3D速度・加速度

/**
 * Copyright _wonder ( http://wonderfl.net/user/_wonder )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/7FzI
 */

// forked from _wonder's base
package {
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.events.KeyboardEvent;
    import flash.ui.Keyboard;
    
    import flash.accessibility.Accessibility;
    public class Velocity3D extends Sprite {
    		private var ball:Ball;
    		private var xpos:Number = 0;
    		private var ypos:Number = 0;
    		private var zpos:Number = 0;
    		private var vx:Number = 0;
    		private var vy:Number = 0;
    		private var vz:Number = 0;
    		private var friction:Number = 0.98;
    		private var fl:Number = 250;
    		private var vpX:Number = stage.stageWidth / 2;
    		private var vpY:Number = stage.stageHeight / 2;
    		
    		public function Velocity3D() {
            init();
        }
        
        private function init():void {
        		ball = new Ball();
        		addChild( ball );
        		addEventListener(Event.ENTER_FRAME, onEnterFrame);
        		stage.addEventListener(KeyboardEvent.KEY_DOWN, onKeyDown);
        }
        
        private function onEnterFrame(e:Event):void {
        		xpos += vx;
        		ypos += vy;
        		zpos += vz;
        		
        		vx *= friction;
        		vy *= friction;
        		vz *= friction;
        		
        		if( zpos > -fl ){
        			var scale:Number = fl / ( fl + zpos );
        			ball.scaleX = ball.scaleY = scale;
        			ball.x = vpX + xpos * scale;
        			ball.y = vpY + ypos * scale;
        			ball.visible = true;
        		} else {
        			ball.visible = false;
        		}
        }
        
        private function onKeyDown(e:KeyboardEvent):void {
        		switch ( e.keyCode ) {
        			case Keyboard.UP:
        				vy -= 1;
        				break;
        				
        			case Keyboard.DOWN:
        				vy += 1;
        				break;
        				
        			case Keyboard.LEFT:
        				vx -= 1;
        				break;
        				
        			case Keyboard.RIGHT:
        				vx += 1;
        				break;
        				
        			case Keyboard.SHIFT:
        				vz += 1;
        				break;
        				
        			case Keyboard.CONTROL:
        				vz -= 1;
        				break;
        			
        			default:
        				break;
        		}
        }
    }
}

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 var vz: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();
	}
}