| 1 |
#ifndef lint |
| 2 |
static const char RCSid[] = "$Id: m_bsdf.c,v 2.63 2021/03/27 20:08:58 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 "otypes.h" |
| 12 |
#include "ambient.h" |
| 13 |
#include "source.h" |
| 14 |
#include "func.h" |
| 15 |
#include "bsdf.h" |
| 16 |
#include "random.h" |
| 17 |
#include "pmapmat.h" |
| 18 |
|
| 19 |
/* |
| 20 |
* Arguments to this material include optional diffuse colors. |
| 21 |
* String arguments include the BSDF and function files. |
| 22 |
* For the MAT_BSDF type, a non-zero thickness causes the useful behavior |
| 23 |
* of translating transmitted rays this distance beneath the surface |
| 24 |
* (opposite the surface normal) to bypass any intervening geometry. |
| 25 |
* Translation only affects scattered, non-source-directed samples. |
| 26 |
* A non-zero thickness has the further side-effect that an unscattered |
| 27 |
* (view) ray will pass right through our material, making the BSDF |
| 28 |
* surface invisible and showing the proxied geometry instead. Thickness |
| 29 |
* has the further effect of turning off reflection on the reverse side so |
| 30 |
* rays 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 |
* For the MAT_ABSDF type, we check for a strong "through" component. |
| 40 |
* Such a component will cause direct rays to pass through unscattered. |
| 41 |
* A separate test prevents over-counting by dropping samples that are |
| 42 |
* too close to this "through" direction. BSDFs with such a through direction |
| 43 |
* will also have a view component, meaning they are somewhat see-through. |
| 44 |
* A MAT_BSDF type with zero thickness behaves the same as a MAT_ABSDF |
| 45 |
* type with no strong through component. |
| 46 |
* The "up" vector for the BSDF is given by three variables, defined |
| 47 |
* (along with the thickness) by the named function file, or '.' if none. |
| 48 |
* Together with the surface normal, this defines the local coordinate |
| 49 |
* system for the BSDF. |
| 50 |
* We do not reorient the surface, so if the BSDF has no back-side |
| 51 |
* reflectance and none is given in the real arguments, a BSDF surface |
| 52 |
* with zero thickness will appear black when viewed from behind |
| 53 |
* unless backface visibility is on, when it becomes invisible. |
| 54 |
* The diffuse arguments are added to components in the BSDF file, |
| 55 |
* not multiplied. However, patterns affect this material as a multiplier |
| 56 |
* on everything except non-diffuse reflection. |
| 57 |
* |
| 58 |
* Arguments for MAT_ABSDF are: |
| 59 |
* 5+ BSDFfile ux uy uz funcfile transform |
| 60 |
* 0 |
| 61 |
* 0|3|6|9 rdf gdf bdf |
| 62 |
* rdb gdb bdb |
| 63 |
* rdt gdt bdt |
| 64 |
* |
| 65 |
* Arguments for MAT_BSDF are: |
| 66 |
* 6+ thick BSDFfile ux uy uz funcfile transform |
| 67 |
* 0 |
| 68 |
* 0|3|6|9 rdf gdf bdf |
| 69 |
* rdb gdb bdb |
| 70 |
* rdt gdt bdt |
| 71 |
*/ |
| 72 |
|
| 73 |
/* |
| 74 |
* Note that our reverse ray-tracing process means that the positions |
| 75 |
* of incoming and outgoing vectors may be reversed in our calls |
| 76 |
* to the BSDF library. This is usually fine, since the bidirectional nature |
| 77 |
* of the BSDF (that's what the 'B' stands for) means it all works out. |
| 78 |
*/ |
| 79 |
|
| 80 |
typedef struct { |
| 81 |
OBJREC *mp; /* material pointer */ |
| 82 |
RAY *pr; /* intersected ray */ |
| 83 |
FVECT pnorm; /* perturbed surface normal */ |
| 84 |
FVECT vray; /* local outgoing (return) vector */ |
| 85 |
double sr_vpsa[2]; /* sqrt of BSDF projected solid angle extrema */ |
| 86 |
RREAL toloc[3][3]; /* world to local BSDF coords */ |
| 87 |
RREAL fromloc[3][3]; /* local BSDF coords to world */ |
