feat: add ability to import 4klang patches and instruments

4klang.go

@@ -0,0 +1,519 @@
+package sointu
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"io"
+)
+
+func Read4klangPatch(r io.Reader) (patch Patch, err error) {
+	var versionTag uint32
+	var version int
+	var polyphonyUint32 uint32
+	var polyphony int
+	var instrumentNames [_4KLANG_MAX_INSTRS]string
+	patch = make(Patch, 0)
+	if err := binary.Read(r, binary.LittleEndian, &versionTag); err != nil {
+		return nil, fmt.Errorf("binary.Read: %w", err)
+	}
+	var ok bool
+	if version, ok = _4klangVersionTags[versionTag]; !ok {
+		return nil, fmt.Errorf("unknown 4klang version tag: %d", versionTag)
+	}
+	if err := binary.Read(r, binary.LittleEndian, &polyphonyUint32); err != nil {
+		return nil, fmt.Errorf("binary.Read: %w", err)
+	}
+	polyphony = int(polyphonyUint32)
+	if polyphony < 1 {
+		polyphony = 1
+	}
+	for i := range instrumentNames {
+		instrumentNames[i], err = read4klangName(r)
+		if err != nil {
+			return nil, fmt.Errorf("read4klangName: %w", err)
+		}
+	}
+	m := make(_4klangTargetMap)
+	id := 1
+	for instrIndex := 0; instrIndex < _4KLANG_MAX_INSTRS; instrIndex++ {
+		var units []Unit
+		if units, err = read4klangUnits(r, version, instrIndex, m, &id); err != nil {
+			return nil, fmt.Errorf("read4klangUnits: %w", err)
+		}
+		if len(units) > 0 {
+			patch = append(patch, Instrument{Name: instrumentNames[instrIndex], NumVoices: polyphony, Units: units})
+		}
+	}
+	var units []Unit
+	if units, err = read4klangUnits(r, version, _4KLANG_MAX_INSTRS, m, &id); err != nil {
+		return nil, fmt.Errorf("read4klangUnits: %w", err)
+	}
+	if len(units) > 0 {
+		patch = append(patch, Instrument{Name: "Global", NumVoices: 1, Units: units})
+	}
+	for i, instr := range patch {
+		fix4klangTargets(i, instr, m)
+	}
+	return
+}
+
+func Read4klangInstrument(r io.Reader) (instr Instrument, err error) {
+	var versionTag uint32
+	var version int
+	var name string
+	if err := binary.Read(r, binary.LittleEndian, &versionTag); err != nil {
+		return Instrument{}, fmt.Errorf("binary.Read: %w", err)
+	}
+	var ok bool
+	if version, ok = _4klangVersionTags[versionTag]; !ok {
+		return Instrument{}, fmt.Errorf("unknown 4klang version tag: %d", versionTag)
+	}
+	if name, err = read4klangName(r); err != nil {
+		return Instrument{}, fmt.Errorf("read4klangName: %w", err)
+	}
+	var units []Unit
+	id := 1
+	m := make(_4klangTargetMap)
+	if units, err = read4klangUnits(r, version, 0, m, &id); err != nil {
+		return Instrument{}, fmt.Errorf("read4klangUnits: %w", err)
+	}
+	ret := Instrument{Name: name, NumVoices: 1, Units: units}
+	fix4klangTargets(0, ret, m)
+	return ret, nil
+}
+
+type (
+	_4klangStackUnit struct {
+		stack, unit int
+	}
+
+	_4klangTargetMap map[_4klangStackUnit]int
+
+	_4klangPorts struct {
+		UnitType string
+		PortName [8]string
+	}
+)
+
+const (
+	_4KLANG_MAX_INSTRS   = 16
+	_4KLANG_MAX_UNITS    = 64
+	_4KLANG_MAX_SLOTS    = 16
+	_4KLANG_MAX_NAME_LEN = 64
+)
+
+var (
+	_4klangVersionTags map[uint32]int = map[uint32]int{
+		0x31316b34: 11, // 4k11
+		0x32316b34: 12, // 4k12
+		0x33316b34: 13, // 4k13
+		0x34316b34: 14, // 4k14
+	}
+
+	_4klangDelays []int = []int{ // these are the numerators, if denominator is 48, fraction of beat time
+		4,   // 0 = 4.0f * (1.0f/32.0f) * (2.0f/3.0f)
+		6,   // 1 = 4.0f * (1.0f/32.0f),
+		9,   // 2 = 4.0f * (1.0f/32.0f) * (3.0f/2.0f),
+		8,   // 3 = 4.0f * (1.0f/16.0f) * (2.0f/3.0f),
+		12,  // 4 = 4.0f * (1.0f/16.0f),
+		18,  // 5 = 4.0f * (1.0f/16.0f) * (3.0f/2.0f),
+		16,  // 6 = 4.0f * (1.0f/8.0f) * (2.0f/3.0f),
+		24,  // 7 = 4.0f * (1.0f/8.0f),
