text: define([
          '../Core/defaultValue',
          '../Core/defined',
          '../Core/defineProperties',
          '../Core/DeveloperError',
          '../Core/Event',
          './createPropertyDescriptor'
      ], function(
          defaultValue,
          defined,
          defineProperties,
          DeveloperError,
          Event,
          createPropertyDescriptor) {
      'use strict';
  
      /**
       * Describes a graphical point located at the position of the containing {@link Entity}.
       *
       * @alias PointGraphics
       * @constructor
       *
       * @param {Object} [options] Object with the following properties:
       * @param {Property} [options.color=Color.WHITE] A Property specifying the {@link Color} of the point.
       * @param {Property} [options.pixelSize=1] A numeric Property specifying the size in pixels.
       * @param {Property} [options.outlineColor=Color.BLACK] A Property specifying the {@link Color} of the outline.
       * @param {Property} [options.outlineWidth=0] A numeric Property specifying the the outline width in pixels.
       * @param {Property} [options.show=true] A boolean Property specifying the visibility of the point.
       * @param {Property} [options.scaleByDistance] A {@link NearFarScalar} Property used to scale the point based on distance.
       * @param {Property} [options.translucencyByDistance] A {@link NearFarScalar} Property used to set translucency based on distance from the camera.
       * @param {Property} [options.heightReference=HeightReference.NONE] A Property specifying what the height is relative to.
       * @param {Property} [options.distanceDisplayCondition] A Property specifying at what distance from the camera that this point will be displayed.
       */
      function PointGraphics(options) {
          this._color = undefined;
          this._colorSubscription = undefined;
          this._pixelSize = undefined;
          this._pixelSizeSubscription = undefined;
          this._outlineColor = undefined;
          this._outlineColorSubscription = undefined;
          this._outlineWidth = undefined;
          this._outlineWidthSubscription = undefined;
          this._show = undefined;
          this._showSubscription = undefined;
          this._scaleByDistance = undefined;
          this._scaleByDistanceSubscription = undefined;
          this._translucencyByDistance = undefined;
          this._translucencyByDistanceSubscription = undefined;
          this._heightReference = undefined;
          this._heightReferenceSubscription = undefined;
          this._distanceDisplayCondition = undefined;
          this._distanceDisplayConditionSubscription = undefined;
          this._disableDepthTestDistance = undefined;
          this._disableDepthTestDistanceSubscription = undefined;
          this._definitionChanged = new Event();
  
          this.merge(defaultValue(options, defaultValue.EMPTY_OBJECT));
      }
  
      defineProperties(PointGraphics.prototype, {
          /**
           * Gets the event that is raised whenever a property or sub-property is changed or modified.
           * @memberof PointGraphics.prototype
           *
           * @type {Event}
           * @readonly
           */
          definitionChanged : {
              get : function() {
                  return this._definitionChanged;
              }
          },
  
          /**
           * Gets or sets the Property specifying the {@link Color} of the point.
           * @memberof PointGraphics.prototype
           * @type {Property}
           * @default Color.WHITE
           */
          color : createPropertyDescriptor('color'),
  
          /**
           * Gets or sets the numeric Property specifying the size in pixels.
           * @memberof PointGraphics.prototype
           * @type {Property}
           * @default 1
           */
          pixelSize : createPropertyDescriptor('pixelSize'),
  
          /**
           * Gets or sets the Property specifying the {@link Color} of the outline.
           * @memberof PointGraphics.prototype
           * @type {Property}
           * @default Color.BLACK
           */
          outlineColor : createPropertyDescriptor('outlineColor'),
  
          /**
           * Gets or sets the numeric Property specifying the the outline width in pixels.
           * @memberof PointGraphics.prototype
           * @type {Property}
           * @default 0
           */
          outlineWidth : createPropertyDescriptor('outlineWidth'),
  
          /**
           * Gets or sets the boolean Property specifying the visibility of the point.
           * @memberof PointGraphics.prototype
           * @type {Property}
           * @default true
           */
          show : createPropertyDescriptor('show'),
  
