From 5e6e33264de460f48f7f24c57e46b11214aee412 Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Mon, 19 Jun 2017 17:25:11 -0400
Subject: [PATCH 01/14] Remove tone.js dependency

---
 src/effects/PitchEffect.js | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/effects/PitchEffect.js b/src/effects/PitchEffect.js
index 38f8fd1..f482185 100644
--- a/src/effects/PitchEffect.js
+++ b/src/effects/PitchEffect.js
@@ -1,5 +1,3 @@
-const Tone = require('tone');
-
 /**
 * A pitch change effect, which changes the playback rate of the sound in order
 * to change its pitch: reducing the playback rate lowers the pitch, increasing the rate
@@ -21,7 +19,6 @@ class PitchEffect {
     constructor () {
         this.value = 0; // effect value
         this.ratio = 1; // the playback rate ratio
-        this.tone = new Tone();
     }
 
     /**
@@ -52,9 +49,19 @@ class PitchEffect {
     * @returns {number} a playback ratio
     */
     getRatio (val) {
-        return this.tone.intervalToFrequencyRatio(val / 10);
+        return intervalToFrequencyRatio(val / 10);
     }
 
+    /**
+    * Convert a musical interval to a frequency ratio.
+    * With thanks to Tone.js: https://github.com/Tonejs/Tone.js
+    * @param {number} interval - a musical interval, in semitones
+    * @returns {number} a frequency ratio
+    */
+    intervalToFrequencyRatio (interval) {
+        return Math.pow(2, (interval/12));
+    };
+
     /**
     * Update a sound player's playback rate using the current ratio for the effect
     * @param {object} player - a SoundPlayer object

From e515bf4026a0a306878adae4544a9462f0c44f44 Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Mon, 19 Jun 2017 17:40:53 -0400
Subject: [PATCH 02/14] Cleanup

---
 src/effects/PitchEffect.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/effects/PitchEffect.js b/src/effects/PitchEffect.js
index f482185..2281eba 100644
--- a/src/effects/PitchEffect.js
+++ b/src/effects/PitchEffect.js
@@ -60,7 +60,7 @@ class PitchEffect {
     */
     intervalToFrequencyRatio (interval) {
         return Math.pow(2, (interval/12));
-    };
+    }
 
     /**
     * Update a sound player's playback rate using the current ratio for the effect

From 865d3cde88fa36d0b15694c87a83e1775f24b105 Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Mon, 19 Jun 2017 17:41:08 -0400
Subject: [PATCH 03/14] Correctly call this.intervalToFrequencyRatio

---
 src/effects/PitchEffect.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/effects/PitchEffect.js b/src/effects/PitchEffect.js
index 2281eba..7cebc44 100644
--- a/src/effects/PitchEffect.js
+++ b/src/effects/PitchEffect.js
@@ -49,7 +49,7 @@ class PitchEffect {
     * @returns {number} a playback ratio
     */
     getRatio (val) {
-        return intervalToFrequencyRatio(val / 10);
+        return this.intervalToFrequencyRatio(val / 10);
     }
 
     /**

From 03034dd2f7dcbb602cb01dbbe38edc822b969edc Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Tue, 20 Jun 2017 16:50:02 -0400
Subject: [PATCH 04/14] Remove dependency on Tone.js

---
 package.json             |  1 -
 src/ADPCMSoundDecoder.js |  9 ++++---
 src/DrumPlayer.js        | 29 +++++++++++++++-------
 src/InstrumentPlayer.js  | 12 ++++-----
 src/SoundPlayer.js       | 16 ++++++------
 src/effects/PanEffect.js | 15 ++++++------
 src/index.js             | 53 +++++++++++++++++++++-------------------
 7 files changed, 75 insertions(+), 60 deletions(-)

diff --git a/package.json b/package.json
index 351192c..60f5821 100644
--- a/package.json
+++ b/package.json
@@ -30,7 +30,6 @@
     "json": "^9.0.6",
     "minilog": "^3.0.1",
     "soundfont-player": "0.10.5",
-    "tone": "0.9.0",
     "travis-after-all": "^1.4.4",
     "webpack": "2.4.0"
   }
diff --git a/src/ADPCMSoundDecoder.js b/src/ADPCMSoundDecoder.js
index e9e0b00..3a29d79 100644
--- a/src/ADPCMSoundDecoder.js
+++ b/src/ADPCMSoundDecoder.js
@@ -1,5 +1,4 @@
 const ArrayBufferStream = require('./ArrayBufferStream');
-const Tone = require('tone');
 const log = require('./log');
 
 /**
@@ -10,6 +9,9 @@ const log = require('./log');
  * https://github.com/LLK/scratch-flash/blob/master/src/sound/WAVFile.as
  */
 class ADPCMSoundDecoder {
+    constructor (context) {
+        this.context = context;
+    }
     /**
      * Data used by the decompression algorithm
      * @type {Array}
@@ -40,7 +42,7 @@ class ADPCMSoundDecoder {
      * Decode an ADPCM sound stored in an ArrayBuffer and return a promise
      * with the decoded audio buffer.
      * @param  {ArrayBuffer} audioData - containing ADPCM encoded wav audio
-     * @return {Tone.Buffer} the decoded audio buffer
+     * @return {AudioBuffer} the decoded audio buffer
      */
     decode (audioData) {
 
