Yeah, I work in the VFX industry, so I'm a bit biased :) Cool - actually, that would be a lot less computationally expensive (assuming you just modelled the su

Yeah, I work in the VFX industry, so I'm a bit biased :) Cool - actually, that would be a lot less computationally expensive (assuming you just modelled the sun as a disc) tracing it backwards without any GI at all. Photon mapping's pretty similar though, you've just got a final gather process at the end of sending out the light rays. The difference is photon mapping records all the hits to all surfaces. If you limited it to specular ones (at least for the first ray bounce) you'd probably have something very similar.