doing this

1 files changed, 125 insertions, 0 deletions

diff --git a/audio.js b/audio.js
new file mode 100644
index 0000000..2e21cda
--- /dev/null
+++ b/audio.js
@@ -0,0 +1,125 @@
+var sampleRate = 44100; /* hard-coded in Flash player */
+
+function AudioPlayer(generator, opts) {
+	if (!opts) opts = {};
+	var latency = opts.latency || 1;
+	var checkInterval = latency * 100 /* in ms */
+	
+	var audioElement = new Audio();
+	var webkitAudio = window.AudioContext || window.webkitAudioContext;
+	var requestStop = false;
+	
+	if (audioElement.mozSetup) {
+		audioElement.mozSetup(2, sampleRate); /* channels, sample rate */
+		
+		var buffer = []; /* data generated but not yet written */
+		var minBufferLength = latency * 2 * sampleRate; /* refill buffer when there are only this many elements remaining */
+		var bufferFillLength = Math.floor(latency * sampleRate);
+		
+		function checkBuffer() {
+			if (buffer.length) {
+				var written = audioElement.mozWriteAudio(buffer);
+				buffer = buffer.slice(written);
+			}
+			if (buffer.length < minBufferLength && !generator.finished) {
+				buffer = buffer.concat(generator.generate(bufferFillLength));
+			}
+			if (!requestStop && (!generator.finished || buffer.length)) {
+				setTimeout(checkBuffer, checkInterval);
+			}
+		}
+		checkBuffer();
+		
+		return {
+			'type': 'Firefox Audio',
+			'stop': function() {
+				requestStop = true;
+			}
+		}
+	} else if (webkitAudio) {
+		// Uses Webkit Web Audio API if available
+		var context = new webkitAudio();
+		sampleRate = context.sampleRate;
+		
+		var channelCount = 2;
+		var bufferSize = 4096*4; // Higher for less gitches, lower for less latency
+		
+		var node = context.createScriptProcessor(bufferSize, 0, channelCount);
+		
+		node.onaudioprocess = function(e) { process(e) };
+
+		function process(e) {
+			if (generator.finished) {
+				node.disconnect();
+				return;
+			}
+			
+			var dataLeft = e.outputBuffer.getChannelData(0);
+			var dataRight = e.outputBuffer.getChannelData(1);
+
+			var generate = generator.generate(bufferSize);
+
+			for (var i = 0; i < bufferSize; ++i) {
+				dataLeft[i] = generate[i*2];
+				dataRight[i] = generate[i*2+1];
+			}
+		}
+		
+		// start
+		node.connect(context.destination);
+		
+		return {
+			'stop': function() {
+				// pause
+				node.disconnect();
+				requestStop = true;
+			},
+			'type': 'Webkit Audio'
+		}
+
+	} else {
+		// Fall back to creating flash player
+		var c = document.createElement('div');
+		c.innerHTML = '<embed type="application/x-shockwave-flash" id="da-swf" src="da.swf" width="8" height="8" allowScriptAccess="always" style="position: fixed; left:-10px;" />';
+		document.body.appendChild(c);
+		var swf = document.getElementById('da-swf');
+		
+		var minBufferDuration = latency * 1000; /* refill buffer when there are only this many ms remaining */
+		var bufferFillLength = latency * sampleRate;
+		
+		function write(data) {
+			var out = new Array(data.length);
+			for (var i = data.length-1; i != 0; i--) {
+				out[i] = Math.floor(data[i]*32768);
+			}
+			return swf.write(out.join(' '));
+		}
+		
+		function checkBuffer() {
+			if (swf.bufferedDuration() < minBufferDuration) {
+				write(generator.generate(bufferFillLength));
+			};
+			if (!requestStop && !generator.finished) setTimeout(checkBuffer, checkInterval);
+		}
+		
+		function checkReady() {
+			if (swf.write) {
+				checkBuffer();
+			} else {
+				setTimeout(checkReady, 10);
+			}
+		}
+		checkReady();
+		
+		return {
+			'stop': function() {
+				swf.stop();
+				requestStop = true;
+			},
+			'bufferedDuration': function() {
+				return swf.bufferedDuration();
+			},
+			'type': 'Flash Audio'
+		}
+	}
+}