s_sound.c

doom游戏

		|| channels[i].sfxinfo == &S_sfx[sfx_sawhit]) n++;
	}
	    
	if (n>1)
	{
	    for (i=0; i<numChannels ; i++)
	    {
		if (channels[i].sfxinfo == &S_sfx[sfx_sawidl]
		    || channels[i].sfxinfo == &S_sfx[sfx_sawful]
		    || channels[i].sfxinfo == &S_sfx[sfx_sawhit])
		{
		    fprintf(stderr,
			    "chn: sfxinfo=0x%lx, origin=0x%lx, "
			    "handle=%d\n",
			    channels[i].sfxinfo,
			    channels[i].origin,
			    channels[i].handle);
		}
	    }
	    fprintf(stderr, "\n");
	}
    }
}
#endif
 
}




void S_StopSound(void *origin)
{

    int cnum;

    for (cnum=0 ; cnum<numChannels ; cnum++)
    {
	if (channels[cnum].sfxinfo && channels[cnum].origin == origin)
	{
	    S_StopChannel(cnum);
	    break;
	}
    }
}









//
// Stop and resume music, during game PAUSE.
//
void S_PauseSound(void)
{
    if (mus_playing && !mus_paused)
    {
	I_PauseSong(mus_playing->handle);
	mus_paused = true;
    }
}

void S_ResumeSound(void)
{
    if (mus_playing && mus_paused)
    {
	I_ResumeSong(mus_playing->handle);
	mus_paused = false;
    }
}


//
// Updates music & sounds
//
void S_UpdateSounds(void* listener_p)
{
    int		audible;
    int		cnum;
    int		volume;
    int		sep;
    int		pitch;
    sfxinfo_t*	sfx;
    channel_t*	c;
    
    mobj_t*	listener = (mobj_t*)listener_p;


    
    // Clean up unused data.
    // This is currently not done for 16bit (sounds cached static).
    // DOS 8bit remains. 
    /*if (gametic > nextcleanup)
    {
	for (i=1 ; i<NUMSFX ; i++)
	{
	    if (S_sfx[i].usefulness < 1
		&& S_sfx[i].usefulness > -1)
	    {
		if (--S_sfx[i].usefulness == -1)
		{
		    Z_ChangeTag(S_sfx[i].data, PU_CACHE);
		    S_sfx[i].data = 0;
		}
	    }
	}
	nextcleanup = gametic + 15;
    }*/
    
    for (cnum=0 ; cnum<numChannels ; cnum++)
    {
	c = &channels[cnum];
	sfx = c->sfxinfo;

	if (c->sfxinfo)
	{
	    if (I_SoundIsPlaying(c->handle))
	    {
		// initialize parameters
		volume = snd_SfxVolume;
		pitch = NORM_PITCH;
		sep = NORM_SEP;

		if (sfx->link)
		{
		    pitch = sfx->pitch;
		    volume += sfx->volume;
		    if (volume < 1)
		    {
			S_StopChannel(cnum);
			continue;
		    }
		    else if (volume > snd_SfxVolume)
		    {
			volume = snd_SfxVolume;
		    }
		}

		// check non-local sounds for distance clipping
		//  or modify their params
		if (c->origin && listener_p != c->origin)
		{
		    audible = S_AdjustSoundParams(listener,
						  c->origin,
						  &volume,
						  &sep,
						  &pitch);
		    
		    if (!audible)
		    {
			S_StopChannel(cnum);
		    }
		    else
			I_UpdateSoundParams(c->handle, volume, sep, pitch);
		}
	    }
	    else
	    {
		// if channel is allocated but sound has stopped,
		//  free it
		S_StopChannel(cnum);
	    }
	}
    }
    // kill music if it is a single-play && finished
    // if (	mus_playing
    //      && !I_QrySongPlaying(mus_playing->handle)
    //      && !mus_paused )
    // S_StopMusic();
}


void S_SetMusicVolume(int volume)
{
    if (volume < 0 || volume > 127)
    {
	I_Error("Attempt to set music volume at %d",
		volume);
    }    

    I_SetMusicVolume(127);
    I_SetMusicVolume(volume);
    snd_MusicVolume = volume;
}



void S_SetSfxVolume(int volume)
{

    if (volume < 0 || volume > 127)
	I_Error("Attempt to set sfx volume at %d", volume);

    snd_SfxVolume = volume;

}

//
// Starts some music with the music id found in sounds.h.
//
void S_StartMusic(int m_id)
{
    S_ChangeMusic(m_id, false);
}

void
S_ChangeMusic
( int			musicnum,
  int			looping )
{
    musicinfo_t*	music;
    char		namebuf[9];

    if ( (musicnum <= mus_None)
	 || (musicnum >= NUMMUSIC) )
    {
	I_Error("Bad music number %d", musicnum);
    }
    else
	music = &S_music[musicnum];

    if (mus_playing == music)
	return;

    // shutdown old music
    S_StopMusic();

