feat: midi note input for the tracker

tracker/player.go

@@ -41,6 +41,11 @@ type (
 		BPM() (bpm float64, ok bool)
 	}
 
+	EventProcessor interface {
+		ProcessMessage(msg interface{})
+		ProcessEvent(event MIDINoteEvent)
+	}
+
 	// MIDINoteEvent is a MIDI event triggering or releasing a note. In
 	// processing, the Frame is relative to the start of the current buffer. In
 	// a Recording, the Frame is relative to the start of the recording.
@@ -89,9 +94,11 @@ const numRenderTries = 10000
 // model. context tells the player which MIDI events happen during the current
 // buffer. It is used to trigger and release notes during processing. The
 // context is also used to get the current BPM from the host.
-func (p *Player) Process(buffer sointu.AudioBuffer, context PlayerProcessContext) {
-	p.processMessages(context)
+func (p *Player) Process(buffer sointu.AudioBuffer, context PlayerProcessContext, ui EventProcessor) {
+	p.processMessages(context, ui)
+
 	midi, midiOk := context.NextEvent()
+
 	frame := 0
 
 	if p.recState == recStateRecording {
@@ -116,6 +123,10 @@ func (p *Player) Process(buffer sointu.AudioBuffer, context PlayerProcessContext
 			} else {
 				p.releaseInstrument(midi.Channel, midi.Note)
 			}
+			if ui != nil {
+				ui.ProcessEvent(midi)
+			}
+
 			midi, midiOk = context.NextEvent()
 		}
 		framesUntilMidi := len(buffer)
@@ -224,7 +235,7 @@ func (p *Player) advanceRow() {
 	p.rowtime = 0
 }
 
-func (p *Player) processMessages(context PlayerProcessContext) {
+func (p *Player) processMessages(context PlayerProcessContext, uiProcessor EventProcessor) {
 loop:
 	for { // process new message
 		select {
@@ -296,6 +307,9 @@ loop:
 			default:
 				// ignore unknown messages
 			}
+			if uiProcessor != nil {
+				uiProcessor.ProcessMessage(msg)
+			}
 		default:
 			break loop
 		}