MIXERLIB: An audio mixer library based on the SDL library

Copyright (C) 1997-1999 Sam Lantinga

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Library General Public

License as published by the Free Software Foundation; either

version 2 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

Library General Public License for more details.

You should have received a copy of the GNU Library General Public

License along with this library; if not, write to the Free

Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

Sam Lantinga

5635-34 Springhouse Dr.

Pleasanton, CA 94588 (USA)

slouken@devolution.com

*/

#include <stdlib.h>

#include <string.h>

#include "SDL_endian.h"

#include "SDL_audio.h"

/* The music command hack is UNIX specific */

#ifndef unix

#undef CMD_MUSIC

#endif

#ifdef CMD_MUSIC

#include "music_cmd.h"

#endif

#ifdef WAV_MUSIC

#include "wavestream.h"

#endif

#ifdef MOD_MUSIC

# include "mikmod.h"

# if defined(LIBMIKMOD_VERSION) /* libmikmod 3.1.8 */

# define UNIMOD MODULE

# define MikMod_Init() MikMod_Init(NULL)

# define MikMod_LoadSong(a,b) Player_Load(a,b,0)

# define MikMod_FreeSong Player_Free

extern int MikMod_errno;

# else /* old MikMod 3.0.3 */

# define MikMod_strerror(x) _mm_errmsg[x])

# define MikMod_errno _mm_errno

# endif

#endif

#ifdef MID_MUSIC

#include "timidity.h"

#endif

#ifdef MP3_MUSIC

#include <smpeg/smpeg.h>

static SDL_AudioSpec used_mixer;

#endif

int volatile music_active = 1;

static int volatile music_stopped = 0;

static int music_loops = 0;

static char *music_cmd = NULL;

static int samplesize;

static int music_swap8;

static int music_swap16;

struct _Mix_Music {

enum {

MUS_CMD,

MUS_WAV,

MUS_MOD,

MUS_MID,

MUS_MP3

} type;

union {

#ifdef CMD_MUSIC

MusicCMD *cmd;

#endif

#ifdef WAV_MUSIC

WAVStream *wave;

#endif

#ifdef MOD_MUSIC

UNIMOD *module;

#endif

#ifdef MID_MUSIC

MidiSong *midi;

#endif

#ifdef MP3_MUSIC

SMPEG *mp3;

#endif

} data;

Mix_Fading fading;

int fade_volume;

int fade_step;

int fade_steps;

int error;

};

/* Used to calculate fading steps */

static int ms_per_step;

/* Support for hooking when the music has finished */

static void (*music_finished_hook)(void) = NULL;

void Mix_HookMusicFinished(void (*music_finished)(void))

{

SDL_LockAudio();

music_finished_hook = music_finished;

SDL_UnlockAudio();

}

/* Mixing function */

void music_mixer(void *udata, Uint8 *stream, int len)

{

if ( music_playing ) {

if ( music_stopped ) {

/* To avoid concurrency problems and the use of mutexes,

the music is always stopped from the sound thread */

lowlevel_halt(); /* This function sets music_playing to NULL */

return;

if ( music_playing->fading != MIX_NO_FADING ) {

if ( music_playing->fade_step++ < music_playing->fade_steps ) {

int fade_volume = music_playing->fade_volume;

int fade_step = music_playing->fade_step;

int fade_steps = music_playing->fade_steps;

/ fade_steps);

} else { /* Fading in */

Mix_VolumeMusic((fade_volume * fade_step) / fade_steps);

}

} else {

if ( music_playing->fading == MIX_FADING_OUT ) {

lowlevel_halt();

return;

}

}

if ( !Mix_PlayingMusic() ) {

/* Restart music if it has to loop */

if ( music_loops && --music_loops ) {

Mix_RewindMusic();

if ( lowlevel_play(music_playing) < 0 ) {

fprintf(stderr,"Warning: Music restart failed.\n");

music_stopped = 1; /* Something went wrong */

music_playing->fading = MIX_NO_FADING;

}

}

else if (music_finished_hook) {

lowlevel_halt();

music_finished_hook();

return;

}

if ( music_volume <= 0 ) { /* Don't mix if volume is null */

return;

