I've implemented psm, I've read the big topic on psm in gamedev.net forum. I haven't understand why I've this sort o shadow artifacts ! I think that the motivation resides in the fact that the light frustum doesn't tightly enclose the unit cube, but I haven't found a way to calculate it. All the articles that I've write says: Now we have to compute the light frustum so that tightly enclose the unit cube. Ok but HOW ? Heeelp ! :D Thanks a lot for any suggestion !

That's the toughest part of PSMs.
The topic Shadow mapping in large environments discusses a 4 or 5 shadowmap PSM solution but it has its own problems.

Also if you've already implemented PSM then you definately want to take a look at the PSM article in the GPU Gems book IMO. It cleverly fixes some problems with the PSM approach described in the original paper. Even so I'd still recommend using something other than PSMs such as TSM or, the best IMO, multiple uniform shadow maps.

Quote:Original post by Soiled
That's the toughest part of PSMs.
The topic Shadow mapping in large environments discusses a 4 or 5 shadowmap PSM solution but it has its own problems.

Also if you've already implemented PSM then you definately want to take a look at the PSM article in the GPU Gems book IMO. It cleverly fixes some problems with the PSM approach described in the original paper. Even so I'd still recommend using something other than PSMs such as TSM or, the best IMO, multiple uniform shadow maps.

Thanks a lot for your reply. I've GPU gems but he doesn't discuss on how to calculate the light frustum so thigtly enclose the unit cube, instead talks about the problem of shadow caster behind the viewer an so on.

Anyway thank you !