Cesium-Prequel/Source/DataSources/ConstantPositionProperty.js

import Cartesian3 from "../Core/Cartesian3.js";
import defaultValue from "../Core/defaultValue.js";
import defined from "../Core/defined.js";
import DeveloperError from "../Core/DeveloperError.js";
import Event from "../Core/Event.js";
import ReferenceFrame from "../Core/ReferenceFrame.js";
import PositionProperty from "./PositionProperty.js";

/**
 * A {@link PositionProperty} whose value does not change in respect to the
 * {@link ReferenceFrame} in which is it defined.
 *
 * @alias ConstantPositionProperty
 * @constructor
 *
 * @param {Cartesian3} [value] The property value.
 * @param {ReferenceFrame} [referenceFrame=ReferenceFrame.FIXED] The reference frame in which the position is defined.
 */
function ConstantPositionProperty(value, referenceFrame) {
  this._definitionChanged = new Event();
  this._value = Cartesian3.clone(value);
  this._referenceFrame = defaultValue(referenceFrame, ReferenceFrame.FIXED);
}

Object.defineProperties(ConstantPositionProperty.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 ConstantPositionProperty.prototype
   *
   * @type {Boolean}
   * @readonly
   */
  isConstant: {
    get: function () {
      return (
        !defined(this._value) || this._referenceFrame === ReferenceFrame.FIXED
      );
    },
  },
  /**
   * 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 ConstantPositionProperty.prototype
   *
   * @type {Event}
   * @readonly
   */
  definitionChanged: {
    get: function () {
      return this._definitionChanged;
    },
  },
  /**
   * Gets the reference frame in which the position is defined.
   * @memberof ConstantPositionProperty.prototype
   * @type {ReferenceFrame}
   * @default ReferenceFrame.FIXED;
   */
  referenceFrame: {
    get: function () {
      return this._referenceFrame;
    },
  },
});

/**
 * Gets the value of the property at the provided time in the fixed frame.
 *
 * @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.
 */
ConstantPositionProperty.prototype.getValue = function (time, result) {
  return this.getValueInReferenceFrame(time, ReferenceFrame.FIXED, result);
};

/**
 * Sets the value of the property.
 *
 * @param {Cartesian3} value The property value.
 * @param {ReferenceFrame} [referenceFrame=this.referenceFrame] The reference frame in which the position is defined.
 */
ConstantPositionProperty.prototype.setValue = function (value, referenceFrame) {
  var definitionChanged = false;
  if (!Cartesian3.equals(this._value, value)) {
    definitionChanged = true;
    this._value = Cartesian3.clone(value);
  }
  if (defined(referenceFrame) && this._referenceFrame !== referenceFrame) {
    definitionChanged = true;
    this._referenceFrame = referenceFrame;
  }
  if (definitionChanged) {
    this._definitionChanged.raiseEvent(this);
  }
};

/**
 * Gets the value of the property at the provided time and in the provided reference frame.
 *
 * @param {JulianDate} time The time for which to retrieve the value.
 * @param {ReferenceFrame} referenceFrame The desired referenceFrame of the result.
 * @param {Cartesian3} [result] The object to store the value into, if omitted, a new instance is created and returned.
 * @returns {Cartesian3} The modified result parameter or a new instance if the result parameter was not supplied.
 */
ConstantPositionProperty.prototype.getValueInReferenceFrame = function (
  time,
  referenceFrame,
  result
) {
  //>>includeStart('debug', pragmas.debug);
  if (!defined(time)) {
    throw new DeveloperError("time is required.");
  }
  if (!defined(referenceFrame)) {
    throw new DeveloperError("referenceFrame is required.");
  }
  //>>includeEnd('debug');

  return PositionProperty.convertToReferenceFrame(
    time,
    this._value,
    this._referenceFrame,
    referenceFrame,
    result
  );
};

/**
 * Compares this property to the provided property and returns
 * <code>true</code> if they are equal, <code>false</code> otherwise.
 *
 * @param {Property} [other] The other property.
 * @returns {Boolean} <code>true</code> if left and right are equal, <code>false</code> otherwise.
 */
ConstantPositionProperty.prototype.equals = function (other) {
  return (
    this === other ||
    (other instanceof ConstantPositionProperty &&
      Cartesian3.equals(this._value, other._value) &&
      this._referenceFrame === other._referenceFrame)
  );
};
export default ConstantPositionProperty;