$(document.observe('mousemove', function(e) {
	calculateBGPosition(e);
}));
var WindowSize = Class.create({
    width: window.innerWidth || (window.document.documentElement.clientWidth || window.document.body.clientWidth),
    height: window.innerHeight || (window.document.documentElement.clientHeight || window.document.body.clientHeight)
});
var windowSize = new WindowSize;
var plane1Movement = 40;
var plane2Movement = 25;
var plane3Movement = 5;

var plane1StartPosition = 715;
var plane2StartPosition = -167;
var plane3StartPosition = -190;

function calculateBGPosition (e) {
	
	width = windowSize.width;
	var mouseX = e.pointerX(); 
    
    var plane1EndPosition = 0;
    var plane2EndPosition = 0;
    var plane3EndPosition = 0;
    
    var distanceDivision = (mouseX / width);
    var percentage = distanceDivision * 100;
    if(percentage >= 50)
    {
    	var finalDistanceDivision = ((percentage - 50) / 50);
		var plane1EndPosition = calculateEndPositionRight(plane1Movement, finalDistanceDivision, plane1StartPosition);
	    var plane2EndPosition = calculateEndPositionRight(plane2Movement, finalDistanceDivision, plane2StartPosition);
	    var plane3EndPosition = calculateEndPositionRight(plane3Movement, finalDistanceDivision, plane3StartPosition); 	
    }
    else
    {
    	var finalDistanceDivision = (50 - percentage) / 50;
 		var plane1EndPosition = calculateEndPositionLeft(plane1Movement, finalDistanceDivision, plane1StartPosition);
	    var plane2EndPosition = calculateEndPositionLeft(plane2Movement, finalDistanceDivision, plane2StartPosition);
	    var plane3EndPosition = calculateEndPositionLeft(plane3Movement, finalDistanceDivision, plane3StartPosition); 	   	
    }
    setEndPosition($('plane1'), plane1EndPosition);
    setEndPosition($('plane2'), plane2EndPosition);
    setEndPosition($('plane3'), plane3EndPosition);
    
}
function calculateEndPositionRight(planeMovement, distanceDivision, planeStartPosition) {
	return planeStartPosition - (planeMovement * distanceDivision);
}
function calculateEndPositionLeft(planeMovement, distanceDivision, planeStartPosition) {
	return planeStartPosition + (planeMovement * distanceDivision);
}
function setEndPosition(plane, planeEndPosition) {
	plane.setStyle({'left': planeEndPosition + 'px'});
}