audio: Refactoring

exp/audio/audio.go

@@ -19,8 +19,7 @@ import (
 )
 
 type Player struct {
-	src        io.ReadSeeker
-	sampleRate int
+	*player
 }
 
 // NewPlayer creates a new player with the given data to the given channel.
@@ -32,12 +31,9 @@ type Player struct {
 //
 // TODO: Pass sample rate and num of channels.
 func NewPlayer(src io.ReadSeeker, sampleRate int) *Player {
-	return &Player{
-		src:        src,
-		sampleRate: sampleRate,
-	}
+	return newPlayer(src, sampleRate)
 }
 
 func (p *Player) Play() error {
-	return play(p.src, p.sampleRate)
+	return p.play()
 }

exp/audio/audio_js.go

@@ -17,7 +17,6 @@
 package audio
 
 import (
-	"errors"
 	"io"
 	"io/ioutil"
 
@@ -26,12 +25,27 @@ import (
 
 var context *js.Object
 
-type audioProcessor struct {
+type player struct {
 	src        io.ReadSeeker
 	sampleRate int
 	position   float64
 }
 
+func newPlayer(src io.ReadSeeker, sampleRate int) *Player {
+	if context == nil {
+		if !initialize() {
+			panic("audio couldn't be initialized")
+		}
+	}
+
+	p := &player{
+		src:        src,
+		sampleRate: sampleRate,
+		position:   context.Get("currentTime").Float(),
+	}
+	return &Player{p}
+}
+
 func toLR(data []byte) ([]int16, []int16) {
 	l := make([]int16, len(data)/4)
 	r := make([]int16, len(data)/4)
@@ -42,9 +56,9 @@ func toLR(data []byte) ([]int16, []int16) {
 	return l, r
 }
 
-func (a *audioProcessor) play() error {
+func (p *player) play() error {
 	// TODO: Reading all data at once is temporary implemntation. Treat this as stream.
-	buf, err := ioutil.ReadAll(a.src)
+	buf, err := ioutil.ReadAll(p.src)
 	if err != nil {
 		return err
 	}
@@ -53,7 +67,7 @@ func (a *audioProcessor) play() error {
 	}
 	const channelNum = 2
 	const bytesPerSample = channelNum * 16 / 8
-	b := context.Call("createBuffer", channelNum, len(buf)/bytesPerSample, a.sampleRate)
+	b := context.Call("createBuffer", channelNum, len(buf)/bytesPerSample, p.sampleRate)
 	l := b.Call("getChannelData", 0)
 	r := b.Call("getChannelData", 1)
 	il, ir := toLR(buf)
@@ -65,25 +79,11 @@ func (a *audioProcessor) play() error {
 	s := context.Call("createBufferSource")
 	s.Set("buffer", b)
 	s.Call("connect", context.Get("destination"))
-	s.Call("start", a.position)
-	a.position += b.Get("duration").Float()
+	s.Call("start", p.position)
+	p.position += b.Get("duration").Float()
 	return nil
 }
 
-func play(src io.ReadSeeker, sampleRate int) error {
-	if context == nil {
-		if !initialize() {
-			return errors.New("audio couldn't be initialized")
-		}
-	}
-	a := &audioProcessor{
-		src:        src,
-		sampleRate: sampleRate,
-		position:   context.Get("currentTime").Float(),
-	}
-	return a.play()
-}
-
 func initialize() bool {
 	// Do nothing in node.js.
 	if js.Global.Get("require") != js.Undefined {

exp/audio/audio_openal.go

@@ -30,13 +30,23 @@ func (r *readSeekCloser) Close() error {
 	return nil
 }
 
-func play(src io.ReadSeeker, sampleRate int) error {
-	// TODO: audio.NewPlayer interprets WAV header, which we don't want.
-	// Use OpenAL or native API instead.
+type player struct {
+	*audio.Player
+}
+
+func newPlayer(src io.ReadSeeker, sampleRate int) *Player {
 	p, err := audio.NewPlayer(&readSeekCloser{src}, audio.Stereo16, int64(sampleRate))
 	if err != nil {
-		return err
+		// TODO: Should we return errors for this method?
+		panic(err)
 	}
+	pp := &player{p}
+	return &Player{pp}
+}
+
+func (p *player) play() error {
+	// TODO: audio.NewPlayer interprets WAV header, which we don't want.
+	// Use OpenAL or native API instead.
 	return p.Play()
 }