This plugin patches Impact to use RequestAnimationFrame which improves the performance of Impact games running on Win8.

raf.js

ig.module(
	'plugins.raf'
)
.requires(
	'impact.system'
)
.defines(function(){

(function () {
    var lastTime = 0;
    var vendors = ['ms', 'moz', 'webkit', 'o'];
    for (var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
        window.requestAnimationFrame = window[vendors[x] + 'RequestAnimationFrame'];
        window.cancelAnimationFrame =
            window[vendors[x] + 'CancelAnimationFrame'] || window[vendors[x] + 'CancelRequestAnimationFrame'];
    }
    console.log("window.requestAnimationFrame", window.requestAnimationFrame);
    if (!window.requestAnimationFrame)
        window.requestAnimationFrame = function (callback, element) {
            var currTime = new Date().getTime();
            var timeToCall = Math.max(0, 16 - (currTime - lastTime));
            var id = window.setTimeout(function () { callback(currTime + timeToCall); },
                timeToCall);
            lastTime = currTime + timeToCall;
            return id;
        };

    if (!window.cancelAnimationFrame)
        window.cancelAnimationFrame = function (id) {
            clearTimeout(id);
        };
}());

ig.System.inject({
	nextFrameRequested: false,

    stopRunLoop: function () {
        //~ clearInterval( this.intervalId );
        this.running = false;
    },


    startRunLoop: function () {
        //~ this.stopRunLoop();
        //~ this.intervalId = setInterval( this.run.bind(this), 1000 / this.fps );
        if (!this.nextFrameRequested) {
            this.runBound = this.run.bind(this);
            this.nextFrameRequested = true;
            window.requestAnimationFrame(this.runBound);
        }
        this.running = true;
    },

    run: function () {
        if (this.running) {
            this.nextFrameRequested = true;
            window.requestAnimationFrame(this.runBound);
        }
        else {
            this.nextFrameRequested = false;
            return;
        }

        ig.Timer.step();
        this.tick = this.clock.tick();

        this.delegate.run();
        ig.input.clearPressed();

        if (this.newGameClass) {
            this.setGameNow(this.newGameClass);
            this.newGameClass = null;
        }
    }
});

});