How do I alpha blend two PBOs?
I’ve been trying to use glBlitFramebuffer/glBlitFramebufferEXT to blend 2 PBOs, but I’m not having any luck. I get a complete overwrite of one on top of the other with no blending. Does glBlitFramebuffer alpha blend or am I flat-out using the wrong function?
My drawing to each of the individual PBO’s blends quite fine, so I’ve got blending enabled and the blend functions working (not exactly the way I want, but I can sort that out once I get something).
I’d really like not to have to use textures (although I will if that’s the only solution) as there seem to be way too many drivers requiring powers of two, and I’m at 2560x1600 which would require 4096x4096 textures of which most is wasted. Not to mention the strange issues with getting pixel accurate alignment.