Fix box2 serializer (#1966)

There's some existing content with invalid bounds so this is going to be fun.

.gitmodules

@@ -16,3 +16,6 @@
 [submodule "Linguini"]
 	path = Linguini
 	url = https://github.com/space-wizards/Linguini
+[submodule "cefglue"]
+	path = cefglue
+	url = https://gitlab.com/xiliumhq/chromiumembedded/cefglue/

OpenToolkit.GraphicsLibraryFramework/Enums/WindowHintBool.cs

@@ -129,5 +129,7 @@ namespace OpenToolkit.GraphicsLibraryFramework
         /// for controlling sRGB rendering and a created OpenGL ES context will always have sRGB rendering enabled.
         /// </summary>
         SrgbCapable = 0x0002100E,
+
+        ScaleToMonitor = 0x0002200C,
     }
 }

OpenToolkit.GraphicsLibraryFramework/GLFW.cs

@@ -5551,5 +5551,10 @@ namespace OpenToolkit.GraphicsLibraryFramework
         {
             return glfwGetX11Window(window);
         }
+
+        public static unsafe IntPtr GetWin32Window(Window* window)
+        {
+            return glfwGetWin32Window(window);
+        }
     }
 }

OpenToolkit.GraphicsLibraryFramework/GLFWNative.cs

@@ -406,5 +406,8 @@ namespace OpenToolkit.GraphicsLibraryFramework
 
         [DllImport(LibraryName)]
         public static extern uint glfwGetX11Window(Window* window);
+
+        [DllImport(LibraryName)]
+        public static extern IntPtr glfwGetWin32Window(Window* window);
     }
 }

Robust.Analyzers/FriendAnalyzer.cs

@@ -0,0 +1,107 @@
+using System.Collections.Immutable;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Diagnostics;
+
+namespace Robust.Analyzers
+{
+    [DiagnosticAnalyzer(LanguageNames.CSharp)]
+    public class FriendAnalyzer : DiagnosticAnalyzer
+    {
+        const string FriendAttribute = "Robust.Shared.Analyzers.FriendAttribute";
+
+        public const string DiagnosticId = "RA0002";
+
+        private const string Title = "Tried to access friend-only member";
+        private const string MessageFormat = "Tried to access member \"{0}\" in class \"{1}\" which can only be accessed by friend classes";
+        private const string Description = "Make sure to specify the accessing class in the friends attribute.";
+        private const string Category = "Usage";
+
+        [SuppressMessage("ReSharper", "RS2008")]
+        private static readonly DiagnosticDescriptor Rule = new (DiagnosticId, Title, MessageFormat, Category, DiagnosticSeverity.Error, true, Description);
+
+        public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics => ImmutableArray.Create(Rule);
+
+        public override void Initialize(AnalysisContext context)
+        {
+            context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.Analyze | GeneratedCodeAnalysisFlags.ReportDiagnostics);
+            context.EnableConcurrentExecution();
+            context.RegisterSyntaxNodeAction(CheckFriendship, SyntaxKind.SimpleMemberAccessExpression);
+        }
+
+        private void CheckFriendship(SyntaxNodeAnalysisContext context)
+        {
+            if (context.Node is not MemberAccessExpressionSyntax memberAccess)
+                return;
+
+            // We only do something if our parent is one of a few types.
+            switch (context.Node.Parent)
+            {
+                // If we're being assigned...
+                case AssignmentExpressionSyntax assignParent:
+                {
+                    if (assignParent.Left != memberAccess)
+                        return;
+                    break;
+                }
+
+                // If we're being invoked...
+                case InvocationExpressionSyntax:
+                    break;
+
+                // Otherwise, do nothing.
+                default:
+                    return;
+            }
+
+            // Get the friend attribute
+            var friendAttr = context.Compilation.GetTypeByMetadataName(FriendAttribute);
+
+            // Get the type that is containing this expression, or, the class where this is happening.
+            if (context.ContainingSymbol?.ContainingType is not { } containingType)
+                return;
+
+            // We check all of our children and get only the identifiers.
+            foreach (var identifier in memberAccess.ChildNodes().Select(node => node as IdentifierNameSyntax))
+            {
+                if (identifier == null) continue;
+
+                // Get the type info of the identifier, so we can check the attributes...
+                if (context.SemanticModel.GetTypeInfo(identifier).ConvertedType is not { } type)
+                    continue;
+
+                // Same-type access is always fine.
+                if (SymbolEqualityComparer.Default.Equals(type, containingType))
+                    continue;
+
+                // Finally, get all attributes of the type, to check if we have any friend classes.
+                foreach (var attribute in type.GetAttributes())
+                {
+                    // If the attribute isn't the friend attribute, continue.
+                    if (!SymbolEqualityComparer.Default.Equals(attribute.AttributeClass, friendAttr))
+                        continue;
+
+                    // Check all types allowed in the friend attribute. (We assume there's only one constructor arg.)
+                    foreach (var constant in attribute.ConstructorArguments[0].Values)
+                    {
+                        // Check if the value is a type...
+                        if (constant.Value is not INamedTypeSymbol t)
+                            continue;
+
+                        // If we find that the containing class is specified in the attribute, return! All is good.
+                        if (SymbolEqualityComparer.Default.Equals(containingType, t))
+                            return;
+                    }
+
+                    // Not in a friend class! Report an error.
+                    context.ReportDiagnostic(
+                        Diagnostic.Create(Rule, context.Node.GetLocation(),
+                            $"{context.Node.ToString().Split('.').LastOrDefault()}", $"{type.Name}"));
+                }
+            }
+        }
+    }
+}

Robust.Analyzers/Robust.Analyzers.csproj

@@ -2,6 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
+    <LangVersion>9</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>

Robust.Benchmarks/NumericsHelpers/AddBenchmark.cs

@@ -0,0 +1,28 @@
+using BenchmarkDotNet.Attributes;
+
+namespace Robust.Benchmarks.NumericsHelpers
+{
+    public class AddBenchmark
+    {
+        [Params(32, 128)]
+        public int N { get; set; }
+
+        private float[] _inputA = default!;
+        private float[] _inputB = default!;
+        private float[] _output = default!;
+
+        [GlobalSetup]
+        public void Setup()
+        {
+            _inputA = new float[N];
+            _inputB = new float[N];
+            _output = new float[N];
+        }
+
+        [Benchmark]
+        public void Bench()
+        {
+            Shared.Maths.NumericsHelpers.Add(_inputA, _inputB, _output);
+        }
+    }
+}

Robust.Benchmarks/Program.cs

@@ -6,7 +6,7 @@ namespace Robust.Benchmarks
     {
         public static void Main(string[] args)
         {
-            BenchmarkSwitcher.FromAssembly(typeof(Program).Assembly).Run();
+            BenchmarkSwitcher.FromAssembly(typeof(Program).Assembly).Run(args);
         }
     }
 }

Robust.Benchmarks/Serialization/Copy/SerializationCopyBenchmark.cs

@@ -6,6 +6,7 @@ using Robust.Shared.Serialization.Manager;
 using Robust.Shared.Serialization.Markdown;
 using Robust.Shared.Serialization.Markdown.Mapping;
 using Robust.Shared.Serialization.Markdown.Sequence;
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom;
 using Robust.Shared.Utility;
 using YamlDotNet.RepresentationModel;
 
@@ -35,6 +36,10 @@ namespace Robust.Benchmarks.Serialization.Copy
 
         private SeedDataDefinition Seed { get; }
 
+        private BenchmarkFlagsEnum FlagZero = BenchmarkFlagsEnum.Zero;
+
+        private BenchmarkFlagsEnum FlagThirtyOne = BenchmarkFlagsEnum.ThirtyOne;
+
         [Benchmark]
         public string? CreateCopyString()
         {
@@ -111,5 +116,25 @@ namespace Robust.Benchmarks.Serialization.Copy
 
             return copy;
         }
+
+        [Benchmark]
+        [BenchmarkCategory("flag")]
+        public object? CreateCopyFlagZero()
+        {
+            return SerializationManager.CopyWithTypeSerializer(
+                typeof(FlagSerializer<BenchmarkFlags>),
+                (int) FlagZero,
+                (int) FlagZero);
+        }
+
+        [Benchmark]
+        [BenchmarkCategory("flag")]
+        public object? CreateCopyFlagThirtyOne()
+        {
+            return SerializationManager.CopyWithTypeSerializer(
+                typeof(FlagSerializer<BenchmarkFlags>),
+                (int) FlagThirtyOne,
+                (int) FlagThirtyOne);
+        }
     }
 }

Robust.Benchmarks/Serialization/Definitions/BenchmarkFlags.cs

@@ -0,0 +1,19 @@
+using System;
+using Robust.Shared.Serialization;
+
+namespace Robust.Benchmarks.Serialization.Definitions
+{
+    public class BenchmarkFlags
+    {
+        public const int Zero = 1 << 0;
+        public const int ThirtyOne = 1 << 31;
+    }
+
+    [Flags]
+    [FlagsFor(typeof(BenchmarkFlags))]
+    public enum BenchmarkFlagsEnum
+    {
+        Zero = BenchmarkFlags.Zero,
+        ThirtyOne = BenchmarkFlags.ThirtyOne
+    }
+}

Robust.Benchmarks/Serialization/Read/SerializationReadBenchmark.cs

@@ -1,10 +1,12 @@
 using System.IO;
 using BenchmarkDotNet.Attributes;
 using Robust.Benchmarks.Serialization.Definitions;
+using Robust.Shared.Serialization.Manager.Result;
 using Robust.Shared.Serialization.Markdown;
 using Robust.Shared.Serialization.Markdown.Mapping;
 using Robust.Shared.Serialization.Markdown.Sequence;
 using Robust.Shared.Serialization.Markdown.Value;
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom;
 using YamlDotNet.RepresentationModel;
 
 namespace Robust.Benchmarks.Serialization.Read
@@ -32,6 +34,10 @@ namespace Robust.Benchmarks.Serialization.Read
 
         private MappingDataNode SeedNode { get; }
 
+        private ValueDataNode FlagZero { get; } = new("Zero");
+
+        private ValueDataNode FlagThirtyOne { get; } = new("ThirtyOne");
+
         [Benchmark]
         public string? ReadString()
         {
@@ -55,5 +61,25 @@ namespace Robust.Benchmarks.Serialization.Read
         {
             return SerializationManager.ReadValue<SeedDataDefinition>(SeedNode);
         }
+
+        [Benchmark]
+        [BenchmarkCategory("flag")]
+        public DeserializationResult ReadFlagZero()
+        {
+            return SerializationManager.ReadWithTypeSerializer(
+                typeof(int),
+                typeof(FlagSerializer<BenchmarkFlags>),
+                FlagZero);
+        }
+
+        [Benchmark]
+        [BenchmarkCategory("flag")]
+        public DeserializationResult ReadThirtyOne()
+        {
+            return SerializationManager.ReadWithTypeSerializer(
+                typeof(int),
+                typeof(FlagSerializer<BenchmarkFlags>),
+                FlagThirtyOne);
+        }
     }
 }

Robust.Benchmarks/Serialization/Write/SerializationWriteBenchmark.cs

@@ -7,6 +7,7 @@ using Robust.Shared.Serialization.Markdown;
 using Robust.Shared.Serialization.Markdown.Mapping;
 using Robust.Shared.Serialization.Markdown.Sequence;
 using Robust.Shared.Serialization.Markdown.Value;
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom;
 using YamlDotNet.RepresentationModel;
 
 namespace Robust.Benchmarks.Serialization.Write
@@ -35,6 +36,10 @@ namespace Robust.Benchmarks.Serialization.Write
 
         private SeedDataDefinition Seed { get; }
 
+        private BenchmarkFlagsEnum FlagZero = BenchmarkFlagsEnum.Zero;
+
+        private BenchmarkFlagsEnum FlagThirtyOne = BenchmarkFlagsEnum.ThirtyOne;
+
         [Benchmark]
         public DataNode WriteString()
         {
@@ -94,5 +99,25 @@ namespace Robust.Benchmarks.Serialization.Write
 
             return mapping;
         }
+
+        [Benchmark]
+        [BenchmarkCategory("flag")]
+        public DataNode WriteFlagZero()
+        {
+            return SerializationManager.WriteWithTypeSerializer(
+                typeof(int),
+                typeof(FlagSerializer<BenchmarkFlags>),
+                FlagZero);
+        }
+
+        [Benchmark]
+        [BenchmarkCategory("flag")]
+        public DataNode WriteThirtyOne()
+        {
+            return SerializationManager.WriteWithTypeSerializer(
+                typeof(int),
+                typeof(FlagSerializer<BenchmarkFlags>),
+                FlagThirtyOne);
+        }
     }
 }

Robust.Client.CEF/BeforeBrowseContext.cs

@@ -0,0 +1,32 @@
+using Xilium.CefGlue;
+
+namespace Robust.Client.CEF
+{
+    public sealed class BeforeBrowseContext
+    {
+        internal readonly CefRequest CefRequest;
+
+        public string Url => CefRequest.Url;
+        public string Method => CefRequest.Method;
+
+        public bool IsRedirect { get; }
+        public bool UserGesture { get; }
+
+        public bool IsCancelled { get; private set; }
+
+        internal BeforeBrowseContext(
+            bool isRedirect,
+            bool userGesture,
+            CefRequest cefRequest)
+        {
+            CefRequest = cefRequest;
+            IsRedirect = isRedirect;
+            UserGesture = userGesture;
+        }
+
+        public void DoCancel()
+        {
+            IsCancelled = true;
+        }
+    }
+}

