SDL3 (#5583)

* Start converting SDL2 backend to SDL3.

Game starts, but a lot of stuff is broken. Oh well.

* Fix text input

SDL3 changed the API somewhat, for the better. Changes all over UI/Clyde/SDL3 layer.

* Fix mouse buttons being broken

* Remove records from SDL3 WSI

The fact that this shaved 2-3% off Robust.Client.dll is mindboggling. Records are so bad.

* Set Windows/X11 native window properties

* Fix window resize events getting wrong size

oops

* Remove "using static" from SDL3 WSI

Seriously seems to hurt IDE performance, oh well.

* Apparently I never called CheckThreadApartment().

* Add STAThreadAttribute to sandbox

Necessary for content start

* Set window title on creation properly.

* Load window icons

* Fix GLFW NoTitleBar style handling

Yeah this PR is supposed to be about SDL3, so what?

* Implement more window creation settings in SDL3

Mostly the ones that need a lot of platform-specific stuff to work.

* Make fullscreen work properly in SDL3.

* File dialogs with SDL3

Removes need for swnfd.

* Fix some TODOs

* Fix WebView build

Robust.Client.WebView/Cef/WebViewManagerCef.Control.cs

@@ -484,27 +484,27 @@ namespace Robust.Client.WebView.Cef
             public void FocusEntered()
             {
                 if (_textInputActive)
-                    _clyde.TextInputStart();
+                    Owner.Root?.Window?.TextInputStart();
             }
 
             public void FocusExited()
             {
                 if (_textInputActive)
-                    _clyde.TextInputStop();
+                    Owner.Root?.Window?.TextInputStop();
             }
 
             public void TextInputStart()
             {
                 _textInputActive = true;
                 if (Owner.HasKeyboardFocus())
-                    _clyde.TextInputStart();
+                    Owner.Root?.Window?.TextInputStart();
             }
 
             public void TextInputStop()
             {
                 _textInputActive = false;
                 if (Owner.HasKeyboardFocus())
-                    _clyde.TextInputStop();
+                    Owner.Root?.Window?.TextInputStop();
             }
 
             private sealed class LiveData

Robust.Client/GameController/GameController.Standalone.cs

@@ -23,6 +23,7 @@ namespace Robust.Client
         private Thread? _gameThread;
         private ISawmill _logger = default!;
 
+        [STAThread]
         public static void Main(string[] args)
         {
             Start(args, new GameControllerOptions());

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

@@ -109,8 +109,8 @@ namespace Robust.Client.Graphics.Clyde
                 case "glfw":
                     winImpl = new GlfwWindowingImpl(this, _deps);
                     break;
-                case "sdl2":
-                    winImpl = new Sdl2WindowingImpl(this, _deps);
+                case "sdl3":
+                    winImpl = new Sdl3WindowingImpl(this, _deps);
                     break;
                 default:
                     _logManager.GetSawmill("clyde.win").Log(
@@ -467,26 +467,7 @@ namespace Robust.Client.Graphics.Clyde
             _windowing!.RunOnWindowThread(a);
         }
 
-        public void TextInputSetRect(UIBox2i rect)
-        {
-            DebugTools.AssertNotNull(_windowing);
-
-            _windowing!.TextInputSetRect(rect);
-        }
-
-        public void TextInputStart()
-        {
-            DebugTools.AssertNotNull(_windowing);
-
-            _windowing!.TextInputStart();
-        }
-
-        public void TextInputStop()
-        {
-            DebugTools.AssertNotNull(_windowing);
-
-            _windowing!.TextInputStop();
-        }
+        public IFileDialogManager? FileDialogImpl => _windowing as IFileDialogManager;
 
         private abstract class WindowReg
         {
@@ -590,6 +571,27 @@ namespace Robust.Client.Graphics.Clyde
                 remove => Reg.Resized -= value;
             }
 
+            public void TextInputSetRect(UIBox2i rect, int cursor)
+            {
+                DebugTools.AssertNotNull(_clyde._windowing);
+
+                _clyde._windowing!.TextInputSetRect(Reg, rect, cursor);
+            }
+
+            public void TextInputStart()
+            {
+                DebugTools.AssertNotNull(_clyde._windowing);
+
+                _clyde._windowing!.TextInputStart(Reg);
+            }
+
+            public void TextInputStop()
+            {
+                DebugTools.AssertNotNull(_clyde._windowing);
+
+                _clyde._windowing!.TextInputStop(Reg);
+            }
+
             public nint? WindowsHWnd => _clyde._windowing!.WindowGetWin32Window(Reg);
         }
 

Robust.Client/Graphics/Clyde/ClydeHeadless.cs

@@ -7,6 +7,7 @@ using JetBrains.Annotations;
 using Robust.Client.Audio;
 using Robust.Client.Input;
 using Robust.Client.ResourceManagement;
+using Robust.Client.UserInterface;
 using Robust.Client.UserInterface.CustomControls;
 using Robust.Shared.Graphics;
 using Robust.Shared.Map;
@@ -284,6 +285,8 @@ namespace Robust.Client.Graphics.Clyde
             action();
         }
 
+        public IFileDialogManager? FileDialogImpl => null;
+
         private sealed class DummyCursor : ICursor
         {
             public void Dispose()
@@ -531,6 +534,21 @@ namespace Robust.Client.Graphics.Clyde
             public event Action<WindowDestroyedEventArgs>? Destroyed;
             public event Action<WindowResizedEventArgs>? Resized { add { } remove { } }
 
+            public void TextInputSetRect(UIBox2i rect, int cursor)
+            {
+                // Nop.
+            }
+
+            public void TextInputStart()
+            {
+                // Nop.
+            }
+
+            public void TextInputStop()
+            {
+                // Nop.
+            }
+
             public void MaximizeOnMonitor(IClydeMonitor monitor)
             {
             }

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

@@ -96,7 +96,8 @@ namespace Robust.Client.Graphics.Clyde
 
             private void ProcessEventChar(EventChar ev)
             {
-                if (!_textInputActive)
+                var windowReg = FindWindow(ev.Window);
+                if (windowReg is not { TextInputActive: true })
                     return;
 
                 _clyde.SendText(new TextEnteredEventArgs(new Rune(ev.CodePoint).ToString()));

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

@@ -468,6 +468,8 @@ namespace Robust.Client.Graphics.Clyde
                 GLFW.WindowHint(WindowHintInt.AlphaBits, 8);
                 GLFW.WindowHint(WindowHintInt.StencilBits, 8);
 
+                GLFW.WindowHint(WindowHintBool.Decorated, (parameters.Styles & OSWindowStyles.NoTitleBar) == 0);
+
                 var window = GLFW.CreateWindow(
                     parameters.Width, parameters.Height,
                     parameters.Title,
@@ -485,23 +487,12 @@ namespace Robust.Client.Graphics.Clyde
                     GLFW.MaximizeWindow(window);
                 }
 
-                if ((parameters.Styles & OSWindowStyles.NoTitleBar) != 0)
-                {
-                    GLFW.WindowHint(WindowHintBool.Decorated, false);
-                }
-
                 if ((parameters.Styles & OSWindowStyles.NoTitleOptions) != 0)
                 {
                     if (OperatingSystem.IsWindows())
                     {
                         var hWnd = (HWND) GLFW.GetWin32Window(window);
-                        DebugTools.Assert(hWnd != HWND.NULL);
-
-                        Windows.SetWindowLongPtrW(
-                            hWnd,
-                            GWL.GWL_STYLE,
-                            // Cast to long here to work around a bug in rider with nint bitwise operators.
-                            (nint)((long)Windows.GetWindowLongPtrW(hWnd, GWL.GWL_STYLE) & ~WS.WS_SYSMENU));
+                        WsiShared.SetWindowStyleNoTitleOptionsWindows(hWnd);
                     }
                     else if (OperatingSystem.IsLinux())
                     {
@@ -509,23 +500,7 @@ namespace Robust.Client.Graphics.Clyde
                         {
                             var x11Window = (X11Window)GLFW.GetX11Window(window);
                             var x11Display = (Display*) GLFW.GetX11Display(window);
-                            DebugTools.Assert(x11Window != X11Window.NULL);
-                            // https://specifications.freedesktop.org/wm-spec/wm-spec-latest.html#idm46181547486832
-                            var newPropValString = Marshal.StringToCoTaskMemUTF8("_NET_WM_WINDOW_TYPE_DIALOG");
-                            var newPropVal = Xlib.XInternAtom(x11Display, (sbyte*)newPropValString, Xlib.False);
-                            DebugTools.Assert(newPropVal != Atom.NULL);
-
-                            var propNameString = Marshal.StringToCoTaskMemUTF8("_NET_WM_WINDOW_TYPE");
-#pragma warning disable CA1806
-                            // [display] [window] [property] [type] [format (8, 16,32)] [mode] [data] [element count]
-                            Xlib.XChangeProperty(x11Display, x11Window,
-                                Xlib.XInternAtom(x11Display, (sbyte*)propNameString, Xlib.False), // should never be null; part of spec
-                                Xlib.XA_ATOM, 32, Xlib.PropModeReplace,
-                                (byte*)&newPropVal, 1);
-#pragma warning restore CA1806
-
-                            Marshal.FreeCoTaskMem(newPropValString);
-                            Marshal.FreeCoTaskMem(propNameString);
+                            WsiShared.SetWindowStyleNoTitleOptionsX11(x11Display, x11Window);
                         }
                         catch (EntryPointNotFoundException)
                         {
@@ -643,16 +618,16 @@ namespace Robust.Client.Graphics.Clyde
                 return reg;
             }
 
-            private WindowReg? FindWindow(nint window) => FindWindow((Window*) window);
+            private GlfwWindowReg? FindWindow(nint window) => FindWindow((Window*) window);
 
-            private WindowReg? FindWindow(Window* window)
+            private GlfwWindowReg? FindWindow(Window* window)
             {
                 foreach (var windowReg in _clyde._windows)
                 {
                     var glfwReg = (GlfwWindowReg) windowReg;
                     if (glfwReg.GlfwWindow == window)
                     {
-                        return windowReg;
+                        return glfwReg;
                     }
                 }
 
@@ -739,23 +714,23 @@ namespace Robust.Client.Graphics.Clyde
                 return (void*) GLFW.GetProcAddress(procName);
             }
 
-            public void TextInputSetRect(UIBox2i rect)
+            public void TextInputSetRect(WindowReg reg, UIBox2i rect, int cursor)
             {
                 // Not supported on GLFW.
             }
 
-            public void TextInputStart()
+            public void TextInputStart(WindowReg reg)
             {
                 // Not properly supported on GLFW.
 
-                _textInputActive = true;
+                ((GlfwWindowReg)reg).TextInputActive = true;
             }
 
-            public void TextInputStop()
+            public void TextInputStop(WindowReg reg)
             {
                 // Not properly supported on GLFW.
 
-                _textInputActive = false;
+                ((GlfwWindowReg)reg).TextInputActive = false;
             }
 
             private void CheckWindowDisposed(WindowReg reg)
@@ -770,6 +745,10 @@ namespace Robust.Client.Graphics.Clyde
 
                 // Kept around to avoid it being GCd.
                 public CursorImpl? Cursor;
+
+                // While GLFW does not provide proper IME APIs, we can at least emulate SDL3's StartTextInput() system.
+                // This will ensure some level of consistency between the backends.
+                public bool TextInputActive;
             }
         }
     }

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

@@ -25,10 +25,6 @@ namespace Robust.Client.Graphics.Clyde
             private bool _glfwInitialized;
             private bool _win32Experience;
 
-            // While GLFW does not provide proper IME APIs, we can at least emulate SDL2's StartTextInput() system.
-            // This will ensure some level of consistency between the backends.
-            private bool _textInputActive;
-
             public GlfwWindowingImpl(Clyde clyde, IDependencyCollection deps)
             {
                 _clyde = clyde;

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

@@ -66,9 +66,9 @@ namespace Robust.Client.Graphics.Clyde
             void RunOnWindowThread(Action a);
 
             // IME
-            void TextInputSetRect(UIBox2i rect);
-            void TextInputStart();
-            void TextInputStop();
+            void TextInputSetRect(WindowReg reg, UIBox2i rect, int cursor);
+            void TextInputStart(WindowReg reg);
+            void TextInputStop(WindowReg reg);
             string GetDescription();
         }
     }

Robust.Client/Graphics/Clyde/Windowing/SDL3-CS/LICENSE

@@ -0,0 +1,25 @@
+/* SDL3-CS - C# Bindings for SDL3
+ *
+ * Copyright (c) 2024 Colin Jackson
+ *
+ * This software is provided 'as-is', without any express or implied warranty.
+ * In no event will the authors be held liable for any damages arising from
+ * the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ * claim that you wrote the original software. If you use this software in a
+ * product, an acknowledgment in the product documentation would be
+ * appreciated but is not required.
+ *
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ * misrepresented as being the original software.
+ *
+ * 3. This notice may not be removed or altered from any source distribution.
+ *
+ * Colin "cryy22" Jackson <c@cryy22.art>
+ *
+ */

Robust.Client/Graphics/Clyde/Windowing/SDL3-CS/SDL3.Core.Ext.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace SDL3;
+
+public static partial class SDL
+{
+    // Extensions to SDL3-CS that aren't part of the main library.
+
+    [LibraryImport(nativeLibName)]
+    [UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
+    public static unsafe partial void SDL_SetLogOutputFunction(delegate* unmanaged[Cdecl] <void*, int, SDL_LogPriority, byte*, void> callback, void* userdata);
+
+    [LibraryImport(nativeLibName)]
+    [UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
+    public static unsafe partial SDLBool SDL_AddEventWatch(delegate* unmanaged[Cdecl] <void*, SDL_Event*, byte> filter, void* userdata);
+
+    [LibraryImport(nativeLibName)]
+    [UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
+    public static unsafe partial void SDL_RemoveEventWatch(delegate* unmanaged[Cdecl] <void*, SDL_Event*, byte> filter, void* userdata);
+
+    [LibraryImport(nativeLibName, StringMarshalling = StringMarshalling.Utf8)]
+    [UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
+    public static unsafe partial void SDL_ShowFileDialogWithProperties(int type, delegate* unmanaged[Cdecl]<void*, byte**, int, void> callback, void* userdata, uint properties);
+
+    public const byte SDL_BUTTON_LEFT = 1;
+    public const byte SDL_BUTTON_MIDDLE = 2;
+    public const byte SDL_BUTTON_RIGHT = 3;
+    public const byte SDL_BUTTON_X1 = 4;
+    public const byte SDL_BUTTON_X2 = 5;
+
+    public const int SDL_GL_CONTEXT_PROFILE_CORE = 0x0001;
+    public const int SDL_GL_CONTEXT_PROFILE_COMPATIBILITY = 0x0002;
+    public const int SDL_GL_CONTEXT_PROFILE_ES = 0x0004;
+
+    public const int SDL_GL_CONTEXT_DEBUG_FLAG = 0x0001;
+    public const int SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG = 0x0002;
+    public const int SDL_GL_CONTEXT_ROBUST_ACCESS_FLAG = 0x0004;
+    public const int SDL_GL_CONTEXT_RESET_ISOLATION_FLAG = 0x0008;
+
+    public const int SDL_FILEDIALOG_OPENFILE = 0;
+    public const int SDL_FILEDIALOG_SAVEFILE = 1;
+    public const int SDL_FILEDIALOG_OPENFOLDER = 2;
+
+    public const string SDL_PROP_FILE_DIALOG_NFILTERS_NUMBER = "SDL.filedialog.nfilters";
+    public const string SDL_PROP_FILE_DIALOG_FILTERS_POINTER = "SDL.filedialog.filters";
+
+    public static int SDL_VERSIONNUM_MAJOR(int version) => version / 1000000;
+    public static int SDL_VERSIONNUM_MINOR(int version) => version / 1000 % 1000;
+    public static int SDL_VERSIONNUM_MICRO(int version) => version % 1000;
+}

Robust.Client/Graphics/Clyde/Windowing/Sdl2.Keys.cs

@@ -1,224 +0,0 @@
-using System.Collections.Frozen;
-using System.Collections.Generic;
-using System.Runtime.CompilerServices;
-using System.Threading;
-using Robust.Client.Input;
-using Robust.Shared;
-using static SDL2.SDL;
-using static SDL2.SDL.SDL_Scancode;
-using Key = Robust.Client.Input.Keyboard.Key;
-using Button = Robust.Client.Input.Mouse.Button;
-
-namespace Robust.Client.Graphics.Clyde;
-
-internal partial class Clyde
-{
-    private sealed partial class Sdl2WindowingImpl
-    {
-        // Indices are values of SDL_Scancode
-        private static readonly Key[] KeyMap;
-        private static readonly FrozenDictionary<Key, SDL_Scancode> KeyMapReverse;
-        private static readonly Button[] MouseButtonMap;
-
-        // TODO: to avoid having to ask the windowing thread, key names are cached.
-        private readonly Dictionary<Key, string> _printableKeyNameMap = new();
-
-        private void ReloadKeyMap()
-        {
-            // This may be ran concurrently from the windowing thread.
-            lock (_printableKeyNameMap)
-            {
-                _printableKeyNameMap.Clear();
-
-                // List of mappable keys from SDL2's source appears to be:
-                // entries in SDL_default_keymap that aren't an SDLK_ enum reference.
-                // (the actual logic is more nuanced, but it appears to match the above)
-                // Comes out to these two ranges:
-
-                for (var k = SDL_SCANCODE_A; k <= SDL_SCANCODE_0; k++)
-                {
-                    CacheKey(k);
-                }
-
-                for (var k = SDL_SCANCODE_MINUS; k <= SDL_SCANCODE_SLASH; k++)
-                {
-                    CacheKey(k);
-                }
-
-                void CacheKey(SDL_Scancode scancode)
-                {
-                    var rKey = ConvertSdl2Scancode(scancode);
-                    if (rKey == Key.Unknown)
-                        return;
-
-                    var name = SDL_GetKeyName(SDL_GetKeyFromScancode(scancode));
-
-                    if (!string.IsNullOrEmpty(name))
-                        _printableKeyNameMap.Add(rKey, name);
-                }
-            }
-        }
-
-        public string? KeyGetName(Key key)
-        {
-            lock (_printableKeyNameMap)
-            {
-                if (_printableKeyNameMap.TryGetValue(key, out var name))
-                    return name;
-
-                return null;
-            }
-        }
-
-        internal static Key ConvertSdl2Scancode(SDL_Scancode scancode)
-        {
-            return KeyMap[(int) scancode];
-        }
-
-        public static Button ConvertSdl2Button(int button)
-        {
-            return MouseButtonMap[button];
-        }
-
-        static Sdl2WindowingImpl()
-        {
-            MouseButtonMap = new Button[6];
-            MouseButtonMap[SDL_BUTTON_LEFT] = Button.Left;
-            MouseButtonMap[SDL_BUTTON_RIGHT] = Button.Right;
-            MouseButtonMap[SDL_BUTTON_MIDDLE] = Button.Middle;
-            MouseButtonMap[SDL_BUTTON_X1] = Button.Button4;
-            MouseButtonMap[SDL_BUTTON_X2] = Button.Button5;
-
-            KeyMap = new Key[(int) SDL_NUM_SCANCODES];
-            MapKey(SDL_SCANCODE_A, Key.A);
-            MapKey(SDL_SCANCODE_B, Key.B);
-            MapKey(SDL_SCANCODE_C, Key.C);
-            MapKey(SDL_SCANCODE_D, Key.D);
-            MapKey(SDL_SCANCODE_E, Key.E);
-            MapKey(SDL_SCANCODE_F, Key.F);
-            MapKey(SDL_SCANCODE_G, Key.G);
-            MapKey(SDL_SCANCODE_H, Key.H);
-            MapKey(SDL_SCANCODE_I, Key.I);
-            MapKey(SDL_SCANCODE_J, Key.J);
-            MapKey(SDL_SCANCODE_K, Key.K);
-            MapKey(SDL_SCANCODE_L, Key.L);
-            MapKey(SDL_SCANCODE_M, Key.M);
-            MapKey(SDL_SCANCODE_N, Key.N);
-            MapKey(SDL_SCANCODE_O, Key.O);
-            MapKey(SDL_SCANCODE_P, Key.P);
-            MapKey(SDL_SCANCODE_Q, Key.Q);
-            MapKey(SDL_SCANCODE_R, Key.R);
-            MapKey(SDL_SCANCODE_S, Key.S);
-            MapKey(SDL_SCANCODE_T, Key.T);
-            MapKey(SDL_SCANCODE_U, Key.U);
-            MapKey(SDL_SCANCODE_V, Key.V);
-            MapKey(SDL_SCANCODE_W, Key.W);
-            MapKey(SDL_SCANCODE_X, Key.X);
-            MapKey(SDL_SCANCODE_Y, Key.Y);
-            MapKey(SDL_SCANCODE_Z, Key.Z);
-            MapKey(SDL_SCANCODE_0, Key.Num0);
-            MapKey(SDL_SCANCODE_1, Key.Num1);
-            MapKey(SDL_SCANCODE_2, Key.Num2);
-            MapKey(SDL_SCANCODE_3, Key.Num3);
-            MapKey(SDL_SCANCODE_4, Key.Num4);
-            MapKey(SDL_SCANCODE_5, Key.Num5);
-            MapKey(SDL_SCANCODE_6, Key.Num6);
-            MapKey(SDL_SCANCODE_7, Key.Num7);
-            MapKey(SDL_SCANCODE_8, Key.Num8);
-            MapKey(SDL_SCANCODE_9, Key.Num9);
-            MapKey(SDL_SCANCODE_KP_0, Key.NumpadNum0);
-            MapKey(SDL_SCANCODE_KP_1, Key.NumpadNum1);
-            MapKey(SDL_SCANCODE_KP_2, Key.NumpadNum2);
-            MapKey(SDL_SCANCODE_KP_3, Key.NumpadNum3);
-            MapKey(SDL_SCANCODE_KP_4, Key.NumpadNum4);
-            MapKey(SDL_SCANCODE_KP_5, Key.NumpadNum5);
-            MapKey(SDL_SCANCODE_KP_6, Key.NumpadNum6);
-            MapKey(SDL_SCANCODE_KP_7, Key.NumpadNum7);
-            MapKey(SDL_SCANCODE_KP_8, Key.NumpadNum8);
-            MapKey(SDL_SCANCODE_KP_9, Key.NumpadNum9);
-            MapKey(SDL_SCANCODE_ESCAPE, Key.Escape);
-            MapKey(SDL_SCANCODE_LCTRL, Key.Control);
-            MapKey(SDL_SCANCODE_RCTRL, Key.Control);
-            MapKey(SDL_SCANCODE_RSHIFT, Key.Shift);
-            MapKey(SDL_SCANCODE_LSHIFT, Key.Shift);
-            MapKey(SDL_SCANCODE_LALT, Key.Alt);
-            MapKey(SDL_SCANCODE_RALT, Key.Alt);
-            MapKey(SDL_SCANCODE_LGUI, Key.LSystem);
-            MapKey(SDL_SCANCODE_RGUI, Key.RSystem);
-            MapKey(SDL_SCANCODE_MENU, Key.Menu);
-            MapKey(SDL_SCANCODE_LEFTBRACKET, Key.LBracket);
-            MapKey(SDL_SCANCODE_RIGHTBRACKET, Key.RBracket);
-            MapKey(SDL_SCANCODE_SEMICOLON, Key.SemiColon);
-            MapKey(SDL_SCANCODE_COMMA, Key.Comma);
-            MapKey(SDL_SCANCODE_PERIOD, Key.Period);
-            MapKey(SDL_SCANCODE_APOSTROPHE, Key.Apostrophe);
-            MapKey(SDL_SCANCODE_SLASH, Key.Slash);
-            MapKey(SDL_SCANCODE_BACKSLASH, Key.BackSlash);
-            MapKey(SDL_SCANCODE_GRAVE, Key.Tilde);
-            MapKey(SDL_SCANCODE_EQUALS, Key.Equal);
-            MapKey(SDL_SCANCODE_SPACE, Key.Space);
-            MapKey(SDL_SCANCODE_RETURN, Key.Return);
-            MapKey(SDL_SCANCODE_KP_ENTER, Key.NumpadEnter);
-            MapKey(SDL_SCANCODE_BACKSPACE, Key.BackSpace);
-            MapKey(SDL_SCANCODE_TAB, Key.Tab);
-            MapKey(SDL_SCANCODE_PAGEUP, Key.PageUp);
-            MapKey(SDL_SCANCODE_PAGEDOWN, Key.PageDown);
-            MapKey(SDL_SCANCODE_END, Key.End);
-            MapKey(SDL_SCANCODE_HOME, Key.Home);
-            MapKey(SDL_SCANCODE_INSERT, Key.Insert);
-            MapKey(SDL_SCANCODE_DELETE, Key.Delete);
-            MapKey(SDL_SCANCODE_MINUS, Key.Minus);
-            MapKey(SDL_SCANCODE_KP_PLUS, Key.NumpadAdd);
-            MapKey(SDL_SCANCODE_KP_MINUS, Key.NumpadSubtract);
-            MapKey(SDL_SCANCODE_KP_DIVIDE, Key.NumpadDivide);
-            MapKey(SDL_SCANCODE_KP_MULTIPLY, Key.NumpadMultiply);
-            MapKey(SDL_SCANCODE_KP_DECIMAL, Key.NumpadDecimal);
-            MapKey(SDL_SCANCODE_LEFT, Key.Left);
-            MapKey(SDL_SCANCODE_RIGHT, Key.Right);
-            MapKey(SDL_SCANCODE_UP, Key.Up);
-            MapKey(SDL_SCANCODE_DOWN, Key.Down);
-            MapKey(SDL_SCANCODE_F1, Key.F1);
-            MapKey(SDL_SCANCODE_F2, Key.F2);
-            MapKey(SDL_SCANCODE_F3, Key.F3);
-            MapKey(SDL_SCANCODE_F4, Key.F4);
-            MapKey(SDL_SCANCODE_F5, Key.F5);
-            MapKey(SDL_SCANCODE_F6, Key.F6);
-            MapKey(SDL_SCANCODE_F7, Key.F7);
-            MapKey(SDL_SCANCODE_F8, Key.F8);
-            MapKey(SDL_SCANCODE_F9, Key.F9);
-            MapKey(SDL_SCANCODE_F10, Key.F10);
-            MapKey(SDL_SCANCODE_F11, Key.F11);
-            MapKey(SDL_SCANCODE_F12, Key.F12);
-            MapKey(SDL_SCANCODE_F13, Key.F13);
-            MapKey(SDL_SCANCODE_F14, Key.F14);
-            MapKey(SDL_SCANCODE_F15, Key.F15);
-            MapKey(SDL_SCANCODE_F16, Key.F16);
-            MapKey(SDL_SCANCODE_F17, Key.F17);
-            MapKey(SDL_SCANCODE_F18, Key.F18);
-            MapKey(SDL_SCANCODE_F19, Key.F19);
-            MapKey(SDL_SCANCODE_F20, Key.F20);
-            MapKey(SDL_SCANCODE_F21, Key.F21);
-            MapKey(SDL_SCANCODE_F22, Key.F22);
-            MapKey(SDL_SCANCODE_F23, Key.F23);
-            MapKey(SDL_SCANCODE_F24, Key.F24);
-            MapKey(SDL_SCANCODE_PAUSE, Key.Pause);
-
-            var keyMapReverse = new Dictionary<Key, SDL_Scancode>();
-
-            for (var code = 0; code < KeyMap.Length; code++)
-            {
-                var key = KeyMap[code];
-                if (key != Key.Unknown)
-                    keyMapReverse[key] = (SDL_Scancode) code;
-            }
-
-            KeyMapReverse = keyMapReverse.ToFrozenDictionary();
-
-            [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            static void MapKey(SDL_Scancode code, Key key)
-            {
-                KeyMap[(int)code] = key;
-            }
-        }
-    }
-}

