97 lines
2.7 KiB
JavaScript
Executable File
97 lines
2.7 KiB
JavaScript
Executable File
var clone = function (o) {
|
|
if (typeof o != 'object') return (o);
|
|
if (o == null) return (o);
|
|
var ret = (typeof o.length == 'number') ? [] : {};
|
|
for (var key in o) ret[key] = clone(o[key]);
|
|
return ret;
|
|
};
|
|
|
|
function Replayer(midiFile, timeWarp, eventProcessor) {
|
|
var trackStates = [];
|
|
var beatsPerMinute = 120;
|
|
var ticksPerBeat = midiFile.header.ticksPerBeat;
|
|
|
|
for (var i = 0; i < midiFile.tracks.length; i++) {
|
|
trackStates[i] = {
|
|
'nextEventIndex': 0,
|
|
'ticksToNextEvent': (
|
|
midiFile.tracks[i].length ?
|
|
midiFile.tracks[i][0].deltaTime :
|
|
null
|
|
)
|
|
};
|
|
}
|
|
|
|
var nextEventInfo;
|
|
var samplesToNextEvent = 0;
|
|
|
|
function getNextEvent() {
|
|
var ticksToNextEvent = null;
|
|
var nextEventTrack = null;
|
|
var nextEventIndex = null;
|
|
|
|
for (var i = 0; i < trackStates.length; i++) {
|
|
if (
|
|
trackStates[i].ticksToNextEvent != null
|
|
&& (ticksToNextEvent == null || trackStates[i].ticksToNextEvent < ticksToNextEvent)
|
|
) {
|
|
ticksToNextEvent = trackStates[i].ticksToNextEvent;
|
|
nextEventTrack = i;
|
|
nextEventIndex = trackStates[i].nextEventIndex;
|
|
}
|
|
}
|
|
if (nextEventTrack != null) {
|
|
/* consume event from that track */
|
|
var nextEvent = midiFile.tracks[nextEventTrack][nextEventIndex];
|
|
if (midiFile.tracks[nextEventTrack][nextEventIndex + 1]) {
|
|
trackStates[nextEventTrack].ticksToNextEvent += midiFile.tracks[nextEventTrack][nextEventIndex + 1].deltaTime;
|
|
} else {
|
|
trackStates[nextEventTrack].ticksToNextEvent = null;
|
|
}
|
|
trackStates[nextEventTrack].nextEventIndex += 1;
|
|
/* advance timings on all tracks by ticksToNextEvent */
|
|
for (var i = 0; i < trackStates.length; i++) {
|
|
if (trackStates[i].ticksToNextEvent != null) {
|
|
trackStates[i].ticksToNextEvent -= ticksToNextEvent
|
|
}
|
|
}
|
|
return {
|
|
"ticksToEvent": ticksToNextEvent,
|
|
"event": nextEvent,
|
|
"track": nextEventTrack
|
|
}
|
|
} else {
|
|
return null;
|
|
}
|
|
};
|
|
//
|
|
var midiEvent;
|
|
var temporal = [];
|
|
//
|
|
function processEvents() {
|
|
function processNext() {
|
|
if ( midiEvent.event.type == "meta" && midiEvent.event.subtype == "setTempo" ) {
|
|
// tempo change events can occur anywhere in the middle and affect events that follow
|
|
beatsPerMinute = 60000000 / midiEvent.event.microsecondsPerBeat;
|
|
}
|
|
if (midiEvent.ticksToEvent > 0) {
|
|
var beatsToGenerate = midiEvent.ticksToEvent / ticksPerBeat;
|
|
var secondsToGenerate = beatsToGenerate / (beatsPerMinute / 60);
|
|
}
|
|
var time = (secondsToGenerate * 1000 * timeWarp) || 0;
|
|
temporal.push([ midiEvent, time]);
|
|
midiEvent = getNextEvent();
|
|
};
|
|
//
|
|
if (midiEvent = getNextEvent()) {
|
|
while(midiEvent) processNext(true);
|
|
}
|
|
};
|
|
processEvents();
|
|
return {
|
|
"getData": function() {
|
|
return clone(temporal);
|
|
}
|
|
};
|
|
};
|