-
Notifications
You must be signed in to change notification settings - Fork 3.5k
/
VelocityOrientationProperty.js
204 lines (186 loc) · 6.79 KB
/
VelocityOrientationProperty.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
/*global define*/
define([
'../Core/Cartesian3',
'../Core/defaultValue',
'../Core/defined',
'../Core/defineProperties',
'../Core/DeveloperError',
'../Core/Ellipsoid',
'../Core/Event',
'../Core/JulianDate',
'../Core/Matrix3',
'../Core/Quaternion',
'../Core/Transforms',
'./Property'
], function(
Cartesian3,
defaultValue,
defined,
defineProperties,
DeveloperError,
Ellipsoid,
Event,
JulianDate,
Matrix3,
Quaternion,
Transforms,
Property) {
"use strict";
/**
* A {@link Property} which evaluates to a {@link Quaternion} rotation
* based on the velocity of the provided {@link PositionProperty}.
*
* @alias VelocityOrientationProperty
* @constructor
*
* @param {Property} [position] The position property used to compute the orientation.
* @param {Ellipsoid} [ellipsoid=Ellipsoid.WGS84] The ellipsoid used to determine which way is up.
*
* @example
* //Create an entity with position and orientation.
* var position = new Cesium.SampledProperty();
* position.addSamples(...);
* var entity = viewer.entities.add({
* position : position,
* orientation : new Cesium.VelocityOrientationProperty(position)
* }));
*/
var VelocityOrientationProperty = function(position, ellipsoid) {
this._position = undefined;
this._subscription = undefined;
this._ellipsoid = undefined;
this._definitionChanged = new Event();
this.position = position;
this.ellipsoid = defaultValue(ellipsoid, Ellipsoid.WGS84);
};
defineProperties(VelocityOrientationProperty.prototype, {
/**
* Gets a value indicating if this property is constant.
* @memberof VelocityOrientationProperty.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 VelocityOrientationProperty.prototype
*
* @type {Event}
* @readonly
*/
definitionChanged : {
get : function() {
return this._definitionChanged;
}
},
/**
* Gets or sets the position property used to compute orientation.
* @memberof VelocityOrientationProperty.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);
}
}
},
/**
* Gets or sets the ellipsoid used to determine which way is up.
* @memberof VelocityOrientationProperty.prototype
*
* @type {Property}
*/
ellipsoid : {
get : function() {
return this._ellipsoid;
},
set : function(value) {
var oldValue = this._ellipsoid;
if (oldValue !== value) {
this._ellipsoid = value;
this._definitionChanged.raiseEvent(this);
}
}
}
});
var position1Scratch = new Cartesian3();
var position2Scratch = 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.
*
* @param {JulianDate} [time] The time for which to retrieve the value.
* @param {Quaternion} [result] The object to store the value into, if omitted, a new instance is created and returned.
* @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;
}
//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;
}
var velocity = Cartesian3.subtract(position2, position1, velocityScratch);
Cartesian3.normalize(velocity, velocity);
var rotation = Transforms.rotationMatrixFromPositionVelocity(position1, velocity, this._ellipsoid, rotationScratch);
return Quaternion.fromRotationMatrix(rotationScratch, 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.
*/
VelocityOrientationProperty.prototype.equals = function(other) {
return this === other ||//
(other instanceof VelocityOrientationProperty &&
Property.equals(this._position, other._position) &&
(this._ellipsoid === other._ellipsoid ||
this._ellipsoid.equals(other._ellipsoid)));
};
return VelocityOrientationProperty;
});