var dat = new Array(63)
dat[0] = "../slide/slide00.jpg";
dat[1] = "../slide/slide01.jpg";
dat[2] = "../slide/slide02.jpg";
dat[3] = "../slide/slide03.jpg";
dat[4] = "../slide/slide04.jpg";
dat[5] = "../slide/slide05.jpg";
dat[6] = "../slide/slide06.jpg";
dat[7] = "../slide/slide07.jpg";
dat[8] = "../slide/slide08.jpg";
dat[9] = "../slide/slide09.jpg";
dat[10] = "../slide/slide10.jpg";
dat[11] = "../slide/slide11.jpg";
dat[12] = "../slide/slide12.jpg";
dat[13] = "../slide/slide13.jpg";
dat[14] = "../slide/slide14.jpg";
dat[15] = "../slide/slide15.jpg";
dat[16] = "../slide/slide16.jpg";
dat[17] = "../slide/slide17.jpg";
dat[18] = "../slide/slide18.jpg";
dat[19] = "../slide/slide19.jpg";
dat[20] = "../slide/slide20.jpg";
dat[21] = "../slide/slide21.jpg";
dat[22] = "../slide/slide22.jpg";
dat[23] = "../slide/slide23.jpg";
dat[24] = "../slide/slide24.jpg";
dat[25] = "../slide/slide25.jpg";
dat[26] = "../slide/slide26.jpg";
dat[27] = "../slide/slide27.jpg";
dat[28] = "../slide/slide28.jpg";
dat[29] = "../slide/slide29.jpg";
dat[30] = "../slide/slide30.jpg";
dat[31] = "../slide/slide31.jpg";
dat[32] = "../slide/slide32.jpg";
dat[33] = "../slide/slide33.jpg";
dat[34] = "../slide/slide34.jpg";
dat[35] = "../slide/slide35.jpg";
dat[36] = "../slide/slide36.jpg";
dat[37] = "../slide/slide37.jpg";
dat[38] = "../slide/slide38.jpg";
var n = dat.length;
var idx = 0;
var i;

function slideshow() {
  idx = Math.floor(Math.random() * (n-2) + 1); 
  var obj = new Image;
  obj.src = dat[idx];
  setTimeout("next()", 2000)
}

function next() {
  blendimage('slide','image',dat[idx],500)
  var adj = Math.floor(Math.random() * (n-2) + 1); 
  idx = (idx + adj) % n
  var obj = new Image;
  obj.src = dat[idx];
}

function opacity(id, opacStart, opacEnd, millisec) {
  //speed for each frame
  var speed = Math.round(millisec / 100);
  var timer = 0;

  //determine the direction for the blending, if start and end are the same nothing happens
  if(opacStart > opacEnd) {
    for(i = opacStart; i >= opacEnd; i--) {
      setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
      timer++;
    }
  } else if(opacStart < opacEnd) {
    for(i = opacStart; i <= opacEnd; i++)
      {
      setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
      timer++;
    }
  }
}


function changeOpac(opacity, id) {
  //change the opacity for different browsers
  var object = document.getElementById(id).style; 
  object.opacity = (opacity / 100);
  object.MozOpacity = (opacity / 100);
  object.KhtmlOpacity = (opacity / 100);
  object.filter = "alpha(opacity=" + opacity + ")";
}

function shiftOpacity(id, millisec) {
  //if an element is invisible, make it visible, else make it ivisible
  if(document.getElementById(id).style.opacity == 0) {
    opacity(id, 0, 100, millisec);
  } else {
    opacity(id, 100, 0, millisec);
  }
}

function blendimage(divid, imageid, imagefile, millisec) {
  var speed = Math.round(millisec / 100);
  var timer = 0;
  
  //set the current image as background
  document.getElementById(divid).style.backgroundImage = "url(" + document.getElementById(imageid).src + ")";
  
  //make image transparent
  changeOpac(0, imageid);
  
  //make new image
  document.getElementById(imageid).src = imagefile;


  //fade in image
  for(i = 0; i <= 100; i++) {
    setTimeout("changeOpac(" + i + ",'" + imageid + "')",(timer * speed));
    timer++;
  }
  setTimeout("next()", 5000)
}

function currentOpac(id, opacEnd, millisec) {
  //standard opacity is 100
  var currentOpac = 100;
  
  //if the element has an opacity set, get it
  if(document.getElementById(id).style.opacity < 100) {
    currentOpac = document.getElementById(id).style.opacity * 100;
  }

  //call for the function that changes the opacity
  opacity(id, currentOpac, opacEnd, millisec)
}