal sealed partial class CollisionManager
         manifold.LocalPoint = planePoint;
 
         int pointCount = 0;
+        var points = manifold.Points.AsSpan;
+
         for (int i = 0; i < 2; ++i)
         {
             Vector2 value = clipPoints2[i].V;
@@ -245,7 +247,7 @@ internal sealed partial class CollisionManager
 
             if (separation <= totalRadius)
             {
-                ref var cp = ref manifold.Points[pointCount];
+                ref var cp = ref points[pointCount];
                 cp.LocalPoint = Transform.MulT(xf2, clipPoints2[i].V);
                 cp.Id = clipPoints2[i].ID;
 

Robust.Shared/Physics/Collision/CollisionManager.cs

@@ -51,15 +51,18 @@ internal sealed partial class CollisionManager : IManifoldManager
         in Manifold manifold2)
     {
         // Detect persists and removes.
+        var points1 = manifold1.Points.AsSpan;
+        var points2 = manifold2.Points.AsSpan;
+
         for (int i = 0; i < manifold1.PointCount; ++i)
         {
-            ContactID id = manifold1.Points[i].Id;
+            var id = points1[i].Id;
 
             state1[i] = PointState.Remove;
 
             for (int j = 0; j < manifold2.PointCount; ++j)
             {
-                if (manifold2.Points[j].Id.Key == id.Key)
+                if (points2[j].Id.Key == id.Key)
                 {
                     state1[i] = PointState.Persist;
                     break;
@@ -70,13 +73,13 @@ internal sealed partial class CollisionManager : IManifoldManager
         // Detect persists and adds.
         for (int i = 0; i < manifold2.PointCount; ++i)
         {
-            ContactID id = manifold2.Points[i].Id;
+            var id = points2[i].Id;
 
             state2[i] = PointState.Add;
 
-            for (int j = 0; j < manifold1.PointCount; ++j)
+            for (var j = 0; j < manifold1.PointCount; ++j)
             {
-                if (manifold1.Points[j].Id.Key == id.Key)
+                if (points1[j].Id.Key == id.Key)
                 {
                     state2[i] = PointState.Persist;
                     break;

Robust.Shared/Physics/Collision/DistanceProxy.cs

@@ -21,12 +21,9 @@
 */
 
 using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Numerics;
 using System.Runtime.CompilerServices;
-using System.Runtime.InteropServices;
-using Robust.Shared.Map;
 using Robust.Shared.Maths;
 using Robust.Shared.Physics.Collision.Shapes;
 using Robust.Shared.Physics.Shapes;
@@ -46,7 +43,7 @@ internal ref struct DistanceProxy
 
     // GJK using Voronoi regions (Christer Ericson) and Barycentric coordinates.
 
-    internal DistanceProxy(Vector2[] vertices, float radius)
+    internal DistanceProxy(ReadOnlySpan<Vector2> vertices, float radius)
     {
         Vertices = vertices;
         Radius = radius;
@@ -71,9 +68,18 @@ internal ref struct DistanceProxy
             case ShapeType.Polygon:
                 if (shape is Polygon poly)
                 {
-                    Vertices = poly.Vertices.AsSpan()[..poly.VertexCount];
+                    Span<Vector2> verts = new Vector2[poly.VertexCount];
+                    poly._vertices.AsSpan[..poly.VertexCount].CopyTo(verts);
+                    Vertices = verts;
                     Radius = poly.Radius;
                 }
+                else if (shape is SlimPolygon fast)
+                {
+                    Span<Vector2> verts = new Vector2[fast.VertexCount];
+                    fast._vertices.AsSpan[..fast.VertexCount].CopyTo(verts);
+                    Vertices = verts;
+                    Radius = fast.Radius;
+                }
                 else
                 {
                     var polyShape = Unsafe.As<PolygonShape>(shape);
@@ -151,7 +157,7 @@ internal ref struct DistanceProxy
         return Vertices[bestIndex];
     }
 
-    internal static DistanceProxy MakeProxy(Vector2[] vertices, int count, float radius )
+    internal static DistanceProxy MakeProxy(ReadOnlySpan<Vector2> vertices, int count, float radius )
     {
         count = Math.Min(count, PhysicsConstants.MaxPolygonVertices);
         var proxy = new DistanceProxy(vertices[..count], radius);

Robust.Shared/Physics/Collision/Manifold.cs

@@ -25,6 +25,7 @@ using System.Numerics;
 using System.Runtime.InteropServices;
 using Robust.Shared.Localization;
 using Robust.Shared.Maths;
+using Robust.Shared.Utility;
 
 namespace Robust.Shared.Physics.Collision;
 
@@ -146,7 +147,7 @@ public struct Manifold : IEquatable<Manifold>, IApproxEquatable<Manifold>
     /// <summary>
     ///     Points of contact, can only be 0 -> 2.
     /// </summary>
-    internal ManifoldPoint[] Points;
+    internal FixedArray2<ManifoldPoint> Points;
 
     public ManifoldType Type;
 
@@ -157,9 +158,12 @@ public struct Manifold : IEquatable<Manifold>, IApproxEquatable<Manifold>
               LocalNormal.Equals(other.LocalNormal) &&
               LocalPoint.Equals(other.LocalPoint))) return false;
 
+        var points = Points.AsSpan;
+        var otherPoints = other.Points.AsSpan;
+
         for (var i = 0; i < PointCount; i++)
         {
-            if (!Points[i].Equals(other.Points[i])) return false;
+            if (!points[i].Equals(otherPoints[i])) return false;
         }
 
         return true;
@@ -172,9 +176,12 @@ public struct Manifold : IEquatable<Manifold>, IApproxEquatable<Manifold>
               LocalNormal.EqualsApprox(other.LocalNormal) &&
               LocalPoint.EqualsApprox(other.LocalPoint))) return false;
 
+        var points = Points.AsSpan;
+        var otherPoints = other.Points.AsSpan;
+
         for (var i = 0; i < PointCount; i++)
         {
-            if (!Points[i].EqualsApprox(other.Points[i])) return false;
+            if (!points[i].EqualsApprox(otherPoints[i])) return false;
         }
 
         return true;
@@ -187,13 +194,26 @@ public struct Manifold : IEquatable<Manifold>, IApproxEquatable<Manifold>
               LocalNormal.EqualsApprox(other.LocalNormal, tolerance) &&
               LocalPoint.EqualsApprox(other.LocalPoint, tolerance))) return false;
 
+        var points = Points.AsSpan;
+        var otherPoints = other.Points.AsSpan;
+
         for (var i = 0; i < PointCount; i++)
         {
-            if (!Points[i].EqualsApprox(other.Points[i], tolerance)) return false;
+            if (!points[i].EqualsApprox(otherPoints[i], tolerance)) return false;
         }
 
         return true;
     }
+
+    public override bool Equals(object? obj)
+    {
+        return obj is Manifold manifold && Equals(manifold);
+    }
+
+    public override int GetHashCode()
+    {
+        return HashCode.Combine(LocalNormal, LocalPoint, PointCount, Points, (int)Type);
+    }
 }
 
 public struct ManifoldPoint : IEquatable<ManifoldPoint>, IApproxEquatable<ManifoldPoint>

