Merge pull request #3908 from AnalyticalGraphicsInc/velocity-vector-property

mramato · mramato · commit 62d63f7d0ab9 · 2016-05-16T12:04:36.000-04:00
Added VelocityVectorProperty
diff --git a/CHANGES.md b/CHANGES.md
@@ -8,6 +8,7 @@ Change Log
 * Deprecated
   *
 * Improved KML NetworkLink compatibility by supporting the `Url` tag. [#3895](https://github.com/AnalyticalGraphicsInc/cesium/pull/3895).
+* Added `VelocityVectorProperty` so billboard's aligned axis can follow the velocity vector.  [#3908](https://github.com/AnalyticalGraphicsInc/cesium/issues/3908)
 * Improve memory management for entity billboard/label/point/path visualization.
 * Fixed exaggerated terrain tiles disappearing. [#3676](https://github.com/AnalyticalGraphicsInc/cesium/issues/3676)
 * Fixed infinite horizontal 2D scrolling in IE/Edge. [#3893](https://github.com/AnalyticalGraphicsInc/cesium/issues/3893)
diff --git a/Source/DataSources/VelocityOrientationProperty.js b/Source/DataSources/VelocityOrientationProperty.js
@@ -11,7 +11,8 @@ define([
         '../Core/Matrix3',
         '../Core/Quaternion',
         '../Core/Transforms',
-        './Property'
+        './Property',
+        './VelocityVectorProperty'
     ], function(
         Cartesian3,
         defaultValue,
@@ -24,7 +25,8 @@ define([
         Matrix3,
         Quaternion,
         Transforms,
-        Property) {
+        Property,
+        VelocityVectorProperty) {
     'use strict';
 
     /**
@@ -47,13 +49,17 @@ define([
      * }));
      */
     function VelocityOrientationProperty(position, ellipsoid) {
-        this._position = undefined;
+        this._velocityVectorProperty = new VelocityVectorProperty(position);
         this._subscription = undefined;
         this._ellipsoid = undefined;
         this._definitionChanged = new Event();
 
-        this.position = position;
         this.ellipsoid = defaultValue(ellipsoid, Ellipsoid.WGS84);
+
+        var that = this;
+        this._velocityVectorProperty.definitionChanged.addEventListener(function() {
+            that._definitionChanged.raiseEvent(that);
+        });
     }
 
     defineProperties(VelocityOrientationProperty.prototype, {
@@ -66,7 +72,7 @@ define([
          */
         isConstant : {
             get : function() {
-                return Property.isConstant(this._position);
+                return Property.isConstant(this._velocityVectorProperty);
             }
         },
         /**
@@ -89,25 +95,10 @@ define([
          */
         position : {
             get : function() {
-                return this._position;
+                return this._velocityVectorProperty.position;
             },
             set : function(value) {
-                var oldValue = this._position;
-                if (oldValue !== value) {
-                    if (defined(oldValue)) {
-                        this._subscription();
-                    }
-
-                    this._position = value;
-
-                    if (defined(value)) {
-                        this._subscription = value._definitionChanged.addEventListener(function() {
-                            this._definitionChanged.raiseEvent(this);
-                        }, this);
-                    }
-
-                    this._definitionChanged.raiseEvent(this);
-                }
+                this._velocityVectorProperty.position = value;
             }
         },
         /**
@@ -130,12 +121,9 @@ define([
         }
     });
 
-    var position1Scratch = new Cartesian3();
-    var position2Scratch = new Cartesian3();
+    var positionScratch = new Cartesian3();
     var velocityScratch = new Cartesian3();
-    var timeScratch = new JulianDate();
     var rotationScratch = new Matrix3();
-    var step = 1.0 / 60.0;
 
     /**
      * Gets the value of the property at the provided time.
@@ -145,43 +133,13 @@ define([
      * @returns {Quaternion} The modified result parameter or a new instance if the result parameter was not supplied.
      */
     VelocityOrientationProperty.prototype.getValue = function(time, result) {
-        //>>includeStart('debug', pragmas.debug);
-        if (!defined(time)) {
-            throw new DeveloperError('time is required');
-        }
-        //>>includeEnd('debug');
-
-        var property = this._position;
-        if (Property.isConstant(property)) {
-            return undefined;
-        }
-
-        var position1 = property.getValue(time, position1Scratch);
-        var position2 = property.getValue(JulianDate.addSeconds(time, step, timeScratch), position2Scratch);
-
-        //If we don't have a position for now, return undefined.
-        if (!defined(position1)) {
-            return undefined;
-        }
+        var velocity = this._velocityVectorProperty._getValue(time, velocityScratch, positionScratch);
 
