feat: MIDI velocity, keyboard splits, and fixing instrument channel

Closes #124
Closes #215
Closes #221

CHANGELOG.md

@@ -5,6 +5,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 ### Added
+- MIDI velocity, keyboard splitting, forcing specific instrument to use
+  particular MIDI channel, and ability to transpose the incoming note values.
+  These settings can be configured under instrument properties. ([#124][i124],
+  [#215][i215], [#221][i221])
 - Ability to bind MIDI controllers to specific parameters. The MIDI menu has the
   options to bind/unbind parameters. When the user starts binding a parameter,
   Sointu waits for the next MIDI Control Change event and binds the currently
@@ -378,6 +382,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 [i120]: https://github.com/vsariola/sointu/issues/120
 [i121]: https://github.com/vsariola/sointu/issues/121
 [i122]: https://github.com/vsariola/sointu/issues/122
+[i124]: https://github.com/vsariola/sointu/issues/124
 [i125]: https://github.com/vsariola/sointu/issues/125
 [i128]: https://github.com/vsariola/sointu/issues/128
 [i129]: https://github.com/vsariola/sointu/issues/129
@@ -417,3 +422,5 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 [i200]: https://github.com/vsariola/sointu/issues/200
 [i210]: https://github.com/vsariola/sointu/issues/210
 [i211]: https://github.com/vsariola/sointu/issues/211
+[i215]: https://github.com/vsariola/sointu/issues/215
+[i221]: https://github.com/vsariola/sointu/issues/221

patch.go

@@ -24,7 +24,8 @@ type (
 		// ThreadMaskM1 is a bit mask of which threads are used, minus 1. Minus
 		// 1 is done so that the default value 0 means bit mask 0b0001 i.e. only
 		// thread 1 is rendering the instrument.
-		ThreadMaskM1 int `yaml:",omitempty"`
+		ThreadMaskM1 int  `yaml:",omitempty"`
+		MIDI         MIDI `yaml:",flow,omitempty"`
 		Units        []Unit
 	}
 
@@ -64,6 +65,16 @@ type (
 		Comment string `yaml:",omitempty"`
 	}
 
+	MIDI struct { // contains info on how MIDI events should trigger this instrument; if empty, then the instrument is not triggered by MIDI events
+		Channel       int  `yaml:",omitempty"` // 0 means automatically assigned channel, 1-16 means MIDI channel 1-16
+		Start         int  `yaml:",omitempty"` // MIDI note number to start on, 0-127
+		End           int  `yaml:",omitempty"` // MIDI note number to end on, counted backwards from 127, done so that the default number of 0 corresponds to "full keyboard", without any splittings
+		Transpose     int  `yaml:",omitempty"` // value to be added to the MIDI note/velocity number, can be negative
+		Velocity      bool `yaml:",omitempty"` // is this instrument triggered by midi event velocity or note
+		NoRetrigger   bool `yaml:",omitempty"` // if true, then this instrument does not retrigger if two consecutive events have the same value
+		IgnoreNoteOff bool `yaml:",omitempty"` // if true, then this instrument should ignore note off events, i.e. notes never release
+	}
+
 	ParamMap map[string]int
 
 	// UnitParameter documents one parameter that an unit takes

tracker/derived.go

@@ -2,6 +2,7 @@ package tracker
 
 import (
 	"fmt"
+	"strconv"
 	"time"
 
 	"github.com/vsariola/sointu"
@@ -45,6 +46,7 @@ type (
 		railWidth   int
 		params      [][]Parameter
 		paramsWidth int
+		title       string
 	}
 
 	derivedTrack struct {
@@ -72,6 +74,25 @@ func (m *Model) updateDeriveData(changeType ChangeType) {
 		m.updateParams()
 		m.updateRails()
 		m.updateWires()
+		m.buildInstrumentTitles()
+	}
+}
+
+func (m *Model) buildInstrumentTitles() {
+	m.midiAssign.update(m.d.Song.Patch)
+	for i, instr := range m.d.Song.Patch {
+		if i >= len(m.midiAssign.itoc) || m.midiAssign.itoc[i] == 0 {
+			m.derived.patch[i].title = "---"
+			continue
+		}
+		t := strconv.Itoa(m.midiAssign.itoc[i])
+		if instr.MIDI.Velocity {
+			t = t + " vel"
+		}
+		if instr.MIDI.Start > 0 || instr.MIDI.End > 0 {
+			t = t + fmt.Sprintf(" [%d-%d]", instr.MIDI.Start, 127-instr.MIDI.End)
+		}
+		m.derived.patch[i].title = t
 	}
 }
 

