audio: Move drivers to internal/driver

exp/audio/audio.go

@@ -21,6 +21,7 @@ import (
 	"time"
 
 	"github.com/hajimehoshi/ebiten"
+	"github.com/hajimehoshi/ebiten/exp/audio/internal/driver"
 )
 
 type mixingStream struct {
@@ -44,7 +45,6 @@ func min(a, b int) int {
 const (
 	channelNum     = 2
 	bytesPerSample = 2
-	bitsPerSample  = bytesPerSample * 8
 
 	// TODO: This assumes that channelNum is a power of 2.
 	mask = ^(channelNum*bytesPerSample - 1)
@@ -197,15 +197,15 @@ func NewContext(sampleRate int) (*Context, error) {
 		players:    map[*Player]struct{}{},
 	}
 	// TODO: Rename this other than player
-	p, err := newPlayer(c.stream, sampleRate)
+	p, err := driver.NewPlayer(c.stream, sampleRate, channelNum, bytesPerSample)
 	if err != nil {
 		return nil, err
 	}
 	go func() {
 		// TODO: Is it OK to close asap?
-		defer p.close()
+		defer p.Close()
 		for {
-			err := p.proceed()
+			err := p.Proceed()
 			if err == io.EOF {
 				break
 			}

exp/audio/internal/driver/driver_js.go

@@ -14,25 +14,26 @@
 
 // +build js
 
-package audio
+package driver
 
 import (
 	"errors"
 	"io"
 
 	"github.com/gopherjs/gopherjs/js"
-	"github.com/hajimehoshi/ebiten"
 )
 
-type player struct {
+type Player struct {
 	src               io.Reader
 	sampleRate        int
+	channelNum        int
+	bytesPerSample    int
 	positionInSamples int64
 	context           *js.Object
 	bufferSource      *js.Object
 }
 
-func newPlayer(src io.Reader, sampleRate int) (*player, error) {
+func NewPlayer(src io.Reader, sampleRate, channelNum, bytesPerSample int) (*Player, error) {
 	class := js.Global.Get("AudioContext")
 	if class == js.Undefined {
 		class = js.Global.Get("webkitAudioContext")
@@ -40,9 +41,11 @@ func newPlayer(src io.Reader, sampleRate int) (*player, error) {
 	if class == js.Undefined {
 		return nil, errors.New("audio: audio couldn't be initialized")
 	}
-	p := &player{
+	p := &Player{
 		src:            src,
 		sampleRate:     sampleRate,
+		channelNum:     channelNum,
+		bytesPerSample: bytesPerSample,
 		bufferSource:   nil,
 		context:        class.New(),
 	}
@@ -67,8 +70,12 @@ func max64(a, b int64) int64 {
 	return b
 }
 
-func (p *player) proceed() error {
-	bufferSize := p.sampleRate * bytesPerSample * channelNum / ebiten.FPS
+const (
+	// 1024 seems not enough (some noise remains after the tab is deactivated).
+	bufferSize = 2048
+)
+
+func (p *Player) Proceed() error {
 	c := int64(p.context.Get("currentTime").Float() * float64(p.sampleRate))
 	if p.positionInSamples < c {
 		p.positionInSamples = c
@@ -76,7 +83,7 @@ func (p *player) proceed() error {
 	b := make([]byte, bufferSize)
 	n, err := p.src.Read(b)
 	if 0 < n {
-		buf := p.context.Call("createBuffer", channelNum, n/bytesPerSample/channelNum, p.sampleRate)
+		buf := p.context.Call("createBuffer", p.channelNum, n/p.bytesPerSample/p.channelNum, p.sampleRate)
 		l := buf.Call("getChannelData", 0)
 		r := buf.Call("getChannelData", 1)
 		il, ir := toLR(b[:n])
@@ -96,7 +103,7 @@ func (p *player) proceed() error {
 	return err
 }
 
-func (p *player) close() error {
+func (p *Player) Close() error {
 	if p.bufferSource == nil {
 		return nil
 	}

exp/audio/internal/driver/driver_openal.go

@@ -14,7 +14,7 @@
 
 // +build !js,!windows
 
-package audio
+package driver
 
 import (
 	"fmt"
@@ -28,7 +28,7 @@ const (
 	maxBufferNum = 8
 )
 