Robust.Client.CEF/BrowserControl.cs

@@ -0,0 +1,593 @@
+using System;
+using System.Collections.Generic;
+using Robust.Client.Graphics;
+using Robust.Client.Input;
+using Robust.Client.UserInterface;
+using Robust.Shared.IoC;
+using Robust.Shared.Log;
+using Robust.Shared.Maths;
+using Robust.Shared.Utility;
+using Robust.Shared.ViewVariables;
+using SixLabors.ImageSharp.PixelFormats;
+using Xilium.CefGlue;
+using static Robust.Client.CEF.CefKeyCodes;
+using static Robust.Client.CEF.CefKeyCodes.ChromiumKeyboardCode;
+using static Robust.Client.Input.Keyboard;
+
+namespace Robust.Client.CEF
+{
+    // Funny browser control to integrate in UI.
+    public class BrowserControl : Control, IBrowserControl, IRawInputControl
+    {
+        private const int ScrollSpeed = 50;
+
+        [Dependency] private readonly IClyde _clyde = default!;
+        [Dependency] private readonly IInputManager _inputMgr = default!;
+        [Dependency] private readonly CefManager _cef = default!;
+
+        private RobustRequestHandler _requestHandler = new RobustRequestHandler(Logger.GetSawmill("root"));
+        private LiveData? _data;
+        private string _startUrl = "about:blank";
+
+        [ViewVariables(VVAccess.ReadWrite)]
+        public string Url
+        {
+            get => _data == null ? _startUrl : _data.Browser.GetMainFrame().Url;
+            set
+            {
+                if (_data == null)
+                    _startUrl = value;
+                else
+                    _data.Browser.GetMainFrame().LoadUrl(value);
+            }
+        }
+
+        [ViewVariables] public bool IsLoading => _data?.Browser.IsLoading ?? false;
+
+        private readonly Dictionary<Key, ChromiumKeyboardCode> _keyMap = new()
+        {
+            [Key.A] = VKEY_A,
+            [Key.B] = VKEY_B,
+            [Key.C] = VKEY_C,
+            [Key.D] = VKEY_D,
+            [Key.E] = VKEY_E,
+            [Key.F] = VKEY_F,
+            [Key.G] = VKEY_G,
+            [Key.H] = VKEY_H,
+            [Key.I] = VKEY_I,
+            [Key.J] = VKEY_J,
+            [Key.K] = VKEY_K,
+            [Key.L] = VKEY_L,
+            [Key.M] = VKEY_M,
+            [Key.N] = VKEY_N,
+            [Key.O] = VKEY_O,
+            [Key.P] = VKEY_P,
+            [Key.Q] = VKEY_Q,
+            [Key.R] = VKEY_R,
+            [Key.S] = VKEY_S,
+            [Key.T] = VKEY_T,
+            [Key.U] = VKEY_U,
+            [Key.V] = VKEY_V,
+            [Key.W] = VKEY_W,
+            [Key.X] = VKEY_X,
+            [Key.Y] = VKEY_Y,
+            [Key.Z] = VKEY_Z,
+            [Key.Num0] = VKEY_0,
+            [Key.Num1] = VKEY_1,
+            [Key.Num2] = VKEY_2,
+            [Key.Num3] = VKEY_3,
+            [Key.Num4] = VKEY_4,
+            [Key.Num5] = VKEY_5,
+            [Key.Num6] = VKEY_6,
+            [Key.Num7] = VKEY_7,
+            [Key.Num8] = VKEY_8,
+            [Key.Num9] = VKEY_9,
+            [Key.NumpadNum0] = VKEY_NUMPAD0,
+            [Key.NumpadNum1] = VKEY_NUMPAD1,
+            [Key.NumpadNum2] = VKEY_NUMPAD2,
+            [Key.NumpadNum3] = VKEY_NUMPAD3,
+            [Key.NumpadNum4] = VKEY_NUMPAD4,
+            [Key.NumpadNum5] = VKEY_NUMPAD5,
+            [Key.NumpadNum6] = VKEY_NUMPAD6,
+            [Key.NumpadNum7] = VKEY_NUMPAD7,
+            [Key.NumpadNum8] = VKEY_NUMPAD8,
+            [Key.NumpadNum9] = VKEY_NUMPAD9,
+            [Key.Escape] = VKEY_ESCAPE,
+            [Key.Control] = VKEY_CONTROL,
+            [Key.Shift] = VKEY_SHIFT,
+            [Key.Alt] = VKEY_MENU,
+            [Key.LSystem] = VKEY_LWIN,
+            [Key.RSystem] = VKEY_RWIN,
+            [Key.LBracket] = VKEY_OEM_4,
+            [Key.RBracket] = VKEY_OEM_6,
+            [Key.SemiColon] = VKEY_OEM_1,
+            [Key.Comma] = VKEY_OEM_COMMA,
+            [Key.Period] = VKEY_OEM_PERIOD,
+            [Key.Apostrophe] = VKEY_OEM_7,
+            [Key.Slash] = VKEY_OEM_2,
+            [Key.BackSlash] = VKEY_OEM_5,
+            [Key.Tilde] = VKEY_OEM_3,
+            [Key.Equal] = VKEY_OEM_PLUS,
+            [Key.Space] = VKEY_SPACE,
+            [Key.Return] = VKEY_RETURN,
+            [Key.BackSpace] = VKEY_BACK,
+            [Key.Tab] = VKEY_TAB,
+            [Key.PageUp] = VKEY_PRIOR,
+            [Key.PageDown] = VKEY_NEXT,
+            [Key.End] = VKEY_END,
+            [Key.Home] = VKEY_HOME,
+            [Key.Insert] = VKEY_INSERT,
+            [Key.Delete] = VKEY_DELETE,
+            [Key.Minus] = VKEY_OEM_MINUS,
+            [Key.NumpadAdd] = VKEY_ADD,
+            [Key.NumpadSubtract] = VKEY_SUBTRACT,
+            [Key.NumpadDivide] = VKEY_DIVIDE,
+            [Key.NumpadMultiply] = VKEY_MULTIPLY,
+            [Key.NumpadDecimal] = VKEY_DECIMAL,
+            [Key.Left] = VKEY_LEFT,
+            [Key.Right] = VKEY_RIGHT,
+            [Key.Up] = VKEY_UP,
+            [Key.Down] = VKEY_DOWN,
+            [Key.F1] = VKEY_F1,
+            [Key.F2] = VKEY_F2,
+            [Key.F3] = VKEY_F3,
+            [Key.F4] = VKEY_F4,
+            [Key.F5] = VKEY_F5,
+            [Key.F6] = VKEY_F6,
+            [Key.F7] = VKEY_F7,
+            [Key.F8] = VKEY_F8,
+            [Key.F9] = VKEY_F9,
+            [Key.F10] = VKEY_F10,
+            [Key.F11] = VKEY_F11,
+            [Key.F12] = VKEY_F12,
+            [Key.F13] = VKEY_F13,
+            [Key.F14] = VKEY_F14,
+            [Key.F15] = VKEY_F15,
+            [Key.Pause] = VKEY_PAUSE,
+        };
+
+        public BrowserControl()
+        {
+            CanKeyboardFocus = true;
+            KeyboardFocusOnClick = true;
+            MouseFilter = MouseFilterMode.Stop;
+
+            IoCManager.InjectDependencies(this);
+        }
+
+        protected override void EnteredTree()
+        {
+            base.EnteredTree();
+
+            _cef.CheckInitialized();
+
+            DebugTools.AssertNull(_data);
+
+            // A funny render handler that will allow us to render to the control.
+            var renderer = new ControlRenderHandler(this);
+
+            // A funny web cef client. This can actually be shared by multiple browsers, but I'm not sure how the
+            // rendering would work in that case? TODO CEF: Investigate a way to share the web client?
+            var client = new RobustCefClient(renderer, _requestHandler, new RobustLoadHandler());
+
+            var info = CefWindowInfo.Create();
+
+            // FUNFACT: If you DO NOT set these below and set info.Width/info.Height instead, you get an external window
+            // Good to know, huh? Setup is the same, except you can pass a dummy render handler to the CEF client.
+            info.SetAsWindowless(IntPtr.Zero, false); // TODO CEF: Pass parent handle?
+            info.WindowlessRenderingEnabled = true;
+
+            var settings = new CefBrowserSettings()
+            {
+                WindowlessFrameRate = 60
+            };
+
+            // Create the web browser! And by default, we go to about:blank.
+            var browser = CefBrowserHost.CreateBrowserSync(info, client, settings, _startUrl);
+
+            var texture = _clyde.CreateBlankTexture<Bgra32>(Vector2i.One);
+
+            _data = new LiveData(texture, client, browser, renderer);
+        }
+
+        protected override void ExitedTree()
+        {
+            base.ExitedTree();
+
+            DebugTools.AssertNotNull(_data);
+
+            _data!.Texture.Dispose();
+            _data.Browser.GetHost().CloseBrowser(true);
+            _data = null;
+        }
+
+        protected internal override void MouseMove(GUIMouseMoveEventArgs args)
+        {
+            base.MouseMove(args);
+
+            if (_data == null)
+                return;
+
+            // Logger.Debug();
+            var modifiers = CalcMouseModifiers();
+            var mouseEvent = new CefMouseEvent(
+                (int) args.RelativePosition.X, (int) args.RelativePosition.Y,
+                modifiers);
+
+            _data.Browser.GetHost().SendMouseMoveEvent(mouseEvent, false);
+        }
+
+        protected internal override void MouseExited()
+        {
+            base.MouseExited();
+
+            if (_data == null)
+                return;
+
+            var modifiers = CalcMouseModifiers();
+
+            _data.Browser.GetHost().SendMouseMoveEvent(new CefMouseEvent(0, 0, modifiers), true);
+        }
+
+        protected internal override void MouseWheel(GUIMouseWheelEventArgs args)
+        {
+            base.MouseWheel(args);
+
+            if (_data == null)
+                return;
+
+            var modifiers = CalcMouseModifiers();
+            var mouseEvent = new CefMouseEvent(
+                (int) args.RelativePosition.X, (int) args.RelativePosition.Y,
+                modifiers);
+
+            _data.Browser.GetHost().SendMouseWheelEvent(
+                mouseEvent,
+                (int) args.Delta.X * ScrollSpeed,
+                (int) args.Delta.Y * ScrollSpeed);
+        }
+
+        bool IRawInputControl.RawKeyEvent(in GuiRawKeyEvent guiRawEvent)
+        {
+            if (_data == null)
+                return false;
+
+            var host = _data.Browser.GetHost();
+
+            if (guiRawEvent.Key is Key.MouseLeft or Key.MouseMiddle or Key.MouseRight)
+            {
+                var key = guiRawEvent.Key switch
+                {
+                    Key.MouseLeft => CefMouseButtonType.Left,
+                    Key.MouseMiddle => CefMouseButtonType.Middle,
+                    Key.MouseRight => CefMouseButtonType.Right,
+                    _ => default // not possible
+                };
+
+                var mouseEvent = new CefMouseEvent(
+                    guiRawEvent.MouseRelative.X, guiRawEvent.MouseRelative.Y,
+                    CefEventFlags.None);
+
+                // Logger.Debug($"MOUSE: {guiRawEvent.Action} {guiRawEvent.Key} {guiRawEvent.ScanCode} {key}");
+
+                // TODO: double click support?
+                host.SendMouseClickEvent(mouseEvent, key, guiRawEvent.Action == RawKeyAction.Up, 1);
+            }
+            else
+            {
+                // TODO: Handle left/right modifier keys??
+                if (!_keyMap.TryGetValue(guiRawEvent.Key, out var vkKey))
+                    vkKey = default;
+
+                // Logger.Debug($"{guiRawEvent.Action} {guiRawEvent.Key} {guiRawEvent.ScanCode} {vkKey}");
+
+                var lParam = 0;
+                lParam |= (guiRawEvent.ScanCode & 0xFF) << 16;
+                if (guiRawEvent.Action != RawKeyAction.Down)
+                    lParam |= 1 << 30;
+
+                if (guiRawEvent.Action == RawKeyAction.Up)
+                    lParam |= 1 << 31;
+
+                var modifiers = CalcModifiers(guiRawEvent.Key);
+
+                host.SendKeyEvent(new CefKeyEvent
+                {
+                    // Repeats are sent as key downs, I guess?
+                    EventType = guiRawEvent.Action == RawKeyAction.Up
+                        ? CefKeyEventType.KeyUp
+                        : CefKeyEventType.RawKeyDown,
+                    NativeKeyCode = lParam,
+                    // NativeKeyCode = guiRawEvent.ScanCode,
+                    WindowsKeyCode = (int) vkKey,
+                    IsSystemKey = false, // TODO
+                    Modifiers = modifiers
+                });
+
+                if (guiRawEvent.Action != RawKeyAction.Up && guiRawEvent.Key == Key.Return)
+                {
+                    host.SendKeyEvent(new CefKeyEvent
+                    {
+                        EventType = CefKeyEventType.Char,
+                        WindowsKeyCode = '\r',
+                        NativeKeyCode = lParam,
+                        Modifiers = modifiers
+                    });
+                }
+            }
+
+            return true;
+        }
+
+        private CefEventFlags CalcModifiers(Key key)
+        {
+            CefEventFlags modifiers = default;
+
+            if (_inputMgr.IsKeyDown(Key.Control))
+                modifiers |= CefEventFlags.ControlDown;
+
+            if (_inputMgr.IsKeyDown(Key.Alt))
+                modifiers |= CefEventFlags.AltDown;
+
+            if (_inputMgr.IsKeyDown(Key.Shift))
+                modifiers |= CefEventFlags.ShiftDown;
+
+            if (_inputMgr.IsKeyDown(Key.Shift))
+                modifiers |= CefEventFlags.ShiftDown;
+
+            return modifiers;
+        }
+
+        private CefEventFlags CalcMouseModifiers()
+        {
+            CefEventFlags modifiers = default;
+
+            if (_inputMgr.IsKeyDown(Key.Control))
+                modifiers |= CefEventFlags.ControlDown;
+
+            if (_inputMgr.IsKeyDown(Key.Alt))
+                modifiers |= CefEventFlags.AltDown;
+
+            if (_inputMgr.IsKeyDown(Key.Shift))
+                modifiers |= CefEventFlags.ShiftDown;
+
+            if (_inputMgr.IsKeyDown(Key.Shift))
+                modifiers |= CefEventFlags.ShiftDown;
+
+            if (_inputMgr.IsKeyDown(Key.MouseLeft))
+                modifiers |= CefEventFlags.LeftMouseButton;
+
+            if (_inputMgr.IsKeyDown(Key.MouseMiddle))
+                modifiers |= CefEventFlags.MiddleMouseButton;
+
+            if (_inputMgr.IsKeyDown(Key.MouseRight))
+                modifiers |= CefEventFlags.RightMouseButton;
+
+            return modifiers;
+        }
+
+        protected internal override void TextEntered(GUITextEventArgs args)
+        {
+            base.TextEntered(args);
+
+            if (_data == null)
+                return;
+
+            var host = _data.Browser.GetHost();
+
+            Span<char> buf = stackalloc char[2];
+            var written = args.AsRune.EncodeToUtf16(buf);
+
+            for (var i = 0; i < written; i++)
+            {
+                host.SendKeyEvent(new CefKeyEvent
+                {
+                    EventType = CefKeyEventType.Char,
+                    WindowsKeyCode = buf[i],
+                    Character = buf[i],
+                    UnmodifiedCharacter = buf[i]
+                });
+            }
+        }
+
+        protected override void Resized()
+        {
+            base.Resized();
+
+            if (_data == null)
+                return;
+
+            _data.Browser.GetHost().NotifyMoveOrResizeStarted();
+            _data.Browser.GetHost().WasResized();
+            _data.Texture.Dispose();
+            _data.Texture = _clyde.CreateBlankTexture<Bgra32>((PixelWidth, PixelHeight));
+        }
+
+        protected internal override void Draw(DrawingHandleScreen handle)
+        {
+            base.Draw(handle);
+
+            if (_data == null)
+                return;
+
+            var bufImg = _data.Renderer.Buffer.Buffer;
+
+            _data.Texture.SetSubImage(
+                Vector2i.Zero,
+                bufImg,
+                new UIBox2i(
+                    0, 0,
+                    Math.Min(PixelWidth, bufImg.Width),
+                    Math.Min(PixelHeight, bufImg.Height)));
+
+            handle.DrawTexture(_data.Texture, Vector2.Zero);
+        }
+
+        public void StopLoad()
+        {
+            if (_data == null)
+                throw new InvalidOperationException();
+
+            _data.Browser.StopLoad();
+        }
+
+        public void Reload()
+        {
+            if (_data == null)
+                throw new InvalidOperationException();
+
+            _data.Browser.Reload();
+        }
+
+        public bool GoBack()
+        {
+            if (_data == null)
+                throw new InvalidOperationException();
+
+            if (!_data.Browser.CanGoBack)
+                return false;
+
+            _data.Browser.GoBack();
+            return true;
+        }
+
+        public bool GoForward()
+        {
+            if (_data == null)
+                throw new InvalidOperationException();
+
+            if (!_data.Browser.CanGoForward)
+                return false;
+
+            _data.Browser.GoForward();
+            return true;
+        }
+
+        public void ExecuteJavaScript(string code)
+        {
+            if (_data == null)
+                throw new InvalidOperationException();
+
+            // TODO: this should not run until the browser is done loading seriously does this even work?
+            _data.Browser.GetMainFrame().ExecuteJavaScript(code, string.Empty, 1);
+        }
+
+        public void AddResourceRequestHandler(Action<RequestHandlerContext> handler)
+        {
+            _requestHandler.AddResourceRequestHandler(handler);
+        }
+
+        public void RemoveResourceRequestHandler(Action<RequestHandlerContext> handler)
+        {
+            _requestHandler.RemoveResourceRequestHandler(handler);
+        }
+
+        public void AddBeforeBrowseHandler(Action<BeforeBrowseContext> handler)
+        {
+            _requestHandler.AddBeforeBrowseHandler(handler);
+        }
+
+        public void RemoveBeforeBrowseHandler(Action<BeforeBrowseContext> handler)
+        {
+            _requestHandler.RemoveBeforeBrowseHandler(handler);
+        }
+
+        private sealed class LiveData
+        {
+            public OwnedTexture Texture;
+            public readonly RobustCefClient Client;
+            public readonly CefBrowser Browser;
+            public readonly ControlRenderHandler Renderer;
+
+            public LiveData(
+                OwnedTexture texture,
+                RobustCefClient client,
+                CefBrowser browser,
+                ControlRenderHandler renderer)
+            {
+                Texture = texture;
+                Client = client;
+                Browser = browser;
+                Renderer = renderer;
+            }
+        }
+    }
+
+    internal class ControlRenderHandler : CefRenderHandler
+    {
+        public ImageBuffer Buffer { get; }
+        private Control _control;
+
+        internal ControlRenderHandler(Control control)
+        {
+            Buffer = new ImageBuffer(control);
+            _control = control;
+        }
+
+        protected override CefAccessibilityHandler? GetAccessibilityHandler() => null;
+
+        protected override void GetViewRect(CefBrowser browser, out CefRectangle rect)
+        {
+            if (_control.Disposed)
+            {
+                rect = new CefRectangle();
+                return;
+            }
+
+            // TODO CEF: Do we need to pass real screen coords? Cause what we do already works...
+            //var screenCoords = _control.ScreenCoordinates;
+            //rect = new CefRectangle((int) screenCoords.X, (int) screenCoords.Y, (int)Math.Max(_control.Size.X, 1), (int)Math.Max(_control.Size.Y, 1));
+
+            // We do the max between size and 1 because it will LITERALLY CRASH WITHOUT AN ERROR otherwise.
+            rect = new CefRectangle(0, 0, (int) Math.Max(_control.Size.X, 1), (int) Math.Max(_control.Size.Y, 1));
+        }
+
+        protected override bool GetScreenInfo(CefBrowser browser, CefScreenInfo screenInfo)
+        {
+            if (_control.Disposed)
+                return false;
+
+            // TODO CEF: Get actual scale factor?
+            screenInfo.DeviceScaleFactor = 1.0f;
+
+            return true;
+        }
+
+        protected override void OnPopupSize(CefBrowser browser, CefRectangle rect)
+        {
+            if (_control.Disposed)
+                return;
+        }
+
+        protected override void OnPaint(CefBrowser browser, CefPaintElementType type, CefRectangle[] dirtyRects,
+            IntPtr buffer, int width, int height)
+        {
+            if (_control.Disposed)
+                return;
+
+            foreach (var dirtyRect in dirtyRects)
+            {
+                Buffer.UpdateBuffer(width, height, buffer, dirtyRect);
+            }
+        }
+
+        protected override void OnAcceleratedPaint(CefBrowser browser, CefPaintElementType type,
+            CefRectangle[] dirtyRects, IntPtr sharedHandle)
+        {
+            // Unused, but we're forced to implement it so.. NOOP.
+        }
+
+        protected override void OnScrollOffsetChanged(CefBrowser browser, double x, double y)
+        {
+            if (_control.Disposed)
+                return;
+        }
+
+        protected override void OnImeCompositionRangeChanged(CefBrowser browser, CefRange selectedRange,
+            CefRectangle[] characterBounds)
+        {
+            if (_control.Disposed)
+                return;
+        }
+    }
+}

Robust.Client.CEF/BrowserWindowCreateParameters.cs

@@ -0,0 +1,16 @@
+namespace Robust.Client.CEF
+{
+    public sealed class BrowserWindowCreateParameters
+    {
+        public int Width { get; set; }
+        public int Height { get; set; }
+
+        public string Url { get; set; } = "about:blank";
+
+        public BrowserWindowCreateParameters(int width, int height)
+        {
+            Width = width;
+            Height = height;
+        }
+    }
+}

Robust.Client.CEF/CefKeyCodes.cs

@@ -0,0 +1,225 @@
+
+using System.Diagnostics.CodeAnalysis;
+
+namespace Robust.Client.CEF
+{
+    [SuppressMessage("ReSharper", "InconsistentNaming")]
+    [SuppressMessage("ReSharper", "UnusedMember.Global")]
+    [SuppressMessage("ReSharper", "IdentifierTypo")]
+    [SuppressMessage("ReSharper", "CA1069")]
+    [SuppressMessage("ReSharper", "CommentTypo")]
+    internal static class CefKeyCodes
+    {
+        // Taken from https://chromium.googlesource.com/chromium/src/+/refs/heads/main/ui/events/keycodes/keyboard_codes_posix.h
+        // See also https://docs.microsoft.com/en-us/windows/win32/inputdev/virtual-key-codes
+        public enum ChromiumKeyboardCode
+        {
+            VKEY_CANCEL = 0x03,
+            VKEY_BACK = 0x08,
+            VKEY_TAB = 0x09,
+            VKEY_BACKTAB = 0x0A,
+            VKEY_CLEAR = 0x0C,
+            VKEY_RETURN = 0x0D,
+            VKEY_SHIFT = 0x10,
+            VKEY_CONTROL = 0x11,
+            VKEY_MENU = 0x12,
+            VKEY_PAUSE = 0x13,
+            VKEY_CAPITAL = 0x14,
+            VKEY_KANA = 0x15,
+            VKEY_HANGUL = 0x15,
+            VKEY_PASTE = 0x16,
+            VKEY_JUNJA = 0x17,
+            VKEY_FINAL = 0x18,
+            VKEY_HANJA = 0x19,
+            VKEY_KANJI = 0x19,
+            VKEY_ESCAPE = 0x1B,
+            VKEY_CONVERT = 0x1C,
+            VKEY_NONCONVERT = 0x1D,
+            VKEY_ACCEPT = 0x1E,
+            VKEY_MODECHANGE = 0x1F,
+            VKEY_SPACE = 0x20,
+            VKEY_PRIOR = 0x21,
+            VKEY_NEXT = 0x22,
+            VKEY_END = 0x23,
+            VKEY_HOME = 0x24,
+            VKEY_LEFT = 0x25,
+            VKEY_UP = 0x26,
+            VKEY_RIGHT = 0x27,
+            VKEY_DOWN = 0x28,
+            VKEY_SELECT = 0x29,
+            VKEY_PRINT = 0x2A,
+            VKEY_EXECUTE = 0x2B,
+            VKEY_SNAPSHOT = 0x2C, // Print Screen / SysRq
+            VKEY_INSERT = 0x2D,
+            VKEY_DELETE = 0x2E,
+            VKEY_HELP = 0x2F,
+            VKEY_0 = 0x30,
+            VKEY_1 = 0x31,
+            VKEY_2 = 0x32,
+            VKEY_3 = 0x33,
+            VKEY_4 = 0x34,
+            VKEY_5 = 0x35,
+            VKEY_6 = 0x36,
+            VKEY_7 = 0x37,
+            VKEY_8 = 0x38,
+            VKEY_9 = 0x39,
+            VKEY_A = 0x41,
+            VKEY_B = 0x42,
+            VKEY_C = 0x43,
+            VKEY_D = 0x44,
+            VKEY_E = 0x45,
+            VKEY_F = 0x46,
+            VKEY_G = 0x47,
+            VKEY_H = 0x48,
+            VKEY_I = 0x49,
+            VKEY_J = 0x4A,
+            VKEY_K = 0x4B,
+            VKEY_L = 0x4C,
+            VKEY_M = 0x4D,
+            VKEY_N = 0x4E,
+            VKEY_O = 0x4F,
+            VKEY_P = 0x50,
+            VKEY_Q = 0x51,
+            VKEY_R = 0x52,
+            VKEY_S = 0x53,
+            VKEY_T = 0x54,
+            VKEY_U = 0x55,
+            VKEY_V = 0x56,
+            VKEY_W = 0x57,
+            VKEY_X = 0x58,
+            VKEY_Y = 0x59,
+            VKEY_Z = 0x5A,
+            VKEY_LWIN = 0x5B,
+            VKEY_COMMAND = VKEY_LWIN, // Provide the Mac name for convenience.
+            VKEY_RWIN = 0x5C,
+            VKEY_APPS = 0x5D,
+            VKEY_SLEEP = 0x5F,
+            VKEY_NUMPAD0 = 0x60,
+            VKEY_NUMPAD1 = 0x61,
+            VKEY_NUMPAD2 = 0x62,
+            VKEY_NUMPAD3 = 0x63,
+            VKEY_NUMPAD4 = 0x64,
+            VKEY_NUMPAD5 = 0x65,
+            VKEY_NUMPAD6 = 0x66,
+            VKEY_NUMPAD7 = 0x67,
+            VKEY_NUMPAD8 = 0x68,
+            VKEY_NUMPAD9 = 0x69,
+            VKEY_MULTIPLY = 0x6A,
+            VKEY_ADD = 0x6B,
+            VKEY_SEPARATOR = 0x6C,
+            VKEY_SUBTRACT = 0x6D,
+            VKEY_DECIMAL = 0x6E,
+            VKEY_DIVIDE = 0x6F,
+            VKEY_F1 = 0x70,
+            VKEY_F2 = 0x71,
+            VKEY_F3 = 0x72,
+            VKEY_F4 = 0x73,
+            VKEY_F5 = 0x74,
+            VKEY_F6 = 0x75,
+            VKEY_F7 = 0x76,
+            VKEY_F8 = 0x77,
+            VKEY_F9 = 0x78,
+            VKEY_F10 = 0x79,
+            VKEY_F11 = 0x7A,
+            VKEY_F12 = 0x7B,
+            VKEY_F13 = 0x7C,
+            VKEY_F14 = 0x7D,
+            VKEY_F15 = 0x7E,
+            VKEY_F16 = 0x7F,
+            VKEY_F17 = 0x80,
+            VKEY_F18 = 0x81,
+            VKEY_F19 = 0x82,
+            VKEY_F20 = 0x83,
+            VKEY_F21 = 0x84,
+            VKEY_F22 = 0x85,
+            VKEY_F23 = 0x86,
+            VKEY_F24 = 0x87,
+            VKEY_NUMLOCK = 0x90,
+            VKEY_SCROLL = 0x91,
+            VKEY_LSHIFT = 0xA0,
+            VKEY_RSHIFT = 0xA1,
+            VKEY_LCONTROL = 0xA2,
+            VKEY_RCONTROL = 0xA3,
+            VKEY_LMENU = 0xA4,
+            VKEY_RMENU = 0xA5,
+            VKEY_BROWSER_BACK = 0xA6,
+            VKEY_BROWSER_FORWARD = 0xA7,
+            VKEY_BROWSER_REFRESH = 0xA8,
+            VKEY_BROWSER_STOP = 0xA9,
+            VKEY_BROWSER_SEARCH = 0xAA,
+            VKEY_BROWSER_FAVORITES = 0xAB,
+            VKEY_BROWSER_HOME = 0xAC,
+            VKEY_VOLUME_MUTE = 0xAD,
+            VKEY_VOLUME_DOWN = 0xAE,
+            VKEY_VOLUME_UP = 0xAF,
+            VKEY_MEDIA_NEXT_TRACK = 0xB0,
+            VKEY_MEDIA_PREV_TRACK = 0xB1,
+            VKEY_MEDIA_STOP = 0xB2,
+            VKEY_MEDIA_PLAY_PAUSE = 0xB3,
+            VKEY_MEDIA_LAUNCH_MAIL = 0xB4,
+            VKEY_MEDIA_LAUNCH_MEDIA_SELECT = 0xB5,
+            VKEY_MEDIA_LAUNCH_APP1 = 0xB6,
+            VKEY_MEDIA_LAUNCH_APP2 = 0xB7,
+            VKEY_OEM_1 = 0xBA,
+            VKEY_OEM_PLUS = 0xBB,
+            VKEY_OEM_COMMA = 0xBC,
+            VKEY_OEM_MINUS = 0xBD,
+            VKEY_OEM_PERIOD = 0xBE,
+            VKEY_OEM_2 = 0xBF,
+            VKEY_OEM_3 = 0xC0,
+            VKEY_OEM_4 = 0xDB,
+            VKEY_OEM_5 = 0xDC,
+            VKEY_OEM_6 = 0xDD,
+            VKEY_OEM_7 = 0xDE,
+            VKEY_OEM_8 = 0xDF,
+            VKEY_OEM_102 = 0xE2,
+            VKEY_OEM_103 = 0xE3, // GTV KEYCODE_MEDIA_REWIND
+            VKEY_OEM_104 = 0xE4, // GTV KEYCODE_MEDIA_FAST_FORWARD
+            VKEY_PROCESSKEY = 0xE5,
+            VKEY_PACKET = 0xE7,
+            VKEY_OEM_ATTN = 0xF0, // JIS DomKey::ALPHANUMERIC
+            VKEY_OEM_FINISH = 0xF1, // JIS DomKey::KATAKANA
+            VKEY_OEM_COPY = 0xF2, // JIS DomKey::HIRAGANA
+            VKEY_DBE_SBCSCHAR = 0xF3, // JIS DomKey::HANKAKU
+            VKEY_DBE_DBCSCHAR = 0xF4, // JIS DomKey::ZENKAKU
+            VKEY_OEM_BACKTAB = 0xF5, // JIS DomKey::ROMAJI
+            VKEY_ATTN = 0xF6, // DomKey::ATTN or JIS DomKey::KANA_MODE
+            VKEY_CRSEL = 0xF7,
+            VKEY_EXSEL = 0xF8,
+            VKEY_EREOF = 0xF9,
+            VKEY_PLAY = 0xFA,
+            VKEY_ZOOM = 0xFB,
+            VKEY_NONAME = 0xFC,
+            VKEY_PA1 = 0xFD,
+            VKEY_OEM_CLEAR = 0xFE,
+            VKEY_UNKNOWN = 0,
+
+            // POSIX specific VKEYs. Note that as of Windows SDK 7.1, 0x97-9F, 0xD8-DA,
+            // and 0xE8 are unassigned.
+            VKEY_WLAN = 0x97,
+            VKEY_POWER = 0x98,
+            VKEY_ASSISTANT = 0x99,
+            VKEY_SETTINGS = 0x9A,
+            VKEY_PRIVACY_SCREEN_TOGGLE = 0x9B,
+            VKEY_BRIGHTNESS_DOWN = 0xD8,
+            VKEY_BRIGHTNESS_UP = 0xD9,
+            VKEY_KBD_BRIGHTNESS_DOWN = 0xDA,
+            VKEY_KBD_BRIGHTNESS_UP = 0xE8,
+
+            // Windows does not have a specific key code for AltGr. We use the unused 0xE1
+            // (VK_OEM_AX) code to represent AltGr, matching the behaviour of Firefox on
+            // Linux.
+            VKEY_ALTGR = 0xE1,
+
+            // Windows does not have a specific key code for Compose. We use the unused
+            // 0xE6 (VK_ICO_CLEAR) code to represent Compose.
+            VKEY_COMPOSE = 0xE6,
+
+            // Windows does not have specific key codes for Media Play and Media Pause. We
+            // use the unused 0xE9 (VK_OEM_RESET) and 0xEA (VK_OEM_JUMP) codes to
+            // represent them.
+            VKEY_MEDIA_PLAY = 0xE9,
+            VKEY_MEDIA_PAUSE = 0xEA,
+        };
+    }
+}

