private void HandleMidiNotesChanged(object sender, NotifyCollectionChangedEventArgs e)
{
IMidiNote[] itemsToRemove;
IMidiNote[] itemsToAdd;
lock (_voiceLock)
{
if (e.Action == NotifyCollectionChangedAction.Reset)
{
// itemsToRemove is everything that used to be in the list but is not in the list now
itemsToRemove =
_lastNoteList.Where(on => !FindMatchingVoices(on).Any()).ToArray();
// itemsToAdd is evertying that is in the list now that wasn't the list before
itemsToAdd = _midiSource.ActiveNotes.Where(on => !_lastNoteList.Any(an => an.Number == on.Number)).ToArray();
}
else
{
itemsToRemove = (e.OldItems ?? new IMidiNote[0]).OfType <IMidiNote>().ToArray();
itemsToAdd = (e.NewItems ?? new IMidiNote[0]).OfType <IMidiNote>().ToArray();
}
foreach (int i in Enumerable.Range(0, itemsToRemove.Length))
{
IMidiNote note = itemsToRemove[i];
IEnumerable <SimpleVoice> toKill = FindMatchingVoices(note);
toKill.Execute(KillNote);
}
foreach (IMidiNote note in itemsToAdd)
{
SimpleVoice voice = GetLowestPriorityVoice();
// this could only be null if there are zero voices, which is not allowed
if (voice == null)
{
throw new InvalidOperationException("No voices found.");
}
voice.FromMidiNote = note;
if (NumberOfVoices > 1 || !IsLegato)
{
voice.Intensity = 0;
}
SetPitch(voice);
if (!voice.IsActive || NumberOfVoices > 1 || !IsLegato)
{
voice.Intensity = note.Velocity;
}
voice.IsActive = true;
}
_lastNoteList = _midiSource.ActiveNotes;
}
}
private void SetPitch(SimpleVoice voice)
{
if (voice.FromMidiNote != null)
{
// TODO this search could be optimized
IScaleNote scaleNote = _scale.FirstOrDefault(n => n.MidiNoteNumber == voice.FromMidiNote.Number);
if (scaleNote != null)
{
voice.Pitch = scaleNote.Pitch + (Pitch.HalfStep * PitchBendRange * _midiSource.PitchBend);
}
}
}
public Guid?InjectNote(float pitch, float intensity)
{
SimpleVoice voice = GetLowestPriorityVoice();
voice.IsActive = false;
voice.FromMidiNote = null;
voice.Pitch = pitch;
voice.Intensity = intensity;
voice.Id = Guid.NewGuid();
return(voice.Id);
}
private void RemoveVoices()
{
lock (_voiceLock)
{
while (_voices.Count > _numberOfVoices)
{
SimpleVoice voice = GetLowestPriorityVoice();
if (voice != null)
{
voice.IsActive = false;
_voices.Remove(voice);
}
}
}
}
private void KillNote(SimpleVoice voice)
{
voice.FromMidiNote.PropertyChanged -= HandleMidiNotePropertyChanged;
voice.IsActive = false;
}
private SimpleVoice GetLowestPriorityVoice()
{
SimpleVoice lowestPriority = _voices.OrderBy(v => !v.IsActive).ThenBy(v => v.StartTime).FirstOrDefault();
return(lowestPriority);
}