text: /*global define*/
  define([
          './defaultValue',
          './defined',
          './DeveloperError',
          './freezeObject',
          './Math'
      ], function(
          defaultValue,
          defined,
          DeveloperError,
          freezeObject,
          CesiumMath) {
      'use strict';
  
      /**
       * A 4D Cartesian point.
       * @alias Cartesian4
       * @constructor
       *
       * @param {Number} [x=0.0] The X component.
       * @param {Number} [y=0.0] The Y component.
       * @param {Number} [z=0.0] The Z component.
       * @param {Number} [w=0.0] The W component.
       *
       * @see Cartesian2
       * @see Cartesian3
       * @see Packable
       */
      function Cartesian4(x, y, z, w) {
          /**
           * The X component.
           * @type {Number}
           * @default 0.0
           */
          this.x = defaultValue(x, 0.0);
  
          /**
           * The Y component.
           * @type {Number}
           * @default 0.0
           */
          this.y = defaultValue(y, 0.0);
  
          /**
           * The Z component.
           * @type {Number}
           * @default 0.0
           */
          this.z = defaultValue(z, 0.0);
  
          /**
           * The W component.
           * @type {Number}
           * @default 0.0
           */
          this.w = defaultValue(w, 0.0);
      }
  
      /**
       * Creates a Cartesian4 instance from x, y, z and w coordinates.
       *
       * @param {Number} x The x coordinate.
       * @param {Number} y The y coordinate.
       * @param {Number} z The z coordinate.
       * @param {Number} w The w coordinate.
       * @param {Cartesian4} [result] The object onto which to store the result.
       * @returns {Cartesian4} The modified result parameter or a new Cartesian4 instance if one was not provided.
       */
      Cartesian4.fromElements = function(x, y, z, w, result) {
          if (!defined(result)) {
              return new Cartesian4(x, y, z, w);
          }
  
          result.x = x;
          result.y = y;
          result.z = z;
          result.w = w;
          return result;
      };
  
      /**
       * Creates a Cartesian4 instance from a {@link Color}. <code>red</code>, <code>green</code>, <code>blue</code>,
       * and <code>alpha</code> map to <code>x</code>, <code>y</code>, <code>z</code>, and <code>w</code>, respectively.
       *
       * @param {Color} color The source color.
       * @param {Cartesian4} [result] The object onto which to store the result.
       * @returns {Cartesian4} The modified result parameter or a new Cartesian4 instance if one was not provided.
       */
      Cartesian4.fromColor = function(color, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(color)) {
              throw new DeveloperError('color is required');
          }
          //>>includeEnd('debug');
          if (!defined(result)) {
              return new Cartesian4(color.red, color.green, color.blue, color.alpha);
          }
  
          result.x = color.red;
          result.y = color.green;
          result.z = color.blue;
          result.w = color.alpha;
          return result;
      };
  
      /**
       * Duplicates a Cartesian4 instance.
       *
       * @param {Cartesian4} cartesian The Cartesian to duplicate.
       * @param {Cartesian4} [result] The object onto which to store the result.
       * @returns {Cartesian4} The modified result parameter or a new Cartesian4 instance if one was not provided. (Returns undefined if cartesian is undefined)
       */
      Cartesian4.clone = function(cartesian, result) {
          if (!defined(cartesian)) {
              return undefined;
          }
  
          if (!defined(result)) {
              return new Cartesian4(cartesian.x, cartesian.y, cartesian.z, cartesian.w);
          }
  
          result.x = cartesian.x;
          result.y = cartesian.y;
          result.z = cartesian.z;
          result.w = cartesian.w;
          return result;
      };
  
  
      /**
       * The number of elements used to pack the object into an array.
       * @type {Number}
       */
      Cartesian4.packedLength = 4;
  
      /**
       * Stores the provided instance into the provided array.
       *
       * @param {Cartesian4} value The value to pack.
       * @param {Number[]} array The array to pack into.
       * @param {Number} [startingIndex=0] The index into the array at which to start packing the elements.
       *
       * @returns {Number[]} The array that was packed into
       */
      Cartesian4.pack = function(value, array, startingIndex) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(value)) {
              throw new DeveloperError('value is required');
          }
          if (!defined(array)) {
              throw new DeveloperError('array is required');
          }
          //>>includeEnd('debug');
  
          startingIndex = defaultValue(startingIndex, 0);
  
          array[startingIndex++] = value.x;
          array[startingIndex++] = value.y;
          array[startingIndex++] = value.z;
          array[startingIndex] = value.w;
  
          return array;
      };
  