Robust.Client.CEF/CefManager.BrowserWindow.cs

@@ -0,0 +1,186 @@
+using System;
+using System.Collections.Generic;
+using Robust.Client.Graphics;
+using Robust.Shared.IoC;
+using Robust.Shared.Log;
+using Robust.Shared.ViewVariables;
+using Xilium.CefGlue;
+
+namespace Robust.Client.CEF
+{
+    public partial class CefManager
+    {
+        [Dependency] private readonly IClydeInternal _clyde = default!;
+
+        private readonly List<BrowserWindowImpl> _browserWindows = new();
+
+        public IEnumerable<IBrowserWindow> AllBrowserWindows => _browserWindows;
+
+        public IBrowserWindow CreateBrowserWindow(BrowserWindowCreateParameters createParams)
+        {
+            var mainHWnd = (_clyde.MainWindow as IClydeWindowInternal)?.WindowsHWnd ?? 0;
+
+            var info = CefWindowInfo.Create();
+            info.Width = createParams.Width;
+            info.Height = createParams.Height;
+            info.SetAsPopup(mainHWnd, "ss14cef");
+
+            var impl = new BrowserWindowImpl(this);
+
+            var lifeSpanHandler = new WindowLifeSpanHandler(impl);
+            var reqHandler = new RobustRequestHandler(Logger.GetSawmill("root"));
+            var client = new WindowCefClient(lifeSpanHandler, reqHandler);
+            var settings = new CefBrowserSettings();
+
+            impl.Browser = CefBrowserHost.CreateBrowserSync(info, client, settings, createParams.Url);
+            impl.RequestHandler = reqHandler;
+
+            _browserWindows.Add(impl);
+
+            return impl;
+        }
+
+        private sealed class BrowserWindowImpl : IBrowserWindow
+        {
+            private readonly CefManager _manager;
+            internal CefBrowser Browser = default!;
+            internal RobustRequestHandler RequestHandler = default!;
+
+            public Action<RequestHandlerContext>? OnResourceRequest { get; set; }
+
+            [ViewVariables(VVAccess.ReadWrite)]
+            public string Url
+            {
+                get
+                {
+                    CheckClosed();
+                    return Browser.GetMainFrame().Url;
+                }
+                set
+                {
+                    CheckClosed();
+                    Browser.GetMainFrame().LoadUrl(value);
+                }
+            }
+
+            [ViewVariables]
+            public bool IsLoading
+            {
+                get
+                {
+                    CheckClosed();
+                    return Browser.IsLoading;
+                }
+            }
+
+            public BrowserWindowImpl(CefManager manager)
+            {
+                _manager = manager;
+            }
+
+            public void StopLoad()
+            {
+                CheckClosed();
+                Browser.StopLoad();
+            }
+
+            public void Reload()
+            {
+                CheckClosed();
+                Browser.Reload();
+            }
+
+            public bool GoBack()
+            {
+                CheckClosed();
+                if (!Browser.CanGoBack)
+                    return false;
+
+                Browser.GoBack();
+                return true;
+            }
+
+            public bool GoForward()
+            {
+                CheckClosed();
+                if (!Browser.CanGoForward)
+                    return false;
+
+                Browser.GoForward();
+                return true;
+            }
+
+            public void ExecuteJavaScript(string code)
+            {
+                CheckClosed();
+                Browser.GetMainFrame().ExecuteJavaScript(code, string.Empty, 1);
+            }
+
+            public void AddResourceRequestHandler(Action<RequestHandlerContext> handler)
+            {
+                RequestHandler.AddResourceRequestHandler(handler);
+            }
+
+            public void RemoveResourceRequestHandler(Action<RequestHandlerContext> handler)
+            {
+                RequestHandler.RemoveResourceRequestHandler(handler);
+            }
+
+            public void Dispose()
+            {
+                if (Closed)
+                    return;
+
+                Browser.GetHost().CloseBrowser(true);
+                Closed = true;
+            }
+
+            public bool Closed { get; private set; }
+
+            public void OnClose()
+            {
+                Closed = true;
+                _manager._browserWindows.Remove(this);
+                Logger.Debug("Removing window");
+            }
+
+            private void CheckClosed()
+            {
+                if (Closed)
+                    throw new ObjectDisposedException("BrowserWindow");
+            }
+        }
+
+        private sealed class WindowCefClient : CefClient
+        {
+            private readonly CefLifeSpanHandler _lifeSpanHandler;
+            private readonly CefRequestHandler _requestHandler;
+
+            public WindowCefClient(CefLifeSpanHandler lifeSpanHandler, CefRequestHandler requestHandler)
+            {
+                _lifeSpanHandler = lifeSpanHandler;
+                _requestHandler = requestHandler;
+            }
+
+            protected override CefLifeSpanHandler GetLifeSpanHandler() => _lifeSpanHandler;
+            protected override CefRequestHandler GetRequestHandler() => _requestHandler;
+        }
+
+        private sealed class WindowLifeSpanHandler : CefLifeSpanHandler
+        {
+            private readonly BrowserWindowImpl _windowImpl;
+
+            public WindowLifeSpanHandler(BrowserWindowImpl windowImpl)
+            {
+                _windowImpl = windowImpl;
+            }
+
+            protected override void OnBeforeClose(CefBrowser browser)
+            {
+                base.OnBeforeClose(browser);
+
+                _windowImpl.OnClose();
+            }
+        }
+    }
+}

Robust.Client.CEF/CefManager.cs

@@ -0,0 +1,104 @@
+using System;
+using System.IO;
+using JetBrains.Annotations;
+using Robust.Shared.ContentPack;
+using Robust.Shared.Log;
+using Robust.Shared.Utility;
+
+// The library we're using right now. TODO CEF: Do we want to use something else? We will need to ship it ourselves if so.
+using Xilium.CefGlue;
+
+namespace Robust.Client.CEF
+{
+    // Register this with IoC.
+    // TODO CEF: think if making this inherit CefApp is a good idea...
+    // TODO CEF: A way to handle external window browsers...
+    [UsedImplicitly]
+    public partial class CefManager
+    {
+        private CefApp _app = default!;
+        private bool _initialized = false;
+
+        /// <summary>
+        ///     Call this to initialize CEF.
+        /// </summary>
+        public void Initialize()
+        {
+            DebugTools.Assert(!_initialized);
+
+            string subProcessName;
+            if (OperatingSystem.IsWindows())
+                subProcessName = "Robust.Client.CEF.exe";
+            else if (OperatingSystem.IsLinux())
+                subProcessName = "Robust.Client.CEF";
+            else
+                throw new NotSupportedException("Unsupported platform for CEF!");
+
+            var subProcessPath = PathHelpers.ExecutableRelativeFile(subProcessName);
+
+            var settings = new CefSettings()
+            {
+                WindowlessRenderingEnabled = true, // So we can render to our UI controls.
+                ExternalMessagePump = false, // Unsure, honestly. TODO CEF: Research this?
+                NoSandbox = true, // Not disabling the sandbox crashes CEF.
+                BrowserSubprocessPath = subProcessPath,
+                LocalesDirPath = Path.Combine(PathHelpers.GetExecutableDirectory(), "locales"),
+                ResourcesDirPath = PathHelpers.GetExecutableDirectory(),
+                RemoteDebuggingPort = 9222
+            };
+
+            Logger.Info($"CEF Version: {CefRuntime.ChromeVersion}");
+
+            // --------------------------- README --------------------------------------------------
+            // By the way! You're gonna need the CEF binaries in your client's bin folder.
+            // More specifically, version cef_binary_91.1.21+g9dd45fe+chromium-91.0.4472.114
+            // https://cef-builds.spotifycdn.com/cef_binary_91.1.21%2Bg9dd45fe%2Bchromium-91.0.4472.114_windows64_minimal.tar.bz2
+            // https://cef-builds.spotifycdn.com/cef_binary_91.1.21%2Bg9dd45fe%2Bchromium-91.0.4472.114_linux64_minimal.tar.bz2
+            // Here's how to get it to work:
+            // 1. Copy all the contents of "Release" to the bin folder.
+            // 2. Copy all the contents of "Resources" to the bin folder.
+            // Supposedly, you should just need libcef.so in Release and icudtl.dat in Resources...
+            // The rest might be optional.
+            // Maybe. Good luck! If you get odd crashes with no info and a weird exit code, use GDB!
+            // -------------------------------------------------------------------------------------
+
+            _app = new RobustCefApp();
+
+            // We pass no main arguments...
+            CefRuntime.Initialize(new CefMainArgs(null), settings, _app, IntPtr.Zero);
+
+            // TODO CEF: After this point, debugging breaks. No, literally. My client crashes but ONLY with the debugger.
+            // I have tried using the DEBUG and RELEASE versions of libcef.so, stripped or non-stripped...
+            // And nothing seemed to work. Odd.
+
+            _initialized = true;
+        }
+
+        public void CheckInitialized()
+        {
+            if (!_initialized)
+                throw new InvalidOperationException("CefManager has not been initialized!");
+        }
+
+        /// <summary>
+        ///     Needs to be called regularly for CEF to keep working.
+        /// </summary>
+        public void Update()
+        {
+            DebugTools.Assert(_initialized);
+
+            // Calling this makes CEF do its work, without using its own update loop.
+            CefRuntime.DoMessageLoopWork();
+        }
+
+        /// <summary>
+        ///     Call before program shutdown.
+        /// </summary>
+        public void Shutdown()
+        {
+            DebugTools.Assert(_initialized);
+
+            CefRuntime.Shutdown();
+        }
+    }
+}

Robust.Client.CEF/IBrowserControl.cs

@@ -0,0 +1,48 @@
+using System;
+
+namespace Robust.Client.CEF
+{
+    public interface IBrowserControl
+    {
+        /// <summary>
+        ///     Current URL of the browser. Set to load a new page.
+        /// </summary>
+        string Url { get; set; }
+
+        /// <summary>
+        ///     Whether the browser is currently loading a page.
+        /// </summary>
+        bool IsLoading { get; }
+
+        /// <summary>
+        ///     Stops loading the current page.
+        /// </summary>
+        void StopLoad();
+
+        /// <summary>
+        ///     Reload the current page.
+        /// </summary>
+        void Reload();
+
+        /// <summary>
+        ///     Navigate back.
+        /// </summary>
+        /// <returns>Whether the browser could navigate back.</returns>
+        bool GoBack();
+
+        /// <summary>
+        ///     Navigate forward.
+        /// </summary>
+        /// <returns>Whether the browser could navigate forward.</returns>
+        bool GoForward();
+
+        /// <summary>
+        ///     Execute arbitrary JavaScript on the current page.
+        /// </summary>
+        /// <param name="code">JavaScript code.</param>
+        void ExecuteJavaScript(string code);
+
+        void AddResourceRequestHandler(Action<RequestHandlerContext> handler);
+        void RemoveResourceRequestHandler(Action<RequestHandlerContext> handler);
+    }
+}

Robust.Client.CEF/IBrowserWindow.cs

@@ -0,0 +1,9 @@
+using System;
+
+namespace Robust.Client.CEF
+{
+    public interface IBrowserWindow : IBrowserControl, IDisposable
+    {
+        bool Closed { get; }
+    }
+}

Robust.Client.CEF/ImageBuffer.cs

@@ -0,0 +1,42 @@
+using System;
+using Robust.Client.UserInterface;
+using Robust.Client.Utility;
+using Robust.Shared.Maths;
+using SixLabors.ImageSharp;
+using SixLabors.ImageSharp.PixelFormats;
+using Xilium.CefGlue;
+
+namespace Robust.Client.CEF
+{
+    internal sealed class ImageBuffer
+    {
+        private readonly Control _control;
+
+        public ImageBuffer(Control control)
+        {
+            _control = control;
+        }
+
+        public Image<Bgra32> Buffer { get; private set; } = new(1, 1);
+
+        public unsafe void UpdateBuffer(int width, int height, IntPtr buffer, CefRectangle dirtyRect)
+        {
+            if (width != Buffer.Width || height != Buffer.Height)
+                UpdateSize(width, height);
+
+            var span = new ReadOnlySpan<Bgra32>((void*) buffer, width * height);
+
+            ImageSharpExt.Blit(
+                span,
+                width,
+                UIBox2i.FromDimensions(dirtyRect.X, dirtyRect.Y, dirtyRect.Width, dirtyRect.Height),
+                Buffer,
+                (dirtyRect.X, dirtyRect.Y));
+        }
+
+        private void UpdateSize(int width, int height)
+        {
+            Buffer = new Image<Bgra32>(width, height);
+        }
+    }
+}

Robust.Client.CEF/Program.cs

@@ -0,0 +1,33 @@
+using System;
+using Xilium.CefGlue;
+
+namespace Robust.Client.CEF
+{
+    public 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)
+        {
+            // This is a workaround for this to work on UNIX.
+            var argv = args;
+            if (CefRuntime.Platform != CefRuntimePlatform.Windows)
+            {
+                argv = new string[args.Length + 1];
+                Array.Copy(args, 0, argv, 1, args.Length);
+                argv[0] = "-";
+            }
+
+            var mainArgs = new CefMainArgs(argv);
+
+            // This will block executing until the subprocess is shut down.
+            var code = CefRuntime.ExecuteProcess(mainArgs, null, IntPtr.Zero);
+
+            if (code != 0)
+            {
+                System.Console.WriteLine($"CEF Subprocess exited unsuccessfully with exit code {code}! Arguments: {string.Join(' ', argv)}");
+            }
+
+            return code;
+        }
+    }
+}

Robust.Client.CEF/RequestHandlerContext.cs

@@ -0,0 +1,56 @@
+using System;
+using System.IO;
+using System.Net;
+using Xilium.CefGlue;
+
+namespace Robust.Client.CEF
+{
+    public sealed class RequestHandlerContext
+    {
+        internal readonly CefRequest CefRequest;
+
+        public bool IsNavigation { get; }
+        public bool IsDownload { get; }
+        public string RequestInitiator { get; }
+
+        public string Url => CefRequest.Url;
+        public string Method => CefRequest.Method;
+
+        public bool IsHandled { get; private set; }
+
+        public bool IsCancelled { get; private set; }
+
+        internal IRequestResult? Result { get; private set; }
+
+        internal RequestHandlerContext(
+            bool isNavigation,
+            bool isDownload,
+            string requestInitiator,
+            CefRequest cefRequest)
+        {
+            CefRequest = cefRequest;
+            IsNavigation = isNavigation;
+            IsDownload = isDownload;
+            RequestInitiator = requestInitiator;
+        }
+
+        public void DoCancel()
+        {
+            CheckNotHandled();
+
+            IsHandled = true;
+            IsCancelled = true;
+        }
+
+        public void DoRespondStream(Stream stream, string contentType, HttpStatusCode code = HttpStatusCode.OK)
+        {
+            Result = new RequestResultStream(stream, contentType, code);
+        }
+
+        private void CheckNotHandled()
+        {
+            if (IsHandled)
+                throw new InvalidOperationException("Request has already been handled");
+        }
+    }
+}

Robust.Client.CEF/RequestResults.cs

@@ -0,0 +1,93 @@
+using System;
+using System.IO;
+using System.Net;
+using Xilium.CefGlue;
+
+namespace Robust.Client.CEF
+{
+    internal interface IRequestResult
+    {
+        CefResourceHandler MakeHandler();
+    }
+
+    internal sealed class RequestResultStream : IRequestResult
+    {
+        private readonly Stream _stream;
+        private readonly HttpStatusCode _code;
+        private readonly string _contentType;
+
+        public RequestResultStream(Stream stream, string contentType, HttpStatusCode code)
+        {
+            _stream = stream;
+            _code = code;
+            _contentType = contentType;
+        }
+
+        public CefResourceHandler MakeHandler()
+        {
+            return new Handler(_stream, _contentType, _code);
+        }
+
+        private sealed class Handler : CefResourceHandler
+        {
+            // TODO: async
+            // TODO: exception handling
+
+            private readonly Stream _stream;
+            private readonly HttpStatusCode _code;
+            private readonly string _contentType;
+
+            public Handler(Stream stream, string contentType, HttpStatusCode code)
+            {
+                _stream = stream;
+                _code = code;
+                _contentType = contentType;
+            }
+
+            protected override bool Open(CefRequest request, out bool handleRequest, CefCallback callback)
+            {
+                handleRequest = true;
+                return true;
+            }
+
+            protected override void GetResponseHeaders(CefResponse response, out long responseLength, out string? redirectUrl)
+            {
+                response.Status = (int) _code;
+                response.StatusText = _code.ToString();
+                response.MimeType = _contentType;
+
+                if (_stream.CanSeek)
+                    responseLength = _stream.Length;
+                else
+                    responseLength = -1;
+
+                redirectUrl = default;
+            }
+
+            protected override bool Skip(long bytesToSkip, out long bytesSkipped, CefResourceSkipCallback callback)
+            {
+                if (!_stream.CanSeek)
+                {
+                    bytesSkipped = -2;
+                    return false;
+                }
+
+                bytesSkipped = _stream.Seek(bytesToSkip, SeekOrigin.Begin);
+                return true;
+            }
+
+            protected override unsafe bool Read(IntPtr dataOut, int bytesToRead, out int bytesRead, CefResourceReadCallback callback)
+            {
+                var byteSpan = new Span<byte>((void*) dataOut, bytesToRead);
+
+                bytesRead = _stream.Read(byteSpan);
+
+                return bytesRead != 0;
+            }
+
+            protected override void Cancel()
+            {
+            }
+        }
+    }
+}

Robust.Client.CEF/Robust.Client.CEF.csproj

@@ -0,0 +1,25 @@
+<Project Sdk="Microsoft.NET.Sdk">
+    <Import Project="..\MSBuild\Robust.Properties.targets" />
+    <Import Project="..\MSBuild\Robust.Engine.props" />
+    <PropertyGroup>
+        <TargetFramework>net5.0</TargetFramework>
+        <PlatformTarget>x64</PlatformTarget>
+        <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+        <OutputType>WinExe</OutputType>
+    </PropertyGroup>
+
+    <Import Project="..\MSBuild\Robust.DefineConstants.targets" />
+    <Target Name="RobustAfterBuild" AfterTargets="Build" />
+    <Import Project="..\MSBuild\Robust.Engine.targets" />
+
+    <ItemGroup>
+      <PackageReference Include="JetBrains.Annotations" Version="2020.3.0" />
+      <PackageReference Include="System.Drawing.Common" Version="5.0.2" />
+    </ItemGroup>
+
+    <ItemGroup>
+      <ProjectReference Include="..\cefglue\CefGlue\CefGlue.csproj" />
+      <ProjectReference Include="..\Robust.Client\Robust.Client.csproj" />
+    </ItemGroup>
+
+</Project>

Robust.Client.CEF/RobustCefApp.cs

@@ -0,0 +1,48 @@
+using System;
+using Robust.Shared.IoC;
+using Robust.Shared.Log;
+using Xilium.CefGlue;
+
+namespace Robust.Client.CEF
+{
+    internal class RobustCefApp : CefApp
+    {
+        private readonly BrowserProcessHandler _browserProcessHandler = new();
+        private readonly RenderProcessHandler _renderProcessHandler = new();
+
+        protected override CefBrowserProcessHandler GetBrowserProcessHandler()
+        {
+            return _browserProcessHandler;
+        }
+
+        protected override CefRenderProcessHandler GetRenderProcessHandler()
+        {
+            return _renderProcessHandler;
+        }
+
+        protected override void OnBeforeCommandLineProcessing(string processType, CefCommandLine commandLine)
+        {
+            // Disable zygote on Linux.
+            commandLine.AppendSwitch("--no-zygote");
+
+            //commandLine.AppendSwitch("--disable-gpu");
+            //commandLine.AppendSwitch("--disable-gpu-compositing");
+            //commandLine.AppendSwitch("--in-process-gpu");
+
+            commandLine.AppendSwitch("disable-threaded-scrolling", "1");
+            commandLine.AppendSwitch("disable-features", "TouchpadAndWheelScrollLatching,AsyncWheelEvents");
+
+            if(IoCManager.Instance != null)
+                Logger.Debug($"{commandLine}");
+        }
+
+        private class BrowserProcessHandler : CefBrowserProcessHandler
+        {
+        }
+
+        // TODO CEF: Research - Is this even needed?
+        private class RenderProcessHandler : CefRenderProcessHandler
+        {
+        }
+    }
+}

Robust.Client.CEF/RobustCefClient.cs

@@ -0,0 +1,23 @@
+using Xilium.CefGlue;
+
+namespace Robust.Client.CEF
+{
+    // Simple CEF client.
+    internal class RobustCefClient : CefClient
+    {
+        private readonly CefRenderHandler _renderHandler;
+        private readonly CefRequestHandler _requestHandler;
+        private readonly CefLoadHandler _loadHandler;
+
+        internal RobustCefClient(CefRenderHandler handler, CefRequestHandler requestHandler, CefLoadHandler loadHandler)
+        {
+            _renderHandler = handler;
+            _requestHandler = requestHandler;
+            _loadHandler = loadHandler;
+        }
+
+        protected override CefRenderHandler GetRenderHandler() => _renderHandler;
+        protected override CefRequestHandler GetRequestHandler() => _requestHandler;
+        protected override CefLoadHandler GetLoadHandler() => _loadHandler;
+    }
+}

Robust.Client.CEF/RobustLoadHandler.cs

@@ -0,0 +1,17 @@
+using Xilium.CefGlue;
+
+namespace Robust.Client.CEF
+{
+    public sealed class RobustLoadHandler : CefLoadHandler
+    {
+        protected override void OnLoadStart(CefBrowser browser, CefFrame frame, CefTransitionType transitionType)
+        {
+            base.OnLoadStart(browser, frame, transitionType);
+        }
+
+        protected override void OnLoadEnd(CefBrowser browser, CefFrame frame, int httpStatusCode)
+        {
+            base.OnLoadEnd(browser, frame, httpStatusCode);
+        }
+    }
+}

Robust.Client.CEF/RobustRequestHandler.cs

@@ -0,0 +1,128 @@
+using System;
+using System.Collections.Generic;
+using Robust.Shared.Log;
+using Xilium.CefGlue;
+
+namespace Robust.Client.CEF
+{
+    internal sealed class RobustRequestHandler : CefRequestHandler
+    {
+        private readonly ISawmill _sawmill;
+        private readonly List<Action<RequestHandlerContext>> _resourceRequestHandlers = new();
+        private readonly List<Action<BeforeBrowseContext>> _beforeBrowseHandlers = new();
+
+        public RobustRequestHandler(ISawmill sawmill)
+        {
+            _sawmill = sawmill;
+        }
+
+        public void AddResourceRequestHandler(Action<RequestHandlerContext> handler)
+        {
+            lock (_resourceRequestHandlers)
+            {
+                _resourceRequestHandlers.Add(handler);
+            }
+        }
+
+        public void RemoveResourceRequestHandler(Action<RequestHandlerContext> handler)
+        {
+            lock (_resourceRequestHandlers)
+            {
+                _resourceRequestHandlers.Remove(handler);
+            }
+        }
+
+        public void AddBeforeBrowseHandler(Action<BeforeBrowseContext> handler)
+        {
+            lock (_beforeBrowseHandlers)
+            {
+                _beforeBrowseHandlers.Add(handler);
+            }
+        }
+
+        public void RemoveBeforeBrowseHandler(Action<BeforeBrowseContext> handler)
+        {
+            lock (_beforeBrowseHandlers)
+            {
+                _beforeBrowseHandlers.Remove(handler);
+            }
+        }
+
+        protected override CefResourceRequestHandler? GetResourceRequestHandler(
+            CefBrowser browser,
+            CefFrame frame,
+            CefRequest request,
+            bool isNavigation,
+            bool isDownload,
+            string requestInitiator,
+            ref bool disableDefaultHandling)
+        {
+            lock (_resourceRequestHandlers)
+            {
+                _sawmill.Debug($"HANDLING REQUEST: {request.Url}");
+
+                var context = new RequestHandlerContext(isNavigation, isDownload, requestInitiator, request);
+
+                foreach (var handler in _resourceRequestHandlers)
+                {
+                    handler(context);
+
+                    if (context.IsHandled)
+                        disableDefaultHandling = true;
+
+                    if (context.IsCancelled)
+                        return null;
+
+                    if (context.Result != null)
+                        return new WrapReaderResourceHandler(context.Result.MakeHandler());
+                }
+            }
+
+            return null;
+        }
+
+        protected override bool OnBeforeBrowse(CefBrowser browser, CefFrame frame, CefRequest request, bool userGesture, bool isRedirect)
+        {
+            lock (_beforeBrowseHandlers)
+            {
+                var context = new BeforeBrowseContext(isRedirect, userGesture, request);
+
+                foreach (var handler in _beforeBrowseHandlers)
+                {
+                    handler(context);
+
+                    if (context.IsCancelled)
+                        return true;
+                }
+            }
+
+            return false;
+        }
+
+        private sealed class WrapReaderResourceHandler : CefResourceRequestHandler
+        {
+            private readonly CefResourceHandler _handler;
+
+            public WrapReaderResourceHandler(CefResourceHandler handler)
+            {
+                _handler = handler;
+            }
+
+            protected override CefCookieAccessFilter? GetCookieAccessFilter(
+                CefBrowser browser,
+                CefFrame frame,
+                CefRequest request)
+            {
+                return null;
+            }
+
+            protected override CefResourceHandler GetResourceHandler(
+                CefBrowser browser,
+                CefFrame frame,
+                CefRequest request)
+            {
+                return _handler;
+            }
+        }
+    }
+}

