// Overridable methods for derived controls

	// Called after succesful OpenGL initialization
	virtual void GLInit();

	// Called just before OpenGL termination
	virtual void GLDone();

	// Called on resize events
	virtual void GLResize(int w, int h);

	// Called on paint events
	virtual void GLPaint();

GUI_APP_MAIN{
    TopWindow win;
    MyGL gl;
    win.Add(gl.LeftPos(10, 700).TopPos(10, 700));
    win.Sizeable().Zoomable();
    win.Open();
    win.Run();
}