harmonicOscillator comparison.js

// harmonicOscillator.js 
// 
// Created by Philip Rosedale on May 5, 2015 
// Copyright 2015 High Fidelity, Inc.
//
// An object moves around the edge of a disc while changing color.
// The script is continuously updating position, velocity, rotation, and color.
// The movement should appear perfectly smooth to someone else, 
// provided their network connection is good.  
//
// Distributed under the Apache License, Version 2.0.
// See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
//

var fwd    = Camera.orientation.fwd;
var center = Camera.position.add(fwd.multiply(3.0));
var axis   = Vec3.UP;
var amplitude = 1.0;
var omega = 2.0 * Math.PI / 32.0; // radians/sec

var ball = new Entity({   
    type: "Box",
    position: center,
    dimensions: new Vec3(0.1, 0.1, 0.1);
    color: new Color("#ff00ff"),
    dynamic: false,
    collisionless: true
});

var disc = new Entity({
    type: "Sphere",
    position: center,
    dimensions: new Vec3(0.8, 1.0 / 20, 0.8).multiply(amplitude),
    color: new Color("#7f7f7f")
});

var time = 0.0; 

function update(deltaTime) {
    time += deltaTime;
    var tw = time * omega;
    var s = Math.sin(tw);
    var c = Math.cos(tw);
    var angle = tw * 180.0 / Math.PI; // degrees
    var factor = 0.5 * (s + 1.0);
    ball.update({
        color: new Vec3(factor, 1.0 - factor, 0.0).toColor(),
        position: new Vec3(s, 0.0, c).multiply(amplitude).add(center),
        velocity: new Vec3(c, 0.0, -s).multiply(amplitude * omega),
        rotation: axis.toRotation(angle),
    });
}

function scriptEnding() {
    ball.destroy();
    disc.destroy();
}

Script.update.connect(update);
Script.scriptEnding.connect(scriptEnding);