materials

[Rismosch]

• have an array of textures
• have an array of materials
• material references texture by index
• shader references material by index

thus, to render a mesh with an associated material, a single int needs to be passed. this easily fits into a push constant

a texture/material would be similarily implemented like the mesh lookup. maybe this can be generalized.

[Rismosch]

a material would store:

• albedo/base color
• albedo/base map
• normal map
• metallic map (metallic is either 1 or 0, but allows a blend on transitions)
• roughness map

unassigned maps would have the index -1 and would use a default value

[Rismosch]

see glTF 2.0 spec page 176 "Appendix B: BRDF Implementation" for a PBR material model