@@ -77,8 +79,7 @@ class ADPCMSoundDecoder {
 
             const samples = this.imaDecompress(this.extractChunk('data', stream), this.adpcmBlockSize);
 
-            // @todo this line is the only place Tone is used here, should be possible to remove
-            const buffer = Tone.context.createBuffer(1, samples.length, this.samplesPerSecond);
+            const buffer = this.context.createBuffer(1, samples.length, this.samplesPerSecond);
 
             // @todo optimize this? e.g. replace the divide by storing 1/32768 and multiply?
             for (let i = 0; i < samples.length; i++) {
diff --git a/src/DrumPlayer.js b/src/DrumPlayer.js
index f4d0fde..b020542 100644
--- a/src/DrumPlayer.js
+++ b/src/DrumPlayer.js
@@ -1,14 +1,13 @@
 const SoundPlayer = require('./SoundPlayer');
-const Tone = require('tone');
 
 class DrumPlayer {
     /**
      * A prototype for the drum sound functionality that can load drum sounds, play, and stop them.
-     * @param {Tone.Gain} outputNode - a webAudio node that the drum sounds will send their output to
+     * @param {AudioContext} context - a webAudio context
      * @constructor
      */
-    constructor (outputNode) {
-        this.outputNode = outputNode;
+    constructor (context) {
+        this.context = context;
 
         const baseUrl = 'https://raw.githubusercontent.com/LLK/scratch-audio/develop/sound-files/drums/';
         const fileNames = [
@@ -35,9 +34,21 @@ class DrumPlayer {
         this.drumSounds = [];
 
         for (let i = 0; i < fileNames.length; i++) {
-            const url = `${baseUrl + fileNames[i]}_22k.wav`;
-            this.drumSounds[i] = new SoundPlayer(this.outputNode);
-            this.drumSounds[i].setBuffer(new Tone.Buffer(url));
+            this.drumSounds[i] = new SoundPlayer(this.context);
+
+            // download and decode the drum sounds
+            // @todo: use scratch-storage to manage these sound files
+            const url = baseUrl + fileNames[i] + '_22k.wav';
+            const request = new XMLHttpRequest();
+            request.open('GET', url, true);
+            request.responseType = 'arraybuffer';
+            request.onload = () => {
+                const audioData = request.response;
+                this.context.decodeAudioData(audioData).then(buffer => {
+                    this.drumSounds[i].setBuffer(buffer);
+                });
+            };
+            request.send();
         }
     }
 
@@ -46,10 +57,10 @@ class DrumPlayer {
      * The parameter for output node allows sprites or clones to send the drum sound
      * to their individual audio effect chains.
      * @param  {number} drum - the drum number to play (0-indexed)
-     * @param  {Tone.Gain} outputNode - a node to send the output to
+     * @param  {AudioNode} outputNode - a node to send the output to
      */
     play (drum, outputNode) {
-        this.drumSounds[drum].outputNode = outputNode;
+        this.drumSounds[drum].connect(outputNode);
         this.drumSounds[drum].start();
     }
 
diff --git a/src/InstrumentPlayer.js b/src/InstrumentPlayer.js
index d7e3a77..627e910 100644
--- a/src/InstrumentPlayer.js
+++ b/src/InstrumentPlayer.js
@@ -1,4 +1,3 @@
-const Tone = require('tone');
 const Soundfont = require('soundfont-player');
 
 class InstrumentPlayer {
@@ -10,11 +9,12 @@ class InstrumentPlayer {
      * play note or set instrument block runs, causing a delay of a few seconds.
      * Using this library we don't have a way to set the volume, sustain the note beyond the sample
      * duration, or run it through the sprite-specific audio effects.
-     * @param {Tone.Gain} outputNode - a webAudio node that the instrument will send its output to
+     * @param {AudioNode} outputNode - a webAudio node that the instrument will send its output to
      * @constructor
      */
-    constructor (outputNode) {
-        this.outputNode = outputNode;
+    constructor (context) {
+        this.context = context;
+        this.outputNode = null;
 
         // Instrument names used by Musyng Kite soundfont, in order to
         // match scratch instruments
@@ -42,7 +42,7 @@ class InstrumentPlayer {
         this.loadInstrument(instrumentNum)
             .then(() => {
                 this.instruments[instrumentNum].play(
-                    note, Tone.context.currentTime, {
+                    note, this.context.currentTime, {
                         duration: sec,
                         gain: gain
                     }
@@ -59,7 +59,7 @@ class InstrumentPlayer {
         if (this.instruments[instrumentNum]) {
             return Promise.resolve();
         }
-        return Soundfont.instrument(Tone.context, this.instrumentNames[instrumentNum])
+        return Soundfont.instrument(this.context, this.instrumentNames[instrumentNum])
                 .then(inst => {
                     inst.connect(this.outputNode);
                     this.instruments[instrumentNum] = inst;
diff --git a/src/SoundPlayer.js b/src/SoundPlayer.js
index debf85e..1a67b7f 100644
--- a/src/SoundPlayer.js
+++ b/src/SoundPlayer.js
@@ -1,13 +1,13 @@
-const Tone = require('tone');
 const log = require('./log');
 
