main.c

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/*
Copyright (C) 1997-2001 Id Software, Inc.
 
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.
*/
// snd_main.c -- common sound functions
 
#include "sound.h"
#include "client/sound/vorbis.h"
 
// =======================================================================
// Internal sound data & structures
// =======================================================================
 
int         s_registration_sequence;
 
channel_t   channels[MAX_CHANNELS];
int         s_numchannels;
 
sndstarted_t s_started;
qboolean    s_active;
 
vec3_t      listener_origin;
vec3_t      listener_forward;
vec3_t      listener_right;
vec3_t      listener_up;
int         listener_entnum;
 
qboolean    s_registering;
 
int         paintedtime;    // sample PAIRS
 
// during registration it is possible to have more sounds
// than could actually be referenced during gameplay,
// because we don't want to free anything until we are
// sure we won't need it.
#define     MAX_SFX     (MAX_SOUNDS*2)
static sfx_t        known_sfx[MAX_SFX];
static int          num_sfx;
 
#define     MAX_PLAYSOUNDS  128
playsound_t s_playsounds[MAX_PLAYSOUNDS];
playsound_t s_freeplays;
playsound_t s_pendingplays;
 
cvar_t      *s_volume;
cvar_t      *s_ambient;
#ifdef _DEBUG
cvar_t      *s_show;
#endif
 
static cvar_t   *s_enable;
static cvar_t   *s_auto_focus;
static cvar_t   *s_swapstereo;
 
// =======================================================================
// Console functions
// =======================================================================
 
static void S_SoundInfo_f(void)
{
    if (!s_started) {
        Com_Printf("Sound system not started.\n");
        return;
    }
 
#if USE_OPENAL
    if (s_started == SS_OAL)
        AL_SoundInfo();
#endif
 
#if USE_SNDDMA
    if (s_started == SS_DMA)
        DMA_SoundInfo();
#endif
}
 
static void S_SoundList_f(void)
{
    int     i;
    sfx_t   *sfx;
    sfxcache_t  *sc;
    int     size, total;
 
    total = 0;
    for (sfx = known_sfx, i = 0; i < num_sfx; i++, sfx++) {
        if (!sfx->name[0])
            continue;
        sc = sfx->cache;
        if (sc) {
#if USE_OPENAL
            if (s_started == SS_OAL)
                size = sc->size;
            else
#endif
                size = sc->length * sc->width;
            total += size;
            if (sc->loopstart >= 0)
                Com_Printf("L");
            else
                Com_Printf(" ");
            Com_Printf("(%2db) %6i : %s\n", sc->width * 8,  size, sfx->name) ;
        } else {
            if (sfx->name[0] == '*')
                Com_Printf("  placeholder : %s\n", sfx->name);
            else
                Com_Printf("  not loaded  : %s (%s)\n",
                           sfx->name, Q_ErrorString(sfx->error));
        }
    }
    Com_Printf("Total resident: %i\n", total);
}
 
static const cmdreg_t c_sound[] = {
    { "stopsound", S_StopAllSounds },
    { "soundlist", S_SoundList_f },
    { "soundinfo", S_SoundInfo_f },
 
    { NULL }
};
 
// =======================================================================
// Init sound engine
// =======================================================================
 
static void s_auto_focus_changed(cvar_t *self)
{
    S_Activate();
}
 
/*
================
S_Init
================
*/
void S_Init(void)
{
    s_enable = Cvar_Get("s_enable", "2", CVAR_SOUND);
    if (s_enable->integer <= SS_NOT) {
        Com_Printf("Sound initialization disabled.\n");
        return;
    }
 
    Com_Printf("------- S_Init -------\n");
 
    s_volume = Cvar_Get("s_volume", "0.7", CVAR_ARCHIVE);
    s_ambient = Cvar_Get("s_ambient", "1", 0);
#ifdef _DEBUG
    s_show = Cvar_Get("s_show", "0", 0);
#endif
    s_auto_focus = Cvar_Get("s_auto_focus", "0", 0);
    s_swapstereo = Cvar_Get("s_swapstereo", "0", 0);
 
    // start one of available sound engines
    s_started = SS_NOT;
 
#if USE_OPENAL
    if (s_started == SS_NOT && s_enable->integer >= SS_OAL && AL_Init())
        s_started = SS_OAL;
#endif
 