| 88 |
double thick; /* surface thickness */ |
| 89 |
COLOR cthru; /* "through" component for MAT_ABSDF */ |
| 90 |
COLOR cthru_surr; /* surround for "through" component */ |
| 91 |
SDData *sd; /* loaded BSDF data */ |
| 92 |
COLOR rdiff; /* diffuse reflection */ |
| 93 |
COLOR runsamp; /* BSDF hemispherical reflection */ |
| 94 |
COLOR tdiff; /* diffuse transmission */ |
| 95 |
COLOR tunsamp; /* BSDF hemispherical transmission */ |
| 96 |
} BSDFDAT; /* BSDF material data */ |
| 97 |
|
| 98 |
#define cvt_sdcolor(cv, svp) ccy2rgb(&(svp)->spec, (svp)->cieY, cv) |
| 99 |
|
| 100 |
typedef struct { |
| 101 |
double vy; /* brightness (for sorting) */ |
| 102 |
FVECT tdir; /* through sample direction (normalized) */ |
| 103 |
COLOR vcol; /* BTDF color */ |
| 104 |
} PEAKSAMP; /* BTDF peak sample */ |
| 105 |
|
| 106 |
/* Comparison function to put near-peak values in descending order */ |
| 107 |
static int |
| 108 |
cmp_psamp(const void *p1, const void *p2) |
| 109 |
{ |
| 110 |
double diff = (*(const PEAKSAMP *)p1).vy - (*(const PEAKSAMP *)p2).vy; |
| 111 |
if (diff > 0) return(-1); |
| 112 |
if (diff < 0) return(1); |
| 113 |
return(0); |
| 114 |
} |
| 115 |
|
| 116 |
/* Compute "through" component color for MAT_ABSDF */ |
| 117 |
static void |
| 118 |
compute_through(BSDFDAT *ndp) |
| 119 |
{ |
| 120 |
#define NDIR2CHECK 29 |
| 121 |
static const float dir2check[NDIR2CHECK][2] = { |
| 122 |
{0, 0}, {-0.6, 0}, {0, 0.6}, |
| 123 |
{0, -0.6}, {0.6, 0}, {-0.6, 0.6}, |
| 124 |
{-0.6, -0.6}, {0.6, 0.6}, {0.6, -0.6}, |
| 125 |
{-1.2, 0}, {0, 1.2}, {0, -1.2}, |
| 126 |
{1.2, 0}, {-1.2, 1.2}, {-1.2, -1.2}, |
| 127 |
{1.2, 1.2}, {1.2, -1.2}, {-1.8, 0}, |
| 128 |
{0, 1.8}, {0, -1.8}, {1.8, 0}, |
| 129 |
{-1.8, 1.8}, {-1.8, -1.8}, {1.8, 1.8}, |
| 130 |
{1.8, -1.8}, {-2.4, 0}, {0, 2.4}, |
| 131 |
{0, -2.4}, {2.4, 0}, |
| 132 |
}; |
| 133 |
#define neighbors(i,j) \ |
| 134 |
((dir2check[i][0]-dir2check[j][0])*(dir2check[i][0]-dir2check[j][0]) + \ |
| 135 |
(dir2check[i][1]-dir2check[j][1])*(dir2check[i][1]-dir2check[j][1]) <= 0.73) |
| 136 |
const double peak_over = 1.5; |
| 137 |
PEAKSAMP psamp[NDIR2CHECK]; |
| 138 |
SDSpectralDF *dfp; |
| 139 |
FVECT pdir; |
| 140 |
double tomega, srchrad; |
| 141 |
double tomsum, tomsurr; |
| 142 |
COLOR vpeak, vsurr; |
| 143 |
double vypeak; |
| 144 |
int i, j, ns; |
| 145 |
SDError ec; |
| 146 |
|
| 147 |
if (ndp->pr->rod > 0) |
| 148 |
dfp = (ndp->sd->tf != NULL) ? ndp->sd->tf : ndp->sd->tb; |
| 149 |
else |
| 150 |
dfp = (ndp->sd->tb != NULL) ? ndp->sd->tb : ndp->sd->tf; |
| 151 |
|
| 152 |
if (dfp == NULL) |
| 153 |
return; /* no specular transmission */ |
| 154 |
if (bright(ndp->pr->pcol) <= FTINY) |
| 155 |
return; /* pattern is black, here */ |
| 156 |
srchrad = sqrt(dfp->minProjSA); /* else evaluate peak */ |
| 157 |
for (i = 0; i < NDIR2CHECK; i++) { |
| 158 |
SDValue sv; |
| 159 |
psamp[i].tdir[0] = -ndp->vray[0] + dir2check[i][0]*srchrad; |
| 160 |
psamp[i].tdir[1] = -ndp->vray[1] + dir2check[i][1]*srchrad; |
| 161 |
psamp[i].tdir[2] = -ndp->vray[2]; |
| 162 |
normalize(psamp[i].tdir); |
| 163 |
ec = SDevalBSDF(&sv, psamp[i].tdir, ndp->vray, ndp->sd); |
| 164 |
if (ec) |
| 165 |
goto baderror; |
| 166 |
cvt_sdcolor(psamp[i].vcol, &sv); |
| 167 |
psamp[i].vy = sv.cieY; |
| 168 |
} |
| 169 |
qsort(psamp, NDIR2CHECK, sizeof(PEAKSAMP), cmp_psamp); |
| 170 |
if (psamp[0].vy <= FTINY) |
| 171 |
return; /* zero area */ |
| 172 |
setcolor(vpeak, 0, 0, 0); |
| 173 |
setcolor(vsurr, 0, 0, 0); |
| 174 |
vypeak = tomsum = tomsurr = 0; /* combine top unique values */ |
| 175 |
ns = 0; |
| 176 |
for (i = 0; i < NDIR2CHECK; i++) { |
| 177 |
for (j = i; j--; ) /* check for duplicate sample */ |
| 178 |
