mirror of
https://github.com/doublespeakgames/adarkroom.git
synced 2026-05-28 08:11:54 +08:00
refactor audio engine: simplified gain channels, improve fading between audio, rename functions
This commit is contained in:
jorsi
+106
-115
@@ -4,158 +4,157 @@
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var AudioEngine = {
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FADE_TIME: 1,
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AUDIO_BUFFER_CACHE: {},
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_audioPreloaded: false,
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audioContext: null,
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master: null,
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tracks: {
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'bg1': null,
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'bg2': null,
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'events': null,
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'sfx': null
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_audioContext: null,
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_master: null,
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_currentBackgroundMusic: null,
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_currentEventAudio: null,
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_currentSoundEffectAudio: null,
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init: function () {
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AudioEngine._initAudioContext();
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},
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currentBackgroundChannel: 'bg1',
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currentBackgroundAudio: null,
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currentEventAudio: null,
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init: function (options) {
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AudioEngine.initAudioContext();
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},
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initAudioContext: function () {
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_initAudioContext: function () {
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// for legacy browsers
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AudioEngine.audioContext = new (window.AudioContext || window.webkitAudioContext);
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if (AudioEngine.audioContext.state === 'suspended') {
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AudioEngine.audioContext.resume().then(function () {
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AudioEngine.createChannels();
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AudioEngine._audioContext = new (window.AudioContext || window.webkitAudioContext);
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if (AudioEngine._audioContext.state === 'suspended') {
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AudioEngine._audioContext.resume().then(function () {
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AudioEngine._createMasterChannel();
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});
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} else {
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AudioEngine.createChannels();
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AudioEngine._createMasterChannel();
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}
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},
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createChannels: function () {
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_createMasterChannel: function () {
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// create master
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AudioEngine.master = AudioEngine.audioContext.createGain();
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AudioEngine.master.gain.setValueAtTime(1.0, AudioEngine.audioContext.currentTime);
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AudioEngine.master.connect(AudioEngine.audioContext.destination);
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// create 4 tracks to output to master
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AudioEngine.tracks['bg1'] = AudioEngine.audioContext.createGain();
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AudioEngine.tracks['bg1'].connect(AudioEngine.master);
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AudioEngine.tracks['bg1'].gain.setValueAtTime(1.0, AudioEngine.audioContext.currentTime);
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AudioEngine.tracks['bg2'] = AudioEngine.audioContext.createGain();
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AudioEngine.tracks['bg2'].connect(AudioEngine.master);
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AudioEngine.tracks['bg2'].gain.setValueAtTime(1.0, AudioEngine.audioContext.currentTime);
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AudioEngine.tracks['events'] = AudioEngine.audioContext.createGain();
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AudioEngine.tracks['events'].connect(AudioEngine.master);
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AudioEngine.tracks['events'].gain.setValueAtTime(1.0, AudioEngine.audioContext.currentTime);
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AudioEngine.tracks['sfx'] = AudioEngine.audioContext.createGain();
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AudioEngine.tracks['sfx'].connect(AudioEngine.master);
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AudioEngine.tracks['sfx'].gain.setValueAtTime(1.0, AudioEngine.audioContext.currentTime);
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AudioEngine._master = AudioEngine._audioContext.createGain();
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AudioEngine._master.gain.setValueAtTime(1.0, AudioEngine._audioContext.currentTime);
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AudioEngine._master.connect(AudioEngine._audioContext.destination);
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},
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options: {}, // Nothing for now,
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_canPlayAudio: function () {
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if (AudioEngine.audioContext.state === 'suspended') {
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if (AudioEngine._audioContext.state === 'suspended') {
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return false;
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}
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return true;
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},
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_getMissingAudioBuffer: function () {
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var buffer = AudioEngine.audioContext.createBuffer(
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// plays beeping sound to indicate missing audio
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var buffer = AudioEngine._audioContext.createBuffer(
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1,
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AudioEngine.audioContext.sampleRate,
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AudioEngine.audioContext.sampleRate
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AudioEngine._audioContext.sampleRate,
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AudioEngine._audioContext.sampleRate
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);
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// Fill the buffer
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var bufferData = buffer.getChannelData(0);
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for (var i = 0; i < buffer.length / 2; i++) {
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bufferData[i] = Math.sin(i * .05) / 2;
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bufferData[i] = Math.sin(i * .05) / 4; // max .25 gain value
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}
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return buffer;
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},
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_playSound: function (buffer) {
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if (!AudioEngine._canPlayAudio()) return;
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var source = AudioEngine.audioContext.createBufferSource();
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var source = AudioEngine._audioContext.createBufferSource();
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source.buffer = buffer;