#if USE_SNDDMA
    if (s_started == SS_NOT && s_enable->integer >= SS_DMA && DMA_Init())
        s_started = SS_DMA;
#endif
 
    if (s_started == SS_NOT) {
        Com_EPrintf("Sound failed to initialize.\n");
        goto fail;
    }
 
    Cmd_Register(c_sound);
 
    // init playsound list
    // clear DMA buffer
    S_StopAllSounds();
 
    s_auto_focus->changed = s_auto_focus_changed;
    s_auto_focus_changed(s_auto_focus);
 
    num_sfx = 0;
 
    paintedtime = 0;
 
    s_registration_sequence = 1;
    
    OGG_Init();
    OGG_InitTrackList();
    OGG_RecoverState();
 
fail:
    Cvar_SetInteger(s_enable, s_started, FROM_CODE);
    Com_Printf("----------------------\n");
}
 
 
// =======================================================================
// Shutdown sound engine
// =======================================================================
 
static void S_FreeSound(sfx_t *sfx)
{
#if USE_OPENAL
    if (s_started == SS_OAL)
        AL_DeleteSfx(sfx);
#endif
    if (sfx->cache)
        Z_Free(sfx->cache);
    if (sfx->truename)
        Z_Free(sfx->truename);
    memset(sfx, 0, sizeof(*sfx));
}
 
void S_FreeAllSounds(void)
{
    int     i;
    sfx_t   *sfx;
 
    // free all sounds
    for (i = 0, sfx = known_sfx; i < num_sfx; i++, sfx++) {
        if (!sfx->name[0])
            continue;
        S_FreeSound(sfx);
    }
 
    num_sfx = 0;
}
 
void S_Shutdown(void)
{
    if (!s_started)
        return;
 
    S_StopAllSounds();
    S_FreeAllSounds();
 
    OGG_SaveState();
    OGG_Shutdown();
 
#if USE_OPENAL
    if (s_started == SS_OAL)
        AL_Shutdown();
#endif
 
#if USE_SNDDMA
    if (s_started == SS_DMA)
        DMA_Shutdown();
#endif
 
    s_started = SS_NOT;
    s_active = qfalse;
 
    s_auto_focus->changed = NULL;
 
    Cmd_Deregister(c_sound);
 
    Z_LeakTest(TAG_SOUND);
}
 
void S_Activate(void)
{
    qboolean active;
    active_t level;
 
    if (!s_started)
        return;
 
    level = Cvar_ClampInteger(s_auto_focus, ACT_MINIMIZED, ACT_ACTIVATED);
 
    active = cls.active >= level;
 
    if (active == s_active)
        return;
 
    s_active = active;
 
    Com_DDDPrintf("%s: %d\n", __func__, s_active);
 
#if USE_OPENAL
    if (s_started == SS_OAL)
        S_StopAllSounds();
#endif
 
#if USE_SNDDMA
    if (s_started == SS_DMA)
        DMA_Activate();
#endif
}
 
 
// =======================================================================
// Load a sound
// =======================================================================
 
/*
==================
S_SfxForHandle
==================
*/
sfx_t *S_SfxForHandle(qhandle_t hSfx)
{
    if (!hSfx) {
        return NULL;
    }
 
    if (hSfx < 1 || hSfx > num_sfx) {
        Com_Error(ERR_DROP, "S_SfxForHandle: %d out of range", hSfx);
    }
 
    return &known_sfx[hSfx - 1];
}
 
static sfx_t *S_AllocSfx(void)
{
    sfx_t   *sfx;
    int     i;
 
    // find a free sfx
    for (i = 0, sfx = known_sfx; i < num_sfx; i++, sfx++) {
        if (!sfx->name[0])
            break;
    }
 
    if (i == num_sfx) {
        if (num_sfx == MAX_SFX)
            return NULL;
        num_sfx++;
    }
 
    return sfx;
}
 
/*
==================
S_FindName
 
==================
*/
static sfx_t *S_FindName(const char *name, size_t namelen)
{
    int     i;
    sfx_t   *sfx;
 
    // see if already loaded
    for (i = 0, sfx = known_sfx; i < num_sfx; i++, sfx++) {
        if (!FS_pathcmp(sfx->name, name)) {
            sfx->registration_sequence = s_registration_sequence;
            return sfx;
        }
    }
 
    // allocate new one
    sfx = S_AllocSfx();
    if (sfx) {
        memcpy(sfx->name, name, namelen + 1);
        sfx->registration_sequence = s_registration_sequence;
    }
    return sfx;
}
 
