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Thu, May 9, 18:50

source.c
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#ifndef lint
static const char RCSid[] = "$Id: source.c,v 2.77 2021/11/24 19:08:51 greg Exp $";
#endif
/*
* source.c - routines dealing with illumination sources.
*
* External symbols declared in source.h
*/
#include "ray.h"
#include "otypes.h"
#include "otspecial.h"
#include "rtotypes.h"
#include "source.h"
#include "random.h"
#include "pmapsrc.h"
#include "pmapmat.h"
#ifndef MAXSSAMP
#define MAXSSAMP 16 /* maximum samples per ray */
#endif
/*
* Structures used by direct()
*/
typedef struct {
int sno; /* source number */
FVECT dir; /* source direction */
COLOR coef; /* material coefficient */
COLOR val; /* contribution */
} CONTRIB; /* direct contribution */
typedef struct {
int sndx; /* source index (to CONTRIB array) */
float brt; /* brightness (for comparison) */
} CNTPTR; /* contribution pointer */
static CONTRIB *srccnt; /* source contributions in direct() */
static CNTPTR *cntord; /* source ordering in direct() */
static int maxcntr = 0; /* size of contribution arrays */
static int cntcmp(const void *p1, const void *p2);
void
marksources(void) /* find and mark source objects */
{
int foundsource = 0;
int i;
OBJREC *o, *m;
int ns;
/* initialize dispatch table */
initstypes();
/* find direct sources */
for (i = 0; i < nsceneobjs; i++) {
o = objptr(i);
if (!issurface(o->otype) || o->omod == OVOID)
continue;
/* find material */
m = findmaterial(o);
if (m == NULL)
continue;
if (m->otype == MAT_CLIP) {
markclip(m); /* special case for antimatter */
continue;
}
if (!islight(m->otype))
continue; /* not source modifier */
if (m->oargs.nfargs != (m->otype == MAT_GLOW ? 4 :
m->otype == MAT_SPOT ? 7 : 3))
objerror(m, USER, "bad # arguments");
if (m->oargs.farg[0] <= FTINY && (m->oargs.farg[1] <= FTINY) &
(m->oargs.farg[2] <= FTINY))
continue; /* don't bother */
if (m->otype == MAT_GLOW &&
o->otype != OBJ_SOURCE &&
m->oargs.farg[3] <= FTINY) {
foundsource += (ambounce > 0);
continue; /* don't track these */
}
if (sfun[o->otype].of == NULL ||
sfun[o->otype].of->setsrc == NULL)
objerror(o, USER, "illegal material");
if ((ns = newsource()) < 0)
goto memerr;
setsource(&source[ns], o);
if (m->otype == MAT_GLOW) {
source[ns].sflags |= SPROX;
source[ns].sl.prox = m->oargs.farg[3];
if (source[ns].sflags & SDISTANT) {
source[ns].sflags |= SSKIP;
foundsource += (ambounce > 0);
}
} else if (m->otype == MAT_SPOT) {
if (source[ns].sflags & SDISTANT)
objerror(o, WARNING,
"distant source is a spotlight");
source[ns].sflags |= SSPOT;
if ((source[ns].sl.s = makespot(m)) == NULL)
goto memerr;
if (source[ns].sflags & SFLAT &&
!checkspot(source[ns].sl.s,source[ns].snorm)) {
objerror(o, WARNING,
"invalid spotlight direction");
source[ns].sflags |= SSKIP;
}
}
foundsource += !(source[ns].sflags & SSKIP);
}
if (!foundsource) {
error(WARNING, "no light sources found");
return;
}
#if SHADCACHE
for (ns = 0; ns < nsources; ns++) /* initialize obstructor cache */
