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MIDI.js
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fixes #18, keep track of which instrument/note pair is playing on each audiotag 'channel', then on noteOff/chordOff find the right audiotag 'channel' to pause().

master
Brian Stoner 2013-03-12 16:00:29 -04:00
parent a5edc8ae9a
commit 6462f82fde
1 changed files with 32 additions and 9 deletions
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41
js/MIDI/Plugin.js
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@ -264,6 +264,7 @@ if (window.Audio) (function () {
var volume = 127; // floating point
var channel_nid = -1; // current channel
var channels = []; // the audio channels
var channelInstrumentNoteIds = []; // instrumentId + noteId that is currently playing in each 'channel', for routing noteOff/chordOff calls
var notes = {}; // the piano keys
for (var nid = 0; nid < 12; nid++) {
channels[nid] = new Audio();
@ -272,18 +273,35 @@ if (window.Audio) (function () {
var playChannel = function (channel, note) {
if (!MIDI.channels[channel]) return;
var instrument = MIDI.channels[channel].instrument;
var id = MIDI.GeneralMIDI.byId[instrument].id;
var instrumentId = MIDI.GeneralMIDI.byId[instrument].id;
var note = notes[note];
if (!note) return;
var instrumentNoteId = instrumentId + "" + note.id;
var nid = (channel_nid + 1) % channels.length;
var time = (new Date()).getTime();
var audio = channels[nid];
audio.src = MIDI.Soundfont[id][note.id];
channelInstrumentNoteIds[ nid ] = instrumentNoteId;
audio.src = MIDI.Soundfont[instrumentId][note.id];
audio.volume = volume / 127;
audio.play();
channel_nid = nid;
};
var stopChannel = function (channel, note) {
if (!MIDI.channels[channel]) return;
var instrument = MIDI.channels[channel].instrument;
var instrumentId = MIDI.GeneralMIDI.byId[instrument].id;
var note = notes[note];
if (!note) return;
var instrumentNoteId = instrumentId + "" + note.id;
for(var i=0;i<channelInstrumentNoteIds.length;i++){
var cId = channelInstrumentNoteIds[i];
if(cId && cId == instrumentNoteId){
channels[i].pause();
}
}
};
root.programChange = function (channel, program) {
MIDI.channels[channel].instrument = program;
};
@ -305,9 +323,15 @@ if (window.Audio) (function () {
};
root.noteOff = function (channel, note, delay) {
setTimeout(function() {
channels[channel].pause();
}, delay * 1000)
var id = note2id[note];
if (!notes[id]) return;
if (delay) {
return setTimeout(function() {
stopChannel(channel, id);
}, delay * 1000)
} else {
stopChannel(channel, id);
}
};
root.chordOn = function (channel, chord, velocity, delay) {
@ -332,10 +356,10 @@ if (window.Audio) (function () {
if (!notes[id]) continue;
if (delay) {
return window.setTimeout(function () {
channels[channel].pause();
stopChannel(channel, id);
}, delay * 1000);
} else {
channels[channel].pause();
stopChannel(channel, id);
}
}
};
@ -347,7 +371,6 @@ if (window.Audio) (function () {
};
root.connect = function (conf) {
var loading = {};
for (var key in MIDI.keyToNote) {
note2id[MIDI.keyToNote[key]] = key;
notes[key] = {