public X11GLContext(GraphicsMode mode, X11Window window)
        {
            Debug.Print("Creating X11GLContext context: ");
            cur = window;
            XVisualInfo info = cur.VisualInfo;

            // Cannot pass a Property by reference.
            IntPtr display = API.DefaultDisplay;

            ContextHandle = Glx.glXCreateContext(display, ref info, IntPtr.Zero, true);

            if (ContextHandle == IntPtr.Zero)
            {
                Debug.Print("failed. Trying indirect... ");
                ContextHandle = Glx.glXCreateContext(display, ref info, IntPtr.Zero, false);
            }

            if (ContextHandle != IntPtr.Zero)
            {
                Debug.Print("Context created (id: {0}).", ContextHandle);
            }
            else
            {
                throw new GraphicsContextException("Context creation failed. Error: NULL returned");
            }

            if (!Glx.glXIsDirect(display, ContextHandle))
            {
                Debug.Print("Warning: Context is not direct.");
            }
            if (!Glx.glXMakeCurrent(API.DefaultDisplay, window.WinHandle, ContextHandle))
            {
                throw new GraphicsContextException("Failed to make context current.");
            }

            Glx.LoadEntryPoints();
            vsync_supported = Glx.glXSwapIntervalSGI != null;
        }