 /**
  * A SoundPlayer stores an audio buffer, and plays it
  */
 class SoundPlayer {
-    constructor () {
+    constructor (context) {
+        this.context = context;
         this.outputNode = null;
-        this.buffer = new Tone.Buffer();
+        this.buffer = null;
         this.bufferSource = null;
         this.playbackRate = 1;
         this.isPlaying = false;
@@ -15,7 +15,7 @@ class SoundPlayer {
 
     /**
      * Connect the SoundPlayer to an output node
-     * @param  {Tone.Gain} node - an output node to connect to
+     * @param {GainNode} node - an output node to connect to
      */
     connect (node) {
         this.outputNode = node;
@@ -23,7 +23,7 @@ class SoundPlayer {
 
     /**
      * Set an audio buffer
-     * @param {Tone.Buffer} buffer Buffer to set
+     * @param {AudioBuffer} buffer - Buffer to set
      */
     setBuffer (buffer) {
         this.buffer = buffer;
@@ -55,13 +55,13 @@ class SoundPlayer {
      * The web audio framework requires a new audio buffer source node for each playback
      */
     start () {
-        if (!this.buffer || !this.buffer.loaded) {
+        if (!this.buffer) {
             log.warn('tried to play a sound that was not loaded yet');
             return;
         }
 
-        this.bufferSource = Tone.context.createBufferSource();
-        this.bufferSource.buffer = this.buffer.get();
+        this.bufferSource = this.context.createBufferSource();
+        this.bufferSource.buffer = this.buffer;
         this.bufferSource.playbackRate.value = this.playbackRate;
         this.bufferSource.connect(this.outputNode);
         this.bufferSource.start();
diff --git a/src/effects/PanEffect.js b/src/effects/PanEffect.js
index b091600..86e55eb 100644
--- a/src/effects/PanEffect.js
+++ b/src/effects/PanEffect.js
@@ -1,17 +1,14 @@
-const Tone = require('tone');
-
 /**
 * A pan effect, which moves the sound to the left or right between the speakers
 * Effect value of -100 puts the audio entirely on the left channel,
 * 0 centers it, 100 puts it on the right.
 * Clamped -100 to 100
 */
-class PanEffect extends Tone.Effect {
-    constructor () {
-        super();
+class PanEffect {
+    constructor (context) {
+        this.context = context;
+        this.panner = this.context.createStereoPanner();
         this.value = 0;
-        this.panner = new Tone.Panner();
-        this.effectSend.chain(this.panner, this.effectReturn);
     }
 
     /**
@@ -23,6 +20,10 @@ class PanEffect extends Tone.Effect {
         this.panner.pan.value = this.value / 100;
     }
 
+    connect (node) {
+        this.panner.connect(node);
+    }
+
     /**
     * Change the effect value
     * @param {number} val - the value to change the effect by
diff --git a/src/index.js b/src/index.js
index b794c22..149f843 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,5 +1,4 @@
 const log = require('./log');
-const Tone = require('tone');
 
 const PitchEffect = require('./effects/PitchEffect');
 const PanEffect = require('./effects/PanEffect');
@@ -25,15 +24,15 @@ class AudioPlayer {
     constructor (audioEngine) {
         this.audioEngine = audioEngine;
 
-        // effects setup
+        // Create the audio effects
         this.pitchEffect = new PitchEffect();
-        this.panEffect = new PanEffect();
+        this.panEffect = new PanEffect(this.audioEngine.context);
 
-        // the effects are chained to an effects node for this player, then to the main audio engine
-        // audio is sent from each soundplayer, through the effects in order, then to the global effects
-        // note that the pitch effect works differently - it sets the playback rate for each soundplayer
-        this.effectsNode = new Tone.Gain();
-        this.effectsNode.chain(this.panEffect, this.audioEngine.input);
+        // Chain the audio effects together
+        // effectsNode -> panEffect -> audioEngine.input -> destination (speakers)
+        this.effectsNode = this.audioEngine.context.createGain();
+        this.effectsNode.connect(this.panEffect.panner);
+        this.panEffect.connect(this.audioEngine.input);
 
         // reset effects to their default parameters
         this.clearEffects();
@@ -59,7 +58,7 @@ class AudioPlayer {
         }
 
         // create a new soundplayer to play the sound
-        const player = new SoundPlayer();
+        const player = new SoundPlayer(this.audioEngine.context);
         player.setBuffer(this.audioEngine.audioBuffers[md5]);
         player.connect(this.effectsNode);
         this.pitchEffect.updatePlayer(player);
@@ -150,18 +149,22 @@ class AudioPlayer {
  */
 class AudioEngine {
     constructor () {
-        this.input = new Tone.Gain();
-        this.input.connect(Tone.Master);
+        var AudioContext = window.AudioContext || window.webkitAudioContext;
+        this.context = new AudioContext();
+
+        this.input = this.context.createGain();
+        this.input.connect(this.context.destination);
 