          /**
           * Gets or sets the {@link NearFarScalar} Property used to scale the point based on distance.
           * If undefined, a constant size is used.
           * @memberof PointGraphics.prototype
           * @type {Property}
           */
          scaleByDistance : createPropertyDescriptor('scaleByDistance'),
  
          /**
           * Gets or sets {@link NearFarScalar} Property specifying the translucency of the point based on the distance from the camera.
           * A point's translucency will interpolate between the {@link NearFarScalar#nearValue} and
           * {@link NearFarScalar#farValue} while the camera distance falls within the upper and lower bounds
           * of the specified {@link NearFarScalar#near} and {@link NearFarScalar#far}.
           * Outside of these ranges the points's translucency remains clamped to the nearest bound.
           * @memberof PointGraphics.prototype
           * @type {Property}
           */
          translucencyByDistance : createPropertyDescriptor('translucencyByDistance'),
  
          /**
           * Gets or sets the Property specifying the {@link HeightReference}.
           * @memberof PointGraphics.prototype
           * @type {Property}
           * @default HeightReference.NONE
           */
          heightReference : createPropertyDescriptor('heightReference'),
  
          /**
           * Gets or sets the {@link DistanceDisplayCondition} Property specifying at what distance from the camera that this point will be displayed.
           * @memberof PointGraphics.prototype
           * @type {Property}
           */
          distanceDisplayCondition : createPropertyDescriptor('distanceDisplayCondition'),
  
          /**
           * Gets or sets the distance from the camera at which to disable the depth test to, for example, prevent clipping against terrain.
           * When set to zero, the depth test is always applied. When set to Number.POSITIVE_INFINITY, the depth test is never applied.
           * @memberof PointGraphics.prototype
           * @type {Property}
           */
          disableDepthTestDistance : createPropertyDescriptor('disableDepthTestDistance')
      });
  
      /**
       * Duplicates this instance.
       *
       * @param {PointGraphics} [result] The object onto which to store the result.
       * @returns {PointGraphics} The modified result parameter or a new instance if one was not provided.
       */
      PointGraphics.prototype.clone = function(result) {
          if (!defined(result)) {
              return new PointGraphics(this);
          }
          result.color = this.color;
          result.pixelSize = this.pixelSize;
          result.outlineColor = this.outlineColor;
          result.outlineWidth = this.outlineWidth;
          result.show = this.show;
          result.scaleByDistance = this.scaleByDistance;
          result.translucencyByDistance = this._translucencyByDistance;
          result.heightReference = this.heightReference;
          result.distanceDisplayCondition = this.distanceDisplayCondition;
          result.disableDepthTestDistance = this.disableDepthTestDistance;
          return result;
      };
  
      /**
       * Assigns each unassigned property on this object to the value
       * of the same property on the provided source object.
       *
       * @param {PointGraphics} source The object to be merged into this object.
       */
      PointGraphics.prototype.merge = function(source) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(source)) {
              throw new DeveloperError('source is required.');
          }
          //>>includeEnd('debug');
  
          this.color = defaultValue(this.color, source.color);
          this.pixelSize = defaultValue(this.pixelSize, source.pixelSize);
          this.outlineColor = defaultValue(this.outlineColor, source.outlineColor);
          this.outlineWidth = defaultValue(this.outlineWidth, source.outlineWidth);
          this.show = defaultValue(this.show, source.show);
          this.scaleByDistance = defaultValue(this.scaleByDistance, source.scaleByDistance);
          this.translucencyByDistance = defaultValue(this._translucencyByDistance, source.translucencyByDistance);
          this.heightReference = defaultValue(this.heightReference, source.heightReference);
          this.distanceDisplayCondition = defaultValue(this.distanceDisplayCondition, source.distanceDisplayCondition);
          this.disableDepthTestDistance = defaultValue(this.disableDepthTestDistance, source.disableDepthTestDistance);
      };
  
      return PointGraphics;
  });
  