+		36,  // 8 = 4.0f * (1.0f/8.0f) * (3.0f/2.0f),
+		32,  // 9 = 4.0f * (1.0f/4.0f) * (2.0f/3.0f),
+		48,  // 10 = 4.0f * (1.0f/4.0f),
+		72,  // 11 = 4.0f * (1.0f/4.0f) * (3.0f/2.0f),
+		64,  // 12 = 4.0f * (1.0f/2.0f) * (2.0f/3.0f),
+		96,  // 13 = 4.0f * (1.0f/2.0f),
+		144, // 14 = 4.0f * (1.0f/2.0f) * (3.0f/2.0f),
+		128, // 15 = 4.0f * (1.0f) * (2.0f/3.0f),
+		192, // 16 = 4.0f * (1.0f),
+		288, // 17 = 4.0f * (1.0f) * (3.0f/2.0f),
+		256, // 18 = 4.0f * (2.0f) * (2.0f/3.0f),
+		384, // 19 = 4.0f * (2.0f),
+		576, // 20 = 4.0f * (2.0f) * (3.0f/2.0f),
+		72,  // 21 = 4.0f * (3.0f/8.0f),
+		120, // 22 = 4.0f * (5.0f/8.0f),
+		168, // 23 = 4.0f * (7.0f/8.0f),
+		216, // 24 = 4.0f * (9.0f/8.0f),
+		264, // 25 = 4.0f * (11.0f/8.0f),
+		312, // 26 = 4.0f * (13.0f/8.0f),
+		360, // 27 = 4.0f * (15.0f/8.0f),
+		144, // 28 = 4.0f * (3.0f/4.0f),
+		240, // 29 = 4.0f * (5.0f/4.0f),
+		336, // 30 = 4.0f * (7.0f/4.0f),
+		288, // 31 = 4.0f * (3.0f/2.0f),
+		288, // 32 = 4.0f * (3.0f/2.0f),
+	}
+
+	_4klangUnitPorts []_4klangPorts = []_4klangPorts{
+		{"", [8]string{"", "", "", "", "", "", "", ""}},
+		{"envelope", [8]string{"", "", "gain", "attack", "decay", "", "release", ""}},
+		{"oscillator", [8]string{"", "transpose", "detune", "", "phase", "color", "shape", "gain"}},
+		{"filter", [8]string{"", "", "", "", "frequency", "resonance", "", ""}},
+		{"envelope", [8]string{"", "", "drive", "frequency", "", "", "", ""}},
+		{"delay", [8]string{"pregain", "feedback", "dry", "damp", "", "", "", ""}},
+		{"", [8]string{"", "", "", "", "", "", "", ""}},
+		{"", [8]string{"", "", "", "", "", "", "", ""}},
+		{"pan", [8]string{"panning", "", "", "", "", "", "", ""}},
+		{"outaux", [8]string{"auxgain", "outgain", "", "", "", "", "", ""}},
+		{"", [8]string{"", "", "", "", "", "", "", ""}},
+		{"load", [8]string{"value", "", "", "", "", "", "", ""}},
+	}
+)
+
+func read4klangName(r io.Reader) (string, error) {
+	var name [_4KLANG_MAX_NAME_LEN]byte
+	if err := binary.Read(r, binary.LittleEndian, &name); err != nil {
+		return "", fmt.Errorf("binary.Read: %w", err)
+	}
+	n := bytes.IndexByte(name[:], 0)
+	if n == -1 {
+		n = _4KLANG_MAX_NAME_LEN
+	}
+	return string(name[:n]), nil
+}
+
+func read4klangUnits(r io.Reader, version, instrIndex int, m _4klangTargetMap, id *int) (units []Unit, err error) {
+	numUnits := _4KLANG_MAX_UNITS
+	if version <= 13 {
+		numUnits = 32
+	}
+	units = make([]Unit, 0, numUnits)
+	for unitIndex := 0; unitIndex < numUnits; unitIndex++ {
+		var u []Unit
+		if u, err = read4klangUnit(r, version); err != nil {
+			return nil, fmt.Errorf("read4klangUnit: %w", err)
+		}
+		if u == nil {
+			continue
+		}
+		m[_4klangStackUnit{instrIndex, unitIndex}] = *id
+		for i := range u {
+			u[i].ID = *id
+			*id++
+		}
+		units = append(units, u...)
+	}
+	return
+}
+
+func read4klangUnit(r io.Reader, version int) ([]Unit, error) {
+	var unitType byte
+	if err := binary.Read(r, binary.LittleEndian, &unitType); err != nil {
+		return nil, fmt.Errorf("binary.Read: %w", err)
+	}
+	var vals [15]byte
+	if err := binary.Read(r, binary.LittleEndian, &vals); err != nil {
+		return nil, fmt.Errorf("binary.Read: %w", err)
+	}
+	if version <= 13 {
+		// versions <= 13 had 16 unused slots for each unit
+		if written, err := io.CopyN(io.Discard, r, 16); err != nil || written < 16 {
+			return nil, fmt.Errorf("io.CopyN: %w", err)
+		}
+	}
+	switch unitType {
+	case 1:
+		return read4klangENV(vals, version), nil
+	case 2:
+		return read4klangVCO(vals, version), nil
+	case 3:
+		return read4klangVCF(vals, version), nil
+	case 4:
+		return read4klangDST(vals, version), nil
