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extern double specthresh; /* specular sampling threshold */ |
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extern double specjitter; /* specular sampling jitter */ |
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|
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static gaussamp(); |
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|
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/* |
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* This routine uses portions of the reflection |
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* model described by Cook and Torrance. |
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* The computation of specular components has been simplified by |
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* numerous approximations and ommisions to improve speed. |
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* This routine implements the isotropic Gaussian |
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* model described by Ward in Siggraph `92 article. |
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* We orient the surface towards the incoming ray, so a single |
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* surface can be used to represent an infinitely thin object. |
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* |
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* red grn blu rspec rough trans tspec |
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*/ |
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|
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#define BSPEC(m) (6.0) /* specularity parameter b */ |
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|
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/* specularity flags */ |
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#define SP_REFL 01 /* has reflected specular component */ |
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#define SP_TRAN 02 /* has transmitted specular */ |
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double ldot; |
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double dtmp, d2; |
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FVECT vtmp; |
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register int i; |
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COLOR ctmp; |
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|
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setcolor(cval, 0.0, 0.0, 0.0); |
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/* + source if flat */ |
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if (np->specfl & SP_FLAT) |
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dtmp += omega/(4.0*PI); |
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/* delta */ |
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for (i = 0; i < 3; i++) |
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vtmp[i] = ldir[i] - np->rp->rdir[i]; |
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/* half vector */ |
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vtmp[0] = ldir[0] - np->rp->rdir[0]; |
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vtmp[1] = ldir[1] - np->rp->rdir[1]; |
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vtmp[2] = ldir[2] - np->rp->rdir[2]; |
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d2 = DOT(vtmp, np->pnorm); |
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d2 = 2.0 - 2.0*d2/sqrt(DOT(vtmp,vtmp)); |
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d2 *= d2; |
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d2 = (DOT(vtmp,vtmp) - d2) / d2; |
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/* gaussian */ |
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dtmp = exp(-d2/dtmp)/(4.*PI*dtmp); |
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/* worth using? */ |
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* is always modified by material color. |
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*/ |
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/* roughness + source */ |
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dtmp = np->alpha2/2.0 + omega/(2.0*PI); |
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> |
dtmp = np->alpha2 + omega/PI; |
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/* gaussian */ |
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< |
dtmp = exp((DOT(np->prdir,ldir)-1.)/dtmp)/(2.*PI)/dtmp; |
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> |
dtmp = exp((2.*DOT(np->prdir,ldir)-2.)/dtmp)/(PI*dtmp); |
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/* worth using? */ |
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if (dtmp > FTINY) { |
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copycolor(ctmp, np->mcolor); |
