1 |
#ifndef lint |
2 |
static const char RCSid[] = "$Id: m_bsdf.c,v 2.10 2011/04/24 19:39:21 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 |
|
17 |
/* |
18 |
* Arguments to this material include optional diffuse colors. |
19 |
* String arguments include the BSDF and function files. |
20 |
* A non-zero thickness causes the strange but useful behavior |
21 |
* of translating transmitted rays this distance beneath the surface |
22 |
* (opposite the surface normal) to bypass any intervening geometry. |
23 |
* Translation only affects scattered, non-source-directed samples. |
24 |
* A non-zero thickness has the further side-effect that an unscattered |
25 |
* (view) ray will pass right through our material if it has any |
26 |
* non-diffuse transmission, making the BSDF surface invisible. This |
27 |
* shows the proxied geometry instead. Thickness has the further |
28 |
* effect of turning off reflection on the hidden side so that rays |
29 |
* heading in the opposite direction pass unimpeded through the BSDF |
30 |
* surface. A paired surface may be placed on the opposide side of |
31 |
* the detail geometry, less than this thickness away, if a two-way |
32 |
* proxy is desired. Note that the sign of the thickness is important. |
33 |
* A positive thickness hides geometry behind the BSDF surface and uses |
34 |
* front reflectance and transmission properties. A negative thickness |
35 |
* hides geometry in front of the surface when rays hit from behind, |
36 |
* and applies only the transmission and backside reflectance properties. |
37 |
* Reflection is ignored on the hidden side, as those rays pass through. |
38 |
* The "up" vector for the BSDF is given by three variables, defined |
39 |
* (along with the thickness) by the named function file, or '.' if none. |
40 |
* Together with the surface normal, this defines the local coordinate |
41 |
* system for the BSDF. |
42 |
* We do not reorient the surface, so if the BSDF has no back-side |
43 |
* reflectance and none is given in the real arguments, a BSDF surface |
44 |
* with zero thickness will appear black when viewed from behind |
45 |
* unless backface visibility is off. |
46 |
* The diffuse arguments are added to components in the BSDF file, |
47 |
* not multiplied. However, patterns affect this material as a multiplier |
48 |
* on everything except non-diffuse reflection. |
49 |
* |
50 |
* Arguments for MAT_BSDF are: |
51 |
* 6+ thick BSDFfile ux uy uz funcfile transform |
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* 0 |
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* 0|3|6|9 rdf gdf bdf |
54 |
* rdb gdb bdb |
55 |
* rdt gdt bdt |
56 |
*/ |
57 |
|
58 |
/* |
59 |
* Note that our reverse ray-tracing process means that the positions |