+	case 5:
+		return read4klangDLL(vals, version), nil
+	case 6:
+		return read4klangFOP(vals, version), nil
+	case 7:
+		return read4klangFST(vals, version), nil
+	case 8:
+		return read4klangPAN(vals, version), nil
+	case 9:
+		return read4klangOUT(vals, version), nil
+	case 10:
+		return read4klangACC(vals, version), nil
+	case 11:
+		return read4klangFLD(vals, version), nil
+	default:
+		return nil, nil
+	}
+}
+
+func read4klangENV(vals [15]byte, version int) []Unit {
+	return []Unit{{
+		Type: "envelope",
+		Parameters: map[string]int{
+			"stereo":  0,
+			"attack":  int(vals[0]),
+			"decay":   int(vals[1]),
+			"sustain": int(vals[2]),
+			"release": int(vals[3]),
+			"gain":    int(vals[4]),
+		},
+	}}
+}
+
+func read4klangVCO(vals [15]byte, version int) []Unit {
+	v := vals[:8]
+	var transpose, detune, phase, color, gate, shape, gain, flags, stereo, typ, lfo int
+	transpose, v = int(v[0]), v[1:]
+	detune, v = int(v[0]), v[1:]
+	phase, v = int(v[0]), v[1:]
+	if version <= 11 {
+		gate = 0x55
+	} else {
+		gate, v = int(v[0]), v[1:]
+	}
+	color, v = int(v[0]), v[1:]
+	shape, v = int(v[0]), v[1:]
+	gain, v = int(v[0]), v[1:]
+	flags, v = int(v[0]), v[1:]
+	if flags&0x10 == 0x10 {
+		lfo = 1
+	}
+	if flags&0x40 == 0x40 {
+		stereo = 1
+	}
+	switch {
+	case flags&0x01 == 0x01: // Sine
+		typ = Sine
+		if version <= 13 {
+			color = 128
+		}
+	case flags&0x02 == 0x02: // Trisaw
+		typ = Trisaw
+	case flags&0x04 == 0x04: // Pulse
+		typ = Pulse
+	case flags&0x08 == 0x08: // Noise is handled differently in sointu
+		return []Unit{{
+			Type: "noise",
+			Parameters: map[string]int{
+				"stereo": stereo,
+				"shape":  shape,
+				"gain":   gain,
+			},
+		}}
+	case flags&0x20 == 0x20: // Gate
+		color = gate
+	}
+	return []Unit{{
+		Type: "oscillator",
+		Parameters: map[string]int{
+			"stereo":    stereo,
+			"transpose": transpose,
+			"detune":    detune,
+			"phase":     phase,
+			"color":     color,
+			"shape":     shape,
+			"gain":      gain,
+			"type":      typ,
+			"lfo":       lfo,
+		},
+	}}
+}
+
+func read4klangVCF(vals [15]byte, version int) []Unit {
+	flags := vals[2]
+	var stereo, lowpass, bandpass, highpass, neghighpass int
+	if flags&0x01 == 0x01 {
+		lowpass = 1
+	}
+	if flags&0x02 == 0x02 {
+		highpass = 1
+	}
+	if flags&0x04 == 0x04 {
+		bandpass = 1
+	}
+	if flags&0x08 == 0x08 {
+		lowpass = 1
+		neghighpass = 1
+	}
+	if flags&0x10 == 0x10 {
+		stereo = 1
+	}
+	return []Unit{{
+		Type: "filter",
+		Parameters: map[string]int{
+			"stereo":      stereo,
+			"frequency":   int(vals[0]),
+			"resonance":   int(vals[1]),
+			"lowpass":     lowpass,
+			"bandpass":    bandpass,
+			"highpass":    highpass,
+			"negbandpass": 0,
+			"neghighpass": neghighpass,
+		}},
+	}
+}
+
+func read4klangDST(vals [15]byte, version int) []Unit {
+	return []Unit{
+		{Type: "distort", Parameters: map[string]int{"drive": int(vals[0]), "stereo": int(vals[2])}},
+		{Type: "hold", Parameters: map[string]int{"holdfreq": int(vals[1]), "stereo": int(vals[2])}},
+	}
+}
+
+func read4klangDLL(vals [15]byte, version int) []Unit {
+	var delaytimes []int
+	var notetracking int
+	if vals[11] > 0 {
+		if vals[10] > 0 { // left reverb
+			delaytimes = []int{1116, 1188, 1276, 1356, 1422, 1492, 1556, 1618}
+		} else { // right reverb
+			delaytimes = []int{1140, 1212, 1300, 1380, 1446, 1516, 1580, 1642}
+		}
+	} else {
+		synctype := vals[9]
+		switch synctype {
+		case 0:
+			delaytimes = []int{int(vals[8]) * 16}
+		case 1: // relative to BPM
+			notetracking = 2
+			index := vals[8] >> 2
+			delaytime := 48
+			if int(index) < len(_4klangDelays) {
