円運動

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

// forked from _wonder's Math.sin()を使って上下運動
package {
    import flash.display.Sprite;
    import flash.events.Event;
    
    public class Bobbing extends Sprite {
    		private var ball:Ball;
    		private var angle:Number = 0;
    		private var centerX:Number = 200;
    		private var centerY:Number = 200;
    		private var radius:Number = 50;
    		private var speed:Number = 0.1;
    		
        public function Bobbing() {
            init();
        }
        
        private function init():void {
        		ball = new Ball();
        		addChild( ball );
        		ball.x = 0;
        		addEventListener(Event.ENTER_FRAME, onEnterFrame);
        }
        
        private function onEnterFrame(e:Event):void {
        		ball.x = centerX + Math.sin(angle) * radius;
        		ball.y = centerY + Math.cos(angle) * radius;
        		angle += speed;
        }
    }
}

import flash.display.Sprite;

class Ball extends Sprite {
	private var _radius:Number;
	private var _color:uint;
	
	public function Ball(radius:Number=40,color:uint=0Xff0000) {
		_radius = radius;
		_color = color;
		init();
	}
	
	private function init():void {
		graphics.beginFill(_color);
		graphics.drawCircle(0, 0, _radius);
		graphics.endFill();
	}
}