60 |
* of incoming and outgoing vectors may be reversed in our calls |
61 |
* to the BSDF library. This is fine, since the bidirectional nature |
62 |
* of the BSDF (that's what the 'B' stands for) means it all works out. |
63 |
*/ |
64 |
|
65 |
typedef struct { |
66 |
OBJREC *mp; /* material pointer */ |
67 |
RAY *pr; /* intersected ray */ |
68 |
FVECT pnorm; /* perturbed surface normal */ |
69 |
FVECT vray; /* local outgoing (return) vector */ |
70 |
double sr_vpsa[2]; /* sqrt of BSDF projected solid angle extrema */ |
71 |
double thru_psa; /* through direction projected solid angle */ |
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RREAL toloc[3][3]; /* world to local BSDF coords */ |
73 |
RREAL fromloc[3][3]; /* local BSDF coords to world */ |
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double thick; /* surface thickness */ |
75 |
SDData *sd; /* loaded BSDF data */ |
76 |
COLOR runsamp; /* BSDF hemispherical reflection */ |
77 |
COLOR rdiff; /* added diffuse reflection */ |
78 |
COLOR tunsamp; /* BSDF hemispherical transmission */ |
79 |
COLOR tdiff; /* added diffuse transmission */ |
80 |
} BSDFDAT; /* BSDF material data */ |
81 |
|
82 |
#define cvt_sdcolor(cv, svp) ccy2rgb(&(svp)->spec, (svp)->cieY, cv) |
83 |
|
84 |
/* Jitter ray sample according to projected solid angle and specjitter */ |
85 |
static void |
86 |
bsdf_jitter(FVECT vres, BSDFDAT *ndp, int domax) |
87 |
{ |
88 |
double sr_psa = ndp->sr_vpsa[domax]; |
89 |
|
90 |
VCOPY(vres, ndp->vray); |
91 |
if (specjitter < 1.) |
92 |
sr_psa *= specjitter; |
93 |
if (sr_psa <= FTINY) |
94 |
return; |
95 |
vres[0] += sr_psa*(.5 - frandom()); |
96 |
vres[1] += sr_psa*(.5 - frandom()); |
97 |
normalize(vres); |
98 |
} |
99 |
|
100 |
/* Evaluate BSDF for direct component, returning true if OK to proceed */ |
101 |
static int |
102 |
direct_bsdf_OK(COLOR cval, FVECT ldir, BSDFDAT *ndp) |
103 |
{ |
104 |
FVECT vsrc, vjit; |
105 |
SDValue sv; |
106 |
SDError ec; |
107 |
/* transform source direction */ |
108 |
if (SDmapDir(vsrc, ndp->toloc, ldir) != SDEnone) |
109 |
return(0); |
110 |
/* jitter query direction */ |
111 |
bsdf_jitter(vjit, ndp, 0); |
112 |
/* avoid indirect over-counting */ |
113 |
if (ndp->thick != 0 && ndp->pr->crtype & (SPECULAR|AMBIENT) && |
114 |
vsrc[2] > 0 ^ vjit[2] > 0) { |
115 |
double dx = vsrc[0] + vjit[0]; |
116 |
double dy = vsrc[1] + vjit[1]; |
117 |
if (dx*dx + dy*dy <= ndp->thru_psa) |
118 |
return(0); |
119 |
} |
120 |
ec = SDevalBSDF(&sv, vjit, vsrc, ndp->sd); |
121 |
if (ec) |
122 |
objerror(ndp->mp, USER, transSDError(ec)); |
123 |
|
124 |
if (sv.cieY <= FTINY) /* not worth using? */ |
125 |
return(0); |
126 |
/* else we're good to go */ |
127 |
cvt_sdcolor(cval, &sv); |
