godot/drivers/alsa/audio_driver_alsa.cpp
2017-09-01 11:12:13 -03:00

263 lines
7.5 KiB
C++

/*************************************************************************/
/* audio_driver_alsa.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2017 Godot Engine contributors (cf. AUTHORS.md) */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/*************************************************************************/
#include "audio_driver_alsa.h"
#ifdef ALSA_ENABLED
#include "os/os.h"
#include "project_settings.h"
#include <errno.h>
Error AudioDriverALSA::init() {
active = false;
thread_exited = false;
exit_thread = false;
pcm_open = false;
samples_in = NULL;
samples_out = NULL;
mix_rate = GLOBAL_DEF("audio/mix_rate", DEFAULT_MIX_RATE);
speaker_mode = SPEAKER_MODE_STEREO;
channels = 2;
int status;
snd_pcm_hw_params_t *hwparams;
snd_pcm_sw_params_t *swparams;
#define CHECK_FAIL(m_cond) \
if (m_cond) { \
fprintf(stderr, "ALSA ERR: %s\n", snd_strerror(status)); \
snd_pcm_close(pcm_handle); \
ERR_FAIL_COND_V(m_cond, ERR_CANT_OPEN); \
}
//todo, add
//6 chans - "plug:surround51"
//4 chans - "plug:surround40";
status = snd_pcm_open(&pcm_handle, "default", SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
ERR_FAIL_COND_V(status < 0, ERR_CANT_OPEN);
snd_pcm_hw_params_alloca(&hwparams);
status = snd_pcm_hw_params_any(pcm_handle, hwparams);
CHECK_FAIL(status < 0);
status = snd_pcm_hw_params_set_access(pcm_handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED);
CHECK_FAIL(status < 0);
//not interested in anything else
status = snd_pcm_hw_params_set_format(pcm_handle, hwparams, SND_PCM_FORMAT_S16_LE);
CHECK_FAIL(status < 0);
//todo: support 4 and 6
status = snd_pcm_hw_params_set_channels(pcm_handle, hwparams, 2);
CHECK_FAIL(status < 0);
status = snd_pcm_hw_params_set_rate_near(pcm_handle, hwparams, &mix_rate, NULL);
CHECK_FAIL(status < 0);
// In ALSA the period size seems to be the one that will determine the actual latency
// Ref: https://www.alsa-project.org/main/index.php/FramesPeriods
unsigned int periods = 2;
int latency = GLOBAL_DEF("audio/output_latency", DEFAULT_OUTPUT_LATENCY);
buffer_frames = closest_power_of_2(latency * mix_rate / 1000);
buffer_size = buffer_frames * periods;
period_size = buffer_frames;
// set buffer size from project settings
status = snd_pcm_hw_params_set_buffer_size_near(pcm_handle, hwparams, &buffer_size);
CHECK_FAIL(status < 0);
status = snd_pcm_hw_params_set_period_size_near(pcm_handle, hwparams, &period_size, NULL);
CHECK_FAIL(status < 0);
if (OS::get_singleton()->is_stdout_verbose()) {
print_line("audio buffer frames: " + itos(period_size) + " calculated latency: " + itos(period_size * 1000 / mix_rate) + "ms");
}
status = snd_pcm_hw_params_set_periods_near(pcm_handle, hwparams, &periods, NULL);
CHECK_FAIL(status < 0);
status = snd_pcm_hw_params(pcm_handle, hwparams);
CHECK_FAIL(status < 0);
//snd_pcm_hw_params_free(&hwparams);
snd_pcm_sw_params_alloca(&swparams);
status = snd_pcm_sw_params_current(pcm_handle, swparams);
CHECK_FAIL(status < 0);
status = snd_pcm_sw_params_set_avail_min(pcm_handle, swparams, period_size);
CHECK_FAIL(status < 0);
status = snd_pcm_sw_params_set_start_threshold(pcm_handle, swparams, 1);
CHECK_FAIL(status < 0);
status = snd_pcm_sw_params(pcm_handle, swparams);
CHECK_FAIL(status < 0);
samples_in = memnew_arr(int32_t, period_size * channels);
samples_out = memnew_arr(int16_t, period_size * channels);
snd_pcm_nonblock(pcm_handle, 0);
mutex = Mutex::create();
thread = Thread::create(AudioDriverALSA::thread_func, this);
return OK;
};
void AudioDriverALSA::thread_func(void *p_udata) {
AudioDriverALSA *ad = (AudioDriverALSA *)p_udata;
while (!ad->exit_thread) {
if (!ad->active) {
for (unsigned int i = 0; i < ad->period_size * ad->channels; i++) {
ad->samples_out[i] = 0;
};
} else {
ad->lock();
ad->audio_server_process(ad->period_size, ad->samples_in);
ad->unlock();
for (unsigned int i = 0; i < ad->period_size * ad->channels; i++) {
ad->samples_out[i] = ad->samples_in[i] >> 16;
}
};
int todo = ad->period_size;
int total = 0;
while (todo) {
if (ad->exit_thread)
break;
uint8_t *src = (uint8_t *)ad->samples_out;
int wrote = snd_pcm_writei(ad->pcm_handle, (void *)(src + (total * ad->channels)), todo);
if (wrote < 0) {
if (ad->exit_thread)
break;
if (wrote == -EAGAIN) {
//can't write yet (though this is blocking..)
usleep(1000);
continue;
}
wrote = snd_pcm_recover(ad->pcm_handle, wrote, 0);
if (wrote < 0) {
//absolute fail
fprintf(stderr, "ALSA failed and can't recover: %s\n", snd_strerror(wrote));
ad->active = false;
ad->exit_thread = true;
break;
}
continue;
};
total += wrote;
todo -= wrote;
};
};
ad->thread_exited = true;
};
void AudioDriverALSA::start() {
active = true;
};
int AudioDriverALSA::get_mix_rate() const {
return mix_rate;
};
AudioDriver::SpeakerMode AudioDriverALSA::get_speaker_mode() const {
return speaker_mode;
};
void AudioDriverALSA::lock() {
if (!thread || !mutex)
return;
mutex->lock();
};
void AudioDriverALSA::unlock() {
if (!thread || !mutex)
return;
mutex->unlock();
};
void AudioDriverALSA::finish() {
if (!thread)
return;
exit_thread = true;
Thread::wait_to_finish(thread);
if (pcm_open)
snd_pcm_close(pcm_handle);
if (samples_in) {
memdelete_arr(samples_in);
memdelete_arr(samples_out);
};
memdelete(thread);
if (mutex)
memdelete(mutex);
thread = NULL;
};
AudioDriverALSA::AudioDriverALSA() {
mutex = NULL;
thread = NULL;
pcm_handle = NULL;
};
AudioDriverALSA::~AudioDriverALSA(){
};
#endif