public IEnumerable<NoteEvent> Convert(IEnumerable<Cell> cells)
{
NoteEvent lastNoteEvent = null;
int speed = 3;
foreach (var cell in cells)
{
if (cell.Event == null)
{
tick++;
continue;
}
ChannelEvent ce = cell.Event;
if (ce.Instrument != -1)
{
if (ce.Note == 0xFF) // nil, use current
{
if (lastNoteEvent != null && ce.Instrument == lastNoteEvent.Channel)
{
// volume may change
// ignore for now
// TODO
}
else
{
// if there's a note playing on currentInstrument
// stop it
// then start new note playing on ce.Instrument
if (lastNoteEvent != null && lastNoteEvent.Type == NoteEvent.EventType.NoteOn)
{
NoteEvent offEvent = lastNoteEvent.Clone(tick);
offEvent.Type = NoteEvent.EventType.NoteOff;
lastNoteEvent = offEvent;
yield return offEvent;
}
lastNoteEvent = new NoteEvent(tick, NoteEvent.EventType.NoteOn, ce.Instrument, GetNoteOffPitch(lastNoteEvent, ce), GetMissingVelocity(ce));
this[ce.ChannelNumber].Volume = lastNoteEvent.Velocity;
this[ce.ChannelNumber].Pitch = lastNoteEvent.Pitch;
yield return lastNoteEvent;
}
}
else if (ce.Note == 0xFE) // note off
{
lastNoteEvent = new NoteEvent(tick, NoteEvent.EventType.NoteOff, ce.Instrument, GetNoteOffPitch(lastNoteEvent, ce), GetMissingVelocity(ce));
this[ce.ChannelNumber].Volume = lastNoteEvent.Velocity;
this[ce.ChannelNumber].Pitch = lastNoteEvent.Pitch;
yield return lastNoteEvent;
}
else // note start
{
if (lastNoteEvent != null && lastNoteEvent.Type == NoteEvent.EventType.NoteOn)
{
NoteEvent offEvent = lastNoteEvent.Clone(tick);
offEvent.Type = NoteEvent.EventType.NoteOff;
lastNoteEvent = offEvent;
yield return offEvent;
}
lastNoteEvent = new NoteEvent(tick, NoteEvent.EventType.NoteOn, ce.Instrument, ChannelNoteToMidiPitch(ce.Note), GetMissingVelocity(ce));
this[ce.ChannelNumber].Volume = lastNoteEvent.Velocity;
this[ce.ChannelNumber].Pitch = lastNoteEvent.Pitch;
yield return lastNoteEvent;
}
}
tick += speed;
}
if (lastNoteEvent != null && lastNoteEvent.Type == NoteEvent.EventType.NoteOn)
{
NoteEvent offEvent = lastNoteEvent.Clone(tick);
offEvent.Type = NoteEvent.EventType.NoteOff;
lastNoteEvent = offEvent;
yield return offEvent;
}
}
private static NoteEvent GenerateNoteOnEvent(Channel channel, ChannelEvent channelEvent,int tick)
{
int volume = channelEvent.HasVolume ? channelEvent.Volume : channel.DefaultVolume;
channel.Instrument = channelEvent.HasInstrument ? channelEvent.Instrument : channel.Instrument;
NoteEvent noteOnEvent = new NoteEvent(tick, NoteEvent.EventType.NoteOn, channelEvent.Instrument, channelEvent.Note, volume);
channel.CurrentNote = noteOnEvent;
return noteOnEvent;
}
private int GetNoteOffPitch(NoteEvent lastNoteEvent, ChannelEvent ce)
{
if (lastNoteEvent == null)
{
return this[ce.ChannelNumber].Pitch;
}
return lastNoteEvent.Pitch;
}
