Sometime ago I and my brother got an idea how to make post process reflection and we did some quick testing on it. We did it just for fun and now I'd like to hear if someone else wanted to test or use it.
What do I mean by post process reflection? It isn't reflection render. You still render with your 3D software but instead of rendering the reflections straight away you render the reflection ray directions. You can then quickly calculate the reflections from any environment map in post processing.
First you render this kind of refletion image.
Then you can change enviorment map on reflection with out render image again.
What you think about this system?
Do you know if this is already used somewhere?