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

@@ -173,10 +173,25 @@ namespace Robust.Shared.Physics.Collision.Shapes
         {
         }
 
+        internal PolygonShape(SlimPolygon poly)
+        {
+            Vertices = new Vector2[poly.VertexCount];
+            Normals = new Vector2[poly.VertexCount];
+
+            poly._vertices.AsSpan[..VertexCount].CopyTo(Vertices);
+            poly._normals.AsSpan[..VertexCount].CopyTo(Normals);
+
+            Centroid = poly.Centroid;
+        }
+
         internal PolygonShape(Polygon poly)
         {
-            Vertices = poly.Vertices;
-            Normals = poly.Normals;
+            Vertices = new Vector2[poly.VertexCount];
+            Normals = new Vector2[poly.VertexCount];
+
+            poly._vertices.AsSpan[..VertexCount].CopyTo(Vertices);
+            poly._normals.AsSpan[..VertexCount].CopyTo(Normals);
+
             Centroid = poly.Centroid;
         }
 

Robust.Shared/Physics/Dynamics/Contacts/Contact.cs

@@ -150,6 +150,15 @@ namespace Robust.Shared.Physics.Dynamics.Contacts
             Friction = MathF.Sqrt((FixtureA?.Friction ?? 0.0f) * (FixtureB?.Friction ?? 0.0f));
         }
 
+        public void GetWorldManifold(Transform transformA, Transform transformB, out Vector2 normal)
+        {
+            var shapeA = FixtureA?.Shape!;
+            var shapeB = FixtureB?.Shape!;
+            Span<Vector2> points = stackalloc Vector2[PhysicsConstants.MaxPolygonVertices];
+
+            SharedPhysicsSystem.InitializeManifold(ref Manifold, transformA, transformB, shapeA.Radius, shapeB.Radius, out normal, points);
+        }
+
         /// <summary>
         /// Gets the world manifold.
         /// </summary>
@@ -197,16 +206,19 @@ namespace Robust.Shared.Physics.Dynamics.Contacts
 
                 // Match old contact ids to new contact ids and copy the
                 // stored impulses to warm start the solver.
+                var points = Manifold.Points.AsSpan;
+                var oldPoints = oldManifold.Points.AsSpan;
+
                 for (var i = 0; i < Manifold.PointCount; ++i)
                 {
-                    var mp2 = Manifold.Points[i];
+                    var mp2 = points[i];
                     mp2.NormalImpulse = 0.0f;
                     mp2.TangentImpulse = 0.0f;
                     var id2 = mp2.Id;
 
                     for (var j = 0; j < oldManifold.PointCount; ++j)
                     {
-                        var mp1 = oldManifold.Points[j];
+                        var mp1 = oldPoints[j];
 
                         if (mp1.Id.Key == id2.Key)
                         {
@@ -216,7 +228,7 @@ namespace Robust.Shared.Physics.Dynamics.Contacts
                         }
                     }
 
-                    Manifold.Points[i] = mp2;
+                    points[i] = mp2;
                 }
 
                 if (touching != wasTouching)
@@ -408,6 +420,28 @@ namespace Robust.Shared.Physics.Dynamics.Contacts
 
             throw new InvalidOperationException();
         }
+
+        [Pure, PublicAPI]
+        public PhysicsComponent OurBody(EntityUid uid)
+        {
+            if (uid == EntityA)
+                return BodyA!;
+            else if (uid == EntityB)
+                return BodyB!;
+
+            throw new InvalidOperationException();
+        }
+
+        [Pure, PublicAPI]
+        public PhysicsComponent OtherBody(EntityUid uid)
+        {
+            if (uid == EntityA)
+                return BodyB!;
+            else if (uid == EntityB)
+                return BodyA!;
+
+            throw new InvalidOperationException();
+        }
     }
 
     [Flags]

Robust.Shared/Physics/Dynamics/Contacts/ContactPositionConstraint.cs

@@ -22,6 +22,7 @@
 
 using System.Numerics;
 using Robust.Shared.Physics.Collision;
+using Robust.Shared.Utility;
 
 namespace Robust.Shared.Physics.Dynamics.Contacts
 {
@@ -37,7 +38,7 @@ namespace Robust.Shared.Physics.Dynamics.Contacts
         /// </summary>
         public int IndexB { get; set; }
 
-        public Vector2[] LocalPoints;
+        internal FixedArray2<Vector2> LocalPoints;
 
         public Vector2 LocalNormal;
 

Robust.Shared/Physics/Dynamics/Contacts/ContactVelocityConstraint.cs

@@ -21,6 +21,7 @@
 */
 
 using System.Numerics;
+using Robust.Shared.Utility;
 
 namespace Robust.Shared.Physics.Dynamics.Contacts
 {
@@ -39,13 +40,13 @@ namespace Robust.Shared.Physics.Dynamics.Contacts
         public int IndexB;
 
         // Use 2 as its the max number of manifold points.
-        public VelocityConstraintPoint[] Points;
+        public FixedArray2<VelocityConstraintPoint> Points;
 
         public Vector2 Normal;
 
-        public System.Numerics.Vector4 NormalMass;
+        public Vector4 NormalMass;
 
-        public System.Numerics.Vector4 K;
+        public Vector4 K;
 
         public float InvMassA;
         public float InvMassB;

Robust.Shared/Physics/Shapes/Polygon.cs

@@ -11,19 +11,28 @@ namespace Robust.Shared.Physics.Shapes;
 // Internal so people don't use it when it will have breaking changes very soon.
 internal record struct Polygon : IPhysShape
 {
-    public static Polygon Empty = new(Box2.Empty);
+    [DataField]
+    public byte VertexCount { get; internal set; }
+
+    /// <summary>
+    /// Vertices associated with this polygon. Will be sliced to <see cref="VertexCount"/>
+    /// </summary>
+    /// <remarks>
+    /// Consider using _vertices if doing engine work.
+    /// </remarks>
+    public Vector2[] Vertices => _vertices.AsSpan[..VertexCount].ToArray();
+
+    public Vector2[] Normals => _normals.AsSpan[..VertexCount].ToArray();
 
     [DataField]
-    public Vector2[] Vertices;
+    internal FixedArray8<Vector2> _vertices;
 
-    public byte VertexCount;
-
-    public Vector2[] Normals;
+    internal FixedArray8<Vector2> _normals;
 
     public Vector2 Centroid;
 
     public int ChildCount => 1;
-    public float Radius { get; set; }
+    public float Radius { get; set; } = PhysicsConstants.PolygonRadius;
     public ShapeType ShapeType => ShapeType.Polygon;
 
     // Hopefully this one is short-lived for a few months
@@ -35,67 +44,60 @@ internal record struct Polygon : IPhysShape
     public Polygon(PolygonShape polyShape)
     {
         Unsafe.SkipInit(out this);
-        Vertices = new Vector2[polyShape.VertexCount];
-        Normals = new Vector2[polyShape.Normals.Length];
         Radius = polyShape.Radius;
         Centroid = polyShape.Centroid;
+        VertexCount = (byte) polyShape.VertexCount;
 
