Well, I know very little of OGL to be honest (only tried spinning cubes and whatnot) but AFAIK postprocessing is done via FBO:s which make use of a framebuffer? Or am I totally lost here? Anyways, from what I've gathered SCP couldn't do post processing due to the lack of a framebuffer.
Well, the mention of GLSL (I'm guessing shaders are a form of a post-process or am I totally lost again?) got me wondering, sorry for the 'derailing'.