/*
=====================
S_BeginRegistration
 
=====================
*/
void S_BeginRegistration(void)
{
    s_registration_sequence++;
    s_registering = qtrue;
}
 
/*
==================
S_RegisterSound
 
==================
*/
qhandle_t S_RegisterSound(const char *name)
{
    char    buffer[MAX_QPATH];
    sfx_t   *sfx;
    size_t  len;
 
    if (!s_started)
        return 0;
 
    // empty names are legal, silently ignore them
    if (!*name)
        return 0;
 
    if (*name == '*') {
        len = Q_strlcpy(buffer, name, MAX_QPATH);
    } else if (*name == '#') {
        len = FS_NormalizePathBuffer(buffer, name + 1, MAX_QPATH);
    } else {
        len = Q_concat(buffer, MAX_QPATH, "sound/", name, NULL);
        if (len < MAX_QPATH)
            len = FS_NormalizePath(buffer, buffer);
    }
 
    // this MAY happen after prepending "sound/"
    if (len >= MAX_QPATH) {
        Com_DPrintf("%s: oversize name\n", __func__);
        return 0;
    }
 
    // normalized to empty name?
    if (len == 0) {
        Com_DPrintf("%s: empty name\n", __func__);
        return 0;
    }
 
    sfx = S_FindName(buffer, len);
    if (!sfx) {
        Com_DPrintf("%s: out of slots\n", __func__);
        return 0;
    }
 
    if (!s_registering) {
        S_LoadSound(sfx);
    }
 
    return (sfx - known_sfx) + 1;
}
 
/*
====================
S_RegisterSexedSound
====================
*/
static sfx_t *S_RegisterSexedSound(int entnum, const char *base)
{
    sfx_t           *sfx;
    char            *model;
    char            buffer[MAX_QPATH];
    size_t          len;
 
    // determine what model the client is using
    if (entnum > 0 && entnum <= MAX_CLIENTS)
        model = cl.clientinfo[entnum - 1].model_name;
    else
        model = cl.baseclientinfo.model_name;
 
    // if we can't figure it out, they're male
    if (!*model)
        model = "male";
 
    // see if we already know of the model specific sound
    len = Q_concat(buffer, MAX_QPATH,
                   "players/", model, "/", base + 1, NULL);
    if (len >= MAX_QPATH) {
        len = Q_concat(buffer, MAX_QPATH,
                       "players/", "male", "/", base + 1, NULL);
        if (len >= MAX_QPATH)
            return NULL;
    }
 
    len = FS_NormalizePath(buffer, buffer);
    sfx = S_FindName(buffer, len);
 
    // see if it exists
    if (sfx && !sfx->truename && !s_registering && !S_LoadSound(sfx)) {
        // no, revert to the male sound in the pak0.pak
        len = Q_concat(buffer, MAX_QPATH,
                       "sound/player/male/", base + 1, NULL);
        if (len < MAX_QPATH) {
            FS_NormalizePath(buffer, buffer);
            sfx->error = Q_ERR_SUCCESS;
            sfx->truename = S_CopyString(buffer);
        }
    }
 
    return sfx;
}
 
static void S_RegisterSexedSounds(void)
{
    int     sounds[MAX_SFX];
    int     i, j, total;
    sfx_t   *sfx;
 
    // find sexed sounds
    total = 0;
    for (i = 0, sfx = known_sfx; i < num_sfx; i++, sfx++) {
        if (sfx->name[0] != '*')
            continue;
        if (sfx->registration_sequence != s_registration_sequence)
            continue;
        sounds[total++] = i;
    }
 
    // register sounds for baseclientinfo and other valid clientinfos
    for (i = 0; i <= MAX_CLIENTS; i++) {
        if (i > 0 && !cl.clientinfo[i - 1].model_name[0])
            continue;
        for (j = 0; j < total; j++) {
            sfx = &known_sfx[sounds[j]];
            S_RegisterSexedSound(i, sfx->name);
        }
    }
}
 
/*
=====================
S_EndRegistration
 
=====================
*/
void S_EndRegistration(void)
{
    int     i;
    sfx_t   *sfx;
#if USE_SNDDMA
    sfxcache_t *sc;
    int     size;
#endif
 
    S_RegisterSexedSounds();
 
    // clear playsound list, so we don't free sfx still present there
    S_StopAllSounds();
 