tracker/gioui/instrument_properties.go

@@ -27,6 +27,14 @@ type (
 		voices              *NumericUpDownState
 		splitInstrumentBtn  *Clickable
 		splitInstrumentHint string
+
+		ignoreNoteOff *Clickable
+		velocity      *Clickable
+		change        *Clickable
+		noteStart     *NumericUpDownState
+		noteEnd       *NumericUpDownState
+		transpose     *NumericUpDownState
+		midiChannel   *NumericUpDownState
 	}
 )
 
@@ -40,6 +48,13 @@ func NewInstrumentProperties() *InstrumentProperties {
 		voices:             NewNumericUpDownState(),
 		splitInstrumentBtn: new(Clickable),
 		threadBtns:         [4]*Clickable{new(Clickable), new(Clickable), new(Clickable), new(Clickable)},
+		ignoreNoteOff:      new(Clickable),
+		velocity:           new(Clickable),
+		change:             new(Clickable),
+		noteStart:          NewNumericUpDownState(),
+		noteEnd:            NewNumericUpDownState(),
+		transpose:          NewNumericUpDownState(),
+		midiChannel:        NewNumericUpDownState(),
 	}
 	ret.soloHint = makeHint("Solo", " (%s)", "SoloToggle")
 	ret.unsoloHint = makeHint("Unsolo", " (%s)", "SoloToggle")
@@ -81,8 +96,9 @@ func (ip *InstrumentProperties) layout(gtx C) D {
 			layout.Rigid(thread4btn.Layout),
 		)
 	}
-
-	return ip.list.Layout(gtx, 11, func(gtx C, index int) D {
+	gtx.Constraints.Max.X = min(gtx.Dp(300), gtx.Constraints.Max.X)
+	gtx.Constraints.Min.X = min(gtx.Constraints.Max.X, gtx.Constraints.Min.X)
+	return ip.list.Layout(gtx, 18, func(gtx C, index int) D {
 		switch index {
 		case 0:
 			return layoutInstrumentPropertyLine(gtx, "Name", func(gtx C) D {
@@ -93,12 +109,42 @@ func (ip *InstrumentProperties) layout(gtx C) D {
 		case 4:
 			muteBtn := ToggleIconBtn(tr.Instrument().Mute(), tr.Theme, ip.muteBtn, icons.ToggleCheckBoxOutlineBlank, icons.ToggleCheckBox, ip.muteHint, ip.unmuteHint)
 			return layoutInstrumentPropertyLine(gtx, "Mute", muteBtn.Layout)
-		case 6:
+		case 5:
 			soloBtn := ToggleIconBtn(tr.Instrument().Solo(), tr.Theme, ip.soloBtn, icons.ToggleCheckBoxOutlineBlank, icons.ToggleCheckBox, ip.soloHint, ip.unsoloHint)
 			return layoutInstrumentPropertyLine(gtx, "Solo", soloBtn.Layout)
-		case 8:
+		case 7:
 			return layoutInstrumentPropertyLine(gtx, "Thread", threadbtnline)
+		case 9:
+			l := Label(tr.Theme, &tr.Theme.InstrumentEditor.Properties.Label, "MIDI")
+			l.Alignment = text.Middle
+			return l.Layout(gtx)
 		case 10:
+			channelLine := NumUpDown(tr.MIDI().Channel(), tr.Theme, ip.midiChannel, "0 = automatic")
+			return layoutInstrumentPropertyLine(gtx, "Channel", channelLine.Layout)
+		case 11:
+			start := NumUpDown(tr.MIDI().NoteStart(), tr.Theme, ip.noteStart, "Lowest note triggering\nthis instrument")
+			end := NumUpDown(tr.MIDI().NoteEnd(), tr.Theme, ip.noteEnd, "Highest note triggering\nthis instrument")
+			noteRangeLine := func(gtx C) D {
+				return layout.Flex{}.Layout(gtx,
+					layout.Rigid(start.Layout),
+					layout.Rigid(layout.Spacer{Width: 6}.Layout),
+					layout.Rigid(end.Layout),
+				)
+			}
+			return layoutInstrumentPropertyLine(gtx, "Note range", noteRangeLine)
+		case 12:
+			transpose := NumUpDown(tr.MIDI().Transpose(), tr.Theme, ip.transpose, "Transpose of the MIDI values")
+			return layoutInstrumentPropertyLine(gtx, "Transpose", transpose.Layout)
+		case 13:
+			velocityBtn := ToggleIconBtn(tr.MIDI().Velocity(), tr.Theme, ip.velocity, icons.ToggleCheckBoxOutlineBlank, icons.ToggleCheckBox, "Instrument triggered by\nMIDI note", "Instrument triggered by\nMIDI velocity")
+			return layoutInstrumentPropertyLine(gtx, "Velocity", velocityBtn.Layout)
+		case 14:
+			retriggerBtn := ToggleIconBtn(tr.MIDI().Change(), tr.Theme, ip.change, icons.ToggleCheckBoxOutlineBlank, icons.ToggleCheckBox, "Every note/velocity retriggers", "Retrigger only when\nnote/velocity changes")
+			return layoutInstrumentPropertyLine(gtx, "No retrigger", retriggerBtn.Layout)
+		case 15:
+			noteOff := ToggleIconBtn(tr.MIDI().IgnoreNoteOff(), tr.Theme, ip.ignoreNoteOff, icons.ToggleCheckBoxOutlineBlank, icons.ToggleCheckBox, "Notes released", "Notes never released")
+			return layoutInstrumentPropertyLine(gtx, "Ignore note off", noteOff.Layout)
+		case 17:
 			return layout.UniformInset(unit.Dp(6)).Layout(gtx, func(gtx C) D {
 				return ip.commentEditor.Layout(gtx, tr.Instrument().Comment(), tr.Theme, &tr.Theme.InstrumentEditor.InstrumentComment, "Comment")
 			})
@@ -112,7 +158,6 @@ func (ip *InstrumentProperties) layout(gtx C) D {
 
