extern void
rayparticipate( /* compute ray medium participation */
RAY *r
)
{
COLOR ce, ca;
double re, ge, be;
if (intens(r->cext) <= 1./FHUGE)
return; /* no medium */
re = r->rot*colval(r->cext,RED);
ge = r->rot*colval(r->cext,GRN);
be = r->rot*colval(r->cext,BLU);
if (r->crtype & SHADOW) { /* no scattering for sources */
re *= 1. - colval(r->albedo,RED);
ge *= 1. - colval(r->albedo,GRN);
be *= 1. - colval(r->albedo,BLU);
}
setcolor(ce, re<=FTINY ? 1. : re>92. ? 0. : exp(-re),
ge<=FTINY ? 1. : ge>92. ? 0. : exp(-ge),
be<=FTINY ? 1. : be>92. ? 0. : exp(-be));
multcolor(r->rcol, ce); /* path extinction */
if (r->crtype & SHADOW || intens(r->albedo) <= FTINY)
return; /* no scattering */
setcolor(ca,
colval(r->albedo,RED)*colval(ambval,RED)*(1.-colval(ce,RED)),
colval(r->albedo,GRN)*colval(ambval,GRN)*(1.-colval(ce,GRN)),
colval(r->albedo,BLU)*colval(ambval,BLU)*(1.-colval(ce,BLU)));
addcolor(r->rcol, ca); /* ambient in scattering */
srcscatter(r); /* source in scattering */
}
extern void
pass2scan( /* process final pass scanline */
register COLOR *scan,
int y
)
{
int xmin, xmax;
register int x;
register HOTPIX *hp;
for (hp = head; hp != NULL; hp = hp->next) {
if (hp->slope > FTINY) {
xmin = (y - hp->y - 0.5)/hp->slope + hp->x;
xmax = (y - hp->y + 0.5)/hp->slope + hp->x;
} else if (hp->slope < -FTINY) {
xmin = (y - hp->y + 0.5)/hp->slope + hp->x;
xmax = (y - hp->y - 0.5)/hp->slope + hp->x;
} else if (y == hp->y) {
xmin = 0;
xmax = xres-1;
} else {
xmin = 1;
xmax = 0;
}
if (xmin < 0)
xmin = 0;
if (xmax >= xres)
xmax = xres-1;
for (x = xmin; x <= xmax; x++)
starpoint(scan[x], x, y, hp);
}
for (x = 0; x < xres; x++)
multcolor(scan[x], exposure);
}
static void
valtopix(void) /* convert values to a pixel file */
{
int dogamma;
register COLOR *scanln;
int y;
register int x;
scanln = (COLOR *)malloc(scanlen(&picres)*sizeof(COLOR));
if (scanln == NULL) {
fprintf(stderr, "%s: out of memory\n", progname);
quit(1);
}
dogamma = gamcor < .95 || gamcor > 1.05;
set_io();
for (y = 0; y < numscans(&picres); y++) {
for (x = 0; x < scanlen(&picres); x++) {
if (!dataonly) {
fscanf(fin, "%*d %*d");
if (fin2 != NULL) {
fscanf(fin2, "%*d %*d");
fscanf(fin3, "%*d %*d");
}
}
if ((*getval)(scanln[x]) < 0) {
fprintf(stderr, "%s: read error\n", progname);
quit(1);
}
if (dogamma)
setcolor(scanln[x],
pow(colval(scanln[x],RED), gamcor),
pow(colval(scanln[x],GRN), gamcor),
pow(colval(scanln[x],BLU), gamcor));
if (doexposure)
multcolor(scanln[x], exposure);
}
if (fwritescan(scanln, scanlen(&picres), stdout) < 0) {
fprintf(stderr, "%s: write error\n", progname);
quit(1);
}
}
free((void *)scanln);
}
static int
headline( /* check header line & echo if requested */
char *s,
void *p
)
{
char fmt[32];
double d;
COLOR ctmp;
if (isheadid(s)) /* header id */
return(0); /* don't echo */
if (formatval(fmt, s)) { /* check format */
if (globmatch(ourfmt, fmt)) {
wrongformat = 0;
strcpy(ourfmt, fmt);
} else
wrongformat = globmatch(PICFMT, fmt) ? 1 : -1;
return(0); /* don't echo */
}
if (isexpos(s)) { /* exposure */
d = exposval(s);
scalecolor(input[nfiles].expos, d);
} else if (iscolcor(s)) { /* color correction */
colcorval(ctmp, s);
multcolor(input[nfiles].expos, ctmp);
} else if (isaspect(s))
input[nfiles].pa *= aspectval(s);
else if (isview(s) && sscanview(&input[nfiles].vw, s) > 0)
gotview++;
if (echoheader) { /* echo line */
putchar('\t');
return(fputs(s, stdout));
}
return(0);
}
extern int
p_cfunc( /* compute color pattern */
OBJREC *m,
RAY *r
)
{
COLOR cval;
register MFUNC *mf;
if (m->oargs.nsargs < 4)
objerror(m, USER, "bad # arguments");
mf = getfunc(m, 3, 0x7, 0);
setfunc(m, r);
errno = 0;