Robust.Client/Graphics/Clyde/Windowing/Sdl2.Monitors.cs

@@ -1,133 +0,0 @@
-using System.Collections.Generic;
-using System.Runtime.CompilerServices;
-using SDL2;
-
-namespace Robust.Client.Graphics.Clyde;
-
-internal partial class Clyde
-{
-    private sealed partial class Sdl2WindowingImpl
-    {
-        // NOTE: SDL2 calls them "displays". GLFW calls them monitors. GLFW's is the one I'm going with.
-
-        // Can't use ClydeHandle because it's not thread safe to allocate.
-        private int _nextMonitorId = 1;
-
-        private readonly Dictionary<int, WinThreadMonitorReg> _winThreadMonitors = new();
-        private readonly Dictionary<int, Sdl2MonitorReg> _monitors = new();
-
-        private void InitMonitors()
-        {
-            var numDisplays = SDL.SDL_GetNumVideoDisplays();
-            for (var i = 0; i < numDisplays; i++)
-            {
-                // SDL.SDL_GetDisplayDPI(i, out var ddpi, out var hdpi, out var vdpi);
-                // _sawmill.Info($"[{i}] {ddpi} {hdpi} {vdpi}");
-                WinThreadSetupMonitor(i);
-            }
-        }
-
-        [MethodImpl(MethodImplOptions.NoInlining)]
-        private void WinThreadSetupMonitor(int displayIdx)
-        {
-            var id = _nextMonitorId++;
-
-            var name = SDL.SDL_GetDisplayName(displayIdx);
-            var modeCount = SDL.SDL_GetNumDisplayModes(displayIdx);
-            SDL.SDL_GetCurrentDisplayMode(displayIdx, out var curMode);
-            var modes = new VideoMode[modeCount];
-            for (var i = 0; i < modes.Length; i++)
-            {
-                SDL.SDL_GetDisplayMode(displayIdx, i, out var mode);
-                modes[i] = ConvertVideoMode(mode);
-            }
-
-            _winThreadMonitors.Add(id, new WinThreadMonitorReg { Id = id, DisplayIdx = displayIdx });
-
-            SendEvent(new EventMonitorSetup(id, name, ConvertVideoMode(curMode), modes));
-
-            if (displayIdx == 0)
-                _clyde._primaryMonitorId = id;
-        }
-
-        private static VideoMode ConvertVideoMode(in SDL.SDL_DisplayMode mode)
-        {
-            return new()
-            {
-                Width = (ushort)mode.w,
-                Height = (ushort)mode.h,
-                RefreshRate = (ushort)mode.refresh_rate,
-                // TODO: set bits count based on format (I'm lazy)
-                RedBits = 8,
-                GreenBits = 8,
-                BlueBits = 8,
-            };
-        }
-
-        private void ProcessSetupMonitor(EventMonitorSetup ev)
-        {
-            var impl = new MonitorHandle(
-                ev.Id,
-                ev.Name,
-                (ev.CurrentMode.Width, ev.CurrentMode.Height),
-                ev.CurrentMode.RefreshRate,
-                ev.AllModes);
-
-            _clyde._monitorHandles.Add(ev.Id, impl);
-            _monitors[ev.Id] = new Sdl2MonitorReg
-            {
-                Id = ev.Id,
-                Handle = impl
-            };
-        }
-
-        private void WinThreadDestroyMonitor(int displayIdx)
-        {
-            var monitorId = 0;
-
-            foreach (var (id, monitorReg) in _winThreadMonitors)
-            {
-                if (monitorReg.DisplayIdx == displayIdx)
-                {
-                    monitorId = id;
-                    break;
-                }
-            }
-
-            if (monitorId == 0)
-                return;
-
-            // So SDL2 doesn't have a very nice indexing system for monitors like GLFW does.
-            // This means that, when a monitor is disconnected, all monitors *after* it get shifted down one slot.
-            // Now, this happens *after* the event is fired, to make matters worse.
-            // So we're basically trying to match unspecified SDL2 internals here. Great.
-
-            _winThreadMonitors.Remove(monitorId);
-
-            foreach (var (_, reg) in _winThreadMonitors)
-            {
-                if (reg.DisplayIdx > displayIdx)
-                    reg.DisplayIdx -= 1;
-            }
-
-            SendEvent(new EventMonitorDestroy(monitorId));
-        }
-
-        private void ProcessEventDestroyMonitor(EventMonitorDestroy ev)
-        {
-            _monitors.Remove(ev.Id);
-            _clyde._monitorHandles.Remove(ev.Id);
-        }
-
-        private sealed class Sdl2MonitorReg : MonitorReg
-        {
-            public int Id;
-        }
-
-        private sealed class WinThreadMonitorReg
-        {
-            public int Id;
-            public int DisplayIdx;
-        }
-    }
-}

Robust.Client/Graphics/Clyde/Windowing/Sdl2.RawEvents.cs

@@ -1,316 +0,0 @@
-using System;
-using System.Diagnostics.CodeAnalysis;
-using System.Runtime.CompilerServices;
-using System.Runtime.InteropServices;
-using System.Threading.Tasks;
-using Robust.Shared.Maths;
-using TerraFX.Interop.Windows;
-using static SDL2.SDL;
-using static SDL2.SDL.SDL_EventType;
-using static SDL2.SDL.SDL_SYSWM_TYPE;
-using static SDL2.SDL.SDL_WindowEventID;
-
-namespace Robust.Client.Graphics.Clyde;
-
-internal partial class Clyde
-{
-    private sealed partial class Sdl2WindowingImpl
-    {
-        [UnmanagedCallersOnly(CallConvs = new []{typeof(CallConvCdecl)})]
-        private static unsafe int EventWatch(void* userdata, SDL_Event* sdlevent)
-        {
-            var obj = (Sdl2WindowingImpl) GCHandle.FromIntPtr((IntPtr)userdata).Target!;
-            ref readonly var ev = ref *sdlevent;
-
-            obj.ProcessSdl2Event(in ev);
-
-            return 0;
-        }
-
-        private void ProcessSdl2Event(in SDL_Event ev)
-        {
-            switch (ev.type)
-            {
-                case SDL_WINDOWEVENT:
-                    ProcessSdl2EventWindow(in ev.window);
-                    break;
-                case SDL_KEYDOWN:
-                case SDL_KEYUP:
-                    ProcessSdl2KeyEvent(in ev.key);
-                    break;
-                case SDL_TEXTINPUT:
-                    ProcessSdl2EventTextInput(in ev.text);
-                    break;
-                case SDL_TEXTEDITING:
-                    ProcessSdl2EventTextEditing(in ev.edit);
-                    break;
-                case SDL_KEYMAPCHANGED:
-                    ProcessSdl2EventKeyMapChanged();
-                    break;
-                case SDL_TEXTEDITING_EXT:
-                    ProcessSdl2EventTextEditingExt(in ev.editExt);
-                    break;
-                case SDL_MOUSEMOTION:
-                    ProcessSdl2EventMouseMotion(in ev.motion);
-                    break;
-                case SDL_MOUSEBUTTONDOWN:
-                case SDL_MOUSEBUTTONUP:
-                    ProcessSdl2EventMouseButton(in ev.button);
-                    break;
-                case SDL_MOUSEWHEEL:
-                    ProcessSdl2EventMouseWheel(in ev.wheel);
-                    break;
-                case SDL_DISPLAYEVENT:
-                    ProcessSdl2EventDisplay(in ev.display);
-                    break;
-                case SDL_SYSWMEVENT:
-                    ProcessSdl2EventSysWM(in ev.syswm);
-                    break;
-                case SDL_QUIT:
-                    ProcessSdl2EventQuit();
-                    break;
-            }
-        }
-
-        private void ProcessSdl2EventQuit()
-        {
-            SendEvent(new EventQuit());
-        }
-
-        private void ProcessSdl2EventDisplay(in SDL_DisplayEvent evDisplay)
-        {
-            switch (evDisplay.displayEvent)
-            {
-                case SDL_DisplayEventID.SDL_DISPLAYEVENT_CONNECTED:
-                    WinThreadSetupMonitor((int) evDisplay.display);
-                    break;
-                case SDL_DisplayEventID.SDL_DISPLAYEVENT_DISCONNECTED:
-                    WinThreadDestroyMonitor((int) evDisplay.display);
-                    break;
-            }
-        }
-
-        private void ProcessSdl2EventMouseWheel(in SDL_MouseWheelEvent ev)
-        {
-            SendEvent(new EventWheel(ev.windowID, ev.preciseX, ev.preciseY));
-        }
-
-        private void ProcessSdl2EventMouseButton(in SDL_MouseButtonEvent ev)
-        {
-            SendEvent(new EventMouseButton(ev.windowID, ev.type, ev.button));
-        }
-
-        private void ProcessSdl2EventMouseMotion(in SDL_MouseMotionEvent ev)
-        {
-            // _sawmill.Info($"{evMotion.x}, {evMotion.y}, {evMotion.xrel}, {evMotion.yrel}");
-            SendEvent(new EventMouseMotion(ev.windowID, ev.x, ev.y, ev.xrel, ev.yrel));
-        }
-
-        private unsafe void ProcessSdl2EventTextInput(in SDL_TextInputEvent ev)
-        {
-            fixed (byte* text = ev.text)
-            {
-                var str = Marshal.PtrToStringUTF8((IntPtr)text) ?? "";
-                // _logManager.GetSawmill("ime").Debug($"Input: {str}");
-                SendEvent(new EventText(ev.windowID, str));
-            }
-        }
-
-        private unsafe void ProcessSdl2EventTextEditing(in SDL_TextEditingEvent ev)
-        {
-            fixed (byte* text = ev.text)
-            {
-                SendTextEditing(ev.windowID, text, ev.start, ev.length);
-            }
-        }
-
-        private unsafe void ProcessSdl2EventTextEditingExt(in SDL_TextEditingExtEvent ev)
-        {
-            SendTextEditing(ev.windowID, (byte*) ev.text, ev.start, ev.length);
-            SDL_free(ev.text);
-        }
-
-        private unsafe void SendTextEditing(uint window, byte* text, int start, int length)
-        {
-            var str = Marshal.PtrToStringUTF8((nint) text) ?? "";
-            // _logManager.GetSawmill("ime").Debug($"Editing: '{str}', start: {start}, len: {length}");
-            SendEvent(new EventTextEditing(window, str, start, length));
-        }
-
-        private void ProcessSdl2EventKeyMapChanged()
-        {
-            ReloadKeyMap();
-            SendEvent(new EventKeyMapChanged());
-        }
-
-        private void ProcessSdl2KeyEvent(in SDL_KeyboardEvent ev)
-        {
-            SendEvent(new EventKey(
-                ev.windowID,
-                ev.keysym.scancode,
-                ev.type,
-                ev.repeat != 0,
-                ev.keysym.mod));
-        }
-
-        private void ProcessSdl2EventWindow(in SDL_WindowEvent ev)
-        {
-            var window = SDL_GetWindowFromID(ev.windowID);
-
-            switch (ev.windowEvent)
-            {
-                case SDL_WINDOWEVENT_SIZE_CHANGED:
-                    var width = ev.data1;
-                    var height = ev.data2;
-                    SDL_GetWindowSizeInPixels(window, out var fbW, out var fbH);
-                    var (xScale, yScale) = GetWindowScale(window);
-
-                    _sawmill.Debug($"{width}x{height}, {fbW}x{fbH}, {xScale}x{yScale}");
-
-                    SendEvent(new EventWindowSize(ev.windowID, width, height, fbW, fbH, xScale, yScale));
-                    break;
-
-                default:
-                    SendEvent(new EventWindow(ev.windowID, ev.windowEvent));
-                    break;
-            }
-        }
-
-        // ReSharper disable once InconsistentNaming
-        private unsafe void ProcessSdl2EventSysWM(in SDL_SysWMEvent ev)
-        {
-            ref readonly var sysWmMessage = ref *(SDL_SysWMmsg*)ev.msg;
-            if (sysWmMessage.subsystem != SDL_SYSWM_WINDOWS)
-                return;
-
-            ref readonly var winMessage = ref *(SDL_SysWMmsgWin32*)ev.msg;
-            if (winMessage.msg is WM.WM_KEYDOWN or WM.WM_KEYUP)
-            {
-                TryWin32VirtualVKey(in winMessage);
-            }
-        }
-
-        private void TryWin32VirtualVKey(in SDL_SysWMmsgWin32 msg)
-        {
-            // Workaround for https://github.com/ocornut/imgui/issues/2977
-            // This is gonna bite me in the ass if SDL2 ever fixes this upstream, isn't it...
-            // (I spent disproportionate amounts of effort on this).
-
-            // Code for V key.
-            if ((int)msg.wParam is not (0x56 or VK.VK_CONTROL))
-                return;
-
-            var scanCode = (msg.lParam >> 16) & 0xFF;
-            if (scanCode != 0)
-                return;
-
-            SendEvent(new EventWindowsFakeV(msg.hwnd, msg.msg, msg.wParam));
-        }
-
-        private abstract record EventBase;
-
-        private record EventWindowCreate(
-            Sdl2WindowCreateResult Result,
-            TaskCompletionSource<Sdl2WindowCreateResult> Tcs
-        ) : EventBase;
-
-        private record EventKey(
-            uint WindowId,
-            SDL_Scancode Scancode,
-            SDL_EventType Type,
-            bool Repeat,
-            SDL_Keymod Mods
-        ) : EventBase;
-
-        private record EventMouseMotion(
-            uint WindowId,
-            int X, int Y,
-            int XRel, int YRel
-        ) : EventBase;
-
-        private record EventMouseButton(
-            uint WindowId,
-            SDL_EventType Type,
-            byte Button
-        ) : EventBase;
-
-        private record EventText(
-            uint WindowId,
-            string Text
-        ) : EventBase;
-
-        private record EventTextEditing(
-            uint WindowId,
-            string Text,
-            int Start,
-            int Length
-        ) : EventBase;
-
-        private record EventWindowSize(
-            uint WindowId,
-            int Width,
-            int Height,
-            int FramebufferWidth,
-            int FramebufferHeight,
-            float XScale,
-            float YScale
-        ) : EventBase;
-
-        private record EventWheel(
-            uint WindowId,
-            float XOffset,
-            float YOffset
-        ) : EventBase;
-
-        // SDL_WindowEvents that don't have special handling like size.
-        private record EventWindow(
-            uint WindowId,
-            SDL_WindowEventID EventId
-        ) : EventBase;
-
-        private record EventMonitorSetup
-        (
-            int Id,
-            string Name,
-            VideoMode CurrentMode,
-            VideoMode[] AllModes
-        ) : EventBase;
-
-        private record EventMonitorDestroy
-        (
-            int Id
-        ) : EventBase;
-
-        private record EventWindowsFakeV(HWND Window,
-            uint Message, WPARAM WParam) : EventBase;
-
-        private record EventKeyMapChanged : EventBase;
-        private record EventQuit : EventBase;
-
-        [StructLayout(LayoutKind.Sequential)]
-        [SuppressMessage("ReSharper", "InconsistentNaming")]
-        [SuppressMessage("ReSharper", "IdentifierTypo")]
-        [SuppressMessage("ReSharper", "FieldCanBeMadeReadOnly.Local")]
-        [SuppressMessage("ReSharper", "MemberCanBePrivate.Local")]
-        private struct SDL_SysWMmsg
-        {
-            public SDL_version version;
-            public SDL_SYSWM_TYPE subsystem;
-        }
-
-        [StructLayout(LayoutKind.Sequential)]
-        [SuppressMessage("ReSharper", "InconsistentNaming")]
-        [SuppressMessage("ReSharper", "IdentifierTypo")]
-        [SuppressMessage("ReSharper", "FieldCanBeMadeReadOnly.Local")]
-        [SuppressMessage("ReSharper", "MemberCanBePrivate.Local")]
-        private struct SDL_SysWMmsgWin32
-        {
-            public SDL_version version;
-            public SDL_SYSWM_TYPE subsystem;
-            public HWND hwnd;
-            public uint msg;
-            public WPARAM wParam;
-            public LPARAM lParam;
-        }
-    }
-}

