1 |
#ifndef lint |
2 |
static const char RCSid[] = "$Id: m_bsdf.c,v 2.30 2015/09/02 18:59:01 greg Exp $"; |
3 |
#endif |
4 |
/* |
5 |
* Shading for materials with BSDFs taken from XML data files |
6 |
*/ |
7 |
|
8 |
#include "copyright.h" |
9 |
|
10 |
#include "ray.h" |
11 |
#include "ambient.h" |
12 |
#include "source.h" |
13 |
#include "func.h" |
14 |
#include "bsdf.h" |
15 |
#include "random.h" |
16 |
#include "pmapmat.h" |
17 |
|
18 |
/* |
19 |
* Arguments to this material include optional diffuse colors. |
20 |
* String arguments include the BSDF and function files. |
21 |
* A non-zero thickness causes the strange but useful behavior |
22 |
* of translating transmitted rays this distance beneath the surface |
23 |
* (opposite the surface normal) to bypass any intervening geometry. |
24 |
* Translation only affects scattered, non-source-directed samples. |
25 |
* A non-zero thickness has the further side-effect that an unscattered |
26 |
* (view) ray will pass right through our material if it has any |
27 |
* non-diffuse transmission, making the BSDF surface invisible. This |
28 |
* shows the proxied geometry instead. Thickness has the further |
29 |
* effect of turning off reflection on the hidden side so that rays |
30 |
* heading in the opposite direction pass unimpeded through the BSDF |
31 |
* surface. A paired surface may be placed on the opposide side of |
32 |
* the detail geometry, less than this thickness away, if a two-way |
33 |
* proxy is desired. Note that the sign of the thickness is important. |
34 |
* A positive thickness hides geometry behind the BSDF surface and uses |
35 |
* front reflectance and transmission properties. A negative thickness |
36 |
* hides geometry in front of the surface when rays hit from behind, |
37 |
* and applies only the transmission and backside reflectance properties. |
38 |
* Reflection is ignored on the hidden side, as those rays pass through. |
39 |
* The "up" vector for the BSDF is given by three variables, defined |
40 |
* (along with the thickness) by the named function file, or '.' if none. |
41 |
* Together with the surface normal, this defines the local coordinate |
42 |
* system for the BSDF. |
43 |
* We do not reorient the surface, so if the BSDF has no back-side |
44 |
* reflectance and none is given in the real arguments, a BSDF surface |
45 |
* with zero thickness will appear black when viewed from behind |
46 |
* unless backface visibility is off. |
47 |
* The diffuse arguments are added to components in the BSDF file, |
48 |
* not multiplied. However, patterns affect this material as a multiplier |
49 |
* on everything except non-diffuse reflection. |
50 |
* |
51 |
* Arguments for MAT_BSDF are: |
52 |
* 6+ thick BSDFfile ux uy uz funcfile transform |
53 |
* 0 |