128 |
return(1); |
129 |
} |
130 |
|
131 |
/* Compute source contribution for BSDF (reflected & transmitted) */ |
132 |
static void |
133 |
dir_bsdf( |
134 |
COLOR cval, /* returned coefficient */ |
135 |
void *nnp, /* material data */ |
136 |
FVECT ldir, /* light source direction */ |
137 |
double omega /* light source size */ |
138 |
) |
139 |
{ |
140 |
BSDFDAT *np = (BSDFDAT *)nnp; |
141 |
double ldot; |
142 |
double dtmp; |
143 |
COLOR ctmp; |
144 |
|
145 |
setcolor(cval, .0, .0, .0); |
146 |
|
147 |
ldot = DOT(np->pnorm, ldir); |
148 |
if ((-FTINY <= ldot) & (ldot <= FTINY)) |
149 |
return; |
150 |
|
151 |
if (ldot > 0 && bright(np->rdiff) > FTINY) { |
152 |
/* |
153 |
* Compute added diffuse reflected component. |
154 |
*/ |
155 |
copycolor(ctmp, np->rdiff); |
156 |
dtmp = ldot * omega * (1./PI); |
157 |
scalecolor(ctmp, dtmp); |
158 |
addcolor(cval, ctmp); |
159 |
} |
160 |
if (ldot < 0 && bright(np->tdiff) > FTINY) { |
161 |
/* |
162 |
* Compute added diffuse transmission. |
163 |
*/ |
164 |
copycolor(ctmp, np->tdiff); |
165 |
dtmp = -ldot * omega * (1.0/PI); |
166 |
scalecolor(ctmp, dtmp); |
167 |
addcolor(cval, ctmp); |
168 |
} |
169 |
/* |
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* Compute scattering coefficient using BSDF. |
171 |
*/ |
172 |
if (!direct_bsdf_OK(ctmp, ldir, np)) |
173 |
return; |
174 |
if (ldot > 0) { /* pattern only diffuse reflection */ |
175 |
COLOR ctmp1, ctmp2; |
176 |
dtmp = (np->pr->rod > 0) ? np->sd->rLambFront.cieY |
177 |
: np->sd->rLambBack.cieY; |
178 |
/* diffuse fraction */ |
179 |
dtmp /= PI * bright(ctmp); |
180 |
copycolor(ctmp2, np->pr->pcol); |
181 |
scalecolor(ctmp2, dtmp); |
182 |
setcolor(ctmp1, 1.-dtmp, 1.-dtmp, 1.-dtmp); |
183 |
addcolor(ctmp1, ctmp2); |
184 |
multcolor(ctmp, ctmp1); /* apply derated pattern */ |
185 |
dtmp = ldot * omega; |
186 |
} else { /* full pattern on transmission */ |
187 |
multcolor(ctmp, np->pr->pcol); |
188 |
dtmp = -ldot * omega; |
189 |
} |
190 |
scalecolor(ctmp, dtmp); |
191 |
addcolor(cval, ctmp); |
192 |
} |
193 |
|
194 |
/* Compute source contribution for BSDF (reflected only) */ |
195 |
static void |
196 |
dir_brdf( |
197 |
COLOR cval, /* returned coefficient */ |
198 |
void *nnp, /* material data */ |
199 |
FVECT ldir, /* light source direction */ |
200 |
double omega /* light source size */ |
201 |
) |
202 |
{ |
203 |
BSDFDAT *np = (BSDFDAT *)nnp; |
204 |
double ldot; |
205 |
double dtmp; |
206 |
COLOR ctmp, ctmp1, ctmp2; |
207 |
|
208 |
setcolor(cval, .0, .0, .0); |
209 |
|
210 |
ldot = DOT(np->pnorm, ldir); |
211 |
|
212 |
if (ldot <= FTINY) |
213 |
return; |
214 |
|
215 |
if (bright(np->rdiff) > FTINY) { |
216 |
/* |
217 |
* Compute added diffuse reflected component. |
218 |