Robust.Client/Graphics/Clyde/Windowing/Sdl2.Windows.cs

@@ -1,586 +0,0 @@
-using System;
-using System.Numerics;
-using System.Runtime.CompilerServices;
-using System.Threading.Tasks;
-using Robust.Shared.Map;
-using Robust.Shared.Maths;
-using Robust.Shared.Utility;
-using static SDL2.SDL;
-using static SDL2.SDL.SDL_bool;
-using static SDL2.SDL.SDL_FlashOperation;
-using static SDL2.SDL.SDL_GLattr;
-using static SDL2.SDL.SDL_GLcontext;
-using static SDL2.SDL.SDL_GLprofile;
-using static SDL2.SDL.SDL_SYSWM_TYPE;
-using static SDL2.SDL.SDL_WindowFlags;
-using BOOL = TerraFX.Interop.Windows.BOOL;
-using HWND = TerraFX.Interop.Windows.HWND;
-using GWLP = TerraFX.Interop.Windows.GWLP;
-using Windows = TerraFX.Interop.Windows.Windows;
-
-namespace Robust.Client.Graphics.Clyde;
-
-internal partial class Clyde
-{
-    private sealed partial class Sdl2WindowingImpl
-    {
-        private int _nextWindowId = 1;
-
-        public (WindowReg?, string? error) WindowCreate(
-            GLContextSpec? spec,
-            WindowCreateParameters parameters,
-            WindowReg? share,
-            WindowReg? owner)
-        {
-            nint shareWindow = 0;
-            nint shareContext = 0;
-            if (share is Sdl2WindowReg shareReg)
-            {
-                shareWindow = shareReg.Sdl2Window;
-                shareContext = shareReg.GlContext;
-            }
-
-            nint ownerPtr = 0;
-            if (owner is Sdl2WindowReg ownerReg)
-                ownerPtr = ownerReg.Sdl2Window;
-
-            var task = SharedWindowCreate(spec, parameters, shareWindow, shareContext, ownerPtr);
-
-            // Block the main thread (to avoid stuff like texture uploads being problematic).
-            WaitWindowCreate(task);
-
-#pragma warning disable RA0004
-            // Block above ensured task is done, this is safe.
-            var (reg, error) = task.Result;
-#pragma warning restore RA0004
-            if (reg != null)
-            {
-                reg.Owner = reg.Handle;
-            }
-
-            return (reg, error);
-        }
-
-        private void WaitWindowCreate(Task<Sdl2WindowCreateResult> windowTask)
-        {
-            while (!windowTask.IsCompleted)
-            {
-                // Keep processing events until the window task gives either an error or success.
-                WaitEvents();
-                ProcessEvents(single: true);
-            }
-        }
-
-        private Task<Sdl2WindowCreateResult> SharedWindowCreate(
-            GLContextSpec? glSpec,
-            WindowCreateParameters parameters,
-            nint shareWindow,
-            nint shareContext,
-            nint 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<Sdl2WindowCreateResult>();
-            SendCmd(new CmdWinCreate(glSpec, parameters, shareWindow, shareContext, owner, tcs));
-            return tcs.Task;
-        }
-
-        private static void FinishWindowCreate(EventWindowCreate ev)
-        {
-            var (res, tcs) = ev;
-
-            tcs.TrySetResult(res);
-        }
-
-        private void WinThreadWinCreate(CmdWinCreate cmd)
-        {
-            var (glSpec, parameters, shareWindow, shareContext, owner, tcs) = cmd;
-
-            var (window, context) = CreateSdl2WindowForRenderer(glSpec, parameters, shareWindow, shareContext, owner);
-
-            if (window == 0)
-            {
-                var err = SDL_GetError();
-
-                SendEvent(new EventWindowCreate(new Sdl2WindowCreateResult(null, err), tcs));
-                return;
-            }
-
-            // We can't invoke the TCS directly from the windowing thread because:
-            // * it'd hit the synchronization context,
-            //   which would make (blocking) main window init more annoying.
-            // * it'd not be synchronized to other incoming window events correctly which might be icky.
-            // So we send the TCS back to the game thread
-            // which processes events in the correct order and has better control of stuff during init.
-            var reg = WinThreadSetupWindow(window, context);
-
-            SendEvent(new EventWindowCreate(new Sdl2WindowCreateResult(reg, null), tcs));
-        }
-
-        private static void WinThreadWinDestroy(CmdWinDestroy cmd)
-        {
-            if (OperatingSystem.IsWindows() && cmd.HadOwner)
-            {
-                // On Windows, closing the child window causes the owner to be minimized, apparently.
-                // Clear owner on close to avoid this.
-
-                SDL_SysWMinfo wmInfo = default;
-                SDL_VERSION(out wmInfo.version);
-                if (SDL_GetWindowWMInfo(cmd.Window, ref wmInfo) == SDL_TRUE && wmInfo.subsystem == SDL_SYSWM_WINDOWS)
-                {
-                    var hWnd = (HWND)wmInfo.info.win.window;
-                    DebugTools.Assert(hWnd != HWND.NULL);
-
-                    Windows.SetWindowLongPtrW(
-                        hWnd,
-                        GWLP.GWLP_HWNDPARENT,
-                        0);
-                }
-            }
-
-            SDL_DestroyWindow(cmd.Window);
-        }
-
-        private (nint window, nint context) CreateSdl2WindowForRenderer(
-            GLContextSpec? spec,
-            WindowCreateParameters parameters,
-            nint shareWindow,
-            nint shareContext,
-            nint ownerWindow)
-        {
-            var windowFlags = SDL_WINDOW_HIDDEN | SDL_WINDOW_RESIZABLE;
-
-            if (spec is { } s)
-            {
-                windowFlags |= SDL_WINDOW_OPENGL;
-
-                SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8);
-                SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8);
-                SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
-                SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
-                SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
-                SDL_GL_SetAttribute(SDL_GL_FRAMEBUFFER_SRGB_CAPABLE, s.Profile == GLContextProfile.Es ? 0 : 1);
-                SDL_GLcontext ctxFlags = 0;
-#if DEBUG
-                ctxFlags |= SDL_GL_CONTEXT_DEBUG_FLAG;
-#endif
-                if (s.Profile == GLContextProfile.Core)
-                    ctxFlags |= SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG;
-
-                SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, (int)ctxFlags);
-
-                if (shareContext != 0)
-                {
-                    SDL_GL_MakeCurrent(shareWindow, shareContext);
-                    SDL_GL_SetAttribute(SDL_GL_SHARE_WITH_CURRENT_CONTEXT, 1);
-                }
-                else
-                {
-                    SDL_GL_SetAttribute(SDL_GL_SHARE_WITH_CURRENT_CONTEXT, 0);
-                }
-
-                var profile = s.Profile switch
-                {
-                    GLContextProfile.Compatibility => SDL_GL_CONTEXT_PROFILE_COMPATIBILITY,
-                    GLContextProfile.Core => SDL_GL_CONTEXT_PROFILE_CORE,
-                    GLContextProfile.Es => SDL_GL_CONTEXT_PROFILE_ES,
-                    _ => SDL_GL_CONTEXT_PROFILE_COMPATIBILITY,
-                };
-
-                SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, profile);
-                SDL_SetHint("SDL_OPENGL_ES_DRIVER", s.CreationApi == GLContextCreationApi.Egl ? "1" : "0");
-
-                SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, s.Major);
-                SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, s.Minor);
-
-                if (s.CreationApi == GLContextCreationApi.Egl)
-                    WsiShared.EnsureEglAvailable();
-            }
-
-            if (OperatingSystem.IsMacOS())
-            {
-                windowFlags |= SDL_WINDOW_ALLOW_HIGHDPI;
-            }
-
-            if (parameters.Fullscreen)
-            {
-                windowFlags |= SDL_WINDOW_FULLSCREEN_DESKTOP;
-            }
-
-            nint window = SDL_CreateWindow(
-                "",
-                SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
-                parameters.Width, parameters.Height,
-                windowFlags);
-
-            if (window == 0)
-                return default;
-
-            nint glContext = SDL_GL_CreateContext(window);
-            if (glContext == 0)
-            {
-                SDL_DestroyWindow(window);
-                return default;
-            }
-
-            // TODO: Monitors, window maximize.
-            // TODO: a bunch of win32 calls for funny window properties I still haven't ported to other platforms.
-
-            // Make sure window thread doesn't keep hold of the GL context.
-            SDL_GL_MakeCurrent(IntPtr.Zero, IntPtr.Zero);
-
-
-            if (OperatingSystem.IsWindows())
-            {
-                SDL_SysWMinfo info = default;
-                SDL_VERSION(out info.version);
-                if (SDL_GetWindowWMInfo(window, ref info) == SDL_TRUE && info.subsystem == SDL_SYSWM_WINDOWS)
-                    WsiShared.WindowsSharedWindowCreate((HWND) info.info.win.window, _cfg);
-            }
-
-            if (parameters.Visible)
-                SDL_ShowWindow(window);
-
-            return (window, glContext);
-        }
-
-        private unsafe Sdl2WindowReg WinThreadSetupWindow(nint window, nint context)
-        {
-            var reg = new Sdl2WindowReg
-            {
-                Sdl2Window = window,
-                GlContext = context,
-                WindowId = SDL_GetWindowID(window),
-                Id = new WindowId(_nextWindowId++)
-            };
-            var handle = new WindowHandle(_clyde, reg);
-            reg.Handle = handle;
-
-            SDL_VERSION(out reg.SysWMinfo.version);
-            var res = SDL_GetWindowWMInfo(window, ref reg.SysWMinfo);
-            if (res == SDL_FALSE)
-                _sawmill.Error("Failed to get window WM info: {error}", SDL_GetError());
-
-            // LoadWindowIcon(window);
-
-            SDL_GetWindowSizeInPixels(window, out var fbW, out var fbH);
-            reg.FramebufferSize = (fbW, fbH);
-
-            reg.WindowScale = GetWindowScale(window);
-
-            SDL_GetWindowSize(window, out var w, out var h);
-            reg.PrevWindowSize = reg.WindowSize = (w, h);
-
-            SDL_GetWindowPosition(window, out var x, out var y);
-            reg.PrevWindowPos = (x, y);
-
-            reg.PixelRatio = reg.FramebufferSize / (Vector2) reg.WindowSize;
-
-            return reg;
-        }
-
-        public void WindowDestroy(WindowReg window)
-        {
-            var reg = (Sdl2WindowReg) window;
-            SendCmd(new CmdWinDestroy(reg.Sdl2Window, window.Owner != null));
-        }
-
-        public void UpdateMainWindowMode()
-        {
-            if (_clyde._mainWindow == null)
-                return;
-
-            var win = (Sdl2WindowReg) _clyde._mainWindow;
-
-            SendCmd(new CmdWinWinSetMode(win.Sdl2Window, _clyde._windowMode));
-        }
-
-        private static void WinThreadWinSetMode(CmdWinWinSetMode cmd)
-        {
-            var flags = cmd.Mode switch
-            {
-                WindowMode.Fullscreen => (uint) SDL_WINDOW_FULLSCREEN_DESKTOP,
-                _ => 0u
-            };
-
-            SDL_SetWindowFullscreen(cmd.Window, flags);
-        }
-
-        public void WindowSetTitle(WindowReg window, string title)
-        {
-            SendCmd(new CmdWinSetTitle(WinPtr(window), title));
-        }
-
-        private static void WinThreadWinSetTitle(CmdWinSetTitle cmd)
-        {
-            SDL_SetWindowTitle(cmd.Window, cmd.Title);
-        }
-
-        public void WindowSetMonitor(WindowReg window, IClydeMonitor monitor)
-        {
-            // API isn't really used and kinda wack, don't feel like figuring it out for SDL2 yet.
-            _sawmill.Warning("WindowSetMonitor not implemented on SDL2");
-        }
-
-        public void WindowSetSize(WindowReg window, Vector2i size)
-        {
-            SendCmd(new CmdWinSetSize(WinPtr(window), size.X, size.Y));
-        }
-
-        public void WindowSetVisible(WindowReg window, bool visible)
-        {
-            window.IsVisible = visible;
-            SendCmd(new CmdWinSetVisible(WinPtr(window), visible));
-        }
-
-        private static void WinThreadWinSetSize(CmdWinSetSize cmd)
-        {
-            SDL_SetWindowSize(cmd.Window, cmd.W, cmd.H);
-        }
-
-        private static void WinThreadWinSetVisible(CmdWinSetVisible cmd)
-        {
-            if (cmd.Visible)
-                SDL_ShowWindow(cmd.Window);
-            else
-                SDL_HideWindow(cmd.Window);
-        }
-
-        public void WindowRequestAttention(WindowReg window)
-        {
-            SendCmd(new CmdWinRequestAttention(WinPtr(window)));
-        }
-
-        private void WinThreadWinRequestAttention(CmdWinRequestAttention cmd)
-        {
-            var res = SDL_FlashWindow(cmd.Window, SDL_FLASH_UNTIL_FOCUSED);
-            if (res < 0)
-                _sawmill.Error("Failed to flash window: {error}", SDL_GetError());
-        }
-
-        public unsafe void WindowSwapBuffers(WindowReg window)
-        {
-            var reg = (Sdl2WindowReg)window;
-            var windowPtr = WinPtr(reg);
-
-            // On Windows, SwapBuffers does not correctly sync to the DWM compositor.
-            // This means OpenGL vsync is effectively broken by default on Windows.
-            // We manually sync via DwmFlush(). GLFW does this automatically, SDL2 does not.
-            //
-            // Windows DwmFlush logic partly taken from:
-            // https://github.com/love2d/love/blob/5175b0d1b599ea4c7b929f6b4282dd379fa116b8/src/modules/window/sdl/Window.cpp#L1018
-            // https://github.com/glfw/glfw/blob/d3ede7b6847b66cf30b067214b2b4b126d4c729b/src/wgl_context.c#L321-L340
-            // See also: https://github.com/libsdl-org/SDL/issues/5797
-
-            var dwmFlush = false;
-            var swapInterval = 0;
-
-            if (OperatingSystem.IsWindows() && !reg.Fullscreen && reg.SwapInterval > 0)
-            {
-                BOOL compositing;
-                // 6.2 is Windows 8
-                // https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/wdm/ns-wdm-_osversioninfoexw
-                if (OperatingSystem.IsWindowsVersionAtLeast(6, 2)
-                    || Windows.SUCCEEDED(Windows.DwmIsCompositionEnabled(&compositing)) && compositing)
-                {
-                    var curCtx = SDL_GL_GetCurrentContext();
-                    var curWin = SDL_GL_GetCurrentWindow();
-
-                    if (curCtx != reg.GlContext || curWin != reg.Sdl2Window)
-                        throw new InvalidOperationException("Window context must be current!");
-
-                    SDL_GL_SetSwapInterval(0);
-                    dwmFlush = true;
-                    swapInterval = reg.SwapInterval;
-                }
-            }
-
-            SDL_GL_SwapWindow(windowPtr);
-
-            if (dwmFlush)
-            {
-                var i = swapInterval;
-                while (i-- > 0)
-                {
-                    Windows.DwmFlush();
-                }
-
-                SDL_GL_SetSwapInterval(swapInterval);
-            }
-        }
-
-        public uint? WindowGetX11Id(WindowReg window)
-        {
-            CheckWindowDisposed(window);
-
-            var reg = (Sdl2WindowReg) window;
-
-            if (reg.SysWMinfo.subsystem != SDL_SYSWM_X11)
-                return null;
-
-            return (uint?) reg.SysWMinfo.info.x11.window;
-        }
-
-        public nint? WindowGetX11Display(WindowReg window)
-        {
-            CheckWindowDisposed(window);
-
-            var reg = (Sdl2WindowReg) window;
-
-            if (reg.SysWMinfo.subsystem != SDL_SYSWM_X11)
-                return null;
-
-            return reg.SysWMinfo.info.x11.display;
-        }
-
-        public nint? WindowGetWin32Window(WindowReg window)
-        {
-            CheckWindowDisposed(window);
-
-            var reg = (Sdl2WindowReg) window;
-
-            if (reg.SysWMinfo.subsystem != SDL_SYSWM_WINDOWS)
-                return null;
-
-            return reg.SysWMinfo.info.win.window;
-        }
-
-        public void RunOnWindowThread(Action a)
-        {
-            SendCmd(new CmdRunAction(a));
-        }
-
-        public void TextInputSetRect(UIBox2i rect)
-        {
-            SendCmd(new CmdTextInputSetRect(new SDL_Rect
-            {
-                x = rect.Left,
-                y = rect.Top,
-                w = rect.Width,
-                h = rect.Height
-            }));
-        }
-
-        private static void WinThreadSetTextInputRect(CmdTextInputSetRect cmdTextInput)
-        {
-            var rect = cmdTextInput.Rect;
-            SDL_SetTextInputRect(ref rect);
-        }
-
-        public void TextInputStart()
-        {
-            SendCmd(CmdTextInputStart.Instance);
-        }
-
-        private static void WinThreadStartTextInput()
-        {
-            SDL_StartTextInput();
-        }
-
-        public void TextInputStop()
-        {
-            SendCmd(CmdTextInputStop.Instance);
-        }
-
-        private static void WinThreadStopTextInput()
-        {
-            SDL_StopTextInput();
-        }
-
-        public void ClipboardSetText(WindowReg mainWindow, string text)
-        {
-            SendCmd(new CmdSetClipboard(text));
-        }
-
-        private void WinThreadSetClipboard(CmdSetClipboard cmd)
-        {
-            var res = SDL_SetClipboardText(cmd.Text);
-            if (res < 0)
-                _sawmill.Error("Failed to set clipboard text: {error}", SDL_GetError());
-        }
-
-        public Task<string> ClipboardGetText(WindowReg mainWindow)
-        {
-            var tcs = new TaskCompletionSource<string>();
-            SendCmd(new CmdGetClipboard(tcs));
-            return tcs.Task;
-        }
-
-        private static void WinThreadGetClipboard(CmdGetClipboard cmd)
-        {
-            cmd.Tcs.TrySetResult(SDL_GetClipboardText());
-        }
-
-        private static Vector2 GetWindowScale(nint window)
-        {
-            // Get scale by diving size in pixels with size in points.
-            SDL_GetWindowSizeInPixels(window, out var pixW, out var pixH);
-            SDL_GetWindowSize(window, out var pointW, out var pointH);
-
-            // Avoiding degenerate cases, not sure if these can actually happen.
-            if (pixW == 0 || pixH == 0 || pointW == 0 || pointH == 0)
-                return new Vector2(1, 1);
-
-            var scaleH = pixW / (float) pointW;
-            var scaleV = pixH / (float) pointH;
-
-            // Round to 5% increments to avoid rounding errors causing constantly different scales.
-            scaleH = MathF.Round(scaleH * 20) / 20;
-            scaleV = MathF.Round(scaleV * 20) / 20;
-
-            return new Vector2(scaleH, scaleV);
-        }
-
-        private static void CheckWindowDisposed(WindowReg reg)
-        {
-            if (reg.IsDisposed)
-                throw new ObjectDisposedException("Window disposed");
-        }
-
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private static nint WinPtr(WindowReg reg) => ((Sdl2WindowReg)reg).Sdl2Window;
-
-        private WindowReg? FindWindow(uint windowId)
-        {
-            foreach (var windowReg in _clyde._windows)
-            {
-                var glfwReg = (Sdl2WindowReg) windowReg;
-                if (glfwReg.WindowId == windowId)
-                    return windowReg;
-            }
-
-            return null;
-        }
-
-
-        private sealed class Sdl2WindowReg : WindowReg
-        {
-            public nint Sdl2Window;
-            public uint WindowId;
-            public nint GlContext;
-            public SDL_SysWMinfo SysWMinfo;
-#pragma warning disable CS0649
-            public bool Fullscreen;
-#pragma warning restore CS0649
-            public int SwapInterval;
-
-            // Kept around to avoid it being GCd.
-            public CursorImpl? Cursor;
-        }
-
-    }
-}