54 |
* 0|3|6|9 rdf gdf bdf |
55 |
* rdb gdb bdb |
56 |
* rdt gdt bdt |
57 |
*/ |
58 |
|
59 |
/* |
60 |
* Note that our reverse ray-tracing process means that the positions |
61 |
* of incoming and outgoing vectors may be reversed in our calls |
62 |
* to the BSDF library. This is fine, since the bidirectional nature |
63 |
* of the BSDF (that's what the 'B' stands for) means it all works out. |
64 |
*/ |
65 |
|
66 |
typedef struct { |
67 |
OBJREC *mp; /* material pointer */ |
68 |
RAY *pr; /* intersected ray */ |
69 |
FVECT pnorm; /* perturbed surface normal */ |
70 |
FVECT vray; /* local outgoing (return) vector */ |
71 |
double sr_vpsa[2]; /* sqrt of BSDF projected solid angle extrema */ |
72 |
RREAL toloc[3][3]; /* world to local BSDF coords */ |
73 |
RREAL fromloc[3][3]; /* local BSDF coords to world */ |
74 |
double thick; /* surface thickness */ |
75 |
SDData *sd; /* loaded BSDF data */ |
76 |
COLOR rdiff; /* diffuse reflection */ |
77 |
COLOR tdiff; /* diffuse transmission */ |
78 |
} BSDFDAT; /* BSDF material data */ |
79 |
|
80 |
#define cvt_sdcolor(cv, svp) ccy2rgb(&(svp)->spec, (svp)->cieY, cv) |
81 |
|
82 |
/* Jitter ray sample according to projected solid angle and specjitter */ |
83 |
static void |
84 |
bsdf_jitter(FVECT vres, BSDFDAT *ndp, double sr_psa) |
85 |
{ |
86 |
VCOPY(vres, ndp->vray); |
87 |
if (specjitter < 1.) |
88 |
sr_psa *= specjitter; |
89 |
if (sr_psa <= FTINY) |
90 |
return; |
91 |
vres[0] += sr_psa*(.5 - frandom()); |
92 |
vres[1] += sr_psa*(.5 - frandom()); |
93 |
normalize(vres); |
94 |
} |
95 |
|
96 |
/* Evaluate BSDF for direct component, returning true if OK to proceed */ |
97 |
static int |
98 |
direct_bsdf_OK(COLOR cval, FVECT ldir, double omega, BSDFDAT *ndp) |
99 |
{ |
100 |
int nsamp, ok = 0; |
101 |
FVECT vsrc, vsmp, vjit; |
102 |
double tomega; |
103 |
double sf, tsr, sd[2]; |
104 |
COLOR csmp; |
105 |
SDValue sv; |
106 |
SDError ec; |
107 |
int i; |
108 |
/* transform source direction */ |
109 |
if (SDmapDir(vsrc, ndp->toloc, ldir) != SDEnone) |
110 |
return(0); |
111 |
/* assign number of samples */ |
112 |
ec = SDsizeBSDF(&tomega, ndp->vray, vsrc, SDqueryMin, ndp->sd); |
113 |
if (ec) |
114 |
goto baderror; |
115 |
/* check indirect over-counting */ |
116 |
if (ndp->thick != 0 && ndp->pr->crtype & (SPECULAR|AMBIENT) |
117 |
&& vsrc[2] > 0 ^ ndp->vray[2] > 0) { |
118 |
double dx = vsrc[0] + ndp->vray[0]; |
119 |
double dy = vsrc[1] + ndp->vray[1]; |
120 |
if (dx*dx + dy*dy <= omega+tomega) |
121 |
return(0); |
122 |
} |
123 |
sf = specjitter * ndp->pr->rweight; |
124 |
if (tomega <= .0) |
125 |
nsamp = 1; |
126 |
else if (25.*tomega <= omega) |
127 |
nsamp = 100.*sf + .5; |
128 |
else |
129 |
nsamp = 4.*sf*omega/tomega + .5; |
130 |
nsamp += !nsamp; |
131 |
