feat(sointu): add SynthService for recompiling the synth when needed

bridge/bridge.go

@@ -13,6 +13,14 @@ import (
 	"github.com/vsariola/sointu/compiler"
 )
 
+type BridgeService struct {
+}
+
+func (s BridgeService) Compile(patch sointu.Patch) (sointu.Synth, error) {
+	synth, err := Synth(patch)
+	return synth, err
+}
+
 func Synth(patch sointu.Patch) (*C.Synth, error) {
 	s := new(C.Synth)
 	comPatch, err := compiler.Encode(&patch, compiler.AllFeatures{})

cmd/sointu-track/main.go

@@ -6,6 +6,7 @@ import (
 
 	"gioui.org/app"
 	"gioui.org/unit"
+	"github.com/vsariola/sointu/bridge"
 	"github.com/vsariola/sointu/oto"
 	"github.com/vsariola/sointu/tracker"
 )
@@ -17,12 +18,13 @@ func main() {
 		os.Exit(1)
 	}
 	defer audioContext.Close()
+	synthService := bridge.BridgeService{}
 	go func() {
 		w := app.NewWindow(
 			app.Size(unit.Dp(800), unit.Dp(600)),
 			app.Title("Sointu Tracker"),
 		)
-		t := tracker.New(audioContext)
+		t := tracker.New(audioContext, synthService)
 		defer t.Close()
 		if err := t.Run(w); err != nil {
 			fmt.Println(err)

sointu.go

@@ -120,6 +120,10 @@ func Render(synth Synth, buffer []float32) error {
 	return nil
 }
 
+type SynthService interface {
+	Compile(patch Patch) (Synth, error)
+}
+
 type AudioSink interface {
 	WriteAudio(buffer []float32) (err error)
 	Close() error

tracker/sequencer.go

@@ -1,7 +1,6 @@
 package tracker
 
 import (
-	"errors"
 	"fmt"
 	"math"
 	"sync"
@@ -24,6 +23,7 @@ type Sequencer struct {
 	// that the synth is not changed when audio is being read
 	mutex   sync.Mutex
 	synth   sointu.Synth
+	service sointu.SynthService
 	// this iterator is a bit unconventional in the sense that it might return
 	// hasNext false, but might still return hasNext true in future attempts if
 	// new rows become available.
@@ -37,11 +37,11 @@ type Note struct {
 	Note  byte
 }
 
-func NewSequencer(synth sointu.Synth, rowLength int, iterator func() ([]Note, bool)) *Sequencer {
+func NewSequencer(service sointu.SynthService, iterator func() ([]Note, bool)) *Sequencer {
 	return &Sequencer{
-		synth:     synth,
+		service:   service,
 		iterator:  iterator,
-		rowLength: rowLength,
+		rowLength: math.MaxInt32,
 		rowTime:   math.MaxInt32,
 	}
 }
@@ -49,9 +49,6 @@ func NewSequencer(synth sointu.Synth, rowLength int, iterator func() ([]Note, bo
 func (s *Sequencer) ReadAudio(buffer []float32) (int, error) {
 	s.mutex.Lock()
 	defer s.mutex.Unlock()
-	if s.synth == nil {
-		return 0, errors.New("cannot Sequencer.ReadAudio; synth is nil")
-	}
 	totalRendered := 0
 	for i := 0; i < SEQUENCER_MAX_READ_TRIES; i++ {
 		gotRow := true
@@ -75,11 +72,21 @@ func (s *Sequencer) ReadAudio(buffer []float32) (int, error) {
 		if !gotRow {
 			rowTimeRemaining = math.MaxInt32
 		}
+		if s.synth != nil {
 			rendered, timeAdvanced, err := s.synth.Render(buffer[totalRendered*2:], rowTimeRemaining)
+			if err != nil {
+				s.synth = nil
+			}
 			totalRendered += rendered
 			s.rowTime += timeAdvanced
-		if err != nil {
+		} else {
-			return totalRendered * 2, fmt.Errorf("synth.Render failed: %v", err)
+			for totalRendered*2 < len(buffer) && rowTimeRemaining > 0 {
+				buffer[totalRendered*2] = 0
+				buffer[totalRendered*2+1] = 0
+				totalRendered++
+				s.rowTime++
+				rowTimeRemaining--
+			}
 		}
 		if totalRendered*2 >= len(buffer) {
 			return totalRendered * 2, nil
@@ -93,7 +100,9 @@ func (s *Sequencer) SetPatch(patch sointu.Patch) {
 	s.mutex.Lock()
 	if s.synth != nil {
 		s.synth.Update(patch)
-	} // TODO: what is s.synth is nil?
+	} else {
+		s.synth, _ = s.service.Compile(patch)
+	}
 	s.mutex.Unlock()
 }
 
