static int /* cast source ray to first blocker */
castshadow(int sn, FVECT rorg, FVECT rdir)
{
RAY rt;
VCOPY(rt.rorg, rorg);
VCOPY(rt.rdir, rdir);
rt.rmax = 0;
rayorigin(&rt, PRIMARY, NULL, NULL);
/* check for intersection */
while (localhit(&rt, &thescene)) {
RAY rt1 = rt; /* pretend we were aimed at source */
rt1.crtype |= rt1.rtype = SHADOW;
rt1.rdir[0] = -rt.rdir[0];
rt1.rdir[1] = -rt.rdir[1];
rt1.rdir[2] = -rt.rdir[2];
rt1.rod = -rt.rod;
VSUB(rt1.rorg, rt.rop, rt.rdir);
rt1.rot = 1.;
rt1.rsrc = sn;
/* record blocker */
if (srcblocker(&rt1))
return(1);
/* move past failed blocker */
VSUM(rt.rorg, rt.rop, rt.rdir, FTINY);
rayclear(&rt); /* & try again... */
}
return(0); /* found no blockers */
}
extern int
o_instance( /* compute ray intersection with octree */
OBJREC *o,
register RAY *r
)
{
RAY rcont;
double d;
register INSTANCE *ins;
register int i;
/* get the octree */
ins = getinstance(o, IO_ALL);
/* copy and transform ray */
rcont = *r;
multp3(rcont.rorg, r->rorg, ins->x.b.xfm);
multv3(rcont.rdir, r->rdir, ins->x.b.xfm);
for (i = 0; i < 3; i++)
rcont.rdir[i] /= ins->x.b.sca;
rcont.rmax *= ins->x.b.sca;
/* clear and trace it */
rayclear(&rcont);
if (!localhit(&rcont, &ins->obj->scube))
return(0); /* missed */
if (rcont.rot * ins->x.f.sca >= r->rot)
return(0); /* not close enough */
if (o->omod != OVOID) { /* if we have modifier, use it */
r->ro = o;
r->rox = NULL;
} else { /* else use theirs */
r->ro = rcont.ro;
if (rcont.rox != NULL) {
newrayxf(r); /* allocate transformation */
/* NOTE: r->rox may equal rcont.rox! */
multmat4(r->rox->f.xfm, rcont.rox->f.xfm, ins->x.f.xfm);
r->rox->f.sca = rcont.rox->f.sca * ins->x.f.sca;
multmat4(r->rox->b.xfm, ins->x.b.xfm, rcont.rox->b.xfm);
r->rox->b.sca = ins->x.b.sca * rcont.rox->b.sca;
} else
r->rox = &ins->x;
}
/* transform it back */
r->rot = rcont.rot * ins->x.f.sca;
multp3(r->rop, rcont.rop, ins->x.f.xfm);
multv3(r->ron, rcont.ron, ins->x.f.xfm);
multv3(r->pert, rcont.pert, ins->x.f.xfm);
d = 1./ins->x.f.sca;
for (i = 0; i < 3; i++) {
r->ron[i] *= d;
r->pert[i] *= d;
}
r->rod = rcont.rod;
r->uv[0] = rcont.uv[0];
r->uv[1] = rcont.uv[1];
/* return hit */
return(1);
}
static void
ray_pchild( /* process rays (never returns) */
int fd_in,
int fd_out
)
{
int n;
register int i;
/* flag child process for quit() */
ray_pnprocs = -1;
/* read each ray request set */
while ((n = read(fd_in, (char *)r_queue, sizeof(r_queue))) > 0) {
int n2;
if (n < sizeof(RAY))
break;
/* get smuggled set length */
n2 = sizeof(RAY)*r_queue[0].crtype - n;
if (n2 < 0)
error(INTERNAL, "buffer over-read in ray_pchild()");
if (n2 > 0) { /* read the rest of the set */
i = readbuf(fd_in, (char *)r_queue + n, n2);
if (i != n2)
break;
n += n2;
}
n /= sizeof(RAY);
/* evaluate rays */
for (i = 0; i < n; i++) {
r_queue[i].crtype = r_queue[i].rtype;
r_queue[i].parent = NULL;
r_queue[i].clipset = NULL;
r_queue[i].slights = NULL;
r_queue[i].rlvl = 0;
samplendx += samplestep;
rayclear(&r_queue[i]);
rayvalue(&r_queue[i]);
}
/* write back our results */
i = writebuf(fd_out, (char *)r_queue, sizeof(RAY)*n);
if (i != sizeof(RAY)*n)
error(SYSTEM, "write error in ray_pchild()");
}
if (n)
error(SYSTEM, "read error in ray_pchild()");
ambsync();
quit(0); /* normal exit */
}
extern int
rayorigin( /* start new ray from old one */
RAY *r,
int rt,
const RAY *ro,
const COLOR rc
)
{
double rw, re;
/* assign coefficient/weight */
if (rc == NULL) {
rw = 1.0;
setcolor(r->rcoef, 1., 1., 1.);
} else {
rw = intens(rc);
if (rc != r->rcoef)
copycolor(r->rcoef, rc);
}
if ((r->parent = ro) == NULL) { /* primary ray */
r->rlvl = 0;
r->rweight = rw;
r->crtype = r->rtype = rt;
r->rsrc = -1;
r->clipset = NULL;
r->revf = raytrace;
copycolor(r->cext, cextinction);
copycolor(r->albedo, salbedo);
r->gecc = seccg;
r->slights = NULL;
} else { /* spawned ray */
if (ro->rot >= FHUGE) {
memset(r, 0, sizeof(RAY));
return(-1); /* illegal continuation */
}
r->rlvl = ro->rlvl;
if (rt & RAYREFL) {
r->rlvl++;
r->rsrc = -1;
r->clipset = ro->clipset;
r->rmax = 0.0;
} else {
r->rsrc = ro->rsrc;
r->clipset = ro->newcset;
r->rmax = ro->rmax <= FTINY ? 0.0 : ro->rmax - ro->rot;
}
r->revf = ro->revf;
copycolor(r->cext, ro->cext);
copycolor(r->albedo, ro->albedo);
r->gecc = ro->gecc;
r->slights = ro->slights;
r->crtype = ro->crtype | (r->rtype = rt);
VCOPY(r->rorg, ro->rop);
r->rweight = ro->rweight * rw;
/* estimate extinction */
re = colval(ro->cext,RED) < colval(ro->cext,GRN) ?