if (psamp[j].vy == psamp[i].vy && neighbors(i,j)) |
| 179 |
break; |
| 180 |
if (j >= 0) |
| 181 |
continue; /* skip duplicate */ |
| 182 |
|
| 183 |
ec = SDsizeBSDF(&tomega, psamp[i].tdir, ndp->vray, |
| 184 |
SDqueryMin, ndp->sd); |
| 185 |
if (ec) |
| 186 |
goto baderror; |
| 187 |
/* not really a peak? */ |
| 188 |
if (tomega > 1.5*dfp->minProjSA || |
| 189 |
vypeak > 8.*psamp[i].vy*ns) { |
| 190 |
if (!i) return; /* abort */ |
| 191 |
scalecolor(psamp[i].vcol, tomega); |
| 192 |
addcolor(vsurr, psamp[i].vcol); |
| 193 |
tomsurr += tomega; |
| 194 |
continue; |
| 195 |
} |
| 196 |
scalecolor(psamp[i].vcol, tomega); |
| 197 |
addcolor(vpeak, psamp[i].vcol); |
| 198 |
tomsum += tomega; |
| 199 |
vypeak += psamp[i].vy; |
| 200 |
++ns; |
| 201 |
} |
| 202 |
if (vypeak*tomsurr < peak_over*bright(vsurr)*ns) |
| 203 |
return; /* peak not peaky enough */ |
| 204 |
if ((vypeak/ns - (ndp->vray[2] > 0 ? ndp->sd->tLambFront.cieY |
| 205 |
: ndp->sd->tLambBack.cieY)*(1./PI))*tomsum <= .001) |
| 206 |
return; /* < 0.1% transmission */ |
| 207 |
copycolor(ndp->cthru, vpeak); /* already scaled by omega */ |
| 208 |
multcolor(ndp->cthru, ndp->pr->pcol); /* modify by pattern */ |
| 209 |
if (tomsurr > FTINY) { /* surround contribution? */ |
| 210 |
scalecolor(vsurr, 1./tomsurr); /* this one is avg. BTDF */ |
| 211 |
copycolor(ndp->cthru_surr, vsurr); |
| 212 |
multcolor(ndp->cthru_surr, ndp->pr->pcol); |
| 213 |
} |
| 214 |
return; |
| 215 |
baderror: |
| 216 |
objerror(ndp->mp, USER, transSDError(ec)); |
| 217 |
#undef neighbors |
| 218 |
#undef NDIR2CHECK |
| 219 |
} |
| 220 |
|
| 221 |
/* Jitter ray sample according to projected solid angle and specjitter */ |
| 222 |
static void |
| 223 |
bsdf_jitter(FVECT vres, BSDFDAT *ndp, double sr_psa) |
| 224 |
{ |
| 225 |
VCOPY(vres, ndp->vray); |
| 226 |
if (specjitter < 1.) |
| 227 |
sr_psa *= specjitter; |
| 228 |
if (sr_psa <= FTINY) |
| 229 |
return; |
| 230 |
vres[0] += sr_psa*(.5 - frandom()); |
| 231 |
vres[1] += sr_psa*(.5 - frandom()); |
| 232 |
normalize(vres); |
| 233 |
} |
| 234 |
|
| 235 |
/* Get BSDF specular for direct component, returning true if OK to proceed */ |
| 236 |
static int |
| 237 |
direct_specular_OK(COLOR cval, FVECT ldir, double omega, BSDFDAT *ndp) |
| 238 |
{ |
| 239 |
int nsamp; |
| 240 |
double wtot = 0; |
| 241 |
FVECT vsrc, vsmp, vjit; |
| 242 |
double tomega, tomega2; |
| 243 |
double sf, tsr, sd[2]; |
| 244 |
COLOR csmp, cdiff; |
| 245 |
double diffY; |
| 246 |
SDValue sv; |
| 247 |
SDError ec; |
| 248 |
int i; |
| 249 |
/* in case we fail */ |
| 250 |
setcolor(cval, 0, 0, 0); |
| 251 |
/* transform source direction */ |
| 252 |
if (SDmapDir(vsrc, ndp->toloc, ldir) != SDEnone) |
| 253 |
return(0); |
| 254 |
/* will discount diffuse portion */ |
| 255 |
switch ((vsrc[2] > 0)<<1 | (ndp->vray[2] > 0)) { |
| 256 |
case 3: |
| 257 |
if (ndp->sd->rf == NULL) |
| 258 |
return(0); /* all diffuse */ |
| 259 |
sv = ndp->sd->rLambFront; |
| 260 |
break; |
| 261 |
case 0: |
| 262 |
if (ndp->sd->rb == NULL) |
| 263 |
return(0); /* all diffuse */ |
| 264 |
sv = ndp->sd->rLambBack; |
| 265 |
break; |
| 266 |
case 1: |
| 267 |
if ((ndp->sd->tf == NULL) & (ndp->sd->tb == NULL)) |
| 268 |
return(0); /* all diffuse */ |
| 269 |
sv = ndp->sd->tLambFront; |
| 270 |
break; |
| 271 |
case 2: |
| 272 |
if ((ndp->sd->tf == NULL) & (ndp->sd->tb == NULL)) |
| 273 |
return(0); /* all diffuse */ |
| 274 |
sv = ndp->sd->tLambBack; |
| 275 |
break; |
| 276 |
} |
| 277 |
if (sv.cieY > FTINY) { |
| 278 |
diffY = sv.cieY *= 1./PI; |
| 279 |
cvt_sdcolor(cdiff, &sv); |
| 280 |
} else { |
| 281 |
diffY = 0; |
| 282 |
setcolor(cdiff, 0, 0, 0); |
| 283 |
} |
| 284 |
/* need projected solid angle */ |
