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#include <SDL/SDL.h>
#include "common.h"
#include "../sound.h"
volatile unsigned int AudioFastForwarded;
#define DAMPEN_SAMPLE_COUNT (AUDIO_OUTPUT_BUFFER_SIZE / 32)
#ifdef SOUND_TO_FILE
FILE* WaveFile;
#endif
static inline void RenderSample(int16_t* Left, int16_t* Right)
{
int16_t LeftPart, RightPart;
uint32_t j;
for (j = 0; j < OUTPUT_FREQUENCY_DIVISOR; j++) {
ReGBA_LoadNextAudioSample(&LeftPart, &RightPart);
/* The GBA outputs in 12-bit sound. Make it louder. */
if (LeftPart > 2047) LeftPart = 2047;
else if (LeftPart < -2048) LeftPart = -2048;
*Left += LeftPart / OUTPUT_FREQUENCY_DIVISOR;
if (RightPart > 2047) RightPart = 2047;
else if (RightPart < -2048) RightPart = -2048;
*Right += RightPart / OUTPUT_FREQUENCY_DIVISOR;
}
}
void feed_buffer(void *udata, Uint8 *buffer, int len)
{
s16* stream = (s16*) buffer;
u32 Samples = ReGBA_GetAudioSamplesAvailable() / OUTPUT_FREQUENCY_DIVISOR;
u32 Requested = len / (2 * sizeof(s16));
u8 WasInUnderrun = Stats.InSoundBufferUnderrun;
Stats.InSoundBufferUnderrun = Samples < Requested * 2;
if (Stats.InSoundBufferUnderrun && !WasInUnderrun)
Stats.SoundBufferUnderrunCount++;
/* There must be AUDIO_OUTPUT_BUFFER_SIZE * 2 samples generated in order
* for the first AUDIO_OUTPUT_BUFFER_SIZE to be valid. Some sound is
* generated in the past from the future, and if the first
* AUDIO_OUTPUT_BUFFER_SIZE is grabbed before the core has had time to
* generate all of it (at AUDIO_OUTPUT_BUFFER_SIZE * 2), the end may
* still be silence, causing crackling. */
if (Samples < Requested * 2)
return; // Generate more sound first, please!
else
Stats.InSoundBufferUnderrun = 0;
s16* Next = stream;
// Take the first half of the sound.
uint32_t i;
for (i = 0; i < Requested / 2; i++)
{
s16 Left = 0, Right = 0;
RenderSample(&Left, &Right);
*Next++ = Left << 4;
*Next++ = Right << 4;
}
Samples -= Requested / 2;
// Discard as many samples as are generated in 1 frame, if fast-forwarding.
bool Skipped = false;
unsigned int VideoFastForwardedCopy = VideoFastForwarded;
if (VideoFastForwardedCopy != AudioFastForwarded)
{
unsigned int FramesToSkip = (VideoFastForwardedCopy > AudioFastForwarded)
? /* no overflow */ VideoFastForwardedCopy - AudioFastForwarded
: /* overflow */ 0x100 - (AudioFastForwarded - VideoFastForwardedCopy);
uint32_t SamplesToSkip = (uint32_t) (FramesToSkip * (OUTPUT_SOUND_FREQUENCY / 59.73f));
if (SamplesToSkip > Samples - (Requested * 3 - Requested / 2))
SamplesToSkip = Samples - (Requested * 3 - Requested / 2);
ReGBA_DiscardAudioSamples(SamplesToSkip * OUTPUT_FREQUENCY_DIVISOR);
Samples -= SamplesToSkip;
AudioFastForwarded = VideoFastForwardedCopy;
Skipped = true;
}
// Take the second half of the sound now.
for (i = 0; i < Requested - Requested / 2; i++)
{
s16 Left = 0, Right = 0;
RenderSample(&Left, &Right);
*Next++ = Left << 4;
*Next++ = Right << 4;
}
Samples -= Requested - Requested / 2;
// If we skipped sound, dampen the transition between the two halves.
if (Skipped)
{
for (i = 0; i < DAMPEN_SAMPLE_COUNT; i++)
{
uint_fast8_t j;
for (j = 0; j < 2; j++)
{
stream[Requested / 2 + i * 2 + j] = (int16_t) (
(int32_t) stream[Requested / 2 - i * 2 - 2 + j] * (DAMPEN_SAMPLE_COUNT - (int32_t) i) / (DAMPEN_SAMPLE_COUNT + 1)
+ (int32_t) stream[Requested / 2 + i * 2 + j] * ((int32_t) i + 1) / (DAMPEN_SAMPLE_COUNT + 1)
);
}
}
}
}
void init_sdlaudio()
{
SDL_AudioSpec spec;
spec.freq = OUTPUT_SOUND_FREQUENCY;
spec.format = AUDIO_S16SYS;
spec.channels = 2;
spec.samples = AUDIO_OUTPUT_BUFFER_SIZE;
spec.callback = feed_buffer;
spec.userdata = NULL;
if (SDL_OpenAudio(&spec, NULL) < 0) {
ReGBA_Trace("E: Failed to open audio: %s", SDL_GetError());
return;
}
SDL_PauseAudio(0);
}
signed int ReGBA_AudioUpdate()
{
return 0;
}
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