PIXI.js StressTest Class

/**
 * @author Mat Groves http://matgroves.com/
 */
var PIXI = PIXI || {};


PIXI.StressTest = function(callback)
{

    this.callback = callback;
    this.stage = new PIXI.Stage(0x123456);
    this.renderer = new PIXI.CanvasRenderer(500, 500);
    document.body.appendChild(this.renderer.view);
    this.renderer.view.style.position = "absolute";
    this.renderer.view.style.left = "-500px";

    this.duration = 3;

    var scope = this;
    var canvas = document.createElement("canvas");
    canvas.width = 52
    canvas.height = 74
    canvas.context = canvas.getContext("2d");
    canvas.context.fillStyle="#FF0000";
    canvas.context.fillRect(0,0,52,74);

    this.texture = PIXI.Texture.fromCanvas(canvas);
    scope.begin();
    // this.texture.baseTexture.addEventListener( 'loaded', function(){ scope.begin()} );

    this.frameRate = [];
}

// constructor
PIXI.StressTest.constructor = PIXI.StressTest;

PIXI.StressTest.prototype.begin = function()
{
    this.testSprites = [];
    for (var i=0; i < 300; i++)
    {
        var bunny = new PIXI.Sprite(this.texture);
        bunny.anchor.x = 0.5;
        bunny.anchor.y = 0.5;
        bunny.alpha = .5;
        this.stage.addChild(bunny);
        bunny.position.x = 50 + Math.random() * 400;
        bunny.position.y = 50 + Math.random() * 400;

        this.testSprites.push(bunny);
    };

    this.renderer.render(this.stage);

    this.startTime = Date.now();
    this.lastTime = Date.now();

    var scope = this
    requestAnimFrame(function(){scope.update()});
}

PIXI.StressTest.prototype.update = function()
{
    var currentTime = Date.now();

    for (var i=0; i < this.testSprites.length; i++) {
      this.testSprites[i].rotation += 0.3;
    };

    this.renderer.render(this.stage);

    var diff = currentTime - this.lastTime;
    diff *= 0.06;

    //diff *= 60;

    this.frameRate.push(diff);

    this.lastTime = currentTime;

    var elapsedTime = currentTime - this.startTime;

    if(elapsedTime < this.duration * 1000)
    {
        var scope = this
        requestAnimFrame(function(){scope.update()});

    }
    else
    {

        document.body.removeChild(this.renderer.view);

        this.renderer = null;

        this.result = this.frameRate.length/this.duration;


        if(this.callback)this.callback(this.result);
    }

}