feat(tracker): hook up audio to tracker, we have liftoff

audio still a bit crackly; should probably decouple actual row ticking and rendering of audio (but how does that work with tempo ops?)

sequencer goroutine is a bit weird, too, should rethink

go4k/tracker/tracker.go

@@ -1,8 +1,11 @@
 package tracker
 
 import (
+	"fmt"
 	"gioui.org/widget"
 	"github.com/vsariola/sointu/go4k"
+	"github.com/vsariola/sointu/go4k/audio"
+	"github.com/vsariola/sointu/go4k/bridge"
 )
 
 type Tracker struct {
@@ -11,14 +14,47 @@ type Tracker struct {
 	CursorRow      int
 	CursorColumn   int
 	DisplayPattern int
+	PlayPattern    int32
+	PlayRow        int32
 	ActiveTrack    int
 	CurrentOctave  byte
+	Playing        bool
+	ticked         chan struct{}
+	setPlaying     chan bool
+	rowJump        chan int
+	patternJump    chan int
+	player         audio.Player
+	synth          go4k.Synth
+	playBuffer     []float32
 }
 
-func New() *Tracker {
-	return &Tracker{
+func (t *Tracker) LoadSong(song go4k.Song) error {
+	if err := song.Validate(); err != nil {
+		return fmt.Errorf("invalid song: %w", err)
+	}
+	t.song = song
+	if synth, err := bridge.Synth(song.Patch); err != nil {
+		fmt.Println("error loading synth: %v", err)
+		t.synth = nil
+	} else {
+		t.synth = synth
+	}
+	return nil
+}
+
+func New(player audio.Player) *Tracker {
+	t := &Tracker{
 		QuitButton:    new(widget.Clickable),
 		CurrentOctave: 4,
-		song:          defaultSong,
+		player:        player,
+		setPlaying:    make(chan bool),
+		rowJump:       make(chan int),
+		patternJump:   make(chan int),
+		ticked:        make(chan struct{}),
 	}
+	go t.sequencerLoop()
+	if err := t.LoadSong(defaultSong); err != nil {
+		panic(fmt.Errorf("cannot load default song: %w", err))
+	}
+	return t
 }