    // free any sounds not from this registration sequence
    for (i = 0, sfx = known_sfx; i < num_sfx; i++, sfx++) {
        if (!sfx->name[0])
            continue;
        if (sfx->registration_sequence != s_registration_sequence) {
            // don't need this sound
            S_FreeSound(sfx);
            continue;
        }
#if USE_OPENAL
        if (s_started == SS_OAL)
            continue;
#endif
#if USE_SNDDMA
        // make sure it is paged in
        sc = sfx->cache;
        if (sc) {
            size = sc->length * sc->width;
            Com_PageInMemory(sc, size);
        }
#endif
    }
 
    // load everything in
    for (i = 0, sfx = known_sfx; i < num_sfx; i++, sfx++) {
        if (!sfx->name[0])
            continue;
        S_LoadSound(sfx);
    }
 
    s_registering = qfalse;
}
 
 
//=============================================================================
 
/*
=================
S_PickChannel
 
picks a channel based on priorities, empty slots, number of channels
=================
*/
channel_t *S_PickChannel(int entnum, int entchannel)
{
    int         ch_idx;
    int         first_to_die;
    int         life_left;
    channel_t   *ch;
 
    if (entchannel < 0)
        Com_Error(ERR_DROP, "S_PickChannel: entchannel < 0");
 
// Check for replacement sound, or find the best one to replace
    first_to_die = -1;
    life_left = 0x7fffffff;
    for (ch_idx = 0; ch_idx < s_numchannels; ch_idx++) {
        ch = &channels[ch_idx];
        // channel 0 never overrides unless out of channels
        if (ch->entnum == entnum && ch->entchannel == entchannel && entchannel != 0) {
            if (entchannel == 256 && ch->sfx) {
                return NULL; // channel 256 never overrides
            }
            // always override sound from same entity
            first_to_die = ch_idx;
            break;
        }
 
        // don't let monster sounds override player sounds
        if (ch->entnum == listener_entnum && entnum != listener_entnum && ch->sfx)
            continue;
 
        if (ch->end - paintedtime < life_left) {
            life_left = ch->end - paintedtime;
            first_to_die = ch_idx;
        }
    }
 
    if (first_to_die == -1)
        return NULL;
 
    ch = &channels[first_to_die];
#if USE_OPENAL
    if (s_started == SS_OAL && ch->sfx)
        AL_StopChannel(ch);
#endif
    memset(ch, 0, sizeof(*ch));
 
    return ch;
}
 
#if USE_SNDDMA
 
/*
=================
S_SpatializeOrigin
 
Used for spatializing channels and autosounds
=================
*/
void S_SpatializeOrigin(const vec3_t origin, float master_vol, float dist_mult, int *left_vol, int *right_vol)
{
    vec_t       dot;
    vec_t       dist;
    vec_t       lscale, rscale, scale;
    vec3_t      source_vec;
 
    if (cls.state != ca_active) {
        *left_vol = *right_vol = 255;
        return;
    }
 
// calculate stereo seperation and distance attenuation
    VectorSubtract(origin, listener_origin, source_vec);
 
    dist = VectorNormalize(source_vec);
    dist -= SOUND_FULLVOLUME;
    if (dist < 0)
        dist = 0;           // close enough to be at full volume
    dist *= dist_mult;      // different attenuation levels
 
    dot = DotProduct(listener_right, source_vec);
    if (s_swapstereo->integer)
        dot = -dot;
 
    if (dma.channels == 1 || !dist_mult) {
        // no attenuation = no spatialization
        rscale = 1.0;
        lscale = 1.0;
    } else {
        rscale = 0.5 * (1.0 + dot);
        lscale = 0.5 * (1.0 - dot);
    }
 
    master_vol *= 255.0;
 
    // add in distance effect
    scale = (1.0 - dist) * rscale;
    *right_vol = (int)(master_vol * scale);
    if (*right_vol < 0)
        *right_vol = 0;
 
    scale = (1.0 - dist) * lscale;
    *left_vol = (int)(master_vol * scale);
    if (*left_vol < 0)
        *left_vol = 0;
}
 
/*
=================
S_Spatialize
=================
*/
static void S_Spatialize(channel_t *ch)
{
    vec3_t      origin;
 