      /**
       * Retrieves an instance from a packed array.
       *
       * @param {Number[]} array The packed array.
       * @param {Number} [startingIndex=0] The starting index of the element to be unpacked.
       * @param {Cartesian4} [result] The object into which to store the result.
       * @returns {Cartesian4}  The modified result parameter or a new Cartesian4 instance if one was not provided.
       */
      Cartesian4.unpack = function(array, startingIndex, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(array)) {
              throw new DeveloperError('array is required');
          }
          //>>includeEnd('debug');
  
          startingIndex = defaultValue(startingIndex, 0);
  
          if (!defined(result)) {
              result = new Cartesian4();
          }
          result.x = array[startingIndex++];
          result.y = array[startingIndex++];
          result.z = array[startingIndex++];
          result.w = array[startingIndex];
          return result;
      };
  
      /**
       * Flattens an array of Cartesian4s into and array of components.
       *
       * @param {Cartesian4[]} array The array of cartesians to pack.
       * @param {Number[]} result The array onto which to store the result.
       * @returns {Number[]} The packed array.
       */
      Cartesian4.packArray = function(array, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(array)) {
              throw new DeveloperError('array is required');
          }
          //>>includeEnd('debug');
  
          var length = array.length;
          if (!defined(result)) {
              result = new Array(length * 4);
          } else {
              result.length = length * 4;
          }
  
          for (var i = 0; i < length; ++i) {
              Cartesian4.pack(array[i], result, i * 4);
          }
          return result;
      };
  
      /**
       * Unpacks an array of cartesian components into and array of Cartesian4s.
       *
       * @param {Number[]} array The array of components to unpack.
       * @param {Cartesian4[]} result The array onto which to store the result.
       * @returns {Cartesian4[]} The unpacked array.
       */
      Cartesian4.unpackArray = function(array, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(array)) {
              throw new DeveloperError('array is required');
          }
          //>>includeEnd('debug');
  
          var length = array.length;
          if (!defined(result)) {
              result = new Array(length / 4);
          } else {
              result.length = length / 4;
          }
  
          for (var i = 0; i < length; i += 4) {
              var index = i / 4;
              result[index] = Cartesian4.unpack(array, i, result[index]);
          }
          return result;
      };
  
      /**
       * Creates a Cartesian4 from four consecutive elements in an array.
       * @function
       *
       * @param {Number[]} array The array whose four consecutive elements correspond to the x, y, z, and w components, respectively.
       * @param {Number} [startingIndex=0] The offset into the array of the first element, which corresponds to the x component.
       * @param {Cartesian4} [result] The object onto which to store the result.
       * @returns {Cartesian4}  The modified result parameter or a new Cartesian4 instance if one was not provided.
       *
       * @example
       * // Create a Cartesian4 with (1.0, 2.0, 3.0, 4.0)
       * var v = [1.0, 2.0, 3.0, 4.0];
       * var p = Cesium.Cartesian4.fromArray(v);
       *
       * // Create a Cartesian4 with (1.0, 2.0, 3.0, 4.0) using an offset into an array
       * var v2 = [0.0, 0.0, 1.0, 2.0, 3.0, 4.0];
       * var p2 = Cesium.Cartesian4.fromArray(v2, 2);
       */
      Cartesian4.fromArray = Cartesian4.unpack;
  
      /**
       * Computes the value of the maximum component for the supplied Cartesian.
       *
       * @param {Cartesian4} cartesian The cartesian to use.
       * @returns {Number} The value of the maximum component.
       */
      Cartesian4.maximumComponent = function(cartesian) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(cartesian)) {
              throw new DeveloperError('cartesian is required');
          }
          //>>includeEnd('debug');
  
          return Math.max(cartesian.x, cartesian.y, cartesian.z, cartesian.w);
      };
  
