[GLX] Try newer versions of OpenGL first

src/Avalonia.X11/Glx/Glx.cs

@@ -18,7 +18,10 @@ namespace Avalonia.X11.Glx
         
         [DllImport(libGL, EntryPoint = "glXCreateContext")]
         public static extern  IntPtr GlxCreateContext(IntPtr dpy,  XVisualInfo* vis,  IntPtr shareList,  bool direct);
-        
+
+        [DllImport(libGL, EntryPoint = "glXCreateContextAttribsARB")]
+        public static extern IntPtr GlxCreateContextAttribsARB(IntPtr dpy, IntPtr fbconfig, IntPtr shareList,
+            bool direct, int[] attribs);
 
         [DllImport(libGL, EntryPoint = "glXGetProcAddress")]
         public static extern  IntPtr GlxGetProcAddress(Utf8Buffer buffer);

src/Avalonia.X11/Glx/GlxConsts.cs

@@ -93,5 +93,14 @@ namespace Avalonia.X11.Glx
         public const int GLX_SAMPLES = 0x186a1 /*100001*/;
         public const int GLX_PbufferClobber = 0;
         public const int GLX_BufferSwapComplete = 1;
+        public const int GLX_CONTEXT_DEBUG_BIT_ARB = 0x00000001;
+        public const int GLX_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB = 0x00000002;
+        public const int GLX_CONTEXT_MAJOR_VERSION_ARB = 0x2091;
+        public const int GLX_CONTEXT_MINOR_VERSION_ARB = 0x2092;
+        public const int GLX_CONTEXT_FLAGS_ARB = 0x2094;
+        public const int GLX_CONTEXT_CORE_PROFILE_BIT_ARB = 0x00000001;
+        public const int GLX_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB = 0x00000002;
+        public const int GLX_CONTEXT_PROFILE_MASK_ARB = 0x9126;
+
     }
 }

src/Avalonia.X11/Glx/GlxDisplay.cs

@@ -89,10 +89,38 @@ namespace Avalonia.X11.Glx
         public GlxContext CreateContext(IGlContext share)
         {
             var sharelist = ((GlxContext)share)?.Handle ?? IntPtr.Zero;
-            var h = GlxCreateContext(_x11.Display, _visual, sharelist, true);
-            if (h == IntPtr.Zero)
+            IntPtr handle = default;
+            foreach (var ver in new[]
+            {
+                new Version(4, 0), new Version(3, 2),
+                new Version(3, 0), new Version(2, 0)
+            })
+            {
+
+                var attrs = new[]
+                {
+                    GLX_CONTEXT_MAJOR_VERSION_ARB, ver.Major,
+                    GLX_CONTEXT_MINOR_VERSION_ARB, ver.Minor,
+                    GLX_CONTEXT_PROFILE_MASK_ARB, GLX_CONTEXT_CORE_PROFILE_BIT_ARB,
+                    0
+                };
+                try
+                {
+                    handle = GlxCreateContextAttribsARB(_x11.Display, _fbconfig, sharelist, true, attrs);
+                    if (handle != IntPtr.Zero)
+                        break;
+                }
+                catch
+                {
+                    break;
+                }
+            }
+            
+            if(handle == IntPtr.Zero)
+                handle = GlxCreateContext(_x11.Display, _visual, sharelist, true);
+            if (handle == IntPtr.Zero)
                 throw new OpenGlException("Unable to create direct GLX context");
-            return new GlxContext(h, this, _x11);
+            return new GlxContext(handle, this, _x11);
         }
 
         public void SwapBuffers(IntPtr xid) => GlxSwapBuffers(_x11.Display, xid);