| 1 |
#ifndef lint |
| 2 |
static const char RCSid[] = "$Id: m_bsdf.c,v 2.6 2011/02/20 17:43:43 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 |
| 52 |
* 0 |
| 53 |
* 0|3|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; /* sqrt of BSDF projected solid angle */ |
| 71 |
RREAL toloc[3][3]; /* world to local BSDF coords */ |
| 72 |
RREAL fromloc[3][3]; /* local BSDF coords to world */ |
| 73 |
double thick; /* surface thickness */ |
| 74 |
SDData *sd; /* loaded BSDF data */ |
| 75 |
COLOR runsamp; /* BSDF hemispherical reflection */ |
| 76 |
COLOR rdiff; /* added diffuse reflection */ |
| 77 |
COLOR tunsamp; /* BSDF hemispherical transmission */ |
| 78 |
COLOR tdiff; /* added diffuse transmission */ |
| 79 |
} BSDFDAT; /* BSDF material data */ |
| 80 |
|
| 81 |
#define cvt_sdcolor(cv, svp) ccy2rgb(&(svp)->spec, (svp)->cieY, cv) |
| 82 |
|
| 83 |
/* Jitter ray sample according to projected solid angle and specjitter */ |
| 84 |
static void |
| 85 |
bsdf_jitter(FVECT vres, BSDFDAT *ndp) |
| 86 |
{ |
| 87 |
double sr_psa = ndp->sr_vpsa; |
| 88 |
|
| 89 |
VCOPY(vres, ndp->vray); |
| 90 |
if (specjitter < 1.) |
| 91 |
sr_psa *= specjitter; |
| 92 |
if (sr_psa <= FTINY) |
| 93 |
return; |
| 94 |
vres[0] += sr_psa*(.5 - frandom()); |
| 95 |
vres[1] += sr_psa*(.5 - frandom()); |
| 96 |
normalize(vres); |
| 97 |
} |
| 98 |
|
| 99 |
/* Evaluate BSDF for direct component, returning true if OK to proceed */ |
| 100 |
static int |
| 101 |
direct_bsdf_OK(COLOR cval, FVECT ldir, BSDFDAT *ndp) |
| 102 |
{ |
| 103 |
FVECT vsrc, vjit; |
| 104 |
SDValue sv; |
| 105 |
SDError ec; |
| 106 |
/* transform source direction */ |
| 107 |
if (SDmapDir(vsrc, ndp->toloc, ldir) != SDEnone) |
| 108 |
return(0); |
| 109 |
/* jitter query direction */ |
| 110 |
bsdf_jitter(vjit, ndp); |
| 111 |
/* avoid indirect over-counting */ |
| 112 |
if (ndp->thick != .0 && ndp->pr->crtype & (SPECULAR|AMBIENT) && |
| 113 |
vsrc[2] > .0 ^ vjit[2] > .0) { |
| 114 |
double dx = vsrc[0] + vjit[0]; |
| 115 |
double dy = vsrc[1] + vjit[1]; |
| 116 |
if (dx*dx + dy*dy <= ndp->sr_vpsa*ndp->sr_vpsa) |
| 117 |
return(0); |
| 118 |
} |
| 119 |
ec = SDevalBSDF(&sv, vjit, vsrc, ndp->sd); |
| 120 |
if (ec) |
| 121 |
objerror(ndp->mp, USER, transSDError(ec)); |
| 122 |
|
| 123 |
if (sv.cieY <= FTINY) /* not worth using? */ |
| 124 |
return(0); |
| 125 |
/* else we're good to go */ |
| 126 |
cvt_sdcolor(cval, &sv); |
| 127 |
return(1); |
| 128 |
} |
| 129 |
|
| 130 |
/* Compute source contribution for BSDF (reflected & transmitted) */ |
| 131 |
static void |
| 132 |
dir_bsdf( |
| 133 |
COLOR cval, /* returned coefficient */ |
| 134 |
void *nnp, /* material data */ |
| 135 |
FVECT ldir, /* light source direction */ |
| 136 |
double omega /* light source size */ |
| 137 |
) |
| 138 |
{ |
| 139 |
BSDFDAT *np = (BSDFDAT *)nnp; |
| 140 |
