feat(tracker): add reverb presets for delay unit

The options are stereo, left and right. Similar to oscillator sample settings, if you tamper with these, it starts to show "custom". Used some of the generic features of go1.18, so had to update go.mod to require go1.18.

CHANGELOG.md

@@ -11,6 +11,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Instrument presets. The presets are embedded in the executable and
   there's a button to open a menu to load one of the presets.
 - Frequency modulation target for oscillator, as it was in 4klang
+- Reverb preset settings for a delay unit, with stereo, left and right
+  options
 
 ### Fixed
 - The sointu-vsti-native plugin has different plugin ID and plugin name

go.mod

@@ -1,6 +1,6 @@
 module github.com/vsariola/sointu
 
-go 1.17
+go 1.18
 
 require (
 	gioui.org v0.3.0

tracker/defaultsong.go

@@ -78,6 +78,20 @@ var defaultSong = sointu.Song{
 		}}},
 }
 
+type delayPreset struct {
+	name    string
+	stereo  int
+	varArgs []int
+}
+
+var reverbs = []delayPreset{
+	{"stereo", 1, []int{1116, 1188, 1276, 1356, 1422, 1492, 1556, 1618,
+		1140, 1212, 1300, 1380, 1446, 1516, 1580, 1642,
+	}},
+	{"left", 0, []int{1116, 1188, 1276, 1356, 1422, 1492, 1556, 1618}},
+	{"right", 0, []int{1140, 1212, 1300, 1380, 1446, 1516, 1580, 1642}},
+}
+
 func init() {
 	UnitTypeNames = make([]string, 0, len(sointu.UnitTypes))
 	for k := range sointu.UnitTypes {

tracker/model.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/vsariola/sointu"
 	"github.com/vsariola/sointu/vm"
+	"golang.org/x/exp/slices"
 	"gopkg.in/yaml.v2"
 )
 
@@ -863,6 +864,23 @@ func (m *Model) setGmDlsEntry(index int) {
 	m.notifyPatchChange()
 }
 
+func (m *Model) setReverb(index int) {
+	if index < 0 || index >= len(reverbs) {
+		return
+	}
+	entry := reverbs[index]
+	unit := &m.d.Song.Patch[m.d.InstrIndex].Units[m.d.UnitIndex]
+	if unit.Type != "delay" {
+		return
+	}
+	m.saveUndo("setReverb", 20)
+	unit.Parameters["stereo"] = entry.stereo
+	unit.Parameters["notetracking"] = 0
+	unit.VarArgs = make([]int, len(entry.varArgs))
+	copy(unit.VarArgs, entry.varArgs)
+	m.notifyPatchChange()
+}
+
 func (m *Model) SwapUnits(i, j int) {
 	units := m.Instrument().Units
 	if i < 0 || j < 0 || i >= len(units) || j >= len(units) || i == j {
@@ -1121,7 +1139,7 @@ func (m *Model) NumParams() int {
 		numSettableParams = 1
 	}
 	if unit.Type == "delay" {
-		numSettableParams += 1 + len(unit.VarArgs)
+		numSettableParams += 2 + len(unit.VarArgs)
 		if len(unit.VarArgs)%2 == 1 && unit.Parameters["stereo"] == 1 {
 			numSettableParams++
 		}
@@ -1181,13 +1199,23 @@ func (m *Model) Param(index int) (Parameter, error) {
 	}
 	if unit.Type == "delay" {
 		if index == 0 {
+			i := slices.IndexFunc(reverbs, func(p delayPreset) bool {
+				return p.stereo == unit.Parameters["stereo"] && unit.Parameters["notetracking"] == 0 && slices.Equal(p.varArgs, unit.VarArgs)
+			})
+			hint := "0 / custom"
+			if i >= 0 {
+				hint = fmt.Sprintf("%v / %v", i+1, reverbs[i].name)
+			}
+			return Parameter{Type: IntegerParameter, Min: 0, Max: len(reverbs), Name: "reverb", Hint: hint, Value: i + 1}, nil
+		}
+		if index == 1 {
 			l := len(unit.VarArgs)
 			if unit.Parameters["stereo"] == 1 {
 				l = (l + 1) / 2
 			}
 			return Parameter{Type: IntegerParameter, Min: 1, Max: 32, Name: "delaylines", Hint: strconv.Itoa(l), Value: l}, nil
 		}
-		index--
+		index -= 2
 		if index < len(unit.VarArgs) {
 			val := unit.VarArgs[index]
 			var text string
@@ -1305,6 +1333,10 @@ func (m *Model) SetParam(value int) {
 		m.setGmDlsEntry(value - 1)
 		return
 	}
+	if p.Name == "reverb" {
+		m.setReverb(value - 1)
+		return
+	}
 	unit := m.Unit()
 	if p.Name == "delaylines" {
 		m.saveUndo("SetParam", 20)
@@ -1318,7 +1350,7 @@ func (m *Model) SetParam(value int) {
 		m.Instrument().Units[m.d.UnitIndex].VarArgs = m.Instrument().Units[m.d.UnitIndex].VarArgs[:targetLines]
 	} else if p.Name == "delaytime" {
 		m.saveUndo("SetParam", 20)
-		index := m.d.ParamIndex - 7
+		index := m.d.ParamIndex - 8
 		for len(m.Instrument().Units[m.d.UnitIndex].VarArgs) <= index {
 			m.Instrument().Units[m.d.UnitIndex].VarArgs = append(m.Instrument().Units[m.d.UnitIndex].VarArgs, 1)
 		}