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RadiancePmap/virtuals.c
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virtuals.c
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#ifndef lint
static const char RCSid[] = "$Id: virtuals.c,v 2.25 2021/02/12 00:41:19 greg Exp $";
#endif
/*
* Routines for simulating virtual light sources
* Thus far, we only support planar mirrors.
*
* External symbols declared in source.h
*/
#include "copyright.h"
#include "ray.h"
#include "otypes.h"
#include "otspecial.h"
#include "source.h"
#include "random.h"
#define MINSAMPLES 16 /* minimum number of pretest samples */
#define STESTMAX 32 /* maximum seeks per sample */
static OBJECT *vobject; /* virtual source objects */
static int nvobjects = 0; /* number of virtual source objects */
static int
isident4(MAT4 m)
{
int i, j;
for (i = 4; i--; )
for (j = 4; j--; )
if (!FABSEQ(m[i][j], i==j))
return(0);
return(1);
}
void
markvirtuals(void) /* find and mark virtual sources */
{
OBJREC *o;
int i;
/* check number of direct relays */
if (directrelay <= 0)
return;
/* find virtual source objects */
for (i = 0; i < nsceneobjs; i++) {
o = objptr(i);
if (!issurface(o->otype) || o->omod == OVOID)
continue;
if (!isvlight(vsmaterial(o)->otype))
continue;
if (sfun[o->otype].of == NULL ||
sfun[o->otype].of->getpleq == NULL) {
objerror(o,WARNING,"secondary sources not supported");
continue;
}
if (nvobjects == 0)
vobject = (OBJECT *)malloc(sizeof(OBJECT));
else
vobject = (OBJECT *)realloc((void *)vobject,
(unsigned)(nvobjects+1)*sizeof(OBJECT));
if (vobject == NULL)
error(SYSTEM, "out of memory in addvirtuals");
vobject[nvobjects++] = i;
}
if (nvobjects == 0)
return;
#ifdef DEBUG
fprintf(stderr, "found %d virtual source objects\n", nvobjects);
#endif
/* append virtual sources */
for (i = nsources; i-- > 0; )
addvirtuals(i, directrelay);
/* done with our object list */
free((void *)vobject);
nvobjects = 0;
}
void
addvirtuals( /* add virtuals associated with source */
int sn,
int nr
)
{
int i;
/* check relay limit first */
if (nr <= 0)
return;
if (source[sn].sflags & SSKIP)
return;
/* check each virtual object for projection */
for (i = 0; i < nvobjects; i++)
/* vproject() calls us recursively */
vproject(objptr(vobject[i]), sn, nr-1);
}
void
vproject( /* create projected source(s) if they exist */
OBJREC *o,
int sn,
int n
)
{
int i;
VSMATERIAL *vsmat;
MAT4 proj;
int ns;
if (o == source[sn].so) /* objects cannot project themselves */
return;
/* get virtual source material */
vsmat = sfun[vsmaterial(o)->otype].mf;
/* project virtual sources */
for (i = 0; i < vsmat->nproj; i++)
if ((*vsmat->vproj)(proj, o, &source[sn], i))
if ((ns = makevsrc(o, sn, proj)) >= 0) {
source[ns].sa.sv.pn = i;
#ifdef DEBUG
virtverb(ns, stderr);
#endif
addvirtuals(ns, n);
}
}
OBJREC *
vsmaterial( /* get virtual source material pointer */
OBJREC *o
)
{
int i;
OBJREC *m;
i = o->omod;
m = findmaterial(o);
if (m == NULL)
return(objptr(i));
if (m->otype != MAT_ILLUM || m->oargs.nsargs < 1 ||
!strcmp(m->oargs.sarg[0], VOIDID) ||
(i = lastmod(objndx(m), m->oargs.sarg[0])) == OVOID)
return(m); /* direct modifier */
return(objptr(i)); /* illum alternate */
}
int
makevsrc( /* make virtual source if reasonable */
OBJREC *op,
int sn,
MAT4 pm
)
{
FVECT nsloc, nsnorm, ocent, v;
double maxrad2, d;
int nsflags;
SPOT theirspot, ourspot;
int i;
/* check for no-op */
if (isident4(pm))
return(0);
nsflags = source[sn].sflags | (SVIRTUAL|SSPOT|SFOLLOW);
/* get object center and max. radius */
maxrad2 = getdisk(ocent, op, sn);
if (maxrad2 <= FTINY) /* too small? */
return(-1);
/* get location and spot */
if (source[sn].sflags & SDISTANT) { /* distant source */
if (source[sn].sflags & SPROX)
return(-1); /* should never get here! */
multv3(nsloc, source[sn].sloc, pm);
normalize(nsloc);
VCOPY(ourspot.aim, ocent);
ourspot.siz = PI*maxrad2;
ourspot.flen = -1.;
if (source[sn].sflags & SSPOT) {
multp3(theirspot.aim, source[sn].sl.s->aim, pm);
/* adjust for source size */
d = sqrt(dist2(ourspot.aim, theirspot.aim));
d = sqrt(source[sn].sl.s->siz/PI) + d*source[sn].srad;
theirspot.siz = PI*d*d;
ourspot.flen = theirspot.flen = source[sn].sl.s->flen;
d = ourspot.siz;
if (!commonbeam(&ourspot, &theirspot, nsloc))
return(-1); /* no overlap */
if (ourspot.siz < d-FTINY) { /* it shrunk */
d = beamdisk(v, op, &ourspot, nsloc);
if (d <= FTINY)
return(-1);
if (d < maxrad2) {
maxrad2 = d;
VCOPY(ocent, v);
}
}
}
} else { /* local source */
multp3(nsloc, source[sn].sloc, pm);
for (i = 0; i < 3; i++)
ourspot.aim[i] = ocent[i] - nsloc[i];
if ((d = normalize(ourspot.aim)) == 0.)
