1e43f0d742
There were multiple issues which are solved now: - It was possible that ray wouldn't be bounced off the BSSRDF, for example when PDF or shader eval is zero. In this case PathState might have been left in pre-bounced state which would have been gave incorrect shading results. This is solved by having separate PathState for each of the hits. - Path radiance summing wasn't happening correct as well, indirect rays were using wrong path radiance in the case when there were more than one hit recorded. This is now using a bit trickier state machine which calculates path radiance for just SSS (both direct and indirect) and then sums it back to the final radiance. - Previous commit wasn't totally correct either and was an induced bug due to wrong path state left from the "un-happened" ray bounce. There should be no special case happening here, BSSRDFs will be replaced with diffuse ones due to PATH_RAY_DIFFUSE_ANCESTOR flag. - Merged back codebases for "delayed" and "immediate" indirect SSS ray tracing, hopefully making it easier to maintain the codebase. Sure this changes brings memory usage back by about 4-5%, but overall it's still about 2x memory reduction for the experimental kernel here. Thanks Brecht for the review!