+				delaytime = _4klangDelays[index]
+			}
+			delaytimes = []int{delaytime}
+		case 2: // notetracking
+			notetracking = 1
+			delaytimes = []int{10787}
+		}
+	}
+	return []Unit{{
+		Type: "delay",
+		Parameters: map[string]int{
+			"stereo":       0,
+			"pregain":      int(vals[0]),
+			"dry":          int(vals[1]),
+			"feedback":     int(vals[2]),
+			"damp":         int(vals[3]),
+			"notetracking": notetracking,
+		},
+		VarArgs: delaytimes,
+	}}
+}
+
+func read4klangFOP(vals [15]byte, version int) []Unit {
+	var t string
+	var stereo int
+	switch vals[0] {
+	case 1:
+		t, stereo = "pop", 0
+	case 2:
+		t, stereo = "addp", 0
+	case 3:
+		t, stereo = "mulp", 0
+	case 4:
+		t, stereo = "push", 0
+	case 5:
+		t, stereo = "xch", 0
+	case 6:
+		t, stereo = "add", 0
+	case 7:
+		t, stereo = "mul", 0
+	case 8:
+		t, stereo = "addp", 1
+	case 9:
+		return []Unit{{Type: "loadnote", Parameters: map[string]int{"stereo": stereo}}, // 4klang loadnote gives 0..1, sointu gives -1..1
+			{Type: "loadval", Parameters: map[string]int{"value": 128, "stereo": stereo}},
+			{Type: "addp", Parameters: map[string]int{"stereo": stereo}},
+			{Type: "gain", Parameters: map[string]int{"stereo": stereo, "gain": 64}}}
+	default:
+		t, stereo = "mulp", 1
+	}
+	return []Unit{{
+		Type:       t,
+		Parameters: map[string]int{"stereo": stereo},
+	}}
+}
+
+func read4klangFST(vals [15]byte, version int) []Unit {
+	sendpop := 0
+	if vals[1]&0x40 == 0x40 {
+		sendpop = 1
+	}
+	return []Unit{{
+		Type: "send",
+		Parameters: map[string]int{
+			"amount":     int(vals[0]),
+			"sendpop":    sendpop,
+			"dest_stack": int(vals[2]),
+			"dest_unit":  int(vals[3]),
+			"dest_slot":  int(vals[4]),
+			"dest_id":    int(vals[5]),
+		}}}
+}
+
+func fix4klangTargets(instrIndex int, instr Instrument, m _4klangTargetMap) {
+	for _, u := range instr.Units {
+		if u.Type == "send" {
+			destStack := u.Parameters["dest_stack"]
+			if destStack == 255 {
+				destStack = instrIndex
+			}
+			fourKlangTarget := _4klangStackUnit{
+				destStack,
+				u.Parameters["dest_unit"]}
+			u.Parameters["target"] = m[fourKlangTarget]
+			if u.Parameters["dest_id"] < len(_4klangUnitPorts) && u.Parameters["dest_slot"] < 8 {
+				if u.Parameters["dest_id"] == 4 && u.Parameters["dest_slot"] == 3 { // distortion is split into 2 units
+					u.Parameters["target"]++
+					u.Parameters["port"] = 0
+				} else {
+					modTarget := _4klangUnitPorts[u.Parameters["dest_id"]]
+					for i, s := range Ports[modTarget.UnitType] {
+						if s == modTarget.PortName[u.Parameters["dest_slot"]] {
+							u.Parameters["port"] = i
+							break
+						}
+					}
+				}
+			}
+			delete(u.Parameters, "dest_stack")
+			delete(u.Parameters, "dest_unit")
+			delete(u.Parameters, "dest_slot")
+			delete(u.Parameters, "dest_id")
+		}
+	}
+}
+
+func read4klangPAN(vals [15]byte, version int) []Unit {
+	return []Unit{{
+		Type: "pan",
+		Parameters: map[string]int{
+			"stereo":  0,
+			"panning": int(vals[0]),
+		}}}
+}
+
+func read4klangOUT(vals [15]byte, version int) []Unit {
+	return []Unit{{
+		Type: "outaux",
+		Parameters: map[string]int{
+			"stereo":  1,
+			"outgain": int(vals[0]),
+			"auxgain": int(vals[1])},
+	}}
+}
+
+func read4klangACC(vals [15]byte, version int) []Unit {
+	c := 0
+	if vals[0] != 0 {
+		c = 2
+	}
+	return []Unit{{
+		Type:       "in",
+		Parameters: map[string]int{"stereo": 1, "channel": c},
+	}}
+}
+
+func read4klangFLD(vals [15]byte, version int) []Unit {
+	return []Unit{{
+		Type:       "loadval",
+		Parameters: map[string]int{"stereo": 0, "value": int(vals[0])},
+	}}
+}

