// JavaScript Document
function initImgRotation() {
  // create rotating image objects here 
  // arguments: image name, rotation speed
  var rotator1 = new rotateImgObj('img1',10000);
  // add the images to rotate into that image object  
  rotator1.addImages("thetis_01.jpg","thetis_02.jpg","thetis_03.jpg");
  rotator1.rotate();
  
  var rotator2 = new rotateImgObj('img2',8000);
  rotator2.addImages("crew_01.jpg","crew_02.jpg","crew_03.jpg");
  rotator2.rotate();
 
   var rotator3 = new rotateImgObj('img3',7000);
  rotator3.addImages("story_01.jpg","story_02.jpg","story_03.jpg");
  rotator3.rotate();

  
  rotateImgObj.start();  
}

// If all the images you wish to display are in the same location, you can specify the path here 
rotateImgObj.imagesPath = "img/main/";

// no need to edit code below 
/////////////////////////////////////////////////////////////////////
rotateImgObjs = []; // holds all rotating image objects defined
// constructor 
function rotateImgObj(nm,s) {
  this.speed=s; this.ctr=0; this.timer=0;  
  this.imgObj = document.images[nm]; // get reference to the image object
  this.index = rotateImgObjs.length; rotateImgObjs[this.index] = this;
  this.animString = "rotateImgObjs[" + this.index + "]";
}

rotateImgObj.prototype = {
  addImages: function() { // preloads images
    this.imgObj.imgs = [];
    for (var i=0; i<arguments.length; i++) {
      this.imgObj.imgs[i] = new Image();
      this.imgObj.imgs[i].src = rotateImgObj.imagesPath + arguments[i];
    }
  },

  rotate: function() {
    if (this.ctr < this.imgObj.imgs.length-1) this.ctr++;
    else this.ctr = 0;
    this.imgObj.src = this.imgObj.imgs[this.ctr].src;
  }
}

// sets up rotation for all defined rotateImgObjs
rotateImgObj.start = function() {
  for (var i=0; i<rotateImgObjs.length; i++) 
    rotateImgObjs[i].timer = setInterval(rotateImgObjs[i].animString + ".rotate()", rotateImgObjs[i].speed);                     
}