setcolor(cval, .0, .0, .0); /* sample our source area */ |
132 |
sf = sqrt(omega); |
133 |
tsr = sqrt(tomega); |
134 |
for (i = nsamp; i--; ) { |
135 |
VCOPY(vsmp, vsrc); /* jitter query directions */ |
136 |
if (nsamp > 1) { |
137 |
multisamp(sd, 2, (i + frandom())/(double)nsamp); |
138 |
vsmp[0] += (sd[0] - .5)*sf; |
139 |
vsmp[1] += (sd[1] - .5)*sf; |
140 |
if (normalize(vsmp) == 0) { |
141 |
--nsamp; |
142 |
continue; |
143 |
} |
144 |
} |
145 |
bsdf_jitter(vjit, ndp, tsr); |
146 |
/* compute BSDF */ |
147 |
ec = SDevalBSDF(&sv, vjit, vsmp, ndp->sd); |
148 |
if (ec) |
149 |
goto baderror; |
150 |
if (sv.cieY <= FTINY) /* worth using? */ |
151 |
continue; |
152 |
cvt_sdcolor(csmp, &sv); |
153 |
addcolor(cval, csmp); /* average it in */ |
154 |
++ok; |
155 |
} |
156 |
sf = 1./(double)nsamp; |
157 |
scalecolor(cval, sf); |
158 |
return(ok); |
159 |
baderror: |
160 |
objerror(ndp->mp, USER, transSDError(ec)); |
161 |
return(0); /* gratis return */ |
162 |
} |
163 |
|
164 |
/* Compute source contribution for BSDF (reflected & transmitted) */ |
165 |
static void |
166 |
dir_bsdf( |
167 |
COLOR cval, /* returned coefficient */ |
168 |
void *nnp, /* material data */ |
169 |
FVECT ldir, /* light source direction */ |
170 |
double omega /* light source size */ |
171 |
) |
172 |
{ |
173 |
BSDFDAT *np = (BSDFDAT *)nnp; |
174 |
double ldot; |
175 |
double dtmp; |
176 |
COLOR ctmp; |
177 |
|
178 |
setcolor(cval, .0, .0, .0); |
179 |
|
180 |
ldot = DOT(np->pnorm, ldir); |
181 |
if ((-FTINY <= ldot) & (ldot <= FTINY)) |
182 |
return; |
183 |
|
184 |
if (ldot > 0 && bright(np->rdiff) > FTINY) { |
185 |
/* |
186 |
* Compute added diffuse reflected component. |
187 |
*/ |
188 |
copycolor(ctmp, np->rdiff); |
189 |
dtmp = ldot * omega * (1./PI); |
190 |
scalecolor(ctmp, dtmp); |
191 |
addcolor(cval, ctmp); |
192 |
} |
193 |
if (ldot < 0 && bright(np->tdiff) > FTINY) { |
194 |
/* |
195 |
* Compute added diffuse transmission. |
196 |
*/ |
197 |
copycolor(ctmp, np->tdiff); |
198 |
dtmp = -ldot * omega * (1.0/PI); |
199 |
scalecolor(ctmp, dtmp); |
200 |
addcolor(cval, ctmp); |
201 |
} |
202 |
if (ambRayInPmap(np->pr)) |
203 |
return; /* specular already in photon map */ |
204 |
/* |
205 |
* Compute scattering coefficient using BSDF. |
206 |
*/ |
207 |
if (!direct_bsdf_OK(ctmp, ldir, omega, np)) |
208 |
return; |
209 |
if (ldot < 0) { /* pattern for specular transmission */ |
210 |
multcolor(ctmp, np->pr->pcol); |
211 |
dtmp = -ldot * omega; |
212 |
} else |
213 |
dtmp = ldot * omega; |
214 |
scalecolor(ctmp, dtmp); |
215 |
addcolor(cval, ctmp); |
216 |
} |
217 |
|
218 |
/* Compute source contribution for BSDF (reflected only) */ |
219 |
static void |
220 |
dir_brdf( |
221 |
COLOR cval, /* returned coefficient */ |
222 |
void *nnp, /* material data */ |
223 |