initobscache(ns);
#endif
/* PMAP: disable virtual sources */
if (!photonMapping)
markvirtuals(); /* find and add virtual sources */
/* allocate our contribution arrays */
maxcntr = nsources + MAXSPART; /* start with this many */
srccnt = (CONTRIB *)malloc(maxcntr*sizeof(CONTRIB));
cntord = (CNTPTR *)malloc(maxcntr*sizeof(CNTPTR));
if ((srccnt != NULL) & (cntord != NULL))
return;
memerr:
error(SYSTEM, "out of memory in marksources");
}
void
distantsources(void) /* only mark distant sources */
{
int i;
OBJREC *o, *m;
int ns;
/* initialize dispatch table */
initstypes();
/* sources needed for sourcehit() */
for (i = 0; i < nsceneobjs; i++) {
o = objptr(i);
if ((o->otype != OBJ_SOURCE) | (o->omod == OVOID))
continue;
/* find material */
m = findmaterial(o);
if (m == NULL)
continue;
if (!islight(m->otype))
continue; /* not source modifier */
if (m->oargs.nfargs != (m->otype == MAT_GLOW ? 4 :
m->otype == MAT_SPOT ? 7 : 3))
objerror(m, USER, "bad # arguments");
if (m->oargs.farg[0] <= FTINY && (m->oargs.farg[1] <= FTINY) &
(m->oargs.farg[2] <= FTINY))
continue; /* don't bother */
if (sfun[o->otype].of == NULL ||
sfun[o->otype].of->setsrc == NULL)
objerror(o, USER, "illegal material");
if ((ns = newsource()) < 0)
error(SYSTEM, "out of memory in distantsources");
setsource(&source[ns], o);
if (m->otype == MAT_GLOW) {
source[ns].sflags |= SPROX|SSKIP;
source[ns].sl.prox = m->oargs.farg[3];
} else if (m->otype == MAT_SPOT)
objerror(o, WARNING, "distant source is a spotlight");
}
}
void
freesources(void) /* free all source structures */
{
if (nsources > 0) {
#if SHADCACHE
while (nsources--)
freeobscache(&source[nsources]);
#endif
free((void *)source);
source = NULL;
nsources = 0;
}
markclip(NULL);
if (maxcntr <= 0)
return;
free((void *)srccnt);
srccnt = NULL;
free((void *)cntord);
cntord = NULL;
maxcntr = 0;
}
int
srcray( /* send a ray to a source, return domega */
RAY *sr, /* returned source ray */
RAY *r, /* ray which hit object */
SRCINDEX *si /* source sample index */
)
{
double d; /* distance to source */
SRCREC *srcp;
rayorigin(sr, SHADOW, r, NULL); /* ignore limits */
if (r == NULL)
sr->rmax = 0.0;
while ((d = nextssamp(sr, si)) != 0.0) {
sr->rsrc = si->sn; /* remember source */
srcp = source + si->sn;
if (srcp->sflags & SDISTANT) {
if (srcp->sflags & SSPOT && spotout(sr, srcp->sl.s))
continue;
return(1); /* sample OK */
}
/* local source */
/* check proximity */
if (srcp->sflags & SPROX && d > srcp->sl.prox)
continue;
/* check angle */
if (srcp->sflags & SSPOT) {
if (spotout(sr, srcp->sl.s))
continue;
/* adjust solid angle */
si->dom *= d*d;
d += srcp->sl.s->flen;
si->dom /= d*d;
}
return(1); /* sample OK */
}
return(0); /* no more samples */
}
void
srcvalue( /* punch ray to source and compute value */
RAY *r
)
{
SRCREC *sp;
sp = &source[r->rsrc];
if (sp->sflags & SVIRTUAL) { /* virtual source */
/* check intersection */
if (!(*ofun[sp->so->otype].funp)(sp->so, r))
return;
if (!rayshade(r, r->ro->omod)) /* compute contribution */
