var eyeballWidth=40;
var eyeballHeight=40;
var irisWidth=13;
var irisHeight=13;
var centerX=0;
var centerY=0;
var height=1700;
//var backLogoImg=new Image();

function initImages() {
	var backLogoImg=document.getElementById("backLogo");	
	
	var logoImg=document.getElementById("logo");
	logoImg.src=backLogoImg.src;	
	initEyes();

	document.onmousemove=moveHandler;
	window.onresize=initEyes;
}

function initEyes(){
setCenter();
animateEyes(100,100);
}

function setCenter(){
	var img=document.getElementById("logo");	
	var parentLocation= new Array(2);
	parentLocation[0]=0;
	parentLocation[1]=0;
	parentLocation=findPos(img);	//determine the coordinates of the logo
	centerX=parentLocation[0]+47;			
	centerY=parentLocation[1]+20;	
}

function moveHandler(evt) {
	if (!evt) {
		evt=window.event;
	}
	animateEyes(evt.clientX, evt.clientY);
}

function animateEyes(xPos, yPos) {
	var irisImg=document.getElementById("iris").style;		
	var deltaX=((xPos-centerX)/Math.sqrt((xPos-centerX)*(xPos-centerX)+(yPos-centerY)*(yPos-centerY)+height*height))*eyeballWidth/2;
	var deltaY=((yPos-centerY)/Math.sqrt((xPos-centerX)*(xPos-centerX)+(yPos-centerY)*(yPos-centerY)+height*height))*eyeballHeight/2;
	var maxDeltaR=(eyeballWidth-irisWidth)/2-7;
	var deltaR=Math.sqrt(deltaX*deltaX+deltaY*deltaY);
	if (deltaR>maxDeltaR){
		deltaX=deltaX/deltaR*maxDeltaR;
		deltaY=deltaY/deltaR*maxDeltaR;
	}
		
	irisImg.left=(centerX+deltaX-irisWidth/2)+"px";
	
	irisImg.top=(centerY+deltaY-irisHeight/2+1)+"px";

}

//THANKS to www.quirksmode.org for generously providing this free function below (findPos)
function findPos(obj) {
	var curleft = curtop = 0;
	if (obj.offsetParent) {
		curleft = obj.offsetLeft
		curtop = obj.offsetTop
		while (obj = obj.offsetParent) {
			curleft += obj.offsetLeft
			curtop += obj.offsetTop
		}
	}
	return [curleft,curtop];
}

//window.onload=initImages;