flash AS3小记6.docVIP

flash AS3小记6 1、速度向量扩展（85/352） RotationalVelocity.as 通常将转速度变量命名为vr，表示旋转速度。速度向量值为5，方向为顺时针。同理，其他属性也可以改变。 arrow.x += vx; arrow.y += vy; arrow.rotation += vr; arrow.alpha += vAlpha; arrow.scaleX = arrow.scaleY += vScale; //ActionScript package { import flash.display.Sprite; import flash.events.Event; /** * ... * @author 冯润娜 */ public class RotationalVelocity extends Sprite { private var arrow:Arrow; private var vr:Number = 5; public function RotationalVelocity () { init (); } private function init ():void { arrow = new Arrow(); addChild (arrow); arrow.x = stage.stageWidth / 2; arrow.y = stage.stageHeight / 2; addEventListener (Event.ENTER_FRAME,onEnterFrame); } private function onEnterFrame (event:Event):void { arrow.rotation += vr; } } } 2、加速度（87/352) Accelerationl.as // ActionScript file单轴加速度 开始速度向量（vx)为零，加速度（ax）为0.2，每一帧加速度都被加入到速度向量中，再加到小球的位置上。 package { import flash.display.Sprite; import flash.events.Event; /** * ... * @author 冯润娜 */ public class Accelerationl extends Sprite { private var vx:Number = 0; private var ax:Number = 0.2; private var ball:Ball; public function Accelerationl () { init (); } private function init ():void { ball = new Ball ; addChild (ball); ball.x = 50; ball.y = 100; addEventListener (Event.ENTER_FRAME,onEnterFrame); } private function onEnterFrame (e:Event):void { vx += ax; ball.x+=vx; } } } Acceleration2.as（87/352） 该例允许小球拥有加速度和反加速度。用Keyboard.LEFT和Keyboard.RIGHT来改变加速度 // ActionScript file 左右加速度 package { import flash.display.Sprite; import flash.events.Event; import flash.events.KeyboardEvent; import flash.ui.Keyboard; /** * ... * @author 冯润娜 */ public class Acceleration2 extends Sprite { private var ball:Ball; private var vx:Number = 0; private var ax:Number = 0; public function Acceleration2 () { init (); } private function init ():void { ball = new Ball ; add