audio/internal/readerdriver: Use ALSA instead of PulseAudio

Updates #1633
Closes #1761
Updates #1766

.builds/alpine.yml

@@ -8,7 +8,6 @@ packages:
   - libxrandr-dev
   - mesa-dev
   - pkgconf
-  - pulseaudio-dev
   - go
 sources:
   - https://github.com/hajimehoshi/ebiten

.builds/arch.yml

@@ -1,8 +1,7 @@
 image: archlinux
 packages:
-  - alsa
+  - alsa-lib
   - libxcursor
-  - libpulse
   - libxi
   - libxinerama
   - libxrandr

.builds/debian.yml

@@ -4,7 +4,6 @@ packages:
   - libc6-dev
   - libglu1-mesa-dev
   - libgl1-mesa-dev
-  - libpulse-dev
   - libxcursor-dev
   - libxi-dev
   - libxinerama-dev

.builds/fedora.yml

@@ -9,7 +9,6 @@ packages:
   - mesa-libGLES-devel
   - mesa-libGLU-devel
   - pkg-config
-  - pulseaudio-libs-devel
   - go
 sources:
   - https://github.com/hajimehoshi/ebiten

.builds/ubuntu.yml

@@ -4,7 +4,6 @@ packages:
   - libc6-dev
   - libglu1-mesa-dev
   - libgl1-mesa-dev
-  - libpulse-dev
   - libxcursor-dev
   - libxi-dev
   - libxinerama-dev

.github/workflows/test.yml

@@ -35,7 +35,7 @@ jobs:
         if: ${{ matrix.os == 'ubuntu-latest' }}
         run: |
           sudo apt-get update
-          sudo apt-get install libasound2-dev libgl1-mesa-dev libpulse-dev libxcursor-dev libxi-dev libxinerama-dev libxrandr-dev libxxf86vm-dev
+          sudo apt-get install libasound2-dev libgl1-mesa-dev libxcursor-dev libxi-dev libxinerama-dev libxrandr-dev libxxf86vm-dev
 
       - name: Install wasmbrowsertest
         run: |

audio/internal/readerdriver/driver_unix.go

@@ -17,20 +17,14 @@
 
 package readerdriver
 
-// #cgo pkg-config: libpulse
-// #cgo LDFLAGS: -lpulse
+// #cgo pkg-config: alsa
 //
-// #include <pulse/pulseaudio.h>
-//
-// void ebiten_readerdriver_contextStateCallback(pa_context *context, void *userdata);
-// void ebiten_readerdriver_streamWriteCallback(pa_stream *stream, size_t requested_bytes, void *userdata);
-// void ebiten_readerdriver_streamStateCallback(pa_stream *stream, void *userdata);
-// void ebiten_readerdriver_streamSuccessCallback(pa_stream *stream, void *userdata);
+// #include <alsa/asoundlib.h>
 import "C"
 
 import (
 	"fmt"
-	"runtime"
+	"time"
 	"unsafe"
 )
 
@@ -43,16 +37,17 @@ type context struct {
 	channelNum      int
 	bitDepthInBytes int
 
-	mainloop *C.pa_threaded_mainloop
-	context  *C.pa_context
-	stream   *C.pa_stream
+	handle        *C.snd_pcm_t
+	supportsPause bool
 
 	players *players
 }
 
 var theContext *context
 
-const bufferSize = 4096
+func alsaError(err C.int) error {
+	return fmt.Errorf("readerdriver: ALSA error: %s", C.GoString(C.snd_strerror(err)))
+}
 
 func NewContext(sampleRate, channelNum, bitDepthInBytes int) (Context, chan struct{}, error) {
 	ready := make(chan struct{})
@@ -66,146 +61,126 @@ func NewContext(sampleRate, channelNum, bitDepthInBytes int) (Context, chan stru
 	}
 	theContext = c
 
-	c.mainloop = C.pa_threaded_mainloop_new()
-	if c.mainloop == nil {
-		return nil, nil, fmt.Errorf("readerdriver: pa_threaded_mainloop_new failed")
-	}
-	mainloopAPI := C.pa_threaded_mainloop_get_api(c.mainloop)
-	if mainloopAPI == nil {
-		return nil, nil, fmt.Errorf("readerdriver: pa_threaded_mainloop_get_api failed")
+	// Open a default ALSA audio device for blocking stream playback
+	cname := C.CString("default")
+	defer C.free(unsafe.Pointer(cname))
+	if err := C.snd_pcm_open(&c.handle, cname, C.SND_PCM_STREAM_PLAYBACK, 0); err < 0 {
+		return nil, nil, alsaError(err)
 	}
 
-	contextName := C.CString("pcm-playback")
-	defer C.free(unsafe.Pointer(contextName))
-	c.context = C.pa_context_new(mainloopAPI, contextName)
-	if c.context == nil {
-		return nil, nil, fmt.Errorf("readerdriver: pa_context_new failed")
+	periodSize := C.snd_pcm_uframes_t(1024)
+	bufferSize := periodSize * 2
+	if err := c.alsaPcmHwParams(sampleRate, channelNum, &bufferSize, &periodSize); err != nil {
+		return nil, nil, err
 	}
 
