mdriver.c

SDL_mixer 是一个基于 SDL 的混音器

/*	MikMod sound library
	(c) 1998, 1999 Miodrag Vallat and others - see file AUTHORS for
	complete list.

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

/*==============================================================================

  $Id: mdriver.c 346 2001-09-11 18:49:18Z slouken $

  These routines are used to access the available soundcard drivers.

==============================================================================*/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#ifdef unix
#include <pwd.h>
#include <sys/stat.h>
#endif

#include <string.h>
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif

#include "mikmod_internals.h"


static	MDRIVER *firstdriver=NULL;
		MDRIVER *md_driver=NULL;
extern	MODULE *pf; /* modfile being played */

		UWORD md_device         = 0;
		UWORD md_mixfreq        = 44100;
		UWORD md_mode           = DMODE_STEREO | DMODE_16BITS | DMODE_SURROUND
		                         |DMODE_SOFT_MUSIC | DMODE_SOFT_SNDFX;
		UBYTE md_pansep         = 128; /* 128 == 100% (full left/right) */
		UBYTE md_reverb         = 6; /* Reverb */
		UBYTE md_volume         = 128;  /* Global sound volume (0-128) */
		UBYTE md_musicvolume    = 128; /* volume of song */
		UBYTE md_sndfxvolume    = 128; /* volume of sound effects */
		UWORD md_bpm            = 125;

/* Do not modify the numchn variables yourself!  use MD_SetVoices() */
		UBYTE md_numchn=0,md_sngchn=0,md_sfxchn=0;
		UBYTE md_hardchn=0,md_softchn=0;

		void (*md_player)(void) = Player_HandleTick;
static	BOOL  isplaying=0, initialized = 0;
static	UBYTE *sfxinfo;
static	int sfxpool;

static	SAMPLE **md_sample = NULL;

/* Previous driver in use */
static	UWORD idevice;

/* Limits the number of hardware voices to the specified amount.
   This function should only be used by the low-level drivers. */
static	void LimitHardVoices(int limit)
{
	int t=0;

	if (!(md_mode & DMODE_SOFT_SNDFX) && (md_sfxchn>limit)) md_sfxchn=limit;
	if (!(md_mode & DMODE_SOFT_MUSIC) && (md_sngchn>limit)) md_sngchn=limit;

	if (!(md_mode & DMODE_SOFT_SNDFX))
		md_hardchn=md_sfxchn;
	else
		md_hardchn=0;

	if (!(md_mode & DMODE_SOFT_MUSIC)) md_hardchn += md_sngchn;

	while (md_hardchn>limit) {
		if (++t & 1) {
			if (!(md_mode & DMODE_SOFT_SNDFX) && (md_sfxchn>4)) md_sfxchn--;
		} else {
			if (!(md_mode & DMODE_SOFT_MUSIC) && (md_sngchn>8)) md_sngchn--;
		}

		if (!(md_mode & DMODE_SOFT_SNDFX))
			md_hardchn=md_sfxchn;
		else
			md_hardchn=0;

		if (!(md_mode & DMODE_SOFT_MUSIC))
			md_hardchn+=md_sngchn;
	}
	md_numchn=md_hardchn+md_softchn;
}

/* Limits the number of hardware voices to the specified amount.
   This function should only be used by the low-level drivers. */
static	void LimitSoftVoices(int limit)
{
	int t=0;

	if ((md_mode & DMODE_SOFT_SNDFX) && (md_sfxchn>limit)) md_sfxchn=limit;
	if ((md_mode & DMODE_SOFT_MUSIC) && (md_sngchn>limit)) md_sngchn=limit;

	if (md_mode & DMODE_SOFT_SNDFX)
		md_softchn=md_sfxchn;
	else
		md_softchn=0;

	if (md_mode & DMODE_SOFT_MUSIC) md_softchn+=md_sngchn;

	while (md_softchn>limit) {
		if (++t & 1) {
			if ((md_mode & DMODE_SOFT_SNDFX) && (md_sfxchn>4)) md_sfxchn--;
		} else {
			if ((md_mode & DMODE_SOFT_MUSIC) && (md_sngchn>8)) md_sngchn--;
		}

		if (!(md_mode & DMODE_SOFT_SNDFX))
			md_softchn=md_sfxchn;
		else
			md_softchn=0;

		if (!(md_mode & DMODE_SOFT_MUSIC))
			md_softchn+=md_sngchn;
	}
	md_numchn=md_hardchn+md_softchn;
}

