fixed samplerate mismatch and bgm delay issue

cmd/rgnes/main.go

@@ -64,51 +64,57 @@ type Player struct {
 	channel        chan float32
 }
 
-func newPlayer() *Player {
-	a := Player{}
-	a.channel = make(chan float32, 44100)
-	return &a
-}
-
-func (a *Player) Start() error {
+func newPlayer() (*Player, error) {
 	host, err := portaudio.DefaultHostApi()
 	if err != nil {
-		return err
+		return nil, err
 	}
 	parameters := portaudio.HighLatencyParameters(nil, host.DefaultOutputDevice)
-	stream, err := portaudio.OpenStream(parameters, a.Callback)
-	if err != nil {
-		return err
+
+	p := Player{
+		sampleRate:     parameters.SampleRate,
+		outputChannels: parameters.Output.Channels,
+		// If this channel size is too large (e.g. 44100), the BGM will be delayed. Make the size not too big
+		channel: make(chan float32, 3000),
 	}
-	if err := stream.Start(); err != nil {
-		return err
+
+	cbFunc := func(out []float32) {
+		var output float32
+		for i := range out {
+			if i%p.outputChannels == 0 {
+				select {
+				case sample := <-p.channel:
+					output = sample
+				default:
+					output = 0
+				}
+			}
+			out[i] = output
+		}
 	}
-	a.stream = stream
-	a.sampleRate = parameters.SampleRate
-	a.outputChannels = parameters.Output.Channels
-	return nil
+	stream, err := portaudio.OpenStream(parameters, cbFunc)
+	if err != nil {
+		return nil, err
+	}
+
+	p.stream = stream
+	return &p, nil
 }
 
-func (a *Player) Stop() error {
-	return a.stream.Close()
+func (p *Player) Start() error {
+	return p.stream.Start()
 }
 
-func (a *Player) Callback(out []float32) {
-	var output float32
-	for i := range out {
-		if i%a.outputChannels == 0 {
-			select {
-			case sample := <-a.channel:
-				output = sample
-			default:
-				output = 0
-			}
-		}
-		out[i] = output
-	}
+func (p *Player) Stop() error {
+	return p.stream.Close()
 }
-func (a *Player) Sample(v float32) {
-	a.channel <- v
+
+func (p *Player) Sample(v float32) {
+	p.channel <- v
+}
+
+func (p *Player) SampleRate() float64 {
+	return p.sampleRate
 }
 
 func realMain() error {
@@ -149,7 +155,10 @@ func realMain() error {
 
 	portaudio.Initialize()
 	defer portaudio.Terminate()
-	player := newPlayer()
+	player, nil := newPlayer()
+	if err != nil {
+		return err
+	}
 	if err := player.Start(); err != nil {
 		return err
 	}

nes/apu.go

@@ -27,14 +27,13 @@ func init() {
 
 type Player interface {
 	Sample(float32)
+	SampleRate() float64
 }
 
-type APUOption func(*APU)
-
 type APU struct {
 	cpu          *interrupter
 	player       Player
-	sampleRate   int
+	sampleRate   float64
 	sampleTiming int
 	clock        int
 	pulse1       *pulse
@@ -53,11 +52,11 @@ type APU struct {
 	writeDelayFrameCounter byte
 }
 
-func NewAPU(cpu *interrupter, p Player, opts ...APUOption) *APU {
+func NewAPU(cpu *interrupter, p Player) *APU {
 	apu := &APU{
 		player:     p,
 		cpu:        cpu,
-		sampleRate: 44100,
+		sampleRate: p.SampleRate(),
 
 		clock:  -1,
 		pulse1: newPulse(1),
@@ -69,19 +68,10 @@ func NewAPU(cpu *interrupter, p Player, opts ...APUOption) *APU {
 		frameStep:          -1,
 		newFrameCounterVal: -1,
 	}
-	for _, opt := range opts {
-		opt(apu)
-	}
-	apu.sampleTiming = 1789773 / apu.sampleRate
+	apu.sampleTiming = int(1789773 / apu.sampleRate)
 	return apu
 }
 
-func WithSampleRate(sampleRate int) APUOption {
-	return func(apu *APU) {
-		apu.sampleRate = sampleRate
-	}
-}
-
 func (apu *APU) PowerUp() {
 	// todo
 	apu.writeStatus(0)

tests/cpu_test.go

@@ -17,7 +17,8 @@ func (f *fakeRenderer) Refresh()                       {}
 
 type fakePlayer struct{}
 
-func (f *fakePlayer) Sample(v float32) {}
+func (f *fakePlayer) Sample(v float32)    {}
+func (f *fakePlayer) SampleRate() float64 { return 44100 }
 
 func Test_CPU_OUT_6000(t *testing.T) {
 	t.Parallel()