Soundを動的に生成, computeSpectrum使って出力

by cpu_t 05 Jan 2010

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/**
 * Copyright cpu_t ( http://wonderfl.net/user/cpu_t )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/v76j
 */

package {
	import flash.display.Bitmap;
	import flash.display.BitmapData;
	import flash.display.Shape;
    import flash.display.Sprite;
	import flash.events.Event;
	import flash.events.MouseEvent;
	import flash.events.SampleDataEvent;
	import flash.geom.Matrix;
	import flash.geom.Rectangle;
	import flash.media.Sound;
	import flash.media.SoundChannel;
	import flash.media.SoundMixer;
	import flash.utils.ByteArray;
	
	[SWF(frameRate="30", width="512", height="300")]
    public class BitmapToSound extends Sprite {
		private var _playingSound:Sound;
		private var _soundChannel:SoundChannel;
		
		private var _isPlay:Boolean = false;
		
		private var _soundWaveShape:Shape;
		
        public function BitmapToSound() {
			stage.addEventListener(MouseEvent.MOUSE_DOWN,
			function(e:MouseEvent):void
			{
				if (_isPlay) _soundChannel.stop();
				else _soundChannel = _playingSound.play();
				_isPlay = !_isPlay;
			});
			addEventListener(Event.ENTER_FRAME, enterFrameHandler);
			
            _playingSound = new Sound();
			_playingSound.addEventListener(SampleDataEvent.SAMPLE_DATA, soundWaveGenerator);
			_soundChannel = _playingSound.play();
			_isPlay = true;
			
			_soundWaveShape = new Shape();
			addChild(_soundWaveShape);
        }
		
		private function enterFrameHandler(e:Event):void
		{
			if (_isPlay) drawSoundWave();
		}
		
		private function soundWaveGenerator(event:SampleDataEvent):void
		{
			var v:Number;
			for (var c:int = 0; c < 8192; c++) {
				v = Math.sin((Number(c + event.position) / Math.PI / 2));
				v = v * 0.25;
				event.data.writeFloat(v); // 左チャンネルに書き込み
				event.data.writeFloat(v); // 右チャンネルに書き込み
			}
		}
		
		private function drawSoundWave():void
		{
			var i:int, n:Number;
			var bytes:ByteArray = new ByteArray();
			const PLOT_HEIGHT:int = 100;
			const CHANNEL_LENGTH:int = 256;
			
			SoundMixer.computeSpectrum(bytes, false, 0);
			
			_soundWaveShape.graphics.clear();
			_soundWaveShape.graphics.beginFill(0x404040);
			_soundWaveShape.graphics.drawRect(0, 0, 512, 300);
			_soundWaveShape.graphics.endFill();
			
			// 左チャンネル出力
			_soundWaveShape.graphics.lineStyle(1, 0x00FF00);
			_soundWaveShape.graphics.beginFill(0x00FF00, 0.5);
			_soundWaveShape.graphics.moveTo(0, PLOT_HEIGHT);
			for (i = 0; i < CHANNEL_LENGTH; i++) {
				n = bytes.readFloat();
				n = n * PLOT_HEIGHT;
				_soundWaveShape.graphics.lineTo(i * 2, PLOT_HEIGHT - n);
			}
			_soundWaveShape.graphics.lineTo(CHANNEL_LENGTH * 2, PLOT_HEIGHT);
			_soundWaveShape.graphics.endFill();
			
			// 右チャンネル出力
			_soundWaveShape.graphics.lineStyle(1, 0x00FFFF);
			_soundWaveShape.graphics.beginFill(0x00FFFF, 0.5);
			_soundWaveShape.graphics.moveTo(0, PLOT_HEIGHT * 2);
			for (i = 0; i < CHANNEL_LENGTH; i++) {
				n = bytes.readFloat();
				n = n * PLOT_HEIGHT;
				_soundWaveShape.graphics.lineTo(i * 2, PLOT_HEIGHT * 2 - n);
			}
			_soundWaveShape.graphics.lineTo(CHANNEL_LENGTH * 2, PLOT_HEIGHT * 2);
			_soundWaveShape.graphics.endFill();
		}
    }
}