Parameters used to create the shader chunk.
OptionalextensionsUsed?: GLTFExtensionsUsedextensionsUsed to check if clearcoat is enabled.
OptionalenvironmentMap?: EnvironmentMapEnvironmentMap to use for GGX Fresnel if any.
clearcoatSpecularIndirect (vec3f) value set.
Get the clearcoat indirect radiance (specular) contribution as
clearcoatSpecularIndirect(vec3f).