Hello, i want to override the glutSwapBuffers () function to change several states before swapping the buffers after all. But I have to decide wether the callback function registered with glutReshapeFunc is called. I saw the callbak set within the glut-Library. But now i want to check wether the function was called in an if statement. How can I get the called function ?? My configuration: Linux, X11 My theory: - Use GLX to get the callback or - with GLUT Is anybody out there who can fix my problem ?? Thx a lot Nordberg p.s: sorry for my bad english ;-)