static private MIDIMetaEvent ReadMetaEvent(int deltaTicks)
{
int metaEventType = ReadByte();
int dataLength = ReadVariableLengthInt();
switch (metaEventType)
{
case (int)MIDIMetaEventType.Tempo:
MIDITempoEvent tempoEvent = new MIDITempoEvent();
tempoEvent.deltaTicks = deltaTicks;
tempoEvent.tempo = ReadMultiByteInt((uint)dataLength);
tempoEvent.dataLength = dataLength;
return(tempoEvent);
case (int)MIDIMetaEventType.Time_Signature:
MIDITimeSignatureEvent timeSignatureEvent = new MIDITimeSignatureEvent();
timeSignatureEvent.deltaTicks = deltaTicks;
timeSignatureEvent.numerator = ReadByte();
timeSignatureEvent.denominator = (int)Mathf.Pow(2, ReadByte());
timeSignatureEvent.ticksPerMetronomeClick = ReadByte();
timeSignatureEvent.numberOf32ndNotesPerBeat = ReadByte();
timeSignatureEvent.dataLength = dataLength;
return(timeSignatureEvent);
case (int)MIDIMetaEventType.Key_Signature:
MIDIKeySignatureEvent keySignatureEvent = new MIDIKeySignatureEvent();
keySignatureEvent.deltaTicks = deltaTicks;
keySignatureEvent.key = ReadByte();
if (ReadByte() == 0)
{
keySignatureEvent.isMajor = true;
}
else
{
keySignatureEvent.isMajor = false;
}
keySignatureEvent.dataLength = dataLength;
return(keySignatureEvent);
default:
ReadBytes((uint)dataLength);
return(null);
}
}
static private void CalcEventTimestamps()
{
float elapsedTime = 0.0f;
float secondsPerTick = CalcSecondsPerTick(m_defaultMicrosecondsPerQuarterNote);
List <MIDIEvent> nextEventList = new List <MIDIEvent>();
foreach (MIDITrack track in m_song.tracks)
{
nextEventList.Add(track.events[0]);
}
MIDIEvent minNextEvent;
do
{
minNextEvent = FindMinNextEvent(nextEventList);
if (minNextEvent != null)
{
elapsedTime += secondsPerTick * minNextEvent.deltaTicks;
minNextEvent.timestamp = elapsedTime;
CorrectDeltaTicksOfNextEvents(minNextEvent, nextEventList);
ForwardMinNextEvent(minNextEvent, nextEventList);
// adjust tempo if respective event occurs
if (minNextEvent.GetType() == typeof(MIDITempoEvent))
{
MIDITempoEvent tempoEvent = minNextEvent as MIDITempoEvent;
secondsPerTick = CalcSecondsPerTick(tempoEvent.tempo);
}
}
}while (minNextEvent != null);
m_song.duration = elapsedTime;
}
static private void CalcMeasureTimestamps()
{
m_song.measureTimestamps = new List <float>();
// GetMetaEvents
List <MIDIEvent> metaEvents = new List <MIDIEvent>();
foreach (MIDITrack track in m_song.tracks)
{
foreach (MIDIEvent midiEvent in track.events)
{
if (midiEvent.GetType().IsSubclassOf(typeof(MIDIMetaEvent)))
{
metaEvents.Add(midiEvent);
}
}
}
// Sort MetaEvents by Timestamp
metaEvents.Sort(new MIDIEventComparer());
// calc timing metrics
float microsecondsPerQuarterNote = m_defaultMicrosecondsPerQuarterNote;
float beatsPerMeasure = 4.0f;
float beatNoteLength = 1.0f / 4.0f;
float quarterNotesPerBeat = 4.0f * beatNoteLength;
float secondsPerMeasure = CalcSecondsPerMeasure(microsecondsPerQuarterNote, quarterNotesPerBeat, beatsPerMeasure);
// iterate through measures
for (float elapsedTime = 0.0f; elapsedTime < m_song.duration + secondsPerMeasure; elapsedTime += secondsPerMeasure)
{
List <MIDIEvent> metaEventsToRemove = new List <MIDIEvent>();
foreach (MIDIEvent metaEvent in metaEvents)
{
if (metaEvent.timestamp <= elapsedTime)
{
if (metaEvent.GetType() == typeof(MIDITempoEvent))
{
MIDITempoEvent tempoEvent = metaEvent as MIDITempoEvent;
microsecondsPerQuarterNote = tempoEvent.tempo;
secondsPerMeasure = CalcSecondsPerMeasure(microsecondsPerQuarterNote, quarterNotesPerBeat, beatsPerMeasure);
}
else if (metaEvent.GetType() == typeof(MIDITimeSignatureEvent))
{
MIDITimeSignatureEvent timeSignatureEvent = metaEvent as MIDITimeSignatureEvent;
beatsPerMeasure = timeSignatureEvent.numerator;
beatNoteLength = 1.0f / timeSignatureEvent.denominator;
quarterNotesPerBeat = 4.0f * beatNoteLength;
secondsPerMeasure = CalcSecondsPerMeasure(microsecondsPerQuarterNote, quarterNotesPerBeat, beatsPerMeasure);
}
metaEventsToRemove.Add(metaEvent);
}
}
foreach (MIDIEvent metaEventToRemove in metaEventsToRemove)
{
metaEvents.Remove(metaEventToRemove);
}
m_song.measureTimestamps.Add(elapsedTime);
}
m_song.firstMeasureDuration = m_song.measureTimestamps[1] - m_song.measureTimestamps[0];
}
