static int Audio_Available(void)
{
int available;
int status;
snd_pcm_t *handle;
available = 0;
status = snd_pcm_open(&handle, get_audio_device(), SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
if ( status >= 0 ) {
available = 1;
snd_pcm_close(handle);
}
return(available);
}
static int Audio_Available(void)
{
int available;
int status;
snd_pcm_t *handle;
available = 0;
if (LoadALSALibrary() < 0) {
return available;
}
status = SDL_NAME(snd_pcm_open)(&handle, get_audio_device(2), SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
if ( status >= 0 ) {
available = 1;
SDL_NAME(snd_pcm_close)(handle);
}
UnloadALSALibrary();
return(available);
}
static int ALSA_OpenAudio(_THIS, SDL_AudioSpec *spec)
{
int status;
snd_pcm_hw_params_t *hwparams;
snd_pcm_sw_params_t *swparams;
snd_pcm_format_t format;
snd_pcm_uframes_t frames;
Uint16 test_format;
/* Open the audio device */
/* Name of device should depend on # channels in spec */
status = SDL_NAME(snd_pcm_open)(&pcm_handle, get_audio_device(spec->channels), SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
if ( status < 0 ) {
SDL_SetError("Couldn't open audio device: %s", SDL_NAME(snd_strerror)(status));
return(-1);
}
/* Figure out what the hardware is capable of */
snd_pcm_hw_params_alloca(&hwparams);
status = SDL_NAME(snd_pcm_hw_params_any)(pcm_handle, hwparams);
if ( status < 0 ) {
SDL_SetError("Couldn't get hardware config: %s", SDL_NAME(snd_strerror)(status));
ALSA_CloseAudio(this);
return(-1);
}
/* SDL only uses interleaved sample output */
status = SDL_NAME(snd_pcm_hw_params_set_access)(pcm_handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED);
if ( status < 0 ) {
SDL_SetError("Couldn't set interleaved access: %s", SDL_NAME(snd_strerror)(status));
ALSA_CloseAudio(this);
return(-1);
}
/* Try for a closest match on audio format */
status = -1;
for ( test_format = SDL_FirstAudioFormat(spec->format);
test_format && (status < 0); ) {
switch ( test_format ) {
case AUDIO_U8:
format = SND_PCM_FORMAT_U8;
break;
case AUDIO_S8:
format = SND_PCM_FORMAT_S8;
break;
case AUDIO_S16LSB:
format = SND_PCM_FORMAT_S16_LE;
break;
case AUDIO_S16MSB:
format = SND_PCM_FORMAT_S16_BE;
break;
case AUDIO_U16LSB:
format = SND_PCM_FORMAT_U16_LE;
break;
case AUDIO_U16MSB:
format = SND_PCM_FORMAT_U16_BE;
break;
default:
format = 0;
break;
}
if ( format != 0 ) {
status = SDL_NAME(snd_pcm_hw_params_set_format)(pcm_handle, hwparams, format);
}
if ( status < 0 ) {
test_format = SDL_NextAudioFormat();
}
}
if ( status < 0 ) {
SDL_SetError("Couldn't find any hardware audio formats");
ALSA_CloseAudio(this);
return(-1);
}
spec->format = test_format;
/* Set the number of channels */
status = SDL_NAME(snd_pcm_hw_params_set_channels)(pcm_handle, hwparams, spec->channels);
if ( status < 0 ) {
status = SDL_NAME(snd_pcm_hw_params_get_channels)(hwparams);
if ( (status <= 0) || (status > 2) ) {
SDL_SetError("Couldn't set audio channels");
ALSA_CloseAudio(this);
return(-1);
}
spec->channels = status;
}
/* Set the audio rate */
status = SDL_NAME(snd_pcm_hw_params_set_rate_near)(pcm_handle, hwparams, spec->freq, NULL);
if ( status < 0 ) {
SDL_SetError("Couldn't set audio frequency: %s", SDL_NAME(snd_strerror)(status));
ALSA_CloseAudio(this);
return(-1);
}
spec->freq = status;
/* Set the buffer size, in samples */
frames = spec->samples;
frames = SDL_NAME(snd_pcm_hw_params_set_period_size_near)(pcm_handle, hwparams, frames, NULL);
spec->samples = frames;
SDL_NAME(snd_pcm_hw_params_set_periods_near)(pcm_handle, hwparams, 2, NULL);
/* "set" the hardware with the desired parameters */
status = SDL_NAME(snd_pcm_hw_params)(pcm_handle, hwparams);
if ( status < 0 ) {
SDL_SetError("Couldn't set hardware audio parameters: %s", SDL_NAME(snd_strerror)(status));