}

switch (music_playing->type) {

#ifdef CMD_MUSIC

case MUS_CMD:

/* The playing is done externally */

break;

#endif

#ifdef WAV_MUSIC

case MUS_WAV:

WAVStream_PlaySome(stream, len);

break;

#endif

#ifdef MOD_MUSIC

case MUS_MOD:

VC_WriteBytes((SBYTE *)stream, len);

if ( music_swap8 ) {

Uint8 *dst;

dst = stream;

for ( i=len; i; --i ) {

*dst++ ^= 0x80;

}

} else

if ( music_swap16 ) {

Uint8 *dst, tmp;

dst = stream;

for ( i=(len/2); i; --i ) {

tmp = dst[0];

dst[0] = dst[1];

dst[1] = tmp;

dst += 2;

}

}

break;

#endif

#ifdef MID_MUSIC

case MUS_MID:

Timidity_PlaySome(stream, len/samplesize);

break;

#endif

#ifdef MP3_MUSIC

case MUS_MP3:

SMPEG_playAudio(music_playing->data.mp3, stream, len);

break;

#endif

default:

/* Unknown music type?? */

break;

}

}

}

/* Initialize the music players with a certain desired audio format */

int open_music(SDL_AudioSpec *mixer)

{

int music_error;

music_error = 0;

#ifdef WAV_MUSIC

if ( WAVStream_Init(mixer) < 0 ) {

++music_error;

}

#endif

#ifdef MOD_MUSIC

/* Set the MikMod music format */

music_swap8 = 0;

music_swap16 = 0;

switch (mixer->format) {

case AUDIO_U8:

case AUDIO_S8: {

if ( mixer->format == AUDIO_S8 ) {

music_swap8 = 1;

}

md_mode = 0;

}

break;

case AUDIO_S16LSB:

case AUDIO_S16MSB: {

/* See if we need to correct MikMod mixing */

#if SDL_BYTEORDER == SDL_LIL_ENDIAN

if ( mixer->format == AUDIO_S16MSB ) {

#else

if ( mixer->format == AUDIO_S16LSB ) {

#endif

music_swap16 = 1;

}

md_mode = DMODE_16BITS;

}

break;

default: {

++music_error;

}

}

if ( mixer->channels > 1 ) {

if ( mixer->channels > 2 ) {

++music_error;

}

md_mode |= DMODE_STEREO;

}

samplesize = mixer->size/mixer->samples;

md_mixfreq = mixer->freq;

md_device = 0;

md_volume = 96;

md_musicvolume = 128;

md_sndfxvolume = 128;

md_pansep = 128;

md_reverb = 0;

MikMod_RegisterAllLoaders();

MikMod_RegisterAllDrivers();

if ( MikMod_Init() ) {

++music_error;

}

#endif

#ifdef MID_MUSIC

if ( Timidity_Init(mixer->freq,

mixer->format, mixer->channels, mixer->samples) == 0 ) {

timidity_ok = 1;

} else {

timidity_ok = 0;

}

#endif

#ifdef MP3_MUSIC

/* Keep a copy of the mixer */

used_mixer = *mixer;

#endif

if ( music_error ) {

return(-1);

}

Mix_VolumeMusic(SDL_MIX_MAXVOLUME);

return(0);

}

/* Load a music file */

Mix_Music *Mix_LoadMUS(const char *file)

{

FILE *fp;

Mix_Music *music;

/* Figure out what kind of file this is */

fp = fopen(file, "rb");

if ( (fp == NULL) || !fread(magic, 4, 1, fp) ) {

if ( fp != NULL ) {

fclose(fp);

}

return(NULL);

}

magic[4] = '\0';

fclose(fp);

/* Allocate memory for the music structure */

music = (Mix_Music *)malloc(sizeof(Mix_Music));

if ( music == NULL ) {

return(NULL);

}

music->error = 0;

#ifdef CMD_MUSIC

if ( music_cmd ) {

music->type = MUS_CMD;

music->data.cmd = MusicCMD_LoadSong(music_cmd, file);

if ( music->data.cmd == NULL ) {

music->error = 1;

}

} else

#endif

#ifdef WAV_MUSIC

/* WAVE files have the magic four bytes "RIFF"