    // get lumpnum if neccessary
    if (!music->lumpnum)
    {
	sprintf(namebuf, "d_%s", music->name);
	music->lumpnum = W_GetNumForName(namebuf);
    }

    // load & register it
    music->data = (void *) W_CacheLumpNum(music->lumpnum, PU_MUSIC);
    music->handle = I_RegisterSong(music->data);

    // play it
    I_PlaySong(music->handle, looping);

    mus_playing = music;
}


void S_StopMusic(void)
{
    if (mus_playing)
    {
	if (mus_paused)
	    I_ResumeSong(mus_playing->handle);

	I_StopSong(mus_playing->handle);
	I_UnRegisterSong(mus_playing->handle);
	Z_ChangeTag(mus_playing->data, PU_CACHE);
	
	mus_playing->data = 0;
	mus_playing = 0;
    }
}




void S_StopChannel(int cnum)
{

    int		i;
    channel_t*	c = &channels[cnum];

    if (c->sfxinfo)
    {
	// stop the sound playing
	if (I_SoundIsPlaying(c->handle))
	{
#ifdef SAWDEBUG
	    if (c->sfxinfo == &S_sfx[sfx_sawful])
		fprintf(stderr, "stopped\n");
#endif
	    I_StopSound(c->handle);
	}

	// check to see
	//  if other channels are playing the sound
	for (i=0 ; i<numChannels ; i++)
	{
	    if (cnum != i
		&& c->sfxinfo == channels[i].sfxinfo)
	    {
		break;
	    }
	}
	
	// degrade usefulness of sound data
	c->sfxinfo->usefulness--;

	c->sfxinfo = 0;
    }
}



//
// Changes volume, stereo-separation, and pitch variables
//  from the norm of a sound effect to be played.
// If the sound is not audible, returns a 0.
// Otherwise, modifies parameters and returns 1.
//
int
S_AdjustSoundParams
( mobj_t*	listener,
  mobj_t*	source,
  int*		vol,
  int*		sep,
  int*		pitch )
{
    fixed_t	approx_dist;
    fixed_t	adx;
    fixed_t	ady;
    angle_t	angle;

    // calculate the distance to sound origin
    //  and clip it if necessary
    adx = abs(listener->x - source->x);
    ady = abs(listener->y - source->y);

    // From _GG1_ p.428. Appox. eucledian distance fast.
    approx_dist = adx + ady - ((adx < ady ? adx : ady)>>1);
    
    if (gamemap != 8
	&& approx_dist > S_CLIPPING_DIST)
    {
	return 0;
    }
    
    // angle of source to listener
    angle = R_PointToAngle2(listener->x,
			    listener->y,
			    source->x,
			    source->y);

    if (angle > listener->angle)
	angle = angle - listener->angle;
    else
	angle = angle + (0xffffffff - listener->angle);

    angle >>= ANGLETOFINESHIFT;

    // stereo separation
    *sep = 128 - (FixedMul(S_STEREO_SWING,finesine[angle])>>FRACBITS);

    // volume calculation
    if (approx_dist < S_CLOSE_DIST)
    {
	*vol = snd_SfxVolume;
    }
    else if (gamemap == 8)
    {
	if (approx_dist > S_CLIPPING_DIST)
	    approx_dist = S_CLIPPING_DIST;

	*vol = 15+ ((snd_SfxVolume-15)
		    *((S_CLIPPING_DIST - approx_dist)>>FRACBITS))
	    / S_ATTENUATOR;
    }
    else
    {
	// distance effect
	*vol = (snd_SfxVolume
		* ((S_CLIPPING_DIST - approx_dist)>>FRACBITS))
	    / S_ATTENUATOR; 
    }
    
    return (*vol > 0);
}




//
// S_getChannel :
//   If none available, return -1.  Otherwise channel #.
//
int
S_getChannel
( void*		origin,
  sfxinfo_t*	sfxinfo )
{
    // channel number to use
    int		cnum;
    
    channel_t*	c;

    // Find an open channel
    for (cnum=0 ; cnum<numChannels ; cnum++)
    {
	if (!channels[cnum].sfxinfo)
	    break;
	else if (origin &&  channels[cnum].origin ==  origin)
	{
	    S_StopChannel(cnum);
	    break;
	}
    }

    // None available
    if (cnum == numChannels)
    {
	// Look for lower priority
	for (cnum=0 ; cnum<numChannels ; cnum++)
	    if (channels[cnum].sfxinfo->priority >= sfxinfo->priority) break;

	if (cnum == numChannels)
	{
	    // FUCK!  No lower priority.  Sorry, Charlie.    
	    return -1;
	}
	else
	{
	    // Otherwise, kick out lower priority.
	    S_StopChannel(cnum);
	}
    }

    c = &channels[cnum];

    // channel is decided to be cnum.
    c->sfxinfo = sfxinfo;
    c->origin = origin;

    return cnum;
}