ALSA_CloseAudio(this);
return(-1);
}
/* This is useful for debugging... */
/*
{ snd_pcm_sframes_t bufsize; int fragments;
bufsize = SDL_NAME(snd_pcm_hw_params_get_period_size)(hwparams);
fragments = SDL_NAME(snd_pcm_hw_params_get_periods)(hwparams);
fprintf(stderr, "ALSA: bufsize = %ld, fragments = %d\n", bufsize, fragments);
}
*/
/* Set the software parameters */
snd_pcm_sw_params_alloca(&swparams);
status = SDL_NAME(snd_pcm_sw_params_current)(pcm_handle, swparams);
if ( status < 0 ) {
SDL_SetError("Couldn't get software config: %s", SDL_NAME(snd_strerror)(status));
ALSA_CloseAudio(this);
return(-1);
}
status = SDL_NAME(snd_pcm_sw_params_set_start_threshold)(pcm_handle, swparams, 0);
if ( status < 0 ) {
SDL_SetError("Couldn't set start threshold: %s", SDL_NAME(snd_strerror)(status));
ALSA_CloseAudio(this);
return(-1);
}
status = SDL_NAME(snd_pcm_sw_params_set_avail_min)(pcm_handle, swparams, frames);
if ( status < 0 ) {
SDL_SetError("Couldn't set avail min: %s", SDL_NAME(snd_strerror)(status));
ALSA_CloseAudio(this);
return(-1);
}
status = SDL_NAME(snd_pcm_sw_params)(pcm_handle, swparams);
if ( status < 0 ) {
SDL_SetError("Couldn't set software audio parameters: %s", SDL_NAME(snd_strerror)(status));
ALSA_CloseAudio(this);
return(-1);
}
/* Calculate the final parameters for this audio specification */
SDL_CalculateAudioSpec(spec);
/* Allocate mixing buffer */
mixlen = spec->size;
mixbuf = (Uint8 *)SDL_AllocAudioMem(mixlen);
if ( mixbuf == NULL ) {
ALSA_CloseAudio(this);
return(-1);
}
SDL_memset(mixbuf, spec->silence, spec->size);
/* Get the parent process id (we're the parent of the audio thread) */
parent = getpid();
/* Switch to blocking mode for playback */
SDL_NAME(snd_pcm_nonblock)(pcm_handle, 0);
/* We're ready to rock and roll. :-) */
return(0);
}
static int
ALSA_OpenDevice(_THIS, const char *devname, int iscapture)
{
int status = 0;
snd_pcm_t *pcm_handle = NULL;
snd_pcm_hw_params_t *hwparams = NULL;
snd_pcm_sw_params_t *swparams = NULL;
snd_pcm_format_t format = 0;
snd_pcm_uframes_t frames = 0;
SDL_AudioFormat test_format = 0;
/* Initialize all variables that we clean on shutdown */
this->hidden = (struct SDL_PrivateAudioData *)
SDL_malloc((sizeof *this->hidden));
if (this->hidden == NULL) {
SDL_OutOfMemory();
return 0;
}
SDL_memset(this->hidden, 0, (sizeof *this->hidden));
/* Open the audio device */
/* Name of device should depend on # channels in spec */
status = ALSA_snd_pcm_open(&pcm_handle,
get_audio_device(this->spec.channels),
SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
if (status < 0) {
ALSA_CloseDevice(this);
SDL_SetError("ALSA: Couldn't open audio device: %s",
ALSA_snd_strerror(status));
return 0;
}
this->hidden->pcm_handle = pcm_handle;
/* Figure out what the hardware is capable of */
snd_pcm_hw_params_alloca(&hwparams);
status = ALSA_snd_pcm_hw_params_any(pcm_handle, hwparams);
if (status < 0) {
ALSA_CloseDevice(this);
SDL_SetError("ALSA: Couldn't get hardware config: %s",
ALSA_snd_strerror(status));
return 0;
}
/* SDL only uses interleaved sample output */
status = ALSA_snd_pcm_hw_params_set_access(pcm_handle, hwparams,
SND_PCM_ACCESS_RW_INTERLEAVED);
if (status < 0) {
ALSA_CloseDevice(this);
SDL_SetError("ALSA: Couldn't set interleaved access: %s",
ALSA_snd_strerror(status));
return 0;
}
/* Try for a closest match on audio format */
status = -1;
for (test_format = SDL_FirstAudioFormat(this->spec.format);
test_format && (status < 0);) {
status = 0; /* if we can't support a format, it'll become -1. */
switch (test_format) {
case AUDIO_U8:
format = SND_PCM_FORMAT_U8;
break;
case AUDIO_S8:
format = SND_PCM_FORMAT_S8;
break;
case AUDIO_S16LSB:
format = SND_PCM_FORMAT_S16_LE;