*/ |
219 |
copycolor(ctmp, np->rdiff); |
220 |
dtmp = ldot * omega * (1./PI); |
221 |
scalecolor(ctmp, dtmp); |
222 |
addcolor(cval, ctmp); |
223 |
} |
224 |
/* |
225 |
* Compute reflection coefficient using BSDF. |
226 |
*/ |
227 |
if (!direct_bsdf_OK(ctmp, ldir, np)) |
228 |
return; |
229 |
/* pattern only diffuse reflection */ |
230 |
dtmp = (np->pr->rod > 0) ? np->sd->rLambFront.cieY |
231 |
: np->sd->rLambBack.cieY; |
232 |
dtmp /= PI * bright(ctmp); /* diffuse fraction */ |
233 |
copycolor(ctmp2, np->pr->pcol); |
234 |
scalecolor(ctmp2, dtmp); |
235 |
setcolor(ctmp1, 1.-dtmp, 1.-dtmp, 1.-dtmp); |
236 |
addcolor(ctmp1, ctmp2); |
237 |
multcolor(ctmp, ctmp1); /* apply derated pattern */ |
238 |
dtmp = ldot * omega; |
239 |
scalecolor(ctmp, dtmp); |
240 |
addcolor(cval, ctmp); |
241 |
} |
242 |
|
243 |
/* Compute source contribution for BSDF (transmitted only) */ |
244 |
static void |
245 |
dir_btdf( |
246 |
COLOR cval, /* returned coefficient */ |
247 |
void *nnp, /* material data */ |
248 |
FVECT ldir, /* light source direction */ |
249 |
double omega /* light source size */ |
250 |
) |
251 |
{ |
252 |
BSDFDAT *np = (BSDFDAT *)nnp; |
253 |
double ldot; |
254 |
double dtmp; |
255 |
COLOR ctmp; |
256 |
|
257 |
setcolor(cval, .0, .0, .0); |
258 |
|
259 |
ldot = DOT(np->pnorm, ldir); |
260 |
|
261 |
if (ldot >= -FTINY) |
262 |
return; |
263 |
|
264 |
if (bright(np->tdiff) > FTINY) { |
265 |
/* |
266 |
* Compute added diffuse transmission. |
267 |
*/ |
268 |
copycolor(ctmp, np->tdiff); |
269 |
dtmp = -ldot * omega * (1.0/PI); |
270 |
scalecolor(ctmp, dtmp); |
271 |
addcolor(cval, ctmp); |
272 |
} |
273 |
/* |
274 |
* Compute scattering coefficient using BSDF. |
275 |
*/ |
276 |
if (!direct_bsdf_OK(ctmp, ldir, np)) |
277 |
return; |
278 |
/* full pattern on transmission */ |
279 |
multcolor(ctmp, np->pr->pcol); |
280 |
dtmp = -ldot * omega; |
281 |
scalecolor(ctmp, dtmp); |
282 |
addcolor(cval, ctmp); |
283 |
} |
284 |
|
285 |
/* Sample separate BSDF component */ |
286 |
static int |
287 |
sample_sdcomp(BSDFDAT *ndp, SDComponent *dcp, int usepat) |
288 |
{ |
289 |
int nstarget = 1; |
290 |
int nsent; |
291 |
SDError ec; |
292 |
SDValue bsv; |
293 |
double xrand; |
294 |
FVECT vsmp; |
295 |
RAY sr; |
296 |
/* multiple samples? */ |
297 |
if (specjitter > 1.5) { |
298 |
nstarget = specjitter*ndp->pr->rweight + .5; |
299 |
if (nstarget < 1) |
300 |
nstarget = 1; |
301 |
} |
302 |
/* run through our samples */ |
303 |
for (nsent = 0; nsent < nstarget; nsent++) { |
304 |
if (nstarget == 1) /* stratify random variable */ |
305 |
xrand = urand(ilhash(dimlist,ndims)+samplendx); |
306 |
else |
307 |
xrand = (nsent + frandom())/(double)nstarget; |
308 |
SDerrorDetail[0] = '\0'; /* sample direction & coef. */ |
