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);
}
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);
}
int
m_ashikhmin( /* shade ray that hit something anisotropic */
OBJREC *m,
RAY *r
)
{
ASHIKDAT nd;
COLOR ctmp;
double fres;
int i;
/* easy shadow test */
if (r->crtype & SHADOW)
return(1);
if (m->oargs.nfargs != 8)
objerror(m, USER, "bad number of real arguments");
/* check for back side */
if (r->rod < 0.0) {
if (!backvis) {
raytrans(r);
return(1);
}
raytexture(r, m->omod);
flipsurface(r); /* reorient if backvis */
} else
raytexture(r, m->omod);
/* get material color */
nd.mp = m;
nd.rp = r;
setcolor(nd.mcolor, m->oargs.farg[0],
m->oargs.farg[1],
m->oargs.farg[2]);
setcolor(nd.scolor, m->oargs.farg[3],
m->oargs.farg[4],
m->oargs.farg[5]);
/* get specular power */
nd.specfl = 0;
nd.u_power = m->oargs.farg[6];
nd.v_power = m->oargs.farg[7];
nd.pdot = raynormal(nd.pnorm, r); /* perturb normal */
if (nd.pdot < .001)
nd.pdot = .001; /* non-zero for dirashik() */
multcolor(nd.mcolor, r->pcol); /* modify diffuse color */
if (bright(nd.scolor) > FTINY) { /* adjust specular color */
nd.specfl |= SPA_REFL;
/* check threshold */
if (specthresh >= bright(nd.scolor)-FTINY)
nd.specfl |= SPA_RBLT;
fres = schlick_fres(nd.pdot); /* Schick's Fresnel approx */
for (i = 0; i < 3; i++)
colval(nd.scolor,i) += (1.-colval(nd.scolor,i))*fres;
}
if (r->ro != NULL && isflat(r->ro->otype))
nd.specfl |= SPA_FLAT;
/* set up coordinates */
getacoords_as(&nd);
/* specular sampling? */
if ((nd.specfl & (SPA_REFL|SPA_RBLT)) == SPA_REFL)
ashiksamp(&nd);
/* diffuse interreflection */
if (bright(nd.mcolor) > FTINY) {
copycolor(ctmp, nd.mcolor); /* modified by material color */
if (nd.specfl & SPA_RBLT) /* add in specular as well? */
addcolor(ctmp, nd.scolor);
multambient(ctmp, r, nd.pnorm);
addcolor(r->rcol, ctmp); /* add to returned color */
}
direct(r, dirashik, &nd); /* add direct component */
return(1);
}
static int
redirect( /* compute n'th ray redirection */
OBJREC *m,
RAY *r,
int n
)
{
MFUNC *mf;
EPNODE **va;
FVECT nsdir;
RAY nr;
double coef;
int j;
/* set up function */
mf = getdfunc(m);
setfunc(m, r);
/* assign direction variable */
if (r->rsrc >= 0) {
SRCREC *sp = source + source[r->rsrc].sa.sv.sn;
if (sp->sflags & SDISTANT)
VCOPY(nsdir, sp->sloc);
else {
for (j = 0; j < 3; j++)
nsdir[j] = sp->sloc[j] - r->rop[j];
normalize(nsdir);
}
multv3(nsdir, nsdir, funcxf.xfm);
varset("DxA", '=', nsdir[0]/funcxf.sca);
varset("DyA", '=', nsdir[1]/funcxf.sca);
varset("DzA", '=', nsdir[2]/funcxf.sca);
} else {
varset("DxA", '=', 0.0);
varset("DyA", '=', 0.0);
varset("DzA", '=', 0.0);
}
/* compute coefficient */
errno = 0;
va = mf->ep + 4*n;
coef = evalue(va[0]);
if ((errno == EDOM) | (errno == ERANGE))
goto computerr;
setcolor(nr.rcoef, coef, coef, coef);
if (rayorigin(&nr, TRANS, r, nr.rcoef) < 0)
return(0);
va++; /* compute direction */
for (j = 0; j < 3; j++) {
nr.rdir[j] = evalue(va[j]);
if (errno == EDOM || errno == ERANGE)
goto computerr;
}
if (mf->fxp != &unitxf)
multv3(nr.rdir, nr.rdir, mf->fxp->xfm);
if (r->rox != NULL)
multv3(nr.rdir, nr.rdir, r->rox->f.xfm);
if (normalize(nr.rdir) == 0.0)
goto computerr;
/* compute value */
if (r->rsrc >= 0)
nr.rsrc = source[r->rsrc].sa.sv.sn;
rayvalue(&nr);