break;
case AUDIO_S16MSB:
format = SND_PCM_FORMAT_S16_BE;
break;
case AUDIO_U16LSB:
format = SND_PCM_FORMAT_U16_LE;
break;
case AUDIO_U16MSB:
format = SND_PCM_FORMAT_U16_BE;
break;
case AUDIO_S32LSB:
format = SND_PCM_FORMAT_S32_LE;
break;
case AUDIO_S32MSB:
format = SND_PCM_FORMAT_S32_BE;
break;
case AUDIO_F32LSB:
format = SND_PCM_FORMAT_FLOAT_LE;
break;
case AUDIO_F32MSB:
format = SND_PCM_FORMAT_FLOAT_BE;
break;
default:
status = -1;
break;
}
if (status >= 0) {
status = ALSA_snd_pcm_hw_params_set_format(pcm_handle,
hwparams, format);
}
if (status < 0) {
test_format = SDL_NextAudioFormat();
}
}
if (status < 0) {
ALSA_CloseDevice(this);
SDL_SetError("ALSA: Couldn't find any hardware audio formats");
return 0;
}
this->spec.format = test_format;
/* Set the number of channels */
status = ALSA_snd_pcm_hw_params_set_channels(pcm_handle, hwparams,
this->spec.channels);
if (status < 0) {
status = ALSA_snd_pcm_hw_params_get_channels(hwparams);
if ((status <= 0) || (status > 2)) {
ALSA_CloseDevice(this);
SDL_SetError("ALSA: Couldn't set audio channels");
return 0;
}
this->spec.channels = status;
}
/* Set the audio rate */
status = ALSA_snd_pcm_hw_params_set_rate_near(pcm_handle, hwparams,
this->spec.freq, NULL);
if (status < 0) {
ALSA_CloseDevice(this);
SDL_SetError("ALSA: Couldn't set audio frequency: %s",
ALSA_snd_strerror(status));
return 0;
}
this->spec.freq = status;
/* Set the buffer size, in samples */
frames = this->spec.samples;
frames = ALSA_snd_pcm_hw_params_set_period_size_near(pcm_handle, hwparams,
frames, NULL);
this->spec.samples = frames;
ALSA_snd_pcm_hw_params_set_periods_near(pcm_handle, hwparams, 2, NULL);
/* "set" the hardware with the desired parameters */
status = ALSA_snd_pcm_hw_params(pcm_handle, hwparams);
if (status < 0) {
ALSA_CloseDevice(this);
SDL_SetError("ALSA: Couldn't set hardware audio parameters: %s",
ALSA_snd_strerror(status));
return 0;
}
#if AUDIO_DEBUG
{
snd_pcm_sframes_t bufsize;
int fragments;
bufsize = ALSA_snd_pcm_hw_params_get_period_size(hwparams);
fragments = ALSA_snd_pcm_hw_params_get_periods(hwparams);
fprintf(stderr, "ALSA: bufsize = %ld, fragments = %d\n", bufsize,
fragments);
}
#endif
/* Set the software parameters */
snd_pcm_sw_params_alloca(&swparams);
status = ALSA_snd_pcm_sw_params_current(pcm_handle, swparams);
if (status < 0) {
ALSA_CloseDevice(this);
SDL_SetError("ALSA: Couldn't get software config: %s",
ALSA_snd_strerror(status));
return 0;
}
status =
ALSA_snd_pcm_sw_params_set_start_threshold(pcm_handle, swparams, 0);
if (status < 0) {
ALSA_CloseDevice(this);
SDL_SetError("ALSA: Couldn't set start threshold: %s",
ALSA_snd_strerror(status));
return 0;
}
status =
ALSA_snd_pcm_sw_params_set_avail_min(pcm_handle, swparams, frames);
if (status < 0) {
ALSA_CloseDevice(this);
SDL_SetError("Couldn't set avail min: %s", ALSA_snd_strerror(status));
return 0;
}
status = ALSA_snd_pcm_sw_params(pcm_handle, swparams);
if (status < 0) {
ALSA_CloseDevice(this);
SDL_SetError("Couldn't set software audio parameters: %s",
ALSA_snd_strerror(status));
return 0;
}
/* Calculate the final parameters for this audio specification */
SDL_CalculateAudioSpec(&this->spec);
/* Allocate mixing buffer */
this->hidden->mixlen = this->spec.size;
this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(this->hidden->mixlen);
if (this->hidden->mixbuf == NULL) {
ALSA_CloseDevice(this);
SDL_OutOfMemory();
return 0;
}
SDL_memset(this->hidden->mixbuf, this->spec.silence, this->spec.size);
/* Get the parent process id (we're the parent of the audio thread) */
this->hidden->parent = getpid();
/* Switch to blocking mode for playback */
ALSA_snd_pcm_nonblock(pcm_handle, 0);
/* We're ready to rock and roll. :-) */
return 1;
}
