audio: Use IO as source

example/audio/main.go

@@ -15,6 +15,7 @@
 package main
 
 import (
+	"bytes"
 	"fmt"
 	"log"
 	"math"
@@ -85,6 +86,13 @@ func toBytes(l, r []int16) []byte {
 	return b
 }
 
+type stream struct {
+	*bytes.Reader
+}
+
+func (s *stream) Close() error {
+	return nil
+}
 func addNote() {
 	size := sampleRate / 60
 	notes := []float64{freqC, freqD, freqE, freqF, freqG, freqA * 2, freqB * 2}
@@ -113,7 +121,8 @@ func addNote() {
 	vol := 1.0 / 16.0
 	square(l, vol, freq, 0.25)
 	square(r, vol, freq, 0.25)
-	audio.Queue(toBytes(l, r), sampleRate)
+	b := toBytes(l, r)
+	audio.Queue(&stream{bytes.NewReader(b)}, sampleRate)
 }
 
 func update(screen *ebiten.Image) error {

example/piano/main.go

@@ -15,6 +15,7 @@
 package main
 
 import (
+	"bytes"
 	"fmt"
 	"image/color"
 	"log"
@@ -69,10 +70,18 @@ func toBytes(l, r []int16) []byte {
 	return b
 }
 
+type stream struct {
+	*bytes.Reader
+}
+
+func (s *stream) Close() error {
+	return nil
+}
+
 func addNote(freq float64, vol float64) {
 	f := int(freq)
 	if n, ok := noteCache[f]; ok {
-		audio.Queue(n, sampleRate)
+		audio.Queue(&stream{bytes.NewReader(n)}, sampleRate)
 		return
 	}
 	length := len(pcm) * baseFreq / f
@@ -89,7 +98,7 @@ func addNote(freq float64, vol float64) {
 	}
 	n := toBytes(l, r)
 	noteCache[f] = n
-	audio.Queue(n, sampleRate)
+	audio.Queue(&stream{bytes.NewReader(n)}, sampleRate)
 }
 
 var keys = []ebiten.Key{

exp/audio/audio.go

@@ -15,19 +15,24 @@
 package audio
 
 import (
+	"io"
+
 	"github.com/hajimehoshi/ebiten/internal/audio"
 )
 
+type ReadSeekCloser interface {
+	io.ReadSeeker
+	io.Closer
+}
+
 // Queue queues the given data to the given channel.
 // The given data is queued to the end of the buffer.
 // This may not be played immediately when data already exists in the buffer.
 //
-// data's format must be linear PCM (16bits, 2 channel stereo, little endian)
+// src's format must be linear PCM (16bits, 2 channel stereo, little endian)
 // without a header (e.g. RIFF header).
 //
 // TODO: Pass sample rate and num of channels.
-func Queue(data []byte, sampleRate int) error {
-	return audio.Queue(data, sampleRate)
+func Queue(src ReadSeekCloser, sampleRate int) error {
+	return audio.Queue(src, sampleRate)
 }
-
-// TODO: Add Clear function

internal/audio/audio.go

@@ -14,16 +14,26 @@
 
 package audio
 
+import (
+	"io"
+)
+
 var audioEnabled = false
 
+type ReadSeekCloser interface {
+	io.ReadSeeker
+	io.Closer
+}
+
 type chunk struct {
-	buffer     []byte
+	buffer     ReadSeekCloser
 	sampleRate int
 }
 
 func Init() {
 	initialize()
 }
-func Queue(data []byte, sampleRate int) error {
-	return playChunk(data, sampleRate)
+
+func Queue(src ReadSeekCloser, sampleRate int) error {
+	return playChunk(src, sampleRate)
 }

internal/audio/audio_js.go

@@ -17,13 +17,15 @@
 package audio
 
 import (
+	"io/ioutil"
+
 	"github.com/gopherjs/gopherjs/js"
 )
 
 var context *js.Object
 
 type audioProcessor struct {
-	data       []byte
+	src        ReadSeekCloser
 	sampleRate int
 	position   float64
 }
@@ -38,9 +40,14 @@ func toLR(data []byte) ([]int16, []int16) {
 	return l, r
 }
 
-func (a *audioProcessor) playChunk(buf []byte) {
+func (a *audioProcessor) play() error {
+	// TODO: Reading all data at once is temporary implemntation. Treat this as stream.
+	buf, err := ioutil.ReadAll(a.src)
+	if err != nil {
+		return err
+	}
 	if len(buf) == 0 {
-		return
+		return nil
 	}
 	const channelNum = 2
 	const bytesPerSample = channelNum * 16 / 8
@@ -58,17 +65,16 @@ func (a *audioProcessor) playChunk(buf []byte) {
 	s.Call("connect", context.Get("destination"))
 	s.Call("start", a.position)
 	a.position += b.Get("duration").Float()
+	return nil
 }
 
-// TOOD: Implement IO version
-func playChunk(data []byte, sampleRate int) error {
+func playChunk(src ReadSeekCloser, sampleRate int) error {
 	a := &audioProcessor{
-		data:       data,
+		src:        src,
 		sampleRate: sampleRate,
 		position:   context.Get("currentTime").Float(),
 	}
-	a.playChunk(data)
-	return nil
+	return a.play()
 }
 
 func initialize() {

internal/audio/audio_openal.go

@@ -17,25 +17,17 @@
 package audio
 
 import (
-	"bytes"
 	"time"
 
 	"golang.org/x/mobile/exp/audio"
 )
 
-type src struct {
-	*bytes.Reader
-}
-
-func (s *src) Close() error {
-	return nil
-}
-
 var players = map[*audio.Player]struct{}{}
 
-func playChunk(data []byte, sampleRate int) error {
-	s := &src{bytes.NewReader(data)}
-	p, err := audio.NewPlayer(s, audio.Stereo16, int64(sampleRate))
+func playChunk(src ReadSeekCloser, sampleRate int) error {
+	// TODO: audio.NewPlayer interprets WAV header, which we don't want.
+	// Use OpenAL or native API instead.
+	p, err := audio.NewPlayer(src, audio.Stereo16, int64(sampleRate))
 	if err != nil {
 		return err
 	}