Robust.Client.Injectors/Program.cs

@@ -29,26 +29,27 @@ namespace Robust.Build.Tasks
         }
     }
 
+    //formatted according to https://github.com/dotnet/msbuild/blob/main/src/Shared/CanonicalError.cs#L57
     class ConsoleBuildEngine : IBuildEngine
     {
         public void LogErrorEvent(BuildErrorEventArgs e)
         {
-            Console.WriteLine($"ERROR: {e.Code} {e.Message} in {e.File} {e.LineNumber}:{e.ColumnNumber}-{e.EndLineNumber}:{e.EndColumnNumber}");
+            Console.WriteLine($"{e.File} ({e.LineNumber},{e.ColumnNumber},{e.EndLineNumber},{e.EndColumnNumber}): XAMLIL ERROR {e.Code}: {e.Message}");
         }
 
         public void LogWarningEvent(BuildWarningEventArgs e)
         {
-            Console.WriteLine($"WARNING: {e.Code} {e.Message} in {e.File} {e.LineNumber}:{e.ColumnNumber}-{e.EndLineNumber}:{e.EndColumnNumber}");
+            Console.WriteLine($"{e.File} ({e.LineNumber},{e.ColumnNumber},{e.EndLineNumber},{e.EndColumnNumber}): XAMLIL WARNING {e.Code}: {e.Message}");
         }
 
         public void LogMessageEvent(BuildMessageEventArgs e)
         {
-            Console.WriteLine($"MESSAGE: {e.Code} {e.Message} in {e.File} {e.LineNumber}:{e.ColumnNumber}-{e.EndLineNumber}:{e.EndColumnNumber}");
+            Console.WriteLine($"{e.File} ({e.LineNumber},{e.ColumnNumber},{e.EndLineNumber},{e.EndColumnNumber}): XAMLIL MESSAGE {e.Code}: {e.Message}");
         }
 
         public void LogCustomEvent(CustomBuildEventArgs e)
         {
-            Console.WriteLine($"CUSTOM: {e.Message}");
+            Console.WriteLine(e.Message);
         }
 
         public bool BuildProjectFile(string projectFileName, string[] targetNames, IDictionary globalProperties,

Robust.Client.Injectors/RobustXamlILCompiler.cs

@@ -1,4 +1,6 @@
-using System.Linq;
+using System.Diagnostics;
+using System.Linq;
+using XamlX;
 using XamlX.Ast;
 using XamlX.Emit;
 using XamlX.IL;
@@ -11,11 +13,14 @@ namespace Robust.Build.Tasks
     /// Emitters & Transformers based on:
     /// - https://github.com/AvaloniaUI/Avalonia/blob/c85fa2b9977d251a31886c2534613b4730fbaeaf/src/Markup/Avalonia.Markup.Xaml.Loader/CompilerExtensions/Transformers/AvaloniaXamlIlRootObjectScopeTransformer.cs
     /// - https://github.com/AvaloniaUI/Avalonia/blob/c85fa2b9977d251a31886c2534613b4730fbaeaf/src/Markup/Avalonia.Markup.Xaml.Loader/CompilerExtensions/Transformers/AddNameScopeRegistration.cs
+    /// - https://github.com/AvaloniaUI/Avalonia/blob/afb8ae6f3c517dae912729511483995b16cb31af/src/Markup/Avalonia.Markup.Xaml.Loader/CompilerExtensions/Transformers/IgnoredDirectivesTransformer.cs
     /// </summary>
     public class RobustXamlILCompiler : XamlILCompiler
     {
         public RobustXamlILCompiler(TransformerConfiguration configuration, XamlLanguageEmitMappings<IXamlILEmitter, XamlILNodeEmitResult> emitMappings, bool fillWithDefaults) : base(configuration, emitMappings, fillWithDefaults)
         {
+            Transformers.Insert(0, new IgnoredDirectivesTransformer());
+
             Transformers.Add(new AddNameScopeRegistration());
             Transformers.Add(new RobustMarkRootObjectScopeNode());
 
@@ -197,5 +202,24 @@ namespace Robust.Build.Tasks
                 }
             }
         }
+
+        class IgnoredDirectivesTransformer : IXamlAstTransformer
+        {
+            public IXamlAstNode Transform(AstTransformationContext context, IXamlAstNode node)
+            {
+                if (node is XamlAstObjectNode astNode)
+                {
+                    astNode.Children.RemoveAll(n =>
+                        n is XamlAstXmlDirective dir &&
+                        dir.Namespace == XamlNamespaces.Xaml2006 &&
+                        (dir.Name == "Class" ||
+                         dir.Name == "Precompile" ||
+                         dir.Name == "FieldModifier" ||
+                         dir.Name == "ClassModifier"));
+                }
+
+                return node;
+            }
+        }
     }
 }

Robust.Client.Injectors/XamlCompiler.cs

@@ -280,8 +280,8 @@ namespace Robust.Build.Tasks
                     }
                     catch (Exception e)
                     {
-                        engine.LogWarningEvent(new BuildWarningEventArgs("XAMLIL", "", res.Uri, 0, 0, 0, 0,
-                            e.ToString(), "", "CompileRobustXaml"));
+                        engine.LogErrorEvent(new BuildErrorEventArgs("XAMLIL", "", res.FilePath, 0, 0, 0, 0,
+                            $"{res.FilePath}: {e.Message}", "", "CompileRobustXaml"));
                     }
                 }
                 return true;

Robust.Client/Audio/Midi/MidiManager.cs

@@ -65,7 +65,7 @@ namespace Robust.Client.Audio.Midi
         [Dependency] private readonly IEntityManager _entityManager = default!;
         [Dependency] private readonly IConfigurationManager _cfgMan = default!;
 
-        private SharedBroadPhaseSystem _broadPhaseSystem = default!;
+        private SharedBroadphaseSystem _broadPhaseSystem = default!;
 
         [ViewVariables]
         public bool IsAvailable
@@ -175,7 +175,7 @@ namespace Robust.Client.Audio.Midi
             _midiThread = new Thread(ThreadUpdate);
             _midiThread.Start();
 
-            _broadPhaseSystem = EntitySystem.Get<SharedBroadPhaseSystem>();
+            _broadPhaseSystem = EntitySystem.Get<SharedBroadphaseSystem>();
             FluidsynthInitialized = true;
         }
 

Robust.Client/BaseClient.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Net;
 using Robust.Client.Debugging;
 using Robust.Client.GameObjects;

Robust.Client/ClientIoC.cs

@@ -25,6 +25,7 @@ using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
 using Robust.Shared.Map;
 using Robust.Shared.Network;
+using Robust.Shared.Physics;
 using Robust.Shared.Players;
 using Robust.Shared.Prototypes;
 using Robust.Shared.Reflection;
@@ -76,6 +77,7 @@ namespace Robust.Client
             IoCManager.Register<IDiscordRichPresence, DiscordRichPresence>();
             IoCManager.Register<IMidiManager, MidiManager>();
             IoCManager.Register<IAuthManager, AuthManager>();
+            IoCManager.Register<IPhysicsManager, PhysicsManager>();
             switch (mode)
             {
                 case GameController.DisplayMode.Headless:

Robust.Client/Console/ClientConsoleHost.cs

@@ -83,6 +83,8 @@ namespace Robust.Client.Console
             OutputText(text, true, true);
         }
 
+        public override event ConAnyCommandCallback? AnyCommandExecuted;
+
         /// <inheritdoc />
         public override void ExecuteCommand(ICommonSession? session, string command)
         {
@@ -103,7 +105,11 @@ namespace Robust.Client.Console
             {
                 var command1 = AvailableCommands[commandName];
                 args.RemoveAt(0);
-                command1.Execute(new ConsoleShell(this, null), command, args.ToArray());
+                var shell = new ConsoleShell(this, null);
+                var cmdArgs = args.ToArray();
+
+                AnyCommandExecuted?.Invoke(shell, commandName, command, cmdArgs);
+                command1.Execute(shell, command, cmdArgs);
             }
             else
                 WriteError(null, "Unknown command: " + commandName);

Robust.Client/Console/Commands/Debug.cs

@@ -27,6 +27,7 @@ using Robust.Shared.Reflection;
 using Robust.Shared.Serialization;
 using Robust.Shared.Utility;
 using Robust.Shared.ViewVariables;
+using static Robust.Client.UserInterface.Controls.BoxContainer;
 
 namespace Robust.Client.Console.Commands
 {
@@ -459,13 +460,18 @@ namespace Robust.Client.Console.Commands
 
         public void Execute(IConsoleShell shell, string argStr, string[] args)
         {
-            var root = IoCManager.Resolve<IUserInterfaceManager>().RootControl;
+            var uiMgr = IoCManager.Resolve<IUserInterfaceManager>();
             var res = IoCManager.Resolve<IResourceManager>();
 
             using (var stream = res.UserData.Create(new ResourcePath("/guidump.txt")))
             using (var writer = new StreamWriter(stream, EncodingHelpers.UTF8))
             {
-                _writeNode(root, 0, writer);
+                foreach (var root in uiMgr.AllRoots)
+                {
+                    writer.WriteLine($"ROOT: {root}");
+                    _writeNode(root, 0, writer);
+                    writer.WriteLine("---------------");
+                }
             }
 
             shell.WriteLine("Saved guidump");
@@ -475,7 +481,7 @@ namespace Robust.Client.Console.Commands
         {
             var indentation = new string(' ', indents * 2);
             writer.WriteLine("{0}{1}", indentation, control);
-            foreach (var (key, value) in _propertyValuesFor(control))
+            foreach (var (key, value) in PropertyValuesFor(control))
             {
                 writer.WriteLine("{2} * {0}: {1}", key, value, indentation);
             }
@@ -486,14 +492,14 @@ namespace Robust.Client.Console.Commands
             }
         }
 
-        private static List<(string, string)> _propertyValuesFor(Control control)
+        internal static List<(string, string)> PropertyValuesFor(Control control)
         {
             var members = new List<(string, string)>();
             var type = control.GetType();
 
             foreach (var fieldInfo in type.GetAllFields())
             {
-                if (fieldInfo.GetCustomAttribute<ViewVariablesAttribute>() == null)
+                if (!ViewVariablesUtility.TryGetViewVariablesAccess(fieldInfo, out _))
                 {
                     continue;
                 }
@@ -503,7 +509,7 @@ namespace Robust.Client.Console.Commands
 
             foreach (var propertyInfo in type.GetAllProperties())
             {
-                if (propertyInfo.GetCustomAttribute<ViewVariablesAttribute>() == null)
+                if (!ViewVariablesUtility.TryGetViewVariablesAccess(propertyInfo, out _))
                 {
                     continue;
                 }
@@ -536,7 +542,10 @@ namespace Robust.Client.Console.Commands
             var scroll = new ScrollContainer();
             tabContainer.AddChild(scroll);
             //scroll.SetAnchorAndMarginPreset(Control.LayoutPreset.Wide);
-            var vBox = new VBoxContainer();
+            var vBox = new BoxContainer
+            {
+                Orientation = LayoutOrientation.Vertical
+            };
             scroll.AddChild(vBox);
 
             var progressBar = new ProgressBar { MaxValue = 10, Value = 5 };
@@ -594,7 +603,10 @@ namespace Robust.Client.Console.Commands
             }
 
             var group = new ButtonGroup();
-            var vBoxRadioButtons = new VBoxContainer();
+            var vBoxRadioButtons = new BoxContainer
+            {
+                Orientation = LayoutOrientation.Vertical
+            };
             for (var i = 0; i < 10; i++)
             {
                 vBoxRadioButtons.AddChild(new Button
@@ -610,8 +622,9 @@ namespace Robust.Client.Console.Commands
 
             TabContainer.SetTabTitle(vBoxRadioButtons, "Radio buttons!!");
 
-            tabContainer.AddChild(new VBoxContainer
+            tabContainer.AddChild(new BoxContainer
             {
+                Orientation = LayoutOrientation.Vertical,
                 Name = "Slider",
                 Children =
                 {
@@ -863,7 +876,7 @@ namespace Robust.Client.Console.Commands
             var chunkIndex = grid.LocalToChunkIndices(grid.MapToGrid(mousePos));
             var chunk = internalGrid.GetChunk(chunkIndex);
 
-            shell.WriteLine($"worldBounds: {chunk.CalcWorldBounds()} localBounds: {chunk.CalcLocalBounds()}");
+            shell.WriteLine($"worldBounds: {chunk.CalcWorldAABB()} localBounds: {chunk.CalcLocalBounds()}");
         }
     }
 

Robust.Client/Console/Commands/GridChunkBBCommand.cs

@@ -0,0 +1,17 @@
+using Robust.Client.GameObjects;
+using Robust.Shared.Console;
+using Robust.Shared.GameObjects;
+
+namespace Robust.Client.Console.Commands
+{
+    public class GridChunkBBCommand : IConsoleCommand
+    {
+        public string Command => "showchunkbb";
+        public string Description => "Displays chunk bounds for the purposes of rendering";
+        public string Help => $"{Command}";
+        public void Execute(IConsoleShell shell, string argStr, string[] args)
+        {
+            EntitySystem.Get<GridChunkBoundsDebugSystem>().Enabled ^= true;
+        }
+    }
+}

Robust.Client/Console/ScriptConsoleClient.cs

@@ -13,10 +13,11 @@ using Microsoft.CodeAnalysis.Text;
 using Robust.Client.UserInterface.CustomControls;
 using Robust.Client.ViewVariables;
 using Robust.Shared.IoC;
-using Robust.Shared.Maths;
 using Robust.Shared.Reflection;
 using Robust.Shared.Scripting;
 using Robust.Shared.Utility;
+using SixLabors.ImageSharp;
+using Color = Robust.Shared.Maths.Color;
 
 #nullable enable
 
@@ -116,7 +117,7 @@ namespace Robust.Client.Console
             }
             else
             {
-                var options = ScriptInstanceShared.GetScriptOptions(_reflectionManager);
+                var options = ScriptInstanceShared.GetScriptOptions(_reflectionManager).AddReferences(typeof(Image).Assembly);
                 newScript = CSharpScript.Create(code, options, typeof(ScriptGlobals));
             }
 

Robust.Client/Console/WatchWindow.cs

@@ -11,6 +11,7 @@ using Robust.Shared.IoC;
 using Robust.Shared.Reflection;
 using Robust.Shared.Scripting;
 using Robust.Shared.Timing;
+using static Robust.Client.UserInterface.Controls.BoxContainer;
 
 namespace Robust.Client.Console
 {
@@ -18,7 +19,7 @@ namespace Robust.Client.Console
     {
         private readonly IReflectionManager _reflectionManager;
 
-        private readonly VBoxContainer _watchesVBox;
+        private readonly BoxContainer _watchesVBox;
         private readonly LineEdit _addWatchEdit;
         private readonly Button _addWatchButton;
 
@@ -31,17 +32,20 @@ namespace Robust.Client.Console
 
             Title = "Watch Window";
 
-            var mainVBox = new VBoxContainer
+            var mainVBox = new BoxContainer
             {
+                Orientation = LayoutOrientation.Vertical,
                 MinSize = (500, 300),
                 Children =
                 {
-                    (_watchesVBox = new VBoxContainer
+                    (_watchesVBox = new BoxContainer
                     {
+                        Orientation = LayoutOrientation.Vertical,
                         VerticalExpand = true
                     }),
-                    new HBoxContainer
+                    new BoxContainer
                     {
+                        Orientation = LayoutOrientation.Horizontal,
                         Children =
                         {
                             (_addWatchEdit = new HistoryLineEdit
@@ -105,8 +109,9 @@ namespace Robust.Client.Console
                 Button delButton;
                 _runner = runner;
 
-                AddChild(new HBoxContainer
+                AddChild(new BoxContainer
                 {
+                    Orientation = LayoutOrientation.Horizontal,
                     Children =
                     {
                         (_outputLabel = new Label
@@ -166,8 +171,9 @@ namespace Robust.Client.Console
             public CompilationErrorControl(string message)
             {
                 Button delButton;
-                AddChild(new HBoxContainer
+                AddChild(new BoxContainer
                 {
+                    Orientation = LayoutOrientation.Horizontal,
                     Children =
                     {
                         new Label

Robust.Client/Debugging/DebugDrawing.cs

@@ -162,12 +162,13 @@ namespace Robust.Client.Debugging
                 if (viewport.IsEmpty()) return;
 
                 var mapId = _eyeManager.CurrentMap;
-                var sleepThreshold = IoCManager.Resolve<IConfigurationManager>().GetCVar(CVars.TimeToSleep);
                 var colorEdge = Color.Red.WithAlpha(0.33f);
                 var drawnJoints = new HashSet<Joint>();
 
-                foreach (var physBody in EntitySystem.Get<SharedBroadPhaseSystem>().GetCollidingEntities(mapId, viewport))
+                foreach (var physBody in EntitySystem.Get<SharedBroadphaseSystem>().GetCollidingEntities(mapId, viewport))
                 {
+                    if (physBody.Owner.HasComponent<MapGridComponent>()) continue;
+
                     // all entities have a TransformComponent
                     var transform = physBody.Owner.Transform;
 

Robust.Client/Debugging/DebugPhysicsSystem.cs

@@ -28,6 +28,7 @@ using Robust.Shared.Enums;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
 using Robust.Shared.Maths;
+using Robust.Shared.Physics;
 using Robust.Shared.Physics.Collision;
 using Robust.Shared.Physics.Dynamics;
 using Robust.Shared.Physics.Dynamics.Contacts;
@@ -40,6 +41,8 @@ namespace Robust.Client.Debugging
          * Used for debugging shapes, controllers, joints, contacts
          */
 
+        [Dependency] private readonly IPhysicsManager _physicsManager = default!;
+
         private const int MaxContactPoints = 2048;
         internal int PointCount;
 
@@ -79,8 +82,7 @@ namespace Robust.Client.Debugging
                 CollisionManager.GetPointStates(out state1, out state2, oldManifold, manifold);
 
                 Span<Vector2> points = stackalloc Vector2[2];
-                Vector2 normal;
-                contact.GetWorldManifold(out normal, points);
+                contact.GetWorldManifold(_physicsManager, out var normal, points);
 
                 for (int i = 0; i < manifold.PointCount && PointCount < MaxContactPoints; ++i)
                 {

Robust.Client/GameController/GameController.cs

@@ -255,6 +255,15 @@ namespace Robust.Client
                 _configurationManager.OverrideConVars(_commandLineArgs.CVars);
             }
 
+            {
+                // Handle GameControllerOptions implicit CVar overrides.
+                _configurationManager.OverrideConVars(new []
+                {
+                    (CVars.DisplayWindowIconSet.Name, options.WindowIconSet.ToString()),
+                    (CVars.DisplaySplashLogo.Name, options.SplashLogo.ToString())
+                });
+            }
+
             ProfileOptSetup.Setup(_configurationManager);
 
             _resourceCache.Initialize(Options.LoadConfigAndUserData ? userDataDir : null);
@@ -472,6 +481,8 @@ namespace Robust.Client
 
         internal void Cleanup()
         {
+            _modLoader.Shutdown();
+
             _networkManager.Shutdown("Client shutting down");
             _midiManager.Shutdown();
             IoCManager.Resolve<IEntityLookup>().Shutdown();

Robust.Client/GameControllerOptions.cs

@@ -52,6 +52,16 @@ namespace Robust.Client
         /// </summary>
         public ResourcePath PrototypeDirectory { get; init; } = new(@"/Prototypes/");
 
+        /// <summary>
+        /// Directory resource path containing window icons to load.
+        /// </summary>
+        public ResourcePath WindowIconSet { get; init; } = new("/Textures/Logo/icon");
+
+        /// <summary>
+        /// Resource path for splash image to show when the game starts up.
+        /// </summary>
+        public ResourcePath SplashLogo { get; init; } = new("/Textures/Logo/logo.png");
+
         /// <summary>
         ///     Whether to disable mounting the "Resources/" folder on FULL_RELEASE.
         /// </summary>

Robust.Client/GameObjects/ClientComponentFactory.cs

@@ -25,6 +25,7 @@ namespace Robust.Client.GameObjects
             RegisterClass<InputComponent>();
             RegisterClass<SpriteComponent>();
             RegisterClass<ClientOccluderComponent>();
+            RegisterClass<OccluderTreeComponent>();
             RegisterClass<EyeComponent>();
             RegisterClass<AppearanceComponent>();
             RegisterClass<AppearanceTestComponent>();

Robust.Client/GameObjects/Components/Input/InputComponent.cs

@@ -1,7 +1,5 @@
 using Robust.Shared.GameObjects;
 using Robust.Shared.Input;
-using Robust.Shared.Prototypes;
-using Robust.Shared.Serialization;
 using Robust.Shared.Serialization.Manager.Attributes;
 using Robust.Shared.ViewVariables;
 
@@ -10,7 +8,7 @@ namespace Robust.Client.GameObjects
     /// <summary>
     ///     Defines data fields used in the <see cref="InputSystem"/>.
     /// </summary>
-    class InputComponent : Component
+    public class InputComponent : Component
     {
         /// <inheritdoc />
         public override string Name => "Input";

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

@@ -228,6 +228,6 @@ namespace Robust.Client.GameObjects
         /// <summary>
         ///     Calculate sprite bounding box in world-space coordinates.
         /// </summary>
-        Box2 CalculateBoundingBox();
+        Box2 CalculateBoundingBox(Vector2 worldPos);
     }
 }

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

@@ -0,0 +1,90 @@
+using System.Collections.Generic;
+using Robust.Client.Graphics;
+using Robust.Client.Graphics.Clyde;
+using Robust.Shared.Console;
+using Robust.Shared.Enums;
+using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.Maths;
+using Robust.Shared.Utility;
+
+namespace Robust.Client.GameObjects
+{
+    public sealed class ShowSpriteBBCommand : IConsoleCommand
+    {
+        public string Command => "showspritebb";
+        public string Description => "Toggle whether sprite bounds are shown";
+        public string Help => $"{Command}";
+        public void Execute(IConsoleShell shell, string argStr, string[] args)
+        {
+            EntitySystem.Get<SpriteBoundsSystem>().Enabled ^= true;
+        }
+    }
+
+    public sealed class SpriteBoundsSystem : EntitySystem
+    {
+        private SpriteBoundsOverlay? _overlay;
+
+        public bool Enabled
+        {
+            get => _enabled;
+            set
+            {
+                if (_enabled == value) return;
+
+                _enabled = value;
+
+                if (_enabled)
+                {
+                    DebugTools.AssertNull(_overlay);
+                    var overlayManager = IoCManager.Resolve<IOverlayManager>();
+                    _overlay = new SpriteBoundsOverlay(EntitySystem.Get<RenderingTreeSystem>(), IoCManager.Resolve<IEyeManager>());
+                    overlayManager.AddOverlay(_overlay);
+                }
+                else
+                {
+                    if (_overlay == null) return;
+                    var overlayManager = IoCManager.Resolve<IOverlayManager>();
+                    overlayManager.RemoveOverlay(_overlay);
+                    _overlay = null;
+                }
+            }
+        }
+
+        private bool _enabled;
+    }
+
+    public class SpriteBoundsOverlay : Overlay
+    {
+        public override OverlaySpace Space => OverlaySpace.WorldSpace;
+
+        private readonly IEyeManager _eyeManager = default!;
+        private RenderingTreeSystem _renderTree;
+
+        public SpriteBoundsOverlay(RenderingTreeSystem renderTree, IEyeManager eyeManager)
+        {
+            _renderTree = renderTree;
+            _eyeManager = eyeManager;
+        }
+
+        protected internal override void Draw(in OverlayDrawArgs args)
+        {
+            var handle = args.WorldHandle;
+            var currentMap = _eyeManager.CurrentMap;
+            var viewport = _eyeManager.GetWorldViewport();
+
+            foreach (var comp in _renderTree.GetRenderTrees(currentMap, viewport))
+            {
+                var localAABB = viewport.Translated(-comp.Owner.Transform.WorldPosition);
+
+                foreach (var sprite in comp.SpriteTree.QueryAabb(localAABB))
+                {
+                    var worldPos = sprite.Owner.Transform.WorldPosition;
+                    var bounds = sprite.CalculateBoundingBox(worldPos);
+                    handle.DrawRect(bounds, Color.Red.WithAlpha(0.2f));
+                    handle.DrawRect(bounds.Scale(0.2f).Translated(-new Vector2(0f, bounds.Extents.Y)), Color.Blue.WithAlpha(0.5f));
+                }
+            }
+        }
+    }
+}

