Is there any way to retrieve (and modify) the back buffer (ala doublebuffer) after it has been rendered but before its been displayed?
Yes there is when you use double buffering !
If you use glReadPixels/glDrawPixels after having rendered your scene but before calling wglSwapBuffers, you will be able to do exactly what you describe…
Regards.
Eric
[This message has been edited by Eric (edited 12-18-2000).]