AIFF files have the magic 12 bytes "FORM" XXXX "AIFF"

*/

if ( (strcmp(magic, "RIFF") == 0) || (strcmp(magic, "FORM") == 0) ) {

music->type = MUS_WAV;

music->data.wave = WAVStream_LoadSong(file, magic);

if ( music->data.wave == NULL ) {

music->error = 1;

}

} else

#endif

#ifdef MID_MUSIC

/* MIDI files have the magic four bytes "MThd" */

if ( strcmp(magic, "MThd") == 0 ) {

music->type = MUS_MID;

if ( timidity_ok ) {

music->data.midi = Timidity_LoadSong((char *)file);

if ( music->data.midi == NULL ) {

music->error = 1;

}

}

else {

music->error = 1;

}

} else

#endif

#ifdef MP3_MUSIC

if ( magic[0]==0xFF && (magic[1]&0xF0)==0xF0) {

SMPEG_Info info;

music->type = MUS_MP3;

music->data.mp3 = SMPEG_new(file, &info, 0);

if(!info.has_audio){

music->error = 1;

}else{

SMPEG_actualSpec(music->data.mp3, &used_mixer);

}

} else

#endif

#ifdef MOD_MUSIC

if ( 1 ) {

music->type = MUS_MOD;

music->data.module = MikMod_LoadSong((char *)file, 64);

if ( music->data.module == NULL ) {

music->error = 1;

}

} else

#endif

{

music->error = 1;

}

if ( music->error ) {

free(music);

music = NULL;

}

return(music);

}

/* Free a music chunk previously loaded */

void Mix_FreeMusic(Mix_Music *music)

{

if ( music ) {

/* Caution: If music is playing, mixer will crash */

if ( music->fading == MIX_FADING_OUT ) {

/* Wait for the fade out to finish */

SDL_Delay(100);

} else {

Mix_HaltMusic(); /* Stop it immediately */

}

}

switch (music->type) {

#ifdef CMD_MUSIC

case MUS_CMD:

MusicCMD_FreeSong(music->data.cmd);

break;

#endif

#ifdef WAV_MUSIC

case MUS_WAV:

WAVStream_FreeSong(music->data.wave);

break;

#endif

#ifdef MOD_MUSIC

case MUS_MOD:

MikMod_FreeSong(music->data.module);

break;

#endif

#ifdef MID_MUSIC

case MUS_MID:

Timidity_FreeSong(music->data.midi);

break;

#endif

#ifdef MP3_MUSIC

SMPEG_delete(music->data.mp3);

break;

#endif

default:

/* Unknown music type?? */

break;

}

free(music);

}

}

switch (music->type) {

#ifdef CMD_MUSIC

case MUS_CMD:

MusicCMD_SetVolume(music_volume);

MusicCMD_Start(music->data.cmd);

break;

#endif

#ifdef WAV_MUSIC

case MUS_WAV:

WAVStream_SetVolume(music_volume);

WAVStream_Start(music->data.wave);

break;

#endif

#ifdef MOD_MUSIC

case MUS_MOD:

Player_Start(music->data.module);

Player_SetPosition(0);

break;

#endif

#ifdef MID_MUSIC

case MUS_MID:

Timidity_SetVolume(music_volume);

Timidity_Start(music->data.midi);

break;

#endif

#ifdef MP3_MUSIC

SMPEG_enableaudio(music->data.mp3,1);

SMPEG_enablevideo(music->data.mp3,0);

SMPEG_setvolume(music->data.mp3,((float)music_volume/(float)MIX_MAX_VOLUME)*100.0);

SMPEG_play(music->data.mp3);

break;

#endif

default:

/* Unknown music type?? */

return(-1);

}

return(0);

}

/* Play a music chunk. Returns 0, or -1 if there was an error.

