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RetroArch/audio/drivers/sdl_audio.c

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/* RetroArch - A frontend for libretro.
* Copyright (C) 2010-2014 - Hans-Kristian Arntzen
* Copyright (C) 2011-2017 - Daniel De Matteis
*
* RetroArch is free software: you can redistribute it and/or modify it under the terms
* of the GNU General Public License as published by the Free Software Found-
* ation, either version 3 of the License, or (at your option) any later version.
*
* RetroArch is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with RetroArch.
* If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdint.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <boolean.h>
#include <rthreads/rthreads.h>
#include <queues/fifo_queue.h>
#include <retro_inline.h>
#include <retro_math.h>
#include "SDL.h"
#include "SDL_audio.h"
#include "../audio_driver.h"
#include "../../verbosity.h"
#include "retro_assert.h"
#ifndef HAVE_SDL2
typedef Uint32 SDL_AudioDeviceID;
/** Compatibility stub that defers to SDL_PauseAudio. */
#define SDL_PauseAudioDevice(dev, pause_on) SDL_PauseAudio(pause_on)
/** Compatibility stub that defers to SDL_LockAudio. */
#define SDL_LockAudioDevice(dev) SDL_LockAudio()
/** Compatibility stub that defers to SDL_UnlockAudio. */
#define SDL_UnlockAudioDevice(dev) SDL_UnlockAudio()
/** Compatibility stub that defers to SDL_CloseAudio. */
#define SDL_CloseAudioDevice(dev) SDL_CloseAudio()
/* Macros for checking audio format bits that were introduced in SDL 2 */
#define SDL_AUDIO_MASK_BITSIZE (0xFF)
#define SDL_AUDIO_MASK_DATATYPE (1<<8)
#define SDL_AUDIO_MASK_ENDIAN (1<<12)
#define SDL_AUDIO_MASK_SIGNED (1<<15)
#define SDL_AUDIO_BITSIZE(x) (x & SDL_AUDIO_MASK_BITSIZE)
#define SDL_AUDIO_ISFLOAT(x) (x & SDL_AUDIO_MASK_DATATYPE)
#define SDL_AUDIO_ISBIGENDIAN(x) (x & SDL_AUDIO_MASK_ENDIAN)
#define SDL_AUDIO_ISSIGNED(x) (x & SDL_AUDIO_MASK_SIGNED)
#define SDL_AUDIO_ISINT(x) (!SDL_AUDIO_ISFLOAT(x))
#define SDL_AUDIO_ISLITTLEENDIAN(x) (!SDL_AUDIO_ISBIGENDIAN(x))
#define SDL_AUDIO_ISUNSIGNED(x) (!SDL_AUDIO_ISSIGNED(x))
#endif
typedef struct sdl_audio
{
#ifdef HAVE_THREADS
slock_t *lock;
scond_t *cond;
#endif
/**
* The queue used to store outgoing samples to be played by the driver.
* Audio from the core ultimately makes its way here,
* the last stop before the driver plays it.
*/
fifo_buffer_t *speaker_buffer;
bool nonblock;
bool is_paused;
SDL_AudioDeviceID speaker_device;
} sdl_audio_t;
static void sdl_audio_playback_cb(void *data, Uint8 *stream, int len)
{
sdl_audio_t *sdl = (sdl_audio_t*)data;
size_t avail = FIFO_READ_AVAIL(sdl->speaker_buffer);
size_t write_size = len > (int)avail ? avail : len;
fifo_read(sdl->speaker_buffer, stream, write_size);
#ifdef HAVE_THREADS
scond_signal(sdl->cond);
#endif
/* If underrun, fill rest with silence. */
memset(stream + write_size, 0, len - write_size);
}
static INLINE int find_num_frames(int rate, int latency)
{
int frames = (rate * latency) / 1000;
/* SDL only likes 2^n sized buffers. */
return next_pow2(frames);
}
static void *sdl_audio_init(const char *device,
unsigned rate, unsigned latency,
unsigned block_frames,
unsigned *new_rate)
{
int frames;
size_t bufsize;
SDL_AudioSpec out;
SDL_AudioSpec spec = {0};
void *tmp = NULL;
sdl_audio_t *sdl = NULL;
uint32_t sdl_subsystem_flags = SDL_WasInit(0);
(void)device;
/* Initialise audio subsystem, if required */
if (sdl_subsystem_flags == 0)
{
if (SDL_Init(SDL_INIT_AUDIO) < 0)
return NULL;
}
else if ((sdl_subsystem_flags & SDL_INIT_AUDIO) == 0)
{
if (SDL_InitSubSystem(SDL_INIT_AUDIO) < 0)
return NULL;
}
sdl = (sdl_audio_t*)calloc(1, sizeof(*sdl));
if (!sdl)
return NULL;
/* We have to buffer up some data ourselves, so we let SDL
* carry approximately half of the latency.