setcolor(cval, evalue(mf->ep[0]),
evalue(mf->ep[1]),
evalue(mf->ep[2]));
if (errno == EDOM || errno == ERANGE) {
objerror(m, WARNING, "compute error");
return(0);
}
multcolor(r->pcol, cval);
return(0);
}
static void
advance(void) /* read in data for next scanline */
{
int ytarget;
register COLOR *st;
register int i, j;
for (ytarget = (ypos+.5)*ymax/yres; yscan > ytarget; yscan--)
for (i = 0; i < nfiles; i++) {
st = input[i].scan[WINSIZ-1];
for (j = WINSIZ-1; j > 0; j--) /* rotate window */
input[i].scan[j] = input[i].scan[j-1];
input[i].scan[0] = st;
if (yscan <= MIDSCN) /* hit bottom? */
continue;
if (freadscan(st, xmax, input[i].fp) < 0) { /* read */
eputs(input[i].name);
eputs(": read error\n");
quit(1);
}
for (j = 0; j < xmax; j++) /* adjust color */
multcolor(st[j], input[i].coef);
}
}
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 int
disperse( /* check light sources for dispersion */
OBJREC *m,
RAY *r,
FVECT vt,
double tr,
COLOR cet,
COLOR abt
)
{
RAY sray;
const RAY *entray;
FVECT v1, v2, n1, n2;
FVECT dv, v2Xdv;
double v2Xdvv2Xdv;
int success = 0;
SRCINDEX si;
FVECT vtmp1, vtmp2;
double dtmp1, dtmp2;
int l1, l2;
COLOR ctmp;
int i;
/*
* This routine computes dispersion to the first order using
* the following assumptions:
*
* 1) The dependency of the index of refraction on wavelength
* is approximated by Hartmann's equation with lambda0
* equal to zero.
* 2) The entry and exit locations are constant with respect
* to dispersion.
*
* The second assumption permits us to model dispersion without
* having to sample refracted directions. We assume that the
* geometry inside the material is constant, and concern ourselves
* only with the relationship between the entering and exiting ray.
* We compute the first derivatives of the entering and exiting
* refraction with respect to the index of refraction. This
* is then used in a first order Taylor series to determine the
* index of refraction necessary to send the exiting ray to each
* light source.
* If an exiting ray hits a light source within the refraction
* boundaries, we sum all the frequencies over the disc of the
* light source to determine the resulting color. A smaller light
* source will therefore exhibit a sharper spectrum.
*/
if (!(r->crtype & REFRACTED)) { /* ray started in material */
VCOPY(v1, r->rdir);
n1[0] = -r->rdir[0]; n1[1] = -r->rdir[1]; n1[2] = -r->rdir[2];
} else {
/* find entry point */
for (entray = r; entray->rtype != REFRACTED;
entray = entray->parent)
;
entray = entray->parent;
if (entray->crtype & REFRACTED) /* too difficult */
return(0);
VCOPY(v1, entray->rdir);
VCOPY(n1, entray->ron);
}
VCOPY(v2, vt); /* exiting ray */
VCOPY(n2, r->ron);
/* first order dispersion approx. */
dtmp1 = 1./DOT(n1, v1);
dtmp2 = 1./DOT(n2, v2);
for (i = 0; i < 3; i++)
dv[i] = v1[i] + v2[i] - n1[i]*dtmp1 - n2[i]*dtmp2;
if (DOT(dv, dv) <= FTINY) /* null effect */
return(0);
/* compute plane normal */
fcross(v2Xdv, v2, dv);
v2Xdvv2Xdv = DOT(v2Xdv, v2Xdv);
/* check sources */
initsrcindex(&si);
while (srcray(&sray, r, &si)) {
if (DOT(sray.rdir, v2) < MINCOS)
continue; /* bad source */
/* adjust source ray */
dtmp1 = DOT(v2Xdv, sray.rdir) / v2Xdvv2Xdv;
sray.rdir[0] -= dtmp1 * v2Xdv[0];
sray.rdir[1] -= dtmp1 * v2Xdv[1];
sray.rdir[2] -= dtmp1 * v2Xdv[2];
l1 = lambda(m, v2, dv, sray.rdir); /* mean lambda */
if (l1 > MAXLAMBDA || l1 < MINLAMBDA) /* not visible */
continue;
/* trace source ray */
copycolor(sray.cext, cet);
copycolor(sray.albedo, abt);
normalize(sray.rdir);
rayvalue(&sray);
if (bright(sray.rcol) <= FTINY) /* missed it */
continue;
/*
* Compute spectral sum over diameter of source.