patch.go

@@ -192,6 +192,18 @@ func (p Patch) ParamHintString(instrIndex, unitIndex int, param string) string {
 			}
 			return fmt.Sprintf(portList[value])
 		}
+	case "delay":
+		switch param {
+		case "notetracking":
+			switch value {
+			case 0:
+				return "fixed"
+			case 1:
+				return "tracks pitch"
+			case 2:
+				return "tracks BPM"
+			}
+		}
 	}
 	return ""
 }

synth.go

@@ -22,7 +22,7 @@ type Synth interface {
 	// delaylines should keep their content. Every change in the Patch triggers
 	// an Update and if the Patch would be started fresh every time, it would
 	// lead to very choppy audio.
-	Update(patch Patch) error
+	Update(patch Patch, bpm int) error
 
 	// Trigger triggers a note for a given voice. Called between synth.Renders.
 	Trigger(voice int, note byte)
@@ -35,7 +35,7 @@ type Synth interface {
 // SynthService compiles a given Patch into a Synth, throwing errors if the
 // Patch is malformed.
 type SynthService interface {
-	Compile(patch Patch) (Synth, error)
+	Compile(patch Patch, bpm int) (Synth, error)
 }
 
 // Render fills an stereo audio buffer using a Synth, disregarding all syncs and
@@ -62,7 +62,7 @@ func Play(synthService SynthService, song Song, release bool) ([]float32, error)
 	if err != nil {
 		return nil, err
 	}
-	synth, err := synthService.Compile(song.Patch)
+	synth, err := synthService.Compile(song.Patch, song.BPM)
 	if err != nil {
 		return nil, fmt.Errorf("sointu.Play failed: %v", err)
 	}

tracker/gioui/filedialog.go

@@ -106,9 +106,9 @@ func (f *FileDialogStyle) Layout(gtx C) D {
 				n = n[0 : len(n)-len(extension)]
 				switch f.dialog.UseAltExt.Value {
 				case true:
-					n += ".json"
+					n += f.ExtAlt
 				default:
-					n += ".yml"
+					n += f.ExtMain
 				}
 				f.dialog.FileName.SetText(n)
 			}

tracker/gioui/files.go

@@ -4,6 +4,7 @@
 package gioui
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
@@ -66,15 +67,23 @@ func (t *Tracker) SaveInstrument() {
 }
 
 func (t *Tracker) loadSong(filename string) {
-	bytes, err := ioutil.ReadFile(filename)
+	b, err := ioutil.ReadFile(filename)
 	if err != nil {
 		return
 	}
 	var song sointu.Song
-	if errJSON := json.Unmarshal(bytes, &song); errJSON != nil {
-		if errYaml := yaml.Unmarshal(bytes, &song); errYaml != nil {
-			t.Alert.Update(fmt.Sprintf("Error unmarshaling a song file: %v / %v", errYaml, errJSON), Error, time.Second*3)
-			return
+	if errJSON := json.Unmarshal(b, &song); errJSON != nil {
+		if errYaml := yaml.Unmarshal(b, &song); errYaml != nil {
+			var err4kp error
+			var patch sointu.Patch
+			if patch, err4kp = sointu.Read4klangPatch(bytes.NewReader(b)); err4kp != nil {
+				t.Alert.Update(fmt.Sprintf("Error unmarshaling a song file: %v / %v / %v", errYaml, errJSON, err4kp), Error, time.Second*3)
+				return
+			} else {
+				song = t.Song()
+				song.Score = t.Song().Score.Copy()
+				song.Patch = patch
+			}
 		}
 	}
 	if song.Score.Length <= 0 || len(song.Score.Tracks) == 0 || len(song.Patch) == 0 {
@@ -148,17 +157,22 @@ func (t *Tracker) saveInstrument(filename string) bool {
 }
 
 func (t *Tracker) loadInstrument(filename string) bool {
-	bytes, err := ioutil.ReadFile(filename)
+	b, err := ioutil.ReadFile(filename)
 	if err != nil {
 		return false
 	}
 	var instrument sointu.Instrument
-	if errJSON := json.Unmarshal(bytes, &instrument); errJSON != nil {
-		if errYaml := yaml.Unmarshal(bytes, &instrument); errYaml != nil {
-			t.Alert.Update(fmt.Sprintf("Error unmarshaling an instrument file: %v / %v", errYaml, errJSON), Error, time.Second*3)
-			return false
+	if errJSON := json.Unmarshal(b, &instrument); errJSON != nil {
+		if errYaml := yaml.Unmarshal(b, &instrument); errYaml != nil {
+			var err4ki error
+			if instrument, err4ki = sointu.Read4klangInstrument(bytes.NewReader(b)); err4ki != nil {
+				t.Alert.Update(fmt.Sprintf("Error unmarshaling an instrument file: %v / %v / %v", errYaml, errJSON, err4ki), Error, time.Second*3)
+				return false
+			}
 		}
 	}
+	// the 4klang instrument names are junk, replace them with the filename without extension
+	instrument.Name = filepath.Base(filename[:len(filename)-len(filepath.Ext(filename))])
 	if len(instrument.Units) == 0 {
 		t.Alert.Update("The instrument file is malformed", Error, time.Second*3)
 		return false

tracker/gioui/layout.go

@@ -58,6 +58,7 @@ func (t *Tracker) Layout(gtx layout.Context) {
 	}
 	fstyle := OpenFileDialog(t.Theme, t.OpenSongDialog)
 	fstyle.Title = "Open Song File"
+	fstyle.ExtAlt = ".4kp"
 	fstyle.Layout(gtx)
 	for ok, file := t.OpenSongDialog.FileSelected(); ok; ok, file = t.OpenSongDialog.FileSelected() {
 		t.loadSong(file)
@@ -89,6 +90,7 @@ func (t *Tracker) Layout(gtx layout.Context) {
 	fstyle.Layout(gtx)
 	fstyle = OpenFileDialog(t.Theme, t.OpenInstrumentDialog)
 	fstyle.Title = "Open Instrument File"
+	fstyle.ExtAlt = ".4ki"
 	for ok, file := t.OpenInstrumentDialog.FileSelected(); ok; ok, file = t.OpenInstrumentDialog.FileSelected() {
 		t.loadInstrument(file)
 	}

