25 |
|
#endif |
26 |
|
/* estimate of Fresnel function */ |
27 |
|
#define FRESNE(ci) (exp(-5.85*(ci)) - 0.00287989916) |
28 |
+ |
#define FRESTHRESH 0.017999 /* minimum specularity for approx. */ |
29 |
|
|
30 |
|
|
31 |
|
/* |
80 |
|
register NORMDAT *np = nnp; |
81 |
|
double ldot; |
82 |
|
double lrdiff, ltdiff; |
83 |
< |
double dtmp, d2; |
83 |
> |
double dtmp, d2, d3, d4; |
84 |
|
FVECT vtmp; |
85 |
|
COLOR ctmp; |
86 |
|
|
94 |
|
/* Fresnel estimate */ |
95 |
|
lrdiff = np->rdiff; |
96 |
|
ltdiff = np->tdiff; |
97 |
< |
if (np->specfl & SP_PURE && np->rspec > FTINY && |
97 |
> |
if (np->specfl & SP_PURE && np->rspec >= FRESTHRESH && |
98 |
|
(lrdiff > FTINY) | (ltdiff > FTINY)) { |
99 |
|
dtmp = 1. - FRESNE(fabs(ldot)); |
100 |
|
lrdiff *= dtmp; |
115 |
|
if (ldot > FTINY && (np->specfl&(SP_REFL|SP_PURE)) == SP_REFL) { |
116 |
|
/* |
117 |
|
* Compute specular reflection coefficient using |
118 |
< |
* gaussian distribution model. |
118 |
> |
* Gaussian distribution model. |
119 |
|
*/ |
120 |
|
/* roughness */ |
121 |
|
dtmp = np->alpha2; |
128 |
|
vtmp[2] = ldir[2] - np->rp->rdir[2]; |
129 |
|
d2 = DOT(vtmp, np->pnorm); |
130 |
|
d2 *= d2; |
131 |
< |
d2 = (DOT(vtmp,vtmp) - d2) / d2; |
132 |
< |
/* gaussian */ |
133 |
< |
dtmp = exp(-d2/dtmp)/(4.*PI * np->pdot * dtmp); |
131 |
> |
d3 = DOT(vtmp,vtmp); |
132 |
> |
d4 = (d3 - d2) / d2; |
133 |
> |
/* new W-G-M-D model */ |
134 |
> |
dtmp = exp(-d4/dtmp) * d3 / (PI * d2*d2 * dtmp); |
135 |
|
/* worth using? */ |
136 |
|
if (dtmp > FTINY) { |
137 |
|
copycolor(ctmp, np->scolor); |
138 |
< |
dtmp *= omega; |
138 |
> |
dtmp *= ldot * omega; |
139 |
|
scalecolor(ctmp, dtmp); |
140 |
|
addcolor(cval, ctmp); |
141 |
|
} |
156 |
|
*/ |
157 |
|
/* roughness + source */ |
158 |
|
dtmp = np->alpha2 + omega*(1.0/PI); |
159 |
< |
/* gaussian */ |
160 |
< |
dtmp = exp((2.*DOT(np->prdir,ldir)-2.)/dtmp) / |
159 |
< |
(PI*np->pdot*dtmp); |
159 |
> |
/* Gaussian */ |
160 |
> |
dtmp = exp((2.*DOT(np->prdir,ldir)-2.)/dtmp)/(PI*dtmp); |
161 |
|
/* worth using? */ |
162 |
|
if (dtmp > FTINY) { |
163 |
|
copycolor(ctmp, np->mcolor); |
164 |
< |
dtmp *= np->tspec * omega; |
164 |
> |
dtmp *= np->tspec * omega * sqrt(-ldot/np->pdot); |
165 |
|
scalecolor(ctmp, dtmp); |
166 |
|
addcolor(cval, ctmp); |
167 |
|
} |
226 |
|
mirdist = transdist = r->rot; |
227 |
|
nd.rspec = m->oargs.farg[3]; |
228 |
|
/* compute Fresnel approx. */ |
229 |
< |
if (nd.specfl & SP_PURE && nd.rspec > FTINY) { |
229 |
> |
if (nd.specfl & SP_PURE && nd.rspec >= FRESTHRESH) { |
230 |
|
fest = FRESNE(r->rod); |
231 |
|
nd.rspec += fest*(1. - nd.rspec); |
232 |
|
} else |
294 |
|
if (!(nd.specfl & SP_PURE) && specthresh >= nd.rspec-FTINY) |
295 |
|
nd.specfl |= SP_RBLT; |
296 |
|
/* compute reflected ray */ |
297 |
< |
for (i = 0; i < 3; i++) |
297 |
< |