Robust.Client/Graphics/Clyde/Windowing/Sdl2.cs

@@ -1,190 +0,0 @@
-using System;
-using System.Runtime.CompilerServices;
-using System.Runtime.InteropServices;
-using Robust.Shared.Configuration;
-using Robust.Shared.IoC;
-using Robust.Shared.Log;
-using static SDL2.SDL;
-using static SDL2.SDL.SDL_LogCategory;
-using DependencyAttribute = Robust.Shared.IoC.DependencyAttribute;
-
-namespace Robust.Client.Graphics.Clyde;
-
-internal partial class Clyde
-{
-    private sealed partial class Sdl2WindowingImpl : IWindowingImpl
-    {
-        [Dependency] private readonly ILogManager _logManager = default!;
-        [Dependency] private readonly IConfigurationManager _cfg = default!;
-
-        private readonly Clyde _clyde;
-        private GCHandle _selfGCHandle;
-
-        private readonly ISawmill _sawmill;
-        private readonly ISawmill _sawmillSdl2;
-
-        public Sdl2WindowingImpl(Clyde clyde, IDependencyCollection deps)
-        {
-            _clyde = clyde;
-            deps.InjectDependencies(this, true);
-
-            _sawmill = _logManager.GetSawmill("clyde.win");
-            _sawmillSdl2 = _logManager.GetSawmill("clyde.win.sdl2");
-        }
-
-        public bool Init()
-        {
-            InitChannels();
-
-            if (!InitSdl2())
-                return false;
-
-            return true;
-        }
-
-        private unsafe bool InitSdl2()
-        {
-            _selfGCHandle = GCHandle.Alloc(this, GCHandleType.Normal);
-
-            SDL_LogSetAllPriority(SDL_LogPriority.SDL_LOG_PRIORITY_VERBOSE);
-            SDL_LogSetOutputFunction(&LogOutputFunction, (void*) GCHandle.ToIntPtr(_selfGCHandle));
-
-            SDL_SetHint("SDL_WINDOWS_DPI_SCALING", "1");
-            SDL_SetHint(SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, "1");
-            SDL_SetHint(SDL_HINT_IME_SUPPORT_EXTENDED_TEXT, "1");
-            SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");
-
-            var res = SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS);
-            if (res < 0)
-            {
-                _sawmill.Fatal("Failed to initialize SDL2: {error}", SDL_GetError());
-                return false;
-            }
-
-            SDL_GetVersion(out var version);
-            var videoDriver = SDL_GetCurrentVideoDriver();
-            _sawmill.Debug(
-                "SDL2 initialized, version: {major}.{minor}.{patch}, video driver: {videoDriver}", version.major, version.minor, version.patch, videoDriver);
-
-            _sdlEventWakeup = SDL_RegisterEvents(1);
-
-            SDL_EventState(SDL_EventType.SDL_SYSWMEVENT, SDL_ENABLE);
-
-            InitCursors();
-            InitMonitors();
-            ReloadKeyMap();
-
-            SDL_AddEventWatch(&EventWatch, (void*) GCHandle.ToIntPtr(_selfGCHandle));
-
-            // SDL defaults to having text input enabled, so we have to manually turn it off in init for consistency.
-            // If we don't, text input will remain enabled *until* the user first leaves a LineEdit/TextEdit.
-            SDL_StopTextInput();
-
-            return true;
-        }
-
-        public unsafe void Shutdown()
-        {
-            if (_selfGCHandle != default)
-            {
-                SDL_DelEventWatch(&EventWatch, (void*) GCHandle.ToIntPtr(_selfGCHandle));
-                _selfGCHandle.Free();
-            }
-
-            SDL_LogSetOutputFunction(null, null);
-
-            if (SDL_WasInit(0) != 0)
-            {
-                _sawmill.Debug("Terminating SDL2");
-                SDL_Quit();
-            }
-        }
-
-        public void FlushDispose()
-        {
-            // Not currently used
-        }
-
-        public void GLMakeContextCurrent(WindowReg? reg)
-        {
-            int res;
-            if (reg is Sdl2WindowReg sdlReg)
-                res = SDL_GL_MakeCurrent(sdlReg.Sdl2Window, sdlReg.GlContext);
-            else
-                res = SDL_GL_MakeCurrent(IntPtr.Zero, IntPtr.Zero);
-
-            if (res < 0)
-                _sawmill.Error("SDL_GL_MakeCurrent failed: {error}", SDL_GetError());
-        }
-
-        public void GLSwapInterval(WindowReg reg, int interval)
-        {
-            ((Sdl2WindowReg)reg).SwapInterval = interval;
-            SDL_GL_SetSwapInterval(interval);
-        }
-
-        public unsafe void* GLGetProcAddress(string procName)
-        {
-            return (void*) SDL_GL_GetProcAddress(procName);
-        }
-
-        public string GetDescription()
-        {
-            SDL_GetVersion(out var version);
-            _sawmill.Debug(
-                "SDL2 initialized, version: {major}.{minor}.{patch}", version.major, version.minor, version.patch);
-
-            var videoDriver = SDL_GetCurrentVideoDriver();
-
-            return $"SDL2 {version.major}.{version.minor}.{version.patch} ({videoDriver})";
-        }
-
-        [UnmanagedCallersOnly(CallConvs = new []{typeof(CallConvCdecl)})]
-        private static unsafe void LogOutputFunction(
-            void* userdata,
-            int category,
-            SDL_LogPriority priority,
-            byte* message)
-        {
-            var obj = (Sdl2WindowingImpl) GCHandle.FromIntPtr((IntPtr)userdata).Target!;
-
-            var level = priority switch
-            {
-                SDL_LogPriority.SDL_LOG_PRIORITY_VERBOSE => LogLevel.Verbose,
-                SDL_LogPriority.SDL_LOG_PRIORITY_DEBUG => LogLevel.Debug,
-                SDL_LogPriority.SDL_LOG_PRIORITY_INFO => LogLevel.Info,
-                SDL_LogPriority.SDL_LOG_PRIORITY_WARN => LogLevel.Warning,
-                SDL_LogPriority.SDL_LOG_PRIORITY_ERROR => LogLevel.Error,
-                SDL_LogPriority.SDL_LOG_PRIORITY_CRITICAL => LogLevel.Fatal,
-                _ => LogLevel.Error
-            };
-
-            var msg = Marshal.PtrToStringUTF8((IntPtr) message) ?? "";
-            if (msg == "That operation is not supported")
-            {
-                obj._sawmillSdl2.Info(Environment.StackTrace);
-            }
-            
-            var categoryName = SdlLogCategoryName(category);
-            obj._sawmillSdl2.Log(level, $"[{categoryName}] {msg}");
-        }
-
-        private static string SdlLogCategoryName(int category)
-        {
-            return (SDL_LogCategory) category switch {
-                // @formatter:off
-                SDL_LOG_CATEGORY_APPLICATION => "application",
-                SDL_LOG_CATEGORY_ERROR       => "error",
-                SDL_LOG_CATEGORY_ASSERT      => "assert",
-                SDL_LOG_CATEGORY_SYSTEM      => "system",
-                SDL_LOG_CATEGORY_AUDIO       => "audio",
-                SDL_LOG_CATEGORY_VIDEO       => "video",
-                SDL_LOG_CATEGORY_RENDER      => "render",
-                SDL_LOG_CATEGORY_INPUT       => "input",
-                SDL_LOG_CATEGORY_TEST        => "test",
-                _                            => "unknown"
-                // @formatter:on
-            };
-        }
-    }
-}

Robust.Client/Graphics/Clyde/Windowing/Sdl3.Cursor.cs

@@ -3,16 +3,15 @@ using System.Collections.Generic;
 using Robust.Client.Utility;
 using Robust.Shared.Maths;
 using Robust.Shared.Utility;
+using SDL3;
 using SixLabors.ImageSharp;
 using SixLabors.ImageSharp.PixelFormats;
-using static SDL2.SDL;
-using static SDL2.SDL.SDL_SystemCursor;
 
 namespace Robust.Client.Graphics.Clyde;
 
 internal partial class Clyde
 {
-    private sealed partial class Sdl2WindowingImpl : IWindowingImpl
+    private sealed partial class Sdl3WindowingImpl
     {
         private readonly Dictionary<ClydeHandle, WinThreadCursorReg> _winThreadCursors = new();
         private readonly CursorImpl[] _standardCursors = new CursorImpl[(int)StandardCursorShape.CountCursors];
@@ -28,31 +27,32 @@ internal partial class Clyde
             image.GetPixelSpan().CopyTo(cloneImg.GetPixelSpan());
 
             var id = _clyde.AllocRid();
-            SendCmd(new CmdCursorCreate(cloneImg, hotSpot, id));
+            SendCmd(new CmdCursorCreate { Bytes = cloneImg, Hotspot = hotSpot, Cursor = id });
 
             return new CursorImpl(this, id, false);
         }
 
         private unsafe void WinThreadCursorCreate(CmdCursorCreate cmd)
         {
-            var (img, (hotX, hotY), id) = cmd;
+            using var img = cmd.Bytes;
 
             fixed (Rgba32* pixPtr = img.GetPixelSpan())
             {
-                var surface = SDL_CreateRGBSurfaceWithFormatFrom(
+                var surface = SDL.SDL_CreateSurfaceFrom(
+                    img.Width,
+                    img.Height,
+                    SDL.SDL_PixelFormat.SDL_PIXELFORMAT_ABGR8888,
                     (IntPtr)pixPtr,
-                    img.Width, img.Height, 0,
-                    sizeof(Rgba32) * img.Width,
-                    SDL_PIXELFORMAT_RGBA8888);
+                    sizeof(Rgba32) * img.Width);
 
-                var cursor = SDL_CreateColorCursor(surface, hotX, hotY);
+                var cursor = SDL.SDL_CreateColorCursor(surface, cmd.Hotspot.X, cmd.Hotspot.Y);
+                if (cursor == 0)
+                    throw new InvalidOperationException("SDL_CreateColorCursor failed");
 
-                _winThreadCursors.Add(id, new WinThreadCursorReg { Ptr = cursor });
+                _winThreadCursors.Add(cmd.Cursor, new WinThreadCursorReg { Ptr = cursor });
 
-                SDL_FreeSurface(surface);
+                SDL.SDL_DestroySurface(surface);
             }
-
-            img.Dispose();
         }
 
         public void CursorSet(WindowReg window, ICursor? cursor)
@@ -62,7 +62,7 @@ internal partial class Clyde
             // SDL_SetCursor(NULL) does redraw, not reset.
             cursor ??= CursorGetStandard(StandardCursorShape.Arrow);
 
-            var reg = (Sdl2WindowReg)window;
+            var reg = (Sdl3WindowReg)window;
 
             if (reg.Cursor == cursor)
                 return;
@@ -74,7 +74,7 @@ internal partial class Clyde
                 throw new ObjectDisposedException(nameof(cursor));
 
             reg.Cursor = impl;
-            SendCmd(new CmdWinCursorSet(reg.Sdl2Window, impl.Id));
+            SendCmd(new CmdWinCursorSet { Window = reg.Sdl3Window, Cursor = impl.Id });
         }
 
         private void WinThreadWinCursorSet(CmdWinCursorSet cmd)
@@ -83,22 +83,22 @@ internal partial class Clyde
             var ptr = _winThreadCursors[cmd.Cursor].Ptr;
 
             // TODO: multi-window??
-            SDL_SetCursor(ptr);
+            SDL.SDL_SetCursor(ptr);
         }
 
         private void InitCursors()
         {
-            Add(StandardCursorShape.Arrow, SDL_SYSTEM_CURSOR_ARROW);
-            Add(StandardCursorShape.IBeam, SDL_SYSTEM_CURSOR_IBEAM);
-            Add(StandardCursorShape.Crosshair, SDL_SYSTEM_CURSOR_CROSSHAIR);
-            Add(StandardCursorShape.Hand, SDL_SYSTEM_CURSOR_HAND);
-            Add(StandardCursorShape.HResize, SDL_SYSTEM_CURSOR_SIZEWE);
-            Add(StandardCursorShape.VResize, SDL_SYSTEM_CURSOR_SIZENS);
+            Add(StandardCursorShape.Arrow, SDL.SDL_SystemCursor.SDL_SYSTEM_CURSOR_DEFAULT);
+            Add(StandardCursorShape.IBeam, SDL.SDL_SystemCursor.SDL_SYSTEM_CURSOR_TEXT);
+            Add(StandardCursorShape.Crosshair, SDL.SDL_SystemCursor.SDL_SYSTEM_CURSOR_CROSSHAIR);
+            Add(StandardCursorShape.Hand, SDL.SDL_SystemCursor.SDL_SYSTEM_CURSOR_POINTER);
+            Add(StandardCursorShape.HResize, SDL.SDL_SystemCursor.SDL_SYSTEM_CURSOR_EW_RESIZE);
+            Add(StandardCursorShape.VResize, SDL.SDL_SystemCursor.SDL_SYSTEM_CURSOR_NS_RESIZE);
 
-            void Add(StandardCursorShape shape, SDL_SystemCursor sysCursor)
+            void Add(StandardCursorShape shape, SDL.SDL_SystemCursor sysCursor)
             {
                 var id = _clyde.AllocRid();
-                var cursor = SDL_CreateSystemCursor(sysCursor);
+                var cursor = SDL.SDL_CreateSystemCursor(sysCursor);
 
                 var impl = new CursorImpl(this, id, true);
 
@@ -107,13 +107,21 @@ internal partial class Clyde
             }
         }
 
+        private void WinThreadCursorDestroy(CmdCursorDestroy cmd)
+        {
+            if (!_winThreadCursors.TryGetValue(cmd.Cursor, out var cursor))
+                return;
+
+            SDL.SDL_DestroyCursor(cursor.Ptr);
+        }
+
         private sealed class CursorImpl : ICursor
         {
             private readonly bool _standard;
-            public Sdl2WindowingImpl Owner { get; }
+            public Sdl3WindowingImpl Owner { get; }
             public ClydeHandle Id { get; private set; }
 
-            public CursorImpl(Sdl2WindowingImpl clyde, ClydeHandle id, bool standard)
+            public CursorImpl(Sdl3WindowingImpl clyde, ClydeHandle id, bool standard)
             {
                 _standard = standard;
                 Owner = clyde;
@@ -127,7 +135,7 @@ internal partial class Clyde
 
             private void DisposeImpl()
             {
-                Owner.SendCmd(new CmdCursorDestroy(Id));
+                Owner.SendCmd(new CmdCursorDestroy { Cursor = Id });
                 Id = default;
             }
 
@@ -147,9 +155,5 @@ internal partial class Clyde
         {
             public nint Ptr;
         }
-
-        private void WinThreadCursorDestroy(CmdCursorDestroy cmd)
-        {
-        }
     }
 }

Robust.Client/Graphics/Clyde/Windowing/Sdl3.Event.cs

@@ -2,18 +2,16 @@
 using System.Numerics;
 using Robust.Client.Input;
 using Robust.Shared.Map;
-using TerraFX.Interop.Windows;
-using static SDL2.SDL;
-using static SDL2.SDL.SDL_EventType;
-using static SDL2.SDL.SDL_Keymod;
-using static SDL2.SDL.SDL_WindowEventID;
+using SDL3;
 using Key = Robust.Client.Input.Keyboard.Key;
+using ET = SDL3.SDL.SDL_EventType;
+using SDL_Keymod = SDL3.SDL.SDL_Keymod;
 
 namespace Robust.Client.Graphics.Clyde;
 
 internal partial class Clyde
 {
-    private sealed partial class Sdl2WindowingImpl
+    private sealed partial class Sdl3WindowingImpl
     {
         public void ProcessEvents(bool single = false)
         {
@@ -47,15 +45,18 @@ internal partial class Clyde
                 case EventWindowCreate wCreate:
                     FinishWindowCreate(wCreate);
                     break;
-                case EventWindow ev:
-                    ProcessEventWindow(ev);
+                case EventWindowMisc ev:
+                    ProcessEventWindowMisc(ev);
                     break;
                 case EventKey ev:
                     ProcessEventKey(ev);
                     break;
-                case EventWindowSize ev:
+                case EventWindowPixelSize ev:
                     ProcessEventWindowSize(ev);
                     break;
+                case EventWindowContentScale ev:
+                    ProcessEventWindowContentScale(ev);
+                    break;
                 case EventText ev:
                     ProcessEventText(ev);
                     break;
@@ -74,9 +75,6 @@ internal partial class Clyde
                 case EventMonitorSetup ev:
                     ProcessSetupMonitor(ev);
                     break;
-                case EventWindowsFakeV ev:
-                    ProcessWindowsFakeV(ev);
-                    break;
                 case EventKeyMapChanged:
                     ProcessKeyMapChanged();
                     break;
@@ -84,7 +82,7 @@ internal partial class Clyde
                     ProcessEventQuit();
                     break;
                 default:
-                    _sawmill.Error($"Unknown SDL2 event type: {evb.GetType().Name}");
+                    _sawmill.Error($"Unknown SDL3 event type: {evb.GetType().Name}");
                     break;
             }
         }
@@ -96,7 +94,7 @@ internal partial class Clyde
             _clyde.SendCloseWindow(window, new WindowRequestClosedEventArgs(window.Handle));
         }
 
-        private void ProcessEventWindow(EventWindow ev)
+        private void ProcessEventWindowMisc(EventWindowMisc ev)
         {
             var window = FindWindow(ev.WindowId);
             if (window == null)
@@ -104,33 +102,38 @@ internal partial class Clyde
 
             switch (ev.EventId)
             {
-                case SDL_WINDOWEVENT_CLOSE:
+                case ET.SDL_EVENT_WINDOW_CLOSE_REQUESTED:
                     _clyde.SendCloseWindow(window, new WindowRequestClosedEventArgs(window.Handle));
                     break;
-                case SDL_WINDOWEVENT_ENTER:
+                case ET.SDL_EVENT_WINDOW_MOUSE_ENTER:
                     _clyde._currentHoveredWindow = window;
                     _clyde.SendMouseEnterLeave(new MouseEnterLeaveEventArgs(window.Handle, true));
                     break;
-                case SDL_WINDOWEVENT_LEAVE:
+                case ET.SDL_EVENT_WINDOW_MOUSE_LEAVE:
                     if (_clyde._currentHoveredWindow == window)
                         _clyde._currentHoveredWindow = null;
 
                     _clyde.SendMouseEnterLeave(new MouseEnterLeaveEventArgs(window.Handle, false));
                     break;
-                case SDL_WINDOWEVENT_MINIMIZED:
+                case ET.SDL_EVENT_WINDOW_MINIMIZED:
                     window.IsMinimized = true;
                     break;
-                case SDL_WINDOWEVENT_RESTORED:
+                case ET.SDL_EVENT_WINDOW_RESTORED:
                     window.IsMinimized = false;
                     break;
-                case SDL_WINDOWEVENT_FOCUS_GAINED:
+                case ET.SDL_EVENT_WINDOW_FOCUS_GAINED:
                     window.IsFocused = true;
                     _clyde.SendWindowFocus(new WindowFocusedEventArgs(true, window.Handle));
                     break;
-                case SDL_WINDOWEVENT_FOCUS_LOST:
+                case ET.SDL_EVENT_WINDOW_FOCUS_LOST:
                     window.IsFocused = false;
                     _clyde.SendWindowFocus(new WindowFocusedEventArgs(false, window.Handle));
                     break;
+                case ET.SDL_EVENT_WINDOW_MOVED:
+                    window.WindowPos = (ev.Data1, ev.Data2);
+                    break;
+                default:
+                    throw new ArgumentOutOfRangeException();
             }
         }
 
@@ -153,10 +156,9 @@ internal partial class Clyde
             if (windowReg == null)
                 return;
 
-            var mods = SDL_GetModState();
-            var button = ConvertSdl2Button(ev.Button);
+            var button = ConvertSdl3Button(ev.Button);
             var key = Mouse.MouseButtonToKey(button);
-            EmitKeyEvent(key, ev.Type, false, mods, 0);
+            EmitKeyEvent(key, ev.Type, false, ev.Mods, 0);
         }
 
         private void ProcessEventMouseMotion(EventMouseMotion ev)
@@ -166,8 +168,7 @@ internal partial class Clyde
                 return;
 
             var newPos = new Vector2(ev.X, ev.Y) * windowReg.PixelRatio;
-            // SDL2 does give us delta positions, but I'm worried about rounding errors thanks to DPI stuff.
-            var delta = newPos - windowReg.LastMousePos;
+            var delta = new Vector2(ev.XRel, ev.YRel);
             windowReg.LastMousePos = newPos;
 
             _clyde._currentHoveredWindow = windowReg;
@@ -185,7 +186,7 @@ internal partial class Clyde
             _clyde.SendTextEditing(new TextEditingEventArgs(ev.Text, ev.Start, ev.Length));
         }
 
-        private void ProcessEventWindowSize(EventWindowSize ev)
+        private void ProcessEventWindowSize(EventWindowPixelSize ev)
         {
             var window = ev.WindowId;
             var width = ev.Width;
@@ -205,28 +206,31 @@ internal partial class Clyde
                 return;
 
             windowReg.PixelRatio = windowReg.FramebufferSize / (Vector2)windowReg.WindowSize;
-            var newScale = new Vector2(ev.XScale, ev.YScale);
-
-            if (!windowReg.WindowScale.Equals(newScale))
-            {
-                windowReg.WindowScale = newScale;
-                _clyde.SendWindowContentScaleChanged(new WindowContentScaleEventArgs(windowReg.Handle));
-            }
 
             _clyde.SendWindowResized(windowReg, oldSize);
         }
 
-        private void ProcessEventKey(EventKey ev)
+        private void ProcessEventWindowContentScale(EventWindowContentScale ev)
         {
-            EmitKeyEvent(ConvertSdl2Scancode(ev.Scancode), ev.Type, ev.Repeat, ev.Mods, ev.Scancode);
+            var windowReg = FindWindow(ev.WindowId);
+            if (windowReg == null)
+                return;
+
+            windowReg.WindowScale = new Vector2(ev.Scale, ev.Scale);
+            _clyde.SendWindowContentScaleChanged(new WindowContentScaleEventArgs(windowReg.Handle));
         }
 
-        private void EmitKeyEvent(Key key, SDL_EventType type, bool repeat, SDL_Keymod mods, SDL_Scancode scancode)
+        private void ProcessEventKey(EventKey ev)
         {
-            var shift = (mods & KMOD_SHIFT) != 0;
-            var alt = (mods & KMOD_ALT) != 0;
-            var control = (mods & KMOD_CTRL) != 0;
-            var system = (mods & KMOD_GUI) != 0;
+            EmitKeyEvent(ConvertSdl3Scancode(ev.Scancode), ev.Type, ev.Repeat, ev.Mods, ev.Scancode);
+        }
+
+        private void EmitKeyEvent(Key key, ET type, bool repeat, SDL.SDL_Keymod mods, SDL.SDL_Scancode scancode)
+        {
+            var shift = (mods & SDL_Keymod.SDL_KMOD_SHIFT) != 0;
+            var alt = (mods & SDL_Keymod.SDL_KMOD_ALT) != 0;
+            var control = (mods & SDL_Keymod.SDL_KMOD_CTRL) != 0;
+            var system = (mods & SDL_Keymod.SDL_KMOD_GUI) != 0;
 
             var ev = new KeyEventArgs(
                 key,
@@ -236,36 +240,17 @@ internal partial class Clyde
 
             switch (type)
             {
-                case SDL_KEYUP:
-                case SDL_MOUSEBUTTONUP:
+                case ET.SDL_EVENT_KEY_UP:
+                case ET.SDL_EVENT_MOUSE_BUTTON_UP:
                     _clyde.SendKeyUp(ev);
                     break;
-                case SDL_KEYDOWN:
-                case SDL_MOUSEBUTTONDOWN:
+                case ET.SDL_EVENT_KEY_DOWN:
+                case ET.SDL_EVENT_MOUSE_BUTTON_DOWN:
                     _clyde.SendKeyDown(ev);
                     break;
             }
         }
 
-        private void ProcessWindowsFakeV(EventWindowsFakeV ev)
-        {
-            var type = (int)ev.Message switch
-            {
-                WM.WM_KEYUP => SDL_KEYUP,
-                WM.WM_KEYDOWN => SDL_KEYDOWN,
-                _ => throw new ArgumentOutOfRangeException()
-            };
-
-            var key = (int)ev.WParam switch
-            {
-                0x56 /* V */ => Key.V,
-                VK.VK_CONTROL => Key.Control,
-                _ => throw new ArgumentOutOfRangeException()
-            };
-
-            EmitKeyEvent(key, type, false, 0, 0);
-        }
-
         private void ProcessKeyMapChanged()
         {
             _clyde.SendInputModeChanged();