      /**
       * Computes the value of the minimum component for the supplied Cartesian.
       *
       * @param {Cartesian4} cartesian The cartesian to use.
       * @returns {Number} The value of the minimum component.
       */
      Cartesian4.minimumComponent = function(cartesian) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(cartesian)) {
              throw new DeveloperError('cartesian is required');
          }
          //>>includeEnd('debug');
  
          return Math.min(cartesian.x, cartesian.y, cartesian.z, cartesian.w);
      };
  
      /**
       * Compares two Cartesians and computes a Cartesian which contains the minimum components of the supplied Cartesians.
       *
       * @param {Cartesian4} first A cartesian to compare.
       * @param {Cartesian4} second A cartesian to compare.
       * @param {Cartesian4} result The object into which to store the result.
       * @returns {Cartesian4} A cartesian with the minimum components.
       */
      Cartesian4.minimumByComponent = function(first, second, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(first)) {
              throw new DeveloperError('first is required.');
          }
          if (!defined(second)) {
              throw new DeveloperError('second is required.');
          }
          if (!defined(result)) {
              throw new DeveloperError('result is required.');
          }
          //>>includeEnd('debug');
  
          result.x = Math.min(first.x, second.x);
          result.y = Math.min(first.y, second.y);
          result.z = Math.min(first.z, second.z);
          result.w = Math.min(first.w, second.w);
  
          return result;
      };
  
      /**
       * Compares two Cartesians and computes a Cartesian which contains the maximum components of the supplied Cartesians.
       *
       * @param {Cartesian4} first A cartesian to compare.
       * @param {Cartesian4} second A cartesian to compare.
       * @param {Cartesian4} result The object into which to store the result.
       * @returns {Cartesian4} A cartesian with the maximum components.
       */
      Cartesian4.maximumByComponent = function(first, second, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(first)) {
              throw new DeveloperError('first is required.');
          }
          if (!defined(second)) {
              throw new DeveloperError('second is required.');
          }
          if (!defined(result)) {
              throw new DeveloperError('result is required.');
          }
          //>>includeEnd('debug');
  
          result.x = Math.max(first.x, second.x);
          result.y = Math.max(first.y, second.y);
          result.z = Math.max(first.z, second.z);
          result.w = Math.max(first.w, second.w);
  
          return result;
      };
  
      /**
       * Computes the provided Cartesian's squared magnitude.
       *
       * @param {Cartesian4} cartesian The Cartesian instance whose squared magnitude is to be computed.
       * @returns {Number} The squared magnitude.
       */
      Cartesian4.magnitudeSquared = function(cartesian) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(cartesian)) {
              throw new DeveloperError('cartesian is required');
          }
          //>>includeEnd('debug');
  
          return cartesian.x * cartesian.x + cartesian.y * cartesian.y + cartesian.z * cartesian.z + cartesian.w * cartesian.w;
      };
  
      /**
       * Computes the Cartesian's magnitude (length).
       *
       * @param {Cartesian4} cartesian The Cartesian instance whose magnitude is to be computed.
       * @returns {Number} The magnitude.
       */
      Cartesian4.magnitude = function(cartesian) {
          return Math.sqrt(Cartesian4.magnitudeSquared(cartesian));
      };
  
      var distanceScratch = new Cartesian4();
  
      /**
       * Computes the 4-space distance between two points.
       *
       * @param {Cartesian4} left The first point to compute the distance from.
       * @param {Cartesian4} right The second point to compute the distance to.
       * @returns {Number} The distance between two points.
       *
       * @example
       * // Returns 1.0
       * var d = Cesium.Cartesian4.distance(
       *   new Cesium.Cartesian4(1.0, 0.0, 0.0, 0.0),
       *   new Cesium.Cartesian4(2.0, 0.0, 0.0, 0.0));
       */
      Cartesian4.distance = function(left, right) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(left) || !defined(right)) {
              throw new DeveloperError('left and right are required.');
          }
          //>>includeEnd('debug');
  
          Cartesian4.subtract(left, right, distanceScratch);
          return Cartesian4.magnitude(distanceScratch);
      };
  
      /**
       * Computes the squared distance between two points.  Comparing squared distances
       * using this function is more efficient than comparing distances using {@link Cartesian4#distance}.
       *
       * @param {Cartesian4} left The first point to compute the distance from.
       * @param {Cartesian4} right The second point to compute the distance to.
       * @returns {Number} The distance between two points.
       *
       * @example
       * // Returns 4.0, not 2.0
       * var d = Cesium.Cartesian4.distance(
       *   new Cesium.Cartesian4(1.0, 0.0, 0.0, 0.0),
       *   new Cesium.Cartesian4(3.0, 0.0, 0.0, 0.0));
       */
      Cartesian4.distanceSquared = function(left, right) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(left) || !defined(right)) {
              throw new DeveloperError('left and right are required.');
          }
          //>>includeEnd('debug');
  