 func layoutInstrumentPropertyLine(gtx C, text string, content layout.Widget) D {
 	tr := TrackerFromContext(gtx)
-	gtx.Constraints.Max.X = min(gtx.Dp(300), gtx.Constraints.Max.X)
 	label := Label(tr.Theme, &tr.Theme.InstrumentEditor.Properties.Label, text)
 	return layout.Flex{Axis: layout.Horizontal, Alignment: layout.Middle}.Layout(gtx,
 		layout.Rigid(layout.Spacer{Width: 6, Height: 36}.Layout),

tracker/gioui/patch_panel.go

@@ -5,7 +5,6 @@ import (
 	"image"
 	"image/color"
 	"io"
-	"strconv"
 
 	"gioui.org/io/clipboard"
 	"gioui.org/io/event"
@@ -251,9 +250,9 @@ func (il *InstrumentList) Layout(gtx C) D {
 	gtx.Constraints.Max.Y = gtx.Dp(36)
 	gtx.Constraints.Min.Y = gtx.Dp(36)
 	element := func(gtx C, i int) D {
-		grabhandle := Label(t.Theme, &t.Theme.InstrumentEditor.InstrumentList.Number, strconv.Itoa(i+1))
+		name, title, level, mute, ok := t.Instrument().Item(i)
+		grabhandle := Label(t.Theme, &t.Theme.InstrumentEditor.InstrumentList.Number, title)
 		label := func(gtx C) D {
-			name, level, mute, ok := t.Instrument().Item(i)
 			if !ok {
 				labelStyle := Label(t.Theme, &t.Theme.InstrumentEditor.InstrumentList.Number, "")
 				return layout.Center.Layout(gtx, labelStyle.Layout)