    // anything coming from the view entity will always be full volume
    if (ch->entnum == -1 || ch->entnum == listener_entnum) {
        ch->leftvol = ch->master_vol * 255;
        ch->rightvol = ch->master_vol * 255;
        return;
    }
 
    if (ch->fixed_origin) {
        VectorCopy(ch->origin, origin);
    } else {
        CL_GetEntitySoundOrigin(ch->entnum, origin);
    }
 
    S_SpatializeOrigin(origin, ch->master_vol, ch->dist_mult, &ch->leftvol, &ch->rightvol);
}
 
#endif
 
/*
=================
S_AllocPlaysound
=================
*/
static playsound_t *S_AllocPlaysound(void)
{
    playsound_t *ps;
 
    ps = s_freeplays.next;
    if (ps == &s_freeplays)
        return NULL;        // no free playsounds
 
    // unlink from freelist
    ps->prev->next = ps->next;
    ps->next->prev = ps->prev;
 
    return ps;
}
 
 
/*
=================
S_FreePlaysound
=================
*/
static void S_FreePlaysound(playsound_t *ps)
{
    // unlink from channel
    ps->prev->next = ps->next;
    ps->next->prev = ps->prev;
 
    // add to free list
    ps->next = s_freeplays.next;
    s_freeplays.next->prev = ps;
    ps->prev = &s_freeplays;
    s_freeplays.next = ps;
}
 
/*
===============
S_IssuePlaysound
 
Take the next playsound and begin it on the channel
This is never called directly by S_Play*, but only
by the update loop.
===============
*/
void S_IssuePlaysound(playsound_t *ps)
{
    channel_t   *ch;
    sfxcache_t  *sc;
 
#ifdef _DEBUG
    if (s_show->integer)
        Com_Printf("Issue %i\n", ps->begin);
#endif
    // pick a channel to play on
    ch = S_PickChannel(ps->entnum, ps->entchannel);
    if (!ch) {
        S_FreePlaysound(ps);
        return;
    }
 
    sc = S_LoadSound(ps->sfx);
    if (!sc) {
        Com_Printf("S_IssuePlaysound: couldn't load %s\n", ps->sfx->name);
        S_FreePlaysound(ps);
        return;
    }
 
    // spatialize
    if (ps->attenuation == ATTN_STATIC)
        ch->dist_mult = ps->attenuation * 0.001;
    else
        ch->dist_mult = ps->attenuation * 0.0005;
    ch->master_vol = ps->volume;
    ch->entnum = ps->entnum;
    ch->entchannel = ps->entchannel;
    ch->sfx = ps->sfx;
    VectorCopy(ps->origin, ch->origin);
    ch->fixed_origin = ps->fixed_origin;
 
#if USE_OPENAL
    if (s_started == SS_OAL)
        AL_PlayChannel(ch);
#endif
 
#if USE_SNDDMA
    if (s_started == SS_DMA)
        S_Spatialize(ch);
#endif
 
    ch->pos = 0;
    ch->end = paintedtime + sc->length;
 
    // free the playsound
    S_FreePlaysound(ps);
}
 
// =======================================================================
// Start a sound effect
// =======================================================================
 
/*
====================
S_StartSound
 
Validates the parms and ques the sound up
if pos is NULL, the sound will be dynamically sourced from the entity
Entchannel 0 will never override a playing sound
====================
*/
void S_StartSound(const vec3_t origin, int entnum, int entchannel, qhandle_t hSfx, float vol, float attenuation, float timeofs)
{
    sfxcache_t  *sc;
    playsound_t *ps, *sort;
    sfx_t       *sfx;
 
    if (!s_started)
        return;
    if (!s_active)
        return;
 
    if (!(sfx = S_SfxForHandle(hSfx))) {
        return;
    }
 
    if (sfx->name[0] == '*') {
        sfx = S_RegisterSexedSound(entnum, sfx->name);
        if (!sfx)
            return;
    }
 
    // make sure the sound is loaded
    sc = S_LoadSound(sfx);
    if (!sc)
        return;     // couldn't load the sound's data
 
    // make the playsound_t
    ps = S_AllocPlaysound();
    if (!ps)
        return;
 
    if (origin) {
        VectorCopy(origin, ps->origin);
        ps->fixed_origin = qtrue;
    } else {
        ps->fixed_origin = qfalse;
    }
 
    ps->entnum = entnum;
    ps->entchannel = entchannel;
    ps->attenuation = attenuation;
    ps->volume = vol;
    ps->sfx = sfx;
 
