jtBaseApp/node_modules/@cesium/engine/Source/Scene/DirectionalLight.js

import Cartesian3 from "../Core/Cartesian3.js";
import Check from "../Core/Check.js";
import Color from "../Core/Color.js";
import defaultValue from "../Core/defaultValue.js";
import DeveloperError from "../Core/DeveloperError.js";

/**
 * A light that gets emitted in a single direction from infinitely far away.
 *
 * @param {object} options Object with the following properties:
 * @param {Cartesian3} options.direction The direction in which light gets emitted.
 * @param {Color} [options.color=Color.WHITE] The color of the light.
 * @param {number} [options.intensity=1.0] The intensity of the light.
 *
 * @exception {DeveloperError} options.direction cannot be zero-length
 *
 * @alias DirectionalLight
 * @constructor
 */
function DirectionalLight(options) {
  //>>includeStart('debug', pragmas.debug);
  Check.typeOf.object("options", options);
  Check.typeOf.object("options.direction", options.direction);
  if (Cartesian3.equals(options.direction, Cartesian3.ZERO)) {
    throw new DeveloperError("options.direction cannot be zero-length");
  }
  //>>includeEnd('debug');

  /**
   * The direction in which light gets emitted.
   * @type {Cartesian3}
   */
  this.direction = Cartesian3.clone(options.direction);

  /**
   * The color of the light.
   * @type {Color}
   * @default Color.WHITE
   */
  this.color = Color.clone(defaultValue(options.color, Color.WHITE));

  /**
   * The intensity of the light.
   * @type {number}
   * @default 1.0
   */
  this.intensity = defaultValue(options.intensity, 1.0);
}

export default DirectionalLight;