tracker/model.go

@@ -66,7 +66,7 @@ type (
 	}
 
 	ModelSamplesPerRowChangedMessage struct {
-		int
+		BPM, RowsPerBeat int
 	}
 
 	ModelPanicMessage struct {
@@ -1088,14 +1088,43 @@ func (m *Model) Param(index int) (Parameter, error) {
 		if index < len(unit.VarArgs) {
 			val := unit.VarArgs[index]
 			var text string
-			if unit.Parameters["notetracking"] == 1 {
+			switch unit.Parameters["notetracking"] {
+			default:
+			case 0:
+				text = fmt.Sprintf("%v / %.3f rows", val, float32(val)/float32(m.song.SamplesPerRow()))
+				return Parameter{Type: IntegerParameter, Min: 1, Max: 65535, Name: "delaytime", Hint: text, Value: val, LargeStep: 256}, nil
+			case 1:
 				relPitch := float64(val) / 10787
 				semitones := -math.Log2(relPitch) * 12
 				text = fmt.Sprintf("%v / %.3f st", val, semitones)
-			} else {
-				text = fmt.Sprintf("%v / %.3f rows", val, float32(val)/float32(m.song.SamplesPerRow()))
+				return Parameter{Type: IntegerParameter, Min: 1, Max: 65535, Name: "delaytime", Hint: text, Value: val, LargeStep: 256}, nil
+			case 2:
+				k := 0
+				v := val
+				for v&1 == 0 { // divide val by 2 until it is odd
+					v >>= 1
+					k++
+				}
+				text := ""
+				switch v {
+				case 1:
+					if k <= 7 {
+						text = fmt.Sprintf(" (1/%d triplet)", 1<<(7-k))
+					}
+				case 3:
+					if k <= 6 {
+						text = fmt.Sprintf(" (1/%d)", 1<<(6-k))
+					}
+					break
+				case 9:
+					if k <= 5 {
+						text = fmt.Sprintf(" (1/%d dotted)", 1<<(5-k))
+					}
+				}
+				text = fmt.Sprintf("%v / %.3f beats%s", val, float32(val)/48.0, text)
+				return Parameter{Type: IntegerParameter, Min: 1, Max: 576, Name: "delaytime", Hint: text, Value: val, LargeStep: 16}, nil
 			}
-			return Parameter{Type: IntegerParameter, Min: 1, Max: 65535, Name: "delaytime", Hint: text, Value: val, LargeStep: 256}, nil
+
 		}
 	}
 	return Parameter{}, errors.New("invalid parameter")
@@ -1240,7 +1269,7 @@ func (m *Model) notifyScoreChange() {
 
 func (m *Model) notifySamplesPerRowChange() {
 	select {
-	case m.modelMessages <- ModelSamplesPerRowChangedMessage{m.song.SamplesPerRow()}:
+	case m.modelMessages <- ModelSamplesPerRowChangedMessage{m.song.BPM, m.song.RowsPerBeat}:
 	default:
 	}
 }

tracker/player.go

@@ -20,6 +20,7 @@ type (
 		position          SongRow
 		samplesSinceEvent []int
 		samplesPerRow     int
+		bpm               int
 		volume            Volume
 		voiceStates       [vm.MAX_VOICES]float32
 
@@ -242,7 +243,9 @@ loop:
 					}
 				}
 			case ModelSamplesPerRowChangedMessage:
-				p.samplesPerRow = m.int
+				p.samplesPerRow = 44100 * 60 / (m.BPM * m.RowsPerBeat)
+				p.bpm = m.BPM
+				p.compileOrUpdateSynth()
 			case ModelPlayFromPositionMessage:
 				p.playing = true
 				p.position = m.SongRow
@@ -297,7 +300,7 @@ loop:
 
 func (p *Player) compileOrUpdateSynth() {
 	if p.synth != nil {
-		err := p.synth.Update(p.patch)
+		err := p.synth.Update(p.patch, p.bpm)
 		if err != nil {
 			p.synth = nil
 			p.trySend(PlayerCrashMessage{fmt.Errorf("synth.Update: %w", err)})
@@ -305,7 +308,7 @@ func (p *Player) compileOrUpdateSynth() {
 		}
 	} else {
 		var err error
-		p.synth, err = p.synthService.Compile(p.patch)
+		p.synth, err = p.synthService.Compile(p.patch, p.bpm)
 		if err != nil {
 			p.synth = nil
 			p.trySend(PlayerCrashMessage{fmt.Errorf("synthService.Compile: %w", err)})

unittype.go

@@ -58,7 +58,7 @@ var UnitTypes = map[string]([]UnitParameter){
 		{Name: "dry", MinValue: 0, MaxValue: 128, CanSet: true, CanModulate: true},
 		{Name: "feedback", MinValue: 0, MaxValue: 128, CanSet: true, CanModulate: true},
 		{Name: "damp", MinValue: 0, MaxValue: 128, CanSet: true, CanModulate: true},
-		{Name: "notetracking", MinValue: 0, MaxValue: 1, CanSet: true, CanModulate: false},
+		{Name: "notetracking", MinValue: 0, MaxValue: 2, CanSet: true, CanModulate: false},
 		{Name: "delaytime", MinValue: 0, MaxValue: -1, CanSet: false, CanModulate: true}},
 	"compressor": []UnitParameter{
 		{Name: "stereo", MinValue: 0, MaxValue: 1, CanSet: true, CanModulate: false},

