crtrdg scene

entity module for games

Goals for crtrdg-scene:

  • A simple interface for handling different levels or screens of a game.

This is still an overly simple and naive implementation of a scene manager. Not quite ready for real use, but almost.


  • node.js
  • browserify / beefy
  • crtrdg-gameloop (or possibly another method of animating the canvas with requestAnimationFrame that emits update and draw events)

Getting started

Install node if you haven’t already.

Install browserify and beefy:

npm install -g browserify beefy


Create an index.html file:

<!DOCTYPE html>

  <title>crtrdg scene test</title>


<canvas id="game"></canvas>

<script src="./bundle.js"></script>

Create a game.js file:

var Game = require('crtrdg-gameloop')
var Mouse = require('crtrdg-mouse')
var scenes = require('crtrdg-scene')()

var game = new Game({

  canvas: 'game',

  width: '800',

  height: '400'


game.on('update', function (dt) {



game.on('draw', function (context) {



var mouse = new Mouse(game)

mouse.on('click', function (location) {

  if ( === 'first scene') scenes.set(sceneTwo)

  else scenes.set(scene)


var scene = scenes({

  name: 'first scene'


scene.on('start', sceneSwitch)

scene.on('draw', function (c) {

  console.log('scene one drawing')

  c.fillStyle = '#e1f23f'

  c.fillRect(0, 0, game.width, game.height)



var sceneTwo = scenes({

  name: 'second scene',

  backgroundColor: '#7def71'


sceneTwo.on('start', sceneSwitch)

sceneTwo.on('draw', function (c) {

  console.log('scene two drawing')

  c.fillStyle = sceneTwo.backgroundColor

  c.fillRect(0, 0, game.width, game.height)


function setMessage (text) {

  document.getElementById('scene-name').innerHTML = text


function sceneSwitch (scene) {




Purpose of crtrdg:

Almost every javascript game / animation library I’ve found bundles things like requestAnimationFrame polyfill, gameloop, entities, abstract drawing methods, keyboard/mouse input, vector math, and more into one entangled library. If I don’t like how the library handles just one of those components, I’m stuck with dead library weight, and sometimes it’s difficult to replace a library’s methods.

So what if each element of 2d games were broken up into it’s own modules / repositories?

With inspiration from voxel.js, crtrdg is a collection of javascript modules used for developing 2d games.

As I learned more about node.js, the core events module, and browserify, I realized the ideal api for making simple 2d games could be based on node’s events module. So you’ll see a lot of crtrdg modules exposing an api that includes .on('some event', function(){}), which seems to make a lot of sense for games.

Other crtrdg modules:


  • Fork this repository.
  • Create a branch for you changes.
  • Include tests if applicable.
  • Add/edit documentation for any changes.
  • Submit a pull request.