fceux/src/drivers/sdl/sdl-sound.cpp

/* FCE Ultra - NES/Famicom Emulator
 *
 * Copyright notice for this file:
 *  Copyright (C) 2002 Xodnizel
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

/// \file
/// \brief Handles sound emulation using the SDL.

#include "sdl.h"

#include "../common/configSys.h"
#include "../../utils/memory.h"

#include <cstdio>
#include <cstring>
#include <cstdlib>

extern Config *g_config;

static volatile int *s_Buffer = 0;
static unsigned int s_BufferSize;
static unsigned int s_BufferRead;
static unsigned int s_BufferWrite;
static volatile unsigned int s_BufferIn;

static int s_mute = 0;


/**
 * Callback from the SDL to get and play audio data.
 */
static void
fillaudio(void *udata,
			uint8 *stream,
			int len)
{
	static int16_t sample = 0;
	int16 *tmps = (int16*)stream;
	len >>= 1;
	while (len)
	{
		if (s_BufferIn)
		{
			sample = s_Buffer[s_BufferRead];
			s_BufferRead = (s_BufferRead + 1) % s_BufferSize;
			s_BufferIn--;
		} else {
			// Retain last known sample value, helps avoid clicking
         // noise when sound system is starved of audio data.
			//sample = 0; 
			//bufStarveDetected = 1;
		}

		*tmps = sample;
		tmps++;
		len--;
	}
}

/**
 * Initialize the audio subsystem.
 */
int
InitSound()
{
	int sound, soundrate, soundbufsize, soundvolume, soundtrianglevolume, soundsquare1volume, soundsquare2volume, soundnoisevolume, soundpcmvolume, soundq;
	SDL_AudioSpec spec;
	const char *driverName;

	g_config->getOption("SDL.Sound", &sound);
	if (!sound) 
	{
		return 0;
	}

	memset(&spec, 0, sizeof(spec));
	if (SDL_InitSubSystem(SDL_INIT_AUDIO) < 0) 
	{
		puts(SDL_GetError());
		KillSound();
		return 0;
	}

	// load configuration variables
	g_config->getOption("SDL.Sound.Rate", &soundrate);
	g_config->getOption("SDL.Sound.BufSize", &soundbufsize);
	g_config->getOption("SDL.Sound.Volume", &soundvolume);
	g_config->getOption("SDL.Sound.Quality", &soundq);
	g_config->getOption("SDL.Sound.TriangleVolume", &soundtrianglevolume);
	g_config->getOption("SDL.Sound.Square1Volume", &soundsquare1volume);
	g_config->getOption("SDL.Sound.Square2Volume", &soundsquare2volume);
	g_config->getOption("SDL.Sound.NoiseVolume", &soundnoisevolume);
	g_config->getOption("SDL.Sound.PCMVolume", &soundpcmvolume);

	spec.freq = soundrate;
	spec.format = AUDIO_S16SYS;
	spec.channels = 1;
	spec.samples = 512;
	spec.callback = fillaudio;
	spec.userdata = 0;

	s_BufferSize = soundbufsize * soundrate / 1000;

	// For safety, set a bare minimum:
	if (s_BufferSize < spec.samples * 2)
	{
		s_BufferSize = spec.samples * 2;
	}

	s_Buffer = (int *)FCEU_dmalloc(sizeof(int) * s_BufferSize);

	if (!s_Buffer)
	{
		return 0;
	}
	s_BufferRead = s_BufferWrite = s_BufferIn = 0;

	if (SDL_OpenAudio(&spec, 0) < 0)
	{
		puts(SDL_GetError());
		KillSound();
		return 0;
   }
	SDL_PauseAudio(0);

	driverName = SDL_GetCurrentAudioDriver();

	if ( driverName )
	{
		fprintf(stderr, "Loading SDL sound with %s driver...\n", driverName);
	}

	FCEUI_SetSoundVolume(soundvolume);
	FCEUI_SetSoundQuality(soundq);
	FCEUI_Sound(soundrate);
	FCEUI_SetTriangleVolume(soundtrianglevolume);
	FCEUI_SetSquare1Volume(soundsquare1volume);
	FCEUI_SetSquare2Volume(soundsquare2volume);
	FCEUI_SetNoiseVolume(soundnoisevolume);
	FCEUI_SetPCMVolume(soundpcmvolume);
	return 1;
}


/**
 * Returns the size of the audio buffer.
 */
uint32
GetMaxSound(void)
{
	return(s_BufferSize);
}

/**
 * Returns the amount of free space in the audio buffer.
 */
uint32
GetWriteSound(void)
{
	return(s_BufferSize - s_BufferIn);
}

/**
 * Send a sound clip to the audio subsystem.
 */
void
WriteSound(int32 *buf,
           int Count)
{
	extern int EmulationPaused;
	if (EmulationPaused == 0)
   {
		int waitCount = 0;

		while(Count)
		{
			while(s_BufferIn == s_BufferSize) 
			{
				SDL_Delay(1); waitCount++;

				if ( waitCount > 1000 )
				{
					printf("Error: Sound sink is not draining... Breaking out of audio loop to prevent lockup.\n");
					return;
				}
			}

			s_Buffer[s_BufferWrite] = *buf;
			Count--;
			s_BufferWrite = (s_BufferWrite + 1) % s_BufferSize;
            
			SDL_LockAudio();
			s_BufferIn++;
			SDL_UnlockAudio();
            
			buf++;
		}
   }
}

/**
 * Pause (1) or unpause (0) the audio output.
 */
void
SilenceSound(int n)
{ 
	SDL_PauseAudio(n);   
}

/**
 * Shut down the audio subsystem.
 */
int
KillSound(void)
{
	FCEUI_Sound(0);
	SDL_CloseAudio();
	SDL_QuitSubSystem(SDL_INIT_AUDIO);
	if(s_Buffer) {
		free((void *)s_Buffer);
		s_Buffer = 0;
	}
	return 0;
}


/**
 * Adjust the volume either down (-1), up (1), or to the default (0).
 * Unmutes if mute was active before.
 */
void
FCEUD_SoundVolumeAdjust(int n)
{
	int soundvolume;
	g_config->getOption("SDL.Sound.Volume", &soundvolume);

	switch(n) {
	case -1:
		soundvolume -= 10;
		if(soundvolume < 0) {
			soundvolume = 0;
		}
		break;
	case 0:
		soundvolume = 100;
		break;
	case 1:
		soundvolume += 10;
		if(soundvolume > 150) {
			soundvolume = 150;
		}
		break;
	}

	s_mute = 0;
	FCEUI_SetSoundVolume(soundvolume);
	g_config->setOption("SDL.Sound.Volume", soundvolume);

	FCEU_DispMessage("Sound volume %d.",0, soundvolume);
}

/**
 * Toggles the sound on or off.
 */
void
FCEUD_SoundToggle(void)
{
	if(s_mute) {
		int soundvolume;
		g_config->getOption("SDL.SoundVolume", &soundvolume);

		s_mute = 0;
		FCEUI_SetSoundVolume(soundvolume);
		FCEU_DispMessage("Sound mute off.",0);
	} else {
		s_mute = 1;
		FCEUI_SetSoundVolume(0);
		FCEU_DispMessage("Sound mute on.",0);
	}
}