From b1ac141ea5e766ad611fad84991974b874c58787 Mon Sep 17 00:00:00 2001
From: Matias Lahti <matias@mixin.fi>
Date: Sun, 8 Nov 2020 04:27:52 +0200
Subject: [PATCH] fix(tracker/sequencer): add a way to exit the sequencer loop

---
 go4k/cmd/sointu-tracker/main.go | 4 +++-
 go4k/tracker/sequencer.go       | 4 +++-
 go4k/tracker/tracker.go         | 9 ++++++++-
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/go4k/cmd/sointu-tracker/main.go b/go4k/cmd/sointu-tracker/main.go
index 904c796..fe6c843 100644
--- a/go4k/cmd/sointu-tracker/main.go
+++ b/go4k/cmd/sointu-tracker/main.go
@@ -21,7 +21,9 @@ func main() {
 			app.Size(unit.Dp(800), unit.Dp(600)),
 			app.Title("Sointu Tracker"),
 		)
-		if err := tracker.New(plr).Run(w); err != nil {
+		t := tracker.New(plr)
+		defer t.Close()
+		if err := t.Run(w); err != nil {
 			fmt.Println(err)
 			os.Exit(1)
 		}
diff --git a/go4k/tracker/sequencer.go b/go4k/tracker/sequencer.go
index 2998dab..ec67367 100644
--- a/go4k/tracker/sequencer.go
+++ b/go4k/tracker/sequencer.go
@@ -12,7 +12,7 @@ func (t *Tracker) TogglePlay() {
 }
 
 // sequencerLoop is the main goroutine that handles the playing logic
-func (t *Tracker) sequencerLoop() {
+func (t *Tracker) sequencerLoop(closer chan struct{}) {
 	playing := false
 	rowTime := (time.Second * 60) / time.Duration(4*t.song.BPM)
 	tick := make(<-chan time.Time)
@@ -46,6 +46,8 @@ func (t *Tracker) sequencerLoop() {
 			atomic.StoreInt32(&t.PlayRow, int32(rowJump))
 		case patternJump := <-t.patternJump:
 			atomic.StoreInt32(&t.PlayPattern, int32(patternJump))
+		case <-closer:
+			return
 		case playState := <-t.setPlaying:
 			playing = playState
 			if playing {
diff --git a/go4k/tracker/tracker.go b/go4k/tracker/tracker.go
index d8eea35..e025081 100644
--- a/go4k/tracker/tracker.go
+++ b/go4k/tracker/tracker.go
@@ -26,6 +26,7 @@ type Tracker struct {
 	player         audio.Player
 	synth          go4k.Synth
 	playBuffer     []float32
+	closer         chan struct{}
 }
 
 func (t *Tracker) LoadSong(song go4k.Song) error {
@@ -42,6 +43,11 @@ func (t *Tracker) LoadSong(song go4k.Song) error {
 	return nil
 }
 
+func (t *Tracker) Close() {
+	t.player.Close()
+	t.closer <- struct{}{}
+}
+
 func New(player audio.Player) *Tracker {
 	t := &Tracker{
 		QuitButton:    new(widget.Clickable),
@@ -51,8 +57,9 @@ func New(player audio.Player) *Tracker {
 		rowJump:       make(chan int),
 		patternJump:   make(chan int),
 		ticked:        make(chan struct{}),
+		closer:        make(chan struct{}),
 	}
-	go t.sequencerLoop()
+	go t.sequencerLoop(t.closer)
 	if err := t.LoadSong(defaultSong); err != nil {
 		panic(fmt.Errorf("cannot load default song: %w", err))
 	}