nd.vrefl[i] = r->rdir[i] + 2.*nd.pdot*nd.pnorm[i]; |
297 |
> |
VSUM(nd.vrefl, r->rdir, nd.pnorm, 2.*nd.pdot); |
298 |
|
/* penetration? */ |
299 |
|
if (hastexture && DOT(nd.vrefl, r->ron) <= FTINY) |
300 |
< |
for (i = 0; i < 3; i++) /* safety measure */ |
301 |
< |
nd.vrefl[i] = r->rdir[i] + 2.*r->rod*r->ron[i]; |
300 |
> |
VSUM(nd.vrefl, r->rdir, r->ron, 2.*r->rod); |
301 |
> |
checknorm(nd.vrefl); |
302 |
|
} |
303 |
|
/* reflected ray */ |
304 |
|
if ((nd.specfl&(SP_REFL|SP_PURE|SP_RBLT)) == (SP_REFL|SP_PURE)) { |
364 |
|
|
365 |
|
|
366 |
|
static void |
367 |
< |
gaussamp( /* sample gaussian specular */ |
367 |
> |
gaussamp( /* sample Gaussian specular */ |
368 |
|
RAY *r, |
369 |
|
register NORMDAT *np |
370 |
|
) |
373 |
|
FVECT u, v, h; |
374 |
|
double rv[2]; |
375 |
|
double d, sinp, cosp; |
376 |
< |
int niter; |
376 |
> |
COLOR scol; |
377 |
> |
int maxiter, ntrials, nstarget, nstaken; |
378 |
|
register int i; |
379 |
|
/* quick test */ |
380 |
|
if ((np->specfl & (SP_REFL|SP_RBLT)) != SP_REFL && |
392 |
|
/* compute reflection */ |
393 |
|
if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL && |
394 |
|
rayorigin(&sr, SPECULAR, r, np->scolor) == 0) { |
395 |
+ |
nstarget = 1; |
396 |
+ |
if (specjitter > 1.5) { /* multiple samples? */ |
397 |
+ |
nstarget = specjitter*r->rweight + .5; |
398 |
+ |
if (sr.rweight <= minweight*nstarget) |
399 |
+ |
nstarget = sr.rweight/minweight; |
400 |
+ |
if (nstarget > 1) { |
401 |
+ |
d = 1./nstarget; |
402 |
+ |
scalecolor(sr.rcoef, d); |
403 |
+ |
sr.rweight *= d; |
404 |
+ |
} else |
405 |
+ |
nstarget = 1; |
406 |
+ |
} |
407 |
+ |
setcolor(scol, 0., 0., 0.); |
408 |
|
dimlist[ndims++] = (int)np->mp; |
409 |
< |
for (niter = 0; niter < MAXITER; niter++) { |
410 |
< |
if (niter) |
409 |
> |
maxiter = MAXITER*nstarget; |
410 |
> |
for (nstaken = ntrials = 0; nstaken < nstarget && |
411 |
> |
ntrials < maxiter; ntrials++) { |
412 |
> |
if (ntrials) |
413 |
|
d = frandom(); |
414 |
|
else |
415 |
|
d = urand(ilhash(dimlist,ndims)+samplendx); |
417 |
|
d = 2.0*PI * rv[0]; |
418 |
|
cosp = tcos(d); |
419 |
|
sinp = tsin(d); |
420 |
< |
rv[1] = 1.0 - specjitter*rv[1]; |
420 |
> |
if ((0. <= specjitter) & (specjitter < 1.)) |
421 |
> |
rv[1] = 1.0 - specjitter*rv[1]; |
422 |
|
if (rv[1] <= FTINY) |
423 |
|
d = 1.0; |
424 |
|
else |
426 |
|
for (i = 0; i < 3; i++) |
427 |
|
h[i] = np->pnorm[i] + d*(cosp*u[i] + sinp*v[i]); |
428 |
|
d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d); |
429 |
< |
for (i = 0; i < 3; i++) |
430 |
< |
sr.rdir[i] = r->rdir[i] + d*h[i]; |
431 |
< |
if (DOT(sr.rdir, r->ron) > FTINY) { |
429 |
> |
VSUM(sr.rdir, r->rdir, h, d); |
430 |
> |
/* sample rejection test */ |
431 |
> |
if ((d = DOT(sr.rdir, r->ron)) <= FTINY) |
432 |
> |
continue; |
433 |
> |
checknorm(sr.rdir); |
434 |
> |
if (nstarget > 1) { /* W-G-M-D adjustment */ |