-	C.pa_context_set_state_callback(c.context, C.pa_context_notify_cb_t(C.ebiten_readerdriver_contextStateCallback), unsafe.Pointer(c.mainloop))
-
-	runtime.LockOSThread()
-	defer runtime.UnlockOSThread()
-	C.pa_threaded_mainloop_lock(c.mainloop)
-	defer C.pa_threaded_mainloop_unlock(c.mainloop)
-
-	if code := C.pa_threaded_mainloop_start(c.mainloop); code != 0 {
-		return nil, nil, fmt.Errorf("readerdriver: pa_threaded_mainloop_start failed: %s", C.GoString(C.pa_strerror(code)))
-	}
-	if code := C.pa_context_connect(c.context, nil, C.PA_CONTEXT_NOAUTOSPAWN, nil); code != 0 {
-		return nil, nil, fmt.Errorf("readerdriver: pa_context_connect failed: %s", C.GoString(C.pa_strerror(code)))
-	}
-
-	// Wait until the context is ready.
+	go func() {
+		buf32 := make([]float32, int(periodSize)*c.channelNum)
 		for {
-		contextState := C.pa_context_get_state(c.context)
-		if C.PA_CONTEXT_IS_GOOD(contextState) == 0 {
-			return nil, nil, fmt.Errorf("readerdriver: context state is bad")
+			if err := c.readAndWrite(buf32); err != nil {
+				panic(err)
 			}
-		if contextState == C.PA_CONTEXT_READY {
-			break
 		}
-		C.pa_threaded_mainloop_wait(c.mainloop)
-	}
-
-	sampleSpecificatiom := C.pa_sample_spec{
-		format:   C.PA_SAMPLE_FLOAT32LE,
-		rate:     C.uint(sampleRate),
-		channels: C.uchar(channelNum),
-	}
-	var m C.pa_channel_map
-	switch channelNum {
-	case 1:
-		C.pa_channel_map_init_mono(&m)
-	case 2:
-		C.pa_channel_map_init_stereo(&m)
-	}
-
-	streamName := C.CString("Playback")
-	defer C.free(unsafe.Pointer(streamName))
-	c.stream = C.pa_stream_new(c.context, streamName, &sampleSpecificatiom, &m)
-	C.pa_stream_set_state_callback(c.stream, C.pa_stream_notify_cb_t(C.ebiten_readerdriver_streamStateCallback), unsafe.Pointer(c.mainloop))
-	C.pa_stream_set_write_callback(c.stream, C.pa_stream_request_cb_t(C.ebiten_readerdriver_streamWriteCallback), nil)
-
-	const defaultValue = 0xffffffff
-	bufferAttr := C.pa_buffer_attr{
-		maxlength: defaultValue,
-		tlength:   bufferSize,
-		prebuf:    defaultValue,
-		minreq:    defaultValue,
-	}
-	var streamFlags C.pa_stream_flags_t = C.PA_STREAM_START_CORKED | C.PA_STREAM_INTERPOLATE_TIMING |
-		C.PA_STREAM_NOT_MONOTONIC | C.PA_STREAM_AUTO_TIMING_UPDATE |
-		C.PA_STREAM_ADJUST_LATENCY
-
-	if code := C.pa_stream_connect_playback(c.stream, nil, &bufferAttr, streamFlags, nil, nil); code != 0 {
-		return nil, nil, fmt.Errorf("readerdriver: pa_stream_connect_playback failed: %s", C.GoString(C.pa_strerror(code)))
-	}
-
-	// Wait until the stream is ready.
-	for {
-		streamState := C.pa_stream_get_state(c.stream)
-		if C.PA_STREAM_IS_GOOD(streamState) == 0 {
-			return nil, nil, fmt.Errorf("readerdriver: stream state is bad")
-		}
-		if streamState == C.PA_STREAM_READY {
-			break
-		}
-		C.pa_threaded_mainloop_wait(c.mainloop)
-	}
-
-	C.pa_stream_cork(c.stream, 0, C.pa_stream_success_cb_t(C.ebiten_readerdriver_streamSuccessCallback), unsafe.Pointer(c.mainloop))
+	}()
 
