How can I know which polygons have been rasterized
I am trying to work out which geometry actually makes the contribution to the final rendered image...for every frame. To be specific, I want to know from all the quads/triangles sent to OpenGL, which ones have actually made a pixel contribution.
I proposed to number (glPushName) every primitive and use selection/feedback, but that would be rather horrid. Performing ray to scene intersection tests seems like the next best thing. Knowing full well that I can't get access to the internals of the rasterisation stage (I believe DirectX 11 allows you to), how could I go about the task in the most effective way?
btw I am using:
OpenGL version string: 2.0 ATI-1.5.36 on OSX (ATI 1600x mobility).