There's actually a lot of code involved in checking if all textures use
the same transform or coordinate set, especially when considering all
fallback variants and potential future expansion with separate texture
offset/scale/rotation attributes.
A lot of the complexity was thus hidden in plugin implementations, which
were each trying to find a common value for all textures to save the
user from doing the same. All that code can now be removed and left up
to the material APIs themselves -- now it's just about checking
hasCommonTextureTransformation() and then retrieving that one common
transformation, independently on how the material actually defines it.
This is a bit huge because of all the new overloads that take a
MaterialLayer instead of a string, but all that is just boring
boilerplate. Additionally this:
* exposes glTF clear coat parameters (which, interestingly enough,
reuse existing attributes and don't introduce any new)
* provides a convenience wrapper in PbrClearCoatMaterialData
* and a convenience base for material layer wrappers that redirect
all APIs with implicit layer argument to desired layer instead of the
base material
Vladimír Vondruš