static int
ambsample( /* initial ambient division sample */
AMBHEMI *hp,
int i,
int j,
int n
)
{
AMBSAMP *ap = &ambsam(hp,i,j);
RAY ar;
int hlist[3], ii;
double spt[2], zd;
/* generate hemispherical sample */
/* ambient coefficient for weight */
if (ambacc > FTINY)
setcolor(ar.rcoef, AVGREFL, AVGREFL, AVGREFL);
else
copycolor(ar.rcoef, hp->acoef);
if (rayorigin(&ar, AMBIENT, hp->rp, ar.rcoef) < 0)
return(0);
if (ambacc > FTINY) {
multcolor(ar.rcoef, hp->acoef);
scalecolor(ar.rcoef, 1./AVGREFL);
}
hlist[0] = hp->rp->rno;
hlist[1] = j;
hlist[2] = i;
multisamp(spt, 2, urand(ilhash(hlist,3)+n));
resample:
SDsquare2disk(spt, (j+spt[1])/hp->ns, (i+spt[0])/hp->ns);
zd = sqrt(1. - spt[0]*spt[0] - spt[1]*spt[1]);
for (ii = 3; ii--; )
ar.rdir[ii] = spt[0]*hp->ux[ii] +
spt[1]*hp->uy[ii] +
zd*hp->rp->ron[ii];
checknorm(ar.rdir);
/* avoid coincident samples */
if (!n && ambcollision(hp, i, j, ar.rdir)) {
spt[0] = frandom(); spt[1] = frandom();
goto resample; /* reject this sample */
}
dimlist[ndims++] = AI(hp,i,j) + 90171;
rayvalue(&ar); /* evaluate ray */
ndims--;
zd = raydistance(&ar);
if (zd <= FTINY)
return(0); /* should never happen */
multcolor(ar.rcol, ar.rcoef); /* apply coefficient */
if (zd*ap->d < 1.0) /* new/closer distance? */
ap->d = 1.0/zd;
if (!n) { /* record first vertex & value */
if (zd > 10.0*thescene.cusize + 1000.)
zd = 10.0*thescene.cusize + 1000.;
VSUM(ap->p, ar.rorg, ar.rdir, zd);
copycolor(ap->v, ar.rcol);
} else { /* else update recorded value */
hp->acol[RED] -= colval(ap->v,RED);
hp->acol[GRN] -= colval(ap->v,GRN);
hp->acol[BLU] -= colval(ap->v,BLU);
zd = 1.0/(double)(n+1);
scalecolor(ar.rcol, zd);
zd *= (double)n;
scalecolor(ap->v, zd);
addcolor(ap->v, ar.rcol);
}
addcolor(hp->acol, ap->v); /* add to our sum */
return(1);
}
int
m_dielectric( /* color a ray which hit a dielectric interface */
OBJREC *m,
RAY *r
)
{
double cos1, cos2, nratio;
COLOR ctrans;
COLOR talb;
int hastexture;
int flatsurface;
double refl, trans;
FVECT dnorm;
double d1, d2;
RAY p;
int i;
/* PMAP: skip refracted shadow or ambient ray if accounted for in
photon map */
if (shadowRayInPmap(r) || ambRayInPmap(r))
return(1);
if (m->oargs.nfargs != (m->otype==MAT_DIELECTRIC ? 5 : 8))
objerror(m, USER, "bad arguments");
raytexture(r, m->omod); /* get modifiers */
if ( (hastexture = DOT(r->pert,r->pert) > FTINY*FTINY) )
cos1 = raynormal(dnorm, r); /* perturb normal */
else {
VCOPY(dnorm, r->ron);
cos1 = r->rod;
}
flatsurface = r->ro != NULL && isflat(r->ro->otype) &&
!hastexture | (r->crtype & AMBIENT);
/* index of refraction */
if (m->otype == MAT_DIELECTRIC)
nratio = m->oargs.farg[3] + m->oargs.farg[4]/MLAMBDA;
else
nratio = m->oargs.farg[3] / m->oargs.farg[7];
if (cos1 < 0.0) { /* inside */
hastexture = -hastexture;
cos1 = -cos1;
dnorm[0] = -dnorm[0];
dnorm[1] = -dnorm[1];
dnorm[2] = -dnorm[2];
setcolor(r->cext, -mylog(m->oargs.farg[0]*colval(r->pcol,RED)),
-mylog(m->oargs.farg[1]*colval(r->pcol,GRN)),
-mylog(m->oargs.farg[2]*colval(r->pcol,BLU)));
setcolor(r->albedo, 0., 0., 0.);
r->gecc = 0.;
if (m->otype == MAT_INTERFACE) {
setcolor(ctrans,
