extern int
raymixture( /* mix modifiers */
RAY *r,
OBJECT fore,
OBJECT back,
double coef
)
{
RAY fr, br;
int foremat, backmat;
int i;
/* bound coefficient */
if (coef > 1.0)
coef = 1.0;
else if (coef < 0.0)
coef = 0.0;
/* compute foreground and background */
foremat = backmat = 0;
/* foreground */
fr = *r;
if (coef > FTINY) {
fr.rweight *= coef;
scalecolor(fr.rcoef, coef);
foremat = rayshade(&fr, fore);
}
/* background */
br = *r;
if (coef < 1.0-FTINY) {
br.rweight *= 1.0-coef;
scalecolor(br.rcoef, 1.0-coef);
backmat = rayshade(&br, back);
}
/* check for transparency */
if (backmat ^ foremat) {
if (backmat && coef > FTINY)
raytrans(&fr);
else if (foremat && coef < 1.0-FTINY)
raytrans(&br);
}
/* mix perturbations */
for (i = 0; i < 3; i++)
r->pert[i] = coef*fr.pert[i] + (1.0-coef)*br.pert[i];
/* mix pattern colors */
scalecolor(fr.pcol, coef);
scalecolor(br.pcol, 1.0-coef);
copycolor(r->pcol, fr.pcol);
addcolor(r->pcol, br.pcol);
/* return value tells if material */
if (!foremat & !backmat)
return(0);
/* mix returned ray values */
scalecolor(fr.rcol, coef);
scalecolor(br.rcol, 1.0-coef);
copycolor(r->rcol, fr.rcol);
addcolor(r->rcol, br.rcol);
r->rt = bright(fr.rcol) > bright(br.rcol) ? fr.rt : br.rt;
return(1);
}
extern int
rayshade( /* shade ray r with material mod */
RAY *r,
int mod
)
{
OBJREC *m;
r->rt = r->rot; /* set effective ray length */
for ( ; mod != OVOID; mod = m->omod) {
m = objptr(mod);
/****** unnecessary test since modifier() is always called
if (!ismodifier(m->otype)) {
sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
error(USER, errmsg);
}
******/
/* hack for irradiance calculation */
if (do_irrad && !(r->crtype & ~(PRIMARY|TRANS)) &&
m->otype != MAT_CLIP &&
(ofun[m->otype].flags & (T_M|T_X))) {
if (irr_ignore(m->otype)) {
raytrans(r);
return(1);
}
if (!islight(m->otype))
m = &Lamb;
}
if ((*ofun[m->otype].funp)(m, r))
return(1); /* materials call raytexture() */
}
return(0); /* no material! */
}
extern void
raycont( /* check for clipped object and continue */
RAY *r
)
{
if ((r->clipset != NULL && inset(r->clipset, r->ro->omod)) ||
!rayshade(r, r->ro->omod))
raytrans(r);
}
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_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);
}
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);
}