set audio buffer size explicitly

cmd/rgnes/main.go

@@ -58,30 +58,40 @@ func (r *renderer) Refresh() {
 
 // ref: https://github.com/fogleman/nes/blob/3880f3400500b1ff2e89af4e12e90be46c73ae07/ui/audio.go#L5
 type Player struct {
-	stream         *portaudio.Stream
-	sampleRate     float64
-	outputChannels int
-	channel        chan float32
+	stream     *portaudio.Stream
+	sampleRate float64
+	channel    chan float32
 }
 
 func newPlayer() (*Player, error) {
 	host, err := portaudio.DefaultHostApi()
 	if err != nil {
 		return nil, err
 	}
-	parameters := portaudio.HighLatencyParameters(nil, host.DefaultOutputDevice)
+	outputChannels := 2
+	if host.DefaultOutputDevice.MaxOutputChannels < 2 {
+		outputChannels = host.DefaultOutputDevice.MaxOutputChannels
+	}
+	sampleRate := 48000.0
+	if host.DefaultOutputDevice.DefaultSampleRate < sampleRate {
+		sampleRate = host.DefaultOutputDevice.DefaultSampleRate
+
+	}
+	// This value was roughly determined.
+	// In the current implementation, if this value is too small or too large, the sound will be unexpected.
+	framesPerBuffer := 256
 
 	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),
+		sampleRate: sampleRate,
+		// This value was roughly determind too.
+		// In the current implementation, if this channel size is too large (e.g. 44100), the sound will be delayed.
+		channel: make(chan float32, 2048),
 	}
 
 	cbFunc := func(out []float32) {
 		var output float32
 		for i := range out {
-			if i%p.outputChannels == 0 {
+			if i%outputChannels == 0 {
 				select {
 				case sample := <-p.channel:
 					output = sample
@@ -92,7 +102,7 @@ func newPlayer() (*Player, error) {
 			out[i] = output
 		}
 	}
-	stream, err := portaudio.OpenStream(parameters, cbFunc)
+	stream, err := portaudio.OpenDefaultStream(0, outputChannels, sampleRate, framesPerBuffer, cbFunc)
 	if err != nil {
 		return nil, err
 	}