| 285 |
omega *= fabs(vsrc[2]); |
| 286 |
/* check indirect over-counting */ |
| 287 |
if ((vsrc[2] > 0) ^ (ndp->vray[2] > 0) && bright(ndp->cthru) > FTINY) { |
| 288 |
double dx = vsrc[0] + ndp->vray[0]; |
| 289 |
double dy = vsrc[1] + ndp->vray[1]; |
| 290 |
SDSpectralDF *dfp = (ndp->pr->rod > 0) ? |
| 291 |
((ndp->sd->tf != NULL) ? ndp->sd->tf : ndp->sd->tb) : |
| 292 |
((ndp->sd->tb != NULL) ? ndp->sd->tb : ndp->sd->tf) ; |
| 293 |
|
| 294 |
if (dx*dx + dy*dy <= (2.5*4./PI)*(omega + dfp->minProjSA + |
| 295 |
2.*sqrt(omega*dfp->minProjSA))) { |
| 296 |
if (bright(ndp->cthru_surr) <= FTINY) |
| 297 |
return(0); |
| 298 |
copycolor(cval, ndp->cthru_surr); |
| 299 |
return(1); /* return non-zero surround BTDF */ |
| 300 |
} |
| 301 |
} |
| 302 |
ec = SDsizeBSDF(&tomega, ndp->vray, vsrc, SDqueryMin, ndp->sd); |
| 303 |
if (ec) |
| 304 |
goto baderror; |
| 305 |
/* assign number of samples */ |
| 306 |
sf = specjitter * ndp->pr->rweight; |
| 307 |
if (tomega <= 0) |
| 308 |
nsamp = 1; |
| 309 |
else if (25.*tomega <= omega) |
| 310 |
nsamp = 100.*sf + .5; |
| 311 |
else |
| 312 |
nsamp = 4.*sf*omega/tomega + .5; |
| 313 |
nsamp += !nsamp; |
| 314 |
sf = sqrt(omega); /* sample our source area */ |
| 315 |
tsr = sqrt(tomega); |
| 316 |
for (i = nsamp; i--; ) { |
| 317 |
VCOPY(vsmp, vsrc); /* jitter query directions */ |
| 318 |
if (nsamp > 1) { |
| 319 |
multisamp(sd, 2, (i + frandom())/(double)nsamp); |
| 320 |
vsmp[0] += (sd[0] - .5)*sf; |
| 321 |
vsmp[1] += (sd[1] - .5)*sf; |
| 322 |
normalize(vsmp); |
| 323 |
} |
| 324 |
bsdf_jitter(vjit, ndp, tsr); |
| 325 |
/* compute BSDF */ |
| 326 |
ec = SDevalBSDF(&sv, vjit, vsmp, ndp->sd); |
| 327 |
if (ec) |
| 328 |
goto baderror; |
| 329 |
if (sv.cieY - diffY <= FTINY) |
| 330 |
continue; /* no specular part */ |
| 331 |
/* check for variable resolution */ |
| 332 |
ec = SDsizeBSDF(&tomega2, vjit, vsmp, SDqueryMin, ndp->sd); |
| 333 |
if (ec) |
| 334 |
goto baderror; |
| 335 |
if (tomega2 < .12*tomega) |
| 336 |
continue; /* not safe to include */ |
| 337 |
cvt_sdcolor(csmp, &sv); |
| 338 |
#if 0 |
| 339 |
if (sf < 2.5*tsr) { /* weight by BSDF for small sources */ |
| 340 |
scalecolor(csmp, sv.cieY); |
| 341 |
wtot += sv.cieY; |
| 342 |
} else |
| 343 |
#endif |
| 344 |
wtot += 1.; |
| 345 |
addcolor(cval, csmp); |
| 346 |
} |
| 347 |
if (wtot <= FTINY) /* no valid specular samples? */ |
| 348 |
return(0); |
| 349 |
|
| 350 |
sf = 1./wtot; /* weighted average BSDF */ |
| 351 |
scalecolor(cval, sf); |
| 352 |
/* subtract diffuse contribution */ |
| 353 |
for (i = 3*(diffY > FTINY); i--; ) |
| 354 |
if ((colval(cval,i) -= colval(cdiff,i)) < 0) |
| 355 |
colval(cval,i) = 0; |
| 356 |
return(1); |
| 357 |
baderror: |
| 358 |
objerror(ndp->mp, USER, transSDError(ec)); |
| 359 |
return(0); /* gratis return */ |
| 360 |
} |
| 361 |
|
| 362 |
/* Compute source contribution for BSDF (reflected & transmitted) */ |
| 363 |
static void |
| 364 |
dir_bsdf( |
| 365 |
COLOR cval, /* returned coefficient */ |
| 366 |
void *nnp, /* material data */ |
| 367 |
FVECT ldir, /* light source direction */ |
| 368 |
double omega /* light source size */ |
| 369 |
) |
| 370 |
{ |
| 371 |
BSDFDAT *np = (BSDFDAT *)nnp; |
| 372 |
double ldot; |
| 373 |
double dtmp; |
| 374 |
COLOR ctmp; |
| 375 |
|
| 376 |
setcolor(cval, 0, 0, 0); |
| 377 |
|
| 378 |
ldot = DOT(np->pnorm, ldir); |
| 379 |
if ((-FTINY <= ldot) & (ldot <= FTINY)) |
| 380 |
return; |
| 381 |
|
| 382 |
if (ldot > 0 && bright(np->rdiff) > FTINY) { |
| 383 |
/* |
| 384 |
* Compute diffuse reflected component |
| 385 |
*/ |
| 386 |
copycolor(ctmp, np->rdiff); |
| 387 |
dtmp = ldot * omega * (1./PI); |
| 388 |
scalecolor(ctmp, dtmp); |