tracker/instrument.go

@@ -75,9 +75,9 @@ func (m *splitInstrument) Do() {
 }
 
 // Item returns information about the instrument at a given index.
-func (v *InstrModel) Item(i int) (name string, maxLevel float32, mute bool, ok bool) {
+func (v *InstrModel) Item(i int) (name, title string, maxLevel float32, mute bool, ok bool) {
 	if i < 0 || i >= len(v.d.Song.Patch) {
-		return "", 0, false, false
+		return "", "", 0, false, false
 	}
 	name = v.d.Song.Patch[i].Name
 	mute = v.d.Song.Patch[i].Mute
@@ -93,6 +93,9 @@ func (v *InstrModel) Item(i int) (name string, maxLevel float32, mute bool, ok b
 			}
 		}
 	}
+	if i >= 0 && i < len(v.derived.patch) {
+		title = v.derived.patch[i].title
+	}
 	ok = true
 	return
 }
@@ -478,6 +481,7 @@ success:
 	}
 	instrument.NumVoices = clamp(instrument.NumVoices, 1, 32-numVoices)
 	(*Model)(m).assignUnitIDs(instrument.Units)
+	instrument.MIDI = m.d.Song.Patch[m.d.InstrIndex].MIDI // keep the MIDI config of the current instrument
 	m.d.Song.Patch[m.d.InstrIndex] = instrument
 	return true
 }

tracker/midi.go

@@ -3,6 +3,8 @@ package tracker
 import (
 	"encoding/json"
 	"fmt"
+
+	"github.com/vsariola/sointu"
 )
 
 type MIDIModel Model
@@ -144,6 +146,239 @@ func (m *midiInputtingNotes) SetValue(val bool) {
 	TrySend(m.broker.ToPlayer, any(m.midi.router))
 }
 