309 |
bsdf_jitter(vsmp, ndp, 0); |
310 |
ec = SDsampComponent(&bsv, vsmp, xrand, dcp); |
311 |
if (ec) |
312 |
objerror(ndp->mp, USER, transSDError(ec)); |
313 |
if (bsv.cieY <= FTINY) /* zero component? */ |
314 |
break; |
315 |
/* map vector to world */ |
316 |
if (SDmapDir(sr.rdir, ndp->fromloc, vsmp) != SDEnone) |
317 |
break; |
318 |
/* spawn a specular ray */ |
319 |
if (nstarget > 1) |
320 |
bsv.cieY /= (double)nstarget; |
321 |
cvt_sdcolor(sr.rcoef, &bsv); /* use sample color */ |
322 |
if (usepat) /* apply pattern? */ |
323 |
multcolor(sr.rcoef, ndp->pr->pcol); |
324 |
if (rayorigin(&sr, SPECULAR, ndp->pr, sr.rcoef) < 0) { |
325 |
if (maxdepth > 0) |
326 |
break; |
327 |
continue; /* Russian roulette victim */ |
328 |
} |
329 |
/* need to offset origin? */ |
330 |
if (ndp->thick != 0 && ndp->pr->rod > 0 ^ vsmp[2] > 0) |
331 |
VSUM(sr.rorg, sr.rorg, ndp->pr->ron, -ndp->thick); |
332 |
rayvalue(&sr); /* send & evaluate sample */ |
333 |
multcolor(sr.rcol, sr.rcoef); |
334 |
addcolor(ndp->pr->rcol, sr.rcol); |
335 |
} |
336 |
return(nsent); |
337 |
} |
338 |
|
339 |
/* Sample non-diffuse components of BSDF */ |
340 |
static int |
341 |
sample_sdf(BSDFDAT *ndp, int sflags) |
342 |
{ |
343 |
int n, ntotal = 0; |
344 |
SDSpectralDF *dfp; |
345 |
COLORV *unsc; |
346 |
|
347 |
if (sflags == SDsampSpT) { |
348 |
unsc = ndp->tunsamp; |
349 |
dfp = ndp->sd->tf; |
350 |
cvt_sdcolor(unsc, &ndp->sd->tLamb); |
351 |
} else /* sflags == SDsampSpR */ { |
352 |
unsc = ndp->runsamp; |
353 |
if (ndp->pr->rod > 0) { |
354 |
dfp = ndp->sd->rf; |
355 |
cvt_sdcolor(unsc, &ndp->sd->rLambFront); |
356 |
} else { |
357 |
dfp = ndp->sd->rb; |
358 |
cvt_sdcolor(unsc, &ndp->sd->rLambBack); |
359 |
} |
360 |
} |
361 |
multcolor(unsc, ndp->pr->pcol); |
362 |
if (dfp == NULL) /* no specular component? */ |
363 |
return(0); |
364 |
/* below sampling threshold? */ |
365 |
if (dfp->maxHemi <= specthresh+FTINY) { |
366 |
if (dfp->maxHemi > FTINY) { /* XXX no color from BSDF */ |
367 |
FVECT vjit; |
368 |
double d; |
369 |
COLOR ctmp; |
370 |
bsdf_jitter(vjit, ndp, 1); |
371 |
d = SDdirectHemi(vjit, sflags, ndp->sd); |
372 |
if (sflags == SDsampSpT) { |
373 |
copycolor(ctmp, ndp->pr->pcol); |
374 |
scalecolor(ctmp, d); |
375 |
} else /* no pattern on reflection */ |
376 |
setcolor(ctmp, d, d, d); |
377 |
addcolor(unsc, ctmp); |
378 |
} |
379 |
return(0); |
380 |
} |
381 |
/* else need to sample */ |
382 |
dimlist[ndims++] = (int)(size_t)ndp->mp; |
383 |
ndims++; |
384 |
for (n = dfp->ncomp; n--; ) { /* loop over components */ |
385 |
dimlist[ndims-1] = n + 9438; |
386 |
ntotal += sample_sdcomp(ndp, &dfp->comp[n], sflags==SDsampSpT); |
387 |
} |
388 |
ndims -= 2; |
389 |
return(ntotal); |
390 |
} |