| 389 |
addcolor(cval, ctmp); |
| 390 |
} |
| 391 |
if (ldot < 0 && bright(np->tdiff) > FTINY) { |
| 392 |
/* |
| 393 |
* Compute diffuse transmission |
| 394 |
*/ |
| 395 |
copycolor(ctmp, np->tdiff); |
| 396 |
dtmp = -ldot * omega * (1.0/PI); |
| 397 |
scalecolor(ctmp, dtmp); |
| 398 |
addcolor(cval, ctmp); |
| 399 |
} |
| 400 |
if (ambRayInPmap(np->pr)) |
| 401 |
return; /* specular already in photon map */ |
| 402 |
/* |
| 403 |
* Compute specular scattering coefficient using BSDF |
| 404 |
*/ |
| 405 |
if (!direct_specular_OK(ctmp, ldir, omega, np)) |
| 406 |
return; |
| 407 |
if (ldot < 0) { /* pattern for specular transmission */ |
| 408 |
multcolor(ctmp, np->pr->pcol); |
| 409 |
dtmp = -ldot * omega; |
| 410 |
} else |
| 411 |
dtmp = ldot * omega; |
| 412 |
scalecolor(ctmp, dtmp); |
| 413 |
addcolor(cval, ctmp); |
| 414 |
} |
| 415 |
|
| 416 |
/* Compute source contribution for BSDF (reflected only) */ |
| 417 |
static void |
| 418 |
dir_brdf( |
| 419 |
COLOR cval, /* returned coefficient */ |
| 420 |
void *nnp, /* material data */ |
| 421 |
FVECT ldir, /* light source direction */ |
| 422 |
double omega /* light source size */ |
| 423 |
) |
| 424 |
{ |
| 425 |
BSDFDAT *np = (BSDFDAT *)nnp; |
| 426 |
double ldot; |
| 427 |
double dtmp; |
| 428 |
COLOR ctmp, ctmp1, ctmp2; |
| 429 |
|
| 430 |
setcolor(cval, 0, 0, 0); |
| 431 |
|
| 432 |
ldot = DOT(np->pnorm, ldir); |
| 433 |
|
| 434 |
if (ldot <= FTINY) |
| 435 |
return; |
| 436 |
|
| 437 |
if (bright(np->rdiff) > FTINY) { |
| 438 |
/* |
| 439 |
* Compute diffuse reflected component |
| 440 |
*/ |
| 441 |
copycolor(ctmp, np->rdiff); |
| 442 |
dtmp = ldot * omega * (1./PI); |
| 443 |
scalecolor(ctmp, dtmp); |
| 444 |
addcolor(cval, ctmp); |
| 445 |
} |
| 446 |
if (ambRayInPmap(np->pr)) |
| 447 |
return; /* specular already in photon map */ |
| 448 |
/* |
| 449 |
* Compute specular reflection coefficient using BSDF |
| 450 |
*/ |
| 451 |
if (!direct_specular_OK(ctmp, ldir, omega, np)) |
| 452 |
return; |
| 453 |
dtmp = ldot * omega; |
| 454 |
scalecolor(ctmp, dtmp); |
| 455 |
addcolor(cval, ctmp); |
| 456 |
} |
| 457 |
|
| 458 |
/* Compute source contribution for BSDF (transmitted only) */ |
| 459 |
static void |
| 460 |
dir_btdf( |
| 461 |
COLOR cval, /* returned coefficient */ |
| 462 |
void *nnp, /* material data */ |
| 463 |
FVECT ldir, /* light source direction */ |
| 464 |
double omega /* light source size */ |
| 465 |
) |
| 466 |
{ |
| 467 |
BSDFDAT *np = (BSDFDAT *)nnp; |
| 468 |
double ldot; |
| 469 |
double dtmp; |
| 470 |
COLOR ctmp; |
| 471 |
|
| 472 |
setcolor(cval, 0, 0, 0); |
| 473 |
|
| 474 |
ldot = DOT(np->pnorm, ldir); |
| 475 |
|
| 476 |
if (ldot >= -FTINY) |
| 477 |
return; |
| 478 |
|
| 479 |
if (bright(np->tdiff) > FTINY) { |
| 480 |
/* |
| 481 |
* Compute diffuse transmission |
| 482 |
*/ |
| 483 |
copycolor(ctmp, np->tdiff); |
| 484 |
dtmp = -ldot * omega * (1.0/PI); |
| 485 |
scalecolor(ctmp, dtmp); |
| 486 |
addcolor(cval, ctmp); |
| 487 |
} |
| 488 |
if (ambRayInPmap(np->pr)) |
| 489 |
return; /* specular already in photon map */ |
| 490 |
/* |
| 491 |
* Compute specular scattering coefficient using BSDF |
| 492 |
*/ |
| 493 |
if (!direct_specular_OK(ctmp, ldir, omega, np)) |
| 494 |
return; |
| 495 |
/* full pattern on transmission */ |
| 496 |
multcolor(ctmp, np->pr->pcol); |
| 497 |
dtmp = -ldot * omega; |
| 498 |
scalecolor(ctmp, dtmp); |
| 499 |
addcolor(cval, ctmp); |
| 500 |
} |
| 501 |
|
| 502 |
/* Sample separate BSDF component */ |
| 503 |
static int |
| 504 |
sample_sdcomp(BSDFDAT *ndp, SDComponent *dcp, int xmit) |
| 505 |
{ |
| 506 |
const int hasthru = (xmit && |
| 507 |
!(ndp->pr->crtype & (SPECULAR|AMBIENT)) |
| 508 |
