Calculating ambient light.
I had an idea a little while ago for calculateing the ambient lighting term, but i'm not sure how well it would work in practice.
Suppose in my lighting system, i'm rendering the scene to a texture every frame to use HDR rendering, or some other technique that uses video post-processing.
Now, up untill now i've been just using a static value (usually zero) for the ambient term. But , if I were to get the average color from my scene texture, would this not be a more accurate ambient light value? To me (in theory of course), it sounds like using the average screen color as the ambient term would be able to emulate global indirect lighting.
This is probably not an original idea, but I haven't heard of it.
Is there any chance it could work, or does this idea break down when put into practice?