* First find directions for rays going to opposite
* sides of source, then compute wavelengths for each.
*/
fcross(vtmp1, v2Xdv, sray.rdir);
dtmp1 = sqrt(si.dom / v2Xdvv2Xdv / PI);
/* compute first ray */
VSUM(vtmp2, sray.rdir, vtmp1, dtmp1);
l1 = lambda(m, v2, dv, vtmp2); /* first lambda */
if (l1 < 0)
continue;
/* compute second ray */
VSUM(vtmp2, sray.rdir, vtmp1, -dtmp1);
l2 = lambda(m, v2, dv, vtmp2); /* second lambda */
if (l2 < 0)
continue;
/* compute color from spectrum */
if (l1 < l2)
spec_rgb(ctmp, l1, l2);
else
spec_rgb(ctmp, l2, l1);
multcolor(ctmp, sray.rcol);
scalecolor(ctmp, tr);
addcolor(r->rcol, ctmp);
success++;
}
return(success);
}
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);
}
static void
pixtoval(void) /* convert picture to values */
{
register COLOR *scanln;
int dogamma;
COLOR lastc;
RREAL hv[2];
int startprim, endprim;
long startpos;
int y;
register int x;
scanln = (COLOR *)malloc(scanlen(&picres)*sizeof(COLOR));
if (scanln == NULL) {
fprintf(stderr, "%s: out of memory\n", progname);
quit(1);
}
dogamma = gamcor < .95 || gamcor > 1.05;
if (putprim == ALL && !interleave) {
startprim = RED; endprim = BLU;
startpos = ftell(fin);
} else {
startprim = putprim; endprim = putprim;
}
for (putprim = startprim; putprim <= endprim; putprim++) {
if (putprim != startprim && fseek(fin, startpos, 0)) {
fprintf(stderr, "%s: seek error on input file\n",
progname);
quit(1);
}
set_io();
setcolor(lastc, 0.0, 0.0, 0.0);
for (y = 0; y < numscans(&picres); y++) {
if (freadscan(scanln, scanlen(&picres), fin) < 0) {
fprintf(stderr, "%s: read error\n", progname);
quit(1);
}
for (x = 0; x < scanlen(&picres); x++) {
if (uniq) {
if ( colval(scanln[x],RED) ==
colval(lastc,RED) &&
colval(scanln[x],GRN) ==
colval(lastc,GRN) &&
colval(scanln[x],BLU) ==
colval(lastc,BLU) )
continue;
else
copycolor(lastc, scanln[x]);
}
if (doexposure)
multcolor(scanln[x], exposure);
if (dogamma)
setcolor(scanln[x],
pow(colval(scanln[x],RED), 1.0/gamcor),
pow(colval(scanln[x],GRN), 1.0/gamcor),
pow(colval(scanln[x],BLU), 1.0/gamcor));
if (!dataonly) {
pix2loc(hv, &picres, x, y);
printf("%7d %7d ",
(int)(hv[0]*picres.xr),
(int)(hv[1]*picres.yr));
}
if ((*putval)(scanln[x]) < 0) {
fprintf(stderr, "%s: write error\n",
progname);
quit(1);
}
}
}
}
free((void *)scanln);
}
static void
dirbrdf( /* compute source contribution */
COLOR cval, /* returned coefficient */
void *nnp, /* material data */
FVECT ldir, /* light source direction */
double omega /* light source size */
)
{
BRDFDAT *np = nnp;
double ldot;
double dtmp;
COLOR ctmp;
FVECT ldx;
static double vldx[5], pt[MAXDIM];
char **sa;
int i;
#define lddx (vldx+1)
setcolor(cval, 0.0, 0.0, 0.0);
ldot = DOT(np->pnorm, ldir);
if (ldot <= FTINY && ldot >= -FTINY)
return; /* too close to grazing */
if (ldot < 0.0 ? np->trans <= FTINY : np->trans >= 1.0-FTINY)
return; /* wrong side */
if (ldot > 0.0) {
/*
* Compute and add diffuse reflected component to returned
* color. The diffuse reflected component will always be
* modified by the color of the material.
