2D In OpenGL

//#define MOUSECONTROL
#region using statements
using System;
using System.Drawing;
using OpenTK;
using OpenTK.Graphics;
using OpenTK.Math;
using OpenTK.Input;
#endregion
 
namespace OpenTKProject
{
    public class Game : GameWindow
    {
        #region Declarations
 
        const int InitialWidth = 1024;
        const int InitialHeight = 768;
 
        static float angle = 0;
        static float size = 25f;
 
        #endregion
 
        #region Constructor
        public Game()
            : base(InitialWidth, InitialHeight, new GraphicsMode(), "SquareDemo")
        { }
        #endregion
 
        #region Onload
        public override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);
 
            GL.ClearColor(Color.Black);
            GL.Enable(EnableCap.Blend);
            GL.Disable(EnableCap.DepthTest);
 
            GL.Viewport(0, 0, Width, Height);
            GL.MatrixMode(MatrixMode.Projection);
            GL.LoadIdentity();
            Glu.Ortho2D(0.0, (double)Width, 0.0, (double)Height);
        }
        #endregion
 
        #region OnResize
        protected override void OnResize(OpenTK.Platform.ResizeEventArgs e)
        {
            base.OnResize(e);
            GL.Viewport(0, 0, Width, Height);
            GL.MatrixMode(MatrixMode.Projection);
            GL.LoadIdentity();
            Glu.Ortho2D(0.0, (double)Width, 0.0, (double)Height);
        }
        #endregion
 
        #region OnUpdateFrame
        public override void OnUpdateFrame(UpdateFrameEventArgs e)
        {
            base.OnUpdateFrame(e);
 
#if MOUSECONTROL
            angle += Mouse.XDelta;            
            size += Mouse.WheelDelta;
#else
            angle = angle + 5;
#endif
 
            if (Keyboard[Key.Escape])
                Exit();
        }
        #endregion
 
        #region OnUnload
        public override void OnUnload(EventArgs e)
        {
            base.OnUnload(e);
        }
        #endregion
 
        #region OnRenderFrame
        public override void OnRenderFrame(RenderFrameEventArgs e)
        {
            base.OnRenderFrame(e);
 
            GL.Clear(ClearBufferMask.ColorBufferBit);
 
            GL.MatrixMode(MatrixMode.Modelview);
            GL.LoadIdentity();
 
            GL.Translate(350, 350, 0f);
 
            GL.PushMatrix();
            {
                GL.Rotate(angle, 0, 0, 1);
                GL.Color4(0.7, 0.5, 0.2, 0.5);
                GL.Begin(BeginMode.Quads);
                drawSquare();
                GL.End();
            }
            GL.PopMatrix();
 
            GL.PushMatrix();
            {
                GL.Translate(20, 50, 0);
                GL.Rotate(angle, 0, 0, 1);
                GL.Color4(0.2, 0.7, 0.4, 0.5);
                GL.Begin(BeginMode.LineLoop);
                drawSquare();
                GL.End();
            }
            GL.PopMatrix();
 
            SwapBuffers();
        }
 
        private static void drawSquare()
        {
            GL.Vertex2(-size, -size);
            GL.Vertex2(size, -size);
            GL.Vertex2(size, size);
            GL.Vertex2(-size, size);
        }
        #endregion
 
    }
 
    class Program
    {
        [STAThread]
        static void Main()
        {
            using (Game game = new Game())
            {
                game.Run(30, 30);
            }
 
        }
    }
}