requestAnimationFrame support for ImpactJS

raf.patch

From 205a52304f57df249a17d839ae92d50ff3a70f46 Mon Sep 17 00:00:00 2001
From: KirbySaysHi <kirbysayshi@gmail.com>
Date: Fri, 30 Sep 2011 22:57:21 -0400
Subject: [PATCH] requestAnimationFrame. disable by setting ig.system.raf to
 false.

---
 lib/impact/impact.js |   14 +++++++++++++-
 lib/impact/system.js |   20 +++++++++++++++++---
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/lib/impact/impact.js b/lib/impact/impact.js
index 2d42dce..c1e3578 100644
--- a/lib/impact/impact.js
+++ b/lib/impact/impact.js
@@ -55,7 +55,19 @@ Function.prototype.bind = function(bind) {
 	};
 };
 
+// -----------------------------------------------------------------------------
+// requestAnimationFrame polyfill, paul irish.
 
+window.requestAnimFrame = (function(){
+	return  window.requestAnimationFrame   || 
+		window.webkitRequestAnimationFrame || 
+		window.mozRequestAnimationFrame    || 
+		window.oRequestAnimationFrame      || 
+		window.msRequestAnimationFrame     || 
+		function(/* function */ callback, /* DOMElement */ element){
+			window.setTimeout(callback, 1000 / 60);
+		};
+})();
 
 // -----------------------------------------------------------------------------
 // ig Namespace
diff --git a/lib/impact/system.js b/lib/impact/system.js
index 7c2ac2d..6df229f 100644
--- a/lib/impact/system.js
+++ b/lib/impact/system.js
@@ -14,11 +14,12 @@ ig.System = ig.Class.extend({
 	realWidth: 320,
 	realHeight: 240,
 	scale: 1,
+	raf: true,
 	
 	tick: 0,
-	intervalId: 0,
 	newGameClass: null,
 	running: false,
+	intervalId: 0,
 	
 	delegate: null,
 	clock: null,
@@ -76,15 +77,24 @@ ig.System = ig.Class.extend({
 	
 	
 	stopRunLoop: function() {
-		clearInterval( this.intervalId );
 		this.running = false;
+		if(this.raf !== true){
+			clearInterval( this.intervalId );
+		}
 	},
 	
 	
 	startRunLoop: function() {
 		this.stopRunLoop();
-		this.intervalId = setInterval( this.run.bind(this), 1000 / this.fps );
+
+		this.run = this.run.bind(this);
 		this.running = true;
+		
+		if(this.raf !== true){
+			this.intervalId = setInterval(this.run, 1000 / this.fps);
+		} else {
+			this.run();	
+		}
 	},
 	
 	
@@ -105,6 +115,10 @@ ig.System = ig.Class.extend({
 			this.setGameNow( this.newGameClass );
 			this.newGameClass = null;
 		}
+
+		if( this.raf === true && this.running === true ){
+			requestAnimFrame( this.run, this.canvas );	
+		}
 	},
 	
 	
-- 
1.7.4.4