-mylog(m->oargs.farg[4]*colval(r->pcol,RED)),
-mylog(m->oargs.farg[5]*colval(r->pcol,GRN)),
-mylog(m->oargs.farg[6]*colval(r->pcol,BLU)));
setcolor(talb, 0., 0., 0.);
} else {
copycolor(ctrans, cextinction);
copycolor(talb, salbedo);
}
} else { /* outside */
nratio = 1.0 / nratio;
setcolor(ctrans, -mylog(m->oargs.farg[0]*colval(r->pcol,RED)),
-mylog(m->oargs.farg[1]*colval(r->pcol,GRN)),
-mylog(m->oargs.farg[2]*colval(r->pcol,BLU)));
setcolor(talb, 0., 0., 0.);
if (m->otype == MAT_INTERFACE) {
setcolor(r->cext,
-mylog(m->oargs.farg[4]*colval(r->pcol,RED)),
-mylog(m->oargs.farg[5]*colval(r->pcol,GRN)),
-mylog(m->oargs.farg[6]*colval(r->pcol,BLU)));
setcolor(r->albedo, 0., 0., 0.);
r->gecc = 0.;
}
}
d2 = 1.0 - nratio*nratio*(1.0 - cos1*cos1); /* compute cos theta2 */
if (d2 < FTINY) /* total reflection */
refl = 1.0;
else { /* refraction occurs */
/* compute Fresnel's equations */
cos2 = sqrt(d2);
d1 = cos1;
d2 = nratio*cos2;
d1 = (d1 - d2) / (d1 + d2);
refl = d1 * d1;
d1 = 1.0 / cos1;
d2 = nratio / cos2;
d1 = (d1 - d2) / (d1 + d2);
refl += d1 * d1;
refl *= 0.5;
trans = 1.0 - refl;
trans *= nratio*nratio; /* solid angle ratio */
setcolor(p.rcoef, trans, trans, trans);
if (rayorigin(&p, REFRACTED, r, p.rcoef) == 0) {
/* compute refracted ray */
d1 = nratio*cos1 - cos2;
for (i = 0; i < 3; i++)
p.rdir[i] = nratio*r->rdir[i] + d1*dnorm[i];
/* accidental reflection? */
if (hastexture &&
DOT(p.rdir,r->ron)*hastexture >= -FTINY) {
d1 *= (double)hastexture;
for (i = 0; i < 3; i++) /* ignore texture */
p.rdir[i] = nratio*r->rdir[i] +
d1*r->ron[i];
normalize(p.rdir); /* not exact */
} else
checknorm(p.rdir);
#ifdef DISPERSE
if (m->otype != MAT_DIELECTRIC
|| r->rod > 0.0
|| r->crtype & SHADOW
|| !directvis
|| m->oargs.farg[4] == 0.0
|| !disperse(m, r, p.rdir,
trans, ctrans, talb))
#endif
{
copycolor(p.cext, ctrans);
copycolor(p.albedo, talb);
rayvalue(&p);
multcolor(p.rcol, p.rcoef);
addcolor(r->rcol, p.rcol);
/* virtual distance */
if (flatsurface ||
(1.-FTINY <= nratio) &
(nratio <= 1.+FTINY))
r->rxt = r->rot + raydistance(&p);
}
}
}
setcolor(p.rcoef, refl, refl, refl);
if (!(r->crtype & SHADOW) &&
rayorigin(&p, REFLECTED, r, p.rcoef) == 0) {
/* compute reflected ray */
VSUM(p.rdir, r->rdir, dnorm, 2.*cos1);
/* accidental penetration? */
if (hastexture && DOT(p.rdir,r->ron)*hastexture <= FTINY)
VSUM(p.rdir, r->rdir, r->ron, 2.*r->rod);
checknorm(p.rdir);
rayvalue(&p); /* reflected ray value */
multcolor(p.rcol, p.rcoef); /* color contribution */
copycolor(r->mcol, p.rcol);
addcolor(r->rcol, p.rcol);
/* virtual distance */
r->rmt = r->rot;
if (flatsurface)
r->rmt += raydistance(&p);
}
/* rayvalue() computes absorption */
return(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--;
}
int
m_brdf( /* color a ray that hit a BRDTfunc material */
OBJREC *m,
RAY *r
)
{
int hitfront = 1;
BRDFDAT nd;
RAY sr;
double mirtest=0, mirdist=0;
double transtest=0, transdist=0;
int hasrefl, hastrans;
int hastexture;
COLOR ctmp;
FVECT vtmp;
double d;
MFUNC *mf;
int i;
/* check arguments */
if ((m->oargs.nsargs < 10) | (m->oargs.nfargs < 9))
objerror(m, USER, "bad # arguments");
