/
SphereEmitter.js
74 lines (66 loc) · 2.25 KB
/
SphereEmitter.js
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define([
'../Core/Cartesian3',
'../Core/Check',
'../Core/defaultValue',
'../Core/defineProperties',
'../Core/Math'
], function(
Cartesian3,
Check,
defaultValue,
defineProperties,
CesiumMath) {
'use strict';
/**
* A ParticleEmitter that emits particles within a sphere.
* Particles will be positioned randomly within the sphere and have initial velocities emanating from the center of the sphere.
*
* @alias SphereEmitter
* @constructor
*
* @param {Number} [radius=1.0] The radius of the sphere in meters.
*/
function SphereEmitter(radius) {
radius = defaultValue(radius, 1.0);
//>>includeStart('debug', pragmas.debug);
Check.typeOf.number.greaterThan('radius', radius, 0.0);
//>>includeEnd('debug');
this._radius = defaultValue(radius, 1.0);
}
defineProperties(SphereEmitter.prototype, {
/**
* The radius of the sphere in meters.
* @memberof SphereEmitter.prototype
* @type {Number}
* @default 1.0
*/
radius : {
get : function() {
return this._radius;
},
set : function(value) {
//>>includeStart('debug', pragmas.debug);
Check.typeOf.number.greaterThan('value', value, 0.0);
//>>includeEnd('debug');
this._radius = value;
}
}
});
/**
* Initializes the given {Particle} by setting it's position and velocity.
*
* @private
* @param {Particle} particle The particle to initialize
*/
SphereEmitter.prototype.emit = function(particle) {
var theta = CesiumMath.randomBetween(0.0, CesiumMath.TWO_PI);
var phi = CesiumMath.randomBetween(0.0, CesiumMath.PI);
var rad = CesiumMath.randomBetween(0.0, this._radius);
var x = rad * Math.cos(theta) * Math.sin(phi);
var y = rad * Math.sin(theta) * Math.sin(phi);
var z = rad * Math.cos(phi);
particle.position = Cartesian3.fromElements(x, y, z, particle.position);
particle.velocity = Cartesian3.normalize(particle.position, particle.velocity);
};
return SphereEmitter;
});