feat(renderer): a matte variant of a material for the parts of rails no wheel rolls on: it lights the same maps as weathered steel, with the weathering scaled per vertex by userdata, so a polished running surface fades into unused steel without a bright stripe; the cut faces of rails are drawn in it in an extra pass

rendering/renderer.h

@@ -69,6 +69,8 @@ public:
     virtual auto Fetch_Material( std::string const &Filename, bool const Loadnow = true ) -> material_handle = 0;
     virtual void Bind_Material( material_handle const Material, TSubModel const *sm = nullptr, lighting_data const *lighting = nullptr ) = 0;
     virtual auto Material( material_handle const Material ) const -> IMaterial const * = 0;
+    // the same material with its highlights damped, for faces which aren't polished like the surfaces they are cut from. backends which can't make one give back the material itself
+    virtual auto Matte_Material( material_handle const Material ) -> material_handle { return Material; }
     // heightmap terrain: material of a chunk blending the materials of up to 8 layers by their weights.
     // Weights: (Samples + 1)^2 values per layer, planar, rows of growing z, the weights of a sample adding up to 255; null with a single layer.
     // Placement: corner of the chunk (x, z) in the texture coordinates of its mesh, and the size of the chunk.