The IOR impacts how much a single microfacet refracts incoming light. In turn this changes how “wide” the distribution of output ray directions is and how rough the BRDF should be. This function scales the roughness toward 0.0 as IOR tends towards 1.0, while leaving the default roughness for IOR = 1.5. Adapted from Khronos gltf-Sample-Renderer (https://github.com/KhronosGroup/glTF-Sample-Renderer/blob/bec106e53da4a6a398aa3205f0f96563519a657e/source/Renderer/shaders/functions.glsl#L84-L89)
Functions
The IOR impacts how much a single microfacet refracts incoming light. In turn this changes how “wide” the distribution of output ray directions is and how rough the BRDF should be. This function scales the roughness toward 0.0 as IOR tends towards 1.0, while leaving the default roughness for IOR = 1.5. Adapted from Khronos gltf-Sample-Renderer (https://github.com/KhronosGroup/glTF-Sample-Renderer/blob/bec106e53da4a6a398aa3205f0f96563519a657e/source/Renderer/shaders/functions.glsl#L84-L89)