RetroArch/audio/openal.c

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C
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/* SSNES - A Super Ninteno Entertainment System (SNES) Emulator frontend for libsnes.
* Copyright (C) 2010 - Hans-Kristian Arntzen
*
* Some code herein may be based on code found in BSNES.
*
* SSNES 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.
*
* SSNES 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 SSNES.
* If not, see <http://www.gnu.org/licenses/>.
*/
#include "driver.h"
#include <AL/al.h>
#include <AL/alc.h>
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#include <time.h>
#include <string.h>
#ifdef _WIN32
#include <windows.h>
#endif
#define BUFSIZE 128
typedef struct al
{
ALuint source;
ALuint *buffers;
ALuint *res_buf;
int res_ptr;
ALenum format;
int num_buffers;
int rate;
int queue;
uint8_t tmpbuf[BUFSIZE];
int tmpbuf_ptr;
ALCdevice *handle;
ALCcontext *ctx;
bool nonblock;
} al_t;
static void* __al_init(const char* device, int rate, int latency)
{
(void)device;
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al_t *al = calloc(1, sizeof(al_t));
if ( al == NULL )
return NULL;
al->handle = alcOpenDevice(NULL);
if (al->handle == NULL)
goto error;
al->ctx = alcCreateContext(al->handle, NULL);
if (al->ctx == NULL)
goto error;
alcMakeContextCurrent(al->ctx);
al->rate = rate;
al->num_buffers = (latency * rate * 2 * 2) / (1000 * BUFSIZE);
al->buffers = calloc(al->num_buffers, sizeof(ALuint));
al->res_buf = calloc(al->num_buffers, sizeof(ALuint));
if (al->buffers == NULL || al->res_buf == NULL)
goto error;
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alGenSources(1, &al->source);
alGenBuffers(al->num_buffers, al->buffers);
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memcpy(al->res_buf, al->buffers, al->num_buffers * sizeof(ALuint));
al->res_ptr = al->num_buffers;
return al;
error:
if (al)
{
alcMakeContextCurrent(NULL);
if (al->ctx)
alcDestroyContext(al->ctx);
if (al->handle)
alcCloseDevice(al->handle);
if (al->buffers)
free(al->buffers);
if (al->res_buf)
free(al->res_buf);
free(al);
}
return NULL;
}
static bool al_unqueue_buffers(al_t *al)
{
ALint val;
alGetSourcei(al->source, AL_BUFFERS_PROCESSED, &val);
if (val > 0)
{
alSourceUnqueueBuffers(al->source, val, &al->res_buf[al->res_ptr]);
al->res_ptr += val;
return true;
}
return false;
}
static bool al_get_buffer(al_t *al, ALuint *buffer)
{
if (al->res_ptr == 0)
{
#ifndef _WIN32
struct timespec tv = {
.tv_sec = 0,
.tv_nsec = 1000000
};
#endif
for(;;)
{
if (al_unqueue_buffers(al))
break;
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if (al->nonblock)
return false;
#ifdef _WIN32
Sleep(1);
#else
nanosleep(&tv, NULL);
#endif
}
}
*buffer = al->res_buf[--al->res_ptr];
return true;
}
static size_t al_fill_internal_buf(al_t *al, const void* buf, size_t size)
{
size_t read_size = (BUFSIZE - al->tmpbuf_ptr > size) ? size : (BUFSIZE - al->tmpbuf_ptr);
memcpy(al->tmpbuf + al->tmpbuf_ptr, buf, read_size);
al->tmpbuf_ptr += read_size;
return read_size;
}
static ssize_t __al_write(void* data, const void* buf, size_t size)
{
al_t *al = data;
size_t written = 0;
while (written < size)
{
size_t rc = al_fill_internal_buf(al, (const char*)buf + written, size - written);
written += rc;
if (al->tmpbuf_ptr != BUFSIZE)
break;
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ALuint buffer;
if (!al_get_buffer(al, &buffer))
return 0;
alBufferData(buffer, AL_FORMAT_STEREO16, al->tmpbuf, BUFSIZE, al->rate);
al->tmpbuf_ptr = 0;
alSourceQueueBuffers(al->source, 1, &buffer);
if (alGetError() != AL_NO_ERROR)
return -1;
ALint val;
alGetSourcei(al->source, AL_SOURCE_STATE, &val);
if (val != AL_PLAYING)
alSourcePlay(al->source);
if (alGetError() != AL_NO_ERROR)
return -1;
}
return size;
}
static bool __al_stop(void *data)
{
(void)data;
return true;
}
static void __al_set_nonblock_state(void *data, bool state)
{
al_t *al = data;
al->nonblock = state;
}
static bool __al_start(void *data)
{
(void)data;
return true;
}
static void __al_free(void *data)
{
al_t *al= data;
if (al)
{
alSourceStop(al->source);
alDeleteSources(1, &al->source);
if ( al->buffers )
{
alDeleteBuffers(al->num_buffers, al->buffers);
free(al->buffers);
free(al->res_buf);
}
}
alcMakeContextCurrent(NULL);
alcDestroyContext(al->ctx);
alcCloseDevice(al->handle);
free(al);
}
const audio_driver_t audio_openal = {
.init = __al_init,
.write = __al_write,
.stop = __al_stop,
.start = __al_start,
.set_nonblock_state = __al_set_nonblock_state,
.free = __al_free,
.ident = "openal"
};