#if USE_OPENAL
    if (s_started == SS_OAL)
        ps->begin = paintedtime + timeofs * 1000;
#endif
 
#if USE_SNDDMA
    if (s_started == SS_DMA)
        ps->begin = DMA_DriftBeginofs(timeofs);
#endif
 
    // sort into the pending sound list
    for (sort = s_pendingplays.next; sort != &s_pendingplays && sort->begin < ps->begin; sort = sort->next)
        ;
 
    ps->next = sort;
    ps->prev = sort->prev;
 
    ps->next->prev = ps;
    ps->prev->next = ps;
}
 
void S_ParseStartSound(void)
{
    qhandle_t handle = cl.sound_precache[snd.index];
 
    if (!handle)
        return;
 
#ifdef _DEBUG
    if (developer->integer && !(snd.flags & SND_POS))
        CL_CheckEntityPresent(snd.entity, "sound");
#endif
 
    S_StartSound((snd.flags & SND_POS) ? snd.pos : NULL,
                 snd.entity, snd.channel, handle,
                 snd.volume, snd.attenuation, snd.timeofs);
}
 
/*
==================
S_StartLocalSound
==================
*/
void S_StartLocalSound(const char *sound)
{
    if (s_started) {
        qhandle_t sfx = S_RegisterSound(sound);
        S_StartSound(NULL, listener_entnum, 0, sfx, 1, ATTN_NONE, 0);
    }
}
 
void S_StartLocalSound_(const char *sound)
{
    if (s_started) {
        qhandle_t sfx = S_RegisterSound(sound);
        S_StartSound(NULL, listener_entnum, 256, sfx, 1, ATTN_NONE, 0);
    }
}
 
/*
==================
S_StopAllSounds
==================
*/
void S_StopAllSounds(void)
{
    int     i;
 
    if (!s_started)
        return;
 
    // clear all the playsounds
    memset(s_playsounds, 0, sizeof(s_playsounds));
    s_freeplays.next = s_freeplays.prev = &s_freeplays;
    s_pendingplays.next = s_pendingplays.prev = &s_pendingplays;
 
    for (i = 0; i < MAX_PLAYSOUNDS; i++) {
        s_playsounds[i].prev = &s_freeplays;
        s_playsounds[i].next = s_freeplays.next;
        s_playsounds[i].prev->next = &s_playsounds[i];
        s_playsounds[i].next->prev = &s_playsounds[i];
    }
 
#if USE_OPENAL
    if (s_started == SS_OAL)
        AL_StopAllChannels();
#endif
 
#if USE_SNDDMA
    if (s_started == SS_DMA)
        DMA_ClearBuffer();
#endif
 
    // clear all the channels
    memset(channels, 0, sizeof(channels));
}
 
// =======================================================================
// Update sound buffer
// =======================================================================
 
void S_BuildSoundList(int *sounds)
{
    int         i;
    int         num;
    entity_state_t  *ent;
 
    for (i = 0; i < cl.frame.numEntities; i++) {
        num = (cl.frame.firstEntity + i) & PARSE_ENTITIES_MASK;
        ent = &cl.entityStates[num];
        if (s_ambient->integer == 2 && !ent->modelindex) {
            sounds[i] = 0;
        } else if (s_ambient->integer == 3 && ent->number != listener_entnum) {
            sounds[i] = 0;
        } else {
            sounds[i] = ent->sound;
        }
    }
}
 
#if USE_SNDDMA
 
/*
==================
S_AddLoopSounds
 
Entities with a ->sound field will generated looped sounds
that are automatically started, stopped, and merged together
as the entities are sent to the client
==================
*/
static void S_AddLoopSounds(void)
{
    int         i, j;
    int         sounds[MAX_EDICTS];
    int         left, right, left_total, right_total;
    channel_t   *ch;
    sfx_t       *sfx;
    sfxcache_t  *sc;
    int         num;
    entity_state_t  *ent;
    vec3_t      origin;
 
    if (cls.state != ca_active || !s_active || sv_paused->integer || !s_ambient->integer) {
        return;
    }
 
    S_BuildSoundList(sounds);
 
    for (i = 0; i < cl.frame.numEntities; i++) {
        if (!sounds[i])
            continue;
 
        sfx = S_SfxForHandle(cl.sound_precache[sounds[i]]);
        if (!sfx)
            continue;       // bad sound effect
        sc = sfx->cache;
        if (!sc)
            continue;
 
        num = (cl.frame.firstEntity + i) & PARSE_ENTITIES_MASK;
        ent = &cl.entityStates[num];
 
