public void OnShow()
        {
            _contextPtr = OpenGl.GlXCreateContext(_window.NativeHandle, ref _visualInfo, IntPtr.Zero, true);
            OpenGl.GlXMakeCurrent(_window.NativeHandle, _window.WindowId, _contextPtr);

            WindowExtensions.LoadDefaultOpenGLFunctions();
        }
 public void Cleanup()
 {
     OpenGl.GlXMakeCurrent(_window.NativeHandle, 0, IntPtr.Zero);
     OpenGl.GlXDestroyContext(_window.NativeHandle, _contextPtr);
     WindowExtensions.Cleanup();
 }