mirror of
https://github.com/dborth/vbagx.git
synced 2024-12-27 11:11:50 +01:00
106 lines
2.1 KiB
C++
106 lines
2.1 KiB
C++
/****************************************************************************
|
|
* Visual Boy Advance GX
|
|
*
|
|
* Tantric September 2008
|
|
*
|
|
* audio.cpp
|
|
*
|
|
* Head and tail audio mixer
|
|
***************************************************************************/
|
|
|
|
#include <gccore.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
|
|
/** Locals **/
|
|
static int head = 0;
|
|
static int tail = 0;
|
|
|
|
#define MIXBUFFSIZE 0x10000
|
|
static u8 mixerdata[MIXBUFFSIZE];
|
|
#define MIXERMASK ((MIXBUFFSIZE >> 2) - 1)
|
|
|
|
static u8 soundbuffer[3200] ATTRIBUTE_ALIGN(32);
|
|
|
|
/****************************************************************************
|
|
* MIXER_AddSamples
|
|
*
|
|
* Upsample from 11025 to 48000
|
|
* 11025 == 15052
|
|
* 22050 == 30106
|
|
* 44100 == 60211
|
|
*
|
|
* Audio officianados should look away now !
|
|
****************************************************************************/
|
|
void MIXER_AddSamples( u8 *sampledata, int len )
|
|
{
|
|
u32 *src = (u32 *)sampledata;
|
|
u32 *dst = (u32 *)mixerdata;
|
|
u32 intlen = (3200 >> 2);
|
|
u32 fixofs = 0;
|
|
u32 fixinc;
|
|
|
|
if ( !len )
|
|
fixinc = 30106;
|
|
else
|
|
fixinc = 60211;
|
|
|
|
do
|
|
{
|
|
// Do simple linear interpolate
|
|
dst[head++] = src[fixofs >> 16];
|
|
head &= MIXERMASK;
|
|
fixofs += fixinc;
|
|
}
|
|
while( --intlen );
|
|
}
|
|
|
|
/****************************************************************************
|
|
* MIXER_GetSamples
|
|
****************************************************************************/
|
|
int MIXER_GetSamples( u8 *dstbuffer, int maxlen )
|
|
{
|
|
u32 *src = (u32 *)mixerdata;
|
|
u32 *dst = (u32 *)dstbuffer;
|
|
u32 intlen = maxlen >> 2;
|
|
|
|
memset(dstbuffer, 0, maxlen);
|
|
|
|
while( ( head != tail ) && intlen )
|
|
{
|
|
*dst++ = src[tail++];
|
|
tail &= MIXERMASK;
|
|
intlen--;
|
|
}
|
|
|
|
return 3200;
|
|
}
|
|
|
|
static void AudioPlayer()
|
|
{
|
|
AUDIO_StopDMA();
|
|
MIXER_GetSamples(soundbuffer, 3200);
|
|
DCFlushRange(soundbuffer,3200);
|
|
AUDIO_InitDMA((u32)soundbuffer,3200);
|
|
AUDIO_StartDMA();
|
|
}
|
|
|
|
void InitialiseSound()
|
|
{
|
|
AUDIO_Init(NULL); // Start audio subsystem
|
|
AUDIO_SetDSPSampleRate(AI_SAMPLERATE_48KHZ);
|
|
AUDIO_RegisterDMACallback(AudioPlayer);
|
|
memset(soundbuffer, 0, 3200);
|
|
}
|
|
|
|
void StopAudio()
|
|
{
|
|
AUDIO_StopDMA();
|
|
}
|
|
|
|
void StartAudio()
|
|
{
|
|
AUDIO_StartDMA();
|
|
}
|