391 |
|
392 |
/* Color a ray that hit a BSDF material */ |
393 |
int |
394 |
m_bsdf(OBJREC *m, RAY *r) |
395 |
{ |
396 |
int hitfront; |
397 |
COLOR ctmp; |
398 |
SDError ec; |
399 |
FVECT upvec, vtmp; |
400 |
MFUNC *mf; |
401 |
BSDFDAT nd; |
402 |
/* check arguments */ |
403 |
if ((m->oargs.nsargs < 6) | (m->oargs.nfargs > 9) | |
404 |
(m->oargs.nfargs % 3)) |
405 |
objerror(m, USER, "bad # arguments"); |
406 |
/* record surface struck */ |
407 |
hitfront = (r->rod > 0); |
408 |
/* load cal file */ |
409 |
mf = getfunc(m, 5, 0x1d, 1); |
410 |
/* get thickness */ |
411 |
nd.thick = evalue(mf->ep[0]); |
412 |
if ((-FTINY <= nd.thick) & (nd.thick <= FTINY)) |
413 |
nd.thick = .0; |
414 |
/* check shadow */ |
415 |
if (r->crtype & SHADOW) { |
416 |
if (nd.thick != 0) |
417 |
raytrans(r); /* pass-through */ |
418 |
return(1); /* or shadow */ |
419 |
} |
420 |
/* check other rays to pass */ |
421 |
if (nd.thick != 0 && (!(r->crtype & (SPECULAR|AMBIENT)) || |
422 |
nd.thick > 0 ^ hitfront)) { |
423 |
raytrans(r); /* hide our proxy */ |
424 |
return(1); |
425 |
} |
426 |
/* get BSDF data */ |
427 |
nd.sd = loadBSDF(m->oargs.sarg[1]); |
428 |
/* diffuse reflectance */ |
429 |
if (hitfront) { |
430 |
if (m->oargs.nfargs < 3) |
431 |
setcolor(nd.rdiff, .0, .0, .0); |
432 |
else |
433 |
setcolor(nd.rdiff, m->oargs.farg[0], |
434 |
m->oargs.farg[1], |
435 |
m->oargs.farg[2]); |
436 |
} else { |
437 |
if (m->oargs.nfargs < 6) { /* check invisible backside */ |
438 |
if (!backvis && (nd.sd->rb == NULL) & |
439 |
(nd.sd->tf == NULL)) { |
440 |
SDfreeCache(nd.sd); |
441 |
raytrans(r); |
442 |
return(1); |
443 |
} |
444 |
setcolor(nd.rdiff, .0, .0, .0); |
445 |
} else |
446 |
setcolor(nd.rdiff, m->oargs.farg[3], |
447 |
m->oargs.farg[4], |
448 |
m->oargs.farg[5]); |
449 |
} |
450 |
/* diffuse transmittance */ |
451 |
if (m->oargs.nfargs < 9) |
452 |
setcolor(nd.tdiff, .0, .0, .0); |
453 |
else |
454 |
setcolor(nd.tdiff, m->oargs.farg[6], |
455 |
m->oargs.farg[7], |
456 |
m->oargs.farg[8]); |
457 |
nd.mp = m; |
458 |
nd.pr = r; |
459 |
/* get modifiers */ |
460 |
raytexture(r, m->omod); |
461 |
/* modify diffuse values */ |
462 |
multcolor(nd.rdiff, r->pcol); |
463 |
multcolor(nd.tdiff, r->pcol); |
464 |
/* get up vector */ |
465 |
upvec[0] = evalue(mf->ep[1]); |
466 |
upvec[1] = evalue(mf->ep[2]); |
467 |
upvec[2] = evalue(mf->ep[3]); |
468 |
/* return to world coords */ |
469 |
if (mf->f != &unitxf) { |
470 |
multv3(upvec, upvec, mf->f->xfm); |
471 |
nd.thick *= mf->f->sca; |
472 |
} |
473 |
raynormal(nd.pnorm, r); |
474 |
/* compute local BSDF xform */ |
475 |
ec = SDcompXform(nd.toloc, nd.pnorm, upvec); |
476 |
if (!ec) { |
477 |
nd.vray[0] = -r->rdir[0]; |
478 |
nd.vray[1] = -r->rdir[1]; |
479 |
