audio: Refactoring: Unify loop

exp/audio/audio.go

@@ -15,7 +15,6 @@
 package audio
 
 import (
-	"fmt"
 	"io"
 	"runtime"
 	"sync"
@@ -121,9 +120,25 @@ func NewContext(sampleRate int) (*Context, error) {
 	c.stream = &mixedPlayersStream{
 		context: c,
 	}
-	if err := startPlaying(c.stream, c.sampleRate); err != nil {
-		return nil, fmt.Errorf("audio: NewContext error: %v", err)
+	p, err := newPlayer(c.stream, c.sampleRate)
+	if err != nil {
+		return nil, err
 	}
+	go func() {
+		// TODO: Is it OK to close asap?
+		defer p.close()
+		for {
+			err := p.proceed()
+			if err == io.EOF {
+				break
+			}
+			if err != nil {
+				// TODO: Record the last error
+				panic(err)
+			}
+			time.Sleep(1 * time.Millisecond)
+		}
+	}()
 	return c, nil
 }
 

exp/audio/audio_js.go

@@ -19,7 +19,6 @@ package audio
 import (
 	"errors"
 	"io"
-	"time"
 
 	"github.com/gopherjs/gopherjs/js"
 	"github.com/hajimehoshi/ebiten"
@@ -33,18 +32,13 @@ type player struct {
 	bufferSource      *js.Object
 }
 
-func startPlaying(src io.Reader, sampleRate int) error {
-	// Do nothing in node.js.
-	if js.Global.Get("require") != js.Undefined {
-		return nil
-	}
-
+func newPlayer(src io.Reader, sampleRate int) (*player, error) {
 	class := js.Global.Get("AudioContext")
 	if class == js.Undefined {
 		class = js.Global.Get("webkitAudioContext")
 	}
 	if class == js.Undefined {
-		return errors.New("audio: audio couldn't be initialized")
+		return nil, errors.New("audio: audio couldn't be initialized")
 	}
 	p := &player{
 		src:          src,
@@ -53,21 +47,7 @@ func startPlaying(src io.Reader, sampleRate int) error {
 		context:      class.New(),
 	}
 	p.positionInSamples = int64(p.context.Get("currentTime").Float() * float64(p.sampleRate))
-	go func() {
-		defer p.close()
-		for {
-			err := p.proceed()
-			if err == io.EOF {
-				break
-			}
-			if err != nil {
-				// TODO: Record the last error
-				panic(err)
-			}
-			time.Sleep(1 * time.Millisecond)
-		}
-	}()
-	return nil
+	return p, nil
 }
 
 func toLR(data []byte) ([]int16, []int16) {

exp/audio/audio_openal.go

@@ -40,13 +40,13 @@ type player struct {
 	isClosed   bool
 }
 
-func startPlaying(src io.Reader, sampleRate int) error {
+func newPlayer(src io.Reader, sampleRate int) (*player, error) {
 	if e := al.OpenDevice(); e != nil {
-		return fmt.Errorf("audio: OpenAL initialization failed: %v", e)
+		return nil, fmt.Errorf("audio: OpenAL initialization failed: %v", e)
 	}
 	s := al.GenSources(1)
 	if err := al.Error(); err != 0 {
-		return fmt.Errorf("audio: al.GenSources error: %d", err)
+		return nil, fmt.Errorf("audio: al.GenSources error: %d", err)
 	}
 	p := &player{
 		alSource:   s[0],
@@ -74,24 +74,7 @@ func startPlaying(src io.Reader, sampleRate int) error {
 		p.alBuffers = []al.Buffer{}
 	}
 	al.PlaySources(p.alSource)
-
-	go func() {
-		// TODO: Is it OK to close asap?
-		defer p.close()
-		for {
-			err := p.proceed()
-			if err == io.EOF {
-				break
-			}
-			if err != nil {
-				// TODO: Record the last error
-				panic(err)
-			}
-			//time.Sleep(1 * time.Second / ebiten.FPS / 2)
-			time.Sleep(1 * time.Millisecond)
-		}
-	}()
-	return nil
+	return p, nil
 }
 
 const (

exp/audio/audio_windows.go

@@ -28,7 +28,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"time"
 	"unsafe"
 )
 
@@ -86,7 +85,7 @@ type player struct {
 
 const bufferSize = 1024
 
-func startPlaying(src io.Reader, sampleRate int) error {
+func newPlayer(src io.Reader, sampleRate int) (*player, error) {
 	const numBlockAlign = channelNum * bitsPerSample / 8
 	f := C.WAVEFORMATEX{
 		wFormatTag:      C.WAVE_FORMAT_PCM,
@@ -98,7 +97,7 @@ func startPlaying(src io.Reader, sampleRate int) error {
 	}
 	var w C.HWAVEOUT
 	if err := C.waveOutOpen2(&w, &f); err != C.MMSYSERR_NOERROR {
-		return fmt.Errorf("audio: waveOutOpen error: %d", err)
+		return nil, fmt.Errorf("audio: waveOutOpen error: %d", err)
 	}
 	p := &player{
 		src:     src,
@@ -110,24 +109,10 @@ func startPlaying(src io.Reader, sampleRate int) error {
 		var err error
 		p.headers[i], err = newHeader(w, bufferSize)
 		if err != nil {
-			return err
+			return nil, err
 		}
 	}
-	go func() {
-		defer p.close()
-		for {
-			err := p.proceed()
-			if err == io.EOF {
-				break
-			}
-			if err != nil {
-				// TODO: Propagate this error?
-				panic(err)
-			}
-			time.Sleep(1 * time.Millisecond)
-		}
-	}()
-	return nil
+	return p, nil
 }
 
 func (p *player) proceed() error {