package
{
	import flash.display.Sprite;
	import flash.events.Event;
	
	public class animation_ch09_Boxes extends Sprite
	{
		private var box:animation_ch09_Box;
		private var boxes:Array;
		private var gravity:Number = 0.2;
		
		public function animation_ch09_Boxes()
		{
			init();
		}
		
		private function init():void
		{
			boxes = new Array();
			createBox();
			addEventListener(Event.ENTER_FRAME, onEnterFrame);
		}
		
		private function onEnterFrame(event:Event):void
		{
			box.vy += gravity;
			box.y += box.vy
			if(box.y + box.height / 2 > stage.stageHeight)
			{
				box.y = stage.stageHeight - box.height / 2;
				createBox();
			}
			for(var i:uint = 0; i < boxes.length; i++)
			{
				if(box != boxes[i] && box.hitTestObject(boxes[i]))
				{
					box.y = boxes[i].y - boxes[i].height / 2 - box.height / 2;
					createBox();
				}
			}
		}
		
		private function createBox():void
		{
			box = new animation_ch09_Box(Math.random() * 40 + 10, Math.random() * 40 + 10);
			box.x = Math.random() * stage.stageWidth;
			addChild(box);
			boxes.push(box);
		}
	}
}