Split library in parts

CHANGELOG.md

@@ -1,3 +1,6 @@
+[0.6.0]
+- Split functionallity in files
+
 [0.5.0]
 - Duration no longer required (thanks @benwiley4000).
 

INSTRUMENTS.md

@@ -2,6 +2,7 @@
 
 If you need to copy and paste... ;-)
 
+```
 accordion
 acoustic_bass
 acoustic_grand_piano
@@ -130,3 +131,4 @@ voice_oohs
 whistle
 woodblock
 xylophone
+```

README.md

@@ -145,7 +145,7 @@ To run pure javascript examples `npm install -g beefy` then `beefy examples/pian
 
 ## Available instruments
 
-You can grab a [json file](https://github.com/danigb/soundfont-player/blob/master/instruments.json) with all the instruments, or require it:
+You can grab a [json file](https://github.com/danigb/soundfont-player/blob/master/instruments.json) with all the instrument names, or require it:
 
 ```js
 var instrumentNames = require('soundfont-player/instruments.json');

examples/oscillator.js

@@ -0,0 +1,11 @@
+
+var ctx = new window.AudioContext()
+var soundfont = require('..')(ctx)
+
+var osc = soundfont.instrument()
+osc.onready(function () {
+  var time = ctx.currentTime
+  'G3 B3 D4'.split(' ').forEach(function (note, index) {
+    osc.play(note, time + index)
+  })
+})

examples/piano.js

@@ -3,9 +3,12 @@ var ctx = new window.AudioContext()
 var soundfont = require('..')(ctx)
 
 var piano = soundfont.instrument('acoustic_grand_piano')
-piano.onready(function () {
+play('A4 C#5 E5')
+piano.onready(function () { play('E5 C#5 A4') })
+
+function play (notes) {
   var time = ctx.currentTime
-  'A4 C#5 E5'.split(' ').forEach(function (note, index) {
+  notes.split(' ').forEach(function (note, index) {
     piano.play(note, time + index)
   })
-})
+}

lib/buffers-player.js

@@ -0,0 +1,16 @@
+'use strict'
+
+var midi = require('note.midi')
+
+module.exports = function (ctx, buffers, options) {
+  return function (note, time, duration) {
+    var buffer = buffers[midi(note)]
+    if (!buffer) return
+    var source = ctx.createBufferSource()
+    source.buffer = buffer
+    source.connect(ctx.destination)
+    source.start(time)
+    if (duration > 0) source.stop(time + duration)
+    return source
+  }
+}

lib/index.js

@@ -0,0 +1,53 @@
+'use strict'
+
+var loadBank = require('./load-bank')
+var oscillatorPlayer = require('./oscillator-player')
+var buffersPlayer = require('./buffers-player')
+
+module.exports = Soundfont
+
+/**
+ * Create a Soundfont object
+ *
+ * @param {AudioContext} context - the [audio context](https://developer.mozilla.org/en/docs/Web/API/AudioContext)
+ * @return {Soundfont} a soundfont object
+ */
+function Soundfont (ctx, nameToUrl) {
+  if (!(this instanceof Soundfont)) return new Soundfont(ctx)
+
+  this.nameToUrl = nameToUrl || Soundfont.nameToUrl || gleitzUrl
+  this.ctx = ctx
+  this.instruments = {}
+  this.promises = []
+}
+
+Soundfont.prototype.instrument = function (name, options) {
+  var ctx = this.ctx
+  name = name || 'default'
+  if (name in this.instruments) return this.instruments[name]
+  var inst = { name: name, play: oscillatorPlayer(ctx, options) }
+  this.instruments[name] = inst
+  var promise = loadBank(ctx, this.nameToUrl(name))
+  this.promises.push(promise)
+  promise.then(function (buffers) {
+    inst.play = buffersPlayer(ctx, buffers, options)
+  })
+  inst.onready = function (cb) { promise.then(cb) }
+  return inst
+}
+
+Soundfont.loadBuffers = function (ctx, name) {
+  var nameToUrl = Soundfont.nameToUrl || gleitzUrl
+  return loadBank(ctx, nameToUrl(name))
+}
+
+/*
+ * Given an instrument name returns a URL to to the Benjamin Gleitzman's
+ * package of [pre-rendered sound fonts](https://github.com/gleitz/midi-js-soundfonts)
+ *
+ * @param {String} name - instrument name
+ * @returns {String} the Soundfont file url
+ */
+function gleitzUrl (name) {
+  return 'https://cdn.rawgit.com/gleitz/midi-js-Soundfonts/master/FluidR3_GM/' + name + '-ogg.js'
+}

lib/load-bank.js

@@ -0,0 +1,76 @@
+'use strict'
+
+var midi = require('note.midi')
+var decodeBuffer = require('./decode-buffer')
+
+/**
+ * Load a soundfont bank
+ *
+ * @param {AudioContext} ctx - the audio context object
+ * @param {String} url - the url of the js file
+ * @param {Function} get - (Optional) given a url return a promise with the contents
