Fix blurry window on native Wayland

Author: Maia-Everett

src/XIVLauncher.Core/DesktopEnvironment/SdlHelpers.cs

@@ -1,7 +1,9 @@
 using System.Numerics;
 using System.Runtime.InteropServices;
 using System.Text;
+
 using Serilog;
+
 using Veldrid.Sdl2;
 
 namespace XIVLauncher.Core.DesktopEnvironment;
@@ -21,6 +23,11 @@ internal static unsafe partial class SdlHelpers
     private static int SDL_GetDisplayDPI(int displayIndex, float* ddpi, float* hdpi, float* vdpi)
         => s_sdl_getDisplayDPI(displayIndex, ddpi, hdpi, vdpi);
 
+    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+    private delegate void SDL_GL_GetDrawableSize_t(SDL_Window SDL2Window, int* w, int* h);
+    private static SDL_GL_GetDrawableSize_t s_getDrawableSize = Sdl2Native.LoadFunction<SDL_GL_GetDrawableSize_t>("SDL_GL_GetDrawableSize");
+    private static void SDL_GL_GetDrawableSize(SDL_Window Sdl2Window, int* w, int* h) => s_getDrawableSize(Sdl2Window, w, h);
+
     private static unsafe string GetString(byte* stringStart)
     {
         int characters = 0;
@@ -51,4 +58,11 @@ public static Vector2 GetDisplayDpiScale()
         Log.Verbose("SDL reports {0}x{1} DPI", hdpi, vdpi);
         return new Vector2(hdpi / 96, vdpi / 96);
     }
+
+    public static Vector2 GetWindowScale(Sdl2Window window)
+    {
+        int width, height;
+        SDL_GL_GetDrawableSize(window.SdlWindowHandle, &width, &height);
+        return new Vector2((float)width / window.Width, (float)height / window.Height);
+    }
 }

src/XIVLauncher.Core/DesktopEnvironment/XLVeldridStartup.cs

@@ -0,0 +1,88 @@
+using Veldrid;
+using Veldrid.Sdl2;
+using Veldrid.StartupUtilities;
+
+namespace XIVLauncher.Core.DesktopEnvironment;
+
+// Patched piece of VeldridStartup to pass SDL_WindowFlags.AllowHighDpi to SDL_CreateWindow
+public static class XLVeldridStartup
+{
+    public static void CreateWindowAndGraphicsDevice(
+        WindowCreateInfo windowCI,
+        out Sdl2Window window,
+        out GraphicsDevice gd)
+        => CreateWindowAndGraphicsDevice(
+            windowCI,
+            new GraphicsDeviceOptions(),
+            VeldridStartup.GetPlatformDefaultBackend(),
+            out window,
+            out gd);
+
+    public static void CreateWindowAndGraphicsDevice(
+        WindowCreateInfo windowCI,
+        GraphicsDeviceOptions deviceOptions,
+        out Sdl2Window window,
+        out GraphicsDevice gd)
+        => CreateWindowAndGraphicsDevice(windowCI, deviceOptions, VeldridStartup.GetPlatformDefaultBackend(), out window, out gd);
+
+    public static void CreateWindowAndGraphicsDevice(
+        WindowCreateInfo windowCI,
+        GraphicsDeviceOptions deviceOptions,
+        GraphicsBackend preferredBackend,
+        out Sdl2Window window,
+        out GraphicsDevice gd)
+    {
+        Sdl2Native.SDL_Init(SDLInitFlags.Video);
+        if (preferredBackend == GraphicsBackend.OpenGL || preferredBackend == GraphicsBackend.OpenGLES)
+        {
+            VeldridStartup.SetSDLGLContextAttributes(deviceOptions, preferredBackend);
+        }
+
+        window = CreateWindow(ref windowCI);
+        gd = VeldridStartup.CreateGraphicsDevice(window, deviceOptions, preferredBackend);
+    }
+
+
+    public static Sdl2Window CreateWindow(WindowCreateInfo windowCI) => CreateWindow(ref windowCI);
+
+    public static Sdl2Window CreateWindow(ref WindowCreateInfo windowCI)
+    {
+        SDL_WindowFlags flags = SDL_WindowFlags.OpenGL | SDL_WindowFlags.Resizable | SDL_WindowFlags.AllowHighDpi
+                | GetWindowFlags(windowCI.WindowInitialState);
+        if (windowCI.WindowInitialState != WindowState.Hidden)
+        {
+            flags |= SDL_WindowFlags.Shown;
+        }
+        Sdl2Window window = new Sdl2Window(
+            windowCI.WindowTitle,
+            windowCI.X,
+            windowCI.Y,
+            windowCI.WindowWidth,
+            windowCI.WindowHeight,
+            flags,
+            false);
+
+        return window;
+    }
+
+    private static SDL_WindowFlags GetWindowFlags(WindowState state)
+    {
+        switch (state)
+        {
+            case WindowState.Normal:
+                return 0;
+            case WindowState.FullScreen:
+                return SDL_WindowFlags.Fullscreen;
+            case WindowState.Maximized:
+                return SDL_WindowFlags.Maximized;
+            case WindowState.Minimized:
+                return SDL_WindowFlags.Minimized;
+            case WindowState.BorderlessFullScreen:
+                return SDL_WindowFlags.FullScreenDesktop;
+            case WindowState.Hidden:
+                return SDL_WindowFlags.Hidden;
+            default:
+                throw new VeldridException("Invalid WindowState: " + state);
+        }
+    }
+}

src/XIVLauncher.Core/Program.cs

@@ -265,16 +265,22 @@ private static void Main(string[] args)
         var windowWidth = (int)ImGuiHelpers.GetScaled(1280);
         var windowHeight = (int)ImGuiHelpers.GetScaled(800);
 
-        VeldridStartup.CreateWindowAndGraphicsDevice(
+        XLVeldridStartup.CreateWindowAndGraphicsDevice(
             new WindowCreateInfo(50, 50, windowWidth, windowHeight, WindowState.Normal, $"XIVLauncher {version}"),
             new GraphicsDeviceOptions(false, null, true, ResourceBindingModel.Improved, true, true),
             out window,
             out gd);
 
+        var windowScale = SdlHelpers.GetWindowScale(window).Y;
+        ImGuiHelpers.GlobalScale *= windowScale;
+
         window.Resized += () =>
         {
-            gd.MainSwapchain.Resize((uint)window.Width, (uint)window.Height);
-            bindings.WindowResized(window.Width, window.Height);
+            var scaledWidth = (int)Math.Round(window.Width * windowScale);
+            var scaledHeight = (int)Math.Round(window.Height * windowScale);
+
+            gd.MainSwapchain.Resize((uint)scaledWidth, (uint)scaledHeight);
+            bindings.WindowResized(scaledWidth, scaledHeight);
             Invalidate();
         };
         cl = gd.ResourceFactory.CreateCommandList();