FVECT ldir, /* light source direction */ |
224 |
double omega /* light source size */ |
225 |
) |
226 |
{ |
227 |
BSDFDAT *np = (BSDFDAT *)nnp; |
228 |
double ldot; |
229 |
double dtmp; |
230 |
COLOR ctmp, ctmp1, ctmp2; |
231 |
|
232 |
setcolor(cval, .0, .0, .0); |
233 |
|
234 |
ldot = DOT(np->pnorm, ldir); |
235 |
|
236 |
if (ldot <= FTINY) |
237 |
return; |
238 |
|
239 |
if (bright(np->rdiff) > FTINY) { |
240 |
/* |
241 |
* Compute added diffuse reflected component. |
242 |
*/ |
243 |
copycolor(ctmp, np->rdiff); |
244 |
dtmp = ldot * omega * (1./PI); |
245 |
scalecolor(ctmp, dtmp); |
246 |
addcolor(cval, ctmp); |
247 |
} |
248 |
if (ambRayInPmap(np->pr)) |
249 |
return; /* specular already in photon map */ |
250 |
/* |
251 |
* Compute reflection coefficient using BSDF. |
252 |
*/ |
253 |
if (!direct_bsdf_OK(ctmp, ldir, omega, np)) |
254 |
return; |
255 |
dtmp = ldot * omega; |
256 |
scalecolor(ctmp, dtmp); |
257 |
addcolor(cval, ctmp); |
258 |
} |
259 |
|
260 |
/* Compute source contribution for BSDF (transmitted only) */ |
261 |
static void |
262 |
dir_btdf( |
263 |
COLOR cval, /* returned coefficient */ |
264 |
void *nnp, /* material data */ |
265 |
FVECT ldir, /* light source direction */ |
266 |
double omega /* light source size */ |
267 |
) |
268 |
{ |
269 |
BSDFDAT *np = (BSDFDAT *)nnp; |
270 |
double ldot; |
271 |
double dtmp; |
272 |
COLOR ctmp; |
273 |
|
274 |
setcolor(cval, .0, .0, .0); |
275 |
|
276 |
ldot = DOT(np->pnorm, ldir); |
277 |
|
278 |
if (ldot >= -FTINY) |
279 |
return; |
280 |
|
281 |
if (bright(np->tdiff) > FTINY) { |
282 |
/* |
283 |
* Compute added diffuse transmission. |
284 |
*/ |
285 |
copycolor(ctmp, np->tdiff); |
286 |
dtmp = -ldot * omega * (1.0/PI); |
287 |
scalecolor(ctmp, dtmp); |
288 |
addcolor(cval, ctmp); |
289 |
} |
290 |
if (ambRayInPmap(np->pr)) |
291 |
return; /* specular already in photon map */ |
292 |
/* |
293 |
* Compute scattering coefficient using BSDF. |
294 |
*/ |
295 |
if (!direct_bsdf_OK(ctmp, ldir, omega, np)) |
296 |
return; |
297 |
/* full pattern on transmission */ |
298 |
multcolor(ctmp, np->pr->pcol); |
299 |
dtmp = -ldot * omega; |
300 |
scalecolor(ctmp, dtmp); |
301 |
addcolor(cval, ctmp); |
302 |
} |
303 |
|
304 |
/* Sample separate BSDF component */ |
305 |
static int |
306 |
sample_sdcomp(BSDFDAT *ndp, SDComponent *dcp, int usepat) |
307 |
{ |
308 |
int nstarget = 1; |
309 |
int nsent; |
310 |
SDError ec; |
311 |
SDValue bsv; |
312 |
double xrand; |
313 |
FVECT vsmp; |
314 |
RAY sr; |
315 |
/* multiple samples? */ |
316 |
if (specjitter > 1.5) { |
317 |
nstarget = specjitter*ndp->pr->rweight + .5; |
318 |
nstarget += !nstarget; |
319 |
} |
320 |
/* run through our samples */ |
321 |
for (nsent = 0; nsent < nstarget; nsent++) { |
322 |
if (nstarget == 1) { /* stratify random variable */ |