goto nomat;
rayparticipate(r);
return;
}
/* compute intersection */
if (sp->sflags & SDISTANT ? sourcehit(r) :
(*ofun[sp->so->otype].funp)(sp->so, r)) {
if (sp->sa.success >= 0)
sp->sa.success++;
if (!rayshade(r, r->ro->omod)) /* compute contribution */
goto nomat;
rayparticipate(r);
return;
}
/* we missed our mark! */
if (sp->sa.success < 0)
return; /* bitched already */
sp->sa.success -= AIMREQT;
if (sp->sa.success >= 0)
return; /* leniency */
sprintf(errmsg, "aiming failure for light source \"%s\"",
sp->so->oname);
error(WARNING, errmsg); /* issue warning */
return;
nomat:
objerror(r->ro, USER, "material not found");
}
static int
transillum( /* check if material is transparent illum */
OBJREC *m
)
{
m = findmaterial(m);
if (m == NULL)
return(1);
if (m->otype != MAT_ILLUM)
return(0);
return(!m->oargs.nsargs || !strcmp(m->oargs.sarg[0], VOIDID));
}
int
sourcehit( /* check to see if ray hit distant source */
RAY *r
)
{
int glowsrc = -1;
int transrc = -1;
int first, last;
int i;
if (r->rsrc >= 0) { /* check only one if aimed */
first = last = r->rsrc;
} else { /* otherwise check all */
first = 0; last = nsources-1;
}
for (i = first; i <= last; i++) {
if ((source[i].sflags & (SDISTANT|SVIRTUAL)) != SDISTANT)
continue;
/*
* Check to see if ray is within
* solid angle of source.
*/
if (2.*PI*(1. - DOT(source[i].sloc,r->rdir)) > source[i].ss2)
continue;
/* is it what we aimed for? */
if (i == r->rsrc) {
r->ro = source[i].so;
break;
}
/*
* If it's a glow or transparent illum, just remember it.
*/
if (source[i].sflags & SSKIP) {
if (glowsrc < 0)
glowsrc = i;
continue;
}
if (transillum(source[i].so)) {
if (transrc < 0)
transrc = i;
continue;
}
r->ro = source[i].so; /* otherwise, use first hit */
break;
}
/*
* Do we need fallback?
*/
if (r->ro == NULL) {
if (transrc >= 0 && r->crtype & (AMBIENT|SPECULAR))
return(0); /* avoid overcounting */
if (glowsrc >= 0)
r->ro = source[glowsrc].so;
else
return(0); /* nothing usable */
}
/*
* Assign object index
*/
r->robj = objndx(r->ro);
return(1);
}
static int
cntcmp( /* contribution compare (descending) */
const void *p1,
const void *p2
)
{
const CNTPTR *sc1 = (const CNTPTR *)p1;
const CNTPTR *sc2 = (const CNTPTR *)p2;
if (sc1->brt > sc2->brt)
return(-1);
if (sc1->brt < sc2->brt)
return(1);
return(0);
}
void
direct( /* add direct component */
RAY *r, /* ray that hit surface */
srcdirf_t *f, /* direct component coefficient function */
void *p /* data for f */
)
{
int sn;
CONTRIB *scp;
SRCINDEX si;
int nshadcheck, ncnts;
int nhits;
double prob, ourthresh, hwt;
RAY sr;
/* PMAP: Factor in direct photons (primarily for debugging/validation) */
/* PMAP: Also primary hook in lightflow mode, since this accounts for
direct _and_ indirect component */
if (directPhotonMapping
#ifdef PMAP_PHOTONFLOW
|| lightFlowPhotonMapping
#endif
) {
(*f)(r -> rcol, p, r -> ron, PI);
multDirectPmap(r);
return;
}
/* NOTE: srccnt and cntord global so no recursion */
if (nsources <= 0)
return; /* no sources?! */
