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sdl-sound.cpp

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/* 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

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

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "sdl.h"

#include "../common/configSys.h"
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
00046 fillaudio(void *udata,
          uint8 *stream,
          int len)
{
    int16 *tmps = (int16*)stream;
    len >>= 1;
      // debug code
      //printf("s_BufferIn: %i s_BufferWrite = %i s_BufferRead = %i s_BufferSize = %i\n",
      // s_BufferIn, s_BufferWrite, s_BufferRead, s_BufferSize);
      
      // ensure that we're not writing garbage data to the soundcard
      if(s_BufferWrite > s_BufferRead)
            s_BufferWrite = s_BufferRead; 
            
    while(len) {
        int16 sample = 0;
        if(s_BufferIn) {
            sample = s_Buffer[s_BufferRead];
            s_BufferRead = (s_BufferRead + 1) % s_BufferSize;
            s_BufferIn--;
        } else {
            sample = 0;
        }

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

/**
 * Initialize the audio subsystem.
 */
int
00080 InitSound(FCEUGI *gi)
{
    int sound, soundrate, soundbufsize, soundvolume, soundtrianglevolume, soundsquare1volume, soundsquare2volume, soundnoisevolume, soundpcmvolume, soundq;
    SDL_AudioSpec spec;

    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.SoundRate", &soundrate);
    g_config->getOption("SDL.SoundBufSize", &soundbufsize);
    g_config->getOption("SDL.SoundVolume", &soundvolume);
    g_config->getOption("SDL.SoundQuality", &soundq);
    g_config->getOption("SDL.TriangleVolume", &soundtrianglevolume);
    g_config->getOption("SDL.Square1Volume", &soundsquare1volume);
    g_config->getOption("SDL.Square2Volume", &soundsquare2volume);
    g_config->getOption("SDL.NoiseVolume", &soundnoisevolume);
    g_config->getOption("SDL.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 *)malloc(sizeof(int) * s_BufferSize);
    s_BufferRead = s_BufferWrite = s_BufferIn = 0;

    //printf("SDL Size: %d, Internal size: %d\n",spec.samples,s_BufferSize);

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

    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
00149 GetMaxSound(void)
{
    return(s_BufferSize);
}

/**
 * Returns the amount of free space in the audio buffer.
 */
uint32
00158 GetWriteSound(void)
{
    return(s_BufferSize - s_BufferIn);
}

/**
 * Send a sound clip to the audio subsystem.
 */
void
00167 WriteSound(int32 *buf,
           int Count)
{
    extern int EmulationPaused;
    if (EmulationPaused == 0)
        while(Count)
            {
            while(s_BufferIn == s_BufferSize) 
                  {
                SDL_Delay(1);
            }

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

/**
 * Pause (1) or unpause (0) the audio output.
 */
void
00191 SilenceSound(int n)
{ 
    SDL_PauseAudio(n);   
}

/**
 * Shut down the audio subsystem.
 */
int
00200 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
00218 FCEUD_SoundVolumeAdjust(int n)
{
    int soundvolume;
    g_config->getOption("SDL.SoundVolume", &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.SoundVolume", soundvolume);

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

/**
 * Toggles the sound on or off.
 */
void
00252 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.");
    } else {
        s_mute = 1;
        FCEUI_SetSoundVolume(0);
        FCEU_DispMessage("Sound mute on.");
    }
}

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