Flex/WaveFormFM - Sample is best!

開発環境	Apache Flex SDK 4.12.1
	FlashDevelop 4.6.2.5
実行環境	Microsoft Windows 8.1 (64bit)
プロジェクトの種類	ActionScript 3/AS3 Project
プロジェクト名	WaveFormFM

http://www.maroon.dti.ne.jp/lance/flash/waveformfm.html

Main.as

package 
{
    import flash.display.Graphics;
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.events.MouseEvent;
    import flash.events.SampleDataEvent;
    import flash.media.Sound;
    import flash.media.SoundChannel;
    import flash.media.SoundTransform;
    import flash.text.Font;
    import flash.text.TextField;
    import flash.text.TextFieldAutoSize;
    import flash.text.TextFormat;
    import mx.utils.StringUtil;
 
    public class Main extends Sprite 
    {
        private const PI2:Number = Math.PI * 2;
        private const SR:int = 44100; // sampling rate
        private const WIDTH:int = 500;
        private const HEIGHT:int = 50;
        private const C:int = 220; // キャリア周波数
        private const M:int = 440; // モジュレータ周波数
 
        private var beta:Number;
        private var sound:Sound = new Sound;
        private var soundChannel:SoundChannel = null;
 
        public function Main():void 
        {
            if (stage) init();
            else addEventListener(Event.ADDED_TO_STAGE, init);
        }
 
        private function init(e:Event = null):void 
        {
            removeEventListener(Event.ADDED_TO_STAGE, init);
            // entry point
 
            var textFormat:TextFormat = new TextFormat(null, 20);
 
            var tf:TextField = new TextField;
            tf.x = 10;
            tf.y = 10;
            tf.autoSize = TextFieldAutoSize.LEFT;
            tf.border = true;
            tf.defaultTextFormat = textFormat;
            tf.text = StringUtil.substitute("C = {0}Hz, M = {1}Hz", C, M);
            addChild(tf);
 
            //
            const betalist:Array = [ 0.1, 1, 10, 100 ]; // 変調指数
 
            for (var r:int = 0; r < betalist.length; r++) 
            {
                tf = new TextField;
                tf.x = 10;
                tf.y = 50 + (HEIGHT * 2 + 10) * r;
                tf.width = 100;
                tf.height = HEIGHT * 2;
                tf.border = true;
                tf.defaultTextFormat = textFormat;
                tf.text = "β=" + betalist[r];
                addChild(tf);
 
                var sp:Sprite = new Sprite;
                sp.name = betalist[r];
                sp.x = 120;
                sp.y = tf.y;
                sp.addEventListener(MouseEvent.MOUSE_DOWN, onMouseDown);
                sp.addEventListener(MouseEvent.MOUSE_UP, onMouseUp);
                addChild(sp);
 
                var g:Graphics = sp.graphics;
                g.clear();
                g.beginFill(0xeeeeee);
                g.drawRect(0, 0, WIDTH, HEIGHT * 2);
                g.endFill();
                g.lineStyle(1);
                g.moveTo(WIDTH, HEIGHT);
                g.lineTo(0, HEIGHT);
                g.lineStyle(1, 0xff0000);
                var wf:Array = generate(betalist[r]);
                for (var i:int = 0; i < WIDTH; i++) 
                {
                    g.lineTo(i, HEIGHT - HEIGHT * wf[i]);
                }
            }
 
            sound.addEventListener(SampleDataEvent.SAMPLE_DATA, onSampleData);
        }
 
        private function generate(b:Number):Array 
        {
            var wf:Array = new Array(WIDTH);
            for (var i:int = 0; i < WIDTH; i++) 
            {
                var t:Number = i / SR;
                wf[i] = Math.sin(PI2 * C * t + b * Math.sin(PI2 * M * t));
            }
            return wf;
        }
 
        private function onSampleData(e:SampleDataEvent):void 
        {
            for (var i:int = 0; i < 8192; i++) 
            {
                var t:Number = (e.position + i) / SR;
                var value:Number = Math.sin(PI2 * C * t + beta * Math.sin(PI2 * M * t));
                e.data.writeFloat(value);
                e.data.writeFloat(value);
            }
        }
 
        private function onMouseDown(e:MouseEvent):void 
        {
            beta = parseFloat(e.target.name);
 
            var st:SoundTransform = new SoundTransform;
            st.volume = 0.2;
            soundChannel = sound.play(0, 0, st);
        }
 
        private function onMouseUp(e:MouseEvent):void 
        {
            if (soundChannel != null)
            {
                soundChannel.stop();
                soundChannel = null;
            }
        }
 
    }
 
}