          Cartesian4.subtract(left, right, distanceScratch);
          return Cartesian4.magnitudeSquared(distanceScratch);
      };
  
      /**
       * Computes the normalized form of the supplied Cartesian.
       *
       * @param {Cartesian4} cartesian The Cartesian to be normalized.
       * @param {Cartesian4} result The object onto which to store the result.
       * @returns {Cartesian4} The modified result parameter.
       */
      Cartesian4.normalize = function(cartesian, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(cartesian)) {
              throw new DeveloperError('cartesian is required');
          }
          if (!defined(result)) {
              throw new DeveloperError('result is required');
          }
          //>>includeEnd('debug');
  
          var magnitude = Cartesian4.magnitude(cartesian);
  
          result.x = cartesian.x / magnitude;
          result.y = cartesian.y / magnitude;
          result.z = cartesian.z / magnitude;
          result.w = cartesian.w / magnitude;
  
          //>>includeStart('debug', pragmas.debug);
          if (isNaN(result.x) || isNaN(result.y) || isNaN(result.z) || isNaN(result.w)) {
              throw new DeveloperError('normalized result is not a number');
          }
          //>>includeEnd('debug');
  
          return result;
      };
  
      /**
       * Computes the dot (scalar) product of two Cartesians.
       *
       * @param {Cartesian4} left The first Cartesian.
       * @param {Cartesian4} right The second Cartesian.
       * @returns {Number} The dot product.
       */
      Cartesian4.dot = function(left, right) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(left)) {
              throw new DeveloperError('left is required');
          }
          if (!defined(right)) {
              throw new DeveloperError('right is required');
          }
          //>>includeEnd('debug');
  
          return left.x * right.x + left.y * right.y + left.z * right.z + left.w * right.w;
      };
  
      /**
       * Computes the componentwise product of two Cartesians.
       *
       * @param {Cartesian4} left The first Cartesian.
       * @param {Cartesian4} right The second Cartesian.
       * @param {Cartesian4} result The object onto which to store the result.
       * @returns {Cartesian4} The modified result parameter.
       */
      Cartesian4.multiplyComponents = function(left, right, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(left)) {
              throw new DeveloperError('left is required');
          }
          if (!defined(right)) {
              throw new DeveloperError('right is required');
          }
          if (!defined(result)) {
              throw new DeveloperError('result is required');
          }
          //>>includeEnd('debug');
  
          result.x = left.x * right.x;
          result.y = left.y * right.y;
          result.z = left.z * right.z;
          result.w = left.w * right.w;
          return result;
      };
  
      /**
       * Computes the componentwise quotient of two Cartesians.
       *
       * @param {Cartesian4} left The first Cartesian.
       * @param {Cartesian4} right The second Cartesian.
       * @param {Cartesian4} result The object onto which to store the result.
       * @returns {Cartesian4} The modified result parameter.
       */
      Cartesian4.divideComponents = function(left, right, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(left)) {
              throw new DeveloperError('left is required');
          }
          if (!defined(right)) {
              throw new DeveloperError('right is required');
          }
          if (!defined(result)) {
              throw new DeveloperError('result is required');
          }
          //>>includeEnd('debug');
  
          result.x = left.x / right.x;
          result.y = left.y / right.y;
          result.z = left.z / right.z;
          result.w = left.w / right.w;
          return result;
      };
  
      /**
       * Computes the componentwise sum of two Cartesians.
       *
       * @param {Cartesian4} left The first Cartesian.
       * @param {Cartesian4} right The second Cartesian.
       * @param {Cartesian4} result The object onto which to store the result.
       * @returns {Cartesian4} The modified result parameter.
       */
      Cartesian4.add = function(left, right, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(left)) {
              throw new DeveloperError('left is required');
          }
          if (!defined(right)) {
              throw new DeveloperError('right is required');
          }
          if (!defined(result)) {
              throw new DeveloperError('result is required');
          }
          //>>includeEnd('debug');
  
          result.x = left.x + right.x;
          result.y = left.y + right.y;
          result.z = left.z + right.z;
          result.w = left.w + right.w;
          return result;
      };
  