         // global tempo in bpm (beats per minute)
         this.currentTempo = 60;
 
         // instrument player for play note blocks
-        this.instrumentPlayer = new InstrumentPlayer(this.input);
+        this.instrumentPlayer = new InstrumentPlayer(this.context);
+        this.instrumentPlayer.outputNode = this.input;
         this.numInstruments = this.instrumentPlayer.instrumentNames.length;
 
         // drum player for play drum blocks
-        this.drumPlayer = new DrumPlayer(this.input);
+        this.drumPlayer = new DrumPlayer(this.context);
         this.numDrums = this.drumPlayer.drumSounds.length;
 
         // a map of md5s to audio buffers, holding sounds for all sprites
@@ -201,10 +204,10 @@ class AudioEngine {
 
         switch (sound.format) {
         case '':
-            loaderPromise = Tone.context.decodeAudioData(bufferCopy);
+            loaderPromise = this.context.decodeAudioData(bufferCopy);
             break;
         case 'adpcm':
-            loaderPromise = (new ADPCMSoundDecoder()).decode(bufferCopy);
+            loaderPromise = (new ADPCMSoundDecoder(this.context)).decode(bufferCopy);
             break;
         default:
             return log.warn('unknown sound format', sound.format);
@@ -213,7 +216,7 @@ class AudioEngine {
         const storedContext = this;
         return loaderPromise.then(
             decodedAudio => {
-                storedContext.audioBuffers[sound.md5] = new Tone.Buffer(decodedAudio);
+                storedContext.audioBuffers[sound.md5] = decodedAudio;
             },
             error => {
                 log.warn('audio data could not be decoded', error);
@@ -289,15 +292,15 @@ class AudioEngine {
      * @return {number} loudness scaled 0 to 100
      */
     getLoudness () {
-        if (!this.mic) {
-            this.mic = new Tone.UserMedia();
-            this.micMeter = new Tone.Meter('level', 0.5);
-            this.mic.open();
-            this.mic.connect(this.micMeter);
-        }
-        if (this.mic && this.mic.state === 'started') {
-            return this.micMeter.value * 100;
-        }
+        // if (!this.mic) {
+        //     this.mic = new Tone.UserMedia();
+        //     this.micMeter = new Tone.Meter('level', 0.5);
+        //     this.mic.open();
+        //     this.mic.connect(this.micMeter);
+        // }
+        // if (this.mic && this.mic.state === 'started') {
+        //     return this.micMeter.value * 100;
+        // }
         return -1;
 
     }

From 2974a5e65b70a0813d9394e9f11c05259f5258b8 Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Tue, 20 Jun 2017 18:34:12 -0400
Subject: [PATCH 05/14] Re-implement loudness block

---
 src/index.js | 47 +++++++++++++++++++++++++++++++++++++----------
 1 file changed, 37 insertions(+), 10 deletions(-)

diff --git a/src/index.js b/src/index.js
index 149f843..ea53ea7 100644
--- a/src/index.js
+++ b/src/index.js
@@ -289,20 +289,47 @@ class AudioEngine {
     /**
      * Get the current loudness of sound received by the microphone.
      * Sound is measured in RMS and smoothed.
+     * Some code adapted from Tone.js: https://github.com/Tonejs/Tone.js
      * @return {number} loudness scaled 0 to 100
      */
     getLoudness () {
-        // if (!this.mic) {
-        //     this.mic = new Tone.UserMedia();
-        //     this.micMeter = new Tone.Meter('level', 0.5);
-        //     this.mic.open();
-        //     this.mic.connect(this.micMeter);
-        // }
-        // if (this.mic && this.mic.state === 'started') {
-        //     return this.micMeter.value * 100;
-        // }
-        return -1;
+        // the microphone has not been set up, try to connect to it
+        if (!this.mic && !this.connectingToMic) {
+            this.connectingToMic = true; // prevent multiple connection attempts
+            navigator.mediaDevices.getUserMedia({audio : true}).then(stream => {
+                this.mic = this.context.createMediaStreamSource(stream);
+                this.analyser = this.context.createAnalyser();
+                this.mic.connect(this.analyser);
+                this.micDataArray = new Float32Array(this.analyser.fftSize);
+            }).catch(err => {
+                log.warn(err)
+            });
+        }
 
+        // if the microphone is set up and active, measure the loudness
+        if (this.mic && this.mic.mediaStream.active) {
+            this.analyser.getFloatTimeDomainData(this.micDataArray);
+            let sum = 0;
+            // compute the RMS of the sound
+            for (let i = 0; i < this.micDataArray.length; i++){
+                sum += Math.pow(this.micDataArray[i], 2);
+            }
+            let rms = Math.sqrt(sum / this.micDataArray.length);
+            // smooth the value, if it is descending
+            if (this._lastValue) {
+                rms = Math.max(rms, this._lastValue * 0.5);
+            }
+            this._lastValue = rms;
+
+            // scale it
+            // @todo figure out why this magic number is needed and remove it!
+            rms *= 1.63;
+            // scale and round the output
+            return Math.round(Math.sqrt(rms) * 100);
+        }
+
+        // if there is no microphone input, return -1
+        return -1;
     }
 
