Dual paraboloid shadowmaps were ending up with infinitely large volumes of area behind the hemisphere un-culled.
This change just adds a back plane to the convex shape used for the culling volume.
Also implemented decal atlas, so projectors and other stuff can be added.
Sidenote: Had to make RID hashable, so some unrelated includes changed
in order to include it in hashfuncs.h
- Made shadow bias size independent, so it will remain when changing light or camera size.
- Implemented normal offset bias, which greatly enhances quality.
- Added transmission to subsurface scattering
- Reimplemented shadow filter modes
Closes#17260
