frodo-wii/Src/gcaudio.c
2009-04-05 14:38:04 +00:00

149 lines
3.7 KiB
C

/****************************************************************************
* FCE Ultra 0.98.12
* Nintendo Wii/Gamecube Port
*
* Tantric September 2008
* eke-eke October 2008
*
* gcaudio.c
*
* Audio driver
****************************************************************************/
#include <gccore.h>
#include <string.h>
#define SAMPLERATE 32000
#define MIXBUFSIZE_BYTES 16000
#define MIXBUFSIZE_SHORT (MIXBUFSIZE_BYTES / 2)
#define MIXBUFSIZE_WORDS (MIXBUFSIZE_BYTES / 4)
#define SOUNDBUFSIZE 2048
static u8 ConfigRequested = 0;
static u8 soundbuffer[2][SOUNDBUFSIZE] ATTRIBUTE_ALIGN(32);
static u8 mixbuffer[MIXBUFSIZE_BYTES];
static int mixhead = 0;
static int mixtail = 0;
static int whichab = 0;
static int IsPlaying = 0;
/****************************************************************************
* MixerCollect
*
* Collects sound samples from mixbuffer and puts them into outbuffer
* Makes sure to align them to 32 bytes for AUDIO_InitDMA
***************************************************************************/
static int MixerCollect( u8 *outbuffer, int len )
{
u32 *dst = (u32 *)outbuffer;
u32 *src = (u32 *)mixbuffer;
int done = 0;
// Always clear output buffer
memset(outbuffer, 0, len);
while ( ( mixtail != mixhead ) && ( done < len ) )
{
*dst++ = src[mixtail++];
if (mixtail == MIXBUFSIZE_WORDS) mixtail = 0;
done += 4;
}
// Realign to 32 bytes for DMA
mixtail -= ((done&0x1f) >> 2);
if (mixtail < 0)
mixtail += MIXBUFSIZE_WORDS;
done &= ~0x1f;
return done;
}
/****************************************************************************
* AudioSwitchBuffers
*
* Manages which buffer is played next
***************************************************************************/
static void AudioSwitchBuffers()
{
if ( !ConfigRequested )
{
int len = MixerCollect( soundbuffer[whichab], SOUNDBUFSIZE );
if (len == 0)
return;
DCFlushRange(soundbuffer[whichab], len);
AUDIO_InitDMA((u32)soundbuffer[whichab], len);
AUDIO_StartDMA();
whichab ^= 1;
IsPlaying = 1;
}
else IsPlaying = 0;
}
/****************************************************************************
* InitialiseAudio
*
* Initializes sound system on first load of emulator
***************************************************************************/
void InitialiseAudio()
{
AUDIO_Init(NULL); // Start audio subsystem
AUDIO_SetDSPSampleRate(AI_SAMPLERATE_32KHZ);
AUDIO_RegisterDMACallback( AudioSwitchBuffers );
memset(soundbuffer, 0, SOUNDBUFSIZE*2);
memset(mixbuffer, 0, MIXBUFSIZE_BYTES);
}
/****************************************************************************
* StopAudio
*
* Pause audio output when returning to menu
***************************************************************************/
void StopAudio()
{
AUDIO_StopDMA();
IsPlaying = 0;
}
/****************************************************************************
* ResetAudio
*
* Reset audio output when loading a new game
***************************************************************************/
void ResetAudio()
{
memset(soundbuffer, 0, SOUNDBUFSIZE*2);
memset(mixbuffer, 0, MIXBUFSIZE_BYTES);
mixhead = mixtail = 0;
}
/****************************************************************************
* PlaySound
*
* Puts incoming mono samples into mixbuffer
* Splits mono samples into two channels (stereo)
****************************************************************************/
void PlaySound( int16_t *Buffer, int count )
{
u32 *dst = (u32 *)mixbuffer;
int i;
for( i = 0; i < count; i++ )
{
u16 sample;
sample = (Buffer[i] & 0xffff);
dst[mixhead++] = sample | ( sample << 16);
if (mixhead == MIXBUFSIZE_WORDS)
mixhead = 0;
}
// Restart Sound Processing if stopped
if (IsPlaying == 0)
{
AudioSwitchBuffers ();
}
}