jtBaseApp/node_modules/cesium/Source/DataSources/MaterialProperty.js

import Color from "../Core/Color.js";
import defined from "../Core/defined.js";
import DeveloperError from "../Core/DeveloperError.js";
import Material from "../Scene/Material.js";

/**
 * The interface for all {@link Property} objects that represent {@link Material} uniforms.
 * This type defines an interface and cannot be instantiated directly.
 *
 * @alias MaterialProperty
 * @constructor
 * @abstract
 *
 * @see ColorMaterialProperty
 * @see CompositeMaterialProperty
 * @see GridMaterialProperty
 * @see ImageMaterialProperty
 * @see PolylineGlowMaterialProperty
 * @see PolylineOutlineMaterialProperty
 * @see StripeMaterialProperty
 */
function MaterialProperty() {
  DeveloperError.throwInstantiationError();
}

Object.defineProperties(MaterialProperty.prototype, {
  /**
   * Gets a value indicating if this property is constant.  A property is considered
   * constant if getValue always returns the same result for the current definition.
   * @memberof MaterialProperty.prototype
   *
   * @type {Boolean}
   * @readonly
   */
  isConstant: {
    get: DeveloperError.throwInstantiationError,
  },
  /**
   * Gets the event that is raised whenever the definition of this property changes.
   * The definition is considered to have changed if a call to getValue would return
   * a different result for the same time.
   * @memberof MaterialProperty.prototype
   *
   * @type {Event}
   * @readonly
   */
  definitionChanged: {
    get: DeveloperError.throwInstantiationError,
  },
});

/**
 * Gets the {@link Material} type at the provided time.
 * @function
 *
 * @param {JulianDate} time The time for which to retrieve the type.
 * @returns {String} The type of material.
 */
MaterialProperty.prototype.getType = DeveloperError.throwInstantiationError;

/**
 * Gets the value of the property at the provided time.
 * @function
 *
 * @param {JulianDate} time The time for which to retrieve the value.
 * @param {Object} [result] The object to store the value into, if omitted, a new instance is created and returned.
 * @returns {Object} The modified result parameter or a new instance if the result parameter was not supplied.
 */
MaterialProperty.prototype.getValue = DeveloperError.throwInstantiationError;

/**
 * Compares this property to the provided property and returns
 * <code>true</code> if they are equal, <code>false</code> otherwise.
 * @function
 *
 * @param {Property} [other] The other property.
 * @returns {Boolean} <code>true</code> if left and right are equal, <code>false</code> otherwise.
 */
MaterialProperty.prototype.equals = DeveloperError.throwInstantiationError;

/**
 * @private
 */
MaterialProperty.getValue = function (time, materialProperty, material) {
  let type;

  if (defined(materialProperty)) {
    type = materialProperty.getType(time);
    if (defined(type)) {
      if (!defined(material) || material.type !== type) {
        material = Material.fromType(type);
      }
      materialProperty.getValue(time, material.uniforms);
      return material;
    }
  }

  if (!defined(material) || material.type !== Material.ColorType) {
    material = Material.fromType(Material.ColorType);
  }
  Color.clone(Color.WHITE, material.uniforms.color);

  return material;
};
export default MaterialProperty;