*
* SDL double buffers audio and we do as well. */
frames = find_num_frames(rate, latency / 4);
/* First, let's initialize the output device. */
spec.freq = rate;
spec.format = AUDIO_S16SYS;
spec.channels = 2;
spec.samples = frames; /* This is in audio frames, not samples ... :( */
spec.callback = sdl_audio_playback_cb;
spec.userdata = sdl;
/* No compatibility stub for SDL_OpenAudioDevice because its return value
* is different from that of SDL_OpenAudio. */
#ifdef HAVE_SDL2
sdl->speaker_device = SDL_OpenAudioDevice(NULL, false, &spec, &out, 0);
if (sdl->speaker_device == 0)
#else
sdl->speaker_device = SDL_OpenAudio(&spec, &out);
if (sdl->speaker_device < 0)
#endif
{
RARCH_ERR("[SDL audio]: Failed to open SDL audio output device: %s\n", SDL_GetError());
goto error;
}
*new_rate = out.freq;
RARCH_DBG("[SDL audio]: Opened SDL audio out device with ID %u\n",
sdl->speaker_device);
RARCH_DBG("[SDL audio]: Requested a speaker frequency of %u Hz, got %u Hz\n",
spec.freq, out.freq);
RARCH_DBG("[SDL audio]: Requested %u channels for speaker, got %u\n",
spec.channels, out.channels);
RARCH_DBG("[SDL audio]: Requested a %u-frame speaker buffer, got %u frames (%u bytes)\n",
frames, out.samples, out.size);
RARCH_DBG("[SDL audio]: Got a speaker silence value of %u\n", out.silence);
RARCH_DBG("[SDL audio]: Requested speaker audio format: %u-bit %s %s %s endian\n",
SDL_AUDIO_BITSIZE(spec.format),
SDL_AUDIO_ISSIGNED(spec.format) ? "signed" : "unsigned",
SDL_AUDIO_ISFLOAT(spec.format) ? "floating-point" : "integer",
SDL_AUDIO_ISBIGENDIAN(spec.format) ? "big" : "little");
RARCH_DBG("[SDL audio]: Received speaker audio format: %u-bit %s %s %s endian\n",
SDL_AUDIO_BITSIZE(spec.format),
SDL_AUDIO_ISSIGNED(spec.format) ? "signed" : "unsigned",
SDL_AUDIO_ISFLOAT(spec.format) ? "floating-point" : "integer",
SDL_AUDIO_ISBIGENDIAN(spec.format) ? "big" : "little");
#ifdef HAVE_THREADS
sdl->lock = slock_new();
sdl->cond = scond_new();
#endif
RARCH_LOG("[SDL audio]: Requested %u ms latency for output device, got %d ms\n",
latency, (int)(out.samples * 4 * 1000 / (*new_rate)));
/* Create a buffer twice as big as needed and prefill the buffer. */
bufsize = out.samples * 4 * sizeof(int16_t);
tmp = calloc(1, bufsize);
sdl->speaker_buffer = fifo_new(bufsize);
if (tmp)
{
fifo_write(sdl->speaker_buffer, tmp, bufsize);
free(tmp);
}
RARCH_DBG("[SDL audio]: Initialized speaker sample queue with %u bytes\n", bufsize);
SDL_PauseAudioDevice(sdl->speaker_device, false);
return sdl;
error:
free(sdl);
return NULL;
}
static ssize_t sdl_audio_write(void *data, const void *buf, size_t size)
{
ssize_t ret = 0;
sdl_audio_t *sdl = (sdl_audio_t*)data;
if (sdl->nonblock)
{ /* If we shouldn't wait for space in a full outgoing sample queue... */
size_t avail, write_amt;
SDL_LockAudioDevice(sdl->speaker_device); /* Stop the SDL speaker thread from running */
avail = FIFO_WRITE_AVAIL(sdl->speaker_buffer);