double ldot; |
| 141 |
double dtmp; |
| 142 |
COLOR ctmp; |
| 143 |
|
| 144 |
setcolor(cval, .0, .0, .0); |
| 145 |
|
| 146 |
ldot = DOT(np->pnorm, ldir); |
| 147 |
if ((-FTINY <= ldot) & (ldot <= FTINY)) |
| 148 |
return; |
| 149 |
|
| 150 |
if (ldot > .0 && bright(np->rdiff) > FTINY) { |
| 151 |
/* |
| 152 |
* Compute added diffuse reflected component. |
| 153 |
*/ |
| 154 |
copycolor(ctmp, np->rdiff); |
| 155 |
dtmp = ldot * omega * (1./PI); |
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scalecolor(ctmp, dtmp); |
| 157 |
addcolor(cval, ctmp); |
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} |
| 159 |
if (ldot < .0 && bright(np->tdiff) > FTINY) { |
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/* |
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* Compute added diffuse transmission. |
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*/ |
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copycolor(ctmp, np->tdiff); |
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dtmp = -ldot * omega * (1.0/PI); |
| 165 |
scalecolor(ctmp, dtmp); |
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addcolor(cval, ctmp); |
| 167 |
} |
| 168 |
/* |
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* Compute scattering coefficient using BSDF. |
| 170 |
*/ |
| 171 |
if (!direct_bsdf_OK(ctmp, ldir, np)) |
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return; |
| 173 |
if (ldot > .0) { /* pattern only diffuse reflection */ |
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COLOR ctmp1, ctmp2; |
| 175 |
dtmp = (np->pr->rod > .0) ? np->sd->rLambFront.cieY |
| 176 |
: np->sd->rLambBack.cieY; |
| 177 |
/* diffuse fraction */ |
| 178 |
dtmp /= PI * bright(ctmp); |
| 179 |
copycolor(ctmp2, np->pr->pcol); |
| 180 |
scalecolor(ctmp2, dtmp); |
| 181 |
setcolor(ctmp1, 1.-dtmp, 1.-dtmp, 1.-dtmp); |
| 182 |
addcolor(ctmp1, ctmp2); |
| 183 |
multcolor(ctmp, ctmp1); /* apply derated pattern */ |
| 184 |
dtmp = ldot * omega; |
| 185 |
} else { /* full pattern on transmission */ |
| 186 |
multcolor(ctmp, np->pr->pcol); |
| 187 |
dtmp = -ldot * omega; |
| 188 |
} |
| 189 |
scalecolor(ctmp, dtmp); |
| 190 |
addcolor(cval, ctmp); |
| 191 |
} |
| 192 |
|
| 193 |
/* Compute source contribution for BSDF (reflected only) */ |
| 194 |
static void |
| 195 |
dir_brdf( |
| 196 |
COLOR cval, /* returned coefficient */ |
| 197 |
void *nnp, /* material data */ |
| 198 |
FVECT ldir, /* light source direction */ |
| 199 |
double omega /* light source size */ |
| 200 |
) |
| 201 |
{ |
| 202 |
BSDFDAT *np = (BSDFDAT *)nnp; |
| 203 |
double ldot; |
| 204 |
double dtmp; |
| 205 |
COLOR ctmp, ctmp1, ctmp2; |
| 206 |
|
| 207 |
setcolor(cval, .0, .0, .0); |
| 208 |
|
| 209 |
ldot = DOT(np->pnorm, ldir); |
| 210 |
|
| 211 |
if (ldot <= FTINY) |
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return; |