-        //If we don't have a position for now + step, see if we have a position for now - step.
-        if (!defined(position2)) {
-            position2 = position1;
-            position1 = property.getValue(JulianDate.addSeconds(time, -step, timeScratch), position2Scratch);
-
-            if (!defined(position1)) {
-                return undefined;
-            }
-        }
-
-        if (Cartesian3.equals(position1, position2)) {
+        if (!defined(velocity)) {
             return undefined;
         }
 
-        var velocity = Cartesian3.subtract(position2, position1, velocityScratch);
-        Cartesian3.normalize(velocity, velocity);
-
-        Transforms.rotationMatrixFromPositionVelocity(position1, velocity, this._ellipsoid, rotationScratch);
+        Transforms.rotationMatrixFromPositionVelocity(positionScratch, velocity, this._ellipsoid, rotationScratch);
         return Quaternion.fromRotationMatrix(rotationScratch, result);
     };
 
@@ -195,7 +153,7 @@ define([
     VelocityOrientationProperty.prototype.equals = function(other) {
         return this === other ||//
                (other instanceof VelocityOrientationProperty &&
-                Property.equals(this._position, other._position) &&
+                Property.equals(this._velocityVectorProperty, other._velocityVectorProperty) &&
                 (this._ellipsoid === other._ellipsoid ||
                  this._ellipsoid.equals(other._ellipsoid)));
     };
diff --git a/Source/DataSources/VelocityVectorProperty.js b/Source/DataSources/VelocityVectorProperty.js
@@ -0,0 +1,187 @@
+/*global define*/
+define([
+    '../Core/Cartesian3',
+    '../Core/defaultValue',
+    '../Core/defined',
+    '../Core/defineProperties',
+    '../Core/DeveloperError',
+    '../Core/Event',
+    '../Core/JulianDate',
+    './Property'
+], function(
+    Cartesian3,
+    defaultValue,
+    defined,
+    defineProperties,
+    DeveloperError,
+    Event,
+    JulianDate,
+    Property) {
+    'use strict';
+
+    /**
+     * A {@link Property} which evaluates to a {@link Cartesian3} vector
+     * based on the velocity of the provided {@link PositionProperty}.
+     *
+     * @alias VelocityVectorProperty
+     * @constructor
+     *
+     * @param {Property} [position] The position property used to compute the velocity.
+     *
+     * @example
+     * //Create an entity with a billboard rotated to match its velocity.
+     * var position = new Cesium.SampledProperty();
+     * position.addSamples(...);
+     * var entity = viewer.entities.add({
+     *   position : position,
+     *   billboard : {
+     *     image : 'image.png',
+     *     alignedAxis : new Cesium.VelocityVectorProperty(position)
+     *   }
+     * }));
+     */
+    function VelocityVectorProperty(position) {
+        this._position = undefined;
+        this._subscription = undefined;
+        this._definitionChanged = new Event();
+
+        this.position = position;
+    }
+
+    defineProperties(VelocityVectorProperty.prototype, {
+        /**
+         * Gets a value indicating if this property is constant.
+         * @memberof VelocityVectorProperty.prototype
+         *
+         * @type {Boolean}
+         * @readonly
+         */
+        isConstant : {
+            get : function() {
+                return Property.isConstant(this._position);
+            }
+        },
+        /**
+         * Gets the event that is raised whenever the definition of this property changes.
+         * @memberof VelocityVectorProperty.prototype
+         *
+         * @type {Event}
+         * @readonly
+         */
+        definitionChanged : {
+            get : function() {
+                return this._definitionChanged;
+            }
+        },
+        /**
+         * Gets or sets the position property used to compute orientation.
+         * @memberof VelocityVectorProperty.prototype
+         *
+         * @type {Property}
+         */
+        position : {
+            get : function() {
+                return this._position;
+            },
+            set : function(value) {
+                var oldValue = this._position;
+                if (oldValue !== value) {
+                    if (defined(oldValue)) {
+                        this._subscription();
+                    }
+
+                    this._position = value;
+
+                    if (defined(value)) {
+                        this._subscription = value._definitionChanged.addEventListener(function() {
+                            this._definitionChanged.raiseEvent(this);
+                        }, this);
+                    }
+
+                    this._definitionChanged.raiseEvent(this);
+                }
+            }
+        }
+    });
+
+    var position1Scratch = new Cartesian3();
+    var position2Scratch = new Cartesian3();
+    var velocityScratch = new Cartesian3();
+    var timeScratch = new JulianDate();
+    var step = 1.0 / 60.0;
+
+    /**
+     * Gets the value of the property at the provided time.
+     *
+     * @param {JulianDate} [time] The time for which to retrieve the value.
+     * @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.
+     */
+    VelocityVectorProperty.prototype.getValue = function(time, result) {
+        return this._getValue(time, result);
+    };
+
+    /**
+     * @private
+     */
+    VelocityVectorProperty.prototype._getValue = function(time, velocityResult, positionResult) {
+        //>>includeStart('debug', pragmas.debug);
+        if (!defined(time)) {
+            throw new DeveloperError('time is required');
+        }
+        //>>includeEnd('debug');
+
+        if (!defined(velocityResult)) {
+            velocityResult = new Cartesian3();
+        }
+
+        var property = this._position;
+        if (Property.isConstant(property)) {
+            return undefined;
+        }
+
+        var position1 = property.getValue(time, position1Scratch);
+        var position2 = property.getValue(JulianDate.addSeconds(time, step, timeScratch), position2Scratch);
+
+        //If we don't have a position for now, return undefined.
+        if (!defined(position1)) {
+            return undefined;
+        }
+
+        //If we don't have a position for now + step, see if we have a position for now - step.
+        if (!defined(position2)) {
+            position2 = position1;
+            position1 = property.getValue(JulianDate.addSeconds(time, -step, timeScratch), position2Scratch);
+
+            if (!defined(position1)) {
+                return undefined;
+            }
+        }
+
+        if (Cartesian3.equals(position1, position2)) {
+            return undefined;
+        }
+
+        if (defined(positionResult)) {
+            position1.clone(positionResult);
+        }
+
+        var velocity = Cartesian3.subtract(position2, position1, velocityScratch);
+        return Cartesian3.normalize(velocity, velocityResult);
+    };
+
+    /**
+     * 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.
+     */
+    VelocityVectorProperty.prototype.equals = function(other) {
+        return this === other ||//
+               (other instanceof VelocityVectorProperty &&
+                Property.equals(this._position, other._position));
+    };
+
+    return VelocityVectorProperty;
+});
diff --git a/Specs/DataSources/VelocityOrientationPropertySpec.js b/Specs/DataSources/VelocityOrientationPropertySpec.js
@@ -31,7 +31,7 @@ defineSuite([
         expect(property.definitionChanged).toBeInstanceOf(Event);
         expect(property.position).toBeUndefined();
         expect(property.ellipsoid).toBe(Ellipsoid.WGS84);
-        expect(property.getValue(time)).toBe(undefined);
+        expect(property.getValue(time)).toBeUndefined();
     });
 