+ * @param {Function} parse - (Optinal) given a js file return JSON object
+ */
+module.exports = function (ctx, url, get, parse) {
+  get = get || getContent
+  parse = parse || parseJavascript
+  return Promise.resolve(url).then(get).then(parse)
+    .then(function (data) {
+      return { ctx: ctx, data: data, buffers: {} }
+    })
+    .then(decodeBank)
+    .then(function (bank) { return bank.buffers })
+}
+
+function getContent (url) {
+  return new Promise(function (done, reject) {
+    var req = new window.XMLHttpRequest()
+    req.open('GET', url)
+
+    req.onload = function () {
+      if (req.status === 200) {
+        done(req.response)
+      } else {
+        reject(Error(req.statusText))
+      }
+    }
+    req.onerror = function () {
+      reject(Error('Network Error'))
+    }
+    req.send()
+  })
+}
+
+/**
+ *  Parse the SoundFont data and return a JSON object
+ *  (SoundFont data are .js files wrapping json data)
+ *
+ * @param {String} data - the SoundFont js file content
+ * @return {JSON} the parsed data as JSON object
+ * @api private
+ */
+function parseJavascript (data) {
+  var begin = data.indexOf('MIDI.Soundfont.')
+  begin = data.indexOf('=', begin) + 2
+  var end = data.lastIndexOf(',')
+  return JSON.parse(data.slice(begin, end) + '}')
+}
+
+/*
+ * Decode a bank
+ * @param {Object} bank - the bank object
+ * @return {Promise} a promise that resolves to the bank with the buffers decoded
+ * @api private
+ */
+function decodeBank (bank) {
+  var promises = Object.keys(bank.data).map(function (note) {
+    return decodeBuffer(bank.ctx, bank.data[note])
+    .then(function (buffer) {
+      bank.buffers[midi(note)] = buffer
+    })
+  })
+
+  return Promise.all(promises).then(function () {
+    return bank
+  })
+}

lib/oscillator-player.js

@@ -0,0 +1,36 @@
+'use strict'
+
+var freq = require('midi.freq')(440)
+var midi = require('note.midi')
+
+/**
+ * Returns a function that plays an oscillator
+ *
+ */
+module.exports = function (context, options) {
+  return function (note, time, duration) {
+    var f = freq(midi(note))
+    if (!f) return
+
+    options = options || {}
+    duration = duration || 0.2
+
+    var vcoType = options.vcoType || 'sine'
+
+    var vco = context.createOscillator()
+    vco.type = vcoType
+    vco.frequency.value = f
+
+    /* VCA */
+    var vca = context.createGain()
+    vca.gain.value = options.gain || 0.5
+
+    /* Connections */
+    vco.connect(vca)
+    vca.connect(context.destination)
+
+    vco.start(time)
+    if (duration > 0) vco.stop(time + duration)
+    return vco
+  }
+}

package.json

@@ -1,8 +1,8 @@
 {
   "name": "soundfont-player",
-  "version": "0.5.0",
+  "version": "0.6.0",
   "description": "Lightweight soundfont (music instrument) loader and player for WebAudio API",
-  "main": "index.js",
+  "main": "lib/index.js",
   "scripts": {
     "test": "vows test/*.js",
     "dist": "browserify index.js > dist/soundfont-player.js && uglifyjs dist/soundfont-player.js > dist/soundfont-player.min.js"
@@ -25,7 +25,8 @@
     "url": "https://github.com/danigb/soundfont-player/issues"
   },
   "dependencies": {
-    "note-parser": "^0.7.0"
+    "midi.freq": "^1.0.0",
+    "note.midi": "0.0.3"
   },
   "devDependencies": {
     "vows": "^0.8.1"

test/load-buffers.js

@@ -3,22 +3,22 @@ var vows = require('vows')
 var assert = require('assert')
 var fs = require('fs')
 
-var Soundfont = require('../')
+var loadBank = require('../lib/load-bank')
 
 // Mocks
 var audioContext = {}
 audioContext.decodeAudioData = function (data, callback) { callback(data) }
 
-Soundfont.nameToUrl = function (name) { return './test/support/' + name + '.js' }
-Soundfont.loadData = function (url) {
+function nameToUrl (name) { return './test/support/' + name + '.js' }
+function load (url) {
   var src = fs.readFileSync(url, 'utf8')
   return Promise.resolve(src)
 }
 
 vows.describe('Soundfont.loadBuffers').addBatch({
   'loading a buffer': {
     'topic': function () {
-      Soundfont.loadBuffers(audioContext, 'piano').then(this.callback)
+      loadBank(audioContext, nameToUrl('piano'), load).then(this.callback)
     },
     'load buffers': function (buffers, nothing) {
       assert.deepEqual(buffers, { 21: {}, 22: {}, 23: {}, 24: {}, 25: {} })