Robust.Client/Graphics/Clyde/Windowing/Sdl3.FileDialog.cs

@@ -0,0 +1,145 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using System.Text;
+using System.Threading.Tasks;
+using Robust.Client.UserInterface;
+using SDL3;
+
+namespace Robust.Client.Graphics.Clyde;
+
+internal partial class Clyde
+{
+    private sealed partial class Sdl3WindowingImpl : IFileDialogManager
+    {
+        public async Task<Stream?> OpenFile(FileDialogFilters? filters = null)
+        {
+            var fileName = await ShowFileDialogOfType(SDL.SDL_FILEDIALOG_OPENFILE, filters);
+            if (fileName == null)
+                return null;
+
+            return File.OpenRead(fileName);
+        }
+
+        public async Task<(Stream fileStream, bool alreadyExisted)?> SaveFile(FileDialogFilters? filters = null, bool truncate = true)
+        {
+            var fileName = await ShowFileDialogOfType(SDL.SDL_FILEDIALOG_SAVEFILE, filters);
+            if (fileName == null)
+                return null;
+
+            try
+            {
+                return (File.Open(fileName, truncate ? FileMode.Truncate : FileMode.Open), true);
+            }
+            catch (FileNotFoundException)
+            {
+                return (File.Open(fileName, FileMode.Create), false);
+            }
+        }
+
+        private unsafe Task<string?> ShowFileDialogOfType(int type, FileDialogFilters? filters)
+        {
+            var props = SDL.SDL_CreateProperties();
+
+            SDL.SDL_DialogFileFilter* filtersAlloc = null;
+            if (filters != null)
+            {
+                filtersAlloc = (SDL.SDL_DialogFileFilter*)NativeMemory.Alloc(
+                    (UIntPtr)filters.Groups.Count,
+                    (UIntPtr)sizeof(SDL.SDL_DialogFileFilter));
+
+                SDL.SDL_SetNumberProperty(props, SDL.SDL_PROP_FILE_DIALOG_NFILTERS_NUMBER, filters.Groups.Count);
+                SDL.SDL_SetPointerProperty(props, SDL.SDL_PROP_FILE_DIALOG_FILTERS_POINTER, (nint)filtersAlloc);
+
+                // All these mallocs aren't gonna win any performance awards, but oh well.
+                for (var i = 0; i < filters.Groups.Count; i++)
+                {
+                    var (name, pattern) = ConvertFilterGroup(filters.Groups[i]);
+                    filtersAlloc[i].name = StringToNative(name);
+                    filtersAlloc[i].pattern = StringToNative(pattern);
+                }
+            }
+
+            var task = ShowFileDialogWithProperties(type, props);
+
+            SDL.SDL_DestroyProperties(props);
+
+            if (filtersAlloc != null)
+            {
+                for (var i = 0; i < filters!.Groups.Count; i++)
+                {
+                    var filter = filtersAlloc[i];
+                    NativeMemory.Free(filter.name);
+                    NativeMemory.Free(filter.pattern);
+                }
+            }
+
+            return task;
+        }
+
+        private static unsafe byte* StringToNative(string str)
+        {
+            var byteCount = Encoding.UTF8.GetByteCount(str);
+
+            var mem = (byte*) NativeMemory.Alloc((nuint)(byteCount + 1));
+            Encoding.UTF8.GetBytes(str, new Span<byte>(mem, byteCount));
+            mem[byteCount] = 0; // null-terminate
+
+            return mem;
+        }
+
+        private (string name, string pattern) ConvertFilterGroup(FileDialogFilters.Group group)
+        {
+            var name = string.Join(", ", group.Extensions.Select(e => $"*.{e}"));
+            var pattern = string.Join(";", group.Extensions);
+            return (name, pattern);
+        }
+
+        private unsafe Task<string?> ShowFileDialogWithProperties(int type, uint properties)
+        {
+            var tcs = new TaskCompletionSource<string?>();
+
+            var gcHandle = GCHandle.Alloc(new FileDialogState
+            {
+                Parent = this,
+                Tcs = tcs
+            });
+
+            SDL.SDL_ShowFileDialogWithProperties(
+                type,
+                &FileDialogCallback,
+                (void*)GCHandle.ToIntPtr(gcHandle),
+                properties);
+
+            return tcs.Task;
+        }
+
+        [UnmanagedCallersOnly(CallConvs = [typeof(CallConvCdecl)])]
+        private static unsafe void FileDialogCallback(void* userdata, byte** filelist, int filter)
+        {
+            var stateHandle = GCHandle.FromIntPtr((IntPtr)userdata);
+            var state = (FileDialogState)stateHandle.Target!;
+            stateHandle.Free();
+
+            if (filelist == null)
+            {
+                // Error
+                state.Parent._sawmill.Error("File dialog failed: {error}", SDL.SDL_GetError());
+                state.Tcs.SetResult(null);
+                return;
+            }
+
+            // Handles null (cancelled/none selected) transparently.
+            var str = Marshal.PtrToStringUTF8((nint) filelist[0]);
+            state.Tcs.SetResult(str);
+        }
+
+        private sealed class FileDialogState
+        {
+            public required Sdl3WindowingImpl Parent;
+            public required TaskCompletionSource<string?> Tcs;
+        }
+    }
+}

Robust.Client/Graphics/Clyde/Windowing/Sdl3.Key.cs

@@ -0,0 +1,225 @@
+using System.Collections.Frozen;
+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+using SDL3;
+using Key = Robust.Client.Input.Keyboard.Key;
+using Button = Robust.Client.Input.Mouse.Button;
+using SC = SDL3.SDL.SDL_Scancode;
+
+namespace Robust.Client.Graphics.Clyde;
+
+internal partial class Clyde
+{
+    private sealed partial class Sdl3WindowingImpl
+    {
+        // Indices are values of SDL_Scancode
+        private static readonly Key[] KeyMap;
+        private static readonly FrozenDictionary<Key, SC> KeyMapReverse;
+        private static readonly Button[] MouseButtonMap;
+
+        // TODO: to avoid having to ask the windowing thread, key names are cached.
+        private readonly Dictionary<Key, string> _printableKeyNameMap = new();
+
+        private void ReloadKeyMap()
+        {
+            // This may be ran concurrently from the windowing thread.
+            lock (_printableKeyNameMap)
+            {
+                _printableKeyNameMap.Clear();
+
+                // TODO: Validate this is correct in SDL3.
+
+                // List of mappable keys from SDL2's source appears to be:
+                // entries in SDL_default_keymap that aren't an SDLK_ enum reference.
+                // (the actual logic is more nuanced, but it appears to match the above)
+                // Comes out to these two ranges:
+
+                for (var k = SC.SDL_SCANCODE_A; k <= SC.SDL_SCANCODE_0; k++)
+                {
+                    CacheKey(k);
+                }
+
+                for (var k = SC.SDL_SCANCODE_MINUS; k <= SC.SDL_SCANCODE_SLASH; k++)
+                {
+                    CacheKey(k);
+                }
+
+                void CacheKey(SC scancode)
+                {
+                    var rKey = ConvertSdl3Scancode(scancode);
+                    if (rKey == Key.Unknown)
+                        return;
+
+                    // TODO: SDL_GetKeyFromScancode correct?
+                    var name = SDL.SDL_GetKeyName(
+                        SDL.SDL_GetKeyFromScancode(scancode, SDL.SDL_Keymod.SDL_KMOD_NONE, false));
+
+                    if (!string.IsNullOrEmpty(name))
+                        _printableKeyNameMap.Add(rKey, name);
+                }
+            }
+        }
+
+        public string? KeyGetName(Key key)
+        {
+            lock (_printableKeyNameMap)
+            {
+                if (_printableKeyNameMap.TryGetValue(key, out var name))
+                    return name;
+
+                return null;
+            }
+        }
+
+        internal static Key ConvertSdl3Scancode(SC scancode)
+        {
+            return KeyMap[(int) scancode];
+        }
+
+        public static Button ConvertSdl3Button(int button)
+        {
+            return MouseButtonMap[button];
+        }
+
+        static Sdl3WindowingImpl()
+        {
+            MouseButtonMap = new Button[6];
+            MouseButtonMap[SDL.SDL_BUTTON_LEFT] = Button.Left;
+            MouseButtonMap[SDL.SDL_BUTTON_RIGHT] = Button.Right;
+            MouseButtonMap[SDL.SDL_BUTTON_MIDDLE] = Button.Middle;
+            MouseButtonMap[SDL.SDL_BUTTON_X1] = Button.Button4;
+            MouseButtonMap[SDL.SDL_BUTTON_X2] = Button.Button5;
+
+            KeyMap = new Key[(int) SC.SDL_SCANCODE_COUNT];
+            MapKey(SC.SDL_SCANCODE_A, Key.A);
+            MapKey(SC.SDL_SCANCODE_B, Key.B);
+            MapKey(SC.SDL_SCANCODE_C, Key.C);
+            MapKey(SC.SDL_SCANCODE_D, Key.D);
+            MapKey(SC.SDL_SCANCODE_E, Key.E);
+            MapKey(SC.SDL_SCANCODE_F, Key.F);
+            MapKey(SC.SDL_SCANCODE_G, Key.G);
+            MapKey(SC.SDL_SCANCODE_H, Key.H);
+            MapKey(SC.SDL_SCANCODE_I, Key.I);
+            MapKey(SC.SDL_SCANCODE_J, Key.J);
+            MapKey(SC.SDL_SCANCODE_K, Key.K);
+            MapKey(SC.SDL_SCANCODE_L, Key.L);
+            MapKey(SC.SDL_SCANCODE_M, Key.M);
+            MapKey(SC.SDL_SCANCODE_N, Key.N);
+            MapKey(SC.SDL_SCANCODE_O, Key.O);
+            MapKey(SC.SDL_SCANCODE_P, Key.P);
+            MapKey(SC.SDL_SCANCODE_Q, Key.Q);
+            MapKey(SC.SDL_SCANCODE_R, Key.R);
+            MapKey(SC.SDL_SCANCODE_S, Key.S);
+            MapKey(SC.SDL_SCANCODE_T, Key.T);
+            MapKey(SC.SDL_SCANCODE_U, Key.U);
+            MapKey(SC.SDL_SCANCODE_V, Key.V);
+            MapKey(SC.SDL_SCANCODE_W, Key.W);
+            MapKey(SC.SDL_SCANCODE_X, Key.X);
+            MapKey(SC.SDL_SCANCODE_Y, Key.Y);
+            MapKey(SC.SDL_SCANCODE_Z, Key.Z);
+            MapKey(SC.SDL_SCANCODE_0, Key.Num0);
+            MapKey(SC.SDL_SCANCODE_1, Key.Num1);
+            MapKey(SC.SDL_SCANCODE_2, Key.Num2);
+            MapKey(SC.SDL_SCANCODE_3, Key.Num3);
+            MapKey(SC.SDL_SCANCODE_4, Key.Num4);
+            MapKey(SC.SDL_SCANCODE_5, Key.Num5);
+            MapKey(SC.SDL_SCANCODE_6, Key.Num6);
+            MapKey(SC.SDL_SCANCODE_7, Key.Num7);
+            MapKey(SC.SDL_SCANCODE_8, Key.Num8);
+            MapKey(SC.SDL_SCANCODE_9, Key.Num9);
+            MapKey(SC.SDL_SCANCODE_KP_0, Key.NumpadNum0);
+            MapKey(SC.SDL_SCANCODE_KP_1, Key.NumpadNum1);
+            MapKey(SC.SDL_SCANCODE_KP_2, Key.NumpadNum2);
+            MapKey(SC.SDL_SCANCODE_KP_3, Key.NumpadNum3);
+            MapKey(SC.SDL_SCANCODE_KP_4, Key.NumpadNum4);
+            MapKey(SC.SDL_SCANCODE_KP_5, Key.NumpadNum5);
+            MapKey(SC.SDL_SCANCODE_KP_6, Key.NumpadNum6);
+            MapKey(SC.SDL_SCANCODE_KP_7, Key.NumpadNum7);
+            MapKey(SC.SDL_SCANCODE_KP_8, Key.NumpadNum8);
+            MapKey(SC.SDL_SCANCODE_KP_9, Key.NumpadNum9);
+            MapKey(SC.SDL_SCANCODE_ESCAPE, Key.Escape);
+            MapKey(SC.SDL_SCANCODE_LCTRL, Key.Control);
+            MapKey(SC.SDL_SCANCODE_RCTRL, Key.Control);
+            MapKey(SC.SDL_SCANCODE_RSHIFT, Key.Shift);
+            MapKey(SC.SDL_SCANCODE_LSHIFT, Key.Shift);
+            MapKey(SC.SDL_SCANCODE_LALT, Key.Alt);
+            MapKey(SC.SDL_SCANCODE_RALT, Key.Alt);
+            MapKey(SC.SDL_SCANCODE_LGUI, Key.LSystem);
+            MapKey(SC.SDL_SCANCODE_RGUI, Key.RSystem);
+            MapKey(SC.SDL_SCANCODE_MENU, Key.Menu);
+            MapKey(SC.SDL_SCANCODE_LEFTBRACKET, Key.LBracket);
+            MapKey(SC.SDL_SCANCODE_RIGHTBRACKET, Key.RBracket);
+            MapKey(SC.SDL_SCANCODE_SEMICOLON, Key.SemiColon);
+            MapKey(SC.SDL_SCANCODE_COMMA, Key.Comma);
+            MapKey(SC.SDL_SCANCODE_PERIOD, Key.Period);
+            MapKey(SC.SDL_SCANCODE_APOSTROPHE, Key.Apostrophe);
+            MapKey(SC.SDL_SCANCODE_SLASH, Key.Slash);
+            MapKey(SC.SDL_SCANCODE_BACKSLASH, Key.BackSlash);
+            MapKey(SC.SDL_SCANCODE_GRAVE, Key.Tilde);
+            MapKey(SC.SDL_SCANCODE_EQUALS, Key.Equal);
+            MapKey(SC.SDL_SCANCODE_SPACE, Key.Space);
+            MapKey(SC.SDL_SCANCODE_RETURN, Key.Return);
+            MapKey(SC.SDL_SCANCODE_KP_ENTER, Key.NumpadEnter);
+            MapKey(SC.SDL_SCANCODE_BACKSPACE, Key.BackSpace);
+            MapKey(SC.SDL_SCANCODE_TAB, Key.Tab);
+            MapKey(SC.SDL_SCANCODE_PAGEUP, Key.PageUp);
+            MapKey(SC.SDL_SCANCODE_PAGEDOWN, Key.PageDown);
+            MapKey(SC.SDL_SCANCODE_END, Key.End);
+            MapKey(SC.SDL_SCANCODE_HOME, Key.Home);
+            MapKey(SC.SDL_SCANCODE_INSERT, Key.Insert);
+            MapKey(SC.SDL_SCANCODE_DELETE, Key.Delete);
+            MapKey(SC.SDL_SCANCODE_MINUS, Key.Minus);
+            MapKey(SC.SDL_SCANCODE_KP_PLUS, Key.NumpadAdd);
+            MapKey(SC.SDL_SCANCODE_KP_MINUS, Key.NumpadSubtract);
+            MapKey(SC.SDL_SCANCODE_KP_DIVIDE, Key.NumpadDivide);
+            MapKey(SC.SDL_SCANCODE_KP_MULTIPLY, Key.NumpadMultiply);
+            MapKey(SC.SDL_SCANCODE_KP_DECIMAL, Key.NumpadDecimal);
+            MapKey(SC.SDL_SCANCODE_LEFT, Key.Left);
+            MapKey(SC.SDL_SCANCODE_RIGHT, Key.Right);
+            MapKey(SC.SDL_SCANCODE_UP, Key.Up);
+            MapKey(SC.SDL_SCANCODE_DOWN, Key.Down);
+            MapKey(SC.SDL_SCANCODE_F1, Key.F1);
+            MapKey(SC.SDL_SCANCODE_F2, Key.F2);
+            MapKey(SC.SDL_SCANCODE_F3, Key.F3);
+            MapKey(SC.SDL_SCANCODE_F4, Key.F4);
+            MapKey(SC.SDL_SCANCODE_F5, Key.F5);
+            MapKey(SC.SDL_SCANCODE_F6, Key.F6);
+            MapKey(SC.SDL_SCANCODE_F7, Key.F7);
+            MapKey(SC.SDL_SCANCODE_F8, Key.F8);
+            MapKey(SC.SDL_SCANCODE_F9, Key.F9);
+            MapKey(SC.SDL_SCANCODE_F10, Key.F10);
+            MapKey(SC.SDL_SCANCODE_F11, Key.F11);
+            MapKey(SC.SDL_SCANCODE_F12, Key.F12);
+            MapKey(SC.SDL_SCANCODE_F13, Key.F13);
+            MapKey(SC.SDL_SCANCODE_F14, Key.F14);
+            MapKey(SC.SDL_SCANCODE_F15, Key.F15);
+            MapKey(SC.SDL_SCANCODE_F16, Key.F16);
+            MapKey(SC.SDL_SCANCODE_F17, Key.F17);
+            MapKey(SC.SDL_SCANCODE_F18, Key.F18);
+            MapKey(SC.SDL_SCANCODE_F19, Key.F19);
+            MapKey(SC.SDL_SCANCODE_F20, Key.F20);
+            MapKey(SC.SDL_SCANCODE_F21, Key.F21);
+            MapKey(SC.SDL_SCANCODE_F22, Key.F22);
+            MapKey(SC.SDL_SCANCODE_F23, Key.F23);
+            MapKey(SC.SDL_SCANCODE_F24, Key.F24);
+            MapKey(SC.SDL_SCANCODE_PAUSE, Key.Pause);
+
+            var keyMapReverse = new Dictionary<Key, SC>();
+
+            for (var code = 0; code < KeyMap.Length; code++)
+            {
+                var key = KeyMap[code];
+                if (key != Key.Unknown)
+                    keyMapReverse[key] = (SC) code;
+            }
+
+            KeyMapReverse = keyMapReverse.ToFrozenDictionary();
+
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            static void MapKey(SC code, Key key)
+            {
+                KeyMap[(int)code] = key;
+            }
+        }
+    }
+}

Robust.Client/Graphics/Clyde/Windowing/Sdl3.Monitor.cs

@@ -0,0 +1,133 @@
+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+using SDL3;
+
+namespace Robust.Client.Graphics.Clyde;
+
+internal partial class Clyde
+{
+    private sealed partial class Sdl3WindowingImpl
+    {
+        // NOTE: SDL3 calls them "displays". GLFW calls them monitors. GLFW's is the one I'm going with.
+
+        private int _nextMonitorId = 1;
+
+        private readonly Dictionary<int, WinThreadMonitorReg> _winThreadMonitors = new();
+        private readonly Dictionary<int, Sdl3MonitorReg> _monitors = new();
+
+        private unsafe void InitMonitors()
+        {
+            var displayList = (uint*)SDL.SDL_GetDisplays(out var count);
+            for (var i = 0; i < count; i++)
+            {
+                WinThreadSetupMonitor(displayList[i]);
+            }
+
+            SDL.SDL_free((nint)displayList);
+
+            // Needed so that monitor creation events get processed.
+            ProcessEvents();
+        }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private unsafe void WinThreadSetupMonitor(uint displayId)
+        {
+            var id = _nextMonitorId++;
+
+            var name = SDL.SDL_GetDisplayName(displayId);
+            var modePtr = (SDL.SDL_DisplayMode**)SDL.SDL_GetFullscreenDisplayModes(displayId, out var modeCount);
+            var curMode = (SDL.SDL_DisplayMode*)SDL.SDL_GetCurrentDisplayMode(displayId);
+            var modes = new VideoMode[modeCount];
+            for (var i = 0; i < modes.Length; i++)
+            {
+                modes[i] = ConvertVideoMode(in *modePtr[i]);
+            }
+
+            SDL.SDL_free((nint)modePtr);
+
+            _winThreadMonitors.Add(id, new WinThreadMonitorReg { DisplayId = displayId });
+
+            if (SDL.SDL_GetPrimaryDisplay() == displayId)
+                _clyde._primaryMonitorId = id;
+
+            SendEvent(new EventMonitorSetup
+            {
+                Id = id,
+                DisplayId = displayId,
+                Name = name,
+                AllModes = modes,
+                CurrentMode = ConvertVideoMode(in *curMode),
+            });
+        }
+
+        private static VideoMode ConvertVideoMode(in SDL.SDL_DisplayMode mode)
+        {
+            return new()
+            {
+                Width = (ushort)mode.w,
+                Height = (ushort)mode.h,
+                RefreshRate = (ushort)mode.refresh_rate,
+                // TODO: set bits count based on format (I'm lazy)
+                RedBits = 8,
+                GreenBits = 8,
+                BlueBits = 8,
+            };
+        }
+
+        private void ProcessSetupMonitor(EventMonitorSetup ev)
+        {
+            var impl = new MonitorHandle(
+                ev.Id,
+                ev.Name,
+                (ev.CurrentMode.Width, ev.CurrentMode.Height),
+                ev.CurrentMode.RefreshRate,
+                ev.AllModes);
+
+            _clyde._monitorHandles.Add(ev.Id, impl);
+            _monitors[ev.Id] = new Sdl3MonitorReg
+            {
+                DisplayId = ev.DisplayId,
+                Handle = impl
+            };
+        }
+
+        private void WinThreadDestroyMonitor(uint displayId)
+        {
+            var monitorId = GetMonitorIdFromDisplayId(displayId);
+            if (monitorId == 0)
+                return;
+
+            _winThreadMonitors.Remove(monitorId);
+            SendEvent(new EventMonitorDestroy { Id = monitorId });
+        }
+
+        private void ProcessEventDestroyMonitor(EventMonitorDestroy ev)
+        {
+            _monitors.Remove(ev.Id);
+            _clyde._monitorHandles.Remove(ev.Id);
+        }
+
+        private int GetMonitorIdFromDisplayId(uint displayId)
+        {
+            foreach (var (id, monitorReg) in _winThreadMonitors)
+            {
+                if (monitorReg.DisplayId == displayId)
+                {
+                    return id;
+                }
+            }
+
+            return 0;
+        }
+
+        private sealed class Sdl3MonitorReg : MonitorReg
+        {
+            public uint DisplayId;
+        }
+
+        private sealed class WinThreadMonitorReg
+        {
+            public uint DisplayId;
+        }
+    }
+}