-        Array.Copy(polyShape.Vertices, Vertices, Vertices.Length);
-        Array.Copy(polyShape.Normals, Normals, Vertices.Length);
-        VertexCount = (byte) Vertices.Length;
+        polyShape.Vertices.AsSpan()[..VertexCount].CopyTo(_vertices.AsSpan);
+        polyShape.Normals.AsSpan()[..VertexCount].CopyTo(_normals.AsSpan);
     }
 
-    /// <summary>
-    /// Manually constructed polygon for internal use to take advantage of pooling.
-    /// </summary>
-    internal Polygon(Vector2[] vertices, Vector2[] normals, Vector2 centroid, byte count)
+    public Polygon(Box2 box)
     {
         Unsafe.SkipInit(out this);
-        Vertices = vertices;
-        Normals = normals;
-        Centroid = centroid;
-        VertexCount = count;
-    }
-
-    public Polygon(Box2 aabb)
-    {
-        Unsafe.SkipInit(out this);
-        Vertices = new Vector2[4];
-        Normals = new Vector2[4];
         Radius = 0f;
-
-        Vertices[0] = aabb.BottomLeft;
-        Vertices[1] = aabb.BottomRight;
-        Vertices[2] = aabb.TopRight;
-        Vertices[3] = aabb.TopLeft;
-
-        Normals[0] = new Vector2(0.0f, -1.0f);
-        Normals[1] = new Vector2(1.0f, 0.0f);
-        Normals[2] = new Vector2(0.0f, 1.0f);
-        Normals[3] = new Vector2(-1.0f, 0.0f);
-
         VertexCount = 4;
-        Centroid = aabb.Center;
+
+        _vertices._00 = box.BottomLeft;
+        _vertices._01 = box.BottomRight;
+        _vertices._02 = box.TopRight;
+        _vertices._03 = box.TopLeft;
+
+        _normals._00 = new Vector2(0.0f, -1.0f);
+        _normals._01 = new Vector2(1.0f, 0.0f);
+        _normals._02 = new Vector2(0.0f, 1.0f);
+        _normals._03 = new Vector2(-1.0f, 0.0f);
     }
 
     public Polygon(Box2Rotated bounds)
     {
         Unsafe.SkipInit(out this);
-        Vertices = new Vector2[4];
-        Normals = new Vector2[4];
         Radius = 0f;
-
-        Vertices[0] = bounds.BottomLeft;
-        Vertices[1] = bounds.BottomRight;
-        Vertices[2] = bounds.TopRight;
-        Vertices[3] = bounds.TopLeft;
-
-        CalculateNormals(Normals, 4);
-
         VertexCount = 4;
+
+        _vertices._00 = bounds.BottomLeft;
+        _vertices._01 = bounds.BottomRight;
+        _vertices._02 = bounds.TopRight;
+        _vertices._03 = bounds.TopLeft;
+
+        CalculateNormals(_vertices.AsSpan, _normals.AsSpan, 4);
+
         Centroid = bounds.Center;
     }
 
+    /// <summary>
+    /// Manually constructed polygon for internal use to take advantage of pooling.
+    /// </summary>
+    internal Polygon(ReadOnlySpan<Vector2> vertices, ReadOnlySpan<Vector2> normals, Vector2 centroid, byte count)
+    {
+        Unsafe.SkipInit(out this);
+        vertices[..VertexCount].CopyTo(_vertices.AsSpan);
+        normals[..VertexCount].CopyTo(_normals.AsSpan);
+        Centroid = centroid;
+        VertexCount = count;
+        Radius = 0f;
+    }
+
     public Polygon(Vector2[] vertices)
     {
         Unsafe.SkipInit(out this);
@@ -104,16 +106,15 @@ internal record struct Polygon : IPhysShape
         if (hull.Count < 3)
         {
             VertexCount = 0;
-            Vertices = [];
-            Normals = [];
             return;
         }
 
         VertexCount = (byte) vertices.Length;
-        Vertices = vertices;
-        Normals = new Vector2[vertices.Length];
+        var vertSpan = _vertices.AsSpan;
+
+        vertices.AsSpan().CopyTo(vertSpan);
         Set(hull);
-        Centroid = ComputeCentroid(Vertices);
+        Centroid = ComputeCentroid(vertSpan);
     }
 
     public static explicit operator Polygon(PolygonShape polyShape)
@@ -125,32 +126,32 @@ internal record struct Polygon : IPhysShape
     {
         DebugTools.Assert(hull.Count >= 3);
         var vertexCount = hull.Count;
-        Array.Resize(ref Vertices, vertexCount);
-        Array.Resize(ref Normals, vertexCount);
+        var verts = _vertices.AsSpan;
+        var norms = _normals.AsSpan;
 
         for (var i = 0; i < vertexCount; i++)
         {
-            Vertices[i] = hull.Points[i];
+            verts[i] = hull.Points[i];
         }
 
         // Compute normals. Ensure the edges have non-zero length.
-        CalculateNormals(Normals, vertexCount);
+        CalculateNormals(verts, norms, vertexCount);
     }
 
-    internal void CalculateNormals(Span<Vector2> normals, int count)
+    public static void CalculateNormals(ReadOnlySpan<Vector2> vertices, Span<Vector2> normals, int count)
     {
         for (var i = 0; i < count; i++)
         {
             var next = i + 1 < count ? i + 1 : 0;
-            var edge = Vertices[next] - Vertices[i];
+            var edge = vertices[next] - vertices[i];
             DebugTools.Assert(edge.LengthSquared() > float.Epsilon * float.Epsilon);
 
             var temp = Vector2Helpers.Cross(edge, 1f);
-            Normals[i] = temp.Normalized();
+            normals[i] = temp.Normalized();
         }
     }
 
-    private static Vector2 ComputeCentroid(Vector2[] vs)
+    public static Vector2 ComputeCentroid(ReadOnlySpan<Vector2> vs)
     {
         var count = vs.Length;
         DebugTools.Assert(count >= 3);
@@ -191,13 +192,15 @@ internal record struct Polygon : IPhysShape
 
     public Box2 ComputeAABB(Transform transform, int childIndex)
     {
+        DebugTools.Assert(VertexCount > 0);
         DebugTools.Assert(childIndex == 0);
-        var lower = Transform.Mul(transform, Vertices[0]);
+        var verts = _vertices.AsSpan;
+        var lower = Transform.Mul(transform, verts[0]);
         var upper = lower;
 
         for (var i = 1; i < VertexCount; ++i)
         {
-            var v = Transform.Mul(transform, Vertices[i]);
+            var v = Transform.Mul(transform, verts[i]);
             lower = Vector2.Min(lower, v);
             upper = Vector2.Max(upper, v);
         }
@@ -208,12 +211,41 @@ internal record struct Polygon : IPhysShape
 