&& bright(ndp->cthru) > FTINY); |
| 509 |
int nstarget = 1; |
| 510 |
int nsent = 0; |
| 511 |
int n; |
| 512 |
SDError ec; |
| 513 |
SDValue bsv; |
| 514 |
double xrand; |
| 515 |
FVECT vsmp, vinc; |
| 516 |
RAY sr; |
| 517 |
/* multiple samples? */ |
| 518 |
if (specjitter > 1.5) { |
| 519 |
nstarget = specjitter*ndp->pr->rweight + .5; |
| 520 |
nstarget += !nstarget; |
| 521 |
} |
| 522 |
/* run through our samples */ |
| 523 |
for (n = 0; n < nstarget; n++) { |
| 524 |
if (nstarget == 1) { /* stratify random variable */ |
| 525 |
xrand = urand(ilhash(dimlist,ndims)+samplendx); |
| 526 |
if (specjitter < 1.) |
| 527 |
xrand = .5 + specjitter*(xrand-.5); |
| 528 |
} else { |
| 529 |
xrand = (n + frandom())/(double)nstarget; |
| 530 |
} |
| 531 |
SDerrorDetail[0] = '\0'; /* sample direction & coef. */ |
| 532 |
bsdf_jitter(vsmp, ndp, ndp->sr_vpsa[0]); |
| 533 |
VCOPY(vinc, vsmp); /* to compare after */ |
| 534 |
ec = SDsampComponent(&bsv, vsmp, xrand, dcp); |
| 535 |
if (ec) |
| 536 |
objerror(ndp->mp, USER, transSDError(ec)); |
| 537 |
if (bsv.cieY <= FTINY) /* zero component? */ |
| 538 |
break; |
| 539 |
if (hasthru) { /* check for view ray */ |
| 540 |
double dx = vinc[0] + vsmp[0]; |
| 541 |
double dy = vinc[1] + vsmp[1]; |
| 542 |
if (dx*dx + dy*dy <= ndp->sr_vpsa[0]*ndp->sr_vpsa[0]) |
| 543 |
continue; /* exclude view sample */ |
| 544 |
} |
| 545 |
/* map non-view sample->world */ |
| 546 |
if (SDmapDir(sr.rdir, ndp->fromloc, vsmp) != SDEnone) |
| 547 |
break; |
| 548 |
/* spawn a specular ray */ |
| 549 |
if (nstarget > 1) |
| 550 |
bsv.cieY /= (double)nstarget; |
| 551 |
cvt_sdcolor(sr.rcoef, &bsv); /* use sample color */ |
| 552 |
if (xmit) /* apply pattern on transmit */ |
| 553 |
multcolor(sr.rcoef, ndp->pr->pcol); |
| 554 |
if (rayorigin(&sr, SPECULAR, ndp->pr, sr.rcoef) < 0) { |
| 555 |
if (!n & (nstarget > 1)) { |
| 556 |
n = nstarget; /* avoid infinitue loop */ |
| 557 |
nstarget = nstarget*sr.rweight/minweight; |
| 558 |
if (n == nstarget) break; |
| 559 |
n = -1; /* moved target */ |
| 560 |
} |
| 561 |
continue; /* try again */ |
| 562 |
} |
| 563 |
if (xmit && ndp->thick != 0) /* need to offset origin? */ |
| 564 |
VSUM(sr.rorg, sr.rorg, ndp->pr->ron, -ndp->thick); |
| 565 |
rayvalue(&sr); /* send & evaluate sample */ |
| 566 |
multcolor(sr.rcol, sr.rcoef); |
| 567 |
addcolor(ndp->pr->rcol, sr.rcol); |
| 568 |
++nsent; |
| 569 |
} |
| 570 |
return(nsent); |
| 571 |
} |
| 572 |
|
| 573 |
/* Sample non-diffuse components of BSDF */ |
| 574 |
static int |
| 575 |
sample_sdf(BSDFDAT *ndp, int sflags) |
| 576 |
{ |
| 577 |
int hasthru = (sflags == SDsampSpT && |
| 578 |
!(ndp->pr->crtype & (SPECULAR|AMBIENT)) |
| 579 |
&& bright(ndp->cthru) > FTINY); |
| 580 |
int n, ntotal = 0; |
| 581 |
double b = 0; |
| 582 |
SDSpectralDF *dfp; |
| 583 |
COLORV *unsc; |
| 584 |
|
| 585 |
if (sflags == SDsampSpT) { |
| 586 |
unsc = ndp->tunsamp; |
| 587 |
if (ndp->pr->rod > 0) |
| 588 |
dfp = (ndp->sd->tf != NULL) ? ndp->sd->tf : ndp->sd->tb; |
| 589 |
else |
| 590 |
dfp = (ndp->sd->tb != NULL) ? ndp->sd->tb : ndp->sd->tf; |
| 591 |
} else /* sflags == SDsampSpR */ { |
| 592 |
unsc = ndp->runsamp; |
| 593 |
if (ndp->pr->rod > 0) |
| 594 |
dfp = ndp->sd->rf; |
| 595 |
else |
| 596 |
dfp = ndp->sd->rb; |
| 597 |
} |
| 598 |
setcolor(unsc, 0, 0, 0); |
| 599 |
if (dfp == NULL) /* no specular component? */ |
| 600 |
return(0); |
| 601 |
|
| 602 |
if (hasthru) { /* separate view sample? */ |
| 603 |
RAY tr; |
| 604 |
if (rayorigin(&tr, TRANS, ndp->pr, ndp->cthru) == 0) { |
| 605 |
VCOPY(tr.rdir, ndp->pr->rdir); |
| 606 |
rayvalue(&tr); |
| 607 |
multcolor(tr.rcol, tr.rcoef); |
| 608 |
addcolor(ndp->pr->rcol, tr.rcol); |
