Implementing the KHR_materials_specular extension
In the previous chapter, we discussed the Specular-Glossiness PBR model. One of its main issues is the lack of compatibility with most other extensions. This is because it introduces non-physically based material properties, including an unclear distinction between dielectrics and metals in specular-glossiness mode, which makes it impossible to combine with the metallic-roughness model or other extension properties.
As an alternative, Khronos proposed the KHR_materials_specular extension, which addresses these issues and offers the functionality of KHR_materials_pbrSpecularGlossiness without compromising the physical accuracy of the Metallic-Roughness PBR model. This makes it compatible with most glTF PBR extensions. At the time of writing, the KHR_materials_specular extension is only incompatible with the KHR_materials_pbrSpecularGlossiness and KHR_materials_unlit extensions.
The KHR_materials_specular extension allows for more precise...
