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var soundsCache = require('./sounds-cache');
var pitchToNoteName = require('./pitch-to-note-name');
var centsToFactor = require("./cents-to-factor");
function placeNote(outputAudioBuffer, sampleRate, sound, startArray, volumeMultiplier, ofsMs, fadeTimeSec, noteEndSec, debugCallback) {
// sound contains { instrument, pitch, volume, len, pan, tempoMultiplier
// len is in whole notes. Multiply by tempoMultiplier to get seconds.
// ofsMs is an offset to subtract from the note to line up programs that have different length onsets.
var OfflineAC = window.OfflineAudioContext ||
window.webkitOfflineAudioContext;
var len = sound.len * sound.tempoMultiplier;
if (ofsMs)
len +=ofsMs/1000;
len -= noteEndSec;
if (len < 0)
len = 0.005; // Have some small audible length no matter how short the note is.
var offlineCtx = new OfflineAC(2,Math.floor((len+fadeTimeSec)*sampleRate),sampleRate);
var noteName = pitchToNoteName[sound.pitch];
if (!soundsCache[sound.instrument]) {
// It shouldn't happen that the entire instrument cache wasn't created, but this has been seen in practice, so guard against it.
if (debugCallback)
debugCallback('placeNote skipped (instrument empty): '+sound.instrument+':'+noteName)
return Promise.resolve();
}
var noteBufferPromise = soundsCache[sound.instrument][noteName];
if (!noteBufferPromise) {
// if the note isn't present then just skip it - it will leave a blank spot in the audio.
if (debugCallback)
debugCallback('placeNote skipped: '+sound.instrument+':'+noteName)
return Promise.resolve();
}
return noteBufferPromise
.then(function (response) {
// create audio buffer
var source = offlineCtx.createBufferSource();
source.buffer = response.audioBuffer;
// add gain
// volume can be between 1 to 127. This translation to gain is just trial and error.
// The smaller the first number, the more dynamic range between the quietest to loudest.
// The larger the second number, the louder it will be in general.
var volume = (sound.volume / 96) * volumeMultiplier;
source.gainNode = offlineCtx.createGain();
// add pan if supported and present
if (sound.pan && offlineCtx.createStereoPanner) {
source.panNode = offlineCtx.createStereoPanner();
source.panNode.pan.setValueAtTime(sound.pan, 0);
}
source.gainNode.gain.value = volume; // Math.min(2, Math.max(0, volume));
source.gainNode.gain.linearRampToValueAtTime(source.gainNode.gain.value, len);
source.gainNode.gain.linearRampToValueAtTime(0.0, len + fadeTimeSec);
if (sound.cents) {
source.playbackRate.value = centsToFactor(sound.cents);
}
// connect all the nodes
if (source.panNode) {
source.panNode.connect(offlineCtx.destination);
source.gainNode.connect(source.panNode);
} else {
source.gainNode.connect(offlineCtx.destination);
}
source.connect(source.gainNode);
// Do the process of creating the sound and placing it in the buffer
source.start(0);
if (source.noteOff) {
source.noteOff(len + fadeTimeSec);
} else {
source.stop(len + fadeTimeSec);
}
var fnResolve;
offlineCtx.oncomplete = function(e) {
if (e.renderedBuffer && e.renderedBuffer.getChannelData) { // If the system gets overloaded or there are network problems then this can start failing. Just drop the note if so.
for (var i = 0; i < startArray.length; i++) {
//Math.floor(startArray[i] * sound.tempoMultiplier * sampleRate)
var start = startArray[i] * sound.tempoMultiplier;
if (ofsMs)
start -=ofsMs/1000;
if (start < 0)
start = 0; // If the item that is moved back is at the very beginning of the buffer then don't move it back. To do that would be to push everything else forward. TODO-PER: this should probably be done at some point but then it would change timing in existing apps.
start = Math.floor(start*sampleRate);
copyToChannel(outputAudioBuffer, e.renderedBuffer, start);
}
}
if (debugCallback)
debugCallback('placeNote: '+sound.instrument+':'+noteName)
fnResolve();
};
offlineCtx.startRendering();
return new Promise(function(resolve) {
fnResolve = resolve;
});
})
.catch(function (error) {
if (debugCallback)
debugCallback('placeNote catch: '+error.message)
return Promise.resolve()
});
}
var copyToChannel = function(toBuffer, fromBuffer, start) {
for (var ch = 0; ch < 2; ch++) {
var fromData = fromBuffer.getChannelData(ch);
var toData = toBuffer.getChannelData(ch);
// Mix the current note into the existing track
for (var n = 0; n < fromData.length; n++) {
toData[n + start] += fromData[n];
}
}
};
module.exports = placeNote;
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