Direct Light Sampling Cache errors

[lacilaci]

here, isolated issue (it seems like sky reflection is the problem)
hdri works normally, sky and sun works only if sky is not visible for glossy rays
If I add sun to hdri the issue appears again

[Dade]

If I add sun to hdri the issue appears again

Yes, like I said, it is a MIS problem: if you set max path depth to 1 (in .cfg file), it works fine, if set to 2 (MIS enabled), it doesn't. It happens because some cache entry, near a shadow boundary, has 2 entries (sun+sky) others has sky only (sun always not visible there). This change the weights of MIS and triggers the problem.

It should be possible to recreate the problem also with just 2 area lights (i.e. it is not related the light source types but to Glossy code for Sample() and Evaluate()).

[lacilaci]

If I add sun to hdri the issue appears again

Yes, like I said, it is a MIS problem: if you set max path depth to 1 (in .cfg file), it works fine, if set to 2 (MIS enabled), it doesn't. It happens because some cache entry, near a shadow boundary, has 2 entries (sun+sky) others has sky only (sun always not visible there). This change the weights of MIS and triggers the problem.

It should be possible to recreate the problem also with just 2 area lights (i.e. it is not related the light source types but to Glossy code for Sample() and Evaluate()).

When corona was introducing for the first time their new light solver that also handles many lights scenarios well. They too had similar issue I think: https://corona-renderer.com/forum/index ... #msg132828