/* potential contributions */
initsrcindex(&si);
for (sn = 0; srcray(&sr, r, &si); sn++) {
if (sn >= maxcntr) {
maxcntr = sn + MAXSPART;
srccnt = (CONTRIB *)realloc((void *)srccnt,
maxcntr*sizeof(CONTRIB));
cntord = (CNTPTR *)realloc((void *)cntord,
maxcntr*sizeof(CNTPTR));
if ((srccnt == NULL) | (cntord == NULL))
error(SYSTEM, "out of memory in direct");
}
cntord[sn].sndx = sn;
scp = srccnt + sn;
scp->sno = sr.rsrc;
#if SHADCACHE /* check shadow cache */
if (si.np == 1 && srcblocked(&sr)) {
cntord[sn].brt = 0.0;
continue;
}
#endif
/* compute coefficient */
(*f)(scp->coef, p, sr.rdir, si.dom);
cntord[sn].brt = intens(scp->coef);
if (cntord[sn].brt <= 0.0)
continue;
VCOPY(scp->dir, sr.rdir);
copycolor(sr.rcoef, scp->coef);
/* compute potential */
sr.revf = srcvalue;
rayvalue(&sr);
multcolor(sr.rcol, sr.rcoef);
copycolor(scp->val, sr.rcol);
cntord[sn].brt = bright(sr.rcol);
}
/* sort contributions */
qsort(cntord, sn, sizeof(CNTPTR), cntcmp);
{ /* find last */
int l, m;
ncnts = l = sn;
sn = 0;
while ((m = (sn + ncnts) >> 1) != l) {
if (cntord[m].brt > 0.0)
sn = m;
else
ncnts = m;
l = m;
}
}
if (ncnts == 0)
return; /* no contributions! */
/* accumulate tail */
for (sn = ncnts-1; sn > 0; sn--)
cntord[sn-1].brt += cntord[sn].brt;
/* compute number to check */
nshadcheck = pow((double)ncnts, shadcert) + .5;
/* modify threshold */
ourthresh = shadthresh / r->rweight;
/* test for shadows */
for (nhits = 0, hwt = 0.0, sn = 0; sn < ncnts;
hwt += (double)source[scp->sno].nhits /
(double)source[scp->sno].ntests,
sn++) {
/* check threshold */
if (sn >= MINSHADCNT &&
(sn+nshadcheck>=ncnts ? cntord[sn].brt :
cntord[sn].brt-cntord[sn+nshadcheck].brt)
< ourthresh*bright(r->rcol))
break;
scp = srccnt + cntord[sn].sndx;
/* test for hit */
rayorigin(&sr, SHADOW, r, NULL);
copycolor(sr.rcoef, scp->coef);
VCOPY(sr.rdir, scp->dir);
sr.rsrc = scp->sno;
/* keep statistics */
if (source[scp->sno].ntests++ > 0xfffffff0) {
source[scp->sno].ntests >>= 1;
source[scp->sno].nhits >>= 1;
}
if (localhit(&sr, &thescene) &&
( sr.ro != source[scp->sno].so ||
source[scp->sno].sflags & SFOLLOW )) {
/* follow entire path */
raycont(&sr);
if (trace != NULL)
(*trace)(&sr); /* trace execution */
if (bright(sr.rcol) <= FTINY) {
#if SHADCACHE
if ((scp <= srccnt || scp[-1].sno != scp->sno)
&& (scp >= srccnt+ncnts-1 ||
scp[1].sno != scp->sno))
srcblocker(&sr);
#endif
continue; /* missed! */
}
rayparticipate(&sr);
multcolor(sr.rcol, sr.rcoef);
copycolor(scp->val, sr.rcol);
} else if (trace != NULL &&
(source[scp->sno].sflags & (SDISTANT|SVIRTUAL|SFOLLOW))
== (SDISTANT|SFOLLOW) &&
sourcehit(&sr) && rayshade(&sr, sr.ro->omod)) {
(*trace)(&sr); /* trace execution */
/* skip call to rayparticipate() & scp->val update */
}
/* add contribution if hit */
addcolor(r->rcol, scp->val);
nhits++;
source[scp->sno].nhits++;
}
/* source hit rate */
if (hwt > FTINY)
hwt = (double)nhits / hwt;
else
hwt = 0.5;
#ifdef DEBUG
sprintf(errmsg, "%d tested, %d untested, %f conditional hit rate\n",
