function MetallicRoughness() {
  /**
   * The base color texture reader.
   *
   * @type {ModelComponents.TextureReader}
   * @private
   */
  this.baseColorTexture = undefined;

  /**
   * The metallic roughness texture reader.
   *
   * @type {ModelComponents.TextureReader}
   * @private
   */
  this.metallicRoughnessTexture = undefined;

  /**
   * The base color factor.
   *
   * @type {Cartesian4}
   * @default new Cartesian4(1.0, 1.0, 1.0, 1.0)
   * @private
   */
  this.baseColorFactor = Cartesian4.clone(
    MetallicRoughness.DEFAULT_BASE_COLOR_FACTOR,
  );

  /**
   * The metallic factor.
   *
   * @type {number}
   * @default 1.0
   * @private
   */
  this.metallicFactor = MetallicRoughness.DEFAULT_METALLIC_FACTOR;

  /**
   * The roughness factor.
   *
   * @type {number}
   * @default 1.0
   * @private
   */
  this.roughnessFactor = MetallicRoughness.DEFAULT_ROUGHNESS_FACTOR;
}
Material properties for the PBR metallic roughness shading model.

@alias ModelComponents.MetallicRoughness
@constructor

@private