435 |
> |
if (nstaken) rayclear(&sr); |
436 |
|
rayvalue(&sr); |
437 |
+ |
d = 2./(1. + r->rod/d); |
438 |
+ |
scalecolor(sr.rcol, d); |
439 |
+ |
addcolor(scol, sr.rcol); |
440 |
+ |
} else { |
441 |
+ |
rayvalue(&sr); |
442 |
|
multcolor(sr.rcol, sr.rcoef); |
443 |
|
addcolor(r->rcol, sr.rcol); |
418 |
– |
break; |
444 |
|
} |
445 |
+ |
++nstaken; |
446 |
|
} |
447 |
+ |
if (nstarget > 1) { /* final W-G-M-D weighting */ |
448 |
+ |
multcolor(scol, sr.rcoef); |
449 |
+ |
d = (double)nstarget/ntrials; |
450 |
+ |
scalecolor(scol, d); |
451 |
+ |
addcolor(r->rcol, scol); |
452 |
+ |
} |
453 |
|
ndims--; |
454 |
|
} |
455 |
|
/* compute transmission */ |
457 |
|
scalecolor(sr.rcoef, np->tspec); |
458 |
|
if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN && |
459 |
|
rayorigin(&sr, SPECULAR, r, sr.rcoef) == 0) { |
460 |
+ |
nstarget = 1; |
461 |
+ |
if (specjitter > 1.5) { /* multiple samples? */ |
462 |
+ |
nstarget = specjitter*r->rweight + .5; |
463 |
+ |
if (sr.rweight <= minweight*nstarget) |
464 |
+ |
nstarget = sr.rweight/minweight; |
465 |
+ |
if (nstarget > 1) { |
466 |
+ |
d = 1./nstarget; |
467 |
+ |
scalecolor(sr.rcoef, d); |
468 |
+ |
sr.rweight *= d; |
469 |
+ |
} else |
470 |
+ |
nstarget = 1; |
471 |
+ |
} |
472 |
|
dimlist[ndims++] = (int)np->mp; |
473 |
< |
for (niter = 0; niter < MAXITER; niter++) { |
474 |
< |
if (niter) |
473 |
> |
maxiter = MAXITER*nstarget; |
474 |
> |
for (nstaken = ntrials = 0; nstaken < nstarget && |
475 |
> |
ntrials < maxiter; ntrials++) { |
476 |
> |
if (ntrials) |
477 |
|
d = frandom(); |
478 |
|
else |
479 |
< |
d = urand(ilhash(dimlist,ndims)+1823+samplendx); |
479 |
> |
d = urand(ilhash(dimlist,ndims)+samplendx); |
480 |
|
multisamp(rv, 2, d); |
481 |
|
d = 2.0*PI * rv[0]; |
482 |
|
cosp = tcos(d); |
483 |
|
sinp = tsin(d); |
484 |
< |
rv[1] = 1.0 - specjitter*rv[1]; |
484 |
> |
if ((0. <= specjitter) & (specjitter < 1.)) |
485 |
> |
rv[1] = 1.0 - specjitter*rv[1]; |
486 |
|
if (rv[1] <= FTINY) |
487 |
|
d = 1.0; |
488 |
|
else |
489 |
|
d = sqrt( np->alpha2 * -log(rv[1]) ); |
490 |
|
for (i = 0; i < 3; i++) |
491 |
|
sr.rdir[i] = np->prdir[i] + d*(cosp*u[i] + sinp*v[i]); |
492 |
< |
if (DOT(sr.rdir, r->ron) < -FTINY) { |
493 |
< |
normalize(sr.rdir); /* OK, normalize */ |
494 |
< |
rayvalue(&sr); |
495 |
< |
multcolor(sr.rcol, sr.rcoef); |
496 |
< |
addcolor(r->rcol, sr.rcol); |
497 |
< |
break; |
498 |
< |
} |
492 |
> |
/* sample rejection test */ |
493 |
> |
if (DOT(sr.rdir, r->ron) >= -FTINY) |
494 |
> |
continue; |
495 |
> |
normalize(sr.rdir); /* OK, normalize */ |
496 |
> |
if (nstaken) /* multi-sampling */ |
497 |
> |
rayclear(&sr); |
498 |
> |
rayvalue(&sr); |
499 |
> |
multcolor(sr.rcol, sr.rcoef); |
500 |
> |
addcolor(r->rcol, sr.rcol); |
501 |
> |
++nstaken; |
502 |
|
} |
503 |
|
ndims--; |
504 |
|
} |