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source.connect(AudioEngine.tracks['sfx']);
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source.start(AudioEngine.audioContext.currentTime);
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source.connect(AudioEngine._master);
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source.start();
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AudioEngine._currentSoundEffectAudio = {
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source: source
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};
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},
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_fadeTrack: function (buffer) {
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_playBackgroundMusic: function (buffer) {
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if (!AudioEngine._canPlayAudio()) return;
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var bufferSource = AudioEngine.audioContext.createBufferSource();
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bufferSource.buffer = buffer;
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bufferSource.loop = true;
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var source = AudioEngine._audioContext.createBufferSource();
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source.buffer = buffer;
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source.loop = true;
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// figure out which background track to start on
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// in order to do crossfade
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var nextBackgroundChannel;
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if (AudioEngine.currentBackgroundChannel === 'bg1') {
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nextBackgroundChannel = 'bg2';
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} else {
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nextBackgroundChannel = 'bg1';
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var envelope = AudioEngine._audioContext.createGain();
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envelope.gain.setValueAtTime(0.0, AudioEngine._audioContext.currentTime);
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var fadeTime = AudioEngine._audioContext.currentTime + AudioEngine.FADE_TIME;
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// fade out current background music
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if (AudioEngine._currentBackgroundMusic) {
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var currentBackgroundGainValue = AudioEngine._currentBackgroundMusic.envelope.gain.value;
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AudioEngine._currentBackgroundMusic.envelope.gain.cancelScheduledValues(AudioEngine._audioContext.currentTime);
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AudioEngine._currentBackgroundMusic.envelope.gain.setValueAtTime(currentBackgroundGainValue, AudioEngine._audioContext.currentTime);
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AudioEngine._currentBackgroundMusic.envelope.gain.linearRampToValueAtTime(0.0, fadeTime);
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AudioEngine._currentBackgroundMusic.source.stop(fadeTime + 0.3); // make sure fade has completed
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}
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// fade in new track
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var fadeTime = AudioEngine.audioContext.currentTime + AudioEngine.FADE_TIME;
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bufferSource.connect(AudioEngine.tracks[nextBackgroundChannel]);
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bufferSource.start(AudioEngine.audioContext.currentTime);
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AudioEngine.tracks[nextBackgroundChannel].gain.setValueAtTime(0.0, AudioEngine.audioContext.currentTime);
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AudioEngine.tracks[nextBackgroundChannel].gain.linearRampToValueAtTime(1.0, fadeTime);
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// fade in new backgorund music
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source.connect(envelope);
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envelope.connect(AudioEngine._master);
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source.start();
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envelope.gain.linearRampToValueAtTime(1.0, fadeTime);
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// fade out old track
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AudioEngine.tracks[AudioEngine.currentBackgroundChannel].gain.linearRampToValueAtTime(0.0, fadeTime);
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if (AudioEngine.currentBackgroundAudio) {
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AudioEngine.currentBackgroundAudio.stop(fadeTime + 0.3); // make sure fade has completed
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}
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// switch background track
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AudioEngine.currentBackgroundChannel = nextBackgroundChannel;
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AudioEngine.currentBackgroundAudio = bufferSource;
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// update current background music
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AudioEngine._currentBackgroundMusic = {
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source: source,
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envelope: envelope
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};
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},
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_playEvent: function (buffer) {
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_playEventMusic: function (buffer) {
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if (!AudioEngine._canPlayAudio()) return;
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var bufferSource = AudioEngine.audioContext.createBufferSource();
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bufferSource.buffer = buffer;
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bufferSource.loop = true;
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var source = AudioEngine._audioContext.createBufferSource();
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source.buffer = buffer;
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source.loop = true;
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var fadeTime = AudioEngine.audioContext.currentTime + AudioEngine.FADE_TIME * 2;
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var envelope = AudioEngine._audioContext.createGain();
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envelope.gain.setValueAtTime(0.0, AudioEngine._audioContext.currentTime);
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// turn down background music
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AudioEngine.tracks['bg1'].gain.linearRampToValueAtTime(0.2, fadeTime);
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AudioEngine.tracks['bg2'].gain.linearRampToValueAtTime(0.2, fadeTime);
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var fadeTime = AudioEngine._audioContext.currentTime + AudioEngine.FADE_TIME * 2;
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// turn down current background music
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if (AudioEngine._currentBackgroundMusic != null) {
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var currentBackgroundGainValue = AudioEngine._currentBackgroundMusic.envelope.gain.value;
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AudioEngine._currentBackgroundMusic.envelope.gain.cancelScheduledValues(AudioEngine._audioContext.currentTime);
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AudioEngine._currentBackgroundMusic.envelope.gain.setValueAtTime(currentBackgroundGainValue, AudioEngine._audioContext.currentTime);
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AudioEngine._currentBackgroundMusic.envelope.gain.linearRampToValueAtTime(0.2, fadeTime);
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}
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// fade in event music
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bufferSource.connect(AudioEngine.tracks['events']);
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bufferSource.start(0);
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AudioEngine.currentEventAudio = bufferSource;
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source.connect(envelope);
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envelope.connect(AudioEngine._master);