Robust.Client/Graphics/Clyde/Windowing/Sdl3.RawEvent.cs

@@ -0,0 +1,282 @@
+using System;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using System.Threading.Tasks;
+using SDL3;
+using ET = SDL3.SDL.SDL_EventType;
+
+namespace Robust.Client.Graphics.Clyde;
+
+internal partial class Clyde
+{
+    private sealed partial class Sdl3WindowingImpl
+    {
+        [UnmanagedCallersOnly(CallConvs = [typeof(CallConvCdecl)])]
+        private static unsafe byte EventWatch(void* userdata, SDL.SDL_Event* sdlevent)
+        {
+            var obj = (Sdl3WindowingImpl)GCHandle.FromIntPtr((IntPtr)userdata).Target!;
+
+            obj.ProcessSdl3Event(in *sdlevent);
+
+            return 0;
+        }
+
+        private void ProcessSdl3Event(in SDL.SDL_Event ev)
+        {
+            switch ((ET)ev.type)
+            {
+                case ET.SDL_EVENT_WINDOW_PIXEL_SIZE_CHANGED:
+                    ProcessSdl3EventWindowPixelSizeChanged(in ev.window);
+                    break;
+                case ET.SDL_EVENT_WINDOW_DISPLAY_SCALE_CHANGED:
+                    ProcessSdl3EventWindowDisplayScaleChanged(in ev.window);
+                    break;
+                case ET.SDL_EVENT_WINDOW_CLOSE_REQUESTED:
+                case ET.SDL_EVENT_WINDOW_MOUSE_ENTER:
+                case ET.SDL_EVENT_WINDOW_MOUSE_LEAVE:
+                case ET.SDL_EVENT_WINDOW_MINIMIZED:
+                case ET.SDL_EVENT_WINDOW_RESTORED:
+                case ET.SDL_EVENT_WINDOW_FOCUS_GAINED:
+                case ET.SDL_EVENT_WINDOW_FOCUS_LOST:
+                case ET.SDL_EVENT_WINDOW_MOVED:
+                    ProcessSdl3EventWindowMisc(in ev.window);
+                    break;
+                case ET.SDL_EVENT_KEY_DOWN:
+                case ET.SDL_EVENT_KEY_UP:
+                    ProcessSdl3KeyEvent(in ev.key);
+                    break;
+                case ET.SDL_EVENT_TEXT_INPUT:
+                    ProcessSdl3EventTextInput(in ev.text);
+                    break;
+                case ET.SDL_EVENT_TEXT_EDITING:
+                    ProcessSdl3EventTextEditing(in ev.edit);
+                    break;
+                case ET.SDL_EVENT_KEYMAP_CHANGED:
+                    ProcessSdl3EventKeyMapChanged();
+                    break;
+                case ET.SDL_EVENT_MOUSE_MOTION:
+                    ProcessSdl3EventMouseMotion(in ev.motion);
+                    break;
+                case ET.SDL_EVENT_MOUSE_BUTTON_DOWN:
+                case ET.SDL_EVENT_MOUSE_BUTTON_UP:
+                    ProcessSdl3EventMouseButton(in ev.button);
+                    break;
+                case ET.SDL_EVENT_MOUSE_WHEEL:
+                    ProcessSdl3EventMouseWheel(in ev.wheel);
+                    break;
+                case ET.SDL_EVENT_DISPLAY_ADDED:
+                    WinThreadSetupMonitor(ev.display.displayID);
+                    break;
+                case ET.SDL_EVENT_DISPLAY_REMOVED:
+                    WinThreadDestroyMonitor(ev.display.displayID);
+                    break;
+                case ET.SDL_EVENT_QUIT:
+                    ProcessSdl3EventQuit();
+                    break;
+            }
+        }
+
+        private void ProcessSdl3EventQuit()
+        {
+            SendEvent(new EventQuit());
+        }
+
+        private void ProcessSdl3EventMouseWheel(in SDL.SDL_MouseWheelEvent ev)
+        {
+            SendEvent(new EventWheel { WindowId = ev.windowID, XOffset = ev.x, YOffset = ev.y });
+        }
+
+        private void ProcessSdl3EventMouseButton(in SDL.SDL_MouseButtonEvent ev)
+        {
+            var mods = SDL.SDL_GetModState();
+            SendEvent(new EventMouseButton
+            {
+                WindowId = ev.windowID,
+                Type = ev.type,
+                Button = ev.button,
+                Mods = mods
+            });
+        }
+
+        private void ProcessSdl3EventMouseMotion(in SDL.SDL_MouseMotionEvent ev)
+        {
+            SendEvent(new EventMouseMotion
+            {
+                WindowId = ev.windowID,
+                X = ev.x,
+                Y = ev.y,
+                XRel = ev.xrel,
+                YRel = ev.yrel
+            });
+        }
+
+        private unsafe void ProcessSdl3EventTextInput(in SDL.SDL_TextInputEvent ev)
+        {
+            var str = Marshal.PtrToStringUTF8((IntPtr)ev.text) ?? "";
+            SendEvent(new EventText { WindowId = ev.windowID, Text = str });
+        }
+
+        private unsafe void ProcessSdl3EventTextEditing(in SDL.SDL_TextEditingEvent ev)
+        {
+            var str = Marshal.PtrToStringUTF8((IntPtr)ev.text) ?? "";
+            SendEvent(new EventTextEditing
+            {
+                WindowId = ev.windowID,
+                Text = str,
+                Start = ev.start,
+                Length = ev.length
+            });
+        }
+
+        private void ProcessSdl3EventKeyMapChanged()
+        {
+            ReloadKeyMap();
+            SendEvent(new EventKeyMapChanged());
+        }
+
+        private void ProcessSdl3KeyEvent(in SDL.SDL_KeyboardEvent ev)
+        {
+            SendEvent(new EventKey
+            {
+                WindowId = ev.windowID,
+                Scancode = ev.scancode,
+                Type = ev.type,
+                Repeat = ev.repeat,
+                Mods = ev.mod,
+            });
+        }
+
+        private void ProcessSdl3EventWindowPixelSizeChanged(in SDL.SDL_WindowEvent ev)
+        {
+            var window = SDL.SDL_GetWindowFromID(ev.windowID);
+            SDL.SDL_GetWindowSize(window, out var width, out var height);
+            var fbW = ev.data1;
+            var fbH = ev.data2;
+
+            SendEvent(new EventWindowPixelSize
+            {
+                WindowId = ev.windowID,
+                Width = width,
+                Height = height,
+                FramebufferWidth = fbW,
+                FramebufferHeight = fbH,
+            });
+        }
+
+        private void ProcessSdl3EventWindowDisplayScaleChanged(in SDL.SDL_WindowEvent ev)
+        {
+            var window = SDL.SDL_GetWindowFromID(ev.windowID);
+            var scale = SDL.SDL_GetWindowDisplayScale(window);
+
+            SendEvent(new EventWindowContentScale { WindowId = ev.windowID, Scale = scale });
+        }
+
+        private void ProcessSdl3EventWindowMisc(in SDL.SDL_WindowEvent ev)
+        {
+            SendEvent(new EventWindowMisc
+            {
+                WindowId = ev.windowID,
+                EventId = ev.type,
+                Data1 = ev.data1,
+                Data2 = ev.data2
+            });
+        }
+
+        private abstract class EventBase;
+
+        private sealed class EventWindowCreate : EventBase
+        {
+            public required Sdl3WindowCreateResult Result;
+            public required TaskCompletionSource<Sdl3WindowCreateResult> Tcs;
+        }
+
+        private sealed class EventKey : EventBase
+        {
+            public uint WindowId;
+            public SDL.SDL_Scancode Scancode;
+            public ET Type;
+            public bool Repeat;
+            public SDL.SDL_Keymod Mods;
+        }
+
+        private sealed class EventMouseMotion : EventBase
+        {
+            public uint WindowId;
+            public float X;
+            public float Y;
+            public float XRel;
+            public float YRel;
+        }
+
+        private sealed class EventMouseButton : EventBase
+        {
+            public uint WindowId;
+            public ET Type;
+            public byte Button;
+            public SDL.SDL_Keymod Mods;
+        }
+
+        private sealed class EventText : EventBase
+        {
+            public uint WindowId;
+            public required string Text;
+        }
+
+        private sealed class EventTextEditing : EventBase
+        {
+            public uint WindowId;
+            public required string Text;
+            public int Start;
+            public int Length;
+        }
+
+        private sealed class EventWindowPixelSize : EventBase
+        {
+            public uint WindowId;
+            public int Width;
+            public int Height;
+            public int FramebufferWidth;
+            public int FramebufferHeight;
+        }
+
+        private sealed class EventWindowContentScale : EventBase
+        {
+            public uint WindowId;
+            public float Scale;
+        }
+
+        private sealed class EventWheel : EventBase
+        {
+            public uint WindowId;
+            public float XOffset;
+            public float YOffset;
+        }
+
+        // SDL_WindowEvents that don't need any handling on the window thread itself.
+        private sealed class EventWindowMisc : EventBase
+        {
+            public uint WindowId;
+            public ET EventId;
+            public int Data1;
+            public int Data2;
+        }
+
+        private sealed class EventMonitorSetup : EventBase
+        {
+            public int Id;
+            public uint DisplayId;
+            public required string Name;
+            public VideoMode CurrentMode;
+            public required VideoMode[] AllModes;
+        }
+
+        private sealed class EventMonitorDestroy : EventBase
+        {
+            public int Id;
+        }
+
+        private sealed class EventKeyMapChanged : EventBase;
+
+        private sealed class EventQuit : EventBase;
+    }
+}