323 |
xrand = urand(ilhash(dimlist,ndims)+samplendx); |
324 |
if (specjitter < 1.) |
325 |
xrand = .5 + specjitter*(xrand-.5); |
326 |
} else { |
327 |
xrand = (nsent + frandom())/(double)nstarget; |
328 |
} |
329 |
SDerrorDetail[0] = '\0'; /* sample direction & coef. */ |
330 |
bsdf_jitter(vsmp, ndp, ndp->sr_vpsa[0]); |
331 |
ec = SDsampComponent(&bsv, vsmp, xrand, dcp); |
332 |
if (ec) |
333 |
objerror(ndp->mp, USER, transSDError(ec)); |
334 |
if (bsv.cieY <= FTINY) /* zero component? */ |
335 |
break; |
336 |
/* map vector to world */ |
337 |
if (SDmapDir(sr.rdir, ndp->fromloc, vsmp) != SDEnone) |
338 |
break; |
339 |
/* spawn a specular ray */ |
340 |
if (nstarget > 1) |
341 |
bsv.cieY /= (double)nstarget; |
342 |
cvt_sdcolor(sr.rcoef, &bsv); /* use sample color */ |
343 |
if (usepat) /* apply pattern? */ |
344 |
multcolor(sr.rcoef, ndp->pr->pcol); |
345 |
if (rayorigin(&sr, SPECULAR, ndp->pr, sr.rcoef) < 0) { |
346 |
if (maxdepth > 0) |
347 |
break; |
348 |
continue; /* Russian roulette victim */ |
349 |
} |
350 |
/* need to offset origin? */ |
351 |
if (ndp->thick != 0 && ndp->pr->rod > 0 ^ vsmp[2] > 0) |
352 |
VSUM(sr.rorg, sr.rorg, ndp->pr->ron, -ndp->thick); |
353 |
rayvalue(&sr); /* send & evaluate sample */ |
354 |
multcolor(sr.rcol, sr.rcoef); |
355 |
addcolor(ndp->pr->rcol, sr.rcol); |
356 |
} |
357 |
return(nsent); |
358 |
} |
359 |
|
360 |
/* Sample non-diffuse components of BSDF */ |
361 |
static int |
362 |
sample_sdf(BSDFDAT *ndp, int sflags) |
363 |
{ |
364 |
int n, ntotal = 0; |
365 |
SDSpectralDF *dfp; |
366 |
COLORV *unsc; |
367 |
|
368 |
if (sflags == SDsampSpT) { |
369 |
unsc = ndp->tdiff; |
370 |
if (ndp->pr->rod > 0) |
371 |
dfp = (ndp->sd->tf != NULL) ? ndp->sd->tf : ndp->sd->tb; |
372 |
else |
373 |
dfp = (ndp->sd->tb != NULL) ? ndp->sd->tb : ndp->sd->tf; |
374 |
} else /* sflags == SDsampSpR */ { |
375 |
unsc = ndp->rdiff; |
376 |
if (ndp->pr->rod > 0) |
377 |
dfp = ndp->sd->rf; |
378 |
else |
379 |
dfp = ndp->sd->rb; |
380 |
} |
381 |
if (dfp == NULL) /* no specular component? */ |
382 |
return(0); |
383 |
/* below sampling threshold? */ |
384 |
if (dfp->maxHemi <= specthresh+FTINY) { |
385 |
if (dfp->maxHemi > FTINY) { /* XXX no color from BSDF */ |
386 |
FVECT vjit; |
387 |
double d; |
388 |
COLOR ctmp; |
389 |
bsdf_jitter(vjit, ndp, ndp->sr_vpsa[1]); |
390 |
d = SDdirectHemi(vjit, sflags, ndp->sd); |
391 |
if (sflags == SDsampSpT) { |
392 |
copycolor(ctmp, ndp->pr->pcol); |
393 |
scalecolor(ctmp, d); |
394 |
} else /* no pattern on reflection */ |
395 |
setcolor(ctmp, d, d, d); |
396 |
addcolor(unsc, ctmp); |
397 |
} |
398 |
return(0); |
399 |
} |
400 |
/* else need to sample */ |
401 |
dimlist[ndims++] = (int)(size_t)ndp->mp; |
402 |
ndims++; |
403 |
for (n = dfp->ncomp; n--; ) { /* loop over components */ |