 	return c, ready, nil
 }
 
+func (c *context) alsaPcmHwParams(sampleRate, channelNum int, bufferSize, periodSize *C.snd_pcm_uframes_t) error {
+	var params *C.snd_pcm_hw_params_t
+	C.snd_pcm_hw_params_malloc(&params)
+	defer C.free(unsafe.Pointer(params))
+
+	if err := C.snd_pcm_hw_params_any(c.handle, params); err < 0 {
+		return alsaError(err)
+	}
+	if err := C.snd_pcm_hw_params_set_access(c.handle, params, C.SND_PCM_ACCESS_RW_INTERLEAVED); err < 0 {
+		return alsaError(err)
+	}
+	if err := C.snd_pcm_hw_params_set_format(c.handle, params, C.SND_PCM_FORMAT_FLOAT_LE); err < 0 {
+		return alsaError(err)
+	}
+	if err := C.snd_pcm_hw_params_set_channels(c.handle, params, C.unsigned(channelNum)); err < 0 {
+		return alsaError(err)
+	}
+	if err := C.snd_pcm_hw_params_set_rate_resample(c.handle, params, 1); err < 0 {
+		return alsaError(err)
+	}
+	sr := C.unsigned(sampleRate)
+	if err := C.snd_pcm_hw_params_set_rate_near(c.handle, params, &sr, nil); err < 0 {
+		return alsaError(err)
+	}
+	if err := C.snd_pcm_hw_params_set_buffer_size_near(c.handle, params, bufferSize); err < 0 {
+		return alsaError(err)
+	}
+	if err := C.snd_pcm_hw_params_set_period_size_near(c.handle, params, periodSize, nil); err < 0 {
+		return alsaError(err)
+	}
+	if err := C.snd_pcm_hw_params(c.handle, params); err < 0 {
+		return alsaError(err)
+	}
+	c.supportsPause = C.snd_pcm_hw_params_can_pause(params) == 1
+	return nil
+}
+
+func (c *context) readAndWrite(buf32 []float32) error {
+	for i := range buf32 {
+		buf32[i] = 0
+	}
+	c.players.read(buf32)
+
+	for len(buf32) > 0 {
+		n := C.snd_pcm_writei(c.handle, unsafe.Pointer(&buf32[0]), C.snd_pcm_uframes_t(len(buf32)/c.channelNum))
+		if n == -C.EPIPE {
+			// Underrun or overrun occurred.
+			if err := C.snd_pcm_prepare(c.handle); err < 0 {
+				return alsaError(err)
+			}
+			continue
+		}
+		if n < 0 {
+			return alsaError(C.int(n))
+		}
+		buf32 = buf32[int(n)*c.channelNum:]
+	}
+	return nil
+}
+
 func (c *context) Suspend() error {
-	C.pa_stream_cork(c.stream, 1, C.pa_stream_success_cb_t(C.ebiten_readerdriver_streamSuccessCallback), unsafe.Pointer(c.mainloop))
+	if c.supportsPause {
+		if err := C.snd_pcm_pause(c.handle, 1); err < 0 {
+			return alsaError(err)
+		}
+		return nil
+	}
+
+	if err := C.snd_pcm_drop(c.handle); err < 0 {
+		return alsaError(err)
+	}
 	return nil
 }
 
 func (c *context) Resume() error {
-	C.pa_stream_cork(c.stream, 0, C.pa_stream_success_cb_t(C.ebiten_readerdriver_streamSuccessCallback), unsafe.Pointer(c.mainloop))
+	if c.supportsPause {
+		if err := C.snd_pcm_pause(c.handle, 0); err < 0 {
+			return alsaError(err)
+		}
+		return nil
+	}
+
+try:
+	if err := C.snd_pcm_resume(c.handle); err < 0 {
+		if err == -C.EAGAIN {
+			time.Sleep(100 * time.Millisecond)
+			goto try
+		}
+		if err == -C.ENOSYS {
+			if err := C.snd_pcm_prepare(c.handle); err < 0 {
+				return alsaError(err)
+			}
+			return nil
+		}
+		return alsaError(err)
+	}
 	return nil
 }
-
-//export ebiten_readerdriver_contextStateCallback
-func ebiten_readerdriver_contextStateCallback(context *C.pa_context, mainloop unsafe.Pointer) {
-	C.pa_threaded_mainloop_signal((*C.pa_threaded_mainloop)(mainloop), 0)
-}
-
-//export ebiten_readerdriver_streamStateCallback
-func ebiten_readerdriver_streamStateCallback(stream *C.pa_stream, mainloop unsafe.Pointer) {
-	C.pa_threaded_mainloop_signal((*C.pa_threaded_mainloop)(mainloop), 0)
-}
-
-//export ebiten_readerdriver_streamSuccessCallback
-func ebiten_readerdriver_streamSuccessCallback(stream *C.pa_stream, userdata unsafe.Pointer) {
-}
-
-//export ebiten_readerdriver_streamWriteCallback
-func ebiten_readerdriver_streamWriteCallback(stream *C.pa_stream, requestedBytes C.size_t, userdata unsafe.Pointer) {
-	c := theContext
-
-	var buf unsafe.Pointer
-	var buf32 []float32
-	var bytesToFill C.size_t = bufferSize
-	for n := int(requestedBytes); n > 0; n -= int(bytesToFill) {
-		C.pa_stream_begin_write(stream, &buf, &bytesToFill)
-		if len(buf32) < int(bytesToFill)/4 {
-			buf32 = make([]float32, bytesToFill/4)
-		} else {
-			for i := 0; i < int(bytesToFill)/4; i++ {
-				buf32[i] = 0
-			}
-		}
-
-		c.players.read(buf32[:bytesToFill/4])
-
-		for i := uintptr(0); i < uintptr(bytesToFill/4); i++ {
-			*(*float32)(unsafe.Pointer(uintptr(buf) + 4*i)) = buf32[i]
-		}
-
-		C.pa_stream_write(stream, buf, bytesToFill, nil, 0, C.PA_SEEK_RELATIVE)
-	}
-}