vm/bytepatch.go

@@ -33,7 +33,7 @@ type SampleOffset struct {
 	LoopLength uint16
 }
 
-func Encode(patch sointu.Patch, featureSet FeatureSet) (*BytePatch, error) {
+func Encode(patch sointu.Patch, featureSet FeatureSet, bpm int) (*BytePatch, error) {
 	c := BytePatch{PolyphonyBitmask: polyphonyBitmask(patch), NumVoices: uint32(patch.NumVoices())}
 	if c.NumVoices > 32 {
 		return nil, fmt.Errorf("Sointu does not support more than 32 concurrent voices; patch uses %v", c.NumVoices)
@@ -42,7 +42,7 @@ func Encode(patch sointu.Patch, featureSet FeatureSet) (*BytePatch, error) {
 	globalAddrs := map[int]uint16{}
 	globalFixups := map[int]([]int){}
 	voiceNo := 0
-	delayTable, delayIndices := constructDelayTimeTable(patch)
+	delayTable, delayIndices := constructDelayTimeTable(patch, bpm)
 	c.DelayTimes = make([]uint16, len(delayTable))
 	for i := range delayTable {
 		c.DelayTimes[i] = uint16(delayTable[i])
@@ -171,7 +171,7 @@ func Encode(patch sointu.Patch, featureSet FeatureSet) (*BytePatch, error) {
 				if count == 0 {
 					continue // skip encoding delays without any delay lines
 				}
-				countTrack := count*2 - 1 + unit.Parameters["notetracking"] // 1 means no note tracking and 1 delay, 2 means notetracking with 1 delay, 3 means no note tracking and 2 delays etc.
+				countTrack := count*2 - 1 + (unit.Parameters["notetracking"] & 1) // 1 means no note tracking and 1 delay, 2 means notetracking with 1 delay, 3 means no note tracking and 2 delays etc.
 				values = append(values, byte(delayIndices[instrIndex][unitIndex]), byte(countTrack))
 			}
 			c.Commands = append(c.Commands, byte(opcode+unit.Parameters["stereo"]))

vm/compiler/bridge/bridge.go

@@ -16,17 +16,17 @@ import (
 type BridgeService struct {
 }
 
-func (s BridgeService) Compile(patch sointu.Patch) (sointu.Synth, error) {
-	synth, err := Synth(patch)
+func (s BridgeService) Compile(patch sointu.Patch, bpm int) (sointu.Synth, error) {
+	synth, err := Synth(patch, bpm)
 	return synth, err
 }
 
-func Synth(patch sointu.Patch) (*C.Synth, error) {
+func Synth(patch sointu.Patch, bpm int) (*C.Synth, error) {
 	s := new(C.Synth)
 	if n := patch.NumDelayLines(); n > 64 {
 		return nil, fmt.Errorf("native bridge has currently a hard limit of 64 delaylines; patch uses %v", n)
 	}
-	comPatch, err := vm.Encode(patch, vm.AllFeatures{})
+	comPatch, err := vm.Encode(patch, vm.AllFeatures{}, bpm)
 	if err != nil {
 		return nil, fmt.Errorf("error compiling patch: %v", err)
 	}
@@ -109,11 +109,11 @@ func (s *C.Synth) Release(voice int) {
 }
 
 // Update
-func (s *C.Synth) Update(patch sointu.Patch) error {
+func (s *C.Synth) Update(patch sointu.Patch, bpm int) error {
 	if n := patch.NumDelayLines(); n > 64 {
 		return fmt.Errorf("native bridge has currently a hard limit of 64 delaylines; patch uses %v", n)
 	}
-	comPatch, err := vm.Encode(patch, vm.AllFeatures{})
+	comPatch, err := vm.Encode(patch, vm.AllFeatures{}, bpm)
 	if err != nil {
 		return fmt.Errorf("error compiling patch: %v", err)
 	}

vm/compiler/bridge/bridge_test.go

@@ -54,7 +54,7 @@ func TestRenderSamples(t *testing.T) {
 		sointu.Unit{Type: "out", Parameters: map[string]int{"stereo": 1, "gain": 128}},
 	}}}
 
-	synth, err := bridge.Synth(patch)
+	synth, err := bridge.Synth(patch, 120)
 	if err != nil {
 		t.Fatalf("bridge compile error: %v", err)
 	}
@@ -130,7 +130,7 @@ func TestStackUnderflow(t *testing.T) {
 	patch := sointu.Patch{sointu.Instrument{NumVoices: 1, Units: []sointu.Unit{
 		sointu.Unit{Type: "pop", Parameters: map[string]int{}},
 	}}}
-	synth, err := bridge.Synth(patch)
+	synth, err := bridge.Synth(patch, 120)
 	if err != nil {
 		t.Fatalf("bridge compile error: %v", err)
 	}
@@ -146,7 +146,7 @@ func TestStackBalancing(t *testing.T) {
 		sointu.Instrument{NumVoices: 1, Units: []sointu.Unit{
 			sointu.Unit{Type: "push", Parameters: map[string]int{}},
 		}}}
-	synth, err := bridge.Synth(patch)
+	synth, err := bridge.Synth(patch, 120)
 	if err != nil {
 		t.Fatalf("bridge compile error: %v", err)
 	}
@@ -179,7 +179,7 @@ func TestStackOverflow(t *testing.T) {
 			sointu.Unit{Type: "pop", Parameters: map[string]int{}},
 			sointu.Unit{Type: "pop", Parameters: map[string]int{}},
 		}}}
-	synth, err := bridge.Synth(patch)
+	synth, err := bridge.Synth(patch, 120)
 	if err != nil {
 		t.Fatalf("bridge compile error: %v", err)
 	}
@@ -196,7 +196,7 @@ func TestDivideByZero(t *testing.T) {
 		sointu.Unit{Type: "invgain", Parameters: map[string]int{"invgain": 0}},
 		sointu.Unit{Type: "pop", Parameters: map[string]int{}},
 	}}}
-	synth, err := bridge.Synth(patch)
+	synth, err := bridge.Synth(patch, 120)
 	if err != nil {
 		t.Fatalf("bridge compile error: %v", err)
 	}