multcolor(nr.rcol, nr.rcoef);
addcolor(r->rcol, nr.rcol);
if (r->ro != NULL && isflat(r->ro->otype))
r->rt = r->rot + nr.rt;
return(1);
computerr:
objerror(m, WARNING, "compute error");
return(-1);
}
int
m_aniso( /* shade ray that hit something anisotropic */
OBJREC *m,
RAY *r
)
{
ANISODAT nd;
COLOR ctmp;
int i;
/* easy shadow test */
if (r->crtype & SHADOW)
return(1);
if (m->oargs.nfargs != (m->otype == MAT_TRANS2 ? 8 : 6))
objerror(m, USER, "bad number of real arguments");
/* check for back side */
if (r->rod < 0.0) {
if (!backvis) {
raytrans(r);
return(1);
}
raytexture(r, m->omod);
flipsurface(r); /* reorient if backvis */
} else
raytexture(r, m->omod);
/* get material color */
nd.mp = m;
nd.rp = r;
setcolor(nd.mcolor, m->oargs.farg[0],
m->oargs.farg[1],
m->oargs.farg[2]);
/* get roughness */
nd.specfl = 0;
nd.u_alpha = m->oargs.farg[4];
nd.v_alpha = m->oargs.farg[5];
if ((nd.u_alpha <= FTINY) | (nd.v_alpha <= FTINY))
objerror(m, USER, "roughness too small");
nd.pdot = raynormal(nd.pnorm, r); /* perturb normal */
if (nd.pdot < .001)
nd.pdot = .001; /* non-zero for diraniso() */
multcolor(nd.mcolor, r->pcol); /* modify material color */
/* get specular component */
if ((nd.rspec = m->oargs.farg[3]) > FTINY) {
nd.specfl |= SP_REFL;
/* compute specular color */
if (m->otype == MAT_METAL2)
copycolor(nd.scolor, nd.mcolor);
else
setcolor(nd.scolor, 1.0, 1.0, 1.0);
scalecolor(nd.scolor, nd.rspec);
/* check threshold */
if (specthresh >= nd.rspec-FTINY)
nd.specfl |= SP_RBLT;
/* compute refl. direction */
VSUM(nd.vrefl, r->rdir, nd.pnorm, 2.0*nd.pdot);
if (DOT(nd.vrefl, r->ron) <= FTINY) /* penetration? */
VSUM(nd.vrefl, r->rdir, r->ron, 2.0*r->rod);
}
/* compute transmission */
if (m->otype == MAT_TRANS2) {
nd.trans = m->oargs.farg[6]*(1.0 - nd.rspec);
nd.tspec = nd.trans * m->oargs.farg[7];
nd.tdiff = nd.trans - nd.tspec;
if (nd.tspec > FTINY) {
nd.specfl |= SP_TRAN;
/* check threshold */
if (specthresh >= nd.tspec-FTINY)
nd.specfl |= SP_TBLT;
if (DOT(r->pert,r->pert) <= FTINY*FTINY) {
VCOPY(nd.prdir, r->rdir);
} else {
for (i = 0; i < 3; i++) /* perturb */
nd.prdir[i] = r->rdir[i] - r->pert[i];
if (DOT(nd.prdir, r->ron) < -FTINY)
normalize(nd.prdir); /* OK */
else
VCOPY(nd.prdir, r->rdir);
}
}
} else
nd.tdiff = nd.tspec = nd.trans = 0.0;
/* diffuse reflection */
nd.rdiff = 1.0 - nd.trans - nd.rspec;
if (r->ro != NULL && isflat(r->ro->otype))
nd.specfl |= SP_FLAT;
getacoords(&nd); /* set up coordinates */
if (nd.specfl & (SP_REFL|SP_TRAN))
agaussamp(&nd);
if (nd.rdiff > FTINY) { /* ambient from this side */
copycolor(ctmp, nd.mcolor); /* modified by material color */
scalecolor(ctmp, nd.rdiff);
if (nd.specfl & SP_RBLT) /* add in specular as well? */
addcolor(ctmp, nd.scolor);
multambient(ctmp, r, nd.pnorm);
addcolor(r->rcol, ctmp); /* add to returned color */
}
if (nd.tdiff > FTINY) { /* ambient from other side */
FVECT bnorm;
flipsurface(r);
bnorm[0] = -nd.pnorm[0];
bnorm[1] = -nd.pnorm[1];
bnorm[2] = -nd.pnorm[2];
copycolor(ctmp, nd.mcolor); /* modified by color */
if (nd.specfl & SP_TBLT)
scalecolor(ctmp, nd.trans);
else
scalecolor(ctmp, nd.tdiff);
multambient(ctmp, r, bnorm);
addcolor(r->rcol, ctmp);
flipsurface(r);
}
/* add direct component */
direct(r, diraniso, &nd);
return(1);
}