/
ConeEmitter.js
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/
ConeEmitter.js
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import Cartesian3 from "../Core/Cartesian3.js";
import Check from "../Core/Check.js";
import defaultValue from "../Core/defaultValue.js";
import CesiumMath from "../Core/Math.js";
const defaultAngle = CesiumMath.toRadians(30.0);
/**
* A ParticleEmitter that emits particles within a cone.
* Particles will be positioned at the tip of the cone and have initial velocities going towards the base.
*
* @alias ConeEmitter
* @constructor
*
* @param {number} [angle=Cesium.Math.toRadians(30.0)] The angle of the cone in radians.
*/
function ConeEmitter(angle) {
this._angle = defaultValue(angle, defaultAngle);
}
Object.defineProperties(ConeEmitter.prototype, {
/**
* The angle of the cone in radians.
* @memberof CircleEmitter.prototype
* @type {number}
* @default Cesium.Math.toRadians(30.0)
*/
angle: {
get: function () {
return this._angle;
},
set: function (value) {
//>>includeStart('debug', pragmas.debug);
Check.typeOf.number("value", value);
//>>includeEnd('debug');
this._angle = value;
},
},
});
/**
* Initializes the given {Particle} by setting it's position and velocity.
*
* @private
* @param {Particle} particle The particle to initialize
*/
ConeEmitter.prototype.emit = function (particle) {
const radius = Math.tan(this._angle);
// Compute a random point on the cone's base
const theta = CesiumMath.randomBetween(0.0, CesiumMath.TWO_PI);
const rad = CesiumMath.randomBetween(0.0, radius);
const x = rad * Math.cos(theta);
const y = rad * Math.sin(theta);
const z = 1.0;
particle.velocity = Cartesian3.fromElements(x, y, z, particle.velocity);
Cartesian3.normalize(particle.velocity, particle.velocity);
particle.position = Cartesian3.clone(Cartesian3.ZERO, particle.position);
};
export default ConeEmitter;