private void button1_Click(object sender, EventArgs e)
{
GL.Viewport(0, 0, Width, Height);
Matrix4 projection = Matrix4.CreatePerspectiveFieldOfView((float)System.Math.PI / 4, glControl1.Width / (float)Height, 1.0f, 64.0f);
GL.MatrixMode(MatrixMode.Projection);
GL.LoadMatrix(ref projection);
GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
Matrix4 modelview = Matrix4.LookAt(Vector3.Zero, Vector3.UnitZ, Vector3.UnitY);
GL.MatrixMode(MatrixMode.Modelview);
GL.LoadMatrix(ref modelview);
GL.Begin(BeginMode.Triangles);
GL.Color3(1.0f, 1.0f, 0.0f); GL.Vertex3(-1.0f, -1.0f, 4.0f);
GL.Color3(1.0f, 0.0f, 0.0f); GL.Vertex3(1.0f, -1.0f, 4.0f);
GL.Color3(0.2f, 0.9f, 1.0f); GL.Vertex3(0.0f, 1.0f, 4.0f);
GL.End();
glControl1.SwapBuffers();
}