*/

int Mix_PlayMusic(Mix_Music *music, int loops)

{

/* Don't play null pointers :-) */

if ( music == NULL ) {

return(-1);

}

/* If the current music is fading out, wait for the fade to complete */

while ( music_playing && !music_stopped && music_playing->fading==MIX_FADING_OUT ) {

SDL_Delay(100);

}

music_playing->fading = MIX_NO_FADING;

return(0);

}

/* Fade in a music over "ms" milliseconds */

int Mix_FadeInMusic(Mix_Music *music, int loops, int ms)

{

if ( music && music_volume > 0 ) { /* No need to fade if we can't hear it */

music->fade_volume = music_volume;

music_volume = 0;

music_playing->fade_step = 0;

music_playing->fade_steps = ms/ms_per_step;

music_playing->fading = MIX_FADING_IN;

}

return(0);

}

/* Set the music volume */

int Mix_VolumeMusic(int volume)

{

int prev_volume;

prev_volume = music_volume;

if ( volume < 0 ) {

volume = 0;

}

if ( volume > SDL_MIX_MAXVOLUME ) {

volume = SDL_MIX_MAXVOLUME;

}

music_volume = volume;

case MUS_CMD:

MusicCMD_SetVolume(music_volume);

break;

#endif

#ifdef WAV_MUSIC

case MUS_WAV:

WAVStream_SetVolume(music_volume);

break;

#endif

#ifdef MOD_MUSIC

#endif

#ifdef MID_MUSIC

case MUS_MID:

Timidity_SetVolume(music_volume);

break;

#endif

#ifdef MP3_MUSIC

case MUS_MP3:

SMPEG_setvolume(music_playing->data.mp3,((float)music_volume/(float)MIX_MAX_VOLUME)*100.0);

break;

default:

/* Unknown music type?? */

break;

}

}

return(prev_volume);

}

case MUS_CMD:

MusicCMD_Stop(music_playing->data.cmd);

break;

#endif

#ifdef WAV_MUSIC

case MUS_WAV:

WAVStream_Stop();

break;

#endif

#ifdef MOD_MUSIC

case MUS_MOD:

Player_Stop();

break;

#endif

#ifdef MID_MUSIC

case MUS_MID:

Timidity_Stop();

break;

#endif

#ifdef MP3_MUSIC

case MUS_MP3:

SMPEG_stop(music_playing->data.mp3);

break;

default:

/* Unknown music type?? */

return;

}

music_volume = music_playing->fade_volume;

music_playing->fading = MIX_NO_FADING;

music_stopped = 0;

}

/* Halt playing of music */

int Mix_HaltMusic(void)

{

if ( music_playing && !music_stopped ) {

/* Mark the music to be stopped from the sound thread */

music_stopped = 1;

/* Wait for it to be actually stopped */

}

return(0);

}

/* Progressively stop the music */

int Mix_FadeOutMusic(int ms)

{

if ( music_playing && !music_stopped &&

(music_playing->fading == MIX_NO_FADING) ) {

music_playing->fading = MIX_FADING_OUT;

music_playing->fade_volume = music_volume;

music_playing->fade_step = 0;

music_playing->fade_steps = ms/ms_per_step;

return(1);

}

}

return(0);

}

Mix_Fading Mix_FadingMusic(void)

{

return music_playing->fading;

return MIX_NO_FADING;

}

/* Pause/Resume the music stream */

void Mix_PauseMusic(void)

{

}

}

void Mix_ResumeMusic(void)

{

}

}

void Mix_RewindMusic(void)

{

#ifdef MOD_MUSIC

case MUS_MOD:

Player_Start(music_playing->data.module);

Player_SetPosition(0);

break;

#endif

#ifdef MP3_MUSIC

case MUS_MP3:

SMPEG_rewind(music_playing->data.mp3);

break;

#endif

}

}

}

int Mix_PausedMusic(void)

{

}

switch (music_playing->type) {

#ifdef CMD_MUSIC

case MUS_CMD:

if (!MusicCMD_Active(music_playing->data.cmd)) {

}

break;

#endif

#ifdef WAV_MUSIC

case MUS_WAV:

if ( ! WAVStream_Active() ) {

}

break;

#endif

#ifdef MOD_MUSIC

case MUS_MOD:

if ( ! Player_Active() ) {

}

break;

#endif

#ifdef MID_MUSIC

case MUS_MID:

if ( ! Timidity_Active() ) {

}

break;

#endif

#ifdef MP3_MUSIC

case MUS_MP3:

if(SMPEG_status(music_playing->data.mp3)!=SMPEG_PLAYING)

break;

#endif

default:

break;

return(1);

}