      /**
       * Computes the componentwise difference of two Cartesians.
       *
       * @param {Cartesian4} left The first Cartesian.
       * @param {Cartesian4} right The second Cartesian.
       * @param {Cartesian4} result The object onto which to store the result.
       * @returns {Cartesian4} The modified result parameter.
       */
      Cartesian4.subtract = function(left, right, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(left)) {
              throw new DeveloperError('left is required');
          }
          if (!defined(right)) {
              throw new DeveloperError('right is required');
          }
          if (!defined(result)) {
              throw new DeveloperError('result is required');
          }
          //>>includeEnd('debug');
  
          result.x = left.x - right.x;
          result.y = left.y - right.y;
          result.z = left.z - right.z;
          result.w = left.w - right.w;
          return result;
      };
  
      /**
       * Multiplies the provided Cartesian componentwise by the provided scalar.
       *
       * @param {Cartesian4} cartesian The Cartesian to be scaled.
       * @param {Number} scalar The scalar to multiply with.
       * @param {Cartesian4} result The object onto which to store the result.
       * @returns {Cartesian4} The modified result parameter.
       */
      Cartesian4.multiplyByScalar = function(cartesian, scalar, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(cartesian)) {
              throw new DeveloperError('cartesian is required');
          }
          if (typeof scalar !== 'number') {
              throw new DeveloperError('scalar is required and must be a number.');
          }
          if (!defined(result)) {
              throw new DeveloperError('result is required');
          }
          //>>includeEnd('debug');
  
          result.x = cartesian.x * scalar;
          result.y = cartesian.y * scalar;
          result.z = cartesian.z * scalar;
          result.w = cartesian.w * scalar;
          return result;
      };
  
      /**
       * Divides the provided Cartesian componentwise by the provided scalar.
       *
       * @param {Cartesian4} cartesian The Cartesian to be divided.
       * @param {Number} scalar The scalar to divide by.
       * @param {Cartesian4} result The object onto which to store the result.
       * @returns {Cartesian4} The modified result parameter.
       */
      Cartesian4.divideByScalar = function(cartesian, scalar, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(cartesian)) {
              throw new DeveloperError('cartesian is required');
          }
          if (typeof scalar !== 'number') {
              throw new DeveloperError('scalar is required and must be a number.');
          }
          if (!defined(result)) {
              throw new DeveloperError('result is required');
          }
          //>>includeEnd('debug');
  
          result.x = cartesian.x / scalar;
          result.y = cartesian.y / scalar;
          result.z = cartesian.z / scalar;
          result.w = cartesian.w / scalar;
          return result;
      };
  
      /**
       * Negates the provided Cartesian.
       *
       * @param {Cartesian4} cartesian The Cartesian to be negated.
       * @param {Cartesian4} result The object onto which to store the result.
       * @returns {Cartesian4} The modified result parameter.
       */
      Cartesian4.negate = function(cartesian, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(cartesian)) {
              throw new DeveloperError('cartesian is required');
          }
          if (!defined(result)) {
              throw new DeveloperError('result is required');
          }
          //>>includeEnd('debug');
  
          result.x = -cartesian.x;
          result.y = -cartesian.y;
          result.z = -cartesian.z;
          result.w = -cartesian.w;
          return result;
      };
  
      /**
       * Computes the absolute value of the provided Cartesian.
       *
       * @param {Cartesian4} cartesian The Cartesian whose absolute value is to be computed.
       * @param {Cartesian4} result The object onto which to store the result.
       * @returns {Cartesian4} The modified result parameter.
       */
      Cartesian4.abs = function(cartesian, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(cartesian)) {
              throw new DeveloperError('cartesian is required');
          }
          if (!defined(result)) {
              throw new DeveloperError('result is required');
          }
          //>>includeEnd('debug');
  
          result.x = Math.abs(cartesian.x);
          result.y = Math.abs(cartesian.y);
          result.z = Math.abs(cartesian.z);
          result.w = Math.abs(cartesian.w);
          return result;
      };
  