Robust.Client/Graphics/Clyde/Windowing/Sdl3.Window.cs

@@ -0,0 +1,654 @@
+using System;
+using System.Numerics;
+using System.Runtime.CompilerServices;
+using System.Threading.Tasks;
+using Robust.Shared.Map;
+using Robust.Shared.Maths;
+using SDL3;
+using TerraFX.Interop.Windows;
+using TerraFX.Interop.Xlib;
+using BOOL = TerraFX.Interop.Windows.BOOL;
+using Windows = TerraFX.Interop.Windows.Windows;
+using GLAttr = SDL3.SDL.SDL_GLAttr;
+using X11Window = TerraFX.Interop.Xlib.Window;
+
+namespace Robust.Client.Graphics.Clyde;
+
+internal partial class Clyde
+{
+    private sealed partial class Sdl3WindowingImpl
+    {
+        private int _nextWindowId = 1;
+
+        public (WindowReg?, string? error) WindowCreate(
+            GLContextSpec? spec,
+            WindowCreateParameters parameters,
+            WindowReg? share,
+            WindowReg? owner)
+        {
+            nint shareWindow = 0;
+            nint shareContext = 0;
+            if (share is Sdl3WindowReg shareReg)
+            {
+                shareWindow = shareReg.Sdl3Window;
+                shareContext = shareReg.GlContext;
+            }
+
+            nint ownerPtr = 0;
+            if (owner is Sdl3WindowReg ownerReg)
+                ownerPtr = ownerReg.Sdl3Window;
+
+            var task = SharedWindowCreate(spec, parameters, shareWindow, shareContext, ownerPtr);
+
+            // Block the main thread (to avoid stuff like texture uploads being problematic).
+            WaitWindowCreate(task);
+
+#pragma warning disable RA0004
+            // Block above ensured task is done, this is safe.
+            var result = task.Result;
+#pragma warning restore RA0004
+            if (result.Reg != null)
+            {
+                result.Reg.Owner = result.Reg.Handle;
+            }
+
+            return (result.Reg, result.Error);
+        }
+
+        private void WaitWindowCreate(Task<Sdl3WindowCreateResult> windowTask)
+        {
+            while (!windowTask.IsCompleted)
+            {
+                // Keep processing events until the window task gives either an error or success.
+                WaitEvents();
+                ProcessEvents(single: true);
+            }
+        }
+
+        private Task<Sdl3WindowCreateResult> SharedWindowCreate(
+            GLContextSpec? glSpec,
+            WindowCreateParameters parameters,
+            nint shareWindow,
+            nint shareContext,
+            nint 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<Sdl3WindowCreateResult>();
+            SendCmd(new CmdWinCreate
+            {
+                GLSpec = glSpec,
+                Parameters = parameters,
+                ShareWindow = shareWindow,
+                ShareContext = shareContext,
+                OwnerWindow = owner,
+                Tcs = tcs
+            });
+            return tcs.Task;
+        }
+
+        private static void FinishWindowCreate(EventWindowCreate ev)
+        {
+            ev.Tcs.TrySetResult(ev.Result);
+        }
+
+        private void WinThreadWinCreate(CmdWinCreate cmd)
+        {
+            var (window, context) = CreateSdl3WindowForRenderer(
+                cmd.GLSpec,
+                cmd.Parameters,
+                cmd.ShareWindow,
+                cmd.ShareContext,
+                cmd.OwnerWindow);
+
+            if (window == 0)
+            {
+                var err = SDL.SDL_GetError();
+
+                SendEvent(new EventWindowCreate
+                {
+                    Result = new Sdl3WindowCreateResult { Error = err },
+                    Tcs = cmd.Tcs
+                });
+                return;
+            }
+
+            // We can't invoke the TCS directly from the windowing thread because:
+            // * it'd hit the synchronization context,
+            //   which would make (blocking) main window init more annoying.
+            // * it'd not be synchronized to other incoming window events correctly which might be icky.
+            // So we send the TCS back to the game thread
+            // which processes events in the correct order and has better control of stuff during init.
+            var reg = WinThreadSetupWindow(window, context);
+
+            SendEvent(new EventWindowCreate
+            {
+                Result = new Sdl3WindowCreateResult { Reg = reg },
+                Tcs = cmd.Tcs
+            });
+        }
+
+        private static void WinThreadWinDestroy(CmdWinDestroy cmd)
+        {
+            SDL.SDL_DestroyWindow(cmd.Window);
+        }
+
+        private (nint window, nint context) CreateSdl3WindowForRenderer(
+            GLContextSpec? spec,
+            WindowCreateParameters parameters,
+            nint shareWindow,
+            nint shareContext,
+            nint ownerWindow)
+        {
+            var createProps = SDL.SDL_CreateProperties();
+            SDL.SDL_SetBooleanProperty(createProps, SDL.SDL_PROP_WINDOW_CREATE_HIDDEN_BOOLEAN, true);
+            SDL.SDL_SetBooleanProperty(createProps, SDL.SDL_PROP_WINDOW_CREATE_RESIZABLE_BOOLEAN, true);
+            SDL.SDL_SetBooleanProperty(createProps, SDL.SDL_PROP_WINDOW_CREATE_HIGH_PIXEL_DENSITY_BOOLEAN, true);
+
+            if (spec is { } s)
+            {
+                SDL.SDL_SetBooleanProperty(createProps, SDL.SDL_PROP_WINDOW_CREATE_OPENGL_BOOLEAN, true);
+
+                SDL.SDL_GL_SetAttribute(GLAttr.SDL_GL_RED_SIZE, 8);
+                SDL.SDL_GL_SetAttribute(GLAttr.SDL_GL_GREEN_SIZE, 8);
+                SDL.SDL_GL_SetAttribute(GLAttr.SDL_GL_BLUE_SIZE, 8);
+                SDL.SDL_GL_SetAttribute(GLAttr.SDL_GL_ALPHA_SIZE, 8);
+                SDL.SDL_GL_SetAttribute(GLAttr.SDL_GL_STENCIL_SIZE, 8);
+                SDL.SDL_GL_SetAttribute(
+                    GLAttr.SDL_GL_FRAMEBUFFER_SRGB_CAPABLE,
+                    s.Profile == GLContextProfile.Es ? 0 : 1);
+                int ctxFlags = 0;
+#if DEBUG
+                ctxFlags |= SDL.SDL_GL_CONTEXT_DEBUG_FLAG;
+#endif
+                if (s.Profile == GLContextProfile.Core)
+                    ctxFlags |= SDL.SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG;
+
+                SDL.SDL_GL_SetAttribute(GLAttr.SDL_GL_CONTEXT_FLAGS, (int)ctxFlags);
+
+                if (shareContext != 0)
+                {
+                    SDL.SDL_GL_MakeCurrent(shareWindow, shareContext);
+                    SDL.SDL_GL_SetAttribute(GLAttr.SDL_GL_SHARE_WITH_CURRENT_CONTEXT, 1);
+                }
+                else
+                {
+                    SDL.SDL_GL_SetAttribute(GLAttr.SDL_GL_SHARE_WITH_CURRENT_CONTEXT, 0);
+                }
+
+                var profile = s.Profile switch
+                {
+                    GLContextProfile.Compatibility => SDL.SDL_GL_CONTEXT_PROFILE_COMPATIBILITY,
+                    GLContextProfile.Core => SDL.SDL_GL_CONTEXT_PROFILE_CORE,
+                    GLContextProfile.Es => SDL.SDL_GL_CONTEXT_PROFILE_ES,
+                    _ => SDL.SDL_GL_CONTEXT_PROFILE_COMPATIBILITY,
+                };
+
+                SDL.SDL_GL_SetAttribute(GLAttr.SDL_GL_CONTEXT_PROFILE_MASK, profile);
+                SDL.SDL_SetHint(SDL.SDL_HINT_OPENGL_ES_DRIVER, s.CreationApi == GLContextCreationApi.Egl ? "1" : "0");
+
+                SDL.SDL_GL_SetAttribute(GLAttr.SDL_GL_CONTEXT_MAJOR_VERSION, s.Major);
+                SDL.SDL_GL_SetAttribute(GLAttr.SDL_GL_CONTEXT_MINOR_VERSION, s.Minor);
+
+                if (s.CreationApi == GLContextCreationApi.Egl)
+                    WsiShared.EnsureEglAvailable();
+            }
+
+            if (parameters.Fullscreen)
+                SDL.SDL_SetBooleanProperty(createProps, SDL.SDL_PROP_WINDOW_CREATE_FULLSCREEN_BOOLEAN, true);
+
+            if ((parameters.Styles & OSWindowStyles.NoTitleBar) != 0)
+                SDL.SDL_SetBooleanProperty(createProps, SDL.SDL_PROP_WINDOW_CREATE_BORDERLESS_BOOLEAN, true);
+
+            if (ownerWindow != 0)
+            {
+                SDL.SDL_SetPointerProperty(createProps, SDL.SDL_PROP_WINDOW_CREATE_PARENT_POINTER, ownerWindow);
+
+                if (parameters.StartupLocation == WindowStartupLocation.CenterOwner)
+                {
+                    SDL.SDL_GetWindowSize(ownerWindow, out var parentW, out var parentH);
+                    SDL.SDL_GetWindowPosition(ownerWindow, out var parentX, out var parentY);
+
+                    SDL.SDL_SetNumberProperty(
+                        createProps,
+                        SDL.SDL_PROP_WINDOW_CREATE_X_NUMBER,
+                        parentX + (parentW - parameters.Width) / 2);
+                    SDL.SDL_SetNumberProperty(
+                        createProps,
+                        SDL.SDL_PROP_WINDOW_CREATE_Y_NUMBER,
+                        parentY + (parentH - parameters.Height) / 2);
+                }
+            }
+
+            SDL.SDL_SetNumberProperty(createProps, SDL.SDL_PROP_WINDOW_CREATE_WIDTH_NUMBER, parameters.Width);
+            SDL.SDL_SetNumberProperty(createProps, SDL.SDL_PROP_WINDOW_CREATE_HEIGHT_NUMBER, parameters.Height);
+            SDL.SDL_SetStringProperty(createProps, SDL.SDL_PROP_WINDOW_CREATE_TITLE_STRING, parameters.Title);
+
+            // ---> CREATE <---
+            var window = SDL.SDL_CreateWindowWithProperties(createProps);
+
+            SDL.SDL_DestroyProperties(createProps);
+
+            if (window == 0)
+                return default;
+
+            nint glContext = SDL.SDL_GL_CreateContext(window);
+            if (glContext == 0)
+            {
+                SDL.SDL_DestroyWindow(window);
+                return default;
+            }
+
+            if ((parameters.Styles & OSWindowStyles.NoTitleOptions) != 0)
+            {
+                var props = SDL.SDL_GetWindowProperties(window);
+                switch (_videoDriver)
+                {
+                    case SdlVideoDriver.Windows:
+                    {
+                        var hWnd = SDL.SDL_GetPointerProperty(
+                            props,
+                            SDL.SDL_PROP_WINDOW_WIN32_HWND_POINTER,
+                            0);
+                        WsiShared.SetWindowStyleNoTitleOptionsWindows((HWND)hWnd);
+                        break;
+                    }
+                    case SdlVideoDriver.X11:
+                        unsafe
+                        {
+                            var x11Display = (Display*)SDL.SDL_GetPointerProperty(
+                                props,
+                                SDL.SDL_PROP_WINDOW_X11_DISPLAY_POINTER,
+                                0);
+                            var x11Window = (X11Window)SDL.SDL_GetNumberProperty(
+                                props,
+                                SDL.SDL_PROP_WINDOW_X11_WINDOW_NUMBER,
+                                0);
+                            WsiShared.SetWindowStyleNoTitleOptionsX11(x11Display, x11Window);
+                            break;
+                        }
+
+                    default:
+                        _sawmill.Warning("OSWindowStyles.NoTitleOptions not implemented on this video driver");
+                        break;
+                }
+            }
+
+            // TODO: Monitors, window maximize.
+
+            // Make sure window thread doesn't keep hold of the GL context.
+            SDL.SDL_GL_MakeCurrent(IntPtr.Zero, IntPtr.Zero);
+
+            if (parameters.Visible)
+                SDL.SDL_ShowWindow(window);
+
+            return (window, glContext);
+        }
+
+        private Sdl3WindowReg WinThreadSetupWindow(nint window, nint context)
+        {
+            var reg = new Sdl3WindowReg
+            {
+                Sdl3Window = window,
+                GlContext = context,
+                WindowId = SDL.SDL_GetWindowID(window),
+                Id = new WindowId(_nextWindowId++)
+            };
+            var handle = new WindowHandle(_clyde, reg);
+            reg.Handle = handle;
+
+            var windowProps = SDL.SDL_GetWindowProperties(window);
+            switch (_videoDriver)
+            {
+                case SdlVideoDriver.Windows:
+                    reg.WindowsHwnd = SDL.SDL_GetPointerProperty(
+                        windowProps,
+                        SDL.SDL_PROP_WINDOW_WIN32_HWND_POINTER,
+                        0);
+                    break;
+                case SdlVideoDriver.X11:
+                    reg.X11Display = SDL.SDL_GetPointerProperty(
+                        windowProps,
+                        SDL.SDL_PROP_WINDOW_X11_DISPLAY_POINTER,
+                        0);
+                    reg.X11Id = (uint)SDL.SDL_GetNumberProperty(windowProps, SDL.SDL_PROP_WINDOW_X11_WINDOW_NUMBER, 0);
+                    break;
+            }
+
+            AssignWindowIconToWindow(window);
+
+            SDL.SDL_GetWindowSizeInPixels(window, out var fbW, out var fbH);
+            reg.FramebufferSize = (fbW, fbH);
+
+            var scale = SDL.SDL_GetWindowDisplayScale(window);
+            reg.WindowScale = new Vector2(scale, scale);
+
+            SDL.SDL_GetWindowSize(window, out var w, out var h);
+            reg.PrevWindowSize = reg.WindowSize = (w, h);
+
+            SDL.SDL_GetWindowPosition(window, out var x, out var y);
+            reg.PrevWindowPos = reg.WindowPos = (x, y);
+
+            reg.PixelRatio = reg.FramebufferSize / (Vector2)reg.WindowSize;
+
+            return reg;
+        }
+
+        public void WindowDestroy(WindowReg window)
+        {
+            var reg = (Sdl3WindowReg)window;
+            SendCmd(new CmdWinDestroy
+            {
+                Window = reg.Sdl3Window,
+                HadOwner = window.Owner != null
+            });
+        }
+
+        public void UpdateMainWindowMode()
+        {
+            if (_clyde._mainWindow == null)
+                return;
+
+            var win = (Sdl3WindowReg)_clyde._mainWindow;
+
+            if (_clyde._windowMode == WindowMode.Fullscreen)
+            {
+                win.PrevWindowSize = win.WindowSize;
+                win.PrevWindowPos = win.WindowPos;
+
+                SendCmd(new CmdWinWinSetFullscreen
+                {
+                    Window = win.Sdl3Window,
+                });
+            }
+            else
+            {
+                SendCmd(new CmdWinSetWindowed
+                {
+                    Window = win.Sdl3Window,
+                    Width = win.PrevWindowSize.X,
+                    Height = win.PrevWindowSize.Y,
+                    PosX = win.PrevWindowPos.X,
+                    PosY = win.PrevWindowPos.Y
+                });
+            }
+        }
+
+        private static void WinThreadWinSetFullscreen(CmdWinWinSetFullscreen cmd)
+        {
+            SDL.SDL_SetWindowFullscreen(cmd.Window, true);
+        }
+
+        private static void WinThreadWinSetWindowed(CmdWinSetWindowed cmd)
+        {
+            SDL.SDL_SetWindowFullscreen(cmd.Window, false);
+            SDL.SDL_SetWindowSize(cmd.Window, cmd.Width, cmd.Height);
+            SDL.SDL_SetWindowPosition(cmd.Window, cmd.PosX, cmd.PosY);
+        }
+
+        public void WindowSetTitle(WindowReg window, string title)
+        {
+            SendCmd(new CmdWinSetTitle
+            {
+                Window = WinPtr(window),
+                Title = title,
+            });
+        }
+
+        private static void WinThreadWinSetTitle(CmdWinSetTitle cmd)
+        {
+            SDL.SDL_SetWindowTitle(cmd.Window, cmd.Title);
+        }
+
+        public void WindowSetMonitor(WindowReg window, IClydeMonitor monitor)
+        {
+            // API isn't really used and kinda wack, don't feel like figuring it out for SDL3 yet.
+            _sawmill.Warning("WindowSetMonitor not implemented on SDL3");
+        }
+
+        public void WindowSetSize(WindowReg window, Vector2i size)
+        {
+            SendCmd(new CmdWinSetSize { Window = WinPtr(window), W = size.X, H = size.Y });
+        }
+
+        public void WindowSetVisible(WindowReg window, bool visible)
+        {
+            window.IsVisible = visible;
+            SendCmd(new CmdWinSetVisible { Window = WinPtr(window), Visible = visible });
+        }
+
+        private static void WinThreadWinSetSize(CmdWinSetSize cmd)
+        {
+            SDL.SDL_SetWindowSize(cmd.Window, cmd.W, cmd.H);
+        }
+
+        private static void WinThreadWinSetVisible(CmdWinSetVisible cmd)
+        {
+            if (cmd.Visible)
+                SDL.SDL_ShowWindow(cmd.Window);
+            else
+                SDL.SDL_HideWindow(cmd.Window);
+        }
+
+        public void WindowRequestAttention(WindowReg window)
+        {
+            SendCmd(new CmdWinRequestAttention { Window = WinPtr(window) });
+        }
+
+        private void WinThreadWinRequestAttention(CmdWinRequestAttention cmd)
+        {
+            var res = SDL.SDL_FlashWindow(cmd.Window, SDL.SDL_FlashOperation.SDL_FLASH_UNTIL_FOCUSED);
+            if (!res)
+                _sawmill.Error("Failed to flash window: {error}", SDL.SDL_GetError());
+        }
+
+        public unsafe void WindowSwapBuffers(WindowReg window)
+        {
+            var reg = (Sdl3WindowReg)window;
+            var windowPtr = WinPtr(reg);
+
+            // On Windows, SwapBuffers does not correctly sync to the DWM compositor.
+            // This means OpenGL vsync is effectively broken by default on Windows.
+            // We manually sync via DwmFlush(). GLFW does this automatically, SDL3 does not.
+            //
+            // Windows DwmFlush logic partly taken from:
+            // https://github.com/love2d/love/blob/5175b0d1b599ea4c7b929f6b4282dd379fa116b8/src/modules/window/sdl/Window.cpp#L1018
+            // https://github.com/glfw/glfw/blob/d3ede7b6847b66cf30b067214b2b4b126d4c729b/src/wgl_context.c#L321-L340
+            // See also: https://github.com/libsdl-org/SDL/issues/5797
+
+            var dwmFlush = false;
+            var swapInterval = 0;
+
+            if (OperatingSystem.IsWindows() && !reg.Fullscreen && reg.SwapInterval > 0)
+            {
+                BOOL compositing;
+                // 6.2 is Windows 8
+                // https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/wdm/ns-wdm-_osversioninfoexw
+                if (OperatingSystem.IsWindowsVersionAtLeast(6, 2)
+                    || Windows.SUCCEEDED(Windows.DwmIsCompositionEnabled(&compositing)) && compositing)
+                {
+                    var curCtx = SDL.SDL_GL_GetCurrentContext();
+                    var curWin = SDL.SDL_GL_GetCurrentWindow();
+
+                    if (curCtx != reg.GlContext || curWin != reg.Sdl3Window)
+                        throw new InvalidOperationException("Window context must be current!");
+
+                    SDL.SDL_GL_SetSwapInterval(0);
+                    dwmFlush = true;
+                    swapInterval = reg.SwapInterval;
+                }
+            }
+
+            SDL.SDL_GL_SwapWindow(windowPtr);
+
+            if (dwmFlush)
+            {
+                var i = swapInterval;
+                while (i-- > 0)
+                {
+                    Windows.DwmFlush();
+                }
+
+                SDL.SDL_GL_SetSwapInterval(swapInterval);
+            }
+        }
+
+        public uint? WindowGetX11Id(WindowReg window)
+        {
+            CheckWindowDisposed(window);
+
+            if (_videoDriver != SdlVideoDriver.X11)
+                return null;
+
+            var reg = (Sdl3WindowReg)window;
+            return reg.X11Id;
+        }
+
+        public nint? WindowGetX11Display(WindowReg window)
+        {
+            CheckWindowDisposed(window);
+
+            if (_videoDriver != SdlVideoDriver.X11)
+                return null;
+
+            var reg = (Sdl3WindowReg)window;
+            return reg.X11Display;
+        }
+
+        public nint? WindowGetWin32Window(WindowReg window)
+        {
+            CheckWindowDisposed(window);
+
+            if (_videoDriver != SdlVideoDriver.Windows)
+                return null;
+
+            var reg = (Sdl3WindowReg)window;
+            return reg.WindowsHwnd;
+        }
+
+        public void RunOnWindowThread(Action a)
+        {
+            SendCmd(new CmdRunAction { Action = a });
+        }
+
+        public void TextInputSetRect(WindowReg reg, UIBox2i rect, int cursor)
+        {
+            SendCmd(new CmdTextInputSetRect
+            {
+                Window = WinPtr(reg),
+                Rect = new SDL.SDL_Rect
+                {
+                    x = rect.Left,
+                    y = rect.Top,
+                    w = rect.Width,
+                    h = rect.Height
+                },
+                Cursor = cursor
+            });
+        }
+
+        private static void WinThreadSetTextInputRect(CmdTextInputSetRect cmdTextInput)
+        {
+            var rect = cmdTextInput.Rect;
+            SDL.SDL_SetTextInputArea(cmdTextInput.Window, ref rect, cmdTextInput.Cursor);
+        }
+
+        public void TextInputStart(WindowReg reg)
+        {
+            SendCmd(new CmdTextInputStart { Window = WinPtr(reg) });
+        }
+
+        private static void WinThreadStartTextInput(CmdTextInputStart cmd)
+        {
+            SDL.SDL_StartTextInput(cmd.Window);
+        }
+
+        public void TextInputStop(WindowReg reg)
+        {
+            SendCmd(new CmdTextInputStop { Window = WinPtr(reg) });
+        }
+
+        private static void WinThreadStopTextInput(CmdTextInputStop cmd)
+        {
+            SDL.SDL_StopTextInput(cmd.Window);
+        }
+
+        public void ClipboardSetText(WindowReg mainWindow, string text)
+        {
+            SendCmd(new CmdSetClipboard { Text = text });
+        }
+
+        private void WinThreadSetClipboard(CmdSetClipboard cmd)
+        {
+            var res = SDL.SDL_SetClipboardText(cmd.Text);
+            if (res)
+                _sawmill.Error("Failed to set clipboard text: {error}", SDL.SDL_GetError());
+        }
+
+        public Task<string> ClipboardGetText(WindowReg mainWindow)
+        {
+            var tcs = new TaskCompletionSource<string>();
+            SendCmd(new CmdGetClipboard { Tcs = tcs });
+            return tcs.Task;
+        }
+
+        private static void WinThreadGetClipboard(CmdGetClipboard cmd)
+        {
+            cmd.Tcs.TrySetResult(SDL.SDL_GetClipboardText());
+        }
+
+        private static void CheckWindowDisposed(WindowReg reg)
+        {
+            if (reg.IsDisposed)
+                throw new ObjectDisposedException("Window disposed");
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private static nint WinPtr(WindowReg reg) => ((Sdl3WindowReg)reg).Sdl3Window;
+
+        private WindowReg? FindWindow(uint windowId)
+        {
+            foreach (var windowReg in _clyde._windows)
+            {
+                var glfwReg = (Sdl3WindowReg)windowReg;
+                if (glfwReg.WindowId == windowId)
+                    return windowReg;
+            }
+
+            return null;
+        }
+
+
+        private sealed class Sdl3WindowReg : WindowReg
+        {
+            public nint Sdl3Window;
+            public uint WindowId;
+            public nint GlContext;
+#pragma warning disable CS0649
+            public bool Fullscreen;
+#pragma warning restore CS0649
+            public int SwapInterval;
+
+            // Kept around to avoid it being GCd.
+            public CursorImpl? Cursor;
+
+            public nint WindowsHwnd;
+            public nint X11Display;
+            public uint X11Id;
+        }
+    }
+}

Robust.Client/Graphics/Clyde/Windowing/Sdl3.WindowIcons.cs

@@ -0,0 +1,105 @@
+using System;
+using System.Linq;
+using System.Runtime.InteropServices;
+using Robust.Client.Utility;
+using SDL3;
+using SixLabors.ImageSharp;
+using SixLabors.ImageSharp.PixelFormats;
+using TerraFX.Interop.Windows;
+
+namespace Robust.Client.Graphics.Clyde;
+
+internal partial class Clyde
+{
+    private sealed unsafe partial class Sdl3WindowingImpl
+    {
+        // Experimentally on my system, SM_CXICON is 32.
+        // I doubt MS is ever changing that, so...
+        // I wish SDL would take care of this instead of us having to figure out what the "main" icon is. Ugh.
+        private const int MainWindowIconSize = 32;
+
+        // Writing this out like this makes me realize we're spending multiple hundred KBs on storing the window icon.
+        // You know, come to think about it, what if we used LZ4 or Zstd to compress the window icon stored here?
+        // This is absolutely not worth the optimization but hilarious for me to think about.
+
+        // The surface used for the window icon.
+        // This may store additional surfaces as alternate forms.
+        private nint _windowIconSurface;
+        // The data for all the window icons surfaces.
+        // Must be kept around! Pinned!
+        // ReSharper disable once CollectionNeverQueried.Local
+        private byte[][]? _windowIconData;
+
+        private void LoadWindowIcons()
+        {
+            // Sort such that closest to 64 is first.
+            // SDL3 doesn't "figure it out itself" as much as GLFW does, which sucks.
+            var icons = _clyde.LoadWindowIcons().OrderBy(i => Math.Abs(i.Width - MainWindowIconSize)).ToArray();
+            if (icons.Length == 0)
+            {
+                // No window icons at all!
+                return;
+            }
+
+            _windowIconData = new byte[icons.Length][];
+
+            var mainImg = icons[0];
+
+            _sawmill.Verbose(
+                "Have {iconCount} window icons available, choosing {mainIconWidth}x{mainIconHeight} as main",
+                icons.Length,
+                mainImg.Width,
+                mainImg.Height);
+
+            (_windowIconSurface, var mainData) = CreateSurfaceFromImage(mainImg);
+            _windowIconData[0] = mainData;
+
+            for (var i = 1; i < icons.Length; i++)
+            {
+                var (surface, data) = CreateSurfaceFromImage(icons[i]);
+                _windowIconData[i] = data;
+                SDL.SDL_AddSurfaceAlternateImage(_windowIconSurface, surface);
+                // Kept alive by the main surface.
+                SDL.SDL_DestroySurface(surface);
+            }
+
+            return;
+
+            static (nint, byte[]) CreateSurfaceFromImage(Image<Rgba32> img)
+            {
+                var span = MemoryMarshal.AsBytes(img.GetPixelSpan());
+                var copied = GC.AllocateUninitializedArray<byte>(span.Length, pinned: true);
+
+                span.CopyTo(copied);
+
+                IntPtr surface;
+                fixed (byte* ptr = copied)
+                {
+                    surface = SDL.SDL_CreateSurfaceFrom(
+                        img.Width,
+                        img.Height,
+                        SDL.SDL_PixelFormat.SDL_PIXELFORMAT_ABGR8888,
+                        (IntPtr)ptr,
+                        sizeof(Rgba32) * img.Width);
+                }
+
+                return (surface, copied);
+            }
+        }
+
+        private void DestroyWindowIcons()
+        {
+            SDL.SDL_DestroySurface(_windowIconSurface);
+            _windowIconSurface = 0;
+            _windowIconData = null;
+        }
+
+        private void AssignWindowIconToWindow(nint window)
+        {
+            if (_windowIconSurface == 0)
+                return;
+
+            SDL.SDL_SetWindowIcon(window, (nint) _windowIconSurface);
+        }
+    }
+}

Robust.Client/Graphics/Clyde/Windowing/Sdl3.WindowThread.cs

@@ -4,15 +4,15 @@ using System.Threading.Channels;
 using System.Threading.Tasks;
 using Robust.Shared;
 using Robust.Shared.Maths;
+using SDL3;
 using SixLabors.ImageSharp;
 using SixLabors.ImageSharp.PixelFormats;
-using static SDL2.SDL;
 
 namespace Robust.Client.Graphics.Clyde;
 
 internal partial class Clyde
 {
-    private sealed partial class Sdl2WindowingImpl
+    private sealed partial class Sdl3WindowingImpl
     {
         private bool _windowingRunning;
         private ChannelWriter<CmdBase> _cmdWriter = default!;
@@ -29,34 +29,34 @@ internal partial class Clyde
 
             while (_windowingRunning)
             {
-                var res = SDL_WaitEvent(out Unsafe.NullRef<SDL_Event>());
-                if (res == 0)
+                var res = SDL.SDL_WaitEvent(out Unsafe.NullRef<SDL.SDL_Event>());
+                if (!res)
                 {
-                    _sawmill.Error("Error while waiting on SDL2 events: {error}", SDL_GetError());
+                    _sawmill.Error("Error while waiting on SDL3 events: {error}", SDL.SDL_GetError());
                     continue; // Assume it's a transient failure?
                 }
 
-                while (SDL_PollEvent(out _) == 1)
+                while (SDL.SDL_PollEvent(out _))
                 {
                     // We let callbacks process all events because of stuff like resizing.
                 }
 
                 while (_cmdReader.TryRead(out var cmd) && _windowingRunning)
                 {
-                    ProcessSdl2Cmd(cmd);
+                    ProcessSdl3Cmd(cmd);
                 }
             }
         }
 
         public void PollEvents()
         {
-            while (SDL_PollEvent(out _) == 1)
+            while (SDL.SDL_PollEvent(out _))
             {
                 // We let callbacks process all events because of stuff like resizing.
             }
         }
 
-        private void ProcessSdl2Cmd(CmdBase cmdb)
+        private void ProcessSdl3Cmd(CmdBase cmdb)
         {
             switch (cmdb)
             {
@@ -113,20 +113,24 @@ internal partial class Clyde
                     WinThreadWinCursorSet(cmd);
                     break;
 
-                case CmdWinWinSetMode cmd:
-                    WinThreadWinSetMode(cmd);
+                case CmdWinWinSetFullscreen cmd:
+                    WinThreadWinSetFullscreen(cmd);
+                    break;
+
+                case CmdWinSetWindowed cmd:
+                    WinThreadWinSetWindowed(cmd);
                     break;
 
                 case CmdTextInputSetRect cmd:
                     WinThreadSetTextInputRect(cmd);
                     break;
 
-                case CmdTextInputStart:
-                    WinThreadStartTextInput();
+                case CmdTextInputStart cmd:
+                    WinThreadStartTextInput(cmd);
                     break;
 
-                case CmdTextInputStop:
-                    WinThreadStopTextInput();
+                case CmdTextInputStop cmd:
+                    WinThreadStopTextInput(cmd);
                     break;
             }
         }
@@ -171,25 +175,25 @@ internal partial class Clyde
             _eventWriter = eventChannel.Writer;
         }
 
-        private unsafe void SendCmd(CmdBase cmd)
+        private void SendCmd(CmdBase cmd)
         {
             if (_clyde._threadWindowApi)
             {
                 _cmdWriter.TryWrite(cmd);
 
-                SDL_Event ev = default;
-                ev.type = (SDL_EventType)_sdlEventWakeup;
+                SDL.SDL_Event ev = default;
+                ev.type = _sdlEventWakeup;
                 // Post empty event to unstuck WaitEvents if necessary.
                 // This self-registered event type is ignored by the winthread, but it'll still wake it up.
 