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source.start();
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envelope.gain.linearRampToValueAtTime(1.0, fadeTime);
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AudioEngine.tracks['events'].gain.setValueAtTime(0.0, AudioEngine.audioContext.currentTime);
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AudioEngine.tracks['events'].gain.linearRampToValueAtTime(1.0, fadeTime);
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// update reference
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AudioEngine._currentEventAudio = {
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source: source,
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envelope: envelope
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};
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},
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_stopEventMusic: function () {
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var fadeTime = AudioEngine.audioContext.currentTime + AudioEngine.FADE_TIME * 2;
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var fadeTime = AudioEngine._audioContext.currentTime + AudioEngine.FADE_TIME * 2;
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// fade out event music and stop
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AudioEngine.tracks['events'].gain.linearRampToValueAtTime(0.0, fadeTime);
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if (AudioEngine.currentEventAudio) {
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AudioEngine.currentEventAudio.stop(fadeTime + 1); // make sure fade has completed
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AudioEngine.currentEventAudio = null;
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if (AudioEngine._currentEventAudio) {
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var currentEventGainValue = AudioEngine._currentEventAudio.envelope.gain.value;
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AudioEngine._currentEventAudio.envelope.gain.cancelScheduledValues(AudioEngine._audioContext.currentTime);
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AudioEngine._currentEventAudio.envelope.gain.setValueAtTime(currentEventGainValue, AudioEngine._audioContext.currentTime);
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AudioEngine._currentEventAudio.envelope.gain.linearRampToValueAtTime(0.0, fadeTime);
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AudioEngine._currentEventAudio.source.stop(fadeTime + 1); // make sure fade has completed
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AudioEngine._currentEventAudio = null;
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}
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// turn up background music
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AudioEngine.tracks[AudioEngine.currentBackgroundChannel].gain.linearRampToValueAtTime(1.0, fadeTime);
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var currentBackgroundGainValue = AudioEngine._currentBackgroundMusic.envelope.gain.value;
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AudioEngine._currentBackgroundMusic.envelope.gain.cancelScheduledValues(AudioEngine._audioContext.currentTime);
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AudioEngine._currentBackgroundMusic.envelope.gain.setValueAtTime(currentBackgroundGainValue, AudioEngine._audioContext.currentTime);
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AudioEngine._currentBackgroundMusic.envelope.gain.linearRampToValueAtTime(1.0, fadeTime);
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},
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changeMusic: function (src) {
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playBackgroundMusic: function (src) {
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AudioEngine.loadAudioFile(src)
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.then(function (buffer) {
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AudioEngine._fadeTrack(buffer);
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AudioEngine._playBackgroundMusic(buffer);
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});
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},
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playEventMusic: function (src) {
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AudioEngine.loadAudioFile(src)
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.then(function (buffer) {
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AudioEngine._playEvent(buffer);
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AudioEngine._playEventMusic(buffer);
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});
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},
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stopEventMusic: function () {
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@@ -185,37 +184,29 @@ var AudioEngine = {
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return AudioEngine._getMissingAudioBuffer();
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}
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return AudioEngine.audioContext.decodeAudioData(buffer, function (decodedData) {
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return AudioEngine._audioContext.decodeAudioData(buffer, function (decodedData) {
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AudioEngine.AUDIO_BUFFER_CACHE[src] = decodedData;
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return AudioEngine.AUDIO_BUFFER_CACHE[src];
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});
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});
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}
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},
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mute: function () {
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AudioEngine.master.gain.linearRampToValueAtTime(
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0.0,
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AudioEngine.audioContext.currentTime + AudioEngine.FADE_TIME
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);
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},
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getVolume: function () {
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return AudioEngine.master.gain.value;
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},
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setVolume: function (volume, s) {
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if (!AudioEngine.master) return; // master may not be ready yet
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if (!volume) {
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if (AudioEngine._master == null) return; // master may not be ready yet
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if (volume === undefined) {
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volume = 1.0;
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}
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if (!s) {
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if (s === undefined) {
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s = 1.0;
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}
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AudioEngine.master.gain.setValueAtTime(
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AudioEngine.master.gain.value,
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AudioEngine.audioContext.currentTime
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);
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AudioEngine.master.gain.linearRampToValueAtTime(
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// cancel any current schedules and then ramp
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var currentGainValue = AudioEngine._master.gain.value;
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AudioEngine._master.gain.cancelScheduledValues(AudioEngine._audioContext.currentTime);
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AudioEngine._master.gain.setValueAtTime(currentGainValue, AudioEngine._audioContext.currentTime);
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AudioEngine._master.gain.linearRampToValueAtTime(
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volume,
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AudioEngine.audioContext.currentTime + s
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AudioEngine._audioContext.currentTime + s
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);
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}
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};
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