Add existing to tracked

node_modules/@cesium/engine/Source/Scene/CircleEmitter.js

@@ -0,0 +1,61 @@
+import Cartesian3 from "../Core/Cartesian3.js";
+import Check from "../Core/Check.js";
+import CesiumMath from "../Core/Math.js";
+
+/**
+ * A ParticleEmitter that emits particles from a circle.
+ * Particles will be positioned within a circle and have initial velocities going along the z vector.
+ *
+ * @alias CircleEmitter
+ * @constructor
+ *
+ * @param {number} [radius=1.0] The radius of the circle in meters.
+ */
+function CircleEmitter(radius) {
+  radius = radius ?? 1.0;
+
+  //>>includeStart('debug', pragmas.debug);
+  Check.typeOf.number.greaterThan("radius", radius, 0.0);
+  //>>includeEnd('debug');
+
+  this._radius = radius ?? 1.0;
+}
+
+Object.defineProperties(CircleEmitter.prototype, {
+  /**
+   * The radius of the circle in meters.
+   * @memberof CircleEmitter.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 {@link Particle} by setting it's position and velocity.
+ *
+ * @private
+ * @param {Particle} particle The particle to initialize.
+ */
+CircleEmitter.prototype.emit = function (particle) {
+  const theta = CesiumMath.randomBetween(0.0, CesiumMath.TWO_PI);
+  const rad = CesiumMath.randomBetween(0.0, this._radius);
+
+  const x = rad * Math.cos(theta);
+  const y = rad * Math.sin(theta);
+  const z = 0.0;
+
+  particle.position = Cartesian3.fromElements(x, y, z, particle.position);
+  particle.velocity = Cartesian3.clone(Cartesian3.UNIT_Z, particle.velocity);
+};
+export default CircleEmitter;