     public bool Equals(IPhysShape? other)
     {
-        if (other is not PolygonShape poly) return false;
-        if (VertexCount != poly.VertexCount) return false;
+        if (other is SlimPolygon slim)
+        {
+            return Equals(slim);
+        }
+
+        return other is Polygon poly && Equals(poly);
+    }
+
+    public bool Equals(Polygon other)
+    {
+        if (VertexCount != other.VertexCount) return false;
+
+        var ourVerts = _vertices.AsSpan;
+        var otherVerts = other._vertices.AsSpan;
+
         for (var i = 0; i < VertexCount; i++)
         {
-            var vert = Vertices[i];
-            if (!vert.Equals(poly.Vertices[i])) return false;
+            var vert = ourVerts[i];
+            if (!vert.Equals(otherVerts[i])) return false;
+        }
+
+        return true;
+    }
+
+    public bool Equals(SlimPolygon other)
+    {
+        if (VertexCount != other.VertexCount) return false;
+
+        var ourVerts = _vertices.AsSpan;
+        var otherVerts = other._vertices.AsSpan;
+
+        for (var i = 0; i < VertexCount; i++)
+        {
+            var vert = ourVerts[i];
+            if (!vert.Equals(otherVerts[i])) return false;
         }
 
         return true;
@@ -221,6 +253,6 @@ internal record struct Polygon : IPhysShape
 
     public override int GetHashCode()
     {
-        return HashCode.Combine(VertexCount, Vertices.AsSpan(0, VertexCount).ToArray(), Radius);
+        return HashCode.Combine(VertexCount, _vertices.AsSpan.ToArray(), Radius);
     }
 }

Robust.Shared/Physics/Shapes/SlimPolygon.cs

@@ -0,0 +1,103 @@
+using System;
+using System.Numerics;
+using System.Runtime.CompilerServices;
+using Robust.Shared.Maths;
+using Robust.Shared.Physics.Collision.Shapes;
+using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.Utility;
+
+namespace Robust.Shared.Physics.Shapes;
+
+/// <summary>
+/// Polygon backed by FixedArray4 to be smaller.
+/// Useful for internal ops where the inputs are boxes to avoid the additional padding.
+/// </summary>
+internal record struct SlimPolygon : IPhysShape
+{
+    public Vector2[] Vertices => _vertices.AsSpan[..VertexCount].ToArray();
+
+    public Vector2[] Normals => _normals.AsSpan[..VertexCount].ToArray();
+
+    [DataField]
+    public FixedArray4<Vector2> _vertices;
+
+    public FixedArray4<Vector2> _normals;
+
+    public Vector2 Centroid;
+
+    public byte VertexCount => 4;
+
+    public int ChildCount => 1;
+    public float Radius { get; set; } = PhysicsConstants.PolygonRadius;
+    public ShapeType ShapeType => ShapeType.Polygon;
+
+    public SlimPolygon(Box2 box)
+    {
+        Unsafe.SkipInit(out this);
+        Radius = 0f;
+
+        _vertices._00 = box.BottomLeft;
+        _vertices._01 = box.BottomRight;
+        _vertices._02 = box.TopRight;
+        _vertices._03 = box.TopLeft;
+
+        _normals._00 = new Vector2(0.0f, -1.0f);
+        _normals._01 = new Vector2(1.0f, 0.0f);
+        _normals._02 = new Vector2(0.0f, 1.0f);
+        _normals._03 = new Vector2(-1.0f, 0.0f);
+    }
+
+    public SlimPolygon(Box2Rotated bounds)
+    {
+        Unsafe.SkipInit(out this);
+        Radius = 0f;
+
+        _vertices._00 = bounds.BottomLeft;
+        _vertices._01 = bounds.BottomRight;
+        _vertices._02 = bounds.TopRight;
+        _vertices._03 = bounds.TopLeft;
+
+        Polygon.CalculateNormals(_vertices.AsSpan, _normals.AsSpan, 4);
+
+        Centroid = bounds.Center;
+    }
+
+    public Box2 ComputeAABB(Transform transform, int childIndex)
+    {
+        DebugTools.Assert(VertexCount > 0);
+        DebugTools.Assert(childIndex == 0);
+        var verts = _vertices.AsSpan;
+        var lower = Transform.Mul(transform, verts[0]);
+        var upper = lower;
+
+        for (var i = 1; i < VertexCount; ++i)
+        {
+            var v = Transform.Mul(transform, verts[i]);
+            lower = Vector2.Min(lower, v);
+            upper = Vector2.Max(upper, v);
+        }
+
+        var r = new Vector2(Radius, Radius);
+        return new Box2(lower - r, upper + r);
+    }
+
+    public bool Equals(SlimPolygon other)
+    {
+        return Radius.Equals(other.Radius) && _vertices.AsSpan[..VertexCount].SequenceEqual(other._vertices.AsSpan[..VertexCount]);
+    }
+
+    public readonly override int GetHashCode()
+    {
+        return HashCode.Combine(_vertices, _normals, Centroid, Radius);
+    }
+
+    public bool Equals(IPhysShape? other)
+    {
+        if (other is Polygon poly)
+        {
+            return poly.Equals(this);
+        }
+
+        return other is SlimPolygon slim && Equals(slim);
+    }
+}

Robust.Shared/Physics/Systems/FixtureSystem.Shapes.cs

@@ -40,13 +40,29 @@ namespace Robust.Shared.Physics.Systems
 
                     return true;
                 }
+                case SlimPolygon slim:
+                {
+                    var pLocal = Physics.Transform.MulT(xform.Quaternion2D, worldPoint - xform.Position);
+                    var norms = slim._normals.AsSpan;
+                    var verts = slim._vertices.AsSpan;
+
+                    for (var i = 0; i < slim.VertexCount; i++)
+                    {
+                        var dot = Vector2.Dot(norms[i], pLocal - verts[i]);
+                        if (dot > 0f) return false;
+                    }
+
+                    return true;
+                }
                 case Polygon poly:
                 {
                     var pLocal = Physics.Transform.MulT(xform.Quaternion2D, worldPoint - xform.Position);
+                    var norms = poly._normals.AsSpan;
+                    var verts = poly._vertices.AsSpan;
 
                     for (var i = 0; i < poly.VertexCount; i++)
                     {
-                        var dot = Vector2.Dot(poly.Normals[i], pLocal - poly.Vertices[i]);
+                        var dot = Vector2.Dot(norms[i], pLocal - verts[i]);
                         if (dot > 0f) return false;
                     }
 
@@ -61,109 +77,7 @@ namespace Robust.Shared.Physics.Systems
         {
             var data = new MassData();
 