| 609 |
ndp->pr->rxt = ndp->pr->rot + raydistance(&tr); |
| 610 |
++ntotal; |
| 611 |
b = bright(ndp->cthru); |
| 612 |
} else |
| 613 |
hasthru = 0; |
| 614 |
} |
| 615 |
if (dfp->maxHemi - b <= FTINY) { /* have specular to sample? */ |
| 616 |
b = 0; |
| 617 |
} else { |
| 618 |
FVECT vjit; |
| 619 |
bsdf_jitter(vjit, ndp, ndp->sr_vpsa[1]); |
| 620 |
b = SDdirectHemi(vjit, sflags, ndp->sd) - b; |
| 621 |
if (b < 0) b = 0; |
| 622 |
} |
| 623 |
if (b <= specthresh+FTINY) { /* below sampling threshold? */ |
| 624 |
if (b > FTINY) { /* XXX no color from BSDF */ |
| 625 |
if (sflags == SDsampSpT) { |
| 626 |
copycolor(unsc, ndp->pr->pcol); |
| 627 |
scalecolor(unsc, b); |
| 628 |
} else /* no pattern on reflection */ |
| 629 |
setcolor(unsc, b, b, b); |
| 630 |
} |
| 631 |
return(ntotal); |
| 632 |
} |
| 633 |
dimlist[ndims] = (int)(size_t)ndp->mp; /* else sample specular */ |
| 634 |
ndims += 2; |
| 635 |
for (n = dfp->ncomp; n--; ) { /* loop over components */ |
| 636 |
dimlist[ndims-1] = n + 9438; |
| 637 |
ntotal += sample_sdcomp(ndp, &dfp->comp[n], sflags==SDsampSpT); |
| 638 |
} |
| 639 |
ndims -= 2; |
| 640 |
return(ntotal); |
| 641 |
} |
| 642 |
|
| 643 |
/* Color a ray that hit a BSDF material */ |
| 644 |
int |
| 645 |
m_bsdf(OBJREC *m, RAY *r) |
| 646 |
{ |
| 647 |
int hasthick = (m->otype == MAT_BSDF); |
| 648 |
int hitfront; |
| 649 |
COLOR ctmp; |
| 650 |
SDError ec; |
| 651 |
FVECT upvec, vtmp; |
| 652 |
MFUNC *mf; |
| 653 |
BSDFDAT nd; |
| 654 |
/* check arguments */ |
| 655 |
if ((m->oargs.nsargs < hasthick+5) | (m->oargs.nfargs > 9) | |
| 656 |
(m->oargs.nfargs % 3)) |
| 657 |
objerror(m, USER, "bad # arguments"); |
| 658 |
/* record surface struck */ |
| 659 |
hitfront = (r->rod > 0); |
| 660 |
/* load cal file */ |
| 661 |
mf = hasthick ? getfunc(m, 5, 0x1d, 1) |
| 662 |
: getfunc(m, 4, 0xe, 1) ; |
| 663 |
setfunc(m, r); |
| 664 |
nd.thick = 0; /* set thickness */ |
| 665 |
if (hasthick) { |
| 666 |
nd.thick = evalue(mf->ep[0]); |
| 667 |
if ((-FTINY <= nd.thick) & (nd.thick <= FTINY)) |
| 668 |
nd.thick = 0; |
| 669 |
} |
| 670 |
/* check backface visibility */ |
| 671 |
if (!hitfront & !backvis) { |
| 672 |
raytrans(r); |
| 673 |
return(1); |
| 674 |
} |
| 675 |
/* check other rays to pass */ |
| 676 |
if (nd.thick != 0 && (r->crtype & SHADOW || |
| 677 |
!(r->crtype & (SPECULAR|AMBIENT)) || |
| 678 |
(nd.thick > 0) ^ hitfront)) { |
| 679 |
raytrans(r); /* hide our proxy */ |
| 680 |
return(1); |
| 681 |
} |
| 682 |
if (hasthick && r->crtype & SHADOW) /* early shadow check #1 */ |
| 683 |
return(1); |
| 684 |
nd.mp = m; |
| 685 |
nd.pr = r; |
| 686 |
/* get BSDF data */ |
| 687 |
nd.sd = loadBSDF(m->oargs.sarg[hasthick]); |
| 688 |
/* early shadow check #2 */ |
| 689 |
if (r->crtype & SHADOW && (nd.sd->tf == NULL) & (nd.sd->tb == NULL)) { |
| 690 |
SDfreeCache(nd.sd); |
| 691 |
return(1); |
| 692 |
} |
| 693 |
/* diffuse components */ |
| 694 |
if (hitfront) { |
| 695 |
cvt_sdcolor(nd.rdiff, &nd.sd->rLambFront); |
| 696 |
if (m->oargs.nfargs >= 3) { |
| 697 |
setcolor(ctmp, m->oargs.farg[0], |
| 698 |
m->oargs.farg[1], |
| 699 |
m->oargs.farg[2]); |
| 700 |
addcolor(nd.rdiff, ctmp); |
| 701 |
} |
| 702 |
cvt_sdcolor(nd.tdiff, &nd.sd->tLambFront); |
| 703 |
} else { |
| 704 |
cvt_sdcolor(nd.rdiff, &nd.sd->rLambBack); |
| 705 |
if (m->oargs.nfargs >= 6) { |
| 706 |
setcolor(ctmp, m->oargs.farg[3], |
| 707 |
m->oargs.farg[4], |
| 708 |
m->oargs.farg[5]); |
| 709 |
addcolor(nd.rdiff, ctmp); |
| 710 |
} |
| 711 |
cvt_sdcolor(nd.tdiff, &nd.sd->tLambBack); |
| 712 |
} |
| 713 |
if (m->oargs.nfargs >= 9) { /* add diffuse transmittance? */ |
| 714 |
setcolor(ctmp, m->oargs.farg[6], |
| 715 |
m->oargs.farg[7], |