/* Note: 'type' indicates whether the returned value should be for music or for
   sound effects. */
ULONG MD_SampleSpace(int type)
{
	if(type==MD_MUSIC)
		type=(md_mode & DMODE_SOFT_MUSIC)?MD_SOFTWARE:MD_HARDWARE;
	else if(type==MD_SNDFX)
		type=(md_mode & DMODE_SOFT_SNDFX)?MD_SOFTWARE:MD_HARDWARE;

	return md_driver->FreeSampleSpace(type);
}

ULONG MD_SampleLength(int type,SAMPLE* s)
{
	if(type==MD_MUSIC)
		type=(md_mode & DMODE_SOFT_MUSIC)?MD_SOFTWARE:MD_HARDWARE;
	else
	  if(type==MD_SNDFX)
		type=(md_mode & DMODE_SOFT_SNDFX)?MD_SOFTWARE:MD_HARDWARE;

	return md_driver->RealSampleLength(type,s);
}

CHAR* MikMod_InfoDriver(void)
{
	int t,len=0;
	MDRIVER *l;
	CHAR *list=NULL;

	MUTEX_LOCK(lists);
	/* compute size of buffer */
	for(l=firstdriver;l;l=l->next)
		if(l->Version)
			len+=4+(l->next?1:0)+strlen(l->Version);

	if(len)
		if((list=_mm_malloc(len*sizeof(CHAR)))) {
			list[0]=0;
			/* list all registered device drivers : */
			for(t=1,l=firstdriver;l;l=l->next,t++)
				if(l->Version)
					sprintf(list,(l->next)?"%s%2d %s\n":"%s%2d %s",
					    list,t,l->Version);
		}
	MUTEX_UNLOCK(lists);
	return list;
}

void _mm_registerdriver(struct MDRIVER* drv)
{
	MDRIVER *cruise = firstdriver;

	if(cruise) {
		while(cruise->next) cruise=cruise->next;
		cruise->next=drv;
	} else
		firstdriver = drv;
}

void _mm_unregisterdrivers(void)
{
	MDRIVER *cruise=firstdriver, *drv;

    while ( cruise ) {
        drv = cruise;
        cruise = cruise->next;
        drv->next = NULL;
    }
    firstdriver = NULL;
}

void MikMod_RegisterDriver(struct MDRIVER* drv)
{
	/* if we try to register an invalid driver, or an already registered driver,
	   ignore this attempt */
	if ((!drv)||(drv->next))
		return;

	MUTEX_LOCK(lists);
	_mm_registerdriver(drv);
	MUTEX_UNLOCK(lists);
}

int MikMod_DriverFromAlias(CHAR *alias)
{
	int rank=1;
	MDRIVER *cruise;

	MUTEX_LOCK(lists);
	cruise=firstdriver;
	while(cruise) {
		if (cruise->Alias) {
			if (!(strcasecmp(alias,cruise->Alias))) break;
			rank++;
		}
		cruise=cruise->next;
	}
	if(!cruise) rank=0;
	MUTEX_UNLOCK(lists);

	return rank;
}

SWORD MD_SampleLoad(SAMPLOAD* s, int type)
{
	SWORD result;

	if(type==MD_MUSIC)
		type=(md_mode & DMODE_SOFT_MUSIC)?MD_SOFTWARE:MD_HARDWARE;
	else if(type==MD_SNDFX)
		type=(md_mode & DMODE_SOFT_SNDFX)?MD_SOFTWARE:MD_HARDWARE;

	SL_Init(s);
	result=md_driver->SampleLoad(s,type);
	SL_Exit(s);

	return result;
}

void MD_SampleUnload(SWORD handle)
{
	md_driver->SampleUnload(handle);
}

MikMod_player_t MikMod_RegisterPlayer(MikMod_player_t player)
{
	MikMod_player_t result;

	MUTEX_LOCK(vars);
	result=md_player;
	md_player=player;
	MUTEX_UNLOCK(vars);

	return result;
}

void MikMod_Update(void)
{
	MUTEX_LOCK(vars);
	if(isplaying) {
		if((!pf)||(!pf->forbid))
			md_driver->Update();
		else {
			if (md_driver->Pause)
				md_driver->Pause();
		}
	}
	MUTEX_UNLOCK(vars);
}

void Voice_SetVolume_internal(SBYTE voice,UWORD vol)
{
	ULONG  tmp;

	if((voice<0)||(voice>=md_numchn)) return;

	/* range checks */
	if(md_musicvolume>128) md_musicvolume=128;
	if(md_sndfxvolume>128) md_sndfxvolume=128;
	if(md_volume>128) md_volume=128;

	tmp=(ULONG)vol*(ULONG)md_volume*
	     ((voice<md_sngchn)?(ULONG)md_musicvolume:(ULONG)md_sndfxvolume);
	md_driver->VoiceSetVolume(voice,tmp/16384UL);
}

void Voice_SetVolume(SBYTE voice,UWORD vol)
{
	MUTEX_LOCK(vars);
	Voice_SetVolume_internal(voice,vol);
	MUTEX_UNLOCK(vars);
}