write_amt = avail > size ? size : avail; /* Enqueue as much data as we can */
fifo_write(sdl->speaker_buffer, buf, write_amt);
SDL_UnlockAudioDevice(sdl->speaker_device); /* Let the speaker thread run again */
ret = write_amt; /* If the queue was full...well, too bad. */
}
else
{
size_t written = 0;
while (written < size)
{ /* Until we've written all the sample data we have available... */
size_t avail;
SDL_LockAudioDevice(sdl->speaker_device); /* Stop the SDL speaker thread from running */
avail = FIFO_WRITE_AVAIL(sdl->speaker_buffer);
if (avail == 0)
{ /* If the outgoing sample queue is full... */
SDL_UnlockAudioDevice(sdl->speaker_device);
/* Let the SDL speaker thread run so it can play the enqueued samples,
* which will free up space for us to write new ones. */
#ifdef HAVE_THREADS
slock_lock(sdl->lock);
/* Let *only* the SDL speaker thread touch the outgoing sample queue */
scond_wait(sdl->cond, sdl->lock);
/* Block until SDL tells us that it's made room for new samples */
slock_unlock(sdl->lock);
/* Now let this thread use the outgoing sample queue (which we'll do next iteration) */
#endif
}
else
{
size_t write_amt = size - written > avail ? avail : size - written;
fifo_write(sdl->speaker_buffer, (const char*)buf + written, write_amt);
/* Enqueue as many samples as we have available without overflowing the queue */
SDL_UnlockAudioDevice(sdl->speaker_device); /* Let the SDL speaker thread run again */
written += write_amt;
}
}
ret = written;
}
return ret;
}
static bool sdl_audio_stop(void *data)
{
sdl_audio_t *sdl = (sdl_audio_t*)data;
sdl->is_paused = true;
SDL_PauseAudioDevice(sdl->speaker_device, true);
return true;
}
static bool sdl_audio_alive(void *data)
{
sdl_audio_t *sdl = (sdl_audio_t*)data;
if (!sdl)
return false;
return !sdl->is_paused;
}
static bool sdl_audio_start(void *data, bool is_shutdown)
{
sdl_audio_t *sdl = (sdl_audio_t*)data;
sdl->is_paused = false;
SDL_PauseAudioDevice(sdl->speaker_device, false);
return true;
}
static void sdl_audio_set_nonblock_state(void *data, bool state)
{
sdl_audio_t *sdl = (sdl_audio_t*)data;
if (sdl)
sdl->nonblock = state;
}
static void sdl_audio_free(void *data)
{
sdl_audio_t *sdl = (sdl_audio_t*)data;
if (sdl)
{
if (sdl->speaker_device > 0)
{
SDL_CloseAudioDevice(sdl->speaker_device);
}
if (sdl->speaker_buffer)
{
fifo_free(sdl->speaker_buffer);
}
#ifdef HAVE_THREADS
slock_free(sdl->lock);
scond_free(sdl->cond);
#endif
SDL_QuitSubSystem(SDL_INIT_AUDIO);
}
free(sdl);
}
static bool sdl_audio_use_float(void *data)
{
(void)data;
return false;
}
static size_t sdl_audio_write_avail(void *data)
{
/* stub */
(void)data;
return 0;
}
audio_driver_t audio_sdl = {
sdl_audio_init,
sdl_audio_write,
sdl_audio_stop,
sdl_audio_start,
sdl_audio_alive,
sdl_audio_set_nonblock_state,
sdl_audio_free,
sdl_audio_use_float,
#ifdef HAVE_SDL2
"sdl2",
#else
"sdl",
#endif
NULL,
NULL,
sdl_audio_write_avail,
NULL
};
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