+// Transpose returns an Int controlling the MIDI transpose value of the
+// currently selected instrument.
+func (m *MIDIModel) Transpose() Int { return MakeInt((*midiTranspose)(m)) }
+
+type midiTranspose MIDIModel
+
+func (m *midiTranspose) Value() int {
+	i := m.d.InstrIndex
+	if i < 0 || i >= len(m.d.Song.Patch) {
+		return 0
+	}
+	return m.d.Song.Patch[i].MIDI.Transpose
+}
+func (m *midiTranspose) SetValue(val int) bool {
+	i := m.d.InstrIndex
+	if i < 0 || i >= len(m.d.Song.Patch) {
+		return false
+	}
+	defer (*Model)(m).change("MIDITranspose", PatchChange, MinorChange)()
+	m.d.Song.Patch[i].MIDI.Transpose = val
+	return true
+}
+func (m *midiTranspose) Range() RangeInclusive { return RangeInclusive{-127, 127} }
+
+// NoteStart returns an Int controlling the MIDI note start value of the
+// currently selected instrument.
+func (m *MIDIModel) NoteStart() Int { return MakeInt((*midiNoteStart)(m)) }
+
+type midiNoteStart MIDIModel
+
+func (m *midiNoteStart) Value() int {
+	i := m.d.InstrIndex
+	if i < 0 || i >= len(m.d.Song.Patch) {
+		return 0
+	}
+	return m.d.Song.Patch[i].MIDI.Start
+}
+func (m *midiNoteStart) SetValue(val int) bool {
+	i := m.d.InstrIndex
+	if i < 0 || i >= len(m.d.Song.Patch) {
+		return false
+	}
+	defer (*Model)(m).change("MIDINoteStart", PatchChange, MinorChange)()
+	m.d.Song.Patch[i].MIDI.Start = val
+	return true
+}
+func (m *midiNoteStart) Range() RangeInclusive { return RangeInclusive{0, 127} }
+
+// NoteEnd returns an Int controlling the MIDI note end value of the
+// currently selected instrument.
+func (m *MIDIModel) NoteEnd() Int { return MakeInt((*midiNoteEnd)(m)) }
+
+type midiNoteEnd MIDIModel
+
+func (m *midiNoteEnd) Value() int {
+	i := m.d.InstrIndex
+	if i < 0 || i >= len(m.d.Song.Patch) {
+		return 0
+	}
+	return 127 - m.d.Song.Patch[i].MIDI.End
+}
+func (m *midiNoteEnd) SetValue(val int) bool {
+	i := m.d.InstrIndex
+	if i < 0 || i >= len(m.d.Song.Patch) {
+		return false
+	}
+	defer (*Model)(m).change("MIDINoteEnd", PatchChange, MinorChange)()
+	m.d.Song.Patch[i].MIDI.End = 127 - val
+	return true
+}
+func (m *midiNoteEnd) Range() RangeInclusive { return RangeInclusive{0, 127} }
+
+// Velocity returns a Bool controlling whether the velocity value from MIDI
+// event is used instead of the normal note value
+func (m *MIDIModel) Velocity() Bool { return MakeBool((*midiVelocity)(m)) }
+
+type midiVelocity MIDIModel
+
+func (m *midiVelocity) Value() bool {
+	i := m.d.InstrIndex
+	if i < 0 || i >= len(m.d.Song.Patch) {
+		return false
+	}
+	return m.d.Song.Patch[i].MIDI.Velocity
+}
+func (m *midiVelocity) SetValue(val bool) {
+	i := m.d.InstrIndex
+	if i < 0 || i >= len(m.d.Song.Patch) {
+		return
+	}
+	defer (*Model)(m).change("MIDIVelocity", PatchChange, MinorChange)()
+	m.d.Song.Patch[i].MIDI.Velocity = val
+}
+
+// Change returns a Bool controlling whether only the change in note or velocity value is used
+func (m *MIDIModel) Change() Bool { return MakeBool((*midiChange)(m)) }
+
+type midiChange MIDIModel
+
+func (m *midiChange) Value() bool {
+	i := m.d.InstrIndex
+	if i < 0 || i >= len(m.d.Song.Patch) {
+		return false
+	}
+	return m.d.Song.Patch[i].MIDI.NoRetrigger
+}
+func (m *midiChange) SetValue(val bool) {
+	i := m.d.InstrIndex
+	if i < 0 || i >= len(m.d.Song.Patch) {
+		return
+	}
+	defer (*Model)(m).change("MIDIChange", PatchChange, MinorChange)()
+	m.d.Song.Patch[i].MIDI.NoRetrigger = val
+}
+
+// IgnoreNoteOff returns a Bool controlling whether note off events are ignored
+func (m *MIDIModel) IgnoreNoteOff() Bool { return MakeBool((*midiIgnoreNoteOff)(m)) }
+
+type midiIgnoreNoteOff MIDIModel
+
+func (m *midiIgnoreNoteOff) Value() bool {
+	i := m.d.InstrIndex
+	if i < 0 || i >= len(m.d.Song.Patch) {
+		return false
+	}
+	return m.d.Song.Patch[i].MIDI.IgnoreNoteOff
+}