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

@@ -365,7 +365,7 @@ namespace Robust.Client.GameObjects
                     }
                     else
                     {
-                        Logger.ErrorS(LogCategory, "Unable to load RSI '{0}'. Trace:\n{1}", rsiPath);
+                        Logger.ErrorS(LogCategory, "Unable to load RSI '{0}'.", rsiPath);
                     }
                 }
             }
@@ -1212,9 +1212,9 @@ namespace Robust.Client.GameObjects
         public IEnumerable<ISpriteLayer> AllLayers => Layers;
 
         // Lobby SpriteView rendering path
-        internal void Render(DrawingHandleWorld drawingHandle, Angle worldRotation, Direction? overrideDirection = null)
+        internal void Render(DrawingHandleWorld drawingHandle, Angle eyeRotation, Angle worldRotation, Direction? overrideDirection = null)
         {
-            RenderInternal(drawingHandle, worldRotation, Vector2.Zero, overrideDirection);
+            RenderInternal(drawingHandle, eyeRotation, worldRotation, Vector2.Zero, overrideDirection);
         }
 
         [DataField("noRot")]
@@ -1239,7 +1239,7 @@ namespace Robust.Client.GameObjects
         public bool EnableDirectionOverride { get => _enableOverrideDirection; set => _enableOverrideDirection = value; }
 
         // Sprite rendering path
-        internal void Render(DrawingHandleWorld drawingHandle, in Angle worldRotation, in Vector2 worldPosition)
+        internal void Render(DrawingHandleWorld drawingHandle, Angle eyeRotation, in Angle worldRotation, in Vector2 worldPosition)
         {
             Direction? overrideDir = null;
             if (_enableOverrideDirection)
@@ -1247,16 +1247,18 @@ namespace Robust.Client.GameObjects
                 overrideDir = _overrideDirection;
             }
 
-            RenderInternal(drawingHandle, worldRotation, worldPosition, overrideDir);
+            RenderInternal(drawingHandle, eyeRotation, worldRotation, worldPosition, overrideDir);
         }
 
-        private void CalcModelMatrix(int numDirs, Angle worldRotation, Vector2 worldPosition, out Matrix3 modelMatrix)
+        private void CalcModelMatrix(int numDirs, Angle eyeRotation, Angle worldRotation, Vector2 worldPosition, out Matrix3 modelMatrix)
         {
             Angle angle;
 
             if (_screenLock)
             {
-                angle = Angle.Zero;
+                // Negate the eye rotation in the model matrix, so that later when the view matrix is applied the
+                // sprite will be locked upright to the screen
+                angle = new Angle(-eyeRotation.Theta);
             }
             else
             {
@@ -1267,7 +1269,7 @@ namespace Robust.Client.GameObjects
             modelMatrix = Matrix3.CreateTransform(in worldPosition, in sWorldRotation);
         }
 
-        private void RenderInternal(DrawingHandleWorld drawingHandle, Angle worldRotation, Vector2 worldPosition, Direction? overrideDirection)
+        private void RenderInternal(DrawingHandleWorld drawingHandle, Angle eyeRotation, Angle worldRotation, Vector2 worldPosition, Direction? overrideDirection)
         {
             var localMatrix = GetLocalMatrix();
 
@@ -1280,7 +1282,7 @@ namespace Robust.Client.GameObjects
 
                 var numDirs = GetLayerDirectionCount(layer);
 
-                CalcModelMatrix(numDirs, worldRotation, worldPosition, out var modelMatrix);
+                CalcModelMatrix(numDirs, eyeRotation, worldRotation, worldPosition, out var modelMatrix);
                 Matrix3.Multiply(ref localMatrix, ref modelMatrix, out var transformMatrix);
                 drawingHandle.SetTransform(in transformMatrix);
 
@@ -1510,6 +1512,11 @@ namespace Robust.Client.GameObjects
 
         private void QueueUpdateIsInert()
         {
+            // Look this was an easy way to get bounds checks for layer updates.
+            // If you really want it optimal you'll need to comb through all 2k lines of spritecomponent.
+            if (Owner?.EntityManager?.EventBus != null)
+                UpdateBounds();
+
             if (_inertUpdateQueued)
                 return;
 
@@ -1624,11 +1631,11 @@ namespace Robust.Client.GameObjects
         }
 
         /// <inheritdoc/>
-        public Box2 CalculateBoundingBox()
+        public Box2 CalculateBoundingBox(Vector2 worldPos)
         {
             // fast check for empty sprites
             if (Layers.Count == 0)
-                return new Box2();
+                return new Box2(worldPos, worldPos);
 
             // we need to calculate bounding box taking into account all nested layers
             // because layers can have offsets, scale or rotation we need to calculate a new BB
@@ -1651,11 +1658,15 @@ namespace Robust.Client.GameObjects
                 new Box2Rotated(spriteBox, Rotation).CalcBoundingBox() : spriteBox;
 
             // move it all to world transform system (with sprite offset)
-            var worldPosition = Owner.Transform.WorldPosition;
-            var worldBB = spriteBB.Translated(Offset + worldPosition);
+            var worldBB = spriteBB.Translated(Offset + worldPos);
             return worldBB;
         }
 
+        internal void UpdateBounds()
+        {
+            Owner.EntityManager.EventBus.RaiseLocalEvent(Owner.Uid, new SpriteUpdateEvent());
+        }
+
         /// <summary>
         ///     Enum to "offset" a cardinal direction.
         /// </summary>
@@ -1711,7 +1722,19 @@ namespace Robust.Client.GameObjects
             public bool AutoAnimated = true;
 
             [ViewVariables(VVAccess.ReadWrite)]
-            public Vector2 Offset { get; set; }
+            public Vector2 Offset
+            {
+                get => _offset;
+                set
+                {
+                    if (_offset.EqualsApprox(value)) return;
+
+                    _offset = value;
+                    _parent.UpdateBounds();
+                }
+            }
+
+            private Vector2 _offset;
 
             [ViewVariables]
             public DirectionOffset DirOffset { get; set; }
@@ -1983,7 +2006,6 @@ namespace Robust.Client.GameObjects
                 // TODO: scale & rotation for layers is currently unimplemented.
                 return Box2.CenteredAround(Offset, PixelSize / EyeManager.PixelsPerMeter);
             }
-
         }
 
         void IAnimationProperties.SetAnimatableProperty(string name, object value)

Robust.Client/GameObjects/Components/RenderingTreeComponent.cs

@@ -15,29 +15,45 @@ namespace Robust.Client.GameObjects
         private static Box2 SpriteAabbFunc(in SpriteComponent value)
         {
             var worldPos = value.Owner.Transform.WorldPosition;
-            return new Box2(worldPos, worldPos);
+            var bounds = value.CalculateBoundingBox(worldPos);
+            var tree = RenderingTreeSystem.GetRenderTree(value.Owner);
+
+            var offset = -tree?.Owner.Transform.WorldPosition ?? Vector2.Zero;
+
+            return bounds.Translated(offset);
         }
 
         private static Box2 LightAabbFunc(in PointLightComponent value)
         {
             var worldPos = value.Owner.Transform.WorldPosition;
-
+            var tree = RenderingTreeSystem.GetRenderTree(value.Owner);
             var boxSize = value.Radius * 2;
-            return Box2.CenteredAround(worldPos, (boxSize, boxSize));
+
+            var pos = worldPos - tree?.Owner.Transform.WorldPosition ?? Vector2.Zero;
+
+            return Box2.CenteredAround(pos, (boxSize, boxSize));
         }
 
         internal static Box2 SpriteAabbFunc(SpriteComponent value, Vector2? worldPos = null)
         {
             worldPos ??= value.Owner.Transform.WorldPosition;
+            var bounds = value.CalculateBoundingBox(worldPos.Value);
+            var tree = RenderingTreeSystem.GetRenderTree(value.Owner);
 
-            return new Box2(worldPos.Value, worldPos.Value);
+            var offset = -tree?.Owner.Transform.WorldPosition ?? Vector2.Zero;
+
+            return bounds.Translated(offset);
         }
 
         internal static Box2 LightAabbFunc(PointLightComponent value, Vector2? worldPos = null)
         {
             worldPos ??= value.Owner.Transform.WorldPosition;
+            var tree = RenderingTreeSystem.GetRenderTree(value.Owner);
             var boxSize = value.Radius * 2;
-            return Box2.CenteredAround(worldPos.Value, (boxSize, boxSize));
+
+            var pos = worldPos - tree?.Owner.Transform.WorldPosition ?? Vector2.Zero;
+
+            return Box2.CenteredAround(pos, (boxSize, boxSize));
         }
     }
 }

Robust.Client/GameObjects/EntitySystems/AudioSystem.cs

@@ -23,8 +23,7 @@ namespace Robust.Client.GameObjects
         [Dependency] private readonly IClydeAudio _clyde = default!;
         [Dependency] private readonly IEyeManager _eyeManager = default!;
         [Dependency] private readonly IEntityManager _entityManager = default!;
-
-        private SharedBroadPhaseSystem _broadPhaseSystem = default!;
+        [Dependency] private readonly SharedBroadphaseSystem _broadPhaseSystem = default!;
 
         private readonly List<PlayingStream> _playingClydeStreams = new();
 
@@ -38,7 +37,6 @@ namespace Robust.Client.GameObjects
             SubscribeNetworkEvent<StopAudioMessageClient>(StopAudioMessageHandler);
 
             SubscribeLocalEvent<SoundSystem.QueryAudioSystem>((ev => ev.Audio = this));
-            _broadPhaseSystem = Get<SharedBroadPhaseSystem>();
         }
 
         private void StopAudioMessageHandler(StopAudioMessageClient ev)
@@ -301,7 +299,7 @@ namespace Robust.Client.GameObjects
             if (!source.SetPosition(coordinates.ToMapPos(EntityManager)))
             {
                 source.Dispose();
-                Logger.Warning("Can't play positional audio \"{stream.Name}\", can't set position.");
+                Logger.Warning($"Can't play positional audio \"{stream.Name}\", can't set position.");
                 return null;
             }
 

Robust.Client/GameObjects/EntitySystems/ClientContainerSystem.cs

@@ -1,94 +0,0 @@
-using System.Collections.Generic;
-using Robust.Shared.Containers;
-using Robust.Shared.GameObjects;
-
-namespace Robust.Client.GameObjects
-{
-    public class ClientContainerSystem : ContainerSystem
-    {
-        private readonly HashSet<IEntity> _updateQueue = new();
-
-        public override void Initialize()
-        {
-            base.Initialize();
-
-            SubscribeLocalEvent<UpdateContainerOcclusionMessage>(UpdateContainerOcclusion);
-
-            UpdatesBefore.Add(typeof(SpriteSystem));
-        }
-
-        private void UpdateContainerOcclusion(UpdateContainerOcclusionMessage ev)
-        {
-            _updateQueue.Add(ev.Entity);
-        }
-
-        public override void FrameUpdate(float frameTime)
-        {
-            base.FrameUpdate(frameTime);
-
-            foreach (var toUpdate in _updateQueue)
-            {
-                if (toUpdate.Deleted)
-                {
-                    continue;
-                }
-
-                UpdateEntityRecursively(toUpdate);
-            }
-
-            _updateQueue.Clear();
-        }
-
-        private static void UpdateEntityRecursively(IEntity entity)
-        {
-            // TODO: Since we are recursing down,
-            // we could cache ShowContents data here to speed it up for children.
-            // Am lazy though.
-            UpdateEntity(entity);
-
-            foreach (var child in entity.Transform.Children)
-            {
-                UpdateEntityRecursively(child.Owner);
-            }
-        }
-
-        private static void UpdateEntity(IEntity entity)
-        {
-            if (entity.TryGetComponent(out SpriteComponent? sprite))
-            {
-                sprite.ContainerOccluded = false;
-
-                // We have to recursively scan for containers upwards in case of nested containers.
-                var tempParent = entity;
-                while (tempParent.TryGetContainer(out var container))
-                {
-                    if (!container.ShowContents)
-                    {
-                        sprite.ContainerOccluded = true;
-                        break;
-                    }
-
-                    tempParent = container.Owner;
-                }
-            }
-
-            if (entity.TryGetComponent(out PointLightComponent? light))
-            {
-                light.ContainerOccluded = false;
-
-                // We have to recursively scan for containers upwards in case of nested containers.
-                var tempParent = entity;
-                while (tempParent.TryGetContainer(out var container))
-                {
-                    if (container.OccludesLight)
-                    {
-                        light.ContainerOccluded = true;
-                        break;
-                    }
-
-                    tempParent = container.Owner;
-                }
-            }
-        }
-    }
-}

Robust.Client/GameObjects/EntitySystems/ClientOccluderSystem.cs

@@ -62,7 +62,7 @@ namespace Robust.Client.GameObjects
             }
         }
 
-        private static void HandleAnchorChanged(EntityUid uid, ClientOccluderComponent component, AnchorStateChangedEvent args)
+        private static void HandleAnchorChanged(EntityUid uid, ClientOccluderComponent component, ref AnchorStateChangedEvent args)
         {
             component.AnchorStateChanged();
         }

Robust.Client/GameObjects/EntitySystems/ContainerSystem.cs

@@ -0,0 +1,237 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Robust.Shared.Containers;
+using Robust.Shared.GameObjects;
+using Robust.Shared.GameStates;
+using Robust.Shared.IoC;
+using Robust.Shared.Serialization;
+using static Robust.Shared.Containers.ContainerManagerComponent;
+
+namespace Robust.Client.GameObjects
+{
+    public class ContainerSystem : SharedContainerSystem
+    {
+        [Dependency] private readonly IRobustSerializer _serializer = default!;
+        [Dependency] private readonly IDynamicTypeFactoryInternal _dynFactory = default!;
+
+        private readonly HashSet<IEntity> _updateQueue = new();
+
+        public readonly Dictionary<EntityUid, IContainer> ExpectedEntities = new();
+
+        public override void Initialize()
+        {
+            base.Initialize();
+
+            SubscribeLocalEvent<UpdateContainerOcclusionMessage>(UpdateContainerOcclusion);
+            SubscribeLocalEvent<EntityInitializedMessage>(HandleEntityInitialized);
+            SubscribeLocalEvent<ContainerManagerComponent, ComponentHandleState>(HandleComponentState);
+
+            UpdatesBefore.Add(typeof(SpriteSystem));
+        }
+
+        private void UpdateContainerOcclusion(UpdateContainerOcclusionMessage ev)
+        {
+            _updateQueue.Add(ev.Entity);
+        }
+
+        private void HandleEntityInitialized(EntityInitializedMessage ev)
+        {
+            if (!ExpectedEntities.TryGetValue(ev.Entity.Uid, out var container))
+                return;
+
+            RemoveExpectedEntity(ev.Entity.Uid);
+
+            if (container.Deleted)
+                return;
+
+            container.Insert(ev.Entity);
+        }
+
+        private void HandleComponentState(EntityUid uid, ContainerManagerComponent component, ComponentHandleState args)
+        {
+            if (args.Current is not ContainerManagerComponentState cast)
+                return;
+
+            // Delete now-gone containers.
+            List<string>? toDelete = null;
+            foreach (var (id, container) in component.Containers)
+            {
+                if (!cast.ContainerSet.Any(data => data.Id == id))
+                {
+                    container.Shutdown();
+                    toDelete ??= new List<string>();
+                    toDelete.Add(id);
+                }
+            }
+
+            if (toDelete != null)
+            {
+                foreach (var dead in toDelete)
+                {
+                    component.Containers.Remove(dead);
+                }
+            }
+
+            // Add new containers and update existing contents.
+
+            foreach (var (containerType, id, showEnts, occludesLight, entityUids) in cast.ContainerSet)
+            {
+                if (!component.Containers.TryGetValue(id, out var container))
+                {
+                    container = ContainerFactory(component, containerType, id);
+                    component.Containers.Add(id, container);
+                }
+
+                // sync show flag
+                container.ShowContents = showEnts;
+                container.OccludesLight = occludesLight;
+
+                // Remove gone entities.
+                List<IEntity>? toRemove = null;
+                foreach (var entity in container.ContainedEntities)
+                {
+                    if (!entityUids.Contains(entity.Uid))
+                    {
+                        toRemove ??= new List<IEntity>();
+                        toRemove.Add(entity);
+                    }
+                }
+
+                if (toRemove != null)
+                {
+                    foreach (var goner in toRemove)
+                        container.Remove(goner);
+                }
+
+                // Remove entities that were expected, but have been removed from the container.
+                List<EntityUid>? removedExpected = null;
+                foreach (var entityUid in container.ExpectedEntities)
+                {
+                    if (!entityUids.Contains(entityUid))
+                    {
+                        removedExpected ??= new List<EntityUid>();
+                        removedExpected.Add(entityUid);
+                    }
+                }
+
+                if (removedExpected != null)
+                {
+                    foreach (var entityUid in removedExpected)
+                        RemoveExpectedEntity(entityUid);
+                }
+
+                // Add new entities.
+                foreach (var entityUid in entityUids)
+                {
+                    if (!EntityManager.TryGetEntity(entityUid, out var entity))
+                    {
+                        AddExpectedEntity(entityUid, container);
+                        continue;
+                    }
+
+                    if (!container.ContainedEntities.Contains(entity))
+                        container.Insert(entity);
+                }
+            }
+        }
+
+        private IContainer ContainerFactory(ContainerManagerComponent component, string containerType, string id)
+        {
+            var type = _serializer.FindSerializedType(typeof(IContainer), containerType);
+            if (type is null) throw new ArgumentException($"Container of type {containerType} for id {id} cannot be found.");
+
+            var newContainer = _dynFactory.CreateInstanceUnchecked<BaseContainer>(type);
+            newContainer.ID = id;
+            newContainer.Manager = component;
+            return newContainer;
+        }
+
+        public void AddExpectedEntity(EntityUid uid, IContainer container)
+        {
+            if (ExpectedEntities.ContainsKey(uid))
+                return;
+
+            ExpectedEntities.Add(uid, container);
+            container.ExpectedEntities.Add(uid);
+        }
+
+        public void RemoveExpectedEntity(EntityUid uid)
+        {
+            if (!ExpectedEntities.TryGetValue(uid, out var container))
+                return;
+
+            ExpectedEntities.Remove(uid);
+            container.ExpectedEntities.Remove(uid);
+        }
+
+        public override void FrameUpdate(float frameTime)
+        {
+            base.FrameUpdate(frameTime);
+
+            foreach (var toUpdate in _updateQueue)
+            {
+                if (toUpdate.Deleted)
+                {
+                    continue;
+                }
+
+                UpdateEntityRecursively(toUpdate);
+            }
+
+            _updateQueue.Clear();
+        }
+
+        private static void UpdateEntityRecursively(IEntity entity)
+        {
+            // TODO: Since we are recursing down,
+            // we could cache ShowContents data here to speed it up for children.
+            // Am lazy though.
+            UpdateEntity(entity);
+
+            foreach (var child in entity.Transform.Children)
+            {
+                UpdateEntityRecursively(child.Owner);
+            }
+        }
+
+        private static void UpdateEntity(IEntity entity)
+        {
+            if (entity.TryGetComponent(out SpriteComponent? sprite))
+            {
+                sprite.ContainerOccluded = false;
+
+                // We have to recursively scan for containers upwards in case of nested containers.
+                var tempParent = entity;
+                while (tempParent.TryGetContainer(out var container))
+                {
+                    if (!container.ShowContents)
+                    {
+                        sprite.ContainerOccluded = true;
+                        break;
+                    }
+
+                    tempParent = container.Owner;
+                }
+            }
+
+            if (entity.TryGetComponent(out PointLightComponent? light))
+            {
+                light.ContainerOccluded = false;
+
+                // We have to recursively scan for containers upwards in case of nested containers.
+                var tempParent = entity;
+                while (tempParent.TryGetContainer(out var container))
+                {
+                    if (container.OccludesLight)
+                    {
+                        light.ContainerOccluded = true;
+                        break;
+                    }
+
+                    tempParent = container.Owner;
+                }
+            }
+        }
+    }
+}

Robust.Client/GameObjects/EntitySystems/GridChunkBoundsDebugSystem.cs

@@ -0,0 +1,90 @@
+using Robust.Client.Graphics;
+using Robust.Shared.Enums;
+using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.Map;
+using Robust.Shared.Maths;
+using Robust.Shared.Utility;
+
+namespace Robust.Client.GameObjects
+{
+    public class GridChunkBoundsDebugSystem : EntitySystem
+    {
+        private GridChunkBoundsOverlay? _overlay;
+
+        public bool Enabled
+        {
+            get => _enabled;
+            set
+            {
+                if (_enabled == value) return;
+
+                _enabled = value;
+
+                if (_enabled)
+                {
+                    DebugTools.Assert(_overlay == null);
+                    _overlay = new GridChunkBoundsOverlay(
+                        IoCManager.Resolve<IEntityManager>(),
+                        IoCManager.Resolve<IEyeManager>(),
+                        IoCManager.Resolve<IMapManager>());
+
+                    IoCManager.Resolve<IOverlayManager>().AddOverlay(_overlay);
+                }
+                else
+                {
+                    IoCManager.Resolve<IOverlayManager>().RemoveOverlay(_overlay!);
+                    _overlay = null;
+                }
+            }
+        }
+
+        private bool _enabled;
+    }
+
+    internal sealed class GridChunkBoundsOverlay : Overlay
+    {
+        private readonly IEntityManager _entityManager;
+        private readonly IEyeManager _eyeManager;
+        private readonly IMapManager _mapManager;
+
+        public override OverlaySpace Space => OverlaySpace.WorldSpace;
+
+        public GridChunkBoundsOverlay(IEntityManager entManager, IEyeManager eyeManager, IMapManager mapManager)
+        {
+            _entityManager = entManager;
+            _eyeManager = eyeManager;
+            _mapManager = mapManager;
+        }
+
+        protected internal override void Draw(in OverlayDrawArgs args)
+        {
+            var currentMap = _eyeManager.CurrentMap;
+            var viewport = _eyeManager.GetWorldViewport();
+
+            foreach (var grid in _mapManager.FindGridsIntersecting(currentMap, viewport))
+            {
+                var mapGrid = (IMapGridInternal) grid;
+                var gridEnt = _entityManager.GetEntity(grid.GridEntityId);
+
+                var worldPos = gridEnt.Transform.WorldPosition;
+                var worldRot = gridEnt.Transform.WorldRotation;
+
+                foreach (var (_, chunk) in mapGrid.GetMapChunks())
+                {
+                    var chunkBounds = chunk.CalcWorldBounds(worldPos, worldRot);
+                    var aabb = chunkBounds.CalcBoundingBox();
+
+                    // Calc world bounds for chunk.
+                    if (!aabb.Intersects(in viewport))
+                    {
+                        continue;
+                    }
+
+                    args.WorldHandle.DrawRect(chunkBounds, Color.Green.WithAlpha(0.2f), true);
+                    args.WorldHandle.DrawRect(aabb, Color.Red, false);
+                }
+            }
+        }
+    }
+}

Robust.Client/GameObjects/EntitySystems/GridFixtureSystem.cs

@@ -0,0 +1,9 @@
+using Robust.Shared.GameObjects;
+
+namespace Robust.Client.GameObjects
+{
+    internal sealed class GridFixtureSystem : SharedGridFixtureSystem
+    {
+
+    }
+}

Robust.Client/GameObjects/EntitySystems/MapSystem.cs

@@ -0,0 +1,9 @@
+using Robust.Shared.GameObjects;
+
+namespace Robust.Client.GameObjects
+{
+    internal sealed class MapSystem : SharedMapSystem
+    {
+
+    }
+}

