//Import TweenMax
import gs.*;
import gs.plugins.*;
 
//Number of items in each circles
const OUTER_ITEMS:uint = 60;
const MIDDLE_ITEMS:uint = 40;
const INNER_ITEMS:uint = 20;
 
//The radiuses and floor for each carousel (floor is not constant since we change it
//during the animation)
const OUTER_RADIUS_X:Number = 250;
const OUTER_RADIUS_Z:Number = 140;
 
const MIDDLE_RADIUS_X:Number = 150;
const MIDDLE_RADIUS_Z:Number = 80;
 
const INNER_RADIUS_X:Number = 80;
const INNER_RADIUS_Z:Number = 40;
 
//The floor for each item
var floor:Number = 100;
 
//Set the focal length
var focalLength:Number = 350;
 
//Set the vanishing point
var vanishingPointX:Number = stage.stageWidth / 2;
var vanishingPointY:Number = stage.stageHeight / 2;
 
//This array will contains all the items in the carousels
var myItems:Array = new Array();
 
//The angle speed for the items
var angleSpeed:Number = 0.02;
 
//Call the function that initializes the carousels
initializeCarousels();
 
//This function creates and positions the carousels
function initializeCarousels():void {
 
        //We use the function "createCarousel()" to create and position the carousels.
        //We pass the number of items and the radiuses as parameters
        createCarousel(OUTER_ITEMS, OUTER_RADIUS_X, OUTER_RADIUS_Z);
        createCarousel(MIDDLE_ITEMS, MIDDLE_RADIUS_X, MIDDLE_RADIUS_Z);
        createCarousel(INNER_ITEMS, INNER_RADIUS_X, INNER_RADIUS_Z);
 
        //Now that we have all the carousels ready, we can start to animate them
        //using the ENTER_FRAME listener.
        addEventListener(Event.ENTER_FRAME, rotateCarousels);
}
 
//This function creates a single carousel.
function createCarousel(numberOfItems:uint, xRadius:Number, zRadius:Number) {
 
        //Calculate the angle difference between the items (in radians)
        var angleDifference:Number = Math.PI * (360 / numberOfItems) / 180;
 
        //This loop creates and positions the carousel items
        for (var i:uint = 0; i < numberOfItems; i++) {
 
                //Create a new item
                var myItem:MyItem = new MyItem();
 
                //Make the item a bit transparent
                myItem.alpha = 0.6;
 
                //Get the starting angle for the item
                var startingAngle:Number = angleDifference * i;
 
                //Position the item
                myItem.xpos3D = xRadius * Math.cos(startingAngle);
                myItem.zpos3D = zRadius * Math.sin(startingAngle);
                myItem.ypos3D = floor;
 
                //Set a "currentAngle" attribute for the item
                myItem.currentAngle = startingAngle;
 
                //Save the x and z radiuses for this item (needed in the animation)
                myItem.xRadius = xRadius;
                myItem.zRadius = zRadius;
 
                //Calculate the scale ratio for the item (the further the image -> the smaller the scale)
                var scaleRatio = focalLength/(focalLength + myItem.zpos3D);
 
                //Scale the item according to the scale ratio
                myItem.scaleX = myItem.scaleY = scaleRatio;
 
                //Position the item to the stage (from 3D to 2D coordinates)
                myItem.x = vanishingPointX + myItem.xpos3D * scaleRatio;
                myItem.y = vanishingPointY + myItem.ypos3D * scaleRatio;
 
                //Add the item to the array
                myItems.push(myItem);
 
                //Add the item to the stage
                addChild(myItem);
        }
}

//This function rotates all the carousels
function rotateCarousels(e:Event):void {
 
        //Loop through all the items
        for (var i:uint = 0; i < myItems.length; i++) {
 
                //Save the item to a local variable
                var myItem:MyItem = (MyItem)(myItems[i]);
 
                //Update the current angle for the item
                myItem.currentAngle += angleSpeed;
 
                //Set a new 3D position for the item
                myItem.xpos3D=myItem.xRadius*Math.cos(myItem.currentAngle);
                myItem.zpos3D=myItem.zRadius*Math.sin(myItem.currentAngle);
 
                //The new 3D y coordinate can be from -200 to 200
                myItem.ypos3D= (mouseY*2 / stage.stageHeight) * 200 - 200;
 
                //Calculate a scale ratio
                var scaleRatio = focalLength/(focalLength + myItem.zpos3D);
 
                //Scale the item according to the scale ratio
                myItem.scaleX=myItem.scaleY=scaleRatio;
 
                //Update the item's 2D coordinates (tween to new y coordinates).
                myItem.x=vanishingPointX+myItem.xpos3D*scaleRatio;
                TweenMax.to(myItem, 0.5, {y: vanishingPointY+myItem.ypos3D*scaleRatio});
 
        }
        //Call the function that sorts the items so they overlap each other correctly
        sortZ();
}
 
//This function sorts the items so they overlap each others correctly
function sortZ():void {
 
        //Sort the array so that the item which has the highest 
        //z position (= furthest away) is first in the array
        myItems.sortOn("zpos3D", Array.NUMERIC | Array.DESCENDING);
 
        //Set new child indexes for the items
        for (var i:uint = 0; i < myItems.length; i++) {
                setChildIndex(myItems[i], i);
        }
}