-type player struct {
+type Player struct {
 	alSource   al.Source
 	alBuffers  []al.Buffer
 	source     io.Reader
@@ -36,7 +36,7 @@ type player struct {
 	isClosed   bool
 }
 
-func newPlayer(src io.Reader, sampleRate int) (*player, error) {
+func NewPlayer(src io.Reader, sampleRate, channelNum, bytesPerSample int) (*Player, error) {
 	if e := al.OpenDevice(); e != nil {
 		return nil, fmt.Errorf("audio: OpenAL initialization failed: %v", e)
 	}
@@ -44,13 +44,13 @@ func newPlayer(src io.Reader, sampleRate int) (*player, error) {
 	if err := al.Error(); err != 0 {
 		return nil, fmt.Errorf("audio: al.GenSources error: %d", err)
 	}
-	p := &player{
+	p := &Player{
 		alSource:   s[0],
 		alBuffers:  []al.Buffer{},
 		source:     src,
 		sampleRate: sampleRate,
 	}
-	runtime.SetFinalizer(p, (*player).close)
+	runtime.SetFinalizer(p, (*Player).Close)
 
 	bs := al.GenBuffers(maxBufferNum)
 	emptyBytes := make([]byte, bufferSize)
@@ -72,7 +72,7 @@ var (
 	tmpAlBuffers = make([]al.Buffer, maxBufferNum)
 )
 
-func (p *player) proceed() error {
+func (p *Player) Proceed() error {
 	if err := al.Error(); err != 0 {
 		return fmt.Errorf("audio: before proceed: %d", err)
 	}
@@ -113,7 +113,7 @@ func (p *player) proceed() error {
 	return nil
 }
 
-func (p *player) close() error {
+func (p *Player) Close() error {
 	if err := al.Error(); err != 0 {
 		return fmt.Errorf("audio: error before closing: %d", err)
 	}

exp/audio/internal/driver/driver_windows.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package audio
+package driver
 
 // #cgo LDFLAGS: -lwinmm
 //
@@ -75,7 +75,7 @@ func releaseSemaphore() {
 	<-sem
 }
 
-type player struct {
+type Player struct {
 	src     io.Reader
 	out     C.HWAVEOUT
 	buffer  []byte
@@ -84,21 +84,21 @@ type player struct {
 
 const bufferSize = 1024
 
-func newPlayer(src io.Reader, sampleRate int) (*player, error) {
-	const numBlockAlign = channelNum * bitsPerSample / 8
+func NewPlayer(src io.Reader, sampleRate, channelNum, bytesPerSample int) (*Player, error) {
+	const numBlockAlign = channelNum * bytesPerSample
 	f := C.WAVEFORMATEX{
 		wFormatTag:      C.WAVE_FORMAT_PCM,
 		nChannels:       channelNum,
 		nSamplesPerSec:  C.DWORD(sampleRate),
 		nAvgBytesPerSec: C.DWORD(sampleRate) * numBlockAlign,
-		wBitsPerSample:  bitsPerSample,
+		wBitsPerSample:  bytesPerSample * 8,
 		nBlockAlign:     numBlockAlign,
 	}
 	var w C.HWAVEOUT
 	if err := C.waveOutOpen2(&w, &f); err != C.MMSYSERR_NOERROR {
 		return nil, fmt.Errorf("audio: waveOutOpen error: %d", err)
 	}
-	p := &player{
+	p := &Player{
 		src:     src,
 		out:     w,
 		buffer:  []byte{},
@@ -114,7 +114,7 @@ func newPlayer(src io.Reader, sampleRate int) (*player, error) {
 	return p, nil
 }
 
-func (p *player) proceed() error {
+func (p *Player) Proceed() error {
 	if len(p.buffer) < bufferSize {
 		b := make([]byte, bufferSize)
 		n, err := p.src.Read(b)
@@ -146,6 +146,6 @@ func (p *player) proceed() error {
 	return nil
 }
 
-func (p *player) close() {
+func (p *Player) Close() {
 	// TODO: Implement this
 }