sn, ncnts-sn, hwt);
eputs(errmsg);
#endif
/* add in untested sources */
for ( ; sn < ncnts; sn++) {
scp = srccnt + cntord[sn].sndx;
prob = hwt * (double)source[scp->sno].nhits /
(double)source[scp->sno].ntests;
if (prob < 1.0)
scalecolor(scp->val, prob);
addcolor(r->rcol, scp->val);
}
}
void
srcscatter( /* compute source scattering into ray */
RAY *r
)
{
int oldsampndx;
int nsamps;
RAY sr;
SRCINDEX si;
double t, d;
double re, ge, be;
COLOR cvext;
int i, j;
if (r->rot >= FHUGE*.99 || r->gecc >= 1.-FTINY)
return; /* this can never work */
/* PMAP: do unconditional inscattering for volume photons */
if (!volumePhotonMapping && (r->slights == NULL || r->slights[0] == 0))
return;
if (ssampdist <= FTINY || (nsamps = r->rot/ssampdist + .5) < 1)
nsamps = 1;
#if MAXSSAMP
else if (nsamps > MAXSSAMP)
nsamps = MAXSSAMP;
#endif
oldsampndx = samplendx;
samplendx = random()&0x7fff; /* randomize */
for (i = volumePhotonMapping ? 1 : r->slights[0]; i > 0; i--) {
/* for each source OR once if volume photon map enabled */
for (j = 0; j < nsamps; j++) { /* for each sample position */
samplendx++;
t = r->rot * (j+frandom())/nsamps;
/* extinction */
re = t*colval(r->cext,RED);
ge = t*colval(r->cext,GRN);
be = t*colval(r->cext,BLU);
setcolor(cvext, re > 92. ? 0. : exp(-re),
ge > 92. ? 0. : exp(-ge),
be > 92. ? 0. : exp(-be));
if (intens(cvext) <= FTINY)
break; /* too far away */
sr.rorg[0] = r->rorg[0] + r->rdir[0]*t;
sr.rorg[1] = r->rorg[1] + r->rdir[1]*t;
sr.rorg[2] = r->rorg[2] + r->rdir[2]*t;
if (!volumePhotonMapping) {
initsrcindex(&si); /* sample ray to this source */
si.sn = r->slights[i];
nopart(&si, &sr);
if (!srcray(&sr, NULL, &si) ||
sr.rsrc != r->slights[i])
continue; /* no path */
#if SHADCACHE
if (srcblocked(&sr)) /* check shadow cache */
continue;
#endif
copycolor(sr.cext, r->cext);
copycolor(sr.albedo, r->albedo);
sr.gecc = r->gecc;
sr.slights = r->slights;
rayvalue(&sr); /* eval. source ray */
if (bright(sr.rcol) <= FTINY) {
#if SHADCACHE
srcblocker(&sr); /* add blocker to cache */
#endif
continue;
}
if (r->gecc <= FTINY) /* compute P(theta) */
d = 1.;
else {
d = DOT(r->rdir, sr.rdir);
d = 1. + r->gecc*r->gecc - 2.*r->gecc*d;
d = (1. - r->gecc*r->gecc) / (d*sqrt(d));
}
/* other factors */
d *= si.dom * r->rot / (4.*PI*nsamps);
scalecolor(sr.rcol, d);
} else {
/* PMAP: Add ambient inscattering from
* volume photons; note we reverse the
* incident ray direction since we're
* now in *backward* raytracing mode! */
sr.rdir [0] = -r -> rdir [0];
sr.rdir [1] = -r -> rdir [1];
sr.rdir [2] = -r -> rdir [2];
sr.gecc = r -> gecc;
inscatterVolumePmap(&sr, sr.rcol);
scalecolor(sr.rcol, r -> rot / nsamps);
}
multcolor(sr.rcol, r->cext);
multcolor(sr.rcol, r->albedo);
multcolor(sr.rcol, cvext);
addcolor(r->rcol, sr.rcol); /* add it in */
}
}
samplendx = oldsampndx;
}
/****************************************************************
* The following macros were separated from the m_light() routine
* because they are very nasty and difficult to understand.
