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/* sdlsound.c: SDL sound I/O
Copyright (c) 2002-2004 Alexander Yurchenko, Russell Marks, Philip Kendall,
Fredrick Meunier
$Id: sdlsound.c 4031 2009-06-08 00:33:53Z fredm $
This program 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 Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <config.h>
#include <errno.h>
#include <fcntl.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <SDL.h>
#include "settings.h"
#include "sfifo.h"
#include "sound.h"
#include "ui/ui.h"
static void sdlwrite( void *userdata, Uint8 *stream, int len );
sfifo_t sound_fifo;
/* Number of Spectrum frames audio latency to use */
#define NUM_FRAMES 2
/* Records sound writer status information */
static int audio_output_started;
int
sound_lowlevel_init( const char *device, int *freqptr, int *stereoptr )
{
SDL_AudioSpec requested, received;
int error;
float hz;
int sound_framesiz;
#ifndef __MORPHOS__
/* I'd rather just use setenv, but Windows doesn't have it */
if( device ) {
const char *environment = "SDL_AUDIODRIVER=";
char *command = malloc( strlen( environment ) + strlen( device ) + 1 );
strcpy( command, environment );
strcat( command, device );
error = putenv( command );
free( command );
if( error ) {
settings_current.sound = 0;
ui_error( UI_ERROR_ERROR, "Couldn't set SDL_AUDIODRIVER: %s",
strerror ( error ) );
return 1;
}
}
#endif /* #ifndef __MORPHOS__ */
SDL_InitSubSystem( SDL_INIT_AUDIO );
memset( &requested, 0, sizeof( SDL_AudioSpec ) );
requested.freq = *freqptr;
requested.channels = *stereoptr ? 2 : 1;
requested.format = AUDIO_S16SYS;
requested.callback = sdlwrite;
/* Adjust relative processor speed to deal with adjusting sound generation
frequency against emulation speed (more flexible than adjusting generated
sample rate) */
hz = (float)sound_get_effective_processor_speed() /
machine_current->timings.tstates_per_frame;
/* Amount of audio data we will accumulate before yielding back to the OS.
Not much point having more than 100Hz playback, we probably get
downgraded by the OS as being a hog too (unlimited Hz limits playback
speed to about 2000% on my Mac, 100Hz allows up to 5000% for me) */
if( hz > 100.0 ) hz = 100.0;
sound_framesiz = *freqptr / hz;
requested.samples = sound_framesiz;
if ( SDL_OpenAudio( &requested, &received ) < 0 ) {
settings_current.sound = 0;
ui_error( UI_ERROR_ERROR, "Couldn't open sound device: %s",
SDL_GetError() );
return 1;
}
*freqptr = received.freq;
if( received.format != AUDIO_S16SYS ) {
/* close audio and then just let SDL convert to this wacky format at a
supported sample rate */
SDL_CloseAudio();
requested.freq = *freqptr;
sound_framesiz = *freqptr / hz;
requested.samples = sound_framesiz;
if( SDL_OpenAudio( &requested, NULL ) < 0 ) {
settings_current.sound = 0;
ui_error( UI_ERROR_ERROR, "Couldn't open sound device: %s",
SDL_GetError() );
return 1;
}
} else {
*stereoptr = received.channels == 1 ? 0 : 1;
}
sound_framesiz = *freqptr / hz;
sound_framesiz <<= 1;
if( ( error = sfifo_init( &sound_fifo, NUM_FRAMES
* received.channels
* sound_framesiz + 1 ) ) ) {
ui_error( UI_ERROR_ERROR, "Problem initialising sound fifo: %s",
strerror ( error ) );
return 1;
}
/* wait to run sound until we have some sound to play */
audio_output_started = 0;
return 0;
}
void
sound_lowlevel_end( void )
{
SDL_PauseAudio( 1 );
SDL_LockAudio();
SDL_CloseAudio();
SDL_QuitSubSystem( SDL_INIT_AUDIO );
sfifo_flush( &sound_fifo );
sfifo_close( &sound_fifo );
}
/* Copy data to fifo */
void
sound_lowlevel_frame( libspectrum_signed_word *data, int len )
{
int i = 0;
/* Convert to bytes */
libspectrum_signed_byte* bytes = (libspectrum_signed_byte*)data;
len <<= 1;
while( len ) {
if( ( i = sfifo_write( &sound_fifo, bytes, len ) ) < 0 ) {
break;
} else if (!i) {
SDL_Delay(10);
}
bytes += i;
len -= i;
}
if( i < 0 ) {
ui_error( UI_ERROR_ERROR, "Couldn't write sound fifo: %s",
strerror( i ) );
}
if( !audio_output_started ) {
SDL_PauseAudio( 0 );
audio_output_started = 1;
}
}
#ifndef MIN
#define MIN(a,b) (((a) < (b)) ? (a) : (b))
#endif
/* Write len samples from fifo into stream */
void
sdlwrite( void *userdata, Uint8 *stream, int len )
{
int f;
/* Try to only read an even number of bytes so as not to fragment a sample */
len = MIN( len, sfifo_used( &sound_fifo ) );
len &= sound_stereo ? 0xfffc : 0xfffe;
/* Read input_size bytes from fifo into sound stream */
while( ( f = sfifo_read( &sound_fifo, stream, len ) ) > 0 ) {
stream += f;
len -= f;
}
/* If we ran out of sound, do nothing else as SDL has prefilled
the output buffer with silence :( */
}
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