return(-1); /* at source!! */
if (source[sn].sflags & SPROX && d > source[sn].sl.prox)
return(-1); /* too far away */
ourspot.flen = 0.;
/* adjust for source size */
d = (sqrt(maxrad2) + source[sn].srad) / d;
if (d < 1.-FTINY)
ourspot.siz = 2.*PI*(1. - sqrt(1.-d*d));
else
nsflags &= ~SSPOT;
if (source[sn].sflags & SSPOT) {
theirspot = *(source[sn].sl.s);
multv3(theirspot.aim, source[sn].sl.s->aim, pm);
normalize(theirspot.aim);
if (nsflags & SSPOT) {
ourspot.flen = theirspot.flen;
d = ourspot.siz;
if (!commonspot(&ourspot, &theirspot, nsloc))
return(-1); /* no overlap */
} else {
nsflags |= SSPOT;
ourspot = theirspot;
d = 2.*ourspot.siz;
}
if (ourspot.siz < d-FTINY) { /* it shrunk */
d = spotdisk(v, op, &ourspot, nsloc);
if (d <= FTINY)
return(-1);
if (d < maxrad2) {
maxrad2 = d;
VCOPY(ocent, v);
}
}
}
if (source[sn].sflags & SFLAT) { /* behind source? */
multv3(nsnorm, source[sn].snorm, pm);
normalize(nsnorm);
if (nsflags & SSPOT && !checkspot(&ourspot, nsnorm))
return(-1);
}
}
/* pretest visibility */
nsflags = vstestvis(nsflags, op, ocent, maxrad2, sn);
if (nsflags & SSKIP)
return(-1); /* obstructed */
/* it all checks out, so make it */
if ((i = newsource()) < 0)
goto memerr;
source[i].sflags = nsflags;
VCOPY(source[i].sloc, nsloc);
multv3(source[i].ss[SU], source[sn].ss[SU], pm);
multv3(source[i].ss[SV], source[sn].ss[SV], pm);
if (nsflags & SFLAT)
VCOPY(source[i].snorm, nsnorm);
else
multv3(source[i].ss[SW], source[sn].ss[SW], pm);
source[i].srad = source[sn].srad;
source[i].ss2 = source[sn].ss2;
if (nsflags & SSPOT) {
if ((source[i].sl.s = (SPOT *)malloc(sizeof(SPOT))) == NULL)
goto memerr;
*(source[i].sl.s) = ourspot;
}
if (nsflags & SPROX)
source[i].sl.prox = source[sn].sl.prox;
source[i].sa.sv.sn = sn;
source[i].so = op;
return(i);
memerr:
error(SYSTEM, "out of memory in makevsrc");
return -1; /* pro forma return */
}
double
getdisk( /* get visible object disk */
FVECT oc,
OBJREC *op,
int sn
)
{
double rad2, roffs, offs, d, rd, rdoto;
FVECT rnrm, nrm;
/* first, use object getdisk function */
rad2 = getmaxdisk(oc, op);
if (!(source[sn].sflags & SVIRTUAL))
return(rad2); /* all done for normal source */
/* check for correct side of relay surface */
roffs = getplaneq(rnrm, source[sn].so);
rd = DOT(rnrm, source[sn].sloc); /* source projection */
if (!(source[sn].sflags & SDISTANT))
rd -= roffs;
d = DOT(rnrm, oc) - roffs; /* disk distance to relay plane */
if ((d > 0.) ^ (rd > 0.))