      var lerpScratch = new Cartesian4();
      /**
       * Computes the linear interpolation or extrapolation at t using the provided cartesians.
       *
       * @param {Cartesian4} start The value corresponding to t at 0.0.
       * @param {Cartesian4}end The value corresponding to t at 1.0.
       * @param {Number} t The point along t at which to interpolate.
       * @param {Cartesian4} result The object onto which to store the result.
       * @returns {Cartesian4} The modified result parameter.
       */
      Cartesian4.lerp = function(start, end, t, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(start)) {
              throw new DeveloperError('start is required.');
          }
          if (!defined(end)) {
              throw new DeveloperError('end is required.');
          }
          if (typeof t !== 'number') {
              throw new DeveloperError('t is required and must be a number.');
          }
          if (!defined(result)) {
              throw new DeveloperError('result is required.');
          }
          //>>includeEnd('debug');
  
          Cartesian4.multiplyByScalar(end, t, lerpScratch);
          result = Cartesian4.multiplyByScalar(start, 1.0 - t, result);
          return Cartesian4.add(lerpScratch, result, result);
      };
  
      var mostOrthogonalAxisScratch = new Cartesian4();
      /**
       * Returns the axis that is most orthogonal to the provided Cartesian.
       *
       * @param {Cartesian4} cartesian The Cartesian on which to find the most orthogonal axis.
       * @param {Cartesian4} result The object onto which to store the result.
       * @returns {Cartesian4} The most orthogonal axis.
       */
      Cartesian4.mostOrthogonalAxis = function(cartesian, result) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(cartesian)) {
              throw new DeveloperError('cartesian is required.');
          }
          if (!defined(result)) {
              throw new DeveloperError('result is required.');
          }
          //>>includeEnd('debug');
  
          var f = Cartesian4.normalize(cartesian, mostOrthogonalAxisScratch);
          Cartesian4.abs(f, f);
  
          if (f.x <= f.y) {
              if (f.x <= f.z) {
                  if (f.x <= f.w) {
                      result = Cartesian4.clone(Cartesian4.UNIT_X, result);
                  } else {
                      result = Cartesian4.clone(Cartesian4.UNIT_W, result);
                  }
              } else if (f.z <= f.w) {
                  result = Cartesian4.clone(Cartesian4.UNIT_Z, result);
              } else {
                  result = Cartesian4.clone(Cartesian4.UNIT_W, result);
              }
          } else if (f.y <= f.z) {
              if (f.y <= f.w) {
                  result = Cartesian4.clone(Cartesian4.UNIT_Y, result);
              } else {
                  result = Cartesian4.clone(Cartesian4.UNIT_W, result);
              }
          } else if (f.z <= f.w) {
              result = Cartesian4.clone(Cartesian4.UNIT_Z, result);
          } else {
              result = Cartesian4.clone(Cartesian4.UNIT_W, result);
          }
  
          return result;
      };
  
      /**
       * Compares the provided Cartesians componentwise and returns
       * <code>true</code> if they are equal, <code>false</code> otherwise.
       *
       * @param {Cartesian4} [left] The first Cartesian.
       * @param {Cartesian4} [right] The second Cartesian.
       * @returns {Boolean} <code>true</code> if left and right are equal, <code>false</code> otherwise.
       */
      Cartesian4.equals = function(left, right) {
          return (left === right) ||
                 ((defined(left)) &&
                  (defined(right)) &&
                  (left.x === right.x) &&
                  (left.y === right.y) &&
                  (left.z === right.z) &&
                  (left.w === right.w));
      };
  
      /**
       * @private
       */
      Cartesian4.equalsArray = function(cartesian, array, offset) {
          return cartesian.x === array[offset] &&
                 cartesian.y === array[offset + 1] &&
                 cartesian.z === array[offset + 2] &&
                 cartesian.w === array[offset + 3];
      };
  
