protected override void OnRenderFrame(FrameEventArgs e)
{
GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
GL.Enable(EnableCap.Blend);
GL.BlendFunc(BlendingFactorSrc.One, BlendingFactorDest.DstAlpha);
GL.MatrixMode(MatrixMode.Modelview);
GL.LoadIdentity();
g2d.BeginRender();
// g2d.Graphics.FillEllipse(new SolidBrush(Color.Red), 400, 700, 50, 50);
// g2d.Graphics.DrawPolygon(new Pen(Color.Green, 4), new Point[]
// {
// new Point(400, 100), new Point(450, 200),
// new Point(300, 400), new Point(150, 150)
// });
FactoryScreen.Draw();
g2d.EndRender();
SwapBuffers();
}