| 213 |
|
| 214 |
if (bright(np->rdiff) > FTINY) { |
| 215 |
/* |
| 216 |
* Compute added diffuse reflected component. |
| 217 |
*/ |
| 218 |
copycolor(ctmp, np->rdiff); |
| 219 |
dtmp = ldot * omega * (1./PI); |
| 220 |
scalecolor(ctmp, dtmp); |
| 221 |
addcolor(cval, ctmp); |
| 222 |
} |
| 223 |
/* |
| 224 |
* Compute reflection coefficient using BSDF. |
| 225 |
*/ |
| 226 |
if (!direct_bsdf_OK(ctmp, ldir, np)) |
| 227 |
return; |
| 228 |
/* pattern only diffuse reflection */ |
| 229 |
dtmp = (np->pr->rod > .0) ? np->sd->rLambFront.cieY |
| 230 |
: np->sd->rLambBack.cieY; |
| 231 |
dtmp /= PI * bright(ctmp); /* diffuse fraction */ |
| 232 |
copycolor(ctmp2, np->pr->pcol); |
| 233 |
scalecolor(ctmp2, dtmp); |
| 234 |
setcolor(ctmp1, 1.-dtmp, 1.-dtmp, 1.-dtmp); |
| 235 |
addcolor(ctmp1, ctmp2); |
| 236 |
multcolor(ctmp, ctmp1); /* apply derated pattern */ |
| 237 |
dtmp = ldot * omega; |
| 238 |
scalecolor(ctmp, dtmp); |
| 239 |
addcolor(cval, ctmp); |
| 240 |
} |
| 241 |
|
| 242 |
/* Compute source contribution for BSDF (transmitted only) */ |
| 243 |
static void |
| 244 |
dir_btdf( |
| 245 |
COLOR cval, /* returned coefficient */ |
| 246 |
void *nnp, /* material data */ |
| 247 |
FVECT ldir, /* light source direction */ |
| 248 |
double omega /* light source size */ |
| 249 |
) |
| 250 |
{ |
| 251 |
BSDFDAT *np = (BSDFDAT *)nnp; |
| 252 |
double ldot; |
| 253 |
double dtmp; |
| 254 |
COLOR ctmp; |
| 255 |
|
| 256 |
setcolor(cval, .0, .0, .0); |
| 257 |
|
| 258 |
ldot = DOT(np->pnorm, ldir); |
| 259 |
|
| 260 |
if (ldot >= -FTINY) |
| 261 |
return; |
| 262 |
|
| 263 |
if (bright(np->tdiff) > FTINY) { |
| 264 |
/* |
| 265 |
* Compute added diffuse transmission. |
| 266 |
*/ |
| 267 |
copycolor(ctmp, np->tdiff); |
| 268 |
dtmp = -ldot * omega * (1.0/PI); |
| 269 |
scalecolor(ctmp, dtmp); |
| 270 |
addcolor(cval, ctmp); |
| 271 |
} |
| 272 |
/* |
| 273 |
* Compute scattering coefficient using BSDF. |
| 274 |
*/ |
| 275 |
if (!direct_bsdf_OK(ctmp, ldir, np)) |
| 276 |
return; |
| 277 |
/* full pattern on transmission */ |
| 278 |
multcolor(ctmp, np->pr->pcol); |
| 279 |
dtmp = -ldot * omega; |
| 280 |
scalecolor(ctmp, dtmp); |
| 281 |
addcolor(cval, ctmp); |
| 282 |
} |
| 283 |
|
| 284 |
/* Sample separate BSDF component */ |
| 285 |
static int |
| 286 |
sample_sdcomp(BSDFDAT *ndp, SDComponent *dcp, int usepat) |
| 287 |
{ |
| 288 |
int nstarget = 1; |
| 289 |
int nsent = 0; |
| 290 |
SDError ec; |
| 291 |
SDValue bsv; |
| 292 |
double sthick; |
| 293 |
FVECT vjit, vsmp; |
| 294 |
RAY sr; |
| 295 |
int ntrials; |
| 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 trials */ |
| 303 |
for (ntrials = 0; nsent < nstarget && ntrials < 9*nstarget; ntrials++) { |
| 304 |
SDerrorDetail[0] = '\0'; |
| 305 |
/* sample direction & coef. */ |
| 306 |
bsdf_jitter(vjit, ndp); |
| 307 |
