package
{
	import flash.display.Sprite;
	import flash.events.Event;
	
	public class animation_ch09_Distance extends Sprite
	{
		private var ball1:animation_ch09_Ball;
		private var ball2:animation_ch09_Ball;
		
		public function animation_ch09_Distance()
		{
			init();
		}
		
		private function init():void
		{
			ball1 = new animation_ch09_Ball();
			addChild(ball1);
			ball1.x = stage.stageWidth / 2;
			ball1.y = stage.stageHeight / 2;
			
			ball2 = new animation_ch09_Ball();
			addChild(ball2);
			ball2.startDrag(true);
			
			addEventListener(Event.ENTER_FRAME, onEnterFrame);			
		}
		
		private function onEnterFrame(event:Event):void
		{
			var dx:Number = ball2.x - ball1.x;
			var dy:Number = ball2.y - ball1.y;
			var dist:Number = Math.sqrt(dx * dx + dy * dy);
			// default ball diameter is 80 (radius is 40)
			if(dist < 80)
			{
				trace("hit");
			}
		}
	}
}