-            // Box2D just calls fixture.GetMassData which just calls the shape method anyway soooo
-            // we can just cut out the middle-man
-            switch (shape)
-            {
-                case ChainShape:
-                    data.Mass = 0f;
-                    data.Center = Vector2.Zero;
-                    data.I = 0f;
-                    break;
-                case EdgeShape edge:
-                    data.Mass = 0.0f;
-                    data.Center = (edge.Vertex1 + edge.Vertex2) * 0.5f;
-                    data.I = 0.0f;
-                    break;
-                case PhysShapeCircle circle:
-                    // massData->mass = density * b2_pi * m_radius * m_radius;
-                    data.Center = circle.Position;
-
-                    // inertia about the local origin
-                    data.I = data.Mass * (0.5f * circle.Radius * circle.Radius + Vector2.Dot(circle.Position, circle.Position));
-                    break;
-                case PhysShapeAabb aabb:
-                    var polygon = (PolygonShape) aabb;
-                    GetMassData(polygon, ref data, density);
-                    break;
-                case PolygonShape poly:
-                    // Polygon mass, centroid, and inertia.
-                    // Let rho be the polygon density in mass per unit area.
-                    // Then:
-                    // mass = rho * int(dA)
-                    // centroid.x = (1/mass) * rho * int(x * dA)
-                    // centroid.y = (1/mass) * rho * int(y * dA)
-                    // I = rho * int((x*x + y*y) * dA)
-                    //
-                    // We can compute these integrals by summing all the integrals
-                    // for each triangle of the polygon. To evaluate the integral
-                    // for a single triangle, we make a change of variables to
-                    // the (u,v) coordinates of the triangle:
-                    // x = x0 + e1x * u + e2x * v
-                    // y = y0 + e1y * u + e2y * v
-                    // where 0 <= u && 0 <= v && u + v <= 1.
-                    //
-                    // We integrate u from [0,1-v] and then v from [0,1].
-                    // We also need to use the Jacobian of the transformation:
-                    // D = cross(e1, e2)
-                    //
-                    // Simplification: triangle centroid = (1/3) * (p1 + p2 + p3)
-                    //
-                    // The rest of the derivation is handled by computer algebra.
-
-                    var count = poly.VertexCount;
-                    DebugTools.Assert(count >= 3);
-
-                    Vector2 center = new(0.0f, 0.0f);
-                    var area = 0.0f;
-                    var I = 0.0f;
-
-                    // Get a reference point for forming triangles.
-                    // Use the first vertex to reduce round-off errors.
-                    var s = poly.Vertices[0];
-
-                    const float k_inv3 = 1.0f / 3.0f;
-
-                    for (var i = 0; i < count; ++i)
-                    {
-	                    // Triangle vertices.
-	                    var e1 = poly.Vertices[i] - s;
-	                    var e2 = i + 1 < count ? poly.Vertices[i+1] - s : poly.Vertices[0] - s;
-
-	                    var D = Vector2Helpers.Cross(e1, e2);
-
-	                    var triangleArea = 0.5f * D;
-	                    area += triangleArea;
-
-	                    // Area weighted centroid
-	                    center += (e1 + e2) * triangleArea * k_inv3;
-
-	                    float ex1 = e1.X, ey1 = e1.Y;
-	                    float ex2 = e2.X, ey2 = e2.Y;
-
-	                    var intx2 = ex1*ex1 + ex2*ex1 + ex2*ex2;
-	                    var inty2 = ey1*ey1 + ey2*ey1 + ey2*ey2;
-
-	                    I += (0.25f * k_inv3 * D) * (intx2 + inty2);
-                    }
-
-                    // Total mass
-                    data.Mass = density * area;
-
-                    // Center of mass
-                    DebugTools.Assert(area > float.Epsilon);
-                    center *= 1.0f / area;
-                    data.Center = center + s;
-
-                    // Inertia tensor relative to the local origin (point s).
-                    data.I = density * I;
-
-                    // Shift to center of mass then to original body origin.
-                    data.I += data.Mass * (Vector2.Dot(data.Center, data.Center) - Vector2.Dot(center, center));
-                    break;
-                default:
-                    throw new NotImplementedException($"Cannot get MassData for {shape} as it's not implemented!");
-            }
+            GetMassData(shape, ref data, density);
 
             return data;
         }
@@ -195,6 +109,12 @@ namespace Robust.Shared.Physics.Systems
                     var polygon = (PolygonShape) aabb;
                     GetMassData(polygon, ref data, density);
                     break;
+                case Polygon fastPoly:
+                    GetMassData(new PolygonShape(fastPoly), ref data, density);
+                    break;
+                case SlimPolygon slim:
+                    GetMassData(new PolygonShape(slim), ref data, density);
+                    break;
                 case PolygonShape poly:
                     // Polygon mass, centroid, and inertia.
                     // Let rho be the polygon density in mass per unit area.

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

@@ -191,6 +191,12 @@ public sealed partial class RayCastSystem
 
     private CastOutput RayCastPolygon(RayCastInput input, Polygon shape)
     {
+        var verts = shape._vertices.AsSpan;
+        var output = new CastOutput()
+        {
+            Fraction = 0f,
+        };
+
 	    if (shape.Radius == 0.0f)
 	    {
 		    // Put the ray into the polygon's frame of reference.
@@ -201,18 +207,15 @@ public sealed partial class RayCastSystem
 
 		    var index = -1;
 
-		    var output = new CastOutput()
-            {
-                Fraction = 0f,
-            };
+            var norms = shape._normals.AsSpan;
 
 		    for ( var i = 0; i < shape.VertexCount; ++i )
 		    {
 			    // p = p1 + a * d
 			    // dot(normal, p - v) = 0
 			    // dot(normal, p1 - v) + a * dot(normal, d) = 0
-			    float numerator = Vector2.Dot(shape.Normals[i], Vector2.Subtract( shape.Vertices[i], p1 ) );
-			    float denominator = Vector2.Dot(shape.Normals[i], d );
+			    float numerator = Vector2.Dot(norms[i], Vector2.Subtract( verts[i], p1 ) );
+			    float denominator = Vector2.Dot(norms[i], d );
 
 			    if ( denominator == 0.0f )
 			    {
@@ -257,7 +260,7 @@ public sealed partial class RayCastSystem
 		    if (index >= 0)
 		    {
 			    output.Fraction = lower;
-			    output.Normal = shape.Normals[index];
+			    output.Normal = norms[index];
 			    output.Point = Vector2.Add(p1, lower * d);
 			    output.Hit = true;
 		    }
@@ -265,17 +268,24 @@ public sealed partial class RayCastSystem
 		    return output;
 	    }
 
-	    // TODO_ERIN this is not working for ray vs box (zero radii)
+        Span<Vector2> proxyBVerts = new Vector2[]
+        {
+            input.Origin,
+        };
+
+        // TODO_ERIN this is not working for ray vs box (zero radii)
 	    var castInput = new ShapeCastPairInput
         {
-            ProxyA = DistanceProxy.MakeProxy(shape.Vertices, shape.VertexCount, shape.Radius),
-            ProxyB = DistanceProxy.MakeProxy([input.Origin], 1, 0.0f),
+            ProxyA = DistanceProxy.MakeProxy(verts, shape.VertexCount, shape.Radius),
+            ProxyB = DistanceProxy.MakeProxy(proxyBVerts, 1, 0.0f),
             TransformA = Physics.Transform.Empty,
             TransformB = Physics.Transform.Empty,
             TranslationB = input.Translation,
             MaxFraction = input.MaxFraction
         };
-        return ShapeCast(castInput);
+
+        ShapeCast(ref output, castInput);
+        return output;
     }
 