     /**

From 43e04084341fb5487b1e6bc1c052bdeaf63f4a70 Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Wed, 21 Jun 2017 10:46:42 -0400
Subject: [PATCH 06/14] Lint

---
 src/DrumPlayer.js          |  2 +-
 src/InstrumentPlayer.js    |  2 +-
 src/effects/PitchEffect.js |  2 +-
 src/index.js               | 11 ++++++-----
 4 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/src/DrumPlayer.js b/src/DrumPlayer.js
index b020542..3d1aaf4 100644
--- a/src/DrumPlayer.js
+++ b/src/DrumPlayer.js
@@ -38,7 +38,7 @@ class DrumPlayer {
 
             // download and decode the drum sounds
             // @todo: use scratch-storage to manage these sound files
-            const url = baseUrl + fileNames[i] + '_22k.wav';
+            const url = `${baseUrl}${fileNames[i]}_22k.wav`;
             const request = new XMLHttpRequest();
             request.open('GET', url, true);
             request.responseType = 'arraybuffer';
diff --git a/src/InstrumentPlayer.js b/src/InstrumentPlayer.js
index 627e910..bb3484d 100644
--- a/src/InstrumentPlayer.js
+++ b/src/InstrumentPlayer.js
@@ -9,7 +9,7 @@ class InstrumentPlayer {
      * play note or set instrument block runs, causing a delay of a few seconds.
      * Using this library we don't have a way to set the volume, sustain the note beyond the sample
      * duration, or run it through the sprite-specific audio effects.
-     * @param {AudioNode} outputNode - a webAudio node that the instrument will send its output to
+     * @param {AudioContext} context - a webAudio context
      * @constructor
      */
     constructor (context) {
diff --git a/src/effects/PitchEffect.js b/src/effects/PitchEffect.js
index 7cebc44..3de5c5b 100644
--- a/src/effects/PitchEffect.js
+++ b/src/effects/PitchEffect.js
@@ -59,7 +59,7 @@ class PitchEffect {
     * @returns {number} a frequency ratio
     */
     intervalToFrequencyRatio (interval) {
-        return Math.pow(2, (interval/12));
+        return Math.pow(2, (interval / 12));
     }
 
     /**
diff --git a/src/index.js b/src/index.js
index ea53ea7..ff638ba 100644
--- a/src/index.js
+++ b/src/index.js
@@ -149,7 +149,7 @@ class AudioPlayer {
  */
 class AudioEngine {
     constructor () {
-        var AudioContext = window.AudioContext || window.webkitAudioContext;
+        const AudioContext = window.AudioContext || window.webkitAudioContext;
         this.context = new AudioContext();
 
         this.input = this.context.createGain();
@@ -200,7 +200,7 @@ class AudioEngine {
         let loaderPromise = null;
 
         // Make a copy of the buffer because decoding detaches the original buffer
-        var bufferCopy = sound.data.buffer.slice(0);
+        const bufferCopy = sound.data.buffer.slice(0);
 
         switch (sound.format) {
         case '':
@@ -296,13 +296,14 @@ class AudioEngine {
         // the microphone has not been set up, try to connect to it
         if (!this.mic && !this.connectingToMic) {
             this.connectingToMic = true; // prevent multiple connection attempts
-            navigator.mediaDevices.getUserMedia({audio : true}).then(stream => {
+            navigator.mediaDevices.getUserMedia({audio: true}).then(stream => {
                 this.mic = this.context.createMediaStreamSource(stream);
                 this.analyser = this.context.createAnalyser();
                 this.mic.connect(this.analyser);
                 this.micDataArray = new Float32Array(this.analyser.fftSize);
-            }).catch(err => {
-                log.warn(err)
+            })
+            .catch(err => {
+                log.warn(err);
             });
         }
 

From 90af375b0335a43a77dd24f92a426b5a52c9dd0b Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Wed, 21 Jun 2017 11:23:32 -0400
Subject: [PATCH 07/14] Use arrow functions

---
 src/SoundPlayer.js | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/SoundPlayer.js b/src/SoundPlayer.js
index 1a67b7f..ed73a78 100644
--- a/src/SoundPlayer.js
+++ b/src/SoundPlayer.js
@@ -75,12 +75,11 @@ class SoundPlayer {
      * @return {Promise} a Promise that resolves when the sound finishes playing
      */
     finished () {
-        const storedContext = this;
         return new Promise(resolve => {
-            storedContext.bufferSource.onended = function () {
+            this.bufferSource.onended = () => {
                 this.isPlaying = false;
                 resolve();
-            }.bind(storedContext);
+            };
         });
     }
 }

