Add growth script to examples

examples/growth.js

@@ -0,0 +1,75 @@
+//
+//  growth.js
+//
+//  Created by Zachary Pomerantz 11/2/2015.
+//  Copyright 2015 High Fidelity, Inc.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+var RADIUS = 5;
+var LIFETIME = 6000;
+
+var size = 1;
+var center = MyAvatar.position;
+var positions = [
+    Vec3.sum(center, Vec3.multiply(RADIUS, Vec3.FRONT)),
+    Vec3.sum(center, Vec3.multiply(-RADIUS, Vec3.FRONT)),
+    Vec3.sum(center, Vec3.multiply(RADIUS, Vec3.RIGHT)),
+    Vec3.sum(center, Vec3.multiply(-RADIUS, Vec3.RIGHT)),
+    Vec3.sum(center, Vec3.multiply(RADIUS, Vec3.UP)),
+    Vec3.sum(center, Vec3.multiply(-RADIUS, Vec3.UP)),
+];
+
+var spheres = map(positions, getSphere);
+
+Script.update.connect(function(delta) {
+    size += delta; // grow by 1 unit/s
+    each(spheres, function(sphere) {
+        Entities.editEntity(sphere, { dimensions: getDimensions(size) });
+    });
+});
+Script.scriptEnding.connect(function() {
+    each(spheres, function(sphere) {
+        Entities.deleteEntity(sphere);
+    });
+});
+
+// Entity helpers
+
+function getSphere(position) {
+    return Entities.addEntity({
+        type: 'Sphere',
+        position: position,
+        dimensions: getDimensions(size),
+        color: getColor(),
+        gravity: Vec3.ZERO,
+        lifetime: LIFETIME,
+        ignoreCollisions: true,
+    });
+}
+
+function getDimensions(size) {
+    return { x: size, y: size, z: size };
+}
+
+function getColor() {
+    return { red: getValue(), green: getValue(), blue: getValue() };
+    function getValue() { return Math.floor(Math.random() * 255); }
+}
+
+// Functional helpers
+
+function map(list, iterator) {
+    var result = [];
+    for (var i = 0; i < list.length; i++) {
+        result.push(iterator(list[i], i, list));
+    }
+    return result;
+}
+
+function each(list, iterator) {
+    for (var i = 0; i < list.length; i++) {
+        iterator(list[i], i, list);
+    }
+}