audio: Remove channel argument from audio.Queue

example/audio/main.go

@@ -112,7 +112,7 @@ func addNote() {
 	vol := 1.0 / 16.0
 	square(l, vol, freq, 0.25)
 	square(r, vol, freq, 0.25)
-	audio.Queue(-1, toBytes(l, r))
+	audio.Queue(toBytes(l, r))
 }
 
 func update(screen *ebiten.Image) error {

example/piano/main.go

@@ -71,7 +71,7 @@ func toBytes(l, r []int16) []byte {
 func addNote(freq float64, vol float64) {
 	f := int(freq)
 	if n, ok := noteCache[f]; ok {
-		audio.Queue(-1, n)
+		audio.Queue(n)
 		return
 	}
 	length := len(pcm) * baseFreq / f
@@ -88,7 +88,7 @@ func addNote(freq float64, vol float64) {
 	}
 	n := toBytes(l, r)
 	noteCache[f] = n
-	audio.Queue(-1, n)
+	audio.Queue(n)
 }
 
 var keys = []ebiten.Key{

exp/audio/audio.go

@@ -28,16 +28,10 @@ const MaxChannel = audio.MaxChannel
 // The given data is queued to the end of the buffer.
 // This may not be played immediately when data already exists in the buffer.
 //
-// channel must be -1 or a channel index.
-// If channel is -1, an empty channel is automatically selected.
-//
-// If the channel is not empty, this function does nothing and returns false.
-// This returns true otherwise.
-//
 // data's format must be linear PCM (44100Hz, 16bits, 2 channel stereo, little endian)
 // without a header (e.g. RIFF header).
-func Queue(channel int, data []byte) bool {
-	return audio.Queue(channel, data)
+func Queue(data []byte) bool {
+	return audio.Queue(data)
 }
 
 // IsPlaying returns a boolean value which indicates if the channel buffer has data to play.

internal/audio/audio.go

@@ -70,14 +70,14 @@ func Tick() {
 }
 
 // TODO: Accept sample rate
-func Queue(channel int, data []byte) bool {
+func Queue(data []byte) bool {
 	result := true
 	withChannels(func() {
 		if !audioEnabled {
 			result = false
 			return
 		}
-		ch := channelAt(channel)
+		ch := channelAt(-1)
 		if ch == nil {
 			result = false
 			return

internal/audio/audio_js.go

@@ -28,8 +28,9 @@ var (
 )
 
 type audioProcessor struct {
-	channel  int
-	position float64
+	channel    int
+	sampleRate int
+	position   float64
 }
 
 var audioProcessors [MaxChannel]*audioProcessor
@@ -44,13 +45,13 @@ func toLR(data []byte) ([]int16, []int16) {
 	return l, r
 }
 
-func (a *audioProcessor) playChunk(buf []byte, sampleRate int) {
+func (a *audioProcessor) playChunk(buf []byte) {
 	if len(buf) == 0 {
 		return
 	}
 	const channelNum = 2
 	const bytesPerSample = channelNum * 16 / 8
-	b := context.Call("createBuffer", channelNum, len(buf)/bytesPerSample, sampleRate)
+	b := context.Call("createBuffer", channelNum, len(buf)/bytesPerSample, a.sampleRate)
 	l := b.Call("getChannelData", 0)
 	r := b.Call("getChannelData", 1)
 	il, ir := toLR(buf)
@@ -67,7 +68,7 @@ func (a *audioProcessor) playChunk(buf []byte, sampleRate int) {
 		a.position = c
 	}
 	s.Call("start", a.position)
-	a.position += float64(len(il)) / float64(sampleRate)
+	a.position += float64(len(il)) / float64(a.sampleRate)
 }
 
 func isPlaying(channel int) bool {
@@ -77,9 +78,8 @@ func isPlaying(channel int) bool {
 
 func tick() {
 	const bufferSize = 1024
-	const sampleRate = 44100 // TODO: This should be changeable
 	for _, a := range audioProcessors {
-		a.playChunk(loadChannelBuffer(a.channel, bufferSize*4), sampleRate)
+		a.playChunk(loadChannelBuffer(a.channel, bufferSize*4))
 	}
 }
 
@@ -100,8 +100,9 @@ func initialize() {
 	audioEnabled = true
 	for i := 0; i < len(audioProcessors); i++ {
 		audioProcessors[i] = &audioProcessor{
-			channel:  i,
-			position: 0,
+			channel:    i,
+			sampleRate: 44100, // TODO: Change this for each chunks
+			position:   0,
 		}
 	}
 }