Robust.Client/GameObjects/EntitySystems/RenderingTreeSystem.cs

@@ -41,22 +41,12 @@ namespace Robust.Client.GameObjects
         {
             if (mapId == MapId.Nullspace) yield break;
 
-            var enclosed = false;
-
             foreach (var grid in _mapManager.FindGridsIntersecting(mapId, worldAABB))
             {
                 yield return EntityManager.GetEntity(grid.GridEntityId).GetComponent<RenderingTreeComponent>();
-
-                // if we're enclosed then we know no other grids relevant + don't need the map's rendertree
-                if (grid.WorldBounds.Encloses(in worldAABB))
-                {
-                    enclosed = true;
-                    break;
-                }
             }
 
-            if (!enclosed)
-                yield return _mapManager.GetMapEntity(mapId).GetComponent<RenderingTreeComponent>();
+            yield return _mapManager.GetMapEntity(mapId).GetComponent<RenderingTreeComponent>();
         }
 
         internal IEnumerable<DynamicTree<SpriteComponent>> GetSpriteTrees(MapId mapId, Box2 worldAABB)
@@ -118,7 +108,7 @@ namespace Robust.Client.GameObjects
             QueueSpriteUpdate(component);
         }
 
-        private void AnythingMoved(MoveEvent args)
+        private void AnythingMoved(ref MoveEvent args)
         {
             AnythingMovedSubHandler(args.Sender.Transform);
         }
@@ -156,7 +146,7 @@ namespace Robust.Client.GameObjects
             QueueSpriteUpdate(component);
         }
 
-        private void SpriteParentChanged(EntityUid uid, SpriteComponent component, EntParentChangedMessage args)
+        private void SpriteParentChanged(EntityUid uid, SpriteComponent component, ref EntParentChangedMessage args)
         {
             QueueSpriteUpdate(component);
         }
@@ -189,7 +179,7 @@ namespace Robust.Client.GameObjects
             QueueLightUpdate(component);
         }
 
-        private void LightParentChanged(EntityUid uid, PointLightComponent component, EntParentChangedMessage args)
+        private void LightParentChanged(EntityUid uid, PointLightComponent component, ref EntParentChangedMessage args)
         {
             QueueLightUpdate(component);
         }
@@ -259,9 +249,8 @@ namespace Robust.Client.GameObjects
             EntityManager.GetEntity(_mapManager.GetGrid(gridId).GridEntityId).EnsureComponent<RenderingTreeComponent>();
         }
 
-        private RenderingTreeComponent? GetRenderTree(IEntity entity)
+        internal static RenderingTreeComponent? GetRenderTree(IEntity entity)
         {
-
             if (entity.Transform.MapID == MapId.Nullspace ||
                 entity.HasComponent<RenderingTreeComponent>()) return null;
 
@@ -278,6 +267,11 @@ namespace Robust.Client.GameObjects
             return null;
         }
 
+        private bool IsVisible(SpriteComponent component)
+        {
+            return component.Visible && !component.ContainerOccluded;
+        }
+
         public override void FrameUpdate(float frameTime)
         {
             _checkedChildren.Clear();
@@ -285,7 +279,7 @@ namespace Robust.Client.GameObjects
             foreach (var sprite in _spriteQueue)
             {
                 sprite.TreeUpdateQueued = false;
-                if (!sprite.Visible || sprite.ContainerOccluded)
+                if (!IsVisible(sprite))
                 {
                     ClearSprite(sprite);
                     continue;
@@ -302,8 +296,7 @@ namespace Robust.Client.GameObjects
                     continue;
                 }
 
-                var treePos = newMapTree?.Owner.Transform.WorldPosition ?? Vector2.Zero;
-                var aabb = RenderingTreeComponent.SpriteAabbFunc(sprite, worldPos).Translated(-treePos);
+                var aabb = RenderingTreeComponent.SpriteAabbFunc(sprite, worldPos);
 
                 // If we're on a new map then clear the old one.
                 if (oldMapTree != newMapTree)
@@ -348,7 +341,7 @@ namespace Robust.Client.GameObjects
                 }
 
                 var treePos = newMapTree?.Owner.Transform.WorldPosition ?? Vector2.Zero;
-                var aabb = RenderingTreeComponent.LightAabbFunc(light, worldPos).Translated(-treePos);
+                var aabb = RenderingTreeComponent.LightAabbFunc(light, worldPos);
 
                 // If we're on a new map then clear the old one.
                 if (oldMapTree != newMapTree)

Robust.Client/GameObjects/EntitySystems/SpriteSystem.cs

@@ -15,15 +15,14 @@ namespace Robust.Client.GameObjects
     {
         [Dependency] private readonly IEyeManager _eyeManager = default!;
         [Dependency] private readonly IMapManager _mapManager = default!;
+        [Dependency] private readonly RenderingTreeSystem _treeSystem = default!;
 
-        private RenderingTreeSystem _treeSystem = default!;
         private readonly Queue<SpriteComponent> _inertUpdateQueue = new();
 
         public override void Initialize()
         {
             base.Initialize();
 
-            _treeSystem = Get<RenderingTreeSystem>();
             SubscribeLocalEvent<SpriteUpdateInertEvent>(QueueUpdateInert);
         }
 

Robust.Client/Graphics/ClientEye/EyeManager.cs

@@ -111,10 +111,11 @@ namespace Robust.Client.Graphics
         public MapCoordinates ScreenToMap(ScreenCoordinates point)
         {
             var (pos, window) = point;
-            if (window != MainViewport.Window?.Id)
+
+            if (_uiManager.MouseGetControl(point) is not IViewportControl viewport)
                 return default;
 
-            return MainViewport.ScreenToMap(pos);
+            return viewport.ScreenToMap(pos);
         }
 
         /// <inheritdoc />

Robust.Client/Graphics/ClientEye/IEyeManager.cs

@@ -53,7 +53,7 @@ namespace Robust.Client.Graphics
         ScreenCoordinates CoordinatesToScreen(EntityCoordinates point);
 
         /// <summary>
-        /// Unprojects a point from UI screen space to world space using the current camera.
+        /// Unprojects a point from UI screen space to world space using the viewport under the screen coordinates.
         /// </summary>
         /// <remarks>
         /// The game exists on the 2D X/Y plane, so this function returns a point o the plane
@@ -64,7 +64,7 @@ namespace Robust.Client.Graphics
         MapCoordinates ScreenToMap(ScreenCoordinates point);
 
         /// <summary>
-        /// Unprojects a point from UI screen space to world space using the current camera.
+        /// Unprojects a point from UI screen space to world space using the main viewport.
         /// </summary>
         /// <remarks>
         /// The game exists on the 2D X/Y plane, so this function returns a point o the plane

Robust.Client/Graphics/Clyde/Clyde.Events.cs

@@ -62,7 +62,7 @@ namespace Robust.Client.Graphics.Clyde
                     TextEntered?.Invoke(args);
                     break;
                 case DEventWindowClosed(var reg, var args):
-                    reg.Closed?.Invoke(args);
+                    reg.RequestClosed?.Invoke(args);
                     CloseWindow?.Invoke(args);
 
                     if (reg.DisposeOnClose && !reg.IsMainWindow)
@@ -95,7 +95,7 @@ namespace Robust.Client.Graphics.Clyde
             _eventDispatchQueue.Enqueue(new DEventScroll(ev));
         }
 
-        private void SendCloseWindow(WindowReg windowReg, WindowClosedEventArgs ev)
+        private void SendCloseWindow(WindowReg windowReg, WindowRequestClosedEventArgs ev)
         {
             _eventDispatchQueue.Enqueue(new DEventWindowClosed(windowReg, ev));
         }
@@ -156,7 +156,7 @@ namespace Robust.Client.Graphics.Clyde
 
         private sealed record DEventScroll(MouseWheelEventArgs Args) : DEventBase;
 
-        private sealed record DEventWindowClosed(WindowReg Reg, WindowClosedEventArgs Args) : DEventBase;
+        private sealed record DEventWindowClosed(WindowReg Reg, WindowRequestClosedEventArgs Args) : DEventBase;
 
         private sealed record DEventWindowResized(WindowResizedEventArgs Args) : DEventBase;
 

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

@@ -4,6 +4,7 @@ using System.Collections.Generic;
 using OpenToolkit.Graphics.OpenGL4;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
+using Robust.Shared.Log;
 using Robust.Shared.Map;
 using Robust.Shared.Maths;
 
@@ -19,18 +20,17 @@ namespace Robust.Client.Graphics.Clyde
         private int _verticesPerChunk(IMapChunk chunk) => chunk.ChunkSize * chunk.ChunkSize * 4;
         private int _indicesPerChunk(IMapChunk chunk) => chunk.ChunkSize * chunk.ChunkSize * GetQuadBatchIndexCount();
 
-        private void _drawGrids(Box2 worldBounds)
+        private void _drawGrids(Viewport viewport, Box2 worldBounds, IEye eye)
         {
-            var mapId = _eyeManager.CurrentMap;
+            var mapId = eye.Position.MapId;
             if (!_mapManager.MapExists(mapId))
             {
-                // fall back to the default eye's map
-                _eyeManager.ClearCurrentEye();
-                mapId = _eyeManager.CurrentMap;
+                // fall back to nullspace map
+                mapId = MapId.Nullspace;
             }
 
             SetTexture(TextureUnit.Texture0, _tileDefinitionManager.TileTextureAtlas);
-            SetTexture(TextureUnit.Texture1, _lightingReady ? _currentViewport!.LightRenderTarget.Texture : _stockTextureWhite);
+            SetTexture(TextureUnit.Texture1, _lightingReady ? viewport.LightRenderTarget.Texture : _stockTextureWhite);
 
             var (gridProgram, _) = ActivateShaderInstance(_defaultShader.Handle);
             SetupGlobalUniformsImmediate(gridProgram, (ClydeTexture) _tileDefinitionManager.TileTextureAtlas);
@@ -53,14 +53,8 @@ namespace Robust.Client.Graphics.Clyde
                 var transform = compMan.GetComponent<ITransformComponent>(grid.GridEntityId);
                 gridProgram.SetUniform(UniIModelMatrix, transform.WorldMatrix);
 
-                foreach (var (_, chunk) in grid.GetMapChunks())
+                foreach (var chunk in grid.GetMapChunks(worldBounds))
                 {
-                    // Calc world bounds for chunk.
-                    if (!chunk.CalcWorldBounds().Intersects(in worldBounds))
-                    {
-                        continue;
-                    }
-
                     if (_isChunkDirty(grid, chunk))
                     {
                         _updateChunkMesh(grid, chunk);
@@ -210,11 +204,14 @@ namespace Robust.Client.Graphics.Clyde
 
         private void _updateOnGridCreated(MapId mapId, GridId gridId)
         {
+            Logger.DebugS("grid", $"Adding {gridId} to grid renderer");
             _mapChunkData.Add(gridId, new Dictionary<Vector2i, MapChunkData>());
         }
 
         private void _updateOnGridRemoved(MapId mapId, GridId gridId)
         {
+            Logger.DebugS("grid", $"Removing {gridId} from grid renderer");
+
             var data = _mapChunkData[gridId];
             foreach (var chunkDatum in data.Values)
             {

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

@@ -9,6 +9,7 @@ using Robust.Shared.Maths;
 using Robust.Shared.Utility;
 using OpenToolkit.Graphics.OpenGL4;
 using Robust.Client.UserInterface.CustomControls;
+using Robust.Shared;
 using Robust.Shared.Enums;
 
 namespace Robust.Client.Graphics.Clyde
@@ -201,9 +202,10 @@ namespace Robust.Client.Graphics.Clyde
         }
 
 
-        private void DrawEntities(Viewport viewport, Box2 worldBounds)
+        private void DrawEntities(Viewport viewport, Box2 worldBounds, IEye eye)
         {
-            if (_eyeManager.CurrentMap == MapId.Nullspace || !_mapManager.HasMapEntity(_eyeManager.CurrentMap))
+            var mapId = eye.Position.MapId;
+            if (mapId == MapId.Nullspace || !_mapManager.HasMapEntity(mapId))
             {
                 return;
             }
@@ -212,12 +214,7 @@ namespace Robust.Client.Graphics.Clyde
 
             var screenSize = viewport.Size;
 
-            // So we could calculate the correct size of the entities based on the contents of their sprite...
-            // Or we can just assume that no entity is larger than 10x10 and get a stupid easy check.
-            // TODO: Make this check more accurate.
-            var widerBounds = worldBounds.Enlarged(5);
-
-            ProcessSpriteEntities(_eyeManager.CurrentMap, widerBounds, _drawingSpriteList);
+            ProcessSpriteEntities(mapId, worldBounds, _drawingSpriteList);
 
             var worldOverlays = new List<Overlay>();
 
@@ -273,13 +270,15 @@ namespace Robust.Client.Graphics.Clyde
                     break;
                 }
 
+                var matrix = entry.worldMatrix;
+                var worldPosition = new Vector2(matrix.R0C2, matrix.R1C2);
 
                 RenderTexture? entityPostRenderTarget = null;
                 Vector2i roundedPos = default;
                 if (entry.sprite.PostShader != null)
                 {
                     // calculate world bounding box
-                    var spriteBB = entry.sprite.CalculateBoundingBox();
+                    var spriteBB = entry.sprite.CalculateBoundingBox(worldPosition);
                     var spriteLB = spriteBB.BottomLeft;
                     var spriteRT = spriteBB.TopRight;
 
@@ -291,6 +290,9 @@ namespace Robust.Client.Graphics.Clyde
                     // scale can be passed with PostShader as variable in future
                     var postShadeScale = 1.25f;
                     var screenSpriteSize = (Vector2i) ((screenRT - screenLB) * postShadeScale).Rounded();
+
+                    // Rotate the vector by the eye angle, otherwise the bounding box will be incorrect
+                    screenSpriteSize = (Vector2i) eye.Rotation.RotateVec(screenSpriteSize).Rounded();
                     screenSpriteSize.Y = -screenSpriteSize.Y;
 
                     // I'm not 100% sure why it works, but without it post-shader
@@ -323,9 +325,7 @@ namespace Robust.Client.Graphics.Clyde
                     }
                 }
 
-                var matrix = entry.worldMatrix;
-                var worldPosition = new Vector2(matrix.R0C2, matrix.R1C2);
-                entry.sprite.Render(_renderHandle.DrawingHandleWorld, in entry.worldRotation, in worldPosition);
+                entry.sprite.Render(_renderHandle.DrawingHandleWorld, eye.Rotation, in entry.worldRotation, in worldPosition);
 
                 if (entry.sprite.PostShader != null && entityPostRenderTarget != null)
                 {
@@ -370,7 +370,7 @@ namespace Robust.Client.Graphics.Clyde
             {
                 var bounds = worldBounds.Translated(-comp.Owner.Transform.WorldPosition);
 
-                comp.SpriteTree.QueryAabb(ref list, ((
+                comp.SpriteTree.QueryAabb(ref list, (
                     ref RefList<(SpriteComponent sprite, Matrix3 matrix, Angle worldRot, float yWorldPos)> state,
                     in SpriteComponent value) =>
                 {
@@ -381,17 +381,20 @@ namespace Robust.Client.Graphics.Clyde
                     entry.sprite = value;
                     entry.worldRot = transform.WorldRotation;
                     entry.matrix = transform.WorldMatrix;
-                    var worldPos = entry.matrix.Transform(transform.LocalPosition);
-                    entry.yWorldPos = worldPos.Y;
+                    var worldPos = new Vector2(entry.matrix.R0C2, entry.matrix.R1C2);
+                    // Didn't use the bounds from the query as that has to be re-calculated (and is probably more expensive than this).
+                    var bounds = value.CalculateBoundingBox(worldPos);
+                    entry.yWorldPos = worldPos.Y - bounds.Extents.Y;
                     return true;
 
-                }), bounds, true);
+                }, bounds);
             }
         }
 
         private void DrawSplash(IRenderHandle handle)
         {
-            var texture = _resourceCache.GetResource<TextureResource>("/Textures/Logo/logo.png").Texture;
+            var splashTex = _cfg.GetCVar(CVars.DisplaySplashLogo);
+            var texture = _resourceCache.GetResource<TextureResource>(splashTex).Texture;
 
             handle.DrawingHandleScreen.DrawTexture(texture, (ScreenSize - texture.Size) / 2);
         }
@@ -467,13 +470,13 @@ namespace Robust.Client.Graphics.Clyde
 
                     using (DebugGroup("Grids"))
                     {
-                        _drawGrids(worldBounds);
+                        _drawGrids(viewport, worldBounds, eye);
                     }
 
                     // We will also render worldspace overlays here so we can do them under / above entities as necessary
                     using (DebugGroup("Entities"))
                     {
-                        DrawEntities(viewport, worldBounds);
+                        DrawEntities(viewport, worldBounds, eye);
                     }
 
                     RenderOverlays(viewport, OverlaySpace.WorldSpaceBelowFOV, worldBounds);

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

@@ -5,6 +5,7 @@ using OpenToolkit.Graphics.OpenGL4;
 using Robust.Client.GameObjects;
 using Robust.Client.ResourceManagement;
 using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
 using Robust.Shared.Log;
 using Robust.Shared.Map;
 using Robust.Shared.Maths;
@@ -323,11 +324,17 @@ namespace Robust.Client.Graphics.Clyde
                 return;
             }
 
-            var map = eye.Position.MapId;
+            var mapId = eye.Position.MapId;
 
-            var (lights, count, expandedBounds) = GetLightsToRender(map, worldBounds);
+            // If this map has lighting disabled, return
+            if (!_mapManager.GetMapEntity(mapId).GetComponent<IMapComponent>().LightingEnabled)
+            {
+                return;
+            }
 
-            UpdateOcclusionGeometry(map, expandedBounds, eye.Position.Position);
+            var (lights, count, expandedBounds) = GetLightsToRender(mapId, worldBounds);
+
+            UpdateOcclusionGeometry(mapId, expandedBounds, eye.Position.Position);
 
             DrawFov(viewport, eye);
 
@@ -773,24 +780,13 @@ namespace Robust.Client.Graphics.Clyde
                 var ii = 0;
                 var imi = 0;
 
-                foreach (var gridId in _mapManager.FindGridIdsIntersecting(map, expandedBounds, true))
+                foreach (var comp in occluderSystem.GetOccluderTrees(map, expandedBounds))
                 {
-                    if (!occluderSystem.TryGetOccluderTreeForGrid(map, gridId, out var occluderTree)) continue;
+                    // TODO: I know this doesn't work with rotated grids but when I come back to these I'm adding tests
+                    // because rotation bugs are common.
+                    var treeBounds = expandedBounds.Translated(-comp.Owner.Transform.WorldPosition);
 
-                    Box2 gridBounds;
-
-                    if (gridId == GridId.Invalid)
-                    {
-                        gridBounds = expandedBounds;
-                    }
-                    else
-                    {
-                        // TODO: Ideally this would clamp to the outer border of what we can see
-                        var grid = _mapManager.GetGrid(gridId);
-                        gridBounds = expandedBounds.Translated(-grid.WorldPosition);
-                    }
-
-                    occluderTree.QueryAabb((in OccluderComponent sOccluder) =>
+                    comp.Tree.QueryAabb((in OccluderComponent sOccluder) =>
                     {
                         var occluder = (ClientOccluderComponent)sOccluder;
                         var transform = occluder.Owner.Transform;
@@ -919,7 +915,7 @@ namespace Robust.Client.Graphics.Clyde
                         ami += 4;
 
                         return true;
-                    }, gridBounds);
+                    }, treeBounds);
                 }
 
                 _occlusionDataLength = ii;

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

@@ -153,6 +153,7 @@ namespace Robust.Client.Graphics.Clyde
                 // Draw the entity.
                 sprite.Render(
                     DrawingHandleWorld,
+                    Angle.Zero,
                     overrideDirection == null
                         ? entity.Transform.WorldRotation
                         : Angle.Zero,

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

@@ -7,6 +7,7 @@ using OpenToolkit.Graphics.OpenGL4;
 using Robust.Client.GameObjects;
 using Robust.Client.Utility;
 using Robust.Shared;
+using Robust.Shared.GameObjects;
 using Robust.Shared.Maths;
 using Robust.Shared.Utility;
 using Color = Robust.Shared.Maths.Color;
@@ -1078,7 +1079,7 @@ namespace Robust.Client.Graphics.Clyde
                 var a = _drawList[x].Item1;
                 var b = _drawList[y].Item1;
 
-                var cmp = (a.DrawDepth).CompareTo(b.DrawDepth);
+                var cmp = a.DrawDepth.CompareTo(b.DrawDepth);
                 if (cmp != 0)
                 {
                     return cmp;
@@ -1091,7 +1092,7 @@ namespace Robust.Client.Graphics.Clyde
                     return cmp;
                 }
 
-                cmp = _drawList[x].Item4.CompareTo(_drawList[y].Item4);
+                cmp = _drawList[y].Item4.CompareTo(_drawList[x].Item4);
 
                 if (cmp != 0)
                 {

Robust.Client/Graphics/Clyde/Clyde.Textures.cs

@@ -1,7 +1,9 @@
 using System;
+using System.Buffers;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.IO;
+using System.Runtime.InteropServices;
 using System.Threading;
 using OpenToolkit.Graphics.OpenGL4;
 using Robust.Client.Utility;
@@ -153,6 +155,10 @@ namespace Robust.Client.Graphics.Clyde
             {
                 isActuallySrgb = loadParams.Srgb;
             }
+            else if (pixelType == typeof(Bgra32))
+            {
+                isActuallySrgb = loadParams.Srgb;
+            }
             else if (pixelType == typeof(A8))
             {
                 DebugTools.Assert(_hasGLTextureSwizzle);
@@ -258,6 +264,7 @@ namespace Robust.Client.Graphics.Clyde
                 // Note that if _hasGLSrgb is off, we import an sRGB texture as non-sRGB.
                 // Shaders are expected to compensate for this
                 Rgba32 => (srgb && _hasGLSrgb ? PIF.Srgb8Alpha8 : PIF.Rgba8, PF.Rgba, PT.UnsignedByte),
+                Bgra32 => (srgb && _hasGLSrgb ? PIF.Srgb8Alpha8 : PIF.Rgba8, PF.Bgra, PT.UnsignedByte),
                 A8 or L8 => (PIF.R8, PF.Red, PT.UnsignedByte),
                 _ => throw new NotSupportedException("Unsupported pixel type."),
             };
@@ -315,27 +322,80 @@ namespace Robust.Client.Graphics.Clyde
         private unsafe void SetSubImage<T>(
             ClydeTexture texture,
             Vector2i dstTl,
-            Image<T> srcImage,
+            Image<T> img,
             in UIBox2i srcBox)
             where T : unmanaged, IPixel<T>
         {
-            if (!_hasGLTextureSwizzle)
+            if (srcBox.Left < 0 ||
+                srcBox.Top < 0 ||
+                srcBox.Right > srcBox.Width ||
+                srcBox.Bottom > srcBox.Height)
             {
-                if (typeof(T) == typeof(A8))
-                {
-                    SetSubImage(texture, dstTl, ApplyA8Swizzle((Image<A8>) (object) srcImage), srcBox);
-                    return;
-                }
+                throw new ArgumentOutOfRangeException(nameof(srcBox), "Source rectangle out of bounds.");
+            }
 
