ポインタを光源としたドロップシャドウ。

/**
 * Copyright pykgg476 ( http://wonderfl.net/user/pykgg476 )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/3NL8
 */

package {
	
import flash.display.Sprite;
	import flash.events.Event;
	import flash.filters.DropShadowFilter;

	public class AnimatedFilters extends Sprite
	{
		private var filter:DropShadowFilter;
		private var sprite:Sprite;
		public function AnimatedFilters()
		{
			init();
		}
		
		private function init():void{
			sprite = new Sprite();
			sprite.graphics.lineStyle(2);
			sprite.graphics.beginFill(0xffff00);
			sprite.graphics.drawRect(-50,-50,100,100);
			sprite.graphics.endFill();
			sprite.x = 200;
			sprite.y = 200;
			addChild(sprite);
			
			filter = new DropShadowFilter(0,0,0,1,20,20,.3);
			
			addEventListener(Event.ENTER_FRAME,onEnterFrame);
		}
		
		private function onEnterFrame(event:Event):void{
			var dx:Number = mouseX - sprite.x;
			var dy:Number = mouseY - sprite.y;
			
			filter.distance = -Math.sqrt(dx * dx + dy*dy)/10;
			filter.angle = Math.atan2(dy,dx) * 180/Math.PI;
			sprite.filters = [filter];
		}
	}
}