*/
copycolor(ctmp, np->rdiff);
dtmp = ldot * omega / PI;
scalecolor(ctmp, dtmp);
addcolor(cval, ctmp);
} else {
/*
* Diffuse transmitted component.
*/
copycolor(ctmp, np->tdiff);
dtmp = -ldot * omega / PI;
scalecolor(ctmp, dtmp);
addcolor(cval, ctmp);
}
if (ldot > 0.0 ? np->rspec <= FTINY : np->tspec <= FTINY)
return; /* diffuse only */
/* set up function */
setbrdfunc(np);
sa = np->mp->oargs.sarg;
errno = 0;
/* transform light vector */
multv3(ldx, ldir, funcxf.xfm);
for (i = 0; i < 3; i++)
lddx[i] = ldx[i]/funcxf.sca;
lddx[3] = omega;
/* compute BRTDF */
if (np->mp->otype == MAT_BRTDF) {
if (sa[6][0] == '0') /* special case */
colval(ctmp,RED) = 0.0;
else
colval(ctmp,RED) = funvalue(sa[6], 4, lddx);
if (sa[7][0] == '0')
colval(ctmp,GRN) = 0.0;
else if (!strcmp(sa[7],sa[6]))
colval(ctmp,GRN) = colval(ctmp,RED);
else
colval(ctmp,GRN) = funvalue(sa[7], 4, lddx);
if (!strcmp(sa[8],sa[6]))
colval(ctmp,BLU) = colval(ctmp,RED);
else if (!strcmp(sa[8],sa[7]))
colval(ctmp,BLU) = colval(ctmp,GRN);
else
colval(ctmp,BLU) = funvalue(sa[8], 4, lddx);
dtmp = bright(ctmp);
} else if (np->dp == NULL) {
dtmp = funvalue(sa[0], 4, lddx);
setcolor(ctmp, dtmp, dtmp, dtmp);
} else {
for (i = 0; i < np->dp->nd; i++)
pt[i] = funvalue(sa[3+i], 4, lddx);
vldx[0] = datavalue(np->dp, pt);
dtmp = funvalue(sa[0], 5, vldx);
setcolor(ctmp, dtmp, dtmp, dtmp);
}
if ((errno == EDOM) | (errno == ERANGE)) {
objerror(np->mp, WARNING, "compute error");
return;
}
if (dtmp <= FTINY)
return;
if (ldot > 0.0) {
/*
* Compute reflected non-diffuse component.
*/
if ((np->mp->otype == MAT_MFUNC) | (np->mp->otype == MAT_MDATA))
multcolor(ctmp, np->mcolor);
dtmp = ldot * omega * np->rspec;
scalecolor(ctmp, dtmp);
addcolor(cval, ctmp);
} else {
/*
* Compute transmitted non-diffuse component.
