https://bugs.freedesktop.org/show_bug.cgi?id=34495
--- Comment #31 from Pierre-Eric Pelloux-Prayer pelloux@gmail.com 2011-07-01 10:33:20 PDT --- (In reply to comment #29)
More food for thought:
Using an fbo which is bigger than 1x1 is a waste of space since we only want to know Z values. Using a 32x32 fbo with some custom shaders we could handle 32*32 entries and so on.
With some more shader magic maybe we could have the left half of the fbo for minZ values and the other half for maxZ values?
Am I dreaming or is this doable?
I tried smaller FBO (8x8 I think), but the selection in Blender worked less reliably. But maybe that was related to wrong Z values being returned, and thus causing problem to Blender's selection algorithm. And, using 2 FBO might not be that expensive 1) if they are small 2) if state changes and read back are batched But I'm far from being an expert, so I guess we'll need to build it first to see if how well it performs.
Thanks for the help !