From 0bc892f03d05564210b24051f48ed97d9f73adfc Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Thu, 22 Jun 2017 10:51:57 -0400
Subject: [PATCH 08/14] =?UTF-8?q?Use=20=E2=80=9CaudioContext=E2=80=9D=20to?=
 =?UTF-8?q?=20refer=20to=20webAudioContext?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/ADPCMSoundDecoder.js | 10 +++++++---
 src/DrumPlayer.js        | 10 +++++-----
 src/InstrumentPlayer.js  | 10 +++++-----
 src/SoundPlayer.js       | 10 +++++++---
 src/effects/PanEffect.js | 10 +++++++---
 src/index.js             | 24 ++++++++++++------------
 6 files changed, 43 insertions(+), 31 deletions(-)

diff --git a/src/ADPCMSoundDecoder.js b/src/ADPCMSoundDecoder.js
index 3a29d79..b970d76 100644
--- a/src/ADPCMSoundDecoder.js
+++ b/src/ADPCMSoundDecoder.js
@@ -9,8 +9,12 @@ const log = require('./log');
  * https://github.com/LLK/scratch-flash/blob/master/src/sound/WAVFile.as
  */
 class ADPCMSoundDecoder {
-    constructor (context) {
-        this.context = context;
+    /**
+     * @param {AudioContext} audioContext - a webAudio context
+     * @constructor
+     */
+    constructor (audioContext) {
+        this.audioContext = audioContext;
     }
     /**
      * Data used by the decompression algorithm
@@ -79,7 +83,7 @@ class ADPCMSoundDecoder {
 
             const samples = this.imaDecompress(this.extractChunk('data', stream), this.adpcmBlockSize);
 
-            const buffer = this.context.createBuffer(1, samples.length, this.samplesPerSecond);
+            const buffer = this.audioContext.createBuffer(1, samples.length, this.samplesPerSecond);
 
             // @todo optimize this? e.g. replace the divide by storing 1/32768 and multiply?
             for (let i = 0; i < samples.length; i++) {
diff --git a/src/DrumPlayer.js b/src/DrumPlayer.js
index 3d1aaf4..8592321 100644
--- a/src/DrumPlayer.js
+++ b/src/DrumPlayer.js
@@ -3,11 +3,11 @@ const SoundPlayer = require('./SoundPlayer');
 class DrumPlayer {
     /**
      * A prototype for the drum sound functionality that can load drum sounds, play, and stop them.
-     * @param {AudioContext} context - a webAudio context
+     * @param {AudioContext} audioContext - a webAudio context
      * @constructor
      */
-    constructor (context) {
-        this.context = context;
+    constructor (audioContext) {
+        this.audioContext = audioContext;
 
         const baseUrl = 'https://raw.githubusercontent.com/LLK/scratch-audio/develop/sound-files/drums/';
         const fileNames = [
@@ -34,7 +34,7 @@ class DrumPlayer {
         this.drumSounds = [];
 
         for (let i = 0; i < fileNames.length; i++) {
-            this.drumSounds[i] = new SoundPlayer(this.context);
+            this.drumSounds[i] = new SoundPlayer(this.audioContext);
 
             // download and decode the drum sounds
             // @todo: use scratch-storage to manage these sound files
@@ -44,7 +44,7 @@ class DrumPlayer {
             request.responseType = 'arraybuffer';
             request.onload = () => {
                 const audioData = request.response;
-                this.context.decodeAudioData(audioData).then(buffer => {
+                this.audioContext.decodeAudioData(audioData).then(buffer => {
                     this.drumSounds[i].setBuffer(buffer);
                 });
             };
diff --git a/src/InstrumentPlayer.js b/src/InstrumentPlayer.js
index bb3484d..87c900f 100644
--- a/src/InstrumentPlayer.js
+++ b/src/InstrumentPlayer.js
@@ -9,11 +9,11 @@ class InstrumentPlayer {
      * play note or set instrument block runs, causing a delay of a few seconds.
      * Using this library we don't have a way to set the volume, sustain the note beyond the sample
      * duration, or run it through the sprite-specific audio effects.
-     * @param {AudioContext} context - a webAudio context
+     * @param {AudioContext} audioContext - a webAudio context
      * @constructor
      */
-    constructor (context) {
-        this.context = context;
+    constructor (audioContext) {
+        this.audioContext = audioContext;
         this.outputNode = null;
 
         // Instrument names used by Musyng Kite soundfont, in order to
@@ -42,7 +42,7 @@ class InstrumentPlayer {
         this.loadInstrument(instrumentNum)
             .then(() => {
                 this.instruments[instrumentNum].play(
-                    note, this.context.currentTime, {
+                    note, this.audioContext.currentTime, {
                         duration: sec,
                         gain: gain
                     }
@@ -59,7 +59,7 @@ class InstrumentPlayer {
         if (this.instruments[instrumentNum]) {
             return Promise.resolve();
         }
-        return Soundfont.instrument(this.context, this.instrumentNames[instrumentNum])
+        return Soundfont.instrument(this.audioContext, this.instrumentNames[instrumentNum])
                 .then(inst => {
                     inst.connect(this.outputNode);
                     this.instruments[instrumentNum] = inst;
diff --git a/src/SoundPlayer.js b/src/SoundPlayer.js
index ed73a78..35e9e67 100644
--- a/src/SoundPlayer.js
+++ b/src/SoundPlayer.js
@@ -4,8 +4,12 @@ const log = require('./log');
  * A SoundPlayer stores an audio buffer, and plays it
  */
 class SoundPlayer {
-    constructor (context) {
-        this.context = context;
+    /**
+     * @param {AudioContext} audioContext - a webAudio context
+     * @constructor
+     */
+    constructor (audioContext) {
+        this.audioContext = audioContext;
         this.outputNode = null;
         this.buffer = null;
         this.bufferSource = null;
@@ -60,7 +64,7 @@ class SoundPlayer {
             return;
         }
 