*/
if ((np->mp->otype == MAT_TFUNC) | (np->mp->otype == MAT_TDATA))
multcolor(ctmp, np->mcolor);
dtmp = -ldot * omega * np->tspec;
scalecolor(ctmp, dtmp);
addcolor(cval, ctmp);
}
#undef lddx
}
int
m_brdf2( /* color a ray that hit a BRDF material */
OBJREC *m,
RAY *r
)
{
BRDFDAT nd;
COLOR ctmp;
FVECT vtmp;
double dtmp;
/* always a shadow */
if (r->crtype & SHADOW)
return(1);
/* check arguments */
if ((m->oargs.nsargs < (hasdata(m->otype)?4:2)) | (m->oargs.nfargs <
((m->otype==MAT_TFUNC)|(m->otype==MAT_TDATA)?6:4)))
objerror(m, USER, "bad # 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);
nd.mp = m;
nd.pr = r;
/* get material color */
setcolor(nd.mcolor, m->oargs.farg[0],
m->oargs.farg[1],
m->oargs.farg[2]);
/* get specular component */
nd.rspec = m->oargs.farg[3];
/* compute transmittance */
if ((m->otype == MAT_TFUNC) | (m->otype == MAT_TDATA)) {
nd.trans = m->oargs.farg[4]*(1.0 - nd.rspec);
nd.tspec = nd.trans * m->oargs.farg[5];
dtmp = nd.trans - nd.tspec;
setcolor(nd.tdiff, dtmp, dtmp, dtmp);
} else {
nd.tspec = nd.trans = 0.0;
setcolor(nd.tdiff, 0.0, 0.0, 0.0);
}
/* compute reflectance */
dtmp = 1.0 - nd.trans - nd.rspec;
setcolor(nd.rdiff, dtmp, dtmp, dtmp);
nd.pdot = raynormal(nd.pnorm, r); /* perturb normal */
multcolor(nd.mcolor, r->pcol); /* modify material color */
multcolor(nd.rdiff, nd.mcolor);
multcolor(nd.tdiff, nd.mcolor);
/* load auxiliary files */
if (hasdata(m->otype)) {
nd.dp = getdata(m->oargs.sarg[1]);
getfunc(m, 2, 0, 0);
} else {
nd.dp = NULL;
getfunc(m, 1, 0, 0);
}
/* compute ambient */
if (nd.trans < 1.0-FTINY) {
copycolor(ctmp, nd.mcolor); /* modified by material color */
scalecolor(ctmp, 1.0-nd.trans);
multambient(ctmp, r, nd.pnorm);
addcolor(r->rcol, ctmp); /* add to returned color */
}
if (nd.trans > FTINY) { /* from other side */
flipsurface(r);
vtmp[0] = -nd.pnorm[0];
vtmp[1] = -nd.pnorm[1];
vtmp[2] = -nd.pnorm[2];
copycolor(ctmp, nd.mcolor);
scalecolor(ctmp, nd.trans);
multambient(ctmp, r, vtmp);
addcolor(r->rcol, ctmp);
flipsurface(r);
}
/* add direct component */
direct(r, dirbrdf, &nd);
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);
}
extern void
multambient( /* compute ambient component & multiply by coef. */
COLOR aval,
RAY *r,
FVECT nrm
)
{
static int rdepth = 0; /* ambient recursion */
COLOR acol;
double d, l;
if (ambdiv <= 0) /* no ambient calculation */
goto dumbamb;
/* check number of bounces */
if (rdepth >= ambounce)
goto dumbamb;
/* check ambient list */
if (ambincl != -1 && r->ro != NULL &&
ambincl != inset(ambset, r->ro->omod))
goto dumbamb;
if (ambacc <= FTINY) { /* no ambient storage */
copycolor(acol, aval);
rdepth++;
d = doambient(acol, r, r->rweight, NULL, NULL);
rdepth--;
if (d <= FTINY)
goto dumbamb;
copycolor(aval, acol);
return;
}
if (tracktime) /* sort to minimize thrashing */
sortambvals(0);
/* interpolate ambient value */
setcolor(acol, 0.0, 0.0, 0.0);
d = sumambient(acol, r, nrm, rdepth,
&atrunk, thescene.cuorg, thescene.cusize);
if (d > FTINY) {
d = 1.0/d;
scalecolor(acol, d);
multcolor(aval, acol);
return;
}
rdepth++; /* need to cache new value */
d = makeambient(acol, r, nrm, rdepth-1);
rdepth--;
if (d > FTINY) {
multcolor(aval, acol); /* got new value */
return;
}
dumbamb: /* return global value */
if ((ambvwt <= 0) | (navsum == 0)) {
multcolor(aval, ambval);
return;
}
l = bright(ambval); /* average in computations */
if (l > FTINY) {
d = (log(l)*(double)ambvwt + avsum) /
(double)(ambvwt + navsum);
d = exp(d) / l;
scalecolor(aval, d);
multcolor(aval, ambval); /* apply color of ambval */
} else {
d = exp( avsum / (double)navsum );
scalecolor(aval, d); /* neutral color */
}
}
extern void
direct( /* add direct component */
RAY *r, /* ray that hit surface */
srcdirf_t *f, /* direct component coefficient function */
void *p /* data for f */
)
{
register int sn;
register CONTRIB *scp;
