sdl_ndsaudio.c

SDL库 在进行视频显示程序spcaview安装时必须的库文件

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    [e-mail]
*/
#include "SDL_config.h"

/* Allow access to a raw mixing buffer */
#include <nds.h>
#include "SDL.h"
#include "SDL_endian.h"
#include "SDL_timer.h"
#include "SDL_audio.h"
#include "../SDL_audiomem.h"
#include "../SDL_audio_c.h"
#include "SDL_ndsaudio.h"
#include "soundcommon.h"


/* Audio driver functions */
static int NDS_OpenAudio(_THIS, SDL_AudioSpec *spec);
static void NDS_WaitAudio(_THIS);
static void NDS_PlayAudio(_THIS);
static Uint8 *NDS_GetAudioBuf(_THIS);
static void NDS_CloseAudio(_THIS);

/* Audio driver bootstrap functions */

u32 framecounter = 0,soundoffset = 0;
static SDL_AudioDevice *sdl_nds_audiodevice; 

//void SoundMixCallback(void *stream,u32 size)
//{
//	//printf("SoundMixCallback\n");
//	
//	Uint8 *buffer;
//	 
// 	buffer = sdl_nds_audiodevice->hidden->mixbuf;
//	memset(buffer, sdl_nds_audiodevice->spec.silence, size);
//	
//	if (!sdl_nds_audiodevice->paused){ 
//		 
//
//	//if (sdl_nds_audiodevice->convert.needed) {
//	//	int silence;
//
//	//	if (sdl_nds_audiodevice->convert.src_format == AUDIO_U8 ) { 
//	//		silence = 0x80;
//	//	} else {
//	//		silence =  0; 
//	//	}
//	//	memset(sdl_nds_audiodevice->convert.buf, silence, sdl_nds_audiodevice->convert.len);
//	//	sdl_nds_audiodevice->spec.callback(sdl_nds_audiodevice->spec.userdata,
//	//		(Uint8 *)sdl_nds_audiodevice->convert.buf,sdl_nds_audiodevice->convert.len);
//	//	SDL_ConvertAudio(&sdl_nds_audiodevice->convert);
//	//	memcpy(buffer, sdl_nds_audiodevice->convert.buf, sdl_nds_audiodevice->convert.len_cvt);
//	//} else 
//	{
//		sdl_nds_audiodevice->spec.callback(sdl_nds_audiodevice->spec.userdata, buffer, size);
//		//memcpy((Sint16 *)stream,buffer, size);
//	}
//
//	}
//
//	if(soundsystem->format == 8)
//	{
//		int i;
//		s32 *buffer32 = (s32 *)buffer; 
//		s32 *stream32 = (s32 *)stream;
//		for(i=0;i<size/4;i++){ *stream32++ = buffer32[i] ^ 0x80808080;}
//		//for(i = 0; i < size; i++)
//		//	((s8*)stream)[i]=(buffer[i]^0x80);
//	}
//	else
//	{
//		int i;
//		for(i = 0; i < size; i++){
//			//((short*)stream)[i] =(short)buffer[i] << 8;				// sound 8bit ---> buffer 16bit
//			//if (buffer[i] &0x80)
//				//((Sint16*)stream)[i] = 0xff00 | buffer[i];
//			((Sint16*)stream)[i] = (buffer[i] - 128) << 8;
//
//			//else
//			//	((Sint16*)stream)[i] = buffer[i];
//		}
//		//register signed char *pSrc =buffer;
//		//register short *pDest =stream;
//		//int x;
//		//			for (x=size; x>0; x--)
//		//			{
//		//				register short temp = (((short)*pSrc)-128)<<8;
//		//				pSrc++;
//		//				*pDest++ = temp;
//		//			}
//
//		//memcpy((Sint16 *)stream,buffer, size);
//	}
//}

void SoundMixCallback(void *stream,u32 len)
{
	SDL_AudioDevice *audio = (SDL_AudioDevice *)sdl_nds_audiodevice;

	/* Silence the buffer, since it's ours */
	SDL_memset(stream, audio->spec.silence, len);

	/* Only do soemthing if audio is enabled */
	if ( ! audio->enabled )
		return;

	if ( ! audio->paused ) {
		if ( audio->convert.needed ) {
			//fprintf(stderr,"converting audio\n");
			SDL_mutexP(audio->mixer_lock);
			(*audio->spec.callback)(audio->spec.userdata,
				(Uint8 *)audio->convert.buf,audio->convert.len);
			SDL_mutexV(audio->mixer_lock);
			SDL_ConvertAudio(&audio->convert);
			SDL_memcpy(stream,audio->convert.buf,audio->convert.len_cvt);
		} else {
			SDL_mutexP(audio->mixer_lock);
			(*audio->spec.callback)(audio->spec.userdata,
						(Uint8 *)stream, len);
			SDL_mutexV(audio->mixer_lock);
		}
	}
	return;
}
void MixSound(void)
{
	int remain;

