func midiListen(argv []*ell.Object) (*ell.Object, error) {
ch := ell.Null
midiMutex.Lock()
if midiIn != nil {
ch = ell.Channel(int(midiBufsize), "midi")
go func(s *portmidi.Stream, ch *ell.Object) {
for {
time.Sleep(10 * time.Millisecond)
events, err := s.Read(1024)
if err != nil {
continue
}
channel := ell.ChannelValue(ch)
if channel != nil {
for _, ev := range events {
ts := (float64(ev.Timestamp) / 1000) + midiBaseTime
st := ev.Status
d1 := ev.Data1
d2 := ev.Data2
channel <- ell.List(ell.Number(ts), ell.Number(float64(st)), ell.Number(float64(d1)), ell.Number(float64(d2)))
}
}
}
}(midiIn, ch)
}
midiMutex.Unlock()
return ch, nil
}
func midiInit() error {
ell.DefineFunctionKeyArgs("midi-open", midiOpen, ell.NullType,
[]*ell.Object{ell.StringType, ell.StringType, ell.NumberType},
[]*ell.Object{ell.EmptyString, ell.EmptyString, ell.Number(1024)},
[]*ell.Object{inputKey, outputKey, bufsizeKey})
ell.DefineFunction("midi-write", midiWrite, ell.NullType, ell.NumberType, ell.NumberType, ell.NumberType)
ell.DefineFunction("midi-close", midiClose, ell.NullType)
ell.DefineFunction("midi-listen", midiListen, ell.ChannelType)
return nil
}
func midiOpen(argv []*ell.Object) (*ell.Object, error) {
// defaultInput := "USB Oxygen 8 v2"
// defaultOutput := "IAC Driver Bus 1"
latency := int64(10)
if !midiOpened {
err := portmidi.Initialize()
if err != nil {
return nil, err
}
midiOpened = true
midiInDevice = ell.StringValue(argv[0])
midiOutDevice = ell.StringValue(argv[1])
midiBufsize = ell.Int64Value(argv[2])
outdev, outname := findMidiOutputDevice(midiOutDevice)
out, err := portmidi.NewOutputStream(outdev, midiBufsize, latency)
if err != nil {
return nil, err
}
midiOut = out
midiOutDevice = outname
if midiInDevice != "" {
indev := findMidiInputDevice(midiInDevice)
if indev >= 0 {
in, err := portmidi.NewInputStream(indev, midiBufsize)
if err != nil {
return nil, err
}
midiIn = in
}
}
midiBaseTime = ell.Now()
}
result := ell.MakeStruct(4)
if midiInDevice != "" {
ell.Put(result, inputKey, ell.String(midiInDevice))
}
if midiOutDevice != "" {
ell.Put(result, outputKey, ell.String(midiOutDevice))
}
ell.Put(result, bufsizeKey, ell.Number(float64(midiBufsize)))
return result, nil
}