     it('can construct with arguments', function() {
@@ -41,7 +41,7 @@ defineSuite([
         expect(property.definitionChanged).toBeInstanceOf(Event);
         expect(property.position).toBe(position);
         expect(property.ellipsoid).toBe(Ellipsoid.UNIT_SPHERE);
-        expect(property.getValue(time)).toBe(undefined);
+        expect(property.getValue(time)).toBeUndefined();
     });
 
     it('setting position raises definitionChanged event', function() {
diff --git a/Specs/DataSources/VelocityVectorPropertySpec.js b/Specs/DataSources/VelocityVectorPropertySpec.js

Original file line number	Diff line number	Diff line change
`@@ -8,6 +8,7 @@ Change Log`
`8`	`8`	`* Deprecated`
`9`	`9`	`*`
`10`	`10`	* Improved KML NetworkLink compatibility by supporting the `Url` tag. [#3895](https://github.com/AnalyticalGraphicsInc/cesium/pull/3895).
	`11`	+* Added `VelocityVectorProperty` so billboard's aligned axis can follow the velocity vector. [#3908](https://github.com/AnalyticalGraphicsInc/cesium/issues/3908)
`11`	`12`	`* Improve memory management for entity billboard/label/point/path visualization.`
`12`	`13`	`* Fixed exaggerated terrain tiles disappearing. [#3676](https://github.com/AnalyticalGraphicsInc/cesium/issues/3676)`
`13`	`14`	`* Fixed infinite horizontal 2D scrolling in IE/Edge. [#3893](https://github.com/AnalyticalGraphicsInc/cesium/issues/3893)`