text: 'use strict';
  
  var Backbone = require('Backbone');
  var _ = require('underscore');
  
  var WorldModel = Backbone.Model.extend({
  
      defaults: {
          height: 0,
          width: 0,
          // refresh rate in MS
          frameRate: 30
      },
  
      particles: [],
  
      initialize: function() {
          this.timer = setInterval(_.bind(this.tick, this), this.get('frameRate'));
      },
  
      tick: function() {
          this.trigger('tick');
      }
  });
  
  module.exports = WorldModel;
  