Turns out whenever a normal prepass was active (which includes whenever
you use SSAO) we were attempting to read the normals from the prepass
for the specular transmissive material. Since transmissive materials
don't participate in the prepass (unlike opaque materials) we were
reading the normals from “behind” the mesh, producing really weird
visual results.
# Objective
- Fixes#11112.
## Solution
- We introduce a new `READS_VIEW_TRANSMISSION_TEXTURE` mesh pipeline
key;
- We set it whenever the material properties has the
`reads_view_transmission_texture` flag set; (i.e. the material is
transmissive)
- If this key is set we prevent the reading of normals from the prepass,
by not setting the `LOAD_PREPASS_NORMALS` shader def.
---
## Changelog
### Fixed
- Specular transmissive materials no longer attempt to erroneously load
prepass normals, and now work correctly even with the normal prepass
active (e.g. when using SSAO)
c2ab3a0402