mirror of
https://github.com/ekeeke/Genesis-Plus-GX.git
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228 lines
6.8 KiB
C
228 lines
6.8 KiB
C
/****************************************************************************
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* gx_audio.c
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*
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* Genesis Plus GX audio support
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*
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* Copyright Eke-Eke (2007-2012), based on original work from Softdev (2006)
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*
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* Redistribution and use of this code or any derivative works are permitted
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* provided that the following conditions are met:
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*
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* - Redistributions may not be sold, nor may they be used in a commercial
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* product or activity.
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*
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* - Redistributions that are modified from the original source must include the
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* complete source code, including the source code for all components used by a
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* binary built from the modified sources. However, as a special exception, the
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* source code distributed need not include anything that is normally distributed
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* (in either source or binary form) with the major components (compiler, kernel,
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* and so on) of the operating system on which the executable runs, unless that
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* component itself accompanies the executable.
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*
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* - Redistributions must reproduce the above copyright notice, this list of
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* conditions and the following disclaimer in the documentation and/or other
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* materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************************/
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#include "shared.h"
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/* Length is dimensionned for at least one frame of emulation */
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#define SOUND_BUFFER_LEN 4096
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/* Number of sound buffers */
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#define SOUND_BUFFER_NUM 3
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/* audio DMA status */
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u32 audioStarted;
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/* DMA soundbuffers (required to be 32-bytes aligned) */
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static u8 soundbuffer[SOUND_BUFFER_NUM][SOUND_BUFFER_LEN] ATTRIBUTE_ALIGN(32);
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/* Current work soundbuffer */
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static u8 mixbuffer;
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/* Background music */
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static u8 *Bg_music_ogg = NULL;
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static u32 Bg_music_ogg_size = 0;
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/* Frame Sync */
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static u8 audio_sync;
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/***************************************************************************************/
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/* Audio engine */
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/***************************************************************************************/
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/* Audio DMA callback */
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static void ai_callback(void)
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{
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#ifdef LOG_TIMING
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u64 current = gettime();
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if (prevtime)
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{
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delta_time[frame_cnt] = diff_nsec(prevtime, current);
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frame_cnt = (frame_cnt + 1) % LOGSIZE;
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}
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prevtime = current;
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#endif
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audio_sync = 0;
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}
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/* AUDIO engine initialization */
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void gx_audio_Init(void)
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{
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/* Initialize AUDIO processing library (ASNDLIB) */
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/* AUDIO & DSP hardware are initialized */
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/* Default samplerate is set to 48kHz */
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ASND_Init();
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/* Load background music from FAT device */
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char fname[MAXPATHLEN];
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sprintf(fname,"%s/Bg_music.ogg",DEFAULT_PATH);
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FILE *f = fopen(fname,"rb");
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if (f)
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{
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struct stat filestat;
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stat(fname, &filestat);
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Bg_music_ogg_size = filestat.st_size;
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Bg_music_ogg = memalign(32,Bg_music_ogg_size);
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if (Bg_music_ogg)
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{
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fread(Bg_music_ogg,1,Bg_music_ogg_size,f);
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}
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fclose(f);
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}
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}
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/* AUDIO engine shutdown */
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void gx_audio_Shutdown(void)
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{
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PauseOgg(1);
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StopOgg();
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ASND_Pause(1);
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ASND_End();
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if (Bg_music_ogg)
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{
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free(Bg_music_ogg);
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}
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}
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/***
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gx_audio_Update
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This function retrieves samples for the frame then set the next DMA parameters
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Parameters will be taken in account only when current DMA operation is over
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***/
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int gx_audio_Update(void)
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{
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if (!audio_sync)
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{
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/* Current available soundbuffer */
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s16 *sb = (s16 *)(soundbuffer[mixbuffer]);
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/* Retrieve audio samples (size must be multiple of 32 bytes) */
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int size = audio_update(sb) * 4;
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#ifdef LOG_TIMING
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if (prevtime && (frame_cnt < LOGSIZE - 1))
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{
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delta_samp[frame_cnt + 1] = size;
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}
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else
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{
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delta_samp[0] = size;
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}
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#endif
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/* Update DMA settings */
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DCFlushRange((void *)sb, size);
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AUDIO_InitDMA((u32) sb, size);
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mixbuffer = (mixbuffer + 1) % SOUND_BUFFER_NUM;
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audio_sync = 1;
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/* Start Audio DMA */
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/* this is called once to kick-off DMA from external memory to audio interface */
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/* DMA operation is automatically restarted when all samples have been sent. */
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/* If DMA settings are not updated at that time, previous sound buffer will be used. */
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/* Therefore we need to make sure frame emulation is completed before current DMA is */
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/* completed, by synchronizing frame emulation with DMA start and also by syncing it */
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/* with Video Interrupt and outputing a suitable number of samples per frame. */
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if (!audioStarted)
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{
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/* restart audio DMA */
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AUDIO_StopDMA();
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AUDIO_StartDMA();
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audioStarted = 1;
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}
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return SYNC_AUDIO;
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}
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return NO_SYNC;
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}
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/***
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gx_audio_Start
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This function restart the audio engine
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This is called when coming back from Main Menu
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***/
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void gx_audio_Start(void)
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{
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/* shutdown background music */
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PauseOgg(1);
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StopOgg();
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/* shutdown menu audio processing */
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ASND_Pause(1);
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ASND_End();
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AUDIO_StopDMA();
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AUDIO_RegisterDMACallback(NULL);
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DSP_Halt();
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/* DMA Interrupt callback */
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AUDIO_RegisterDMACallback(ai_callback);
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/* reset emulation audio processing */
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memset(soundbuffer, 0, 3 * SOUND_BUFFER_LEN);
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audioStarted = 0;
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mixbuffer = 0;
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audio_sync = 0;
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}
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/***
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gx_audio_Stop
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This function stops current Audio DMA process
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This is called when going back to Main Menu
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DMA need to be restarted when going back to the game (see above)
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***/
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void gx_audio_Stop(void)
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{
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/* restart menu audio processing */
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DSP_Unhalt();
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ASND_Init();
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ASND_Pause(0);
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/* play background music */
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if (Bg_music_ogg && !Shutdown)
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{
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PauseOgg(0);
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PlayOgg((char *)Bg_music_ogg, Bg_music_ogg_size, 0, OGG_INFINITE_TIME);
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SetVolumeOgg(((int)config.bgm_volume * 255) / 100);
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}
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}
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