-                if (typeof(T) == typeof(L8))
-                {
-                    SetSubImage(texture, dstTl, ApplyL8Swizzle((Image<L8>) (object) srcImage), srcBox);
-                    return;
-                }
+            var size = srcBox.Width * srcBox.Height;
+
+            T[]? pooled = null;
+            // C# won't let me use an if due to the stackalloc.
+            var copyBuffer = size < 16 * 16
+                ? stackalloc T[size]
+                : (pooled = ArrayPool<T>.Shared.Rent(size)).AsSpan(0, size);
+
+            var srcSpan = img.GetPixelSpan();
+            var w = img.Width;
+            FlipCopySubRegion(srcBox, w, srcSpan, copyBuffer);
+
+            SetSubImageImpl<T>(texture, dstTl, (srcBox.Width, srcBox.Height), copyBuffer);
+
+            if (pooled != null)
+                ArrayPool<T>.Shared.Return(pooled);
+        }
+
+        private unsafe void SetSubImage<T>(
+            ClydeTexture texture,
+            Vector2i dstTl,
+            Vector2i size,
+            ReadOnlySpan<T> buf)
+            where T : unmanaged, IPixel<T>
+        {
+            T[]? pooled = null;
+            // C# won't let me use an if due to the stackalloc.
+            var copyBuffer = buf.Length < 16 * 16
+                ? stackalloc T[buf.Length]
+                : (pooled = ArrayPool<T>.Shared.Rent(buf.Length)).AsSpan(0, buf.Length);
+
+            FlipCopy(buf, copyBuffer, size.X, size.Y);
+
+            SetSubImageImpl<T>(texture, dstTl, size, copyBuffer);
+
+            if (pooled != null)
+                ArrayPool<T>.Shared.Return(pooled);
+        }
+
+        private unsafe void SetSubImageImpl<T>(
+            ClydeTexture texture,
+            Vector2i dstTl,
+            Vector2i size,
+            ReadOnlySpan<T> buf)
+            where T : unmanaged, IPixel<T>
+        {
+            if (!_hasGLTextureSwizzle && typeof(T) == typeof(A8) && typeof(T) == typeof(L8))
+            {
+                var swizzleBuf = ArrayPool<Rgba32>.Shared.Rent(buf.Length);
+
+                var destSpan = swizzleBuf.AsSpan(0, buf.Length);
+                if (typeof(T) == typeof(A8))
+                    ApplyA8Swizzle(MemoryMarshal.Cast<T, A8>(buf), destSpan);
+                else if (typeof(T) == typeof(L8))
+                    ApplyL8Swizzle(MemoryMarshal.Cast<T, L8>(buf), destSpan);
+
+                SetSubImageImpl<Rgba32>(texture, dstTl, size, destSpan);
+                ArrayPool<Rgba32>.Shared.Return(swizzleBuf);
+                return;
             }
 
             var loaded = _loadedTextures[texture.TextureId];
-
             var pixType = GetTexturePixelType<T>();
 
             if (pixType != loaded.TexturePixelType)
@@ -346,11 +406,8 @@ namespace Robust.Client.Graphics.Clyde
                 throw new InvalidOperationException("Mismatching pixel type for texture.");
             }
 
-            if (loaded.Width < dstTl.X + srcBox.Width || loaded.Height < dstTl.Y + srcBox.Height)
-                throw new ArgumentOutOfRangeException(nameof(srcBox), "Destination rectangle out of bounds.");
-
-            if (srcBox.Left < 0 || srcBox.Top < 0 || srcBox.Right > srcImage.Width || srcBox.Bottom > srcImage.Height)
-                throw new ArgumentOutOfRangeException(nameof(srcBox), "Source rectangle out of bounds.");
+            if (loaded.Width < dstTl.X + size.X || loaded.Height < dstTl.Y + size.Y)
+                throw new ArgumentOutOfRangeException(nameof(size), "Destination rectangle out of bounds.");
 
             if (sizeof(T) != 4)
             {
@@ -364,24 +421,14 @@ namespace Robust.Client.Graphics.Clyde
             GL.BindTexture(TextureTarget.Texture2D, loaded.OpenGLObject.Handle);
             CheckGlError();
 
-            var size = srcBox.Width * srcBox.Height;
-
-            var copyBuffer = size < 16 * 16 ? stackalloc T[size] : new T[size];
-
-            for (var y = 0; y < srcBox.Height; y++)
-            for (var x = 0; x < srcBox.Width; x++)
+            fixed (T* aPtr = buf)
             {
-                copyBuffer[(srcBox.Height - y - 1) * srcBox.Width + x] = srcImage[x + srcBox.Left, srcBox.Top + y];
-            }
-
-            fixed (T* aPtr = copyBuffer)
-            {
-                var dstY = loaded.Height - dstTl.Y - srcBox.Height;
+                var dstY = loaded.Height - dstTl.Y - size.Y;
                 GL.TexSubImage2D(
                     TextureTarget.Texture2D,
                     0,
                     dstTl.X, dstY,
-                    srcBox.Width, srcBox.Height,
+                    size.X, size.Y,
                     pf, pt,
                     (IntPtr) aPtr);
                 CheckGlError();
@@ -398,7 +445,7 @@ namespace Robust.Client.Graphics.Clyde
         {
             return default(T) switch
             {
-                Rgba32 => TexturePixelType.Rgba32,
+                Rgba32 or Bgra32 => TexturePixelType.Rgba32,
                 L8 => TexturePixelType.L8,
                 A8 => TexturePixelType.A8,
                 _ => throw new NotSupportedException("Unsupported pixel type."),
@@ -452,17 +499,35 @@ namespace Robust.Client.Graphics.Clyde
             }
         }
 
+        private static void FlipCopySubRegion<T>(
+            UIBox2i srcBox,
+            int w,
+            ReadOnlySpan<T> srcSpan,
+            Span<T> copyBuffer)
+            where T : unmanaged, IPixel<T>
+        {
+            var subH = srcBox.Height;
+            var subW = srcBox.Width;
+
+            var dr = subH - 1;
+            for (var r = 0; r < subH; r++, dr--)
+            {
+                var si = r * w + srcBox.Left;
+                var di = dr * subW;
+                var srcRow = srcSpan[si..(si + subW)];
+                var dstRow = copyBuffer[di..(di + subW)];
+
+                srcRow.CopyTo(dstRow);
+            }
+        }
+
         private static Image<Rgba32> ApplyA8Swizzle(Image<A8> source)
         {
             var newImage = new Image<Rgba32>(source.Width, source.Height);
             var sourceSpan = source.GetPixelSpan();
             var destSpan = newImage.GetPixelSpan();
 
-            for (var i = 0; i < sourceSpan.Length; i++)
-            {
-                var px = sourceSpan[i].PackedValue;
-                destSpan[i] = new Rgba32(255, 255, 255, px);
-            }
+            ApplyA8Swizzle(sourceSpan, destSpan);
 
             return newImage;
         }
@@ -473,15 +538,28 @@ namespace Robust.Client.Graphics.Clyde
             var sourceSpan = source.GetPixelSpan();
             var destSpan = newImage.GetPixelSpan();
 
-            for (var i = 0; i < sourceSpan.Length; i++)
-            {
-                var px = sourceSpan[i].PackedValue;
-                destSpan[i] = new Rgba32(px, px, px, 255);
-            }
+            ApplyL8Swizzle(sourceSpan, destSpan);
 
             return newImage;
         }
 
+        private static void ApplyL8Swizzle(ReadOnlySpan<L8> src, Span<Rgba32> dst)
+        {
+            for (var i = 0; i < src.Length; i++)
+            {
+                var px = src[i].PackedValue;
+                dst[i] = new Rgba32(px, px, px, 255);
+            }
+        }
+
+        private static void ApplyA8Swizzle(ReadOnlySpan<A8> src, Span<Rgba32> dst)
+        {
+            for (var i = 0; i < src.Length; i++)
+            {
+                var px = src[i].PackedValue;
+                dst[i] = new Rgba32(255, 255, 255, px);
+            }
+        }
 
         private sealed class LoadedTexture
         {
@@ -525,6 +603,11 @@ namespace Robust.Client.Graphics.Clyde
                 _clyde.SetSubImage(this, topLeft, sourceImage, sourceRegion);
             }
 
+            public override void SetSubImage<T>(Vector2i topLeft, Vector2i size, ReadOnlySpan<T> buffer)
+            {
+                _clyde.SetSubImage(this, topLeft, size, buffer);
+            }
+
             protected override void Dispose(bool disposing)
             {
                 if (disposing)

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

@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Channels;
 using System.Threading.Tasks;
@@ -13,7 +12,7 @@ using Robust.Shared.Maths;
 using Robust.Shared.Utility;
 using SixLabors.ImageSharp;
 using SixLabors.ImageSharp.PixelFormats;
-using static Robust.Client.Utility.LiterallyJustMessageBox;
+using static Robust.Client.Utility.Win32;
 using FrameEventArgs = Robust.Shared.Timing.FrameEventArgs;
 
 namespace Robust.Client.Graphics.Clyde
@@ -26,6 +25,7 @@ namespace Robust.Client.Graphics.Clyde
         private IWindowingImpl? _windowing;
         private Renderer _chosenRenderer;
 
+        private ResourcePath? _windowIconPath;
         private Thread? _windowingThread;
         private bool _vSync;
         private WindowMode _windowMode;
@@ -39,7 +39,7 @@ namespace Robust.Client.Graphics.Clyde
         public event Action<KeyEventArgs>? KeyUp;
         public event Action<KeyEventArgs>? KeyDown;
         public event Action<MouseWheelEventArgs>? MouseWheel;
-        public event Action<WindowClosedEventArgs>? CloseWindow;
+        public event Action<WindowRequestClosedEventArgs>? CloseWindow;
         public event Action<WindowDestroyedEventArgs>? DestroyWindow;
         public event Action<WindowContentScaleEventArgs>? OnWindowScaleChanged;
         public event Action<WindowResizedEventArgs>? OnWindowResized;
@@ -87,6 +87,10 @@ namespace Robust.Client.Graphics.Clyde
 
         private bool InitWindowing()
         {
+            var iconPath = _cfg.GetCVar(CVars.DisplayWindowIconSet);
+            if (!string.IsNullOrWhiteSpace(iconPath))
+                _windowIconPath = new ResourcePath(iconPath);
+
             _windowingThread = Thread.CurrentThread;
 
             _windowing = new GlfwWindowingImpl(this);
@@ -164,13 +168,13 @@ namespace Robust.Client.Graphics.Clyde
 
         private IEnumerable<Image<Rgba32>> LoadWindowIcons()
         {
-            if (OperatingSystem.IsMacOS())
+            if (OperatingSystem.IsMacOS() || _windowIconPath == null)
             {
                 // Does nothing on macOS so don't bother.
                 yield break;
             }
 
-            foreach (var file in _resourceCache.ContentFindFiles("/Textures/Logo/icon"))
+            foreach (var file in _resourceCache.ContentFindFiles(_windowIconPath))
             {
                 if (file.Extension != "png")
                 {
@@ -210,11 +214,11 @@ namespace Robust.Client.Graphics.Clyde
             _windowing!.WindowRequestAttention(_windowing.MainWindow!);
         }
 
-        public async Task<IClydeWindow> CreateWindow(WindowCreateParameters parameters)
+        public IClydeWindow CreateWindow(WindowCreateParameters parameters)
         {
             DebugTools.AssertNotNull(_windowing);
 
-            return await _windowing!.WindowCreate(parameters);
+            return _windowing!.WindowCreate(parameters);
         }
 
         private void DoDestroyWindow(WindowReg reg)
@@ -222,8 +226,11 @@ namespace Robust.Client.Graphics.Clyde
             if (reg.IsMainWindow)
                 throw new InvalidOperationException("Cannot destroy main window.");
 
-            _windowing!.WindowDestroy(reg);
             reg.BlitDoneEvent?.Set();
+            _windowing!.WindowDestroy(reg);
+            var destroyed = new WindowDestroyedEventArgs(reg.Handle);
+            DestroyWindow?.Invoke(destroyed);
+            reg.Closed?.Invoke(destroyed);
         }
 
         public void ProcessInput(FrameEventArgs frameEventArgs)
@@ -396,10 +403,11 @@ namespace Robust.Client.Graphics.Clyde
             public bool IsMainWindow;
             public WindowHandle Handle = default!;
             public RenderTexture? RenderTexture;
-            public Action<WindowClosedEventArgs>? Closed;
+            public Action<WindowRequestClosedEventArgs>? RequestClosed;
+            public Action<WindowDestroyedEventArgs>? Closed;
         }
 
-        private sealed class WindowHandle : IClydeWindow
+        private sealed class WindowHandle : IClydeWindowInternal
         {
             // So funny story
             // When this class was a record, the C# compiler on .NET 5 stack overflowed
@@ -407,65 +415,73 @@ namespace Robust.Client.Graphics.Clyde
             // VERY funny.
 
             private readonly Clyde _clyde;
-            private readonly WindowReg _reg;
+            public readonly WindowReg Reg;
 
-            public bool IsDisposed => _reg.IsDisposed;
-            public WindowId Id => _reg.Id;
+            public bool IsDisposed => Reg.IsDisposed;
+            public WindowId Id => Reg.Id;
 
             public WindowHandle(Clyde clyde, WindowReg reg)
             {
                 _clyde = clyde;
-                _reg = reg;
+                Reg = reg;
             }
 
             public void Dispose()
             {
-                _clyde.DoDestroyWindow(_reg);
+                _clyde.DoDestroyWindow(Reg);
             }
 
-            public Vector2i Size => _reg.FramebufferSize;
+            public Vector2i Size => Reg.FramebufferSize;
 
             public IRenderTarget RenderTarget
             {
                 get
                 {
-                    if (_reg.IsMainWindow)
+                    if (Reg.IsMainWindow)
                     {
                         return _clyde._mainMainWindowRenderMainTarget;
                     }
 
-                    return _reg.RenderTexture!;
+                    return Reg.RenderTexture!;
                 }
             }
 
             public string Title
             {
-                get => _reg.Title;
-                set => _clyde._windowing!.WindowSetTitle(_reg, value);
+                get => Reg.Title;
+                set => _clyde._windowing!.WindowSetTitle(Reg, value);
             }
 
-            public bool IsFocused => _reg.IsFocused;
-            public bool IsMinimized => _reg.IsMinimized;
+            public bool IsFocused => Reg.IsFocused;
+            public bool IsMinimized => Reg.IsMinimized;
 
             public bool IsVisible
             {
-                get => _reg.IsVisible;
-                set => _clyde.SetWindowVisible(_reg, value);
+                get => Reg.IsVisible;
+                set => _clyde.SetWindowVisible(Reg, value);
             }
 
-            public Vector2 ContentScale => _reg.WindowScale;
+            public Vector2 ContentScale => Reg.WindowScale;
 
             public bool DisposeOnClose
             {
-                get => _reg.DisposeOnClose;
-                set => _reg.DisposeOnClose = value;
+                get => Reg.DisposeOnClose;
+                set => Reg.DisposeOnClose = value;
             }
 
-            public event Action<WindowClosedEventArgs> Closed
+            public event Action<WindowRequestClosedEventArgs> RequestClosed
             {
-                add => _reg.Closed += value;
-                remove => _reg.Closed -= value;
+                add => Reg.RequestClosed += value;
+                remove => Reg.RequestClosed -= value;
             }
+
+            public event Action<WindowDestroyedEventArgs>? Destroyed
+            {
+                add => Reg.Closed += value;
+                remove => Reg.Closed -= value;
+            }
+
+            public nint? WindowsHWnd => _clyde._windowing!.WindowGetWin32Window(Reg);
         }
 
         private sealed class MonitorHandle : IClydeMonitor

Robust.Client/Graphics/Clyde/Clyde.cs

@@ -24,6 +24,7 @@ namespace Robust.Client.Graphics.Clyde
     internal sealed partial class Clyde : IClydeInternal, IClydeAudio, IPostInjectInit
     {
         [Dependency] private readonly IClydeTileDefinitionManager _tileDefinitionManager = default!;
+        [Dependency] private readonly IEntityLookup _lookup = default!;
         [Dependency] private readonly IEyeManager _eyeManager = default!;
         [Dependency] private readonly ILightManager _lightManager = default!;
         [Dependency] private readonly ILogManager _logManager = default!;

Robust.Client/Graphics/Clyde/ClydeHeadless.cs

@@ -54,7 +54,7 @@ namespace Robust.Client.Graphics.Clyde
         public event Action<KeyEventArgs>? KeyUp { add { } remove { } }
         public event Action<KeyEventArgs>? KeyDown { add { } remove { } }
         public event Action<MouseWheelEventArgs>? MouseWheel { add { } remove { } }
-        public event Action<WindowClosedEventArgs>? CloseWindow { add { } remove { } }
+        public event Action<WindowRequestClosedEventArgs>? CloseWindow { add { } remove { } }
         public event Action<WindowDestroyedEventArgs>? DestroyWindow { add { } remove { } }
 
         public Texture GetStockTexture(ClydeStockTexture stockTexture)
@@ -210,7 +210,7 @@ namespace Robust.Client.Graphics.Clyde
             yield break;
         }
 
-        public Task<IClydeWindow> CreateWindow(WindowCreateParameters parameters)
+        public IClydeWindow CreateWindow(WindowCreateParameters parameters)
         {
             var window = new DummyWindow(CreateRenderTarget((123, 123), default))
             {
@@ -218,7 +218,7 @@ namespace Robust.Client.Graphics.Clyde
             };
             _windows.Add(window);
 
-            return Task.FromResult<IClydeWindow>(window);
+            return window;
         }
 
         public ClydeHandle LoadShader(ParsedShader shader, string? name = null)
@@ -396,6 +396,11 @@ namespace Robust.Client.Graphics.Clyde
             {
                 // Just do nothing on mutate.
             }
+
+            public override void SetSubImage<T>(Vector2i topLeft, Vector2i size, ReadOnlySpan<T> buffer)
+            {
+                // Just do nothing on mutate.
+            }
         }
 
         private sealed class DummyShaderInstance : ShaderInstance
@@ -605,7 +610,8 @@ namespace Robust.Client.Graphics.Clyde
             public bool IsVisible { get; set; } = true;
             public Vector2 ContentScale => Vector2.One;
             public bool DisposeOnClose { get; set; }
-            public event Action<WindowClosedEventArgs>? Closed { add { } remove { } }
+            public event Action<WindowRequestClosedEventArgs>? RequestClosed { add { } remove { } }
+            public event Action<WindowDestroyedEventArgs>? Destroyed;
 
             public void MaximizeOnMonitor(IClydeMonitor monitor)
             {
@@ -614,6 +620,8 @@ namespace Robust.Client.Graphics.Clyde
             public void Dispose()
             {
                 IsDisposed = true;
+
+                Destroyed?.Invoke(new WindowDestroyedEventArgs(this));
             }
         }
     }

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

@@ -131,10 +131,10 @@ namespace Robust.Client.Graphics.Clyde
 
             private void ProcessEventKey(EventKey ev)
             {
-                EmitKeyEvent(ConvertGlfwKey(ev.Key), ev.Action, ev.Mods);
+                EmitKeyEvent(ConvertGlfwKey(ev.Key), ev.Action, ev.Mods, ev.ScanCode);
             }
 
-            private void EmitKeyEvent(Keyboard.Key key, InputAction action, KeyModifiers mods)
+            private void EmitKeyEvent(Keyboard.Key key, InputAction action, KeyModifiers mods, int scanCode)
             {
                 var shift = (mods & KeyModifiers.Shift) != 0;
                 var alt = (mods & KeyModifiers.Alt) != 0;
@@ -144,7 +144,8 @@ namespace Robust.Client.Graphics.Clyde
                 var ev = new KeyEventArgs(
                     key,
                     action == InputAction.Repeat,
-                    alt, control, shift, system);
+                    alt, control, shift, system,
+                    scanCode);
 
                 switch (action)
                 {
@@ -162,7 +163,7 @@ namespace Robust.Client.Graphics.Clyde
 
             private void ProcessEventMouseButton(EventMouseButton ev)
             {
-                EmitKeyEvent(Mouse.MouseButtonToKey(ConvertGlfwButton(ev.Button)), ev.Action, ev.Mods);
+                EmitKeyEvent(Mouse.MouseButtonToKey(ConvertGlfwButton(ev.Button)), ev.Action, ev.Mods, default);
             }
 
             private void ProcessEventScroll(EventScroll ev)
@@ -183,7 +184,7 @@ namespace Robust.Client.Graphics.Clyde
                 if (windowReg == null)
                     return;
 
-                _clyde.SendCloseWindow(windowReg, new WindowClosedEventArgs(windowReg.Handle));
+                _clyde.SendCloseWindow(windowReg, new WindowRequestClosedEventArgs(windowReg.Handle));
             }
 
             private void ProcessEventWindowSize(EventWindowSize ev)

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

@@ -207,6 +207,7 @@ namespace Robust.Client.Graphics.Clyde
                 Renderer Renderer,
                 WindowCreateParameters Parameters,
                 nint ShareWindow,
+                nint OwnerWindow,
                 TaskCompletionSource<GlfwWindowCreateResult> Tcs
             ) : CmdBase;
 

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

@@ -3,7 +3,6 @@ using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Runtime.InteropServices;
-using System.Runtime.Loader;
 using System.Threading.Tasks;
 using OpenToolkit;
 using OpenToolkit.Graphics.OpenGL4;
@@ -22,8 +21,7 @@ namespace Robust.Client.Graphics.Clyde
 {
     internal partial class Clyde
     {
-        // Wait for it.
-        private sealed partial class GlfwWindowingImpl
+        private unsafe sealed partial class GlfwWindowingImpl
         {
             private readonly List<GlfwWindowReg> _windows = new();
 
@@ -36,45 +34,31 @@ namespace Robust.Client.Graphics.Clyde
             private int _nextWindowId = 1;
             private static bool _eglLoaded;
 
-            public async Task<WindowHandle> WindowCreate(WindowCreateParameters parameters)
+            public WindowHandle WindowCreate(WindowCreateParameters parameters)
             {
-                // tfw await not allowed in unsafe contexts
-
-                // GL APIs don't take kindly to making a new window without unbinding the main context. Great.
-                // Leaving code for async path in, in case it works on like GLX.
-                var unbindContextAndBlock = true;
-
                 DebugTools.AssertNotNull(_mainWindow);
 
-                Task<GlfwWindowCreateResult> task;
-                unsafe
-                {
-                    if (unbindContextAndBlock)
-                        GLFW.MakeContextCurrent(null);
+                GLFW.MakeContextCurrent(null);
 
-                    task = SharedWindowCreate(
-                        _clyde._chosenRenderer,
-                        parameters,
-                        _mainWindow!.GlfwWindow);
+                Window* ownerPtr = null;
+                if (parameters.Owner != null)
+                {
+                    var ownerReg = (GlfwWindowReg) ((WindowHandle)parameters.Owner).Reg;
+                    ownerPtr = ownerReg.GlfwWindow;
                 }
 
-                if (unbindContextAndBlock)
-                {
-                    unsafe
-                    {
-                        // Block the main thread (to avoid stuff like texture uploads being problematic).
-                        WaitWindowCreate(task);
+                var task = SharedWindowCreate(
+                    _clyde._chosenRenderer,
+                    parameters,
+                    _mainWindow!.GlfwWindow,
+                    ownerPtr);
 
-                        if (unbindContextAndBlock)
-                            GLFW.MakeContextCurrent(_mainWindow.GlfwWindow);
-                    }
-                }
-                else
-                {
-                    await task;
-                }
+                // Block the main thread (to avoid stuff like texture uploads being problematic).
+                WaitWindowCreate(task);
 
-                var (reg, error) = await task;
+                GLFW.MakeContextCurrent(_mainWindow.GlfwWindow);
+
+                var (reg, error) = task.Result;
 
                 if (reg == null)
                 {
@@ -85,18 +69,11 @@ namespace Robust.Client.Graphics.Clyde
                 _clyde.CreateWindowRenderTexture(reg);
                 _clyde.InitWindowBlitThread(reg);
 
-                unsafe
-                {
-                    GLFW.MakeContextCurrent(_mainWindow.GlfwWindow);
-                }
+                GLFW.MakeContextCurrent(_mainWindow.GlfwWindow);
 
                 return reg.Handle;
             }
-        }
 
-        // Yes, you read that right.
-        private sealed unsafe partial class GlfwWindowingImpl
-        {
             public bool TryInitMainWindow(Renderer renderer, [NotNullWhen(false)] out string? error)
             {
                 var width = _cfg.GetCVar(CVars.DisplayWidth);
@@ -123,7 +100,7 @@ namespace Robust.Client.Graphics.Clyde
                     Fullscreen = fullscreen
                 };
 