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< |
dtmp *= np->tspec * omega * sqrt(ldot/np->pdot); |
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> |
dtmp *= np->tspec * omega * sqrt(-ldot/np->pdot); |
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scalecolor(ctmp, dtmp); |
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addcolor(cval, ctmp); |
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} |
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{ |
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NORMDAT nd; |
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double transtest, transdist; |
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double dtmp; |
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COLOR ctmp; |
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register int i; |
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/* easy shadow test */ |
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if (r->crtype & SHADOW && m->otype != MAT_TRANS) |
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< |
return; |
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> |
return(1); |
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|
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if (m->oargs.nfargs != (m->otype == MAT_TRANS ? 7 : 5)) |
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objerror(m, USER, "bad number of arguments"); |
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nd.pdot = .001; /* non-zero for dirnorm() */ |
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multcolor(nd.mcolor, r->pcol); /* modify material color */ |
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transtest = 0; |
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+ |
transdist = r->rot; |
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/* get specular component */ |
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if ((nd.rspec = m->oargs.farg[3]) > FTINY) { |
| 189 |
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nd.specfl |= SP_REFL; |
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else |
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setcolor(nd.scolor, 1.0, 1.0, 1.0); |
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scalecolor(nd.scolor, nd.rspec); |
| 197 |
– |
/* improved model */ |
| 198 |
– |
dtmp = exp(-BSPEC(m)*nd.pdot); |
| 199 |
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for (i = 0; i < 3; i++) |
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– |
colval(nd.scolor,i) += (1.0-colval(nd.scolor,i))*dtmp; |
| 201 |
– |
nd.rspec += (1.0-nd.rspec)*dtmp; |
| 196 |
|
/* check threshold */ |
| 197 |
< |
if (!(nd.specfl & SP_PURE) && |
| 204 |
< |
specthresh > FTINY && |
| 205 |
< |
(specthresh >= 1.-FTINY || |
| 206 |
< |
specthresh + .05 - .1*frandom() > nd.rspec)) |
| 197 |
> |
if (!(nd.specfl & SP_PURE) && specthresh >= nd.rspec-FTINY) |
| 198 |
|
nd.specfl |= SP_RBLT; |
| 199 |
|
/* compute reflected ray */ |
| 200 |
|
for (i = 0; i < 3; i++) |
| 221 |
|
if (nd.tspec > FTINY) { |
| 222 |
|
nd.specfl |= SP_TRAN; |
| 223 |
|
/* check threshold */ |
| 224 |
< |
if (!(nd.specfl & SP_PURE) && specthresh > FTINY && |
| 225 |
< |
(specthresh >= 1.-FTINY || |
| 235 |
< |
specthresh + .05 - .1*frandom() > nd.tspec)) |
| 224 |
> |
if (!(nd.specfl & SP_PURE) && |
| 225 |
> |
specthresh >= nd.tspec-FTINY) |
| 226 |
|
nd.specfl |= SP_TBLT; |
| 227 |
|
if (r->crtype & SHADOW || |
| 228 |
|
DOT(r->pert,r->pert) <= FTINY*FTINY) { |
| 230 |
|
transtest = 2; |
| 231 |
|
} else { |
| 232 |
|
for (i = 0; i < 3; i++) /* perturb */ |
| 233 |
< |
nd.prdir[i] = r->rdir[i] - |
| 244 |
< |
0.5*r->pert[i]; |
| 233 |
> |
nd.prdir[i] = r->rdir[i] - r->pert[i]; |
| 234 |
|
if (DOT(nd.prdir, r->ron) < -FTINY) |
| 235 |
|
normalize(nd.prdir); /* OK */ |
| 236 |
|
else |
| 255 |
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transtest = 0; |
| 256 |
|
|
| 257 |
|
if (r->crtype & SHADOW) /* the rest is shadow */ |
| 258 |
< |
return; |
| 258 |
> |
return(1); |
| 259 |
|
/* diffuse reflection */ |
| 260 |
|
nd.rdiff = 1.0 - nd.trans - nd.rspec; |
| 261 |
|
|
| 262 |
|
if (nd.specfl & SP_PURE && nd.rdiff <= FTINY && nd.tdiff <= FTINY) |
| 263 |
< |
return; /* 100% pure specular */ |
| 263 |
> |
return(1); /* 100% pure specular */ |
| 264 |
|
|
| 265 |
|
if (r->ro != NULL && (r->ro->otype == OBJ_FACE || |
| 266 |
|
r->ro->otype == OBJ_RING)) |
| 294 |
|
/* check distance */ |
| 295 |
|
if (transtest > bright(r->rcol)) |
| 296 |
|
r->rt = transdist; |
| 297 |
+ |
|
| 298 |
+ |
return(1); |
| 299 |
|
} |
| 300 |
|
|
| 301 |
|
|
| 361 |
|
if (rv[1] <= FTINY) |
| 362 |
|
d = 1.0; |
| 363 |
|
else |
| 364 |
< |
d = sqrt( np->alpha2/4.0 * -log(rv[1]) ); |
| 364 |
> |
d = sqrt( -log(rv[1]) * np->alpha2 ); |
| 365 |
|
for (i = 0; i < 3; i++) |
| 366 |
|
sr.rdir[i] = np->prdir[i] + d*(cosp*u[i] + sinp*v[i]); |
| 367 |
|
if (DOT(sr.rdir, r->ron) < -FTINY) |
