/**
 * Parallax Scrolling 
 *   
 * Author: Richard Shepherd
 * 		   www.richardshepherd.com
 * 		   @richardshepherd   
 */

$(document).ready(function(){
						
	$window = $(window);
	
	$('[data-type]').each(function() {	
		$(this).data('offsetY', parseInt($(this).attr('data-offsetY')));
		$(this).data('Xposition', $(this).attr('data-Xposition'));
		$(this).data('speed', $(this).attr('data-speed'));
	});
	
	$('div.story[data-type="background"]').each(function(){
	
		var $self = $(this),
			offsetCoords = $self.offset(),
			topOffset = offsetCoords.top;
		
	    $(window).scroll(function() {
	
			if ( ($window.scrollTop() + $window.height()) > (topOffset) &&
				 ( (topOffset + $self.height()) > $window.scrollTop() ) ) {
	
				var yPos = -($window.scrollTop() / $self.data('speed')); 
				
				if ($self.data('offsetY')) {
					yPos += $self.data('offsetY');
				}
				
				var coords = '50% '+ yPos + 'px';

				$self.css({ backgroundPosition: coords });	
			
			}; 
	
		}); 
			
	});	

});