public MaterialSpecularMapFeature(IColorShader specularMap)
 {
     SpecularMap = specularMap;
 }
 public MaterialDiffuseMapFeature(IColorShader diffuseMap)
 {
     DiffuseMap = diffuseMap;
 }
 public MaterialNormalMapFeature(IColorShader normalMap)
 {
     NormalMap = normalMap;
 }