ec = SDsampComponent(&bsv, vsmp, vjit, ntrials ? frandom() |
| 308 |
: urand(ilhash(dimlist,ndims)+samplendx), dcp); |
| 309 |
if (ec) |
| 310 |
objerror(ndp->mp, USER, transSDError(ec)); |
| 311 |
/* zero component? */ |
| 312 |
if (bsv.cieY <= FTINY) |
| 313 |
break; |
| 314 |
/* map vector to world */ |
| 315 |
if (SDmapDir(sr.rdir, ndp->fromloc, vsmp) != SDEnone) |
| 316 |
break; |
| 317 |
/* unintentional penetration? */ |
| 318 |
if (DOT(sr.rdir, ndp->pr->ron) > .0 ^ vsmp[2] > .0) |
| 319 |
continue; |
| 320 |
/* spawn a specular ray */ |
| 321 |
if (nstarget > 1) |
| 322 |
bsv.cieY /= (double)nstarget; |
| 323 |
cvt_sdcolor(sr.rcoef, &bsv); /* use color */ |
| 324 |
if (usepat) /* pattern on transmission */ |
| 325 |
multcolor(sr.rcoef, ndp->pr->pcol); |
| 326 |
if (rayorigin(&sr, SPECULAR, ndp->pr, sr.rcoef) < 0) { |
| 327 |
if (maxdepth > 0) |
| 328 |
break; |
| 329 |
++nsent; /* Russian roulette victim */ |
| 330 |
continue; |
| 331 |
} |
| 332 |
/* need to offset origin? */ |
| 333 |
if (ndp->thick != .0 && ndp->pr->rod > .0 ^ vsmp[2] > .0) |
| 334 |
VSUM(sr.rorg, sr.rorg, ndp->pr->ron, -ndp->thick); |
| 335 |
rayvalue(&sr); /* send & evaluate sample */ |
| 336 |
multcolor(sr.rcol, sr.rcoef); |
| 337 |
addcolor(ndp->pr->rcol, sr.rcol); |
| 338 |
++nsent; |
| 339 |
} |
| 340 |
return(nsent); |
| 341 |
} |
| 342 |
|
| 343 |
/* Sample non-diffuse components of BSDF */ |
| 344 |
static int |
| 345 |
sample_sdf(BSDFDAT *ndp, int sflags) |
| 346 |
{ |
| 347 |
int n, ntotal = 0; |
| 348 |
SDSpectralDF *dfp; |
| 349 |
COLORV *unsc; |
| 350 |
|
| 351 |
if (sflags == SDsampSpT) { |
| 352 |
unsc = ndp->tunsamp; |
| 353 |
dfp = ndp->sd->tf; |
| 354 |
cvt_sdcolor(unsc, &ndp->sd->tLamb); |
| 355 |
} else /* sflags == SDsampSpR */ { |
| 356 |
unsc = ndp->runsamp; |
| 357 |
if (ndp->pr->rod > .0) { |
| 358 |
dfp = ndp->sd->rf; |
| 359 |
cvt_sdcolor(unsc, &ndp->sd->rLambFront); |
| 360 |
} else { |
| 361 |
dfp = ndp->sd->rb; |
| 362 |
cvt_sdcolor(unsc, &ndp->sd->rLambBack); |
| 363 |
} |
| 364 |
} |
| 365 |
multcolor(unsc, ndp->pr->pcol); |
| 366 |
if (dfp == NULL) /* no specular component? */ |
| 367 |
return(0); |
| 368 |
/* below sampling threshold? */ |
| 369 |
if (dfp->maxHemi <= specthresh+FTINY) { |
| 370 |
if (dfp->maxHemi > FTINY) { /* XXX no color from BSDF */ |
| 371 |
FVECT vjit; |
| 372 |
double d; |
| 373 |
COLOR ctmp; |
| 374 |
bsdf_jitter(vjit, ndp); |
| 375 |
d = SDdirectHemi(vjit, sflags, ndp->sd); |
| 376 |
if (sflags == SDsampSpT) { |
| 377 |
copycolor(ctmp, ndp->pr->pcol); |
| 378 |
scalecolor(ctmp, d); |
| 379 |
} else /* no pattern on reflection */ |
| 380 |
setcolor(ctmp, d, d, d); |
| 381 |
addcolor(unsc, ctmp); |
| 382 |
} |
| 383 |
return(0); |
| 384 |
} |
| 385 |
/* else need to sample */ |
| 386 |
dimlist[ndims++] = (int)(size_t)ndp->mp; |
| 387 |
ndims++; |
| 388 |
