gamnit :: MtlDef :: maps
map_diffuse, map_bump, map_specular, map_exponent
# Collect non-null maps from `map_diffuse, map_bump, map_specular, map_exponent` fun maps: Array[String] do return [for m in [map_ambient, map_diffuse, map_bump, map_specular, map_exponent] do if m != null then m] end