-        this.bufferSource = this.context.createBufferSource();
+        this.bufferSource = this.audioContext.createBufferSource();
         this.bufferSource.buffer = this.buffer;
         this.bufferSource.playbackRate.value = this.playbackRate;
         this.bufferSource.connect(this.outputNode);
diff --git a/src/effects/PanEffect.js b/src/effects/PanEffect.js
index 86e55eb..8374243 100644
--- a/src/effects/PanEffect.js
+++ b/src/effects/PanEffect.js
@@ -5,9 +5,13 @@
 * Clamped -100 to 100
 */
 class PanEffect {
-    constructor (context) {
-        this.context = context;
-        this.panner = this.context.createStereoPanner();
+     /**
+     * @param {AudioContext} audioContext - a webAudio context
+     * @constructor
+     */
+    constructor (audioContext) {
+        this.audioContext = audioContext;
+        this.panner = this.audioContext.createStereoPanner();
         this.value = 0;
     }
 
diff --git a/src/index.js b/src/index.js
index ff638ba..49dfdf2 100644
--- a/src/index.js
+++ b/src/index.js
@@ -26,11 +26,11 @@ class AudioPlayer {
 
         // Create the audio effects
         this.pitchEffect = new PitchEffect();
-        this.panEffect = new PanEffect(this.audioEngine.context);
+        this.panEffect = new PanEffect(this.audioEngine.audioContext);
 
         // Chain the audio effects together
         // effectsNode -> panEffect -> audioEngine.input -> destination (speakers)
-        this.effectsNode = this.audioEngine.context.createGain();
+        this.effectsNode = this.audioEngine.audioContext.createGain();
         this.effectsNode.connect(this.panEffect.panner);
         this.panEffect.connect(this.audioEngine.input);
 
@@ -58,7 +58,7 @@ class AudioPlayer {
         }
 
         // create a new soundplayer to play the sound
-        const player = new SoundPlayer(this.audioEngine.context);
+        const player = new SoundPlayer(this.audioEngine.audioContext);
         player.setBuffer(this.audioEngine.audioBuffers[md5]);
         player.connect(this.effectsNode);
         this.pitchEffect.updatePlayer(player);
@@ -150,21 +150,21 @@ class AudioPlayer {
 class AudioEngine {
     constructor () {
         const AudioContext = window.AudioContext || window.webkitAudioContext;
-        this.context = new AudioContext();
+        this.audioContext = new AudioContext();
 
-        this.input = this.context.createGain();
-        this.input.connect(this.context.destination);
+        this.input = this.audioContext.createGain();
+        this.input.connect(this.audioContext.destination);
 
         // global tempo in bpm (beats per minute)
         this.currentTempo = 60;
 
         // instrument player for play note blocks
-        this.instrumentPlayer = new InstrumentPlayer(this.context);
+        this.instrumentPlayer = new InstrumentPlayer(this.audioContext);
         this.instrumentPlayer.outputNode = this.input;
         this.numInstruments = this.instrumentPlayer.instrumentNames.length;
 
         // drum player for play drum blocks
-        this.drumPlayer = new DrumPlayer(this.context);
+        this.drumPlayer = new DrumPlayer(this.audioContext);
         this.numDrums = this.drumPlayer.drumSounds.length;
 
         // a map of md5s to audio buffers, holding sounds for all sprites
@@ -204,10 +204,10 @@ class AudioEngine {
 
         switch (sound.format) {
         case '':
-            loaderPromise = this.context.decodeAudioData(bufferCopy);
+            loaderPromise = this.audioContext.decodeAudioData(bufferCopy);
             break;
         case 'adpcm':
-            loaderPromise = (new ADPCMSoundDecoder(this.context)).decode(bufferCopy);
+            loaderPromise = (new ADPCMSoundDecoder(this.audioContext)).decode(bufferCopy);
             break;
         default:
             return log.warn('unknown sound format', sound.format);
@@ -297,8 +297,8 @@ class AudioEngine {
         if (!this.mic && !this.connectingToMic) {
             this.connectingToMic = true; // prevent multiple connection attempts
             navigator.mediaDevices.getUserMedia({audio: true}).then(stream => {
-                this.mic = this.context.createMediaStreamSource(stream);
-                this.analyser = this.context.createAnalyser();
+                this.mic = this.audioContext.createMediaStreamSource(stream);
+                this.analyser = this.audioContext.createAnalyser();
                 this.mic.connect(this.analyser);
                 this.micDataArray = new Float32Array(this.analyser.fftSize);
             })

From 66b4ae379568340c4caf1f5e3eaf5fe3b216e7e6 Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Thu, 22 Jun 2017 10:54:52 -0400
Subject: [PATCH 09/14] Remove unused variable

