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社区首页 >专栏 >as3绘制抛物线(二)

as3绘制抛物线(二)

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meteoric
发布2018-11-16 17:19:53
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发布2018-11-16 17:19:53
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文章被收录于专栏:游戏杂谈

上一篇文章,只是简单的求出了抛物线的坐标,而且也不够灵活。如果只是单纯的画线,使用as3自带的curveTo(二次贝塞尔曲线)就已经足够了。

二次贝塞尔曲线演示动画 t in [0, 1]  (图片来源于wiki贝塞尔曲线>>)

下面的例子,根据鼠标的位置,绘制经过指定起始点、结束点和鼠标位置的曲线。

Code:

代码语言:javascript
复制
1: package  

       2: {

       3:     import flash.display.Sprite;

       4:     import flash.events.Event;

       5:     

       6:     /**

       7:      * ...

       8:      * @author Meteoric

       9:      */

      10:     public class DrawCurveDemo extends Sprite

      11:     {

      12:         private var x0:Number = 100;

      13:         private var y0:Number = 400;

      14:         private var x1:Number;

      15:         private var y1:Number;

      16:         private var x2:Number = 500;

      17:         private var y2:Number = 400;

      18:         

      19:         public function DrawCurveDemo() 

      20:         {

      21:             initView();

      22:         }

      23:         

      24:         private function initView():void

      25:         {

      26:             addEventListener(Event.ENTER_FRAME, onEnterFrameHandler);

      27:             

      28:             onEnterFrameHandler();

      29:         }

      30:         

      31:         private function onEnterFrameHandler(e:Event=null):void 

      32:         {

      33:             x1 = mouseX;

      34:             y1 = mouseY;

      35:             

      36:             graphics.clear();

      37:             graphics.lineStyle(2, 0x3399cc);

      38:             graphics.moveTo(x0, y0);

      39:             graphics.curveTo(x1, y1, x2, y2);

      40:         }

      41:         

      42:     }

      43:  

      44: }

上面仅仅支持线条的绘制,如果是一个影片剪辑想要移动,则会比较麻烦。好在AS3的类库TweenMax已经完全支持了。

image
image

参考文档说明,实现如下的示例效果:

先定义一个名为Arrow.as,它用于在舞台上画一个红色的“箭头”

代码语言:javascript
复制
1: package  

       2: {

       3:     import flash.display.Sprite;

       4:     

       5:     /**

       6:      * ...

       7:      * @author Meteoric

       8:      */

       9:     public class Arrow extends Sprite

      10:     {

      11:         

      12:         public function Arrow() 

      13:         {

      14:             initView();

      15:         }

      16:         

      17:         private function initView():void

      18:         {

      19:             graphics.clear();

      20:             graphics.lineStyle(1, 0xff0000);

      21:             graphics.moveTo(-100, -5);

      22:             graphics.lineTo(-20, -5);

      23:             graphics.lineTo(-20, -20);

      24:             graphics.lineTo(0, 0);

      25:             graphics.lineTo(-20, 20);

      26:             graphics.lineTo(-20, 5);

      27:             graphics.lineTo(-100, 5);

      28:             graphics.lineTo(-100, -5);

      29:         }

      30:         

      31:     }

      32:  

      33: }

然后定义一个ArrowTest.as用于测试效果:

代码语言:javascript
复制
1: package  

       2: {

       3:     import flash.display.Sprite;

       4:     import flash.utils.setTimeout;

       5:     import gs.TweenMax;

       6:     /**

       7:      * ...

       8:      * @author Meteoric

       9:      */

      10:     public class ArrowTest extends Sprite

      11:     {

      12:         

      13:         public function ArrowTest() 

      14:         {

      15:             initView();

      16:         }

      17:         

      18:         private var arrow:Arrow;

      19:         

      20:         private function initView():void

      21:         {

      22:             if (arrow == null)

      23:             {

      24:                 arrow = new Arrow();

      25:                 addChild(arrow);

      26:             }

      27:             arrow.x = 100;

      28:             arrow.y = 300;

      29:             

      30:             graphics.clear();

      31:             graphics.lineStyle(1, 0x000000);

      32:             graphics.moveTo(arrow.x, arrow.y);

      33:             

      34:             TweenMax.to(arrow, 3, {x:600, y:400, bezierThrough:[{x:300, y:100}], orientToBezier:true, onUpdate:onUpdateHandler, onComplete:onCompleteHandler});

      35:         }

      36:         

      37:         private function onUpdateHandler():void

      38:         {

      39:             graphics.lineTo(arrow.x, arrow.y);

      40:         }

      41:         

      42:         private function onCompleteHandler():void

      43:         {

      44:             setTimeout(initView, 2 * 1000);

      45:         }

      46:         

      47:     }

      48:  

      49: }
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原始发表:2012-04-17 ,如有侵权请联系 cloudcommunity@tencent.com 删除

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