Genesis-Plus-GX/gx/gx_audio.c
2013-06-17 22:42:05 +02:00

228 lines
6.8 KiB
C

/****************************************************************************
* gx_audio.c
*
* Genesis Plus GX audio support
*
* Copyright Eke-Eke (2007-2013), based on original work from Softdev (2006)
*
* Redistribution and use of this code or any derivative works are permitted
* provided that the following conditions are met:
*
* - Redistributions may not be sold, nor may they be used in a commercial
* product or activity.
*
* - Redistributions that are modified from the original source must include the
* complete source code, including the source code for all components used by a
* binary built from the modified sources. However, as a special exception, the
* source code distributed need not include anything that is normally distributed
* (in either source or binary form) with the major components (compiler, kernel,
* and so on) of the operating system on which the executable runs, unless that
* component itself accompanies the executable.
*
* - Redistributions must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************************/
#include "shared.h"
/* Length is dimensionned for at least one frame of emulation */
#define SOUND_BUFFER_LEN 4096
/* Number of sound buffers */
#define SOUND_BUFFER_NUM 3
/* audio DMA status */
u32 audioStarted;
/* DMA soundbuffers (required to be 32-bytes aligned) */
static u8 soundbuffer[SOUND_BUFFER_NUM][SOUND_BUFFER_LEN] ATTRIBUTE_ALIGN(32);
/* Current work soundbuffer */
static u8 mixbuffer;
/* Background music */
static u8 *Bg_music_ogg = NULL;
static u32 Bg_music_ogg_size = 0;
/* Frame Sync */
static u8 audio_sync;
/***************************************************************************************/
/* Audio engine */
/***************************************************************************************/
/* Audio DMA callback */
static void ai_callback(void)
{
#ifdef LOG_TIMING
u64 current = gettime();
if (prevtime)
{
delta_time[frame_cnt] = diff_nsec(prevtime, current);
frame_cnt = (frame_cnt + 1) % LOGSIZE;
}
prevtime = current;
#endif
audio_sync = 0;
}
/* AUDIO engine initialization */
void gx_audio_Init(void)
{
/* Initialize AUDIO processing library (ASNDLIB) */
/* AUDIO & DSP hardware are initialized */
/* Default samplerate is set to 48kHz */
ASND_Init();
/* Load background music from FAT device */
char fname[MAXPATHLEN];
sprintf(fname,"%s/Bg_music.ogg",DEFAULT_PATH);
FILE *f = fopen(fname,"rb");
if (f)
{
struct stat filestat;
stat(fname, &filestat);
Bg_music_ogg_size = filestat.st_size;
Bg_music_ogg = memalign(32,Bg_music_ogg_size);
if (Bg_music_ogg)
{
fread(Bg_music_ogg,1,Bg_music_ogg_size,f);
}
fclose(f);
}
}
/* AUDIO engine shutdown */
void gx_audio_Shutdown(void)
{
PauseOgg(1);
StopOgg();
ASND_Pause(1);
ASND_End();
if (Bg_music_ogg)
{
free(Bg_music_ogg);
}
}
/***
gx_audio_Update
This function retrieves samples for the frame then set the next DMA parameters
Parameters will be taken in account only when current DMA operation is over
***/
int gx_audio_Update(void)
{
if (!audio_sync)
{
/* Current available soundbuffer */
s16 *sb = (s16 *)(soundbuffer[mixbuffer]);
/* Retrieve audio samples (size must be multiple of 32 bytes) */
int size = audio_update(sb) * 4;
#ifdef LOG_TIMING
if (prevtime && (frame_cnt < LOGSIZE - 1))
{
delta_samp[frame_cnt + 1] = size;
}
else
{
delta_samp[0] = size;
}
#endif
/* Update DMA settings */
DCFlushRange((void *)sb, size);
AUDIO_InitDMA((u32) sb, size);
mixbuffer = (mixbuffer + 1) % SOUND_BUFFER_NUM;
audio_sync = 1;
/* Start Audio DMA */
/* this is called once to kick-off DMA from external memory to audio interface */
/* DMA operation is automatically restarted when all samples have been sent. */
/* If DMA settings are not updated at that time, previous sound buffer will be used. */
/* Therefore we need to make sure frame emulation is completed before current DMA is */
/* completed, by synchronizing frame emulation with DMA start and also by syncing it */
/* with Video Interrupt and outputing a suitable number of samples per frame. */
if (!audioStarted)
{
/* restart audio DMA */
AUDIO_StopDMA();
AUDIO_StartDMA();
audioStarted = 1;
}
return SYNC_AUDIO;
}
return NO_SYNC;
}
/***
gx_audio_Start
This function restart the audio engine
This is called when coming back from Main Menu
***/
void gx_audio_Start(void)
{
/* shutdown background music */
PauseOgg(1);
StopOgg();
/* shutdown menu audio processing */
ASND_Pause(1);
ASND_End();
AUDIO_StopDMA();
AUDIO_RegisterDMACallback(NULL);
DSP_Halt();
/* DMA Interrupt callback */
AUDIO_RegisterDMACallback(ai_callback);
/* reset emulation audio processing */
memset(soundbuffer, 0, 3 * SOUND_BUFFER_LEN);
audioStarted = 0;
mixbuffer = 0;
audio_sync = 0;
}
/***
gx_audio_Stop
This function stops current Audio DMA process
This is called when going back to Main Menu
DMA need to be restarted when going back to the game (see above)
***/
void gx_audio_Stop(void)
{
/* restart menu audio processing */
DSP_Unhalt();
ASND_Init();
ASND_Pause(0);
/* play background music */
if (Bg_music_ogg && !Shutdown)
{
PauseOgg(0);
PlayOgg((char *)Bg_music_ogg, Bg_music_ogg_size, 0, OGG_INFINITE_TIME);
SetVolumeOgg(((int)config.bgm_volume * 255) / 100);
}
}