colval(ro->cext,RED) : colval(ro->cext,GRN);
if (colval(ro->cext,BLU) < re) re = colval(ro->cext,BLU);
re *= ro->rot;
if (re > 0.1) {
if (re > 92.) {
r->rweight = 0.0;
} else {
r->rweight *= exp(-re);
}
}
}
rayclear(r);
if (r->rweight <= 0.0) /* check for expiration */
return(-1);
if (r->crtype & SHADOW) /* shadow commitment */
return(0);
if (maxdepth <= 0 && rc != NULL) { /* Russian roulette */
if (minweight <= 0.0)
error(USER, "zero ray weight in Russian roulette");
if (maxdepth < 0 && r->rlvl > -maxdepth)
return(-1); /* upper reflection limit */
if (r->rweight >= minweight)
return(0);
if (frandom() > r->rweight/minweight)
return(-1);
rw = minweight/r->rweight; /* promote survivor */
scalecolor(r->rcoef, rw);
r->rweight = minweight;
return(0);
}
return(r->rweight >= minweight && r->rlvl <= abs(maxdepth) ? 0 : -1);
}
static void
ashiksamp( /* sample anisotropic Ashikhmin-Shirley specular */
ASHIKDAT *np
)
{
RAY sr;
FVECT h;
double rv[2], dtmp;
double cosph, sinph, costh, sinth;
int maxiter, ntrials, nstarget, nstaken;
int i;
if (np->specfl & SPA_BADU ||
rayorigin(&sr, SPECULAR, np->rp, np->scolor) < 0)
return;
nstarget = 1;
if (specjitter > 1.5) { /* multiple samples? */
nstarget = specjitter*np->rp->rweight + .5;
if (sr.rweight <= minweight*nstarget)
nstarget = sr.rweight/minweight;
if (nstarget > 1) {
dtmp = 1./nstarget;
scalecolor(sr.rcoef, dtmp);
sr.rweight *= dtmp;
} else
nstarget = 1;
}
dimlist[ndims++] = (int)(size_t)np->mp;
maxiter = MAXITER*nstarget;
for (nstaken = ntrials = 0; nstaken < nstarget &&
ntrials < maxiter; ntrials++) {
if (ntrials)
dtmp = frandom();
else
dtmp = urand(ilhash(dimlist,ndims)+647+samplendx);
multisamp(rv, 2, dtmp);
dtmp = 2.*PI * rv[0];
cosph = sqrt(np->v_power + 1.) * tcos(dtmp);
sinph = sqrt(np->u_power + 1.) * tsin(dtmp);
dtmp = 1./sqrt(cosph*cosph + sinph*sinph);
cosph *= dtmp;
sinph *= dtmp;
costh = pow(rv[1], 1./(np->u_power*cosph*cosph+np->v_power*sinph*sinph+1.));
if (costh <= FTINY)
continue;
sinth = sqrt(1. - costh*costh);
for (i = 0; i < 3; i++)
h[i] = cosph*sinth*np->u[i] + sinph*sinth*np->v[i] + costh*np->pnorm[i];
if (nstaken)
rayclear(&sr);
dtmp = -2.*DOT(h, np->rp->rdir);
VSUM(sr.rdir, np->rp->rdir, h, dtmp);
/* sample rejection test */
if (DOT(sr.rdir, np->rp->ron) <= FTINY)
continue;
checknorm(sr.rdir);
rayvalue(&sr);
multcolor(sr.rcol, sr.rcoef);
addcolor(np->rp->rcol, sr.rcol);
++nstaken;
}
ndims--;
}
static void
agaussamp( /* sample anisotropic Gaussian specular */
ANISODAT *np
)
{
RAY sr;
FVECT h;
double rv[2];
double d, sinp, cosp;
COLOR scol;
int maxiter, ntrials, nstarget, nstaken;
int i;
/* compute reflection */
if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL &&
rayorigin(&sr, SPECULAR, np->rp, np->scolor) == 0) {
nstarget = 1;
if (specjitter > 1.5) { /* multiple samples? */
nstarget = specjitter*np->rp->rweight + .5;
if (sr.rweight <= minweight*nstarget)
nstarget = sr.rweight/minweight;
if (nstarget > 1) {
d = 1./nstarget;
scalecolor(sr.rcoef, d);
sr.rweight *= d;
} else
nstarget = 1;
}
setcolor(scol, 0., 0., 0.);
dimlist[ndims++] = (int)(size_t)np->mp;
maxiter = MAXITER*nstarget;
for (nstaken = ntrials = 0; nstaken < nstarget &&
ntrials < maxiter; ntrials++) {
if (ntrials)
d = frandom();
else
d = urand(ilhash(dimlist,ndims)+samplendx);
multisamp(rv, 2, d);
d = 2.0*PI * rv[0];
cosp = tcos(d) * np->u_alpha;
sinp = tsin(d) * np->v_alpha;
d = 1./sqrt(cosp*cosp + sinp*sinp);
cosp *= d;
sinp *= d;
if ((0. <= specjitter) & (specjitter < 1.))
