3D window inside of a subform

    public class Viewport : Form
    {
 
        // PROPERTIES:
 
        private OpenTK.GLControl glControl1;
        private bool loaded = false;
 
 
        // METHODS:
 
        private void Viewport_Load(object sender, EventArgs e)
        {
            loaded = true;
            GL.ClearColor(Color.Black);
            SetupViewport();
        }
 
        private void SetupViewport()
        {
            int w = glControl1.Width;       
            int h = glControl1.Height;
 
            GL.MatrixMode(MatrixMode.Projection);
            GL.LoadIdentity();
            GL.Ortho(0, w, 0, h, -1, 1); // Bottom-left corner pixel has coordinate (0, 0)
            GL.Viewport(0, 0, w, h); // Use all of the glControl painting area
            GL.Enable(EnableCap.DepthTest);
        }
 
        private void glControl1_Resize(object sender, EventArgs e)
        {
            int myWidth = Width;
 
            if (!loaded)
                return;
 
            if (myWidth == 0)
                myWidth = 1;
 
            GL.MatrixMode(MatrixMode.Projection);
            GL.LoadIdentity();
 
            Glu.Perspective(45, 1.0, 0.1, 1000);
 
            GL.MatrixMode(MatrixMode.Modelview);
            GL.LoadIdentity();
        }
 
        // render the graphics in the viewport
        private void glControl1_Paint(object sender, PaintEventArgs e)
        {
            if (!loaded) // don't execute if not already loaded!
                return;
 
            GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
 
            GL.MatrixMode(MatrixMode.Modelview);
            GL.LoadIdentity();
 
            GL.Color3(Color.Yellow);            
            GL.PointSize(2.0f);
 
            GL.Begin(BeginMode.Points);
 
                GL.Vertex3(50.0, 50.0, 0.0);
                GL.Vertex3(60.0, 60.0, 0.5);
                GL.Vertex3(70.0, 70.0, 1.0);
                GL.Vertex3(80.0, 80.0, 1.1);
 
            GL.End();
 
            glControl1.SwapBuffers();
        }