flash on 2011-5-18

by omr 18 May 2011

Tags

基本 物理
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/**
 * Copyright omr ( http://wonderfl.net/user/omr )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/i3Rh
 */

package {
    import flash.display.Sprite;
    import flash.display.StageAlign;
    import flash.display.StageScaleMode;
    import flash.events.Event;
    import flash.events.MouseEvent;
    
    public class Throwing extends Sprite {
        private var ball:Ball;
        private var vx:Number;
        private var vy:Number;
        private var bounce:Number = -0.7;
        private var gravity:Number = .5;
        private var oldX:Number;
        private var oldY:Number;
        
        public function Throwing() {
            init();
        }
        
        private function init():void {
            stage.scaleMode = StageScaleMode.NO_SCALE;
            stage.align=StageAlign.TOP_LEFT;

            ball = new Ball();
            ball.x = stage.stageWidth / 2;
            ball.y = stage.stageHeight / 2;
            vx = Math.random() * 10 - 5;
            vy = -10;
            addChild(ball);
            ball.addEventListener(MouseEvent.MOUSE_DOWN, onMouseDown);
            addEventListener(Event.ENTER_FRAME, onEnterFrame);
        }
        
        private function onEnterFrame(event:Event):void {
            vy += gravity;
            ball.x += vx;
            ball.y += vy;
            var left:Number = 0;
            var right:Number = stage.stageWidth;
            var top:Number = 0;
            var bottom:Number = stage.stageHeight;
            
            if(ball.x + ball.radius > right) {
                ball.x = right - ball.radius;
                vx *= bounce;
            } else if(ball.x - ball.radius < left) {
                ball.x = left + ball.radius;
                vx *= bounce;
            }
            if(ball.y + ball.radius > bottom) {
                ball.y = bottom - ball.radius;
                vy *= bounce;
            } else if(ball.y - ball.radius < top) {
                ball.y = top + ball.radius;
                vy *= bounce;
            }
        }
        
        private function onMouseDown(event:MouseEvent):void {
            oldX = ball.x;
            oldY = ball.y;
            stage.addEventListener(MouseEvent.MOUSE_UP, onMouseUp);
            ball.startDrag();
            removeEventListener(Event.ENTER_FRAME, onEnterFrame);
            addEventListener(Event.ENTER_FRAME, trackVelocity);
        }
        
        private function onMouseUp(event:MouseEvent):void {
            stage.removeEventListener(MouseEvent.MOUSE_UP, onMouseUp);
            ball.stopDrag();
            removeEventListener(Event.ENTER_FRAME, trackVelocity);
            addEventListener(Event.ENTER_FRAME, onEnterFrame);
        }
        
        private function trackVelocity(event:Event):void {
            vx = ball.x - oldX;
            vy = ball.y - oldY;
            oldX = ball.x;
            oldY = ball.y;
        }
    }
}


import flash.display.Sprite;
    
class Ball extends Sprite {
     public var radius:Number;
     private 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();
     }
}