Source for the whole thing is in Google Code here – it currently converts everything from stereo->mono, but I’ll be working on getting it all working in stereo soon!

To try out the game so far, head here, press 1 to start the game, and use A and D for left/right, W for jump, and space for sonar (requires Flash 10!).

AudioEngine is probably the key class to look at, as it handles the various oscillators and filter stacks. All sound is created prior to the game beginning at present, but the classes should still be useful for realtime effects!

For this to work, there are a couple of functions. First, one that generates the sound – a sine wave here:

public function generateSound():ByteArray
{
	var sound:ByteArray = new ByteArray();

	for(var i:int=0; i<16000; i++)
	{
		var sample:Number = Math.sin((Number(i)/Math.PI/2))*0.25;
		sound.writeFloat(sample);
		sound.writeFloat(sample);
	}

	return sound;
}

Then a segment in the game entity to prepare and play the sound, given the ByteArray as soundData:

var sound:Sound = new Sound();
sound.addEventListener(SampleDataEvent.SAMPLE_DATA, this.handleSampleData);
this.soundData.position = 0;
this.soundChannel = sound.play();

And finally, a SAMPLE_DATA listener to play back the sample:

private function handleSampleData(event : SampleDataEvent) : void
{
	for(var i:int=0; i<4096*2; i++)
	{
		if(this.soundData.bytesAvailable)
		{
			event.data.writeFloat(this.soundData.readFloat());
		}
	}
}

This provides 4096 samples per channel – 8192 in stereo, which is the maximum we can provide. Once the end of the data is reached and the number of samples goes below 512, the sound will stop automatically.

• 1: Trigger alarm
• 2, 3, 4: Trigger ceiling lights
• a, d: Move left and right (note that there’s no collision detection, gravity, etc, in here yet)
• space: Fire off sonar burst.

Obviously the final game will look very different, and not have such huge sounds

Click here to launch

var a:Number = 1/2 // 566 bytes
vs
var a:Number = 1*0.5 // 570 bytes


// 585 bytes
var b:Number = 1*0.5*2;
var c:Number = 1*0.5*3;
var d:Number = 1*0.5*4;
vs
// 589 bytes
var a:Number = 1*0.5;
var b:Number = a*2;
var c:Number = a*3;
var d:Number = a*4;



for(var i:int=0; i<10; i++) // 578 bytes
vs
for(var i:uint=0; i<10; i++) // 582 bytes