for (n = dfp->ncomp; n--; ) { /* loop over components */ |
| 389 |
dimlist[ndims-1] = n + 9438; |
| 390 |
ntotal += sample_sdcomp(ndp, &dfp->comp[n], sflags==SDsampSpT); |
| 391 |
} |
| 392 |
ndims -= 2; |
| 393 |
return(ntotal); |
| 394 |
} |
| 395 |
|
| 396 |
/* Color a ray that hit a BSDF material */ |
| 397 |
int |
| 398 |
m_bsdf(OBJREC *m, RAY *r) |
| 399 |
{ |
| 400 |
int hitfront; |
| 401 |
COLOR ctmp; |
| 402 |
SDError ec; |
| 403 |
FVECT upvec, vtmp; |
| 404 |
MFUNC *mf; |
| 405 |
BSDFDAT nd; |
| 406 |
/* check arguments */ |
| 407 |
if ((m->oargs.nsargs < 6) | (m->oargs.nfargs > 9) | |
| 408 |
(m->oargs.nfargs % 3)) |
| 409 |
objerror(m, USER, "bad # arguments"); |
| 410 |
/* record surface struck */ |
| 411 |
hitfront = (r->rod > .0); |
| 412 |
/* load cal file */ |
| 413 |
mf = getfunc(m, 5, 0x1d, 1); |
| 414 |
/* get thickness */ |
| 415 |
nd.thick = evalue(mf->ep[0]); |
| 416 |
if ((-FTINY <= nd.thick) & (nd.thick <= FTINY)) |
| 417 |
nd.thick = .0; |
| 418 |
/* check shadow */ |
| 419 |
if (r->crtype & SHADOW) { |
| 420 |
if (nd.thick != .0) |
| 421 |
raytrans(r); /* pass-through */ |
| 422 |
return(1); /* or shadow */ |
| 423 |
} |
| 424 |
/* check other rays to pass */ |
| 425 |
if (nd.thick != .0 && (!(r->crtype & (SPECULAR|AMBIENT)) || |
| 426 |
nd.thick > .0 ^ hitfront)) { |
| 427 |
raytrans(r); /* hide our proxy */ |
| 428 |
return(1); |
| 429 |
} |
| 430 |
/* get BSDF data */ |
| 431 |
nd.sd = loadBSDF(m->oargs.sarg[1]); |
| 432 |
/* diffuse reflectance */ |
| 433 |
if (hitfront) { |
| 434 |
if (m->oargs.nfargs < 3) |
| 435 |
setcolor(nd.rdiff, .0, .0, .0); |
| 436 |
else |
| 437 |
setcolor(nd.rdiff, m->oargs.farg[0], |
| 438 |
m->oargs.farg[1], |
| 439 |
m->oargs.farg[2]); |
| 440 |
} else { |
| 441 |
if (m->oargs.nfargs < 6) { /* check invisible backside */ |
| 442 |
if (!backvis && (nd.sd->rb == NULL) & |
| 443 |
(nd.sd->tf == NULL)) { |
| 444 |
SDfreeCache(nd.sd); |
| 445 |
raytrans(r); |
| 446 |
return(1); |
| 447 |
} |
| 448 |
setcolor(nd.rdiff, .0, .0, .0); |
| 449 |
} else |
| 450 |
setcolor(nd.rdiff, m->oargs.farg[3], |
| 451 |
m->oargs.farg[4], |
| 452 |
m->oargs.farg[5]); |
| 453 |
} |
| 454 |
/* diffuse transmittance */ |
| 455 |
if (m->oargs.nfargs < 9) |
| 456 |
setcolor(nd.tdiff, .0, .0, .0); |
| 457 |
else |
| 458 |
setcolor(nd.tdiff, m->oargs.farg[6], |
| 459 |
m->oargs.farg[7], |
| 460 |
m->oargs.farg[8]); |
| 461 |
nd.mp = m; |
| 462 |
nd.pr = r; |
| 463 |
/* get modifiers */ |
| 464 |
raytexture(r, m->omod); |
| 465 |
/* modify diffuse values */ |
| 466 |
multcolor(nd.rdiff, r->pcol); |
| 467 |
multcolor(nd.tdiff, r->pcol); |
| 468 |
/* get up vector */ |
| 469 |
upvec[0] = evalue(mf->ep[1]); |
| 470 |
upvec[1] = evalue(mf->ep[2]); |
| 471 |
upvec[2] = evalue(mf->ep[3]); |
| 472 |
/* return to world coords */ |
| 473 |
if (mf->f != &unitxf) { |