@@ -119,9 +128,11 @@ func (s *Sequencer) Release(voice int) {
 
 // doNote is the internal trigger/release function that is not thread safe
 func (s *Sequencer) doNote(voice int, note byte) {
+	if s.synth != nil {
 		if note == 0 {
 			s.synth.Release(voice)
 		} else {
 			s.synth.Trigger(voice, note)
 		}
+	}
 }

tracker/tracker.go

@@ -9,7 +9,6 @@ import (
 	"gioui.org/widget"
 	"gioui.org/widget/material"
 	"github.com/vsariola/sointu"
-	"github.com/vsariola/sointu/bridge"
 )
 
 type Tracker struct {
@@ -70,7 +69,6 @@ type Tracker struct {
 	rowJump      chan int
 	patternJump  chan int
 	audioContext sointu.AudioContext
-	synth        sointu.Synth
 	playBuffer   []float32
 	closer       chan struct{}
 	undoStack    []sointu.Song
@@ -111,51 +109,17 @@ func (t *Tracker) TogglePlay() {
 func (t *Tracker) sequencerLoop(closer <-chan struct{}) {
 	output := t.audioContext.Output()
 	defer output.Close()
-	synth, err := bridge.Synth(t.song.Patch)
-	if err != nil {
-		panic("cannot create a synth with the default patch")
-	}
-	curVoices := make([]int, 32)
-	t.sequencer = NewSequencer(synth, t.song.SamplesPerRow(), func() ([]Note, bool) {
-		t.playRowPatMutex.Lock()
-		if !t.Playing {
-			t.playRowPatMutex.Unlock()
-			return nil, false
-		}
-		t.PlayPosition.Row++
-		t.PlayPosition.Wrap(t.song)
-		if t.NoteTracking {
-			t.Cursor.SongRow = t.PlayPosition
-			t.SelectionCorner.SongRow = t.PlayPosition
-		}
-		notes := make([]Note, 0, 32)
-		for track := range t.song.Tracks {
-			patternIndex := t.song.Tracks[track].Sequence[t.PlayPosition.Pattern]
-			note := t.song.Tracks[track].Patterns[patternIndex][t.PlayPosition.Row]
-			if note == 1 { // anything but hold causes an action.
-				continue
-			}
-			first := t.song.FirstTrackVoice(track)
-			notes = append(notes, Note{first + curVoices[track], 0})
-			if note > 1 {
-				curVoices[track]++
-				if curVoices[track] >= t.song.Tracks[track].NumVoices {
-					curVoices[track] = 0
-				}
-				notes = append(notes, Note{first + curVoices[track], note})
-			}
-		}
-		t.playRowPatMutex.Unlock()
-		t.ticked <- struct{}{}
-		return notes, true
-	})
 	buffer := make([]float32, 8192)
 	for {
 		select {
 		case <-closer:
 			return
 		default:
-			t.sequencer.ReadAudio(buffer)
+			read, _ := t.sequencer.ReadAudio(buffer)
+			for read < len(buffer) {
+				buffer[read] = 0
+				read++
+			}
 			output.WriteAudio(buffer)
 		}
 	}
@@ -448,7 +412,7 @@ func (t *Tracker) DeleteSelection() {
 	}
 }
 
-func New(audioContext sointu.AudioContext) *Tracker {
+func New(audioContext sointu.AudioContext, synthService sointu.SynthService) *Tracker {
 	t := &Tracker{
 		Theme:                 material.NewTheme(gofont.Collection()),
 		QuitButton:            new(widget.Clickable),
@@ -495,6 +459,40 @@ func New(audioContext sointu.AudioContext) *Tracker {
 	for range allUnits {
 		t.ChooseUnitTypeBtns = append(t.ChooseUnitTypeBtns, new(widget.Clickable))
 	}
+	curVoices := make([]int, 32)
+	t.sequencer = NewSequencer(synthService, func() ([]Note, bool) {
+		t.playRowPatMutex.Lock()
+		if !t.Playing {
+			t.playRowPatMutex.Unlock()
+			return nil, false
+		}
+		t.PlayPosition.Row++
+		t.PlayPosition.Wrap(t.song)
+		if t.NoteTracking {
+			t.Cursor.SongRow = t.PlayPosition
+			t.SelectionCorner.SongRow = t.PlayPosition
+		}
+		notes := make([]Note, 0, 32)
+		for track := range t.song.Tracks {
+			patternIndex := t.song.Tracks[track].Sequence[t.PlayPosition.Pattern]
+			note := t.song.Tracks[track].Patterns[patternIndex][t.PlayPosition.Row]
+			if note == 1 { // anything but hold causes an action.
+				continue
+			}
+			first := t.song.FirstTrackVoice(track)
+			notes = append(notes, Note{first + curVoices[track], 0})
+			if note > 1 {
+				curVoices[track]++
+				if curVoices[track] >= t.song.Tracks[track].NumVoices {
+					curVoices[track] = 0
+				}
+				notes = append(notes, Note{first + curVoices[track], note})
+			}
+		}
+		t.playRowPatMutex.Unlock()
+		t.ticked <- struct{}{}
+		return notes, true
+	})
 	go t.sequencerLoop(t.closer)
 	if err := t.LoadSong(defaultSong.Copy()); err != nil {
 		panic(fmt.Errorf("cannot load default song: %w", err))