I need to decide on a channel layout for PBR materials. There are four images to consider: metallic, roughness, occlusion, and height. These could be packed into a single RGBA texture. From the GLTF spec here: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#metallic-roughness-material I keep seeing people asserting that GLTF stores occlusion in the red channel, but the spec says it is a separate texture. So there does not seem to be any standard at all, as f