var cache = [];
var imgoverlays = [];
var imagenames= ['research','transform','environ','learning'];
// overcoords is a two-dimensional array, primary dimension has one entry for each image overlay, 2nd dimension gives [width,height,leftoffset,topoffset]
var overcoords = [[55,55,"858px","257px"],[55,55,"859px","258px"],[55,55,"860px","257px"],[55,55,"858px","257px"]];
var mainanim;
var runanim=false;
var showingimage=0;
var queuedimage=1;
var maximage=0;
var showimagefor = 5000; // pause between image changes in milliseconds
var fadetime = 400; // time the fade between images takes in milliseconds

  // arguement is array of filenames in the 'images' subdirectory
function preLoadImages(names)  {
    maximage = names.length;
    for (var i = 0; i < maximage; i++) {
      var cacheImage = document.createElement('img');
      cacheImage.src = 'images/' + names[i] + '.png';
      cache.push(cacheImage);
    }
}

function makeactive() {
//  clearTimeout(mainanim); // halt animation while mouse is over the main image
//  runanim=false;
  $('#homeoverlay').show();
}
function killactive() {
  $('#homeoverlay').hide();
//  mainanim = setTimeout(nextimage,showimagefor);
//  runanim=true;
}
function nextimage() {
	showingimage = queuedimage;
	if (queuedimage < (maximage-1)) queuedimage++; else queuedimage=0;
//		alert("show: "+showingimage + " queue: "+queuedimage + " max: " + maximage);
	$('#nextimage').fadeIn(fadetime,function() {	
	$('#showimage').attr('src',cache[showingimage].src);
//	$('#overimage').attr('width',overcoords[showingimage][0]);
//	$('#overimage').attr('height',overcoords[showingimage][1]);
	$('#mainclick').attr('href',imagenames[showingimage] + ".php");
	$('#overclick').attr('href',imagenames[showingimage] + ".php");
	$('#homeoverlay').css('left',overcoords[showingimage][2]);
	$('#homeoverlay').css('top',overcoords[showingimage][3]);
	$('#nextimage').hide();
	$('#fadeimage').attr('src',cache[queuedimage].src);	
	mainanim = setTimeout(nextimage,showimagefor);
}	);
}

$(document).ready(function() {
  preLoadImages(imagenames);
  runanim=true;
	mainanim = setTimeout(nextimage,showimagefor);

});