-                var windowTask = SharedWindowCreate(renderer, parameters, null);
+                var windowTask = SharedWindowCreate(renderer, parameters, null, null);
                 WaitWindowCreate(windowTask);
 
                 var (reg, err) = windowTask.Result;
@@ -165,14 +142,30 @@ namespace Robust.Client.Graphics.Clyde
             private Task<GlfwWindowCreateResult> SharedWindowCreate(
                 Renderer renderer,
                 WindowCreateParameters parameters,
-                Window* share)
+                Window* share, Window* owner)
             {
+                //
+                // IF YOU'RE WONDERING WHY THIS IS TASK-BASED:
+                // I originally wanted this to be async so we could avoid blocking the main thread
+                // while the OS takes its stupid 100~ms just to initialize a fucking GL context.
+                // This doesn't *work* because
+                // we have to release the GL context while the shared context is being created.
+                // (at least on WGL, I didn't test other platforms and I don't care to.)
+                // Not worth it to avoid a main thread blockage by allowing Clyde to temporarily release the GL context,
+                // because rendering would be locked up *anyways*.
+                //
+                // Basically what I'm saying is that everything about OpenGL is a fucking mistake
+                // and I should get on either Veldrid or Vulkan some time.
+                // Probably Veldrid tbh.
+                //
+
                 // Yes we ping-pong this TCS through the window thread and back, deal with it.
                 var tcs = new TaskCompletionSource<GlfwWindowCreateResult>();
                 SendCmd(new CmdWinCreate(
                     renderer,
                     parameters,
                     (nint) share,
+                    (nint) owner,
                     tcs));
 
                 return tcs.Task;
@@ -194,9 +187,9 @@ namespace Robust.Client.Graphics.Clyde
 
             private void WinThreadWinCreate(CmdWinCreate cmd)
             {
-                var (renderer, parameters, share, tcs) = cmd;
+                var (renderer, parameters, share, owner, tcs) = cmd;
 
-                var window = CreateGlfwWindowForRenderer(renderer, parameters, (Window*) share);
+                var window = CreateGlfwWindowForRenderer(renderer, parameters, (Window*) share, (Window*) owner);
 
                 if (window == null)
                 {
@@ -418,6 +411,22 @@ namespace Robust.Client.Graphics.Clyde
                 }
             }
 
+            public nint? WindowGetWin32Window(WindowReg window)
+            {
+                if (!OperatingSystem.IsWindows())
+                    return null;
+
+                var reg = (GlfwWindowReg) window;
+                try
+                {
+                    return GLFW.GetWin32Window(reg.GlfwWindow);
+                }
+                catch (EntryPointNotFoundException)
+                {
+                    return null;
+                }
+            }
+
             public void WindowDestroy(WindowReg window)
             {
                 var reg = (GlfwWindowReg) window;
@@ -430,14 +439,13 @@ namespace Robust.Client.Graphics.Clyde
 
                 _windows.Remove(reg);
                 _clyde._windowHandles.Remove(reg.Handle);
-
-                _clyde.DestroyWindow?.Invoke(new WindowDestroyedEventArgs(window.Handle));
             }
 
             private Window* CreateGlfwWindowForRenderer(
                 Renderer r,
                 WindowCreateParameters parameters,
-                Window* contextShare)
+                Window* contextShare,
+                Window* ownerWindow)
             {
 #if DEBUG
                 GLFW.WindowHint(WindowHintBool.OpenGLDebugContext, true);
@@ -445,6 +453,8 @@ namespace Robust.Client.Graphics.Clyde
                 GLFW.WindowHint(WindowHintString.X11ClassName, "SS14");
                 GLFW.WindowHint(WindowHintString.X11InstanceName, "SS14");
 
+                GLFW.WindowHint(WindowHintBool.ScaleToMonitor, true);
+
                 if (r == Renderer.OpenGL33)
                 {
                     GLFW.WindowHint(WindowHintInt.ContextVersionMajor, 3);
@@ -519,13 +529,63 @@ namespace Robust.Client.Graphics.Clyde
                     GLFW.MaximizeWindow(window);
                 }
 
+                if ((parameters.Styles & OSWindowStyles.NoTitleOptions) != 0)
+                {
+                    if (OperatingSystem.IsWindows())
+                    {
+                        var hWnd = (void*) GLFW.GetWin32Window(window);
+                        DebugTools.Assert(hWnd != null);
+
+                        Win32.SetWindowLongPtrW(
+                            hWnd,
+                            Win32.GWL_STYLE,
+                            // Cast to long here to work around a bug in rider with nint bitwise operators.
+                            (nint)((long)Win32.GetWindowLongPtrW(hWnd, Win32.GWL_STYLE) & ~Win32.WS_SYSMENU));
+                    }
+                    else
+                    {
+                        _sawmill.Warning("OSWindowStyles.NoTitleOptions not implemented on this platform");
+                    }
+                }
+
+                if (ownerWindow != null)
+                {
+                    if (OperatingSystem.IsWindows())
+                    {
+                        var hWnd = (void*) GLFW.GetWin32Window(window);
+                        var ownerHWnd = GLFW.GetWin32Window(ownerWindow);
+                        DebugTools.Assert(hWnd != null);
+
+                        Win32.SetWindowLongPtrW(
+                            hWnd,
+                            Win32.GWLP_HWNDPARENT,
+                            ownerHWnd);
+                    }
+                    else
+                    {
+                        _sawmill.Warning("owner windows not implemented on this platform");
+                    }
+
+
+                    if (parameters.StartupLocation == WindowStartupLocation.CenterOwner)
+                    {
+                        // TODO: Maybe include window frames in size calculations here?
+                        // Figure out frame sizes of both windows.
+                        GLFW.GetWindowPos(ownerWindow, out var ownerX, out var ownerY);
+                        GLFW.GetWindowSize(ownerWindow, out var ownerW, out var ownerH);
+
+                        // Re-fetch this in case DPI scaling is changing it I guess.
+                        GLFW.GetWindowSize(window, out var thisW, out var thisH);
+
+                        GLFW.SetWindowPos(window, ownerX + (ownerW - thisW) / 2, ownerY + (ownerH - thisH) / 2);
+                    }
+                }
+
                 if (parameters.Visible)
                 {
                     GLFW.ShowWindow(window);
                 }
 
-
-
                 return window;
             }
 

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

@@ -38,7 +38,8 @@ namespace Robust.Client.Graphics.Clyde
             void WindowRequestAttention(WindowReg window);
             void WindowSwapBuffers(WindowReg window);
             uint? WindowGetX11Id(WindowReg window);
-            Task<WindowHandle> WindowCreate(WindowCreateParameters parameters);
+            nint? WindowGetWin32Window(WindowReg window);
+            WindowHandle WindowCreate(WindowCreateParameters parameters);
             void WindowDestroy(WindowReg reg);
 
             string KeyGetName(Keyboard.Key key);

Robust.Client/Graphics/IClyde.cs

@@ -130,6 +130,6 @@ namespace Robust.Client.Graphics
 
         IEnumerable<IClydeMonitor> EnumerateMonitors();
 
-        Task<IClydeWindow> CreateWindow(WindowCreateParameters parameters);
+        IClydeWindow CreateWindow(WindowCreateParameters parameters);
     }
 }

Robust.Client/Graphics/IClydeInternal.cs

@@ -28,7 +28,7 @@ namespace Robust.Client.Graphics
         event Action<KeyEventArgs> KeyUp;
         event Action<KeyEventArgs> KeyDown;
         event Action<MouseWheelEventArgs> MouseWheel;
-        event Action<WindowClosedEventArgs> CloseWindow;
+        event Action<WindowRequestClosedEventArgs> CloseWindow;
         event Action<WindowDestroyedEventArgs> DestroyWindow;
 
         ClydeHandle LoadShader(ParsedShader shader, string? name = null);

Robust.Client/Graphics/IClydeWindow.cs

@@ -28,6 +28,17 @@ namespace Robust.Client.Graphics
         ///     Fired when the user tries to close the window. Note that if <see cref="DisposeOnClose"/> is not true,
         ///     this is merely a request and the user pressing the close button does nothing.
         /// </summary>
-        event Action<WindowClosedEventArgs> Closed;
+        event Action<WindowRequestClosedEventArgs> RequestClosed;
+
+        /// <summary>
+        /// Raised when the window has been definitively closed.
+        /// This means the window must not be used anymore (it is disposed).
+        /// </summary>
+        event Action<WindowDestroyedEventArgs> Destroyed;
+    }
+
+    public interface IClydeWindowInternal : IClydeWindow
+    {
+        nint? WindowsHWnd { get; }
     }
 }

Robust.Client/Graphics/OwnedTexture.cs

@@ -42,6 +42,9 @@ namespace Robust.Client.Graphics
             SetSubImage(topLeft, sourceImage, UIBox2i.FromDimensions(0, 0, sourceImage.Width, sourceImage.Height));
         }
 
+        public abstract void SetSubImage<T>(Vector2i topLeft, Vector2i size, ReadOnlySpan<T> buffer)
+            where T : unmanaged, IPixel<T>;
+
         public void Dispose()
         {
             Dispose(true);

Robust.Client/Graphics/WindowClosedEventArgs.cs

@@ -1,14 +0,0 @@
-using System;
-
-namespace Robust.Client.Graphics
-{
-    public class WindowClosedEventArgs : EventArgs
-    {
-        public IClydeWindow Window { get; }
-
-        public WindowClosedEventArgs(IClydeWindow window)
-        {
-            Window = window;
-        }
-    }
-}

Robust.Client/Graphics/WindowContentScaleEventArgs.cs

@@ -1,8 +1,6 @@
-using System;
-
-namespace Robust.Client.Graphics
+namespace Robust.Client.Graphics
 {
-    public sealed class WindowContentScaleEventArgs : EventArgs
+    public readonly struct WindowContentScaleEventArgs
     {
         public WindowContentScaleEventArgs(IClydeWindow window)
         {

Robust.Client/Graphics/WindowCreateParameters.cs

@@ -1,4 +1,6 @@
-namespace Robust.Client.Graphics
+using System;
+
+namespace Robust.Client.Graphics
 {
     public sealed class WindowCreateParameters
     {
@@ -9,5 +11,54 @@
         public bool Visible = true;
         public IClydeMonitor? Monitor;
         public bool Fullscreen;
+
+        /// <summary>
+        /// The window that will "own" this window.
+        /// Owned windows always appear on top of their owners and have some other misc behavior depending on the OS.
+        /// </summary>
+        public IClydeWindow? Owner;
+
+        /// <summary>
+        /// Controls where a window is initially placed when created.
+        /// </summary>
+        public WindowStartupLocation StartupLocation;
+
+        /// <summary>
+        /// Specifies window styling options for the created window.
+        /// </summary>
+        public OSWindowStyles Styles;
+    }
+
+    /// <summary>
+    /// Controls where a window is initially placed when created.
+    /// </summary>
+    public enum WindowStartupLocation : byte
+    {
+        /// <summary>
+        /// The window position is automatically picked by the windowing system.
+        /// </summary>
+        Manual,
+
+        /// <summary>
+        /// The window is positioned at the center of the <see cref="WindowCreateParameters.Owner"/> window.
+        /// </summary>
+        CenterOwner,
+    }
+
+    /// <summary>
+    /// Specifies window styling options for an OS window.
+    /// </summary>
+    [Flags]
+    public enum OSWindowStyles
+    {
+        /// <summary>
+        /// No special styles set.
+        /// </summary>
+        None = 0,
+
+        /// <summary>
+        /// Hide title buttons such as close and minimize.
+        /// </summary>
+        NoTitleOptions = 1 << 0
     }
 }

Robust.Client/Graphics/WindowDestroyedEventArgs.cs

@@ -1,8 +1,6 @@
-using System;
-
-namespace Robust.Client.Graphics
+namespace Robust.Client.Graphics
 {
-    public class WindowDestroyedEventArgs : EventArgs
+    public readonly struct WindowDestroyedEventArgs
     {
         public IClydeWindow Window { get; }
 

Robust.Client/Graphics/WindowFocusedEventArgs.cs

@@ -1,8 +1,6 @@
-using System;
-
-namespace Robust.Client.Graphics
+namespace Robust.Client.Graphics
 {
-    public class WindowFocusedEventArgs : EventArgs
+    public readonly struct WindowFocusedEventArgs
     {
         public WindowFocusedEventArgs(bool focused, IClydeWindow window)
         {

Robust.Client/Graphics/WindowRequestClosedEventArgs.cs

@@ -0,0 +1,12 @@
+namespace Robust.Client.Graphics
+{
+    public readonly struct WindowRequestClosedEventArgs
+    {
+        public IClydeWindow Window { get; }
+
+        public WindowRequestClosedEventArgs(IClydeWindow window)
+        {
+            Window = window;
+        }
+    }
+}

Robust.Client/Graphics/WindowResizedEventArgs.cs

@@ -1,9 +1,8 @@
-using System;
 using Robust.Shared.Maths;
 
 namespace Robust.Client.Graphics
 {
-    public class WindowResizedEventArgs : EventArgs
+    public readonly struct WindowResizedEventArgs
     {
         public WindowResizedEventArgs(Vector2i oldSize, Vector2i newSize, IClydeWindow window)
         {

Robust.Client/Input/Events.cs

@@ -76,11 +76,18 @@ namespace Robust.Client.Input
         /// </summary>
         public bool IsRepeat { get; }
 
-        public KeyEventArgs(Keyboard.Key key, bool repeat, bool alt, bool control, bool shift, bool system)
+        public int ScanCode { get; }
+
+        public KeyEventArgs(
+            Keyboard.Key key,
+            bool repeat,
+            bool alt, bool control, bool shift, bool system,
+            int scanCode)
             : base(alt, control, shift, system)
         {
             Key = key;
             IsRepeat = repeat;
+            ScanCode = scanCode;
         }
     }
 

Robust.Client/Input/IInputManager.cs

@@ -129,5 +129,7 @@ namespace Robust.Client.Input
         void ResetAllBindings();
 
         bool IsKeyFunctionModified(BoundKeyFunction function);
+
+        bool IsKeyDown(Keyboard.Key key);
     }
 }

Robust.Client/Input/InputManager.cs

@@ -16,6 +16,7 @@ using Robust.Shared.IoC;
 using Robust.Shared.Localization;
 using Robust.Shared.Log;
 using Robust.Shared.Map;
+using Robust.Shared.Maths;
 using Robust.Shared.Reflection;
 using Robust.Shared.Serialization;
 using Robust.Shared.Serialization.Manager;
@@ -41,7 +42,7 @@ namespace Robust.Client.Input
 
         [Dependency] private readonly IResourceManager _resourceMan = default!;
         [Dependency] private readonly IReflectionManager _reflectionManager = default!;
-        [Dependency] private readonly IUserInterfaceManagerInternal _userInterfaceManagerInternal = default!;
+        [Dependency] private readonly IUserInterfaceManagerInternal _uiMgr = default!;
 
         private bool _currentlyFindingViewport;
 
@@ -248,7 +249,15 @@ namespace Robust.Client.Input
             var uiOnly = false;
             if (hasCanFocus)
             {
-                uiOnly = _userInterfaceManagerInternal.HandleCanFocusDown(MouseScreenPosition);
+                uiOnly = _uiMgr.HandleCanFocusDown(MouseScreenPosition, out _);
+            }
+
+            if (_uiMgr.KeyboardFocused is IRawInputControl rawInput)
+            {
+                var block = RaiseRawKeyInput(args, rawInput, args.IsRepeat ? RawKeyAction.Repeat : RawKeyAction.Down);
+
+                if (block)
+                    return;
             }
 
             foreach (var binding in bindsDown)
@@ -260,6 +269,21 @@ namespace Robust.Client.Input
             }
         }
 
+        private bool RaiseRawKeyInput(KeyEventArgs args, IRawInputControl rawInput, RawKeyAction action)
+        {
+            DebugTools.AssertNotNull(_uiMgr.KeyboardFocused);
+
+            var mousePos = _uiMgr.CalcRelativeMousePositionFor(_uiMgr.KeyboardFocused!, _uiMgr.MousePositionScaled);
+            var keyEvent = new GuiRawKeyEvent(
+                args.Key,
+                args.ScanCode,
+                action,
+                (Vector2i) (mousePos ?? Vector2.Zero));
+
+            var block = rawInput.RawKeyEvent(keyEvent);
+            return block;
+        }
+
         /// <inheritdoc />
         public void KeyUp(KeyEventArgs args)
         {
@@ -289,8 +313,11 @@ namespace Robust.Client.Input
 
             if (hasCanFocus)
             {
-                _userInterfaceManagerInternal.HandleCanFocusUp();
+                _uiMgr.HandleCanFocusUp();
             }
+
+            if (_uiMgr.KeyboardFocused is IRawInputControl rawInput)
+                RaiseRawKeyInput(args, rawInput, RawKeyAction.Up);
         }
 
         private bool DownBind(KeyBinding binding, bool uiOnly, bool isRepeat)
@@ -607,6 +634,11 @@ namespace Robust.Client.Input
             return _modifiedKeyFunctions.Contains(function);
         }
 
+        public bool IsKeyDown(Key key)
+        {
+            return _keysPressed[(int) key];
+        }
+
         /// <inheritdoc />
         public bool TryGetKeyBinding(BoundKeyFunction function, [NotNullWhen(true)] out IKeyBinding? binding)
         {

Robust.Client/Log/DebugConsoleLogHandler.cs

@@ -20,6 +20,9 @@ namespace Robust.Client.Log
 
         public void Log(string sawmillName, LogEvent message)
         {
+            if (sawmillName == "CON")
+                return;
+
             var formatted = new FormattedMessage(8);
             var robustLevel = message.Level.ToRobust();
             formatted.PushColor(Color.DarkGray);

Robust.Client/Map/ClientMapManager.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using Robust.Shared.GameObjects;
 using Robust.Shared.GameStates;
+using Robust.Shared.Log;
 using Robust.Shared.Map;
 using Robust.Shared.Maths;
 using Robust.Shared.Utility;
@@ -134,15 +135,24 @@ namespace Robust.Client.Map
                                 }
                             }
                         }
-
-                        chunk.SuppressCollisionRegeneration = false;
-                        chunk.RegenerateCollision();
                     }
 
                     if (modified.Count != 0)
                     {
                         InvokeGridChanged(this, new GridChangedEventArgs(grid, modified));
                     }
+
+                    foreach (var chunkData in gridDatum.ChunkData)
+                    {
+                        var chunk = grid.GetChunk(chunkData.Index);
+                        chunk.SuppressCollisionRegeneration = false;
+                        chunk.RegenerateCollision();
+                    }
+
+                    foreach (var chunkData in gridDatum.DeletedChunkData)
+                    {
+                        grid.RemoveChunk(chunkData.Index);
+                    }
                 }
 
                 SuppressOnTileChanged = false;

Robust.Client/Map/ClydeTileDefinitionManager.cs

@@ -8,6 +8,7 @@ using Robust.Client.Utility;
 using Robust.Shared.IoC;
 using Robust.Shared.Map;
 using Robust.Shared.Maths;
+using Robust.Shared.Utility;
 using SixLabors.ImageSharp;
 using SixLabors.ImageSharp.PixelFormats;
 
@@ -62,7 +63,7 @@ namespace Robust.Client.Map
                 var row = i / dimensionX;
 
                 Image<Rgba32> image;
-                using (var stream = _resourceCache.ContentFileRead(Path.Join(def.Path, $"{def.SpriteName}.png")))
+                using (var stream = _resourceCache.ContentFileRead(new ResourcePath(def.Path) / $"{def.SpriteName}.png"))
                 {
                     image = Image.Load<Rgba32>(stream);
                 }

Robust.Client/Physics/BroadPhaseSystem.cs

@@ -1,8 +1,8 @@
-using Robust.Shared.Physics.Broadphase;
+using Robust.Shared.Physics;
 
 namespace Robust.Client.Physics
 {
-    internal sealed class BroadPhaseSystem : SharedBroadPhaseSystem
+    internal sealed class BroadPhaseSystem : SharedBroadphaseSystem
     {
         public override void Initialize()
         {

Robust.Client/Physics/PhysicsMapComponent.cs

@@ -0,0 +1,57 @@
+using System.Collections.Generic;
+using Robust.Shared;
+using Robust.Shared.Configuration;
+using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.Physics.Dynamics;
+
+namespace Robust.Client.Physics
+{
+    [RegisterComponent]
+    [ComponentReference(typeof(SharedPhysicsMapComponent))]
+    public sealed class PhysicsMapComponent : SharedPhysicsMapComponent
+    {
+        private float _timeToSleep;
+
+        protected override void Initialize()
+        {
+            base.Initialize();
+            var configManager = IoCManager.Resolve<IConfigurationManager>();
+            configManager.OnValueChanged(CVars.TimeToSleep, SetTimeToSleep);
+        }
+
+        protected override void OnRemove()
+        {
+            base.OnRemove();
+            var configManager = IoCManager.Resolve<IConfigurationManager>();
+            configManager.UnsubValueChanged(CVars.TimeToSleep, SetTimeToSleep);
+        }
+
+        private void SetTimeToSleep(float value) => _timeToSleep = value;
+
+        protected override void Cleanup(float frameTime)
+        {
+            var toRemove = new List<PhysicsComponent>();
+
+            // Because we're not predicting 99% of bodies its sleep timer never gets incremented so we'll just do it ourselves.
+            // (and serializing it over the network isn't necessary?)
+            // This is a client-only problem.
+            foreach (var body in AwakeBodies)
+            {
+                if (body.Island || body.LinearVelocity.Length > 0f || body.AngularVelocity != 0f) continue;
+                body.SleepTime += frameTime;
+                if (body.SleepTime > _timeToSleep)
+                {
+                    toRemove.Add(body);
+                }
+            }
+
+            foreach (var body in toRemove)
+            {
+                body.Awake = false;
+            }
+
+            base.Cleanup(frameTime);
+        }
+    }
+}

Robust.Client/Physics/PhysicsSystem.cs

@@ -2,6 +2,7 @@
 using JetBrains.Annotations;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
+using Robust.Shared.Map;
 using Robust.Shared.Timing;
 
 namespace Robust.Client.Physics
@@ -16,8 +17,7 @@ namespace Robust.Client.Physics
         public override void Update(float frameTime)
         {
             _lastRem = _gameTiming.CurTime;
-
-            SimulateWorld(frameTime, !_gameTiming.InSimulation || !_gameTiming.IsFirstTimePredicted);
+            SimulateWorld(frameTime, _gameTiming.InPrediction);
         }
 
         public override void FrameUpdate(float frameTime)
@@ -31,5 +31,11 @@ namespace Robust.Client.Physics
             _lastRem = _gameTiming.TickRemainder;
             SimulateWorld((float) diff.TotalSeconds, true);
         }
+
+        protected override void HandleMapCreated(object? sender, MapEventArgs eventArgs)
+        {
+            if (eventArgs.Map == MapId.Nullspace) return;
+            MapManager.GetMapEntity(eventArgs.Map).AddComponent<PhysicsMapComponent>();
+        }
     }
 }

Robust.Client/Placement/Modes/AlignTileAny.cs

@@ -11,7 +11,8 @@ namespace Robust.Client.Placement.Modes
 
         public override void AlignPlacementMode(ScreenCoordinates mouseScreen)
         {
-            const float SearchBoxSize = 1.5f; // size of search box in meters
+            // Go over diagonal size so when placing in a line it doesn't stop snapping.
+            const float SearchBoxSize = 2f; // size of search box in meters
 
             MouseCoords = ScreenToCursorGrid(mouseScreen).AlignWithClosestGridTile(SearchBoxSize, pManager.EntityManager, pManager.MapManager);
 

Robust.Client/Placement/PlacementManager.cs

@@ -504,8 +504,8 @@ namespace Robust.Client.Placement
                     coordinates = new EntityCoordinates();
                     return false;
                 }
-                coordinates = EntityCoordinates.FromMap(ent.EntityManager, MapManager,
-                    eyeManager.ScreenToMap(_inputManager.MouseScreenPosition));
+                coordinates = EntityCoordinates.FromMap(MapManager,
+                                                        eyeManager.ScreenToMap(_inputManager.MouseScreenPosition));
                 return true;
             }
         }