404 |
dimlist[ndims-1] = n + 9438; |
405 |
ntotal += sample_sdcomp(ndp, &dfp->comp[n], sflags==SDsampSpT); |
406 |
} |
407 |
ndims -= 2; |
408 |
return(ntotal); |
409 |
} |
410 |
|
411 |
/* Color a ray that hit a BSDF material */ |
412 |
int |
413 |
m_bsdf(OBJREC *m, RAY *r) |
414 |
{ |
415 |
int hitfront; |
416 |
COLOR ctmp; |
417 |
SDError ec; |
418 |
FVECT upvec, vtmp; |
419 |
MFUNC *mf; |
420 |
BSDFDAT nd; |
421 |
/* check arguments */ |
422 |
if ((m->oargs.nsargs < 6) | (m->oargs.nfargs > 9) | |
423 |
(m->oargs.nfargs % 3)) |
424 |
objerror(m, USER, "bad # arguments"); |
425 |
/* record surface struck */ |
426 |
hitfront = (r->rod > 0); |
427 |
/* load cal file */ |
428 |
mf = getfunc(m, 5, 0x1d, 1); |
429 |
setfunc(m, r); |
430 |
/* get thickness */ |
431 |
nd.thick = evalue(mf->ep[0]); |
432 |
if ((-FTINY <= nd.thick) & (nd.thick <= FTINY)) |
433 |
nd.thick = .0; |
434 |
/* check shadow */ |
435 |
if (r->crtype & SHADOW) { |
436 |
if (nd.thick != 0) |
437 |
raytrans(r); /* pass-through */ |
438 |
return(1); /* or shadow */ |
439 |
} |
440 |
/* check backface visibility */ |
441 |
if (!hitfront & !backvis) { |
442 |
raytrans(r); |
443 |
return(1); |
444 |
} |
445 |
/* check other rays to pass */ |
446 |
if (nd.thick != 0 && (!(r->crtype & (SPECULAR|AMBIENT)) || |
447 |
(nd.thick > 0) ^ hitfront)) { |
448 |
raytrans(r); /* hide our proxy */ |
449 |
return(1); |
450 |
} |
451 |
nd.mp = m; |
452 |
nd.pr = r; |
453 |
/* get BSDF data */ |
454 |
nd.sd = loadBSDF(m->oargs.sarg[1]); |
455 |
/* diffuse reflectance */ |
456 |
if (hitfront) { |
457 |
cvt_sdcolor(nd.rdiff, &nd.sd->rLambFront); |
458 |
if (m->oargs.nfargs >= 3) { |
459 |
setcolor(ctmp, m->oargs.farg[0], |
460 |
m->oargs.farg[1], |
461 |
m->oargs.farg[2]); |
462 |
addcolor(nd.rdiff, ctmp); |
463 |
} |
464 |
} else { |
465 |
cvt_sdcolor(nd.rdiff, &nd.sd->rLambBack); |
466 |
if (m->oargs.nfargs >= 6) { |
467 |
setcolor(ctmp, m->oargs.farg[3], |
468 |
m->oargs.farg[4], |
469 |
m->oargs.farg[5]); |
470 |
addcolor(nd.rdiff, ctmp); |
471 |
} |
472 |
} |
473 |
/* diffuse transmittance */ |
474 |
cvt_sdcolor(nd.tdiff, &nd.sd->tLamb); |
475 |
if (m->oargs.nfargs >= 9) { |
476 |
setcolor(ctmp, m->oargs.farg[6], |
477 |
m->oargs.farg[7], |
478 |
m->oargs.farg[8]); |
479 |
addcolor(nd.tdiff, ctmp); |
480 |
} |
481 |
/* get modifiers */ |
482 |
raytexture(r, m->omod); |
483 |
/* modify diffuse values */ |
484 |
multcolor(nd.rdiff, r->pcol); |
485 |
multcolor(nd.tdiff, r->pcol); |
486 |
/* get up vector */ |
487 |
upvec[0] = evalue(mf->ep[1]); |
488 |
upvec[1] = evalue(mf->ep[2]); |
489 |
upvec[2] = evalue(mf->ep[3]); |
490 |
/* return to world coords */ |
491 |
if (mf->fxp != &unitxf) { |
492 |
multv3(upvec, upvec, mf->fxp->xfm); |
493 |
nd.thick *= mf->fxp->sca; |
