Merge pull request #89 from LLK/green-audio-player

Green audio player

src/AudioPlayer.js

@@ -2,7 +2,7 @@ const PanEffect = require('./effects/PanEffect');
 const PitchEffect = require('./effects/PitchEffect');
 const VolumeEffect = require('./effects/VolumeEffect');
 
-const SoundPlayer = require('./SoundPlayer');
+const SoundPlayer = require('./GreenPlayer');
 
 class AudioPlayer {
     /**
@@ -17,7 +17,7 @@ class AudioPlayer {
 
         this.outputNode = this.audioEngine.audioContext.createGain();
 
-        // Create the audio effects
+        // Create the audio effects.
         const volumeEffect = new VolumeEffect(this.audioEngine, this, null);
         const pitchEffect = new PitchEffect(this.audioEngine, this, volumeEffect);
         const panEffect = new PanEffect(this.audioEngine, this, pitchEffect);
@@ -33,12 +33,11 @@ class AudioPlayer {
         pitchEffect.connect(panEffect);
         volumeEffect.connect(pitchEffect);
 
-        // reset effects to their default parameters
+        // Reset effects to their default parameters.
         this.clearEffects();
 
-        // sound players that are currently playing, indexed by the sound's
-        // soundId
-        this.activeSoundPlayers = {};
+        // SoundPlayers mapped by sound id.
+        this.soundPlayers = {};
     }
 
     /**
@@ -55,7 +54,19 @@ class AudioPlayer {
      *     players
      */
     getSoundPlayers () {
-        return this.activeSoundPlayers;
+        return this.soundPlayers;
+    }
+
+    /**
+     * Add a SoundPlayer instance to soundPlayers map.
+     * @param {SoundPlayer} soundPlayer - SoundPlayer instance to add
+     */
+    addSoundPlayer (soundPlayer) {
+        this.soundPlayers[soundPlayer.id] = soundPlayer;
+
+        for (const effectName in this.effects) {
+            this.effects[effectName].update();
+        }
     }
 
     /**
@@ -64,37 +75,16 @@ class AudioPlayer {
      * @return {Promise} a Promise that resolves when the sound finishes playing
      */
     playSound (soundId) {
-        // if this sound is not in the audio engine, return
-        if (!this.audioEngine.audioBuffers[soundId]) {
-            return;
-        }
-
-        // if this sprite or clone is already playing this sound, stop it first
-        if (this.activeSoundPlayers[soundId]) {
-            this.activeSoundPlayers[soundId].stop();
-        }
-
         // create a new soundplayer to play the sound
-        const player = new SoundPlayer(this.audioEngine.audioContext);
-        player.setBuffer(this.audioEngine.audioBuffers[soundId]);
-        player.connect(this.outputNode);
-        player.start();
-
-        // add it to the list of active sound players
-        this.activeSoundPlayers[soundId] = player;
-        for (const effectName in this.effects) {
-            this.effects[effectName].update();
-        }
-
-        // remove sounds that are not playing from the active sound players
-        // array
-        for (const id in this.activeSoundPlayers) {
-            if (this.activeSoundPlayers.hasOwnProperty(id)) {
-                if (!this.activeSoundPlayers[id].isPlaying) {
-                    delete this.activeSoundPlayers[id];
-                }
-            }
+        if (!this.soundPlayers[soundId]) {
+            this.addSoundPlayer(new SoundPlayer(
+                this.audioEngine,
+                {id: soundId, buffer: this.audioEngine.audioBuffers[soundId]}
+            ));
         }
+        const player = this.soundPlayers[soundId];
+        player.connect(this);
+        player.play();
 
         return player.finished();
     }
@@ -104,8 +94,8 @@ class AudioPlayer {
      */
     stopAllSounds () {
         // stop all active sound players
-        for (const soundId in this.activeSoundPlayers) {
-            this.activeSoundPlayers[soundId].stop();
+        for (const soundId in this.soundPlayers) {
+            this.soundPlayers[soundId].stop();
         }
     }
 

src/GreenPlayer.js

@@ -31,9 +31,18 @@ class SoundPlayer extends EventEmitter {
 
         this.initialized = false;
         this.isPlaying = false;
+        this.startingUntil = 0;
         this.playbackRate = 1;
     }
 
+    /**
+     * Is plaback currently starting?
+     * @type {boolean}
+     */
+    get isStarting () {
+        return this.isPlaying && this.startingUntil > this.audioEngine.audioContext.currentTime;
+    }
+
     /**
      * Handle any event we have told the output node to listen for.
      * @param {Event} event - dom event to handle
@@ -146,6 +155,7 @@ class SoundPlayer extends EventEmitter {
         const taken = new SoundPlayer(this.audioEngine, this);
         taken.playbackRate = this.playbackRate;
         if (this.isPlaying) {
+            taken.startingUntil = this.startingUntil;
             taken.isPlaying = this.isPlaying;
             taken.initialize();
             taken.outputNode.disconnect();
@@ -168,6 +178,7 @@ class SoundPlayer extends EventEmitter {
         }
         this.volumeEffect = null;
         this.initialized = false;
+        this.startingUntil = 0;
         this.isPlaying = false;
 
         return taken;
@@ -180,6 +191,10 @@ class SoundPlayer extends EventEmitter {
      * out.
      */
     play () {
+        if (this.isStarting) {
+            return;
+        }
+
         if (this.isPlaying) {
             // Spawn a Player with the current buffer source, and play for a
             // short period until its volume is 0 and release it to be
@@ -198,6 +213,8 @@ class SoundPlayer extends EventEmitter {
 
         this.isPlaying = true;
 
+        this.startingUntil = this.audioEngine.audioContext.currentTime + this.audioEngine.DECAY_TIME;
+
         this.emit('play');
     }
 
@@ -213,6 +230,7 @@ class SoundPlayer extends EventEmitter {
         this.outputNode.stop(this.audioEngine.audioContext.currentTime + this.audioEngine.DECAY_TIME);
 
         this.isPlaying = false;
+        this.startingUntil = 0;
 
         this.emit('stop');
     }
@@ -228,6 +246,7 @@ class SoundPlayer extends EventEmitter {
         this.outputNode.stop();
 
         this.isPlaying = false;
+        this.startingUntil = 0;
 
         this.emit('stop');
     }