Sample code for displaying RGBAZ images


i need some (working) sample code for displaying RGB+A+Z images. I get images from a raytracer including alpha + depth. What I want to do is:

  1. Mix multiple images (of course this can be done before sending the image to the open gl hardware - but it would be nice to do this by the graphic card)

  2. Mix the scene with realtime stuff - that means that the image should be used as background (i have a camera position and the look at postiion from the raytracer).

Any hint would be great. I played around with zcomposite.c (a GLUT example) but this just crashes on linux.

Any help would be very great.