mediocre-blog/assets/trading-in-the-rain/MIDI.js/js/midi/loader.js

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2020-04-27 00:15:15 +00:00
/*
----------------------------------------------------------
MIDI.Plugin : 0.3.4 : 2015-03-26
----------------------------------------------------------
https://github.com/mudcube/MIDI.js
----------------------------------------------------------
Inspired by javax.sound.midi (albeit a super simple version):
http://docs.oracle.com/javase/6/docs/api/javax/sound/midi/package-summary.html
----------------------------------------------------------
Technologies
----------------------------------------------------------
Web MIDI API - no native support yet (jazzplugin)
Web Audio API - firefox 25+, chrome 10+, safari 6+, opera 15+
HTML5 Audio Tag - ie 9+, firefox 3.5+, chrome 4+, safari 4+, opera 9.5+, ios 4+, android 2.3+
----------------------------------------------------------
*/
if (typeof MIDI === 'undefined') MIDI = {};
MIDI.Soundfont = MIDI.Soundfont || {};
MIDI.Player = MIDI.Player || {};
(function(root) { 'use strict';
root.DEBUG = true;
root.USE_XHR = true;
root.soundfontUrl = './soundfont/';
/*
MIDI.loadPlugin({
onsuccess: function() { },
onprogress: function(state, percent) { },
targetFormat: 'mp3', // optionally can force to use MP3 (for instance on mobile networks)
instrument: 'acoustic_grand_piano', // or 1 (default)
instruments: [ 'acoustic_grand_piano', 'acoustic_guitar_nylon' ] // or multiple instruments
});
*/
root.loadPlugin = function(opts) {
if (typeof opts === 'function') {
opts = {onsuccess: opts};
}
root.soundfontUrl = opts.soundfontUrl || root.soundfontUrl;
/// Detect the best type of audio to use
root.audioDetect(function(supports) {
var hash = window.location.hash;
var api = '';
/// use the most appropriate plugin if not specified
if (supports[opts.api]) {
api = opts.api;
} else if (supports[hash.substr(1)]) {
api = hash.substr(1);
} else if (supports.webmidi) {
api = 'webmidi';
} else if (window.AudioContext) { // Chrome
api = 'webaudio';
} else if (window.Audio) { // Firefox
api = 'audiotag';
}
if (connect[api]) {
/// use audio/ogg when supported
if (opts.targetFormat) {
var audioFormat = opts.targetFormat;
} else { // use best quality
var audioFormat = supports['audio/ogg'] ? 'ogg' : 'mp3';
}
/// load the specified plugin
root.__api = api;
root.__audioFormat = audioFormat;
root.supports = supports;
root.loadResource(opts);
}
});
};
/*
root.loadResource({
onsuccess: function() { },
onprogress: function(state, percent) { },
instrument: 'banjo'
})
*/
root.loadResource = function(opts) {
var instruments = opts.instruments || opts.instrument || 'acoustic_grand_piano';
///
if (typeof instruments !== 'object') {
if (instruments || instruments === 0) {
instruments = [instruments];
} else {
instruments = [];
}
}
/// convert numeric ids into strings
for (var i = 0; i < instruments.length; i ++) {
var instrument = instruments[i];
if (instrument === +instrument) { // is numeric
if (root.GM.byId[instrument]) {
instruments[i] = root.GM.byId[instrument].id;
}
}
}
///
opts.format = root.__audioFormat;
opts.instruments = instruments;
///
connect[root.__api](opts);
};
var connect = {
webmidi: function(opts) {
// cant wait for this to be standardized!
root.WebMIDI.connect(opts);
},
audiotag: function(opts) {
// works ok, kinda like a drunken tuna fish, across the board
// http://caniuse.com/audio
requestQueue(opts, 'AudioTag');
},
webaudio: function(opts) {
// works awesome! safari, chrome and firefox support
// http://caniuse.com/web-audio
requestQueue(opts, 'WebAudio');
}
};
var requestQueue = function(opts, context) {
var audioFormat = opts.format;
var instruments = opts.instruments;
var onprogress = opts.onprogress;
var onerror = opts.onerror;
///
var length = instruments.length;
var pending = length;
var waitForEnd = function() {
if (!--pending) {
onprogress && onprogress('load', 1.0);
root[context].connect(opts);
}
};
///
for (var i = 0; i < length; i ++) {
var instrumentId = instruments[i];
if (MIDI.Soundfont[instrumentId]) { // already loaded
waitForEnd();
} else { // needs to be requested
sendRequest(instruments[i], audioFormat, function(evt, progress) {
var fileProgress = progress / length;
var queueProgress = (length - pending) / length;
onprogress && onprogress('load', fileProgress + queueProgress, instrumentId);
}, function() {
waitForEnd();
}, onerror);
}
};
};
var sendRequest = function(instrumentId, audioFormat, onprogress, onsuccess, onerror) {
var soundfontPath = root.soundfontUrl + instrumentId + '-' + audioFormat + '.js';
if (root.USE_XHR) {
root.util.request({
url: soundfontPath,
format: 'text',
onerror: onerror,
onprogress: onprogress,
onsuccess: function(event, responseText) {
var script = document.createElement('script');
script.language = 'javascript';
script.type = 'text/javascript';
script.text = responseText;
document.body.appendChild(script);
///
onsuccess();
}
});
} else {
dom.loadScript.add({
url: soundfontPath,
verify: 'MIDI.Soundfont["' + instrumentId + '"]',
onerror: onerror,
onsuccess: function() {
onsuccess();
}
});
}
};
root.setDefaultPlugin = function(midi) {
for (var key in midi) {
root[key] = midi[key];
}
};
})(MIDI);