+func (m *midiIgnoreNoteOff) SetValue(val bool) {
+	i := m.d.InstrIndex
+	if i < 0 || i >= len(m.d.Song.Patch) {
+		return
+	}
+	defer (*Model)(m).change("MIDIIgnoreNoteOff", PatchChange, MinorChange)()
+	m.d.Song.Patch[i].MIDI.IgnoreNoteOff = val
+}
+
+// Channel returns an Int controlling the MIDI channel of the currently selected
+// instrument. 0 = automatically selected, 1-16 fixed to specific MIDI channel
+func (m *MIDIModel) Channel() Int { return MakeInt((*midiChannel)(m)) }
+
+type midiChannel MIDIModel
+
+func (m *midiChannel) Value() int {
+	i := m.d.InstrIndex
+	if i < 0 || i >= len(m.d.Song.Patch) {
+		return 0
+	}
+	return m.d.Song.Patch[i].MIDI.Channel
+}
+func (m *midiChannel) SetValue(val int) bool {
+	i := m.d.InstrIndex
+	if i < 0 || i >= len(m.d.Song.Patch) {
+		return false
+	}
+	defer (*Model)(m).change("MIDIChannel", PatchChange, MinorChange)()
+	m.d.Song.Patch[i].MIDI.Channel = val
+	return true
+}
+func (m *midiChannel) Range() RangeInclusive { return RangeInclusive{0, 16} }
+
+type (
+	midiAssigns struct {
+		ctoi map[midiAssignKey][]midiAssignRange // map to quickly find which instruments to trigger
+		itoc []int                               // slice to quickly find which MIDI channel was assigned for a given instrument
+	}
+	midiAssignKey struct {
+		Channel  int
+		Velocity bool
+	}
+	midiAssignRange struct {
+		Start, End byte
+		Instr      int
+	}
+)
+
+const MAX_MIDI_CHANNELS = 16
+
+// update tries to assign MIDI channels to instruments that have MIDI channel 0
+// (automatic) in a way that minimizes the number of channels used. It also
+// updates the ctoi and itoc maps for quick lookup when routing MIDI messages.
+// The algorithm iterates through the instruments and, for those with automatic
+// channel, it tries to find the lowest MIDI channel that doesn't have an
+// overlapping note range with any of the already assigned instruments with the
+// same velocity setting. If it runs out of channels, it leaves the rest of the
+// instruments unassigned (channel 0).
+func (a *midiAssigns) update(p sointu.Patch) {
+	for k := range a.ctoi {
+		a.ctoi[k] = a.ctoi[k][:0] // clear all slices, keeping their allocated memory
+	}
+	a.itoc = a.itoc[:0]
+	for i, instr := range p {
+		if instr.MIDI.Channel != 0 {
+			k := midiAssignKey{Channel: instr.MIDI.Channel, Velocity: instr.MIDI.Velocity}
+			v := midiAssignRange{Start: byte(max(instr.MIDI.Start, 0)), End: byte(min(127-instr.MIDI.End, 127)), Instr: i}
+			a.ctoi[k] = append(a.ctoi[k], v)
+		}
+	}
+	k := midiAssignKey{Channel: 1, Velocity: false}
+outer:
+	for i, e := range p {
+		if e.MIDI.Channel > 0 { // already assigned to a specific channel, so skip automatic assignment
+			a.itoc = append(a.itoc, e.MIDI.Channel)
+			continue
+		}
+		k.Velocity = e.MIDI.Velocity
+		x := midiAssignRange{Start: byte(max(e.MIDI.Start, 0)), End: byte(min(127-e.MIDI.End, 127)), Instr: i}
+	inner:
+		for {
+			for _, y := range a.ctoi[k] {
+				if max(x.Start, y.Start) <= min(x.End, y.End) {
+					if k.Channel >= MAX_MIDI_CHANNELS {
+						break outer // we've ran out of channels, leave the rest unassigned
+					}
+					k.Channel++
+					continue inner // this channel is already taken for the overlapping range, try next channel
+				}
+			}
+			break // this channel had no overlaps with the already assigned ranges, so we can use it
+		}
+		a.ctoi[k] = append(a.ctoi[k], x)
+		a.itoc = append(a.itoc, k.Channel)
+	}
+}
+
+func (a *midiAssigns) forEach(chn int, vel bool, val byte, cb func(instr int, val byte)) {
+	k := midiAssignKey{Channel: chn, Velocity: vel}
+	for _, r := range a.ctoi[k] {
+		if r.Start <= val && val <= r.End {
+			cb(r.Instr, val)
+		}
+	}
+}
+
 // MIDIMessage represents a MIDI message received from a MIDI input port or VST
 // host.
 type MIDIMessage struct {