        // find the total contribution of all sounds of this type
        CL_GetEntitySoundOrigin(ent->number, origin);
        S_SpatializeOrigin(origin, 1.0, SOUND_LOOPATTENUATE,
                           &left_total, &right_total);
        for (j = i + 1; j < cl.frame.numEntities; j++) {
            if (sounds[j] != sounds[i])
                continue;
            sounds[j] = 0;  // don't check this again later
 
            num = (cl.frame.firstEntity + j) & PARSE_ENTITIES_MASK;
            ent = &cl.entityStates[num];
 
            CL_GetEntitySoundOrigin(ent->number, origin);
            S_SpatializeOrigin(origin, 1.0, SOUND_LOOPATTENUATE,
                               &left, &right);
            left_total += left;
            right_total += right;
        }
 
        if (left_total == 0 && right_total == 0)
            continue;       // not audible
 
        // allocate a channel
        ch = S_PickChannel(0, 0);
        if (!ch)
            return;
 
        if (left_total > 255)
            left_total = 255;
        if (right_total > 255)
            right_total = 255;
        ch->leftvol = left_total;
        ch->rightvol = right_total;
        ch->autosound = qtrue;  // remove next frame
        ch->sfx = sfx;
        ch->pos = paintedtime % sc->length;
        ch->end = paintedtime + sc->length - ch->pos;
    }
}
 
#endif
 
/*
============
S_Update
 
Called once each time through the main loop
============
*/
void S_Update(void)
{
#if USE_SNDDMA
    int         i;
    channel_t   *ch;
#endif
 
    if (cvar_modified & CVAR_SOUND) {
        Cbuf_AddText(&cmd_buffer, "snd_restart\n");
        cvar_modified &= ~CVAR_SOUND;
        return;
    }
 
    if (!s_started)
        return;
 
    // if the laoding plaque is up, clear everything
    // out to make sure we aren't looping a dirty
    // dma buffer while loading
    if (cls.state == ca_loading) {
        // S_ClearBuffer should be already done in S_StopAllSounds
        return;
    }
 
    // set listener entity number
    // other parameters should be already set up by CL_CalcViewValues
    if (cl.clientNum == -1 || cl.frame.clientNum == CLIENTNUM_NONE) {
        listener_entnum = -1;
    } else {
        listener_entnum = cl.frame.clientNum + 1;
    }
 
#if USE_OPENAL
    if (s_started == SS_OAL) {
        OGG_Stream();
        AL_Update();
        return;
    }
#endif
 
#if USE_SNDDMA
    // rebuild scale tables if volume is modified
    if (s_volume->modified)
        S_InitScaletable();
 
    // update spatialization for dynamic sounds
    ch = channels;
    for (i = 0; i < s_numchannels; i++, ch++) {
        if (!ch->sfx)
            continue;
        if (ch->autosound) {
            // autosounds are regenerated fresh each frame
            memset(ch, 0, sizeof(*ch));
            continue;
        }
        S_Spatialize(ch);         // respatialize channel
        if (!ch->leftvol && !ch->rightvol) {
            memset(ch, 0, sizeof(*ch));
            continue;
        }
    }
 
    // add loopsounds
    S_AddLoopSounds();
 
    OGG_Stream();
 
#ifdef _DEBUG
    //
    // debugging output
    //
    if (s_show->integer) {
        int total = 0;
        ch = channels;
        for (i = 0; i < s_numchannels; i++, ch++)
            if (ch->sfx && (ch->leftvol || ch->rightvol)) {
                Com_Printf("%3i %3i %s\n", ch->leftvol, ch->rightvol, ch->sfx->name);
                total++;
            }
 
        if (s_show->integer > 1 || total) {
            Com_Printf("----(%i)---- painted: %i\n", total, paintedtime);
        }
    }
#endif
 
// mix some sound
    DMA_Update();
#endif
}
 
float S_GetLinearVolume(float perceptual)
{
    float volume = perceptual;
    
    // clamp anything below 1% to zero
    if (volume < 0.01f)
        return 0.f;
 
    // 50 dB exponential curve
    // more info: https://www.dr-lex.be/info-stuff/volumecontrols.html 
    volume = 0.003161f * expf(perceptual * 5.757f);
 
    // upper limit
    volume = min(1.f, volume);
 
    return volume;
}