---
 src/index.js | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/index.js b/src/index.js
index 49dfdf2..c8a4488 100644
--- a/src/index.js
+++ b/src/index.js
@@ -172,7 +172,6 @@ class AudioEngine {
 
         // microphone, for measuring loudness, with a level meter analyzer
         this.mic = null;
-        this.micMeter = null;
     }
 
     /**

From b7ff586ca1459ba8351dfd766bcb944e085e0fd5 Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Thu, 22 Jun 2017 11:06:12 -0400
Subject: [PATCH 10/14] Inline the interval to frequency function

---
 src/effects/PitchEffect.js | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/src/effects/PitchEffect.js b/src/effects/PitchEffect.js
index 3de5c5b..4d04736 100644
--- a/src/effects/PitchEffect.js
+++ b/src/effects/PitchEffect.js
@@ -49,16 +49,8 @@ class PitchEffect {
     * @returns {number} a playback ratio
     */
     getRatio (val) {
-        return this.intervalToFrequencyRatio(val / 10);
-    }
-
-    /**
-    * Convert a musical interval to a frequency ratio.
-    * With thanks to Tone.js: https://github.com/Tonejs/Tone.js
-    * @param {number} interval - a musical interval, in semitones
-    * @returns {number} a frequency ratio
-    */
-    intervalToFrequencyRatio (interval) {
+        const interval = val / 10;
+        // Convert the musical interval in semitones to a frequency ratio
         return Math.pow(2, (interval / 12));
     }
 

From a081333ddd19994bb24095becefc276f21376cb8 Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Thu, 22 Jun 2017 11:07:24 -0400
Subject: [PATCH 11/14] Fix comment

---
 src/index.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/index.js b/src/index.js
index c8a4488..7b5f191 100644
--- a/src/index.js
+++ b/src/index.js
@@ -29,7 +29,7 @@ class AudioPlayer {
         this.panEffect = new PanEffect(this.audioEngine.audioContext);
 
         // Chain the audio effects together
-        // effectsNode -> panEffect -> audioEngine.input -> destination (speakers)
+        // effectsNode -> panEffect -> audioEngine.input
         this.effectsNode = this.audioEngine.audioContext.createGain();
         this.effectsNode.connect(this.panEffect.panner);
         this.panEffect.connect(this.audioEngine.input);

From dba8c6f91ddbad2331f40d3d352018a0d3e18562 Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Fri, 23 Jun 2017 10:59:10 -0400
Subject: [PATCH 12/14] Adjust loudness smoothing

---
 src/index.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/index.js b/src/index.js
index 7b5f191..3cc959d 100644
--- a/src/index.js
+++ b/src/index.js
@@ -317,7 +317,7 @@ class AudioEngine {
             let rms = Math.sqrt(sum / this.micDataArray.length);
             // smooth the value, if it is descending
             if (this._lastValue) {
-                rms = Math.max(rms, this._lastValue * 0.5);
+                rms = Math.max(rms, this._lastValue * 0.6);
             }
             this._lastValue = rms;
 

From 5add85bd60f6e4c82996666d21560dca5d4e5e60 Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Fri, 23 Jun 2017 11:58:04 -0400
Subject: [PATCH 13/14] Fix comments

---
 src/index.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/index.js b/src/index.js
index 3cc959d..c5fc058 100644
--- a/src/index.js
+++ b/src/index.js
@@ -292,7 +292,7 @@ class AudioEngine {
      * @return {number} loudness scaled 0 to 100
      */
     getLoudness () {
-        // the microphone has not been set up, try to connect to it
+        // The microphone has not been set up, so try to connect to it
         if (!this.mic && !this.connectingToMic) {
             this.connectingToMic = true; // prevent multiple connection attempts
             navigator.mediaDevices.getUserMedia({audio: true}).then(stream => {
@@ -306,7 +306,7 @@ class AudioEngine {
             });
         }
 
-        // if the microphone is set up and active, measure the loudness
+        // If the microphone is set up and active, measure the loudness
         if (this.mic && this.mic.mediaStream.active) {
             this.analyser.getFloatTimeDomainData(this.micDataArray);
             let sum = 0;

From dd0d9556ed53783e4f19a62387c026b7fb6b8767 Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Fri, 23 Jun 2017 13:13:30 -0400
Subject: [PATCH 14/14] Explain loudness scaling, and clamp to 100

---
 src/index.js | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/index.js b/src/index.js
index c5fc058..a0841d9 100644
--- a/src/index.js
+++ b/src/index.js
@@ -321,11 +321,14 @@ class AudioEngine {
             }
             this._lastValue = rms;
 
-            // scale it
-            // @todo figure out why this magic number is needed and remove it!
+            // Scale the measurement so it's more sensitive to quieter sounds
             rms *= 1.63;
-            // scale and round the output
-            return Math.round(Math.sqrt(rms) * 100);
+            rms = Math.sqrt(rms);
+            // Scale it up to 0-100 and round
+            rms = Math.round(rms * 100);
+            // Prevent it from going above 100
+            rms = Math.min(rms, 100);
+            return rms;
         }
 
         // if there is no microphone input, return -1