tracker/model.go

@@ -90,7 +90,8 @@ type (
 
 		broker *Broker
 
-		midi midiState
+		midi       midiState
+		midiAssign midiAssigns
 
 		presetData presetData
 	}
@@ -177,6 +178,7 @@ func NewModel(broker *Broker, synthers []sointu.Synther, midiContext MIDIContext
 	m := new(Model)
 	m.synthers = synthers
 	m.midi = midiState{context: midiContext}
+	m.midiAssign = midiAssigns{ctoi: map[midiAssignKey][]midiAssignRange{}}
 	m.broker = broker
 	m.d.Octave = 4
 	m.linkInstrTrack = true

tracker/player.go

@@ -30,7 +30,9 @@ type (
 		frameDeltas map[any]int64 // Player.frame (approx.)= event.Timestamp + frameDeltas[event.Source]
 		events      NoteEventList
 
-		midiRouter midiRouter
+		midiRouter  midiRouter
+		midiAssigns midiAssigns
+		prevVal     []byte
 
 		status PlayerStatus // the part of the Player state that is communicated to the model to visualize what Player is doing
 
@@ -64,7 +66,7 @@ type (
 	NoteEvent struct {
 		Timestamp int64 // in frames, relative to whatever clock the source is using
 		On        bool
-		Channel   int
+		Channel   int // which track or instrument is triggered, depending on IsTrack
 		Note      byte
 		IsTrack   bool // true if "Channel" means track number, false if it means instrument number
 		Source    any
@@ -90,6 +92,7 @@ func NewPlayer(broker *Broker, synther sointu.Synther) *Player {
 		broker:      broker,
 		synther:     synther,
 		frameDeltas: make(map[any]int64),
+		midiAssigns: midiAssigns{ctoi: map[midiAssignKey][]midiAssignRange{}},
 	}
 }
 
@@ -183,6 +186,7 @@ func (p *Player) destroySynth() {
 		p.synth.Close()
 		p.synth = nil
 	}
+	p.prevVal = p.prevVal[:0]
 }
 
 func (p *Player) advanceRow() {
@@ -281,16 +285,31 @@ loop:
 			case *NoteEvent:
 				p.events = append(p.events, *m)
 			case *MIDIMessage:
-				// In future, here we should map midi channels to various
-				// instruments, possible mapping the velocity to another
-				// instrument as well
 				if m.Data[0] >= 0x80 && m.Data[0] <= 0x9F {
-					p.events = append(p.events, NoteEvent{
-						Timestamp: m.Timestamp,
-						Channel:   int(m.Data[0] & 0x0F),
-						Note:      m.Data[1],
-						On:        m.Data[0] >= 0x90,
-						Source:    m.Source})
+					chn := int(m.Data[0]&0x0F) + 1
+					note := m.Data[1]
+					velocity := m.Data[2]
+					on := m.Data[0] >= 0x90
+					cb := func(i int, v byte) {
+						if i < 0 || i >= len(p.song.Patch) {
+							return
+						}
+						instr := p.song.Patch[i]
+						if instr.MIDI.IgnoreNoteOff && !on {
+							return // instruments configured to ignore note offs never release
+						}
+						n := byte(min(max(int(v)+instr.MIDI.Transpose, 2), 255)) // 0 and 1 have special meaning
+						if instr.MIDI.NoRetrigger && on && i < len(p.prevVal) && p.prevVal[i] == n {
+							return // the instrument is configured to respond only to changes in values and there was no change
+						}
+						p.events = append(p.events, NoteEvent{Timestamp: m.Timestamp, Channel: i, Note: n, On: on, Source: m.Source})
+						for len(p.prevVal) <= i {
+							p.prevVal = append(p.prevVal, 0)
+						}
+						p.prevVal[i] = n
+					}
+					p.midiAssigns.forEach(chn, false, note, cb)    // trigger instruments that are configured to respond to this midi channel's note events
+					p.midiAssigns.forEach(chn, true, velocity, cb) // trigger instruments that are configured to respond to this midi channel's velocity events
 				}
 			case midiRouter:
 				p.midiRouter = m
@@ -401,6 +420,7 @@ func (p *Player) compileOrUpdateSynth() {
 		}
 		voice += instr.NumVoices
 	}
+	p.midiAssigns.update(p.song.Patch)
 }
 
 // all sendTargets from player are always non-blocking, to ensure that the player thread cannot end up in a dead-lock

tracker/presets.go

@@ -167,6 +167,7 @@ func (m *presetResultList) SetSelected(i int) {
 	newInstr := m.presetData.cache.results[i].instr.Copy()
 	newInstr.NumVoices = clamp(m.d.Song.Patch[m.d.InstrIndex].NumVoices, 1, vm.MAX_VOICES)
 	(*Model)(m).assignUnitIDs(newInstr.Units)
+	newInstr.MIDI = m.d.Song.Patch[m.d.InstrIndex].MIDI // keep the MIDI config of the current instrument
 	m.d.Song.Patch[m.d.InstrIndex] = newInstr
 }
 

tracker/recording.go

@@ -175,7 +175,7 @@ func (recording *Recording) Score(patch sointu.Patch, rowsPerBeat, rowsPerPatter
 				order[k] = len(patterns)
 				patterns = append(patterns, newPat)
 			}
-			track := sointu.Track{NumVoices: numVoices, Effect: false, Order: order, Patterns: patterns}
+			track := sointu.Track{NumVoices: numVoices, Effect: patch[i].MIDI.Velocity, Order: order, Patterns: patterns}
 			songTracks = append(songTracks, track)
 		}
 	}