     // Ray vs line segment
@@ -436,12 +446,9 @@ public sealed partial class RayCastSystem
     // "Smooth Mesh Contacts with GJK" in Game Physics Pearls. 2010
     // todo this is failing when used to raycast a box
     // todo this converges slowly with a radius
-    private CastOutput ShapeCast(ShapeCastPairInput input)
+    private void ShapeCast(ref CastOutput output, in ShapeCastPairInput input)
     {
-	    var output = new CastOutput()
-        {
-            Fraction = input.MaxFraction,
-	    };
+        output.Fraction = input.MaxFraction;
 
 	    var proxyA = input.ProxyA;
         var count = input.ProxyB.Vertices.Length;
@@ -513,15 +520,15 @@ public sealed partial class RayCastSystem
 			    if ( vr <= 0.0f )
 			    {
 				    // miss
-				    return output;
-			    }
+                    return;
+                }
 
 			    lambda = ( vp - sigma ) / vr;
 			    if ( lambda > maxFraction )
 			    {
 				    // too far
-				    return output;
-			    }
+                    return;
+                }
 
 			    // reset the simplex
 			    simplex.Count = 0;
@@ -562,7 +569,7 @@ public sealed partial class RayCastSystem
 		    {
 			    // Overlap
                 // Yes this means you need to manually query for overlaps.
-			    return output;
+			    return;
 		    }
 
 		    // Get search direction.
@@ -576,7 +583,7 @@ public sealed partial class RayCastSystem
 	    if ( iter == 0 || lambda == 0.0f )
 	    {
 		    // Initial overlap
-		    return output;
+		    return;
 	    }
 
 	    // Prepare output.
@@ -591,7 +598,6 @@ public sealed partial class RayCastSystem
 	    output.Fraction = lambda;
 	    output.Iterations = iter;
 	    output.Hit = true;
-	    return output;
     }
 
     private int FindSupport(DistanceProxy proxy, Vector2 direction)
@@ -613,9 +619,14 @@ public sealed partial class RayCastSystem
 
     private CastOutput ShapeCastCircle(ShapeCastInput input, PhysShapeCircle shape)
     {
+        Span<Vector2> proxyAVerts = new[]
+        {
+            shape.Position,
+        };
+
         var pairInput = new ShapeCastPairInput
         {
-            ProxyA = DistanceProxy.MakeProxy([shape.Position], 1, shape.Radius ),
+            ProxyA = DistanceProxy.MakeProxy(proxyAVerts, 1, shape.Radius ),
             ProxyB = DistanceProxy.MakeProxy(input.Points, input.Count, input.Radius ),
             TransformA = Physics.Transform.Empty,
             TransformB = Physics.Transform.Empty,
@@ -623,7 +634,8 @@ public sealed partial class RayCastSystem
             MaxFraction = input.MaxFraction
         };
 
-        var output = ShapeCast(pairInput);
+        var output = new CastOutput();
+        ShapeCast(ref output, pairInput);
         return output;
     }
 
@@ -631,7 +643,7 @@ public sealed partial class RayCastSystem
     {
         var pairInput = new ShapeCastPairInput
         {
-            ProxyA = DistanceProxy.MakeProxy(shape.Vertices, shape.VertexCount, shape.Radius),
+            ProxyA = DistanceProxy.MakeProxy(shape._vertices.AsSpan, shape.VertexCount, shape.Radius),
             ProxyB = DistanceProxy.MakeProxy(input.Points, input.Count, input.Radius),
             TransformA = Physics.Transform.Empty,
             TransformB = Physics.Transform.Empty,
@@ -639,21 +651,30 @@ public sealed partial class RayCastSystem
             MaxFraction = input.MaxFraction
         };
 
-        var output = ShapeCast(pairInput);
+        var output = new CastOutput();
+        ShapeCast(ref output, pairInput);
         return output;
     }
 
     private CastOutput ShapeCastSegment(ShapeCastInput input, EdgeShape shape)
     {
-        var pairInput = new ShapeCastPairInput();
-        pairInput.ProxyA = DistanceProxy.MakeProxy([shape.Vertex0], 2, 0.0f);
-        pairInput.ProxyB = DistanceProxy.MakeProxy(input.Points, input.Count, input.Radius);
-        pairInput.TransformA = Physics.Transform.Empty;
-        pairInput.TransformB = Physics.Transform.Empty;
-        pairInput.TranslationB = input.Translation;
-        pairInput.MaxFraction = input.MaxFraction;
+        Span<Vector2> proxyAVerts = new[]
+        {
+            shape.Vertex0,
+        };
 
-        var output = ShapeCast(pairInput);
+        var pairInput = new ShapeCastPairInput
+        {
+            ProxyA = DistanceProxy.MakeProxy(proxyAVerts, 2, 0.0f),
+            ProxyB = DistanceProxy.MakeProxy(input.Points, input.Count, input.Radius),
+            TransformA = Physics.Transform.Empty,
+            TransformB = Physics.Transform.Empty,
+            TranslationB = input.Translation,
+            MaxFraction = input.MaxFraction
+        };
+
+        var output = new CastOutput();
+        ShapeCast(ref output, pairInput);
         return output;
     }
 

Robust.Shared/Physics/Systems/RayCastSystem.cs

@@ -275,6 +275,9 @@ public sealed partial class RayCastSystem : EntitySystem
             case PhysShapeCircle circle:
                 CastCircle(entity, ref result, circle, originTransform, translation, filter, callback);
                 break;
+            case SlimPolygon slim:
+                CastPolygon(entity, ref result, new PolygonShape(slim), originTransform, translation, filter, callback);
+                break;
             case Polygon poly:
                 CastPolygon(entity, ref result, new PolygonShape(poly), originTransform, translation, filter, callback);
                 break;

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

@@ -113,10 +113,7 @@ public abstract partial class SharedPhysicsSystem
 #if DEBUG
             contact._debugPhysics = _debugPhysicsSystem;
 #endif
-            contact.Manifold = new Manifold
-            {
-                Points = new ManifoldPoint[2]
-            };
+            contact.Manifold = new Manifold();
 
             return contact;
         }

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

@@ -1026,12 +1026,6 @@ public abstract partial class SharedPhysicsSystem
             var angle = angles[offset + i];
             var xform = xformQuery.GetComponent(uid);
 
-            // Temporary NaN guards until PVS is fixed.
-            if (!float.IsNaN(position.X) && !float.IsNaN(position.Y))
-            {
-                _transform.SetLocalPositionRotation(xform, xform.LocalPosition + position, xform.LocalRotation + angle);
-            }
-
             var linVelocity = linearVelocities[offset + i];
             var physicsDirtied = false;
 
@@ -1047,6 +1041,13 @@ public abstract partial class SharedPhysicsSystem
                 physicsDirtied |= SetAngularVelocity(uid, angVelocity, false, body: body);
             }
 
+            // Temporary NaN guards until PVS is fixed.
+            // May reparent object and change body's velocity.
+            if (!float.IsNaN(position.X) && !float.IsNaN(position.Y))
+            {
+                _transform.SetLocalPositionRotation(xform, xform.LocalPosition + position, xform.LocalRotation + angle);
+            }
+
             if (physicsDirtied)
                 Dirty(uid, body);
         }