	if(soundsystem->format == 8)
	{
		if((soundsystem->soundcursor + soundsystem->numsamples) > soundsystem->buffersize)
		{
			SoundMixCallback(&soundsystem->mixbuffer[soundsystem->soundcursor],soundsystem->buffersize - soundsystem->soundcursor);
			remain = soundsystem->numsamples - (soundsystem->buffersize - soundsystem->soundcursor);
			SoundMixCallback(soundsystem->mixbuffer,remain);
		}
		else
		{
			SoundMixCallback(&soundsystem->mixbuffer[soundsystem->soundcursor],soundsystem->numsamples);
		}
	}
	else
	{
		if((soundsystem->soundcursor + soundsystem->numsamples) > (soundsystem->buffersize >> 1))
		{
			SoundMixCallback(&soundsystem->mixbuffer[soundsystem->soundcursor << 1],(soundsystem->buffersize >> 1) - soundsystem->soundcursor);
			remain = soundsystem->numsamples - ((soundsystem->buffersize >> 1) - soundsystem->soundcursor);
			SoundMixCallback(soundsystem->mixbuffer,remain);
		}
		else
		{
			SoundMixCallback(&soundsystem->mixbuffer[soundsystem->soundcursor << 1],soundsystem->numsamples);
		}
	}
}

void InterruptHandler(void)
{
	framecounter++;
}
void FiFoHandler(void)
{
	u32 command;
	while ( !(REG_IPC_FIFO_CR & (IPC_FIFO_RECV_EMPTY)) ) 
	{
		command = REG_IPC_FIFO_RX;

		switch(command)
		{
		case FIFO_NONE:
			break;
		case UPDATEON_ARM9:
			REG_IME = 0;
			MixSound();
			REG_IME = 1;
			SendCommandToArm7(MIXCOMPLETE_ONARM9);
			break;
		}
	}
}





static int Audio_Available(void)
{
	return(1);
}

static void Audio_DeleteDevice(SDL_AudioDevice *device)
{
}

static SDL_AudioDevice *Audio_CreateDevice(int devindex)
{
	
	SDL_AudioDevice *this;

	/* Initialize all variables that we clean on shutdown */
	this = (SDL_AudioDevice *)malloc(sizeof(SDL_AudioDevice));
	if ( this ) {
		SDL_memset(this, 0, (sizeof *this));
		this->hidden = (struct SDL_PrivateAudioData *)
				SDL_malloc((sizeof *this->hidden));
	}
	if ( (this == NULL) || (this->hidden == NULL) ) {
		SDL_OutOfMemory();
		if ( this ) {
			SDL_free(this);
		}
		return(0);
	}
	SDL_memset(this->hidden, 0, (sizeof *this->hidden));

	/* Set the function pointers */
	this->OpenAudio = NDS_OpenAudio;
	this->WaitAudio = NDS_WaitAudio;
	this->PlayAudio = NDS_PlayAudio;
	this->GetAudioBuf = NDS_GetAudioBuf;
	this->CloseAudio = NDS_CloseAudio;

	this->free = Audio_DeleteDevice;
//fprintf(stderr,"Audio_CreateDevice\n");
	return this;
}

AudioBootStrap NDSAUD_bootstrap = {
	"nds", "NDS audio",
	Audio_Available, Audio_CreateDevice
};


void static NDS_WaitAudio(_THIS)
{
	//printf("NDS_WaitAudio\n");
}

static void NDS_PlayAudio(_THIS)
{
	//printf("playing audio\n");
	if (this->paused)
		return;
	
}

static Uint8 *NDS_GetAudioBuf(_THIS)
{
	return NULL;//(this->hidden->mixbuf); 
}

static void NDS_CloseAudio(_THIS)
{
/*	if ( this->hidden->mixbuf != NULL ) {
		SDL_FreeAudioMem(this->hidden->mixbuf);
		this->hidden->mixbuf = NULL;
	}*/ 
}

static int NDS_OpenAudio(_THIS, SDL_AudioSpec *spec)
{
	//printf("NDS_OpenAudio\n");
	int format = 0;
	//switch(spec->format&0xff) {
	//case  8: spec->format = AUDIO_S8;format=8; break;
	//case 16: spec->format = AUDIO_S16LSB;format=16; break;
	//default:
	//	SDL_SetError("Unsupported audio format");
	//	return(-1);
	//}
	switch (spec->format&~0x1000) {
		case AUDIO_S8:
			/* Signed 8-bit audio supported */
			format=8;
			break;
		case AUDIO_U8:
			spec->format ^= 0x80;format=8;
			break;
		case AUDIO_U16:
			/* Unsigned 16-bit audio unsupported, convert to S16 */
			spec->format ^=0x8000;format=16;
		case AUDIO_S16:
			/* Signed 16-bit audio supported */
			format=16;
			break;
	}
	/* Update the fragment size as size in bytes */
	SDL_CalculateAudioSpec(spec);

	/* Allocate mixing buffer */
	//this->hidden->mixlen = spec->size;
	//this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(this->hidden->mixlen);
	//if ( this->hidden->mixbuf == NULL ) {
	//	SDL_SetError("Out of Memory");
	//	return(-1);
	//} 

	SDL_NDSAudio_mutex = 0; 
	sdl_nds_audiodevice=this;
	
	irqInit();
	irqSet(IRQ_VBLANK,&InterruptHandler);
	irqSet(IRQ_FIFO_NOT_EMPTY,&FiFoHandler);
	irqEnable(IRQ_FIFO_NOT_EMPTY);
	
	REG_IPC_FIFO_CR = IPC_FIFO_ENABLE | IPC_FIFO_SEND_CLEAR | IPC_FIFO_RECV_IRQ;



	SoundSystemInit(spec->freq,spec->size,0,format);
	SoundStartMixer();

	
	return(1);
}