nd.vray[2] = -r->rdir[2]; |
480 |
ec = SDmapDir(nd.vray, nd.toloc, nd.vray); |
481 |
} |
482 |
if (!ec) |
483 |
ec = SDinvXform(nd.fromloc, nd.toloc); |
484 |
/* determine BSDF resolution */ |
485 |
if (!ec) |
486 |
ec = SDsizeBSDF(nd.sr_vpsa, nd.vray, NULL, |
487 |
SDqueryMin+SDqueryMax, nd.sd); |
488 |
nd.thru_psa = .0; |
489 |
if (!ec && nd.thick != 0 && r->crtype & (SPECULAR|AMBIENT)) { |
490 |
FVECT vthru; |
491 |
vthru[0] = -nd.vray[0]; |
492 |
vthru[1] = -nd.vray[1]; |
493 |
vthru[2] = -nd.vray[2]; |
494 |
ec = SDsizeBSDF(&nd.thru_psa, nd.vray, vthru, |
495 |
SDqueryMin, nd.sd); |
496 |
} |
497 |
if (ec) { |
498 |
objerror(m, WARNING, transSDError(ec)); |
499 |
SDfreeCache(nd.sd); |
500 |
return(1); |
501 |
} |
502 |
nd.sr_vpsa[0] = sqrt(nd.sr_vpsa[0]); |
503 |
nd.sr_vpsa[1] = sqrt(nd.sr_vpsa[1]); |
504 |
if (!hitfront) { /* perturb normal towards hit */ |
505 |
nd.pnorm[0] = -nd.pnorm[0]; |
506 |
nd.pnorm[1] = -nd.pnorm[1]; |
507 |
nd.pnorm[2] = -nd.pnorm[2]; |
508 |
} |
509 |
/* sample reflection */ |
510 |
sample_sdf(&nd, SDsampSpR); |
511 |
/* sample transmission */ |
512 |
sample_sdf(&nd, SDsampSpT); |
513 |
/* compute indirect diffuse */ |
514 |
copycolor(ctmp, nd.rdiff); |
515 |
addcolor(ctmp, nd.runsamp); |
516 |
if (bright(ctmp) > FTINY) { /* ambient from reflection */ |
517 |
if (!hitfront) |
518 |
flipsurface(r); |
519 |
multambient(ctmp, r, nd.pnorm); |
520 |
addcolor(r->rcol, ctmp); |
521 |
if (!hitfront) |
522 |
flipsurface(r); |
523 |
} |
524 |
copycolor(ctmp, nd.tdiff); |
525 |
addcolor(ctmp, nd.tunsamp); |
526 |
if (bright(ctmp) > FTINY) { /* ambient from other side */ |
527 |
FVECT bnorm; |
528 |
if (hitfront) |
529 |
flipsurface(r); |
530 |
bnorm[0] = -nd.pnorm[0]; |
531 |
bnorm[1] = -nd.pnorm[1]; |
532 |
bnorm[2] = -nd.pnorm[2]; |
533 |
if (nd.thick != 0) { /* proxy with offset? */ |
534 |
VCOPY(vtmp, r->rop); |
535 |
VSUM(r->rop, vtmp, r->ron, -nd.thick); |
536 |
multambient(ctmp, r, bnorm); |
537 |
VCOPY(r->rop, vtmp); |
538 |
} else |
539 |
multambient(ctmp, r, bnorm); |
540 |
addcolor(r->rcol, ctmp); |
541 |
if (hitfront) |
542 |
flipsurface(r); |
543 |
} |
544 |
/* add direct component */ |
545 |
if ((bright(nd.tdiff) <= FTINY) & (nd.sd->tf == NULL)) { |
546 |
direct(r, dir_brdf, &nd); /* reflection only */ |
547 |
} else if (nd.thick == 0) { |
548 |
direct(r, dir_bsdf, &nd); /* thin surface scattering */ |
549 |
} else { |
550 |
direct(r, dir_brdf, &nd); /* reflection first */ |
551 |
VCOPY(vtmp, r->rop); /* offset for transmitted */ |
552 |
VSUM(r->rop, vtmp, r->ron, -nd.thick); |
553 |
direct(r, dir_btdf, &nd); /* separate transmission */ |
554 |
VCOPY(r->rop, vtmp); |
555 |
} |
556 |
/* clean up */ |
557 |
SDfreeCache(nd.sd); |
558 |
return(1); |
559 |
} |