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

@@ -1,55 +0,0 @@
-using System.Buffers;
-using System.Numerics;
-using Microsoft.Extensions.ObjectPool;
-using Robust.Shared.Maths;
-using Robust.Shared.Physics.Shapes;
-
-namespace Robust.Shared.Physics.Systems;
-
-public abstract partial class SharedPhysicsSystem
-{
-    /// <summary>
-    /// Gets a polygon with pooled arrays backing it.
-    /// </summary>
-    internal Polygon GetPooled(Box2 box)
-    {
-        var vertices = ArrayPool<Vector2>.Shared.Rent(4);
-        var normals = ArrayPool<Vector2>.Shared.Rent(4);
-        var centroid = box.Center;
-
-        vertices[0] = box.BottomLeft;
-        vertices[1] = box.BottomRight;
-        vertices[2] = box.TopRight;
-        vertices[3] = box.TopLeft;
-
-        normals[0] = new Vector2(0.0f, -1.0f);
-        normals[1] = new Vector2(1.0f, 0.0f);
-        normals[2] = new Vector2(0.0f, 1.0f);
-        normals[3] = new Vector2(-1.0f, 0.0f);
-
-        return new Polygon(vertices, normals, centroid, 4);
-    }
-
-    internal Polygon GetPooled(Box2Rotated box)
-    {
-        var vertices = ArrayPool<Vector2>.Shared.Rent(4);
-        var normals = ArrayPool<Vector2>.Shared.Rent(4);
-        var centroid = box.Center;
-
-        vertices[0] = box.BottomLeft;
-        vertices[1] = box.BottomRight;
-        vertices[2] = box.TopRight;
-        vertices[3] = box.TopLeft;
-
-        var polygon = new Polygon(vertices, normals, centroid, 4);
-        polygon.CalculateNormals(normals, 4);
-
-        return polygon;
-    }
-
-    internal void ReturnPooled(Polygon polygon)
-    {
-        ArrayPool<Vector2>.Shared.Return(polygon.Vertices);
-        ArrayPool<Vector2>.Shared.Return(polygon.Normals);
-    }
-}

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

@@ -67,7 +67,6 @@ public abstract partial class SharedPhysicsSystem
             velocityConstraint.TangentSpeed = contact.TangentSpeed;
             velocityConstraint.IndexA = bodyA.IslandIndex[island.Index];
             velocityConstraint.IndexB = bodyB.IslandIndex[island.Index];
-            Array.Resize(ref velocityConstraint.Points, 2);
             // Don't need to reset point data as it all gets set below.
 
             var (invMassA, invMassB) = GetInvMass(bodyA, bodyB);
@@ -87,7 +86,6 @@ public abstract partial class SharedPhysicsSystem
             (positionConstraint.InvMassA, positionConstraint.InvMassB) = (invMassA, invMassB);
             positionConstraint.LocalCenterA = bodyA.LocalCenter;
             positionConstraint.LocalCenterB = bodyB.LocalCenter;
-            Array.Resize(ref positionConstraint.LocalPoints, 2);
 
             positionConstraint.InvIA = bodyA.InvI;
             positionConstraint.InvIB = bodyB.InvI;
@@ -97,11 +95,14 @@ public abstract partial class SharedPhysicsSystem
             positionConstraint.RadiusA = radiusA;
             positionConstraint.RadiusB = radiusB;
             positionConstraint.Type = manifold.Type;
+            var points = manifold.Points.AsSpan;
+            var posPoints = positionConstraint.LocalPoints.AsSpan;
+            var velPoints = velocityConstraint.Points.AsSpan;
 
             for (var j = 0; j < pointCount; ++j)
             {
-                var contactPoint = manifold.Points[j];
-                ref var constraintPoint = ref velocityConstraint.Points[j];
+                var contactPoint = points[j];
+                ref var constraintPoint = ref velPoints[j];
 
                 if (_warmStarting)
                 {
@@ -120,7 +121,7 @@ public abstract partial class SharedPhysicsSystem
                 constraintPoint.TangentMass = 0.0f;
                 constraintPoint.VelocityBias = 0.0f;
 
-                positionConstraint.LocalPoints[j] = contactPoint.LocalPoint;
+                posPoints[j] = contactPoint.LocalPoint;
             }
         }
     }
@@ -220,10 +221,11 @@ public abstract partial class SharedPhysicsSystem
             velocityConstraint.Normal = normal;
 
             int pointCount = velocityConstraint.PointCount;
+            var velPoints = velocityConstraint.Points.AsSpan;
 
             for (int j = 0; j < pointCount; ++j)
             {
-                ref var vcp = ref velocityConstraint.Points[j];
+                ref var vcp = ref velPoints[j];
 
                 vcp.RelativeVelocityA = points[j] - centerA;
                 vcp.RelativeVelocityB = points[j] - centerB;
@@ -256,8 +258,8 @@ public abstract partial class SharedPhysicsSystem
             // If we have two points, then prepare the block solver.
             if (velocityConstraint.PointCount == 2)
             {
-                var vcp1 = velocityConstraint.Points[0];
-                var vcp2 = velocityConstraint.Points[1];
+                var vcp1 = velocityConstraint.Points._00;
+                var vcp2 = velocityConstraint.Points._01;
 
                 var rn1A = Vector2Helpers.Cross(vcp1.RelativeVelocityA, velocityConstraint.Normal);
                 var rn1B = Vector2Helpers.Cross(vcp1.RelativeVelocityB, velocityConstraint.Normal);
@@ -299,6 +301,7 @@ public abstract partial class SharedPhysicsSystem
         for (var i = 0; i < island.Contacts.Count; ++i)
         {
             var velocityConstraint = velocityConstraints[i];
+            var velPoints = velocityConstraint.Points.AsSpan;
 
             var indexA = velocityConstraint.IndexA;
             var indexB = velocityConstraint.IndexB;
@@ -318,7 +321,7 @@ public abstract partial class SharedPhysicsSystem
 
             for (var j = 0; j < pointCount; ++j)
             {
-                var constraintPoint = velocityConstraint.Points[j];
+                var constraintPoint = velPoints[j];
                 var P = normal * constraintPoint.NormalImpulse + tangent * constraintPoint.TangentImpulse;
                 angVelocityA -= invIA * Vector2Helpers.Cross(constraintPoint.RelativeVelocityA, P);
                 linVelocityA -= P * invMassA;
@@ -386,12 +389,13 @@ public abstract partial class SharedPhysicsSystem
             var friction = velocityConstraint.Friction;
 
             DebugTools.Assert(pointCount is 1 or 2);
+            var velPoints = velocityConstraint.Points.AsSpan;
 
             // Solve tangent constraints first because non-penetration is more important
             // than friction.
             for (var j = 0; j < pointCount; ++j)
             {
-                ref var velConstraintPoint = ref velocityConstraint.Points[j];
+                ref var velConstraintPoint = ref velPoints[j];
 