| 474 |
multv3(upvec, upvec, mf->f->xfm); |
| 475 |
nd.thick *= mf->f->sca; |
| 476 |
} |
| 477 |
raynormal(nd.pnorm, r); |
| 478 |
/* compute local BSDF xform */ |
| 479 |
ec = SDcompXform(nd.toloc, nd.pnorm, upvec); |
| 480 |
if (!ec) { |
| 481 |
nd.vray[0] = -r->rdir[0]; |
| 482 |
nd.vray[1] = -r->rdir[1]; |
| 483 |
nd.vray[2] = -r->rdir[2]; |
| 484 |
ec = SDmapDir(nd.vray, nd.toloc, nd.vray); |
| 485 |
} |
| 486 |
if (!ec) |
| 487 |
ec = SDinvXform(nd.fromloc, nd.toloc); |
| 488 |
/* determine BSDF resolution */ |
| 489 |
if (!ec) |
| 490 |
ec = SDsizeBSDF(&nd.sr_vpsa, nd.vray, SDqueryMin, nd.sd); |
| 491 |
if (!ec) |
| 492 |
nd.sr_vpsa = sqrt(nd.sr_vpsa); |
| 493 |
else { |
| 494 |
objerror(m, WARNING, transSDError(ec)); |
| 495 |
SDfreeCache(nd.sd); |
| 496 |
return(1); |
| 497 |
} |
| 498 |
if (!hitfront) { /* perturb normal towards hit */ |
| 499 |
nd.pnorm[0] = -nd.pnorm[0]; |
| 500 |
nd.pnorm[1] = -nd.pnorm[1]; |
| 501 |
nd.pnorm[2] = -nd.pnorm[2]; |
| 502 |
} |
| 503 |
/* sample reflection */ |
| 504 |
sample_sdf(&nd, SDsampSpR); |
| 505 |
/* sample transmission */ |
| 506 |
sample_sdf(&nd, SDsampSpT); |
| 507 |
/* compute indirect diffuse */ |
| 508 |
copycolor(ctmp, nd.rdiff); |
| 509 |
addcolor(ctmp, nd.runsamp); |
| 510 |
if (bright(ctmp) > FTINY) { /* ambient from reflection */ |
| 511 |
if (!hitfront) |
| 512 |
flipsurface(r); |
| 513 |
multambient(ctmp, r, nd.pnorm); |
| 514 |
addcolor(r->rcol, ctmp); |
| 515 |
if (!hitfront) |
| 516 |
flipsurface(r); |
| 517 |
} |
| 518 |
copycolor(ctmp, nd.tdiff); |
| 519 |
addcolor(ctmp, nd.tunsamp); |
| 520 |
if (bright(ctmp) > FTINY) { /* ambient from other side */ |
| 521 |
FVECT bnorm; |
| 522 |
if (hitfront) |
| 523 |
flipsurface(r); |
| 524 |
bnorm[0] = -nd.pnorm[0]; |
| 525 |
bnorm[1] = -nd.pnorm[1]; |
| 526 |
bnorm[2] = -nd.pnorm[2]; |
| 527 |
if (nd.thick != .0) { /* proxy with offset? */ |
| 528 |
VCOPY(vtmp, r->rop); |
| 529 |
VSUM(r->rop, vtmp, r->ron, -nd.thick); |
| 530 |
multambient(ctmp, r, bnorm); |
| 531 |
VCOPY(r->rop, vtmp); |
| 532 |
} else |
| 533 |
multambient(ctmp, r, bnorm); |
| 534 |
addcolor(r->rcol, ctmp); |
| 535 |
if (hitfront) |
| 536 |
flipsurface(r); |
| 537 |
} |
| 538 |
/* add direct component */ |
| 539 |
if ((bright(nd.tdiff) <= FTINY) & (nd.sd->tf == NULL)) { |
| 540 |
direct(r, dir_brdf, &nd); /* reflection only */ |
| 541 |
} else if (nd.thick == .0) { |
| 542 |
direct(r, dir_bsdf, &nd); /* thin surface scattering */ |
| 543 |
} else { |
| 544 |
direct(r, dir_brdf, &nd); /* reflection first */ |
| 545 |
VCOPY(vtmp, r->rop); /* offset for transmitted */ |
| 546 |
VSUM(r->rop, vtmp, r->ron, -nd.thick); |
| 547 |
direct(r, dir_btdf, &nd); /* separate transmission */ |
| 548 |
VCOPY(r->rop, vtmp); |
| 549 |
} |
| 550 |
/* clean up */ |
| 551 |
SDfreeCache(nd.sd); |
| 552 |
return(1); |
| 553 |
} |