nd.mp = m;
nd.pr = r;
/* dummy values */
nd.rspec = nd.tspec = 1.0;
nd.trans = 0.5;
/* diffuse reflectance */
if (r->rod > 0.0)
setcolor(nd.rdiff, m->oargs.farg[0],
m->oargs.farg[1],
m->oargs.farg[2]);
else
setcolor(nd.rdiff, m->oargs.farg[3],
m->oargs.farg[4],
m->oargs.farg[5]);
/* diffuse transmittance */
setcolor(nd.tdiff, m->oargs.farg[6],
m->oargs.farg[7],
m->oargs.farg[8]);
/* get modifiers */
raytexture(r, m->omod);
hastexture = DOT(r->pert,r->pert) > FTINY*FTINY;
if (hastexture) { /* perturb normal */
nd.pdot = raynormal(nd.pnorm, r);
} else {
VCOPY(nd.pnorm, r->ron);
nd.pdot = r->rod;
}
if (r->rod < 0.0) { /* orient perturbed values */
nd.pdot = -nd.pdot;
for (i = 0; i < 3; i++) {
nd.pnorm[i] = -nd.pnorm[i];
r->pert[i] = -r->pert[i];
}
hitfront = 0;
}
copycolor(nd.mcolor, r->pcol); /* get pattern color */
multcolor(nd.rdiff, nd.mcolor); /* modify diffuse values */
multcolor(nd.tdiff, nd.mcolor);
hasrefl = bright(nd.rdiff) > FTINY;
hastrans = bright(nd.tdiff) > FTINY;
/* load cal file */
nd.dp = NULL;
mf = getfunc(m, 9, 0x3f, 0);
/* compute transmitted ray */
setbrdfunc(&nd);
errno = 0;
setcolor(ctmp, evalue(mf->ep[3]),
evalue(mf->ep[4]),
evalue(mf->ep[5]));
if ((errno == EDOM) | (errno == ERANGE))
objerror(m, WARNING, "compute error");
else if (rayorigin(&sr, TRANS, r, ctmp) == 0) {
if (!(r->crtype & SHADOW) && hastexture) {
/* perturb direction */
VSUM(sr.rdir, r->rdir, r->pert, -.75);
if (normalize(sr.rdir) == 0.0) {
objerror(m, WARNING, "illegal perturbation");
VCOPY(sr.rdir, r->rdir);
}
} else {
VCOPY(sr.rdir, r->rdir);
}
rayvalue(&sr);
multcolor(sr.rcol, sr.rcoef);
addcolor(r->rcol, sr.rcol);
if (!hastexture) {
transtest = 2.0*bright(sr.rcol);
transdist = r->rot + sr.rt;
}
}
if (r->crtype & SHADOW) /* the rest is shadow */
return(1);
/* compute reflected ray */
setbrdfunc(&nd);
errno = 0;
setcolor(ctmp, evalue(mf->ep[0]),
evalue(mf->ep[1]),
evalue(mf->ep[2]));
if ((errno == EDOM) | (errno == ERANGE))
objerror(m, WARNING, "compute error");
else if (rayorigin(&sr, REFLECTED, r, ctmp) == 0) {
VSUM(sr.rdir, r->rdir, nd.pnorm, 2.*nd.pdot);
checknorm(sr.rdir);
rayvalue(&sr);
multcolor(sr.rcol, sr.rcoef);
addcolor(r->rcol, sr.rcol);
if (!hastexture && r->ro != NULL && isflat(r->ro->otype)) {
mirtest = 2.0*bright(sr.rcol);
mirdist = r->rot + sr.rt;
}
}
/* compute ambient */
if (hasrefl) {
if (!hitfront)
flipsurface(r);
copycolor(ctmp, nd.rdiff);
multambient(ctmp, r, nd.pnorm);
addcolor(r->rcol, ctmp); /* add to returned color */
if (!hitfront)
flipsurface(r);
}
if (hastrans) { /* from other side */
if (hitfront)
flipsurface(r);
vtmp[0] = -nd.pnorm[0];
vtmp[1] = -nd.pnorm[1];
vtmp[2] = -nd.pnorm[2];
copycolor(ctmp, nd.tdiff);
multambient(ctmp, r, vtmp);
addcolor(r->rcol, ctmp);
if (hitfront)
flipsurface(r);
}
if (hasrefl | hastrans || m->oargs.sarg[6][0] != '0')
direct(r, dirbrdf, &nd); /* add direct component */
d = bright(r->rcol); /* set effective distance */
if (transtest > d)
r->rt = transdist;
else if (mirtest > d)
r->rt = mirdist;
return(1);
}
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--;
}
}