SRCINDEX si;
int nshadcheck, ncnts;
int nhits;
double prob, ourthresh, hwt;
RAY sr;
/* 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;
/* compute coefficient */
(*f)(scp->coef, p, sr.rdir, si.dom);
cntord[sn].brt = intens(scp->coef);
if (cntord[sn].brt <= 0.0)
continue;
#if SHADCACHE
/* check shadow cache */
if (si.np == 1 && srcblocked(&sr)) {
cntord[sn].brt = 0.0;
continue;
}
#endif
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 */
register 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+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++;
}
int
m_mist( /* process a ray entering or leaving some mist */
OBJREC *m,
RAY *r
)
{
RAY p;
int *myslist = NULL;
int newslist[MAXSLIST+1];
COLOR mext;
double re, ge, be;
int i, j;
/* check arguments */
if (m->oargs.nfargs > 7)
objerror(m, USER, "bad arguments");
/* get source indices */
if (m->oargs.nsargs > 0 && (myslist = (int *)m->os) == NULL) {
if (m->oargs.nsargs > MAXSLIST)
objerror(m, INTERNAL, "too many sources in list");
myslist = (int *)malloc((m->oargs.nsargs+1)*sizeof(int));
if (myslist == NULL)
goto memerr;
myslist[0] = 0; /* size is first in list */
for (j = 0; j < m->oargs.nsargs; j++) {
i = nsources; /* look up each source id */
while (i--)
if (srcmatch(source+i, m->oargs.sarg[j]))
break;
if (i < 0) {
sprintf(errmsg, "unknown source \"%s\"",
m->oargs.sarg[j]);
objerror(m, WARNING, errmsg);
} else if (inslist(myslist, i)) {
sprintf(errmsg, "duplicate source \"%s\"",
m->oargs.sarg[j]);
objerror(m, WARNING, errmsg);
} else
myslist[++myslist[0]] = i;
}
m->os = (char *)myslist;
}
if (m->oargs.nfargs > 2) { /* compute extinction */
setcolor(mext, m->oargs.farg[0], m->oargs.farg[1],
m->oargs.farg[2]);
raytexture(r, m->omod); /* get modifiers */
multcolor(mext, r->pcol);
} else
setcolor(mext, 0., 0., 0.);
/* start transmitted ray */
if (rayorigin(&p, TRANS, r, NULL) < 0)
return(1);
VCOPY(p.rdir, r->rdir);
p.slights = newslist;
if (r->slights != NULL) /* copy old list if one */
for (j = r->slights[0]; j >= 0; j--)
p.slights[j] = r->slights[j];
else
p.slights[0] = 0;
if (r->rod > 0.) { /* entering ray */
addcolor(p.cext, mext);
if (m->oargs.nfargs > 5)
setcolor(p.albedo, m->oargs.farg[3],
m->oargs.farg[4], m->oargs.farg[5]);
if (m->oargs.nfargs > 6)
p.gecc = m->oargs.farg[6];
add2slist(&p, myslist); /* add to list */
} else { /* leaving ray */
if (myslist != NULL) { /* delete from list */
for (j = myslist[0]; j > 0; j--)
if ( (i = inslist(p.slights, myslist[j])) )
p.slights[i] = -1;
for (i = 0, j = 1; j <= p.slights[0]; j++)
if (p.slights[j] != -1)
p.slights[++i] = p.slights[j];
if (p.slights[0] - i < myslist[0]) { /* fix old */
addcolor(r->cext, mext);
if (m->oargs.nfargs > 5)
setcolor(r->albedo, m->oargs.farg[3],
m->oargs.farg[4], m->oargs.farg[5]);
if (m->oargs.nfargs > 6)
r->gecc = m->oargs.farg[6];
add2slist(r, myslist);
}
p.slights[0] = i;
}
if ((re = colval(r->cext,RED) - colval(mext,RED)) <
colval(cextinction,RED))
re = colval(cextinction,RED);
if ((ge = colval(r->cext,GRN) - colval(mext,GRN)) <
colval(cextinction,GRN))
ge = colval(cextinction,GRN);
if ((be = colval(r->cext,BLU) - colval(mext,BLU)) <
colval(cextinction,BLU))
be = colval(cextinction,BLU);
setcolor(p.cext, re, ge, be);
if (m->oargs.nfargs > 5)
copycolor(p.albedo, salbedo);
if (m->oargs.nfargs > 6)
p.gecc = seccg;
}
rayvalue(&p); /* calls rayparticipate() */
copycolor(r->rcol, p.rcol); /* return value */
r->rt = r->rot + p.rt;
return(1);
memerr:
error(SYSTEM, "out of memory in m_mist");
return 0; /* pro forma return */
}
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--;
}
}
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_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
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);
}
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);
}