rv[1] = 1.0 - specjitter*rv[1];
if (rv[1] <= FTINY)
d = 1.0;
else
d = sqrt(-log(rv[1]) /
(cosp*cosp/(np->u_alpha*np->u_alpha) +
sinp*sinp/(np->v_alpha*np->v_alpha)));
for (i = 0; i < 3; i++)
h[i] = np->pnorm[i] +
d*(cosp*np->u[i] + sinp*np->v[i]);
d = -2.0 * DOT(h, np->rp->rdir) / (1.0 + d*d);
VSUM(sr.rdir, np->rp->rdir, h, d);
/* sample rejection test */
if ((d = DOT(sr.rdir, np->rp->ron)) <= FTINY)
continue;
checknorm(sr.rdir);
if (nstarget > 1) { /* W-G-M-D adjustment */
if (nstaken) rayclear(&sr);
rayvalue(&sr);
d = 2./(1. + np->rp->rod/d);
scalecolor(sr.rcol, d);
addcolor(scol, sr.rcol);
} else {
rayvalue(&sr);
multcolor(sr.rcol, sr.rcoef);
addcolor(np->rp->rcol, sr.rcol);
}
++nstaken;
}
if (nstarget > 1) { /* final W-G-M-D weighting */
multcolor(scol, sr.rcoef);
d = (double)nstarget/ntrials;
scalecolor(scol, d);
addcolor(np->rp->rcol, scol);
}
ndims--;
}
/* compute transmission */
copycolor(sr.rcoef, np->mcolor); /* modify by material color */
scalecolor(sr.rcoef, np->tspec);
if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN &&
rayorigin(&sr, SPECULAR, np->rp, sr.rcoef) == 0) {
nstarget = 1;
if (specjitter > 1.5) { /* multiple samples? */
nstarget = specjitter*np->rp->rweight + .5;
if (sr.rweight <= minweight*nstarget)
nstarget = sr.rweight/minweight;
if (nstarget > 1) {
d = 1./nstarget;
scalecolor(sr.rcoef, d);
sr.rweight *= d;
} else
nstarget = 1;
}
dimlist[ndims++] = (int)(size_t)np->mp;
maxiter = MAXITER*nstarget;
for (nstaken = ntrials = 0; nstaken < nstarget &&
ntrials < maxiter; ntrials++) {
if (ntrials)
d = frandom();
else
d = urand(ilhash(dimlist,ndims)+1823+samplendx);
multisamp(rv, 2, d);
d = 2.0*PI * rv[0];
cosp = tcos(d) * np->u_alpha;
sinp = tsin(d) * np->v_alpha;
d = 1./sqrt(cosp*cosp + sinp*sinp);
cosp *= d;
sinp *= d;
if ((0. <= specjitter) & (specjitter < 1.))
rv[1] = 1.0 - specjitter*rv[1];
if (rv[1] <= FTINY)
d = 1.0;
else
d = sqrt(-log(rv[1]) /
(cosp*cosp/(np->u_alpha*np->u_alpha) +
sinp*sinp/(np->v_alpha*np->v_alpha)));
for (i = 0; i < 3; i++)
sr.rdir[i] = np->prdir[i] +
d*(cosp*np->u[i] + sinp*np->v[i]);
if (DOT(sr.rdir, np->rp->ron) >= -FTINY)
continue;
normalize(sr.rdir); /* OK, normalize */
if (nstaken) /* multi-sampling */
rayclear(&sr);
rayvalue(&sr);
multcolor(sr.rcol, sr.rcoef);
addcolor(np->rp->rcol, sr.rcol);
++nstaken;
}
ndims--;
}
}
