AS3控制音樂的音量及聲道

鼠標在場景中控制音樂的音量、聲道。
往上，音量增加。往下，音量降低。
往左，左聲道，往右，右聲道。

代碼：

package {
import flash.display.Sprite;
import flash.display.StageAlign;
import flash.display.StageScaleMode;
import flash.events.*;
import flash.media.Sound;
import flash.media.SoundChannel;
import flash.media.SoundTransform;
import flash.net.URLRequest;
import flash.utils.Timer;
public class SoundTransformExample extends Sprite {
private var url:String = "2009515175350546.mp3";
private var soundFactory:Sound;
private var channel:SoundChannel;
private var positionTimer:Timer;
public function SoundTransformExample() {
stage.align = StageAlign.TOP_LEFT;
stage.scaleMode = StageScaleMode.NO_SCALE;
var request:URLRequest = new URLRequest(url);
soundFactory = new Sound();
soundFactory.addEventListener(IOErrorEvent.IO_ERROR, ioErrorHandler);
soundFactory.load(request);
channel = soundFactory.play();
stage.addEventListener(MouseEvent.MOUSE_MOVE, mouseMoveHandler);
}
private function ioErrorHandler(event:Event):void {
trace("ioErrorHandler: " + event);
}
private function setPan(pan:Number):void {
trace("setPan: " + pan.toFixed(2));
var transform:SoundTransform = channel.soundTransform;
transform.pan = pan;
channel.soundTransform = transform;
}
private function setVolume(volume:Number):void {
trace("setVolume: " + volume.toFixed(2));
var transform:SoundTransform = channel.soundTransform;
transform.volume = volume;
channel.soundTransform = transform;
}
private function mouseMoveHandler(event:MouseEvent):void {
var halfStage:uint = Math.floor(stage.stageWidth / 2);
var xPos:uint = event.stageX;
var yPos:uint = event.stageY;
var value:Number;
var pan:Number;
if (xPos > halfStage) {
value = xPos / halfStage;
pan = value - 1;
} else if (xPos < halfStage) {
value = (xPos - halfStage) / halfStage;
pan = value;
} else {
pan = 0;
}
var volume:Number = 1 - (yPos / stage.stageHeight);
setVolume(volume);
setPan(pan);
}
}
}