code: function getMaterialData (data, materialData) {
    materialData.color.set(data.color);
    materialData.fog = data.fog;
    materialData.wireframe = data.wireframe;
    materialData.wireframeLinewidth = data.wireframeLinewidth;
    return materialData;
  }
docs: Builds and normalize material data, normalizing stuff along the way.
  
  @param {object} data - Material data.
  @param {object} materialData - Object to reuse.
  @returns {object} Updated material data.