Add PBR MTL spec document. Fixes #364

syoyo · syoyo · commit 22441b15f129 · 2023-06-20T21:05:20.000+09:00
diff --git a/README.md b/README.md
@@ -127,7 +127,7 @@ TinyObjLoader is successfully used in ...
 
 ### Material
 
-* PBR material extension for .MTL. Its proposed here: http://exocortex.com/blog/extending_wavefront_mtl_to_support_pbr
+* PBR material extension for .MTL. Please see [pbr-mtl.md](pbr-mtl.md) for details.
 * Texture options
 * Unknown material attributes are returned as key-value(value is string) map.
 
diff --git a/pbr-mtl.md b/pbr-mtl.md
@@ -0,0 +1,25 @@
+## PBR material extension.
+
+The spec can be found in internet archive: https://web.archive.org/web/20230210121526/http://exocortex.com/blog/extending_wavefront_mtl_to_support_pbr
+
+* Kd/map_Kd (base/diffuse) // reuse
+* Ks/map_Ks (specular) // reuse
+* d or Tr (opacity) // reuse
+* map_d/map_Tr (opacitymap) // reuse
+* Tf (translucency) // reuse
+* bump/-bm (bump map) // reuse
+* disp (displacement map) // reuse
+
+PBR material parameters as defined by the Disney PBR.
+
+* Pr/map_Pr (roughness) // new
+* Pm/map_Pm (metallic) // new
+* Ps/map_Ps (sheen) // new
+* Pc (clearcoat thickness) // new
+* Pcr (clearcoat roughness) // new
+* Ke/map_Ke (emissive) // new
+* aniso (anisotropy) // new
+* anisor (anisotropy rotation) // new
+* norm (normal map) // new
+
+EoL.
