message: Use UberMaterial's roughness
diff: @@ -234,6 +234,8 @@ std::shared_ptr<sg::surface_properties> make_surface_properties(Shape::SP shape,
  obj->cd = vec3(m->kd.x, m->kd.y, m->kd.z);
  obj->cs = vec3(m->ks.x, m->ks.y, m->ks.z);
  + // TODO
  + obj->specular_exp = m->roughness;
  sp->material() = obj;
  add_diffuse_texture(sp, m->map_kd, base_filename);
  @@ -250,6 +252,8 @@ std::shared_ptr<sg::surface_properties> make_surface_properties(Shape::SP shape,
  obj->cd = vec3(m0->kd.x, m0->kd.y, m0->kd.z);
  obj->cs = vec3(m0->ks.x, m0->ks.y, m0->ks.z);
  + // TODO
  + obj->specular_exp = m0->roughness;
  sp->material() = obj;
  add_diffuse_texture(sp, m0->map_kd, base_filename);
  