494 |
} |
495 |
if (r->rox != NULL) { |
496 |
multv3(upvec, upvec, r->rox->f.xfm); |
497 |
nd.thick *= r->rox->f.sca; |
498 |
} |
499 |
raynormal(nd.pnorm, r); |
500 |
/* compute local BSDF xform */ |
501 |
ec = SDcompXform(nd.toloc, nd.pnorm, upvec); |
502 |
if (!ec) { |
503 |
nd.vray[0] = -r->rdir[0]; |
504 |
nd.vray[1] = -r->rdir[1]; |
505 |
nd.vray[2] = -r->rdir[2]; |
506 |
ec = SDmapDir(nd.vray, nd.toloc, nd.vray); |
507 |
} |
508 |
if (!ec) |
509 |
ec = SDinvXform(nd.fromloc, nd.toloc); |
510 |
if (ec) { |
511 |
objerror(m, WARNING, "Illegal orientation vector"); |
512 |
return(1); |
513 |
} |
514 |
/* determine BSDF resolution */ |
515 |
ec = SDsizeBSDF(nd.sr_vpsa, nd.vray, NULL, SDqueryMin+SDqueryMax, nd.sd); |
516 |
if (ec) |
517 |
objerror(m, USER, transSDError(ec)); |
518 |
|
519 |
nd.sr_vpsa[0] = sqrt(nd.sr_vpsa[0]); |
520 |
nd.sr_vpsa[1] = sqrt(nd.sr_vpsa[1]); |
521 |
if (!hitfront) { /* perturb normal towards hit */ |
522 |
nd.pnorm[0] = -nd.pnorm[0]; |
523 |
nd.pnorm[1] = -nd.pnorm[1]; |
524 |
nd.pnorm[2] = -nd.pnorm[2]; |
525 |
} |
526 |
/* sample reflection */ |
527 |
sample_sdf(&nd, SDsampSpR); |
528 |
/* sample transmission */ |
529 |
sample_sdf(&nd, SDsampSpT); |
530 |
/* compute indirect diffuse */ |
531 |
if (bright(nd.rdiff) > FTINY) { /* ambient from reflection */ |
532 |
if (!hitfront) |
533 |
flipsurface(r); |
534 |
copycolor(ctmp, nd.rdiff); |
535 |
multambient(ctmp, r, nd.pnorm); |
536 |
addcolor(r->rcol, ctmp); |
537 |
if (!hitfront) |
538 |
flipsurface(r); |
539 |
} |
540 |
if (bright(nd.tdiff) > FTINY) { /* ambient from other side */ |
541 |
FVECT bnorm; |
542 |
if (hitfront) |
543 |
flipsurface(r); |
544 |
bnorm[0] = -nd.pnorm[0]; |
545 |
bnorm[1] = -nd.pnorm[1]; |
546 |
bnorm[2] = -nd.pnorm[2]; |
547 |
copycolor(ctmp, nd.tdiff); |
548 |
if (nd.thick != 0) { /* proxy with offset? */ |
549 |
VCOPY(vtmp, r->rop); |
550 |
VSUM(r->rop, vtmp, r->ron, nd.thick); |
551 |
multambient(ctmp, r, bnorm); |
552 |
VCOPY(r->rop, vtmp); |
553 |
} else |
554 |
multambient(ctmp, r, bnorm); |
555 |
addcolor(r->rcol, ctmp); |
556 |
if (hitfront) |
557 |
flipsurface(r); |
558 |
} |
559 |
/* add direct component */ |
560 |
if ((bright(nd.tdiff) <= FTINY) & (nd.sd->tf == NULL) & |
561 |
(nd.sd->tb == NULL)) { |
562 |
direct(r, dir_brdf, &nd); /* reflection only */ |
563 |
} else if (nd.thick == 0) { |
564 |
direct(r, dir_bsdf, &nd); /* thin surface scattering */ |
565 |
} else { |
566 |
direct(r, dir_brdf, &nd); /* reflection first */ |
567 |
VCOPY(vtmp, r->rop); /* offset for transmitted */ |
568 |
VSUM(r->rop, vtmp, r->ron, -nd.thick); |
569 |
direct(r, dir_btdf, &nd); /* separate transmission */ |
570 |
VCOPY(r->rop, vtmp); |
571 |
} |
572 |
/* clean up */ |
573 |
SDfreeCache(nd.sd); |
574 |
return(1); |
575 |
} |