var gblPhotoShufflerDivId = "desc";
var gblPhotoShufflerImgId = "descimg"; 
var gblPauseSeconds = 3;
var gblFadeSeconds = 1;
var gblRotations = 100;

// End Customization section

var gblDeckSize = gblImg.length;
var gblOpacity = 100;
var gblOnDeck = 0;
var gblStartImg;
var gblImageRotations = gblDeckSize * (gblRotations+1);

window.onload = photoShufflerLaunch;
  
function photoShufflerLaunch(){
	var theimg = document.getElementById(gblPhotoShufflerImgId);
	gblStartImg = theimg.src; // save away to show as final image

	document.getElementById(gblPhotoShufflerDivId).style.backgroundImage='url(' + gblImg[gblOnDeck] + ')';
	setTimeout("photoShufflerFade()",gblPauseSeconds*1000);
}

function photoShufflerFade(){
	var theimg = document.getElementById(gblPhotoShufflerImgId);
	
	// determine delta based on number of fade seconds
	// the slower the fade the more increments needed
	var fadeDelta = 100 / (30 * gblFadeSeconds);

	// fade top out to reveal bottom image
	if (gblOpacity < 2*fadeDelta ){
		gblOpacity = 100;
		// stop the rotation if we're done
		if (gblImageRotations < 1) return;
		photoShufflerShuffle();
		// pause before next fade
		setTimeout("photoShufflerFade()",gblPauseSeconds*1000);
	} else{
		gblOpacity -= fadeDelta;
		setOpacity(theimg,gblOpacity);
		setTimeout("photoShufflerFade()",30);  // 1/30th of a second
	}
}


function photoShufflerShuffle(){
	var thediv = document.getElementById(gblPhotoShufflerDivId);
	var theimg = document.getElementById(gblPhotoShufflerImgId);
	
	// copy div background-image to img.src
	theimg.src = gblImg[gblOnDeck];
	// set img opacity to 100
	setOpacity(theimg,100);

	// shuffle the deck
	gblOnDeck = ++gblOnDeck % gblDeckSize;
	// decrement rotation counter
	/*if (--gblImageRotations < 1){
		// insert start/final image if we're done
		gblImg[gblOnDeck] = gblStartImg;
	}*/

	// slide next image underneath
	thediv.style.backgroundImage='url(' + gblImg[gblOnDeck] + ')';
}


function setOpacity(obj, opacity) {
	opacity = (opacity == 100)?99.999:opacity;
    
	// IE/Win
	obj.style.filter = "alpha(opacity:"+opacity+")";
    
	// Safari<1.2, Konqueror
	obj.style.KHTMLOpacity = opacity/100;

	// Older Mozilla and Firefox
	obj.style.MozOpacity = opacity/100;

	// Safari 1.2, newer Firefox and Mozilla, CSS3
	obj.style.opacity = opacity/100;
}