This is a very specific question: I am looking to use normals in post processing. I have been looking at SSAO, but it seems slow and at low samples I don’t see good results.
At the moment I can use it for simple “lighting”, but I figure there should be more and better possibilities. So, anyone know of any postprocessing tricks with normal maps?
Edit: Bump maps I already know as well btw.
Edit2: I found a cheaper SSAO shader also, http://blenderartists.org/forum/showthread.php?184102-nicer-and-faster-SSAO
What exactly are you looking to do? Typically, the only post-processing to involve normal maps is deferred lighting.
You could, in theory, use the information to supplement bloom or almost any lighting-related post effect. Depth of field could benefit by using surface normals and brightness to calculate bokeh, you could use normals and specular for light glare. I’m sure there are other potential uses, and would experiment with them, especially if you have normal data lying around in a buffer from your lighting solution.