vm/compiler/compiler.go

@@ -84,7 +84,7 @@ func (com *Compiler) Song(song *sointu.Song) (map[string]string, error) {
 	}
 	features := vm.NecessaryFeaturesFor(song.Patch)
 	retmap := map[string]string{}
-	encodedPatch, err := vm.Encode(song.Patch, features)
+	encodedPatch, err := vm.Encode(song.Patch, features, song.BPM)
 	if err != nil {
 		return nil, fmt.Errorf(`could not encode patch: %v`, err)
 	}

vm/delaytable.go

@@ -107,7 +107,7 @@ func findSuperIntArray(arrays [][]int) ([]int, []int) {
 // Returns the delay time table and two dimensional array of integers where
 // element [i][u] is the index for instrument i / unit u in the delay table if
 // the unit was a delay unit. For non-delay untis, the element is just 0.
-func constructDelayTimeTable(patch sointu.Patch) ([]int, [][]int) {
+func constructDelayTimeTable(patch sointu.Patch, bpm int) ([]int, [][]int) {
 	ind := make([][]int, len(patch))
 	var subarrays [][]int
 	// flatten the delay times into one array of arrays
@@ -119,11 +119,18 @@ func constructDelayTimeTable(patch sointu.Patch) ([]int, [][]int) {
 			// should use delay times
 			if unit.Type == "delay" {
 				ind[i][j] = len(subarrays)
-				end := unit.Parameters["count"]
-				if unit.Parameters["stereo"] > 0 {
-					end *= 2
+				converted := make([]int, len(unit.VarArgs))
+				copy(converted, unit.VarArgs)
+				if unit.Parameters["notetracking"] == 2 {
+					for i, t := range converted {
+						delay := 44100 * 60 * t / 48 / bpm
+						if delay > 65535 {
+							delay = 65535
+						}
+						converted[i] = delay
+					}
 				}
-				subarrays = append(subarrays, unit.VarArgs)
+				subarrays = append(subarrays, converted)
 			}
 		}
 	}

vm/interpreter.go

@@ -63,8 +63,8 @@ const (
 	envStateRelease
 )
 
-func Synth(patch sointu.Patch) (sointu.Synth, error) {
-	bytePatch, err := Encode(patch, AllFeatures{})
+func Synth(patch sointu.Patch, bpm int) (sointu.Synth, error) {
+	bytePatch, err := Encode(patch, AllFeatures{}, bpm)
 	if err != nil {
 		return nil, fmt.Errorf("error compiling %v", err)
 	}
@@ -73,8 +73,8 @@ func Synth(patch sointu.Patch) (sointu.Synth, error) {
 	return ret, nil
 }
 
-func (s SynthService) Compile(patch sointu.Patch) (sointu.Synth, error) {
-	synth, err := Synth(patch)
+func (s SynthService) Compile(patch sointu.Patch, bpm int) (sointu.Synth, error) {
+	synth, err := Synth(patch, bpm)
 	return synth, err
 }
 
@@ -87,8 +87,8 @@ func (s *Interpreter) Release(voiceIndex int) {
 	s.synth.voices[voiceIndex].release = true
 }
 
-func (s *Interpreter) Update(patch sointu.Patch) error {
-	bytePatch, err := Encode(patch, AllFeatures{})
+func (s *Interpreter) Update(patch sointu.Patch, bpm int) error {
+	bytePatch, err := Encode(patch, AllFeatures{}, bpm)
 	if err != nil {
 		return fmt.Errorf("error compiling %v", err)
 	}
@@ -140,9 +140,11 @@ func (s *Interpreter) Render(buffer []float32, maxtime int) (samples int, time i
 			stereo := channels == 2
 			opNoStereo := (op & 0xFE) >> 1
 			if opNoStereo == 0 {
-				voices = voices[1:]
-				units = voices[0].units[:]
 				voicesRemaining--
+				if voicesRemaining > 0 {
+					voices = voices[1:]
+					units = voices[0].units[:]
+				}
 				if mask := uint32(1) << uint32(voicesRemaining); s.bytePatch.PolyphonyBitmask&mask == mask {
 					commands, values = commandInstr, valuesInstr
 				} else {

vm/interpreter_test.go

@@ -76,7 +76,7 @@ func TestStackUnderflow(t *testing.T) {
 	patch := sointu.Patch{sointu.Instrument{NumVoices: 1, Units: []sointu.Unit{
 		sointu.Unit{Type: "pop", Parameters: map[string]int{}},
 	}}}
-	synth, err := vm.Synth(patch)
+	synth, err := vm.Synth(patch, 120)
 	if err != nil {
 		t.Fatalf("bridge compile error: %v", err)
 	}
@@ -92,7 +92,7 @@ func TestStackBalancing(t *testing.T) {
 		sointu.Instrument{NumVoices: 1, Units: []sointu.Unit{
 			sointu.Unit{Type: "push", Parameters: map[string]int{}},
 		}}}
-	synth, err := vm.Synth(patch)
+	synth, err := vm.Synth(patch, 120)
 	if err != nil {
 		t.Fatalf("bridge compile error: %v", err)
 	}