                 // This can fail if the event queue is full.
                 // That's not really a problem since in that case something else will be sure to wake the thread up anyways.
                 // NOTE: have to avoid using PushEvents since that invokes callbacks which causes a deadlock.
-                SDL_PeepEvents(&ev, 1, SDL_eventaction.SDL_ADDEVENT, ev.type, ev.type);
+                SDL.SDL_PeepEvents(new Span<SDL.SDL_Event>(ref ev), 1, SDL.SDL_EventAction.SDL_ADDEVENT, ev.type, ev.type);
             }
             else
             {
-                ProcessSdl2Cmd(cmd);
+                ProcessSdl3Cmd(cmd);
             }
         }
 
@@ -211,93 +215,119 @@ internal partial class Clyde
         }
 
 
-        private abstract record CmdBase;
+        private abstract class CmdBase;
 
-        private sealed record CmdTerminate : CmdBase;
+        private sealed class CmdTerminate : CmdBase;
 
-        private sealed record CmdWinCreate(
-            GLContextSpec? GLSpec,
-            WindowCreateParameters Parameters,
-            nint ShareWindow,
-            nint ShareContext,
-            nint OwnerWindow,
-            TaskCompletionSource<Sdl2WindowCreateResult> Tcs
-        ) : CmdBase;
+        private sealed class CmdWinCreate : CmdBase
+        {
+            public required GLContextSpec? GLSpec;
+            public required WindowCreateParameters Parameters;
+            public required nint ShareWindow;
+            public required nint ShareContext;
+            public required nint OwnerWindow;
+            public required TaskCompletionSource<Sdl3WindowCreateResult> Tcs;
+        }
 
-        private sealed record CmdWinDestroy(
-            nint Window,
-            bool HadOwner
-        ) : CmdBase;
+        private sealed class CmdWinDestroy : CmdBase
+        {
+            public nint Window;
+            public bool HadOwner;
+        }
 
-        private sealed record Sdl2WindowCreateResult(
-            Sdl2WindowReg? Reg,
-            string? Error
-        );
+        private sealed class Sdl3WindowCreateResult
+        {
+            public Sdl3WindowReg? Reg;
+            public string? Error;
+        }
 
-        private sealed record CmdRunAction(
-            Action Action
-        ) : CmdBase;
+        private sealed class CmdRunAction : CmdBase
+        {
+            public required Action Action;
+        }
 
-        private sealed record CmdSetClipboard(
-            string Text
-        ) : CmdBase;
+        private sealed class CmdSetClipboard : CmdBase
+        {
+            public required string Text;
+        }
 
-        private sealed record CmdGetClipboard(
-            TaskCompletionSource<string> Tcs
-        ) : CmdBase;
+        private sealed class CmdGetClipboard : CmdBase
+        {
+            public required TaskCompletionSource<string> Tcs;
+        }
 
-        private sealed record CmdWinRequestAttention(
-            nint Window
-        ) : CmdBase;
+        private sealed class CmdWinRequestAttention : CmdBase
+        {
+            public nint Window;
+        }
 
-        private sealed record CmdWinSetSize(
-            nint Window,
-            int W, int H
-        ) : CmdBase;
+        private sealed class CmdWinSetSize : CmdBase
+        {
+            public nint Window;
+            public int W;
+            public int H;
+        }
 
-        private sealed record CmdWinSetVisible(
-            nint Window,
-            bool Visible
-        ) : CmdBase;
+        private sealed class CmdWinSetVisible : CmdBase
+        {
+            public nint Window;
+            public bool Visible;
+        }
 
-        private sealed record CmdWinSetTitle(
-            nint Window,
-            string Title
-        ) : CmdBase;
+        private sealed class CmdWinSetTitle : CmdBase
+        {
+            public nint Window;
+            public required string Title;
+        }
 
-        private sealed record CmdCursorCreate(
-            Image<Rgba32> Bytes,
-            Vector2i Hotspot,
-            ClydeHandle Cursor
-        ) : CmdBase;
+        private sealed class CmdCursorCreate : CmdBase
+        {
+            public required Image<Rgba32> Bytes;
+            public Vector2i Hotspot;
+            public ClydeHandle Cursor;
+        }
 
-        private sealed record CmdCursorDestroy(
-            ClydeHandle Cursor
-        ) : CmdBase;
+        private sealed class CmdCursorDestroy : CmdBase
+        {
+            public ClydeHandle Cursor;
+        }
 
-        private sealed record CmdWinCursorSet(
-            nint Window,
-            ClydeHandle Cursor
-        ) : CmdBase;
+        private sealed class CmdWinCursorSet : CmdBase
+        {
+            public nint Window;
+            public ClydeHandle Cursor;
+        }
 
-        private sealed record CmdWinWinSetMode(
-            nint Window,
-            WindowMode Mode
-        ) : CmdBase;
+        private sealed class CmdWinWinSetFullscreen : CmdBase
+        {
+            public nint Window;
+        }
+
+        private sealed class CmdWinSetWindowed : CmdBase
+        {
+            public nint Window;
+            public int Width;
+            public int Height;
+            public int PosX;
+            public int PosY;
+        }
 
         // IME
-        private sealed record CmdTextInputStart : CmdBase
+        private sealed class CmdTextInputStart : CmdBase
         {
-            public static readonly CmdTextInputStart Instance = new();
+            public nint Window;
         }
 
-        private sealed record CmdTextInputStop : CmdBase
+        private sealed class CmdTextInputStop : CmdBase
         {
-            public static readonly CmdTextInputStop Instance = new();
+            public nint Window;
         }
 
-        private sealed record CmdTextInputSetRect(
-            SDL_Rect Rect
-        ) : CmdBase;
+        private sealed class CmdTextInputSetRect : CmdBase
+        {
+            public nint Window;
+            public SDL.SDL_Rect Rect;
+            public int Cursor;
+        }
     }
 }

Robust.Client/Graphics/Clyde/Windowing/Sdl3.cs

@@ -0,0 +1,226 @@
+using System;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using System.Threading;
+using Robust.Shared.Configuration;
+using Robust.Shared.IoC;
+using Robust.Shared.Log;
+using SDL3;
+using DependencyAttribute = Robust.Shared.IoC.DependencyAttribute;
+
+namespace Robust.Client.Graphics.Clyde;
+
+internal partial class Clyde
+{
+    private sealed partial class Sdl3WindowingImpl : IWindowingImpl
+    {
+        [Dependency] private readonly ILogManager _logManager = default!;
+        [Dependency] private readonly IConfigurationManager _cfg = default!;
+
+        private readonly Clyde _clyde;
+        private GCHandle _selfGCHandle;
+
+        private readonly ISawmill _sawmill;
+        private readonly ISawmill _sawmillSdl3;
+
+        private SdlVideoDriver _videoDriver;
+
+        public Sdl3WindowingImpl(Clyde clyde, IDependencyCollection deps)
+        {
+            _clyde = clyde;
+            deps.InjectDependencies(this, true);
+
+            _sawmill = _logManager.GetSawmill("clyde.win");
+            _sawmillSdl3 = _logManager.GetSawmill("clyde.win.sdl3");
+        }
+
+        public bool Init()
+        {
+            InitChannels();
+
+            if (!InitSdl3())
+                return false;
+
+            return true;
+        }
+
+        private unsafe bool InitSdl3()
+        {
+            CheckThreadApartment();
+
+            _selfGCHandle = GCHandle.Alloc(this, GCHandleType.Normal);
+
+            SDL.SDL_SetLogPriorities(SDL.SDL_LogPriority.SDL_LOG_PRIORITY_VERBOSE);
+            SDL.SDL_SetLogOutputFunction(&LogOutputFunction, (void*) GCHandle.ToIntPtr(_selfGCHandle));
+
+            SDL.SDL_SetHint(SDL.SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, "1");
+            SDL.SDL_SetHint(SDL.SDL_HINT_IME_IMPLEMENTED_UI, "composition");
+
+            // SDL3's GameInput support is currently broken and leaving it on
+            // causes a "that operation is not supported" error to be logged on startup.
+            // https://github.com/libsdl-org/SDL/issues/11813
+            SDL.SDL_SetHint(SDL.SDL_HINT_WINDOWS_GAMEINPUT, "0");
+
+            var res = SDL.SDL_Init(SDL.SDL_InitFlags.SDL_INIT_VIDEO | SDL.SDL_InitFlags.SDL_INIT_EVENTS);
+            if (!res)
+            {
+                _sawmill.Fatal("Failed to initialize SDL3: {error}", SDL.SDL_GetError());
+                return false;
+            }
+
+            var version = SDL.SDL_GetVersion();
+            var videoDriver = SDL.SDL_GetCurrentVideoDriver();
+            _sawmill.Debug(
+                "SDL3 initialized, version: {major}.{minor}.{patch}, video driver: {videoDriver}",
+                SDL.SDL_VERSIONNUM_MAJOR(version),
+                SDL.SDL_VERSIONNUM_MINOR(version),
+                SDL.SDL_VERSIONNUM_MICRO(version),
+                videoDriver);
+
+            LoadSdl3VideoDriver();
+
+            _sdlEventWakeup = SDL.SDL_RegisterEvents(1);
+            if (_sdlEventWakeup == 0)
+                throw new InvalidOperationException("SDL_RegisterEvents failed");
+
+            LoadWindowIcons();
+            InitCursors();
+            InitMonitors();
+            ReloadKeyMap();
+
+            SDL.SDL_AddEventWatch(&EventWatch, (void*) GCHandle.ToIntPtr(_selfGCHandle));
+
+            return true;
+        }
+
+        private void CheckThreadApartment()
+        {
+            if (!OperatingSystem.IsWindows())
+                return;
+
+            if (Thread.CurrentThread.GetApartmentState() != ApartmentState.STA)
+                _sawmill.Error("Thread apartment state isn't STA. This will likely break things!!!");
+        }
+
+        private void LoadSdl3VideoDriver()
+        {
+            _videoDriver = SDL.SDL_GetCurrentVideoDriver() switch
+            {
+                "windows" => SdlVideoDriver.Windows,
+                "x11" => SdlVideoDriver.X11,
+                _ => SdlVideoDriver.Other,
+            };
+        }
+
+        public unsafe void Shutdown()
+        {
+            if (_selfGCHandle != default)
+            {
+                SDL.SDL_RemoveEventWatch(&EventWatch, (void*) GCHandle.ToIntPtr(_selfGCHandle));
+                _selfGCHandle.Free();
+                _selfGCHandle = default;
+            }
+
+            SDL.SDL_SetLogOutputFunction(null, null);
+
+            if (SDL.SDL_WasInit(0) != 0)
+            {
+                _sawmill.Debug("Terminating SDL3");
+                SDL.SDL_Quit();
+            }
+        }
+
+        public void FlushDispose()
+        {
+            // Not currently used
+        }
+
+        public void GLMakeContextCurrent(WindowReg? reg)
+        {
+            SDL.SDLBool res;
+            if (reg is Sdl3WindowReg sdlReg)
+                res = SDL.SDL_GL_MakeCurrent(sdlReg.Sdl3Window, sdlReg.GlContext);
+            else
+                res = SDL.SDL_GL_MakeCurrent(IntPtr.Zero, IntPtr.Zero);
+
+            if (!res)
+                _sawmill.Error("SDL_GL_MakeCurrent failed: {error}", SDL.SDL_GetError());
+        }
+
+        public void GLSwapInterval(WindowReg reg, int interval)
+        {
+            ((Sdl3WindowReg)reg).SwapInterval = interval;
+            SDL.SDL_GL_SetSwapInterval(interval);
+        }
+
+        public unsafe void* GLGetProcAddress(string procName)
+        {
+            return (void*) SDL.SDL_GL_GetProcAddress(procName);
+        }
+
+        public string GetDescription()
+        {
+            var version = SDL.SDL_GetVersion();
+
+            var major = SDL.SDL_VERSIONNUM_MAJOR(version);
+            var minor = SDL.SDL_VERSIONNUM_MINOR(version);
+            var micro = SDL.SDL_VERSIONNUM_MICRO(version);
+
+            var videoDriver = SDL.SDL_GetCurrentVideoDriver();
+            var revision = SDL.SDL_GetRevision();
+
+            return $"SDL {major}.{minor}.{micro} (rev: {revision}, video driver: {videoDriver})";
+        }
+
+        [UnmanagedCallersOnly(CallConvs = [typeof(CallConvCdecl)])]
+        private static unsafe void LogOutputFunction(
+            void* userdata,
+            int category,
+            SDL.SDL_LogPriority priority,
+            byte* message)
+        {
+            var obj = (Sdl3WindowingImpl) GCHandle.FromIntPtr((IntPtr)userdata).Target!;
+
+            var level = priority switch
+            {
+                SDL.SDL_LogPriority.SDL_LOG_PRIORITY_VERBOSE => LogLevel.Verbose,
+                SDL.SDL_LogPriority.SDL_LOG_PRIORITY_DEBUG => LogLevel.Debug,
+                SDL.SDL_LogPriority.SDL_LOG_PRIORITY_INFO => LogLevel.Info,
+                SDL.SDL_LogPriority.SDL_LOG_PRIORITY_WARN => LogLevel.Warning,
+                SDL.SDL_LogPriority.SDL_LOG_PRIORITY_ERROR => LogLevel.Error,
+                SDL.SDL_LogPriority.SDL_LOG_PRIORITY_CRITICAL => LogLevel.Fatal,
+                _ => LogLevel.Error
+            };
+
+            var msg = Marshal.PtrToStringUTF8((IntPtr) message) ?? "";
+            var categoryName = SdlLogCategoryName(category);
+            obj._sawmillSdl3.Log(level, $"[{categoryName}] {msg}");
+        }
+
+        private static string SdlLogCategoryName(int category)
+        {
+            return (SDL.SDL_LogCategory) category switch {
+                // @formatter:off
+                SDL.SDL_LogCategory.SDL_LOG_CATEGORY_APPLICATION => "application",
+                SDL.SDL_LogCategory.SDL_LOG_CATEGORY_ERROR       => "error",
+                SDL.SDL_LogCategory.SDL_LOG_CATEGORY_ASSERT      => "assert",
+                SDL.SDL_LogCategory.SDL_LOG_CATEGORY_SYSTEM      => "system",
+                SDL.SDL_LogCategory.SDL_LOG_CATEGORY_AUDIO       => "audio",
+                SDL.SDL_LogCategory.SDL_LOG_CATEGORY_VIDEO       => "video",
+                SDL.SDL_LogCategory.SDL_LOG_CATEGORY_RENDER      => "render",
+                SDL.SDL_LogCategory.SDL_LOG_CATEGORY_INPUT       => "input",
+                SDL.SDL_LogCategory.SDL_LOG_CATEGORY_TEST        => "test",
+                _                            => "unknown"
+                // @formatter:on
+            };
+        }
+
+        private enum SdlVideoDriver
+        {
+            // These are the ones we need to be able to check against.
+            Other,
+            Windows,
+            X11
+        }
+    }
+}

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

@@ -2,7 +2,10 @@
 using System.Runtime.InteropServices;
 using Robust.Shared;
 using Robust.Shared.Configuration;
+using Robust.Shared.Utility;
 using TerraFX.Interop.Windows;
+using TerraFX.Interop.Xlib;
+using X11Window = TerraFX.Interop.Xlib.Window;
 
 namespace Robust.Client.Graphics.Clyde;
 
@@ -33,6 +36,8 @@ internal partial class Clyde
 
         public static unsafe void WindowsSharedWindowCreate(HWND hWnd, IConfigurationManager cfg)
         {
+            // TODO: REMOVE, only used by GLFW, SDL3 does DWMWA_USE_IMMERSIVE_DARK_MODE automatically.
+
             // >= Windows 11 22000 check
             if (cfg.GetCVar(CVars.DisplayWin11ImmersiveDarkMode) && Environment.OSVersion.Version.Build >= 22000)
             {
@@ -40,5 +45,37 @@ internal partial class Clyde
                 Windows.DwmSetWindowAttribute(hWnd, 20, &b, (uint) sizeof(BOOL));
             }
         }
+
+        public static void SetWindowStyleNoTitleOptionsWindows(HWND hWnd)
+        {
+            DebugTools.Assert(hWnd != HWND.NULL);
+
+            Windows.SetWindowLongPtrW(
+                hWnd,
+                GWL.GWL_STYLE,
+                // Cast to long here to work around a bug in rider with nint bitwise operators.
+                (nint)((long)Windows.GetWindowLongPtrW(hWnd, GWL.GWL_STYLE) & ~WS.WS_SYSMENU));
+        }
+
+        public static unsafe void SetWindowStyleNoTitleOptionsX11(Display* x11Display, X11Window x11Window)
+        {
+            DebugTools.Assert(x11Window != X11Window.NULL);
+            // https://specifications.freedesktop.org/wm-spec/wm-spec-latest.html#idm46181547486832
+            var newPropValString = Marshal.StringToCoTaskMemUTF8("_NET_WM_WINDOW_TYPE_DIALOG");
+            var newPropVal = Xlib.XInternAtom(x11Display, (sbyte*)newPropValString, Xlib.False);
+            DebugTools.Assert(newPropVal != Atom.NULL);
+
+            var propNameString = Marshal.StringToCoTaskMemUTF8("_NET_WM_WINDOW_TYPE");
+#pragma warning disable CA1806
+            // [display] [window] [property] [type] [format (8, 16,32)] [mode] [data] [element count]
+            Xlib.XChangeProperty(x11Display, x11Window,
+                Xlib.XInternAtom(x11Display, (sbyte*)propNameString, Xlib.False), // should never be null; part of spec
+                Xlib.XA_ATOM, 32, Xlib.PropModeReplace,
+                (byte*)&newPropVal, 1);
+#pragma warning restore CA1806
+
+            Marshal.FreeCoTaskMem(newPropValString);
+            Marshal.FreeCoTaskMem(propNameString);
+        }
     }
 }

Robust.Client/Graphics/IClyde.cs

@@ -133,29 +133,5 @@ namespace Robust.Client.Graphics
         IEnumerable<IClydeMonitor> EnumerateMonitors();
 
         IClydeWindow CreateWindow(WindowCreateParameters parameters);
-
-        /// <summary>
-        /// Set the active text input area in window pixel coordinates.
-        /// </summary>
-        /// <param name="rect">
-        /// This information is used by the OS to position overlays like IMEs or emoji pickers etc.
-        /// </param>
-        void TextInputSetRect(UIBox2i rect);
-
-        /// <summary>
-        /// Indicate that the game should start accepting text input on the currently focused window.
-        /// </summary>
-        /// <remarks>
-        /// On some platforms, this will cause an on-screen keyboard to appear.
-        /// The game will also start accepting IME input if configured by the user.
-        /// </remarks>
-        /// <seealso cref="TextInputStop"/>
-        void TextInputStart();
-
-        /// <summary>
-        /// Stop text input, opposite of <see cref="TextInputStart"/>.
-        /// </summary>
-        /// <seealso cref="TextInputStart"/>
-        void TextInputStop();
     }
 }

Robust.Client/Graphics/IClydeInternal.cs

@@ -69,5 +69,7 @@ namespace Robust.Client.Graphics
         void ShutdownGridEcsEvents();
 
         void RunOnWindowThread(Action action);
+
+        IFileDialogManager? FileDialogImpl { get; }
     }
 }

Robust.Client/Graphics/IClydeWindow.cs

@@ -41,6 +41,30 @@ namespace Robust.Client.Graphics
         /// Raised when the window has been resized.
         /// </summary>
         event Action<WindowResizedEventArgs> Resized;
+
+        /// <summary>
+        /// Set the active text input area in window pixel coordinates.
+        /// </summary>
+        /// <param name="rect">
+        /// This information is used by the OS to position overlays like IMEs or emoji pickers etc.
+        /// </param>
+        void TextInputSetRect(UIBox2i rect, int cursor);
+
+        /// <summary>
+        /// Indicate that the game should start accepting text input on the currently focused window.
+        /// </summary>
+        /// <remarks>
+        /// On some platforms, this will cause an on-screen keyboard to appear.
+        /// The game will also start accepting IME input if configured by the user.
+        /// </remarks>
+        /// <seealso cref="TextInputStop"/>
+        void TextInputStart();
+
+        /// <summary>
+        /// Stop text input, opposite of <see cref="TextInputStart"/>.
+        /// </summary>
+        /// <seealso cref="TextInputStart"/>
+        void TextInputStop();
     }
 
     public interface IClydeWindowInternal : IClydeWindow

Robust.Client/UserInterface/Controls/LineEdit.cs

@@ -880,7 +880,7 @@ namespace Robust.Client.UserInterface.Controls
 
             if (Editable)
             {
-                _clyde.TextInputStart();
+                Root?.Window?.TextInputStart();
             }
 
             _focusedOnFrame = _timing.CurFrame;
@@ -897,7 +897,8 @@ namespace Robust.Client.UserInterface.Controls
 
             OnFocusExit?.Invoke(new LineEditEventArgs(this, _text));
 
-            _clyde.TextInputStop();
+            Root?.Window?.TextInputStop();
+
             AbortIme(delete: false);
         }
 
@@ -1145,15 +1146,16 @@ namespace Robust.Client.UserInterface.Controls
                             contentBox.Bottom),
                         cursorColor);
 
+                    if (Root?.Window is { } window)
                     {
                         // Update IME position.
                         var imeBox = new UIBox2(
-                            actualCursorPosition,
+                            contentBox.Left,
                             contentBox.Top,
                             contentBox.Right,
                             contentBox.Bottom);
 
-                        _master._clyde.TextInputSetRect((UIBox2i) imeBox.Translated(GlobalPixelPosition));
+                        window.TextInputSetRect((UIBox2i) imeBox.Translated(GlobalPixelPosition), actualCursorPosition);
                     }
                 }
 

Robust.Client/UserInterface/Controls/TextEdit.cs

@@ -1366,15 +1366,16 @@ public sealed class TextEdit : Control
                             baseLine.Y + descent),
                         cursorColor);
 
-                    if (UserInterfaceManager.KeyboardFocused == _master)
+                    if (UserInterfaceManager.KeyboardFocused == _master && Root?.Window is { } window)
                     {
                         var box = (UIBox2i)new UIBox2(
-                            baseLine.X,
+                            drawBox.Left,
                             baseLine.Y - height + descent,
                             drawBox.Right,
                             baseLine.Y + descent);
+                        var cursorOffset = baseLine.X - drawBox.Left;
 
-                        _master._clyde.TextInputSetRect(box.Translated(GlobalPixelPosition));
+                        window.TextInputSetRect(box.Translated(GlobalPixelPosition), (int) cursorOffset);
                     }
                 }
 
@@ -1446,7 +1447,7 @@ public sealed class TextEdit : Control
 
         if (Editable)
         {
-            _clyde.TextInputStart();
+            Root?.Window?.TextInputStart();
         }
     }
 
@@ -1454,7 +1455,7 @@ public sealed class TextEdit : Control
     {
         base.KeyboardFocusExited();
 
-        _clyde.TextInputStop();
+        Root?.Window?.TextInputStop();
         AbortIme(delete: false);
     }
 

Robust.Client/UserInterface/FileDialogManager.cs

@@ -32,6 +32,9 @@ namespace Robust.Client.UserInterface
 
         public async Task<Stream?> OpenFile(FileDialogFilters? filters = null)
         {
+            if (_clyde.FileDialogImpl is { } clydeImpl)
+                return await clydeImpl.OpenFile(filters);
+
             var name = await GetOpenFileName(filters);
             if (name == null)
             {
@@ -53,6 +56,9 @@ namespace Robust.Client.UserInterface
 
         public async Task<(Stream, bool)?> SaveFile(FileDialogFilters? filters, bool truncate = true)
         {
+            if (_clyde.FileDialogImpl is { } clydeImpl)
+                return await clydeImpl.SaveFile(filters);
+
             var name = await GetSaveFileName(filters);
             if (name == null)
             {

Robust.Shared/ContentPack/Sandbox.yml

@@ -1197,6 +1197,7 @@ Types:
     RuntimeFieldHandle: { }
     RuntimeMethodHandle: { }
     RuntimeTypeHandle: { }
+    STAThreadAttribute: { All: True }
     SByte: { All: True }
     Single: { All: True }
     Span`1: