遠ざかるボール

/**
 * Copyright _wonder ( http://wonderfl.net/user/_wonder )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/6AQc
 */

// forked from _wonder's base
package {
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.events.KeyboardEvent;
    import flash.ui.Keyboard;
    
    public class Perspective extends Sprite {
        private var ball:Ball;
        private var xpos:Number = 0;
        private var ypos:Number = 0;
        private var zpos:Number = 0;
        private var fl:Number = 250;
        private var vpX:Number = stage.stageWidth / 2;
        private var vpY:Number = stage.stageHeight / 2;
        
        public function Perspective() {
            ball = new Ball();
            addChild( ball );
            addEventListener(Event.ENTER_FRAME, onEnterFrame);
            stage.addEventListener(KeyboardEvent.KEY_DOWN, onKeyDown);
        }
        
        private function onEnterFrame(e:Event):void {
            xpos = mouseX - vpX;
            ypos = mouseY - vpY;
            
            var scale:Number = fl / ( fl + zpos );
            ball.scaleX = ball.scaleY = scale;
            ball.x = vpX + xpos * scale;
            ball.y = vpX + ypos * scale;
        }
        
        private function onKeyDown(e:KeyboardEvent):void {
            if( e.keyCode == Keyboard.UP ){
                zpos += 5;
            } else if ( e.keyCode == Keyboard.DOWN ){
                zpos -= 5;
            }
        }
    }
}

import flash.display.Sprite;

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