From 08c3a63dc170c5f3154a86566e7b31b133d20cda Mon Sep 17 00:00:00 2001
From: alfred <alfred@klandestino.se>
Date: Wed, 1 Jan 2014 00:27:03 +0000
Subject: [PATCH] average mixing

---
 lib/mixer.js | 40 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 37 insertions(+), 3 deletions(-)

diff --git a/lib/mixer.js b/lib/mixer.js
index 497f02f..85dbc8e 100644
--- a/lib/mixer.js
+++ b/lib/mixer.js
@@ -9,11 +9,27 @@ function Mixer(args) {
 
 	if (typeof args === 'undefined') args = {};
 	if (args.channels != 1 && args.channels != 2) args.channels = 2;
-	if (args.bitDepth != 8 && args.bitDepth != 16 && args.bitDepth != 32) args.bitDepth = 16;
 	if (typeof args.sampleRate === 'number' || args.sampleRate < 1) args.sampleRate = 44100; 
 
-	this.channels = args.channels;
 	this.bitDepth = args.bitDepth;
+	if (args.bitDepth == 8) {
+		this.readSample = Buffer.readInt8;
+		this.writeSample = Buffer.writeInt8;
+		this.sampleByteLength = 1;
+	}
+	else if (args.bitDepth == 32) {
+		this.readSample = Buffer.readInt32LE;
+		this.writeSample = Buffer.writeInt32LE;
+		this.sampleByteLength = 4;
+	}
+	else {
+		args.bitDepth = 16;
+		this.readSample = Buffer.readInt16LE;
+		this.writeSample = Buffer.writeInt16LE;
+		this.sampleByteLength = 2;
+	}
+
+	this.channels = args.channels;
 	this.sampleRate = args.sampleRate;
 
 	this.inputs = [];
@@ -22,7 +38,25 @@ function Mixer(args) {
 util.inherits(Mixer, Readable);
 
 Mixer.prototype._read = function() {
-	this.push(0);
+
+	var samples = 9007199254740992;
+	this.inputs.forEach(function (input) {
+		var as = input.availSamples();
+		if (as < samples) samples = as;
+	});
+	if (samples > 0) {
+
+		var mixedBuffer = new Buffer(samples * this.sampleByteLength);
+		for (var i = 0; i < samples; i++) {
+			var mixedSample = 0;
+			for (var j = 0; j < this.inputs.length; j++) {
+				mixedSample += this.inputs[j].readSample.call(this.inputs[j], i * this.inputs[j].sampleByteLength);
+			}
+			this.writeSample.call(mixedBuffer, Math.round(mixedSample / this.inputs.length), i * this.sampleByteLength);
+		}
+
+		this.push(mixedBuffer);
+	}
 }
 
 Mixer.prototype.input = function (args) {