On Linux how can I capture the desktop to an OpenGL texture?

Question

I'm writing a cross platform open source Oculus Rift desktop viewer. I decided to start with Linux because I prefer developing on it. I've already got the texture warping working but now I need to capture the desktop to an OpenGL texture. There are other issues I'm not entirely sure how to resolve like rendering the warped desktop to my window while capturing every window except mine. Any clue how I would go about this?

Answer 1

I think your best course of action would be actually to write a fully fledged compositor.

There is the GLX_texture_from_pixmap extension, that allows you to source any pixmap compatible X11 drawable into a OpenGL texture. For a start it might be enough to simply pull the root window (pixmap) as it is into a OpenGL texture. Later you might want to use the Composite extension to redirect windows to off-screen rendering and composite them in 3D space as a stereoscopic picture in the Occulus Rift.