PBR Material Notes

• openGl spec Y+ normals
• alpha is embeded within the diffuse
• gloss maps are defined in UE4 style (black is matte, white is glossy)
• specular is typical across all PBR(defines % of light at f0 per channel)
• the only unique values are for gloss
• so we use the transparency channel in the DAE as the gloss, and blenders shininess float is 1-511
• only 2 uv layers are supported
• diffuse, normal, specular, gloss on layer 1, AO on layer 2
• blender outputs the ambient color as 0 0 0 by default