The past week has been spent on optimizing irradiance caching, reducing artifacts and trying other options such as ambient occlusion. Irradiance caching was accelerated further during the past week by around 5 times, and the small scanline-like artifacts have been significantly reduced although there are still block artifacts. The blocks were removed by implementing a "Behind Test" as described by Ward in his SIGGRAPH course. I also tried other options during the week such as ambient occlusion and sun light imitation. In scenes such as Sponza where color bleeding does not happen a lot, ambient occlusion usually provides a pretty good estimate for the indirect illumination, and I would like to further explore the possibilities of combining ambient occlusion with irradiance caching in the coming week. I will keep you posted.
The first is a video showcasing the status of the renderer with irradiance caching:
Then we have a screen shot of the ambient occlusion computed result. Finally there's a video showing the performance of ambient occlusion.