UWORD Voice_GetVolume(SBYTE voice)
{
	UWORD result=0;

	MUTEX_LOCK(vars);
	if((voice>=0)&&(voice<md_numchn))
		result=md_driver->VoiceGetVolume(voice);
	MUTEX_UNLOCK(vars);

	return result;
}

void Voice_SetFrequency_internal(SBYTE voice,ULONG frq)
{
	if((voice<0)||(voice>=md_numchn)) return;
	if((md_sample[voice])&&(md_sample[voice]->divfactor))
		frq/=md_sample[voice]->divfactor;
	md_driver->VoiceSetFrequency(voice,frq);
}

void Voice_SetFrequency(SBYTE voice,ULONG frq)
{
	MUTEX_LOCK(vars);
	Voice_SetFrequency_internal(voice,frq);
	MUTEX_UNLOCK(vars);
}

ULONG Voice_GetFrequency(SBYTE voice)
{
	ULONG result=0;

	MUTEX_LOCK(vars);
	if((voice>=0)&&(voice<md_numchn))
		result=md_driver->VoiceGetFrequency(voice);
	MUTEX_UNLOCK(vars);

	return result;
}

void Voice_SetPanning_internal(SBYTE voice,ULONG pan)
{
	if((voice<0)||(voice>=md_numchn)) return;
	if(pan!=PAN_SURROUND) {
		if(md_pansep>128) md_pansep=128;
		if(md_mode & DMODE_REVERSE) pan=255-pan;
		pan = (((SWORD)(pan-128)*md_pansep)/128)+128;
	}
	md_driver->VoiceSetPanning(voice, pan);
}

void Voice_SetPanning(SBYTE voice,ULONG pan)
{
#ifdef MIKMOD_DEBUG
	if((pan!=PAN_SURROUND)&&((pan<0)||(pan>255)))
		fprintf(stderr,"\rVoice_SetPanning called with pan=%ld\n",(long)pan);
#endif

	MUTEX_LOCK(vars);
	Voice_SetPanning_internal(voice,pan);
	MUTEX_UNLOCK(vars);
}

ULONG Voice_GetPanning(SBYTE voice)
{
	ULONG result=PAN_CENTER;

	MUTEX_LOCK(vars);
	if((voice>=0)&&(voice<md_numchn))
		result=md_driver->VoiceGetPanning(voice);
	MUTEX_UNLOCK(vars);

	return result;
}

void Voice_Play_internal(SBYTE voice,SAMPLE* s,ULONG start)
{
	ULONG  repend;

	if((voice<0)||(voice>=md_numchn)) return;

	md_sample[voice]=s;
	repend=s->loopend;

	if(s->flags&SF_LOOP)
		/* repend can't be bigger than size */
		if(repend>s->length) repend=s->length;

	md_driver->VoicePlay(voice,s->handle,start,s->length,s->loopstart,repend,s->flags);
}

void Voice_Play(SBYTE voice,SAMPLE* s,ULONG start)
{
	if(start>s->length) return;

	MUTEX_LOCK(vars);
	Voice_Play_internal(voice,s,start);
	MUTEX_UNLOCK(vars);
}

void Voice_Stop_internal(SBYTE voice)
{
	if((voice<0)||(voice>=md_numchn)) return;
	if(voice>=md_sngchn)
		/* It is a sound effects channel, so flag the voice as non-critical! */
		sfxinfo[voice-md_sngchn]=0;
	md_driver->VoiceStop(voice);
}

void Voice_Stop(SBYTE voice)
{
	MUTEX_LOCK(vars);
	Voice_Stop_internal(voice);
	MUTEX_UNLOCK(vars);
}

BOOL Voice_Stopped_internal(SBYTE voice)
{
	if((voice<0)||(voice>=md_numchn)) return 0;
	return(md_driver->VoiceStopped(voice));
}

BOOL Voice_Stopped(SBYTE voice)
{
	BOOL result;

	MUTEX_LOCK(vars);
	result=Voice_Stopped_internal(voice);
	MUTEX_UNLOCK(vars);

	return result;
}

SLONG Voice_GetPosition(SBYTE voice)
{
	SLONG result=0;

	MUTEX_LOCK(vars);
	if((voice>=0)&&(voice<md_numchn))
		result=(md_driver->VoiceGetPosition(voice));
	MUTEX_UNLOCK(vars);

	return result;
}

ULONG Voice_RealVolume(SBYTE voice)
{
	ULONG result=0;