Coder, Maker, Gamer (he/him) 🏳️‍🌈

11Aug 12

RocketBox - HTML5 Toolkit

I've create numerous HTML5 apps recently and each time I start a new one, I go through the same process getting all the core components in place. This takes an hour or so and once complete I can finally start working on the actual app. It's for this reason that I decided to create RocketBox - a html5 game/demo/app toolkit. It's essentially a blackbox that abstracts away a lot of the headaches and boring stuff that developers face when they start a new project.


  • Front-end player & UI for canvas based applications
  • Scaling handling
  • Fullscreen support
  • Events system
  • Render loop timer
  • Debug & logging system
  • Supports multiple apps per page

There are other benefits to this project too: future features can be added which an app will benefit from without having to touch it's code base (ie: fullscreen feature will implement the fullscreen API further down the line), the app's won't need updating, it just works. It also means that all your games/demos follow a uniform structure, making it nice and easy to implement in a blog etc (plus RocketBox also supports multiple instances per page).

View/Download: RocketBox Github Project (as always, I welcome pull requests! :)

The demo above demonstrates a basic app integrating with RocketBox, below you can see/download the code. All of the demos on this blog use RocketBox (even the older posts!), blogging was one of the main motives for creating the project!

var BouncingBall = function () {

 this.canvasContext  = undefined;
 this.events   = undefined;
 this.width    = 640;
 this.height   = 360;
 this.ballPosition  = {x:0, y: 0};
 this.ballDirection  = {x:1, y:1};
 this.ballRadius  = 30;


BouncingBall.prototype = {
 /* RocketBox will call this with the setup object */
 initalise: function (setup) {

  this.canvasContext  = setup.canvasContext;
  this.width    = setup.width;
  this.height   = setup.height;
  this.ballPosition  = {
   x: Math.round(this.width/2), 
   y: Math.round(this.height/2)

  this.events = setup.events;
  this.events.listen('APP:TICK', this.appLoop, this);
  this.events.listen('APP:RESIZE', this.resize, this);

 resize: function (eventData) {

  this.width   = eventData.width;
  this.height  = eventData.height;


 appLoop: function (cycle) {


 clearCanvas: function (opacity) {

  // 0.2 opacity to give trail effect
  this.canvasContext.fillStyle = "rgba(225,225,225,"+opacity+")";
  this.canvasContext.fillRect(0, 0, this.width, this.height);


 move: function (cycle) {

  this.ballPosition.x += ((cycle.dt/5) * this.ballDirection.x);
  this.ballPosition.y += ((cycle.dt/5) * this.ballDirection.y);

  if (this.ballPosition.x - this.ballRadius < 0) this.ballDirection.x = 1;
  if (this.ballPosition.x + this.ballRadius > this.width) this.ballDirection.x = -1;
  if (this.ballPosition.y - this.ballRadius < 0) this.ballDirection.y = 1;
  if (this.ballPosition.y + this.ballRadius > this.height) this.ballDirection.y = -1;

 render: function (cycle) {

  this.canvasContext.fillStyle = "rgb(40,40,40)";
  this.canvasContext.arc(this.ballPosition.x, this.ballPosition.y, this.ballRadius, 0, Math.PI*2, true);