Add existing to tracked

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

@@ -0,0 +1,74 @@
+import Cartesian3 from "../Core/Cartesian3.js";
+import Check from "../Core/Check.js";
+import CesiumMath from "../Core/Math.js";
+
+const defaultDimensions = new Cartesian3(1.0, 1.0, 1.0);
+
+/**
+ * A ParticleEmitter that emits particles within a box.
+ * Particles will be positioned randomly within the box and have initial velocities emanating from the center of the box.
+ *
+ * @alias BoxEmitter
+ * @constructor
+ *
+ * @param {Cartesian3} dimensions The width, height and depth dimensions of the box.
+ */
+function BoxEmitter(dimensions) {
+  dimensions = dimensions ?? defaultDimensions;
+
+  //>>includeStart('debug', pragmas.debug);
+  Check.defined("dimensions", dimensions);
+  Check.typeOf.number.greaterThanOrEquals("dimensions.x", dimensions.x, 0.0);
+  Check.typeOf.number.greaterThanOrEquals("dimensions.y", dimensions.y, 0.0);
+  Check.typeOf.number.greaterThanOrEquals("dimensions.z", dimensions.z, 0.0);
+  //>>includeEnd('debug');
+
+  this._dimensions = Cartesian3.clone(dimensions);
+}
+
+Object.defineProperties(BoxEmitter.prototype, {
+  /**
+   * The width, height and depth dimensions of the box in meters.
+   * @memberof BoxEmitter.prototype
+   * @type {Cartesian3}
+   * @default new Cartesian3(1.0, 1.0, 1.0)
+   */
+  dimensions: {
+    get: function () {
+      return this._dimensions;
+    },
+    set: function (value) {
+      //>>includeStart('debug', pragmas.debug);
+      Check.defined("value", value);
+      Check.typeOf.number.greaterThanOrEquals("value.x", value.x, 0.0);
+      Check.typeOf.number.greaterThanOrEquals("value.y", value.y, 0.0);
+      Check.typeOf.number.greaterThanOrEquals("value.z", value.z, 0.0);
+      //>>includeEnd('debug');
+      Cartesian3.clone(value, this._dimensions);
+    },
+  },
+});
+
+const scratchHalfDim = new Cartesian3();
+
+/**
+ * Initializes the given {Particle} by setting it's position and velocity.
+ *
+ * @private
+ * @param {Particle} particle The particle to initialize.
+ */
+BoxEmitter.prototype.emit = function (particle) {
+  const dim = this._dimensions;
+  const halfDim = Cartesian3.multiplyByScalar(dim, 0.5, scratchHalfDim);
+
+  const x = CesiumMath.randomBetween(-halfDim.x, halfDim.x);
+  const y = CesiumMath.randomBetween(-halfDim.y, halfDim.y);
+  const z = CesiumMath.randomBetween(-halfDim.z, halfDim.z);
+
+  particle.position = Cartesian3.fromElements(x, y, z, particle.position);
+  particle.velocity = Cartesian3.normalize(
+    particle.position,
+    particle.velocity,
+  );
+};
+export default BoxEmitter;