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