computeSpectrum

Real-Time Flash Audio Visualizer

When Flash 9 and ActionScript3 came out, I was scrambling to learn as much as possible.  I took part in (and won) an online competition on Adobe Flash Evangelist Lee Brimelow's site The Flash Blog, to see who could make the coolest example.  It was humbling, and a great learning experience.

Here is the source for the winning entry

class Simple {
	private var s:Sound = new Sound();
	private var sc:SoundChannel = new SoundChannel();
	private var ba:ByteArray = new ByteArray();
	private var gfx:BitmapData;
	private var pic:Bitmap;
	private var ___width:uint;
	private var ___height:uint;
	private var res:Number = 7;
	private var z:Number = 0;

	function Simple(hostMC:MovieClip, mp3:String, __width:Number, __height:Number) {
		___width = __width;
		___height = __height;

		gfx =  new BitmapData(__width, __height, false, 0x000000);
		pic = new Bitmap(gfx)
		hostMC.addChild(pic);

		s.load(new URLRequest(mp3));
		sc = s.play();

		hostMC.addEventListener(Event.ENTER_FRAME, processSpectrum);
	}

	private function processSpectrum(ev:Event) {
		SoundMixer.computeSpectrum(ba,true,0);
		var num:Number = ba.readFloat();
		l = Math.pow(num,3)*___width/3;
		for (var i:int = 0; i < 1440; i++) {
			gfx.setPixel(l,i,0xffffff*Math.pow(i,2));
			for (var j:int=0;j < res; j++) {
			gfx.setPixel(Math.sin(i/360*Math.PI)*l+j*(___width/res)-50,i/j,0xffffff*Math.pow(i,2));
			}
		}
		var blur:BlurFilter = new BlurFilter(2,2);
		var displace = new DisplacementMapFilter(gfx, new Point(0, 0), 2, 1, z*l/6, z+3);
		gfx.applyFilter(gfx, new Rectangle(0, 0, ___width, ___height), new Point(0, 0), displace);
		gfx.applyFilter(gfx, new Rectangle(0, 0, ___width, ___height), new Point(0, 0), blur);
		z += 0.02;
	}
}