fix: query GL_MAX_SAMPLES before setting multisampling hint

- adds better located exceptions to catch things like couldnt find matching glx visual" - creates and disposes of temporary gl-enabled window and gl context to grab GL_MAX_SAMPLES from
lodicolo · Oct 30, 2023 · c7dbee9 · c7dbee9
1 parent a91dcc7
commit c7dbee9
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Showing 3 changed files with 43 additions and 2 deletions.
diff --git a/MonoGame.Framework/Platform/Graphics/OpenGL.cs b/MonoGame.Framework/Platform/Graphics/OpenGL.cs
@@ -1258,6 +1258,15 @@ static void DebugMessageCallbackHandler(int source, int type, int id, int severi
 
         internal static int SwapInterval { get; set; }
 
+        internal unsafe static int GetMaxSamples()
+        {
+            GetIntegerv = LoadFunction<GetIntegerDelegate> ("glGetIntegerv");
+
+            int maxSamples = 0;
+            GetIntegerv((int)GetPName.MaxSamples, &maxSamples);
+            return maxSamples;
+        }
+
         internal static void LoadEntryPoints ()
         {
             LoadPlatformEntryPoints ();
@@ -1455,7 +1464,7 @@ internal static void LoadExtensions()
                 GL.LoadFrameBufferObjectEXTEntryPoints();
             }
             if (GL.RenderbufferStorageMultisample == null)
-            {                
+            {
                 if (Extensions.Contains("GL_APPLE_framebuffer_multisample"))
                 {
                     GL.RenderbufferStorageMultisample = LoadFunction<GL.RenderbufferStorageMultisampleDelegate>("glRenderbufferStorageMultisampleAPPLE");

diff --git a/MonoGame.Framework/Platform/GraphicsDeviceManager.SDL.cs b/MonoGame.Framework/Platform/GraphicsDeviceManager.SDL.cs
@@ -2,7 +2,9 @@
 // This file is subject to the terms and conditions defined in
 // file 'LICENSE.txt', which is part of this source code package.
 
+using System;
 using Microsoft.Xna.Framework.Graphics;
+using MonoGame.OpenGL;
 
 namespace Microsoft.Xna.Framework
 {
@@ -45,8 +47,24 @@ partial void PlatformInitialize(PresentationParameters presentationParameters)
 
             if (presentationParameters.MultiSampleCount > 0)
             {
+                var temporaryWindow = Sdl.Window.Create(
+                    "glContextInfoWindow",
+                    0,
+                    0,
+                    0,
+                    0,
+                    Sdl.Window.State.OpenGL |
+                    Sdl.Window.State.Hidden |
+                    Sdl.Window.State.InputFocus |
+                    Sdl.Window.State.MouseFocus
+                );
+                var temporaryGLContext = Sdl.GL.CreateContext(temporaryWindow);
+                var maxSamples = GL.GetMaxSamples();
+                Sdl.GL.DeleteContext(temporaryGLContext);
+                Sdl.Window.Destroy(temporaryWindow);
+
                 Sdl.GL.SetAttribute(Sdl.GL.Attribute.MultiSampleBuffers, 1);
-                Sdl.GL.SetAttribute(Sdl.GL.Attribute.MultiSampleSamples, presentationParameters.MultiSampleCount);
+                Sdl.GL.SetAttribute(Sdl.GL.Attribute.MultiSampleSamples, Math.Min(maxSamples, presentationParameters.MultiSampleCount));
             }
 
             ((SdlGameWindow)SdlGameWindow.Instance).CreateWindow();

diff --git a/MonoGame.Framework/Platform/SDL/SDLGameWindow.cs b/MonoGame.Framework/Platform/SDL/SDLGameWindow.cs
@@ -3,11 +3,13 @@
 // file 'LICENSE.txt', which is part of this source code package.
 
 using System;
+using System.Diagnostics;
 using System.IO;
 using System.Reflection;
 using Microsoft.Xna.Framework.Graphics;
 using Microsoft.Xna.Framework.Input;
 using MonoGame.Framework.Utilities;
+using MonoGame.OpenGL;
 
 namespace Microsoft.Xna.Framework
 {
@@ -133,6 +135,12 @@ public SdlGameWindow(Game game)
             _handle = Sdl.Window.Create("", 0, 0,
                 GraphicsDeviceManager.DefaultBackBufferWidth, GraphicsDeviceManager.DefaultBackBufferHeight,
                 Sdl.Window.State.Hidden | Sdl.Window.State.FullscreenDesktop);
+
+            if (_handle == default)
+            {
+                var sdlError = Sdl.GetError();
+                throw new NoSuitableGraphicsDeviceException(sdlError);
+            }
         }
 
         internal void CreateWindow()
@@ -164,6 +172,12 @@ internal void CreateWindow()
                 winx, winy, _width, _height, initflags
             );
 
+            if (_handle == default)
+            {
+                var sdlError = Sdl.GetError();
+                throw new NoSuitableGraphicsDeviceException(sdlError);
+            }
+
             Id = Sdl.Window.GetWindowId(_handle);
 
             if (_icon != IntPtr.Zero)