                 // Relative velocity at contact
                 var dv = vB + Vector2Helpers.Cross(wB, velConstraintPoint.RelativeVelocityB) - vA - Vector2Helpers.Cross(wA, velConstraintPoint.RelativeVelocityA);
@@ -419,7 +423,7 @@ public abstract partial class SharedPhysicsSystem
             // Solve normal constraints
             if (velocityConstraint.PointCount == 1)
             {
-                ref var vcp = ref velocityConstraint.Points[0];
+                ref var vcp = ref velocityConstraint.Points._00;
 
                 // Relative velocity at contact
                 Vector2 dv = vB + Vector2Helpers.Cross(wB, vcp.RelativeVelocityB) - vA - Vector2Helpers.Cross(wA, vcp.RelativeVelocityA);
@@ -476,8 +480,8 @@ public abstract partial class SharedPhysicsSystem
                 //    = A * x + b'
                 // b' = b - A * a;
 
-                ref var cp1 = ref velocityConstraint.Points[0];
-                ref var cp2 = ref velocityConstraint.Points[1];
+                ref var cp1 = ref velocityConstraint.Points._00;
+                ref var cp2 = ref velocityConstraint.Points._01;
 
                 Vector2 a = new Vector2(cp1.NormalImpulse, cp2.NormalImpulse);
                 DebugTools.Assert(a.X >= 0.0f && a.Y >= 0.0f);
@@ -643,14 +647,16 @@ public abstract partial class SharedPhysicsSystem
     {
         for (var i = 0; i < island.Contacts.Count; ++i)
         {
-            ContactVelocityConstraint velocityConstraint = velocityConstraints[i];
+            var velocityConstraint = velocityConstraints[i];
             ref var manifold = ref island.Contacts[velocityConstraint.ContactIndex].Manifold;
+            var manPoints = manifold.Points.AsSpan;
+            var velPoints = velocityConstraint.Points.AsSpan;
 
             for (var j = 0; j < velocityConstraint.PointCount; ++j)
             {
-                ref var point = ref manifold.Points[j];
-                point.NormalImpulse = velocityConstraint.Points[j].NormalImpulse;
-                point.TangentImpulse = velocityConstraint.Points[j].TangentImpulse;
+                ref var point = ref manPoints[j];
+                point.NormalImpulse = velPoints[j].NormalImpulse;
+                point.TangentImpulse = velPoints[j].TangentImpulse;
             }
         }
     }
@@ -794,7 +800,7 @@ public abstract partial class SharedPhysicsSystem
             {
                 normal = new Vector2(1.0f, 0.0f);
                 Vector2 pointA = Physics.Transform.Mul(xfA, manifold.LocalPoint);
-                Vector2 pointB = Physics.Transform.Mul(xfB, manifold.Points[0].LocalPoint);
+                Vector2 pointB = Physics.Transform.Mul(xfB, manifold.Points._00.LocalPoint);
 
                 if ((pointA - pointB).LengthSquared() > float.Epsilon * float.Epsilon)
                 {
@@ -812,10 +818,11 @@ public abstract partial class SharedPhysicsSystem
             {
                 normal = Physics.Transform.Mul(xfA.Quaternion2D, manifold.LocalNormal);
                 Vector2 planePoint = Physics.Transform.Mul(xfA, manifold.LocalPoint);
+                var manPoints = manifold.Points.AsSpan;
 
                 for (int i = 0; i < manifold.PointCount; ++i)
                 {
-                    Vector2 clipPoint = Physics.Transform.Mul(xfB, manifold.Points[i].LocalPoint);
+                    Vector2 clipPoint = Physics.Transform.Mul(xfB, manPoints[i].LocalPoint);
                     Vector2 cA = clipPoint + normal * (radiusA - Vector2.Dot(clipPoint - planePoint, normal));
                     Vector2 cB = clipPoint - normal * radiusB;
                     points[i] = (cA + cB) * 0.5f;
@@ -827,10 +834,11 @@ public abstract partial class SharedPhysicsSystem
             {
                 normal = Physics.Transform.Mul(xfB.Quaternion2D, manifold.LocalNormal);
                 Vector2 planePoint = Physics.Transform.Mul(xfB, manifold.LocalPoint);
+                var manPoints = manifold.Points.AsSpan;
 
                 for (int i = 0; i < manifold.PointCount; ++i)
                 {
-                    Vector2 clipPoint = Physics.Transform.Mul(xfA, manifold.Points[i].LocalPoint);
+                    Vector2 clipPoint = Physics.Transform.Mul(xfA, manPoints[i].LocalPoint);
                     Vector2 cB = clipPoint + normal * (radiusB - Vector2.Dot(clipPoint - planePoint, normal));
                     Vector2 cA = clipPoint - normal * radiusA;
                     points[i] = (cA + cB) * 0.5f;
@@ -863,7 +871,7 @@ public abstract partial class SharedPhysicsSystem
                 case ManifoldType.Circles:
                     {
                         Vector2 pointA = Physics.Transform.Mul(xfA, pc.LocalPoint);
-                        Vector2 pointB = Physics.Transform.Mul(xfB, pc.LocalPoints[0]);
+                        Vector2 pointB = Physics.Transform.Mul(xfB, pc.LocalPoints._00);
                         normal = pointB - pointA;
 
                         //FPE: Fix to handle zero normalization
@@ -877,10 +885,11 @@ public abstract partial class SharedPhysicsSystem
 
                 case ManifoldType.FaceA:
                     {
+                        var pcPoints = pc.LocalPoints.AsSpan;
                         normal = Physics.Transform.Mul(xfA.Quaternion2D, pc.LocalNormal);
                         Vector2 planePoint = Physics.Transform.Mul(xfA, pc.LocalPoint);
 
-                        Vector2 clipPoint = Physics.Transform.Mul(xfB, pc.LocalPoints[index]);
+                        Vector2 clipPoint = Physics.Transform.Mul(xfB, pcPoints[index]);
                         separation = Vector2.Dot(clipPoint - planePoint, normal) - pc.RadiusA - pc.RadiusB;
                         point = clipPoint;
                     }
@@ -888,10 +897,11 @@ public abstract partial class SharedPhysicsSystem
 
                 case ManifoldType.FaceB:
                     {
+                        var pcPoints = pc.LocalPoints.AsSpan;
                         normal = Physics.Transform.Mul(xfB.Quaternion2D, pc.LocalNormal);
                         Vector2 planePoint = Physics.Transform.Mul(xfB, pc.LocalPoint);
 
-                        Vector2 clipPoint = Physics.Transform.Mul(xfA, pc.LocalPoints[index]);
+                        Vector2 clipPoint = Physics.Transform.Mul(xfA, pcPoints[index]);
                         separation = Vector2.Dot(clipPoint - planePoint, normal) - pc.RadiusA - pc.RadiusB;
                         point = clipPoint;
 

Robust.Shared/Prototypes/EntityCategoryPrototype.cs

@@ -9,7 +9,7 @@ namespace Robust.Shared.Prototypes;
 /// Prototype that represents some entity prototype category.
 /// Useful for sorting or grouping entity prototypes for mapping/spawning UIs.
 /// </summary>
-[Prototype("entityCategory")]
+[Prototype]
 public sealed partial class EntityCategoryPrototype : IPrototype
 {
     [IdDataField] public string ID { get; private set; } = default!;