obtaining full desktop screenshot from the GPU

Question

I have been using the Windows API\'s BitBlt function to perform the screen grab.

There are many drawbacks however:

1. DWM and Aero cause a

Answer 1

OpenGL can only read the context framebuffer (a window), and any framebuffers or pbuffers you have created. OpenGL cannot touch the desktop or any other window.

Answer 2

This is an interesting question. Unfortunately I don't think this is really supported. I have found reports of some level of success with creating a full screen invisible window and reading the pixel data with glReadPixels:

http://www.virtualdub.org/blog/pivot/entry.php?id=142

http://www.opentk.com/node/2430

However, I believe the behavior when doing this is undefined and will only work on specific hardware/OS configurations.