[b]Note:[/b] This class is only compiled in editor builds. Run-time glTF loading and saving is [i]not[/i] available in exported projects. References to [GLTFSpecGloss] within a script will cause an error in an exported project. https://github.com/KhronosGroup/glTF/blob/main/extensions/2.0/Archived/KHR_materials_pbrSpecularGlossiness The reflected diffuse factor of the material. The diffuse texture. The glossiness or smoothness of the material. The specular-glossiness texture. The specular RGB color of the material. The alpha channel is unused.