      /**
       * Compares the provided Cartesians componentwise and returns
       * <code>true</code> if they pass an absolute or relative tolerance test,
       * <code>false</code> otherwise.
       *
       * @param {Cartesian4} [left] The first Cartesian.
       * @param {Cartesian4} [right] The second Cartesian.
       * @param {Number} relativeEpsilon The relative epsilon tolerance to use for equality testing.
       * @param {Number} [absoluteEpsilon=relativeEpsilon] The absolute epsilon tolerance to use for equality testing.
       * @returns {Boolean} <code>true</code> if left and right are within the provided epsilon, <code>false</code> otherwise.
       */
      Cartesian4.equalsEpsilon = function(left, right, relativeEpsilon, absoluteEpsilon) {
          return (left === right) ||
                 (defined(left) &&
                  defined(right) &&
                  CesiumMath.equalsEpsilon(left.x, right.x, relativeEpsilon, absoluteEpsilon) &&
                  CesiumMath.equalsEpsilon(left.y, right.y, relativeEpsilon, absoluteEpsilon) &&
                  CesiumMath.equalsEpsilon(left.z, right.z, relativeEpsilon, absoluteEpsilon) &&
                  CesiumMath.equalsEpsilon(left.w, right.w, relativeEpsilon, absoluteEpsilon));
      };
  
      /**
       * An immutable Cartesian4 instance initialized to (0.0, 0.0, 0.0, 0.0).
       *
       * @type {Cartesian4}
       * @constant
       */
      Cartesian4.ZERO = freezeObject(new Cartesian4(0.0, 0.0, 0.0, 0.0));
  
      /**
       * An immutable Cartesian4 instance initialized to (1.0, 0.0, 0.0, 0.0).
       *
       * @type {Cartesian4}
       * @constant
       */
      Cartesian4.UNIT_X = freezeObject(new Cartesian4(1.0, 0.0, 0.0, 0.0));
  
      /**
       * An immutable Cartesian4 instance initialized to (0.0, 1.0, 0.0, 0.0).
       *
       * @type {Cartesian4}
       * @constant
       */
      Cartesian4.UNIT_Y = freezeObject(new Cartesian4(0.0, 1.0, 0.0, 0.0));
  
      /**
       * An immutable Cartesian4 instance initialized to (0.0, 0.0, 1.0, 0.0).
       *
       * @type {Cartesian4}
       * @constant
       */
      Cartesian4.UNIT_Z = freezeObject(new Cartesian4(0.0, 0.0, 1.0, 0.0));
  
      /**
       * An immutable Cartesian4 instance initialized to (0.0, 0.0, 0.0, 1.0).
       *
       * @type {Cartesian4}
       * @constant
       */
      Cartesian4.UNIT_W = freezeObject(new Cartesian4(0.0, 0.0, 0.0, 1.0));
  
      /**
       * Duplicates this Cartesian4 instance.
       *
       * @param {Cartesian4} [result] The object onto which to store the result.
       * @returns {Cartesian4} The modified result parameter or a new Cartesian4 instance if one was not provided.
       */
      Cartesian4.prototype.clone = function(result) {
          return Cartesian4.clone(this, result);
      };
  
      /**
       * Compares this Cartesian against the provided Cartesian componentwise and returns
       * <code>true</code> if they are equal, <code>false</code> otherwise.
       *
       * @param {Cartesian4} [right] The right hand side Cartesian.
       * @returns {Boolean} <code>true</code> if they are equal, <code>false</code> otherwise.
       */
      Cartesian4.prototype.equals = function(right) {
          return Cartesian4.equals(this, right);
      };
  
      /**
       * Compares this Cartesian against the provided Cartesian componentwise and returns
       * <code>true</code> if they pass an absolute or relative tolerance test,
       * <code>false</code> otherwise.
       *
       * @param {Cartesian4} [right] The right hand side Cartesian.
       * @param {Number} relativeEpsilon The relative epsilon tolerance to use for equality testing.
       * @param {Number} [absoluteEpsilon=relativeEpsilon] The absolute epsilon tolerance to use for equality testing.
       * @returns {Boolean} <code>true</code> if they are within the provided epsilon, <code>false</code> otherwise.
       */
      Cartesian4.prototype.equalsEpsilon = function(right, relativeEpsilon, absoluteEpsilon) {
          return Cartesian4.equalsEpsilon(this, right, relativeEpsilon, absoluteEpsilon);
      };
  
      /**
       * Creates a string representing this Cartesian in the format '(x, y)'.
       *
       * @returns {String} A string representing the provided Cartesian in the format '(x, y)'.
       */
      Cartesian4.prototype.toString = function() {
          return '(' + this.x + ', ' + this.y + ', ' + this.z + ', ' + this.w + ')';
      };
  
      return Cartesian4;
  });
  