return(rad2); /* OK if opposite sides */
if (d*d >= rad2)
return(0.); /* no relay is possible */
/* we need a closer look */
offs = getplaneq(nrm, op);
rdoto = DOT(rnrm, nrm);
if (d*d >= rad2*(1.-rdoto*rdoto))
return(0.); /* disk entirely on projection side */
/* should shrink disk but I'm lazy */
return(rad2);
}
int
vstestvis( /* pretest source visibility */
int f, /* virtual source flags */
OBJREC *o, /* relay object */
FVECT oc, /* relay object center */
double or2, /* relay object radius squared */
int sn /* target source number */
)
{
RAY sr;
FVECT onorm;
double offsdir[3];
SRCINDEX si;
double or, d, d1;
int stestlim, ssn;
int nhit, nok;
int i, n;
/* return if pretesting disabled */
if (vspretest <= 0)
return(f);
/* get surface normal */
getplaneq(onorm, o);
/* set number of rays to sample */
if (source[sn].sflags & SDISTANT) {
/* 32. == heuristic constant */
n = 32.*or2/(thescene.cusize*thescene.cusize)*vspretest + .5;
} else {
VSUB(offsdir, source[sn].sloc, oc);
d = DOT(offsdir,offsdir);
if (d <= FTINY)
n = 2.*PI * vspretest + .5;
else
n = 2.*PI * (1.-sqrt(1./(1.+or2/d)))*vspretest + .5;
}
if (n < MINSAMPLES) n = MINSAMPLES;
#ifdef DEBUG
fprintf(stderr, "pretesting source %d in object %s with %d rays\n",
sn, o->oname, n);
#endif
/* sample */
or = sqrt(or2);
stestlim = n*STESTMAX;
ssn = 0;
nhit = nok = 0;
initsrcindex(&si);
while (n-- > 0) {
/* get sample point */
do {
if (ssn >= stestlim) {
#ifdef DEBUG
fprintf(stderr, "\ttoo hard to hit\n");
#endif
return(f); /* too small a target! */
}
multisamp(offsdir, 3, urand(sn*931+5827+ssn));
for (i = 0; i < 3; i++)
offsdir[i] = or*(1. - 2.*offsdir[i]);
ssn++;
d = 1. - DOT(offsdir, onorm);
for (i = 0; i < 3; i++) {
sr.rorg[i] = oc[i] + offsdir[i] + d*onorm[i];
sr.rdir[i] = -onorm[i];
}
sr.rmax = 0.0;
rayorigin(&sr, PRIMARY, NULL, NULL);
} while (!(*ofun[o->otype].funp)(o, &sr));
/* check against source */
VCOPY(sr.rorg, sr.rop); /* starting from intersection */
samplendx++;
if (si.sp >= si.np-1 ||
!srcray(&sr, NULL, &si) || sr.rsrc != sn) {
si.sn = sn-1; /* reset index to our source */
si.np = 0;
if (!srcray(&sr, NULL, &si) || sr.rsrc != sn)
continue; /* can't get there from here */
}
sr.revf = srcvalue;
rayvalue(&sr); /* check sample validity */
if ((d = bright(sr.rcol)) <= FTINY)
continue;
nok++; /* got sample; check obstructions */
rayclear(&sr);
sr.revf = raytrace;
rayvalue(&sr);
if ((d1 = bright(sr.rcol)) > FTINY) {
if (d - d1 > FTINY) {
#ifdef DEBUG
fprintf(stderr, "\tpartially shadowed\n");
#endif
return(f); /* intervening transmitter */
}
nhit++;
}
if (nhit > 0 && nhit < nok) {
#ifdef DEBUG
fprintf(stderr, "\tpartially occluded\n");
#endif
return(f); /* need to shadow test */
}
}
if (nhit == 0) {
#ifdef DEBUG
fprintf(stderr, "\t0%% hit rate\n");
#endif
return(f | SSKIP); /* 0% hit rate: totally occluded */
}
#ifdef DEBUG
fprintf(stderr, "\t100%% hit rate\n");
#endif
return(f & ~SFOLLOW); /* 100% hit rate: no occlusion */
}
#ifdef DEBUG
void
virtverb( /* print verbose description of virtual source */
int sn,
FILE *fp
)
{
fprintf(fp, "%s virtual source %d in %s %s\n",
source[sn].sflags & SDISTANT ? "distant" : "local",
sn, ofun[source[sn].so->otype].funame,
source[sn].so->oname);
fprintf(fp, "\tat (%f,%f,%f)\n",
source[sn].sloc[0], source[sn].sloc[1], source[sn].sloc[2]);
fprintf(fp, "\tlinked to source %d (%s)\n",
source[sn].sa.sv.sn, source[source[sn].sa.sv.sn].so->oname);
if (source[sn].sflags & SFOLLOW)
fprintf(fp, "\talways followed\n");
else
fprintf(fp, "\tnever followed\n");
if (!(source[sn].sflags & SSPOT))
return;
fprintf(fp, "\twith spot aim (%f,%f,%f) and size %f\n",
source[sn].sl.s->aim[0], source[sn].sl.s->aim[1],
source[sn].sl.s->aim[2], source[sn].sl.s->siz);
}
#endif
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