Tone.js/Tone/core/Bus.js

define(["Tone/core/Tone", "Tone/core/Gain"], function(Tone){

	"use strict";

	/**
	 *  buses are another way of routing audio
	 *
	 *  augments Tone.prototype to include send and receive
	 */

	/**
	 *  All of the routes
	 *
	 *  @type {Object}
	 *  @static
	 *  @private
	 */
	var Buses = {};

	/**
	 *  Send this signal to the channel name.
	 *  @param  {String} channelName A named channel to send the signal to.
	 *  @param  {Decibels} amount The amount of the source to send to the bus.
	 *  @return {GainNode} The gain node which connects this node to the desired channel.
	 *                     Can be used to adjust the levels of the send.
	 *  @example
	 * source.send("reverb", -12);
	 */
	Tone.prototype.send = function(channelName, amount){
		if (!Buses.hasOwnProperty(channelName)){
			Buses[channelName] = this.context.createGain();
		}
		amount = Tone.defaultArg(amount, 0);
		var sendKnob = new Tone.Gain(amount, Tone.Type.Decibels);
		this.connect(sendKnob);
		sendKnob.connect(Buses[channelName]);
		return sendKnob;
	};

	/**
	 *  Receive the input from the desired channelName to the input
	 *
	 *  @param  {String} channelName A named channel to send the signal to.
	 *  @param  {Number=} channelNumber The channel to connect to
	 *  @returns {Tone} this
	 *  @example
	 * reverbEffect.receive("reverb");
	 */
	Tone.prototype.receive = function(channelName, inputNum){
		if (!Buses.hasOwnProperty(channelName)){
			Buses[channelName] = this.context.createGain();
		}
		Buses[channelName].connect(this, 0, inputNum);
		return this;
	};

	//remove all the send/receives when a new audio context is passed in
	Tone.Context.on("init", function(context){
		if (context.buses){
			Buses = context.buses;
		} else {
			Buses = {};
			context.buses = Buses;
		}
	});

	return Tone;
});