*/
/* illumblock *
*
* We cannot allow an illum to pass to another illum, because that
* would almost certainly constitute overcounting.
* However, we do allow an illum to pass to another illum
* that is actually going to relay to a virtual light source.
* We also prevent an illum from passing to a glow; this provides a
* convenient mechanism for defining detailed light source
* geometry behind (or inside) an effective radiator.
*/
static int
weaksrcmat(OBJREC *m) /* identify material */
{
m = findmaterial(m);
if (m == NULL) return(0);
return((m->otype==MAT_ILLUM) | (m->otype==MAT_GLOW));
}
#define illumblock(m, r) (!(source[r->rsrc].sflags&SVIRTUAL) && \
r->rod > 0.0 && \
weaksrcmat(source[r->rsrc].so))
/* wrongsource *
*
* This source is the wrong source (ie. overcounted) if we are
* aimed to a different source than the one we hit and the one
* we hit is not an illum that should be passed.
*/
#define wrongsource(m, r) (r->rsrc>=0 && source[r->rsrc].so!=r->ro && \
(m->otype!=MAT_ILLUM || illumblock(m,r)))
/* distglow *
*
* A distant glow is an object that sometimes acts as a light source,
* but is too far away from the test point to be one in this case.
* (Glows with negative radii should NEVER participate in illumination.)
*/
#define distglow(m, r, d) (m->otype==MAT_GLOW && \
m->oargs.farg[3] >= -FTINY && \
d > m->oargs.farg[3])
/* badcomponent *
*
* We must avoid counting light sources in the ambient calculation,
* since the direct component is handled separately. Therefore, any
* ambient ray which hits an active light source must be discarded.
* The same is true for stray specular samples, since the specular
* contribution from light sources is calculated separately.
*/
/* PMAP: Also avoid counting sources via transferred ambient rays (e.g.
* through glass) when photon mapping is enabled, as these indirect
* components are already accounted for.
*/
#define badcomponent(m, r) (srcRayInPmap(r) || \
(r->crtype&(AMBIENT|SPECULAR) && \
!(r->crtype&SHADOW || r->rod < 0.0 || \
/* not 100% correct */ distglow(m, r, r->rot))))
/* passillum *
*
* An illum passes to another material type when we didn't hit it
* on purpose (as part of a direct calculation), or it is relaying
* a virtual light source.
*/
#define passillum(m, r) (m->otype==MAT_ILLUM && \
(r->rsrc<0 || source[r->rsrc].so!=r->ro || \
source[r->rsrc].sflags&SVIRTUAL))
/* srcignore *
*
* The -dv flag is normally on for sources to be visible.
*/
#define srcignore(m, r) !(directvis || r->crtype&SHADOW || \
distglow(m, r, raydist(r,PRIMARY)))
int
m_light( /* ray hit a light source */
OBJREC *m,
RAY *r
)
{
/* check for over-counting */
if (badcomponent(m, r)) {
setcolor(r->rcoef, 0.0, 0.0, 0.0);
return(1);
}
if (wrongsource(m, r)) {
setcolor(r->rcoef, 0.0, 0.0, 0.0);
return(1);
}
/* check for passed illum */
if (passillum(m, r)) {
if (m->oargs.nsargs && strcmp(m->oargs.sarg[0], VOIDID))
return(rayshade(r,lastmod(objndx(m),m->oargs.sarg[0])));
raytrans(r);
return(1);
}
/* check for invisibility */
if (srcignore(m, r)) {
setcolor(r->rcoef, 0.0, 0.0, 0.0);
return(1);
}
/* otherwise treat as source */
/* check for behind */
if (r->rod < 0.0)
return(1);
/* check for outside spot */
if (m->otype==MAT_SPOT && spotout(r, makespot(m)))
return(1);
/* get distribution pattern */
raytexture(r, m->omod);
/* get source color */
setcolor(r->rcol, m->oargs.farg[0],
m->oargs.farg[1],
m->oargs.farg[2]);
/* modify value */
multcolor(r->rcol, r->pcol);
return(1);
}

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