| 716 |
m->oargs.farg[8]); |
| 717 |
addcolor(nd.tdiff, ctmp); |
| 718 |
} |
| 719 |
/* get modifiers */ |
| 720 |
raytexture(r, m->omod); |
| 721 |
/* modify diffuse values */ |
| 722 |
multcolor(nd.rdiff, r->pcol); |
| 723 |
multcolor(nd.tdiff, r->pcol); |
| 724 |
/* get up vector */ |
| 725 |
upvec[0] = evalue(mf->ep[hasthick+0]); |
| 726 |
upvec[1] = evalue(mf->ep[hasthick+1]); |
| 727 |
upvec[2] = evalue(mf->ep[hasthick+2]); |
| 728 |
/* return to world coords */ |
| 729 |
if (mf->fxp != &unitxf) { |
| 730 |
multv3(upvec, upvec, mf->fxp->xfm); |
| 731 |
nd.thick *= mf->fxp->sca; |
| 732 |
} |
| 733 |
if (r->rox != NULL) { |
| 734 |
multv3(upvec, upvec, r->rox->f.xfm); |
| 735 |
nd.thick *= r->rox->f.sca; |
| 736 |
} |
| 737 |
raynormal(nd.pnorm, r); |
| 738 |
/* compute local BSDF xform */ |
| 739 |
ec = SDcompXform(nd.toloc, nd.pnorm, upvec); |
| 740 |
if (!ec) { |
| 741 |
nd.vray[0] = -r->rdir[0]; |
| 742 |
nd.vray[1] = -r->rdir[1]; |
| 743 |
nd.vray[2] = -r->rdir[2]; |
| 744 |
ec = SDmapDir(nd.vray, nd.toloc, nd.vray); |
| 745 |
} |
| 746 |
if (ec) { |
| 747 |
objerror(m, WARNING, "Illegal orientation vector"); |
| 748 |
SDfreeCache(nd.sd); |
| 749 |
return(1); |
| 750 |
} |
| 751 |
setcolor(nd.cthru, 0, 0, 0); /* consider through component */ |
| 752 |
setcolor(nd.cthru_surr, 0, 0, 0); |
| 753 |
if (m->otype == MAT_ABSDF) { |
| 754 |
compute_through(&nd); |
| 755 |
if (r->crtype & SHADOW) { |
| 756 |
RAY tr; /* attempt to pass shadow ray */ |
| 757 |
SDfreeCache(nd.sd); |
| 758 |
if (rayorigin(&tr, TRANS, r, nd.cthru) < 0) |
| 759 |
return(1); /* no through component */ |
| 760 |
VCOPY(tr.rdir, r->rdir); |
| 761 |
rayvalue(&tr); /* transmit with scaling */ |
| 762 |
multcolor(tr.rcol, tr.rcoef); |
| 763 |
copycolor(r->rcol, tr.rcol); |
| 764 |
return(1); /* we're done */ |
| 765 |
} |
| 766 |
} |
| 767 |
ec = SDinvXform(nd.fromloc, nd.toloc); |
| 768 |
if (!ec) /* determine BSDF resolution */ |
| 769 |
ec = SDsizeBSDF(nd.sr_vpsa, nd.vray, NULL, |
| 770 |
SDqueryMin+SDqueryMax, nd.sd); |
| 771 |
if (ec) |
| 772 |
objerror(m, USER, transSDError(ec)); |
| 773 |
|
| 774 |
nd.sr_vpsa[0] = sqrt(nd.sr_vpsa[0]); |
| 775 |
nd.sr_vpsa[1] = sqrt(nd.sr_vpsa[1]); |
| 776 |
if (!hitfront) { /* perturb normal towards hit */ |
| 777 |
nd.pnorm[0] = -nd.pnorm[0]; |
| 778 |
nd.pnorm[1] = -nd.pnorm[1]; |
| 779 |
nd.pnorm[2] = -nd.pnorm[2]; |
| 780 |
} |
| 781 |
/* sample reflection */ |
| 782 |
sample_sdf(&nd, SDsampSpR); |
| 783 |
/* sample transmission */ |
| 784 |
sample_sdf(&nd, SDsampSpT); |
| 785 |
/* compute indirect diffuse */ |
| 786 |
copycolor(ctmp, nd.rdiff); |
| 787 |
addcolor(ctmp, nd.runsamp); |
| 788 |
if (bright(ctmp) > FTINY) { /* ambient from reflection */ |
| 789 |
if (!hitfront) |
| 790 |
flipsurface(r); |
| 791 |
multambient(ctmp, r, nd.pnorm); |
| 792 |
addcolor(r->rcol, ctmp); |
| 793 |
if (!hitfront) |
| 794 |
flipsurface(r); |
| 795 |
} |
| 796 |
copycolor(ctmp, nd.tdiff); |
| 797 |
addcolor(ctmp, nd.tunsamp); |
| 798 |
if (bright(ctmp) > FTINY) { /* ambient from other side */ |
| 799 |
FVECT bnorm; |
| 800 |
if (hitfront) |
| 801 |
flipsurface(r); |
| 802 |
bnorm[0] = -nd.pnorm[0]; |
| 803 |
bnorm[1] = -nd.pnorm[1]; |
| 804 |
bnorm[2] = -nd.pnorm[2]; |
| 805 |
if (nd.thick != 0) { /* proxy with offset? */ |
| 806 |
VCOPY(vtmp, r->rop); |
| 807 |
VSUM(r->rop, vtmp, r->ron, nd.thick); |
| 808 |
multambient(ctmp, r, bnorm); |
| 809 |
VCOPY(r->rop, vtmp); |
| 810 |
} else |
| 811 |
multambient(ctmp, r, bnorm); |
| 812 |
addcolor(r->rcol, ctmp); |
| 813 |
if (hitfront) |
| 814 |
flipsurface(r); |
| 815 |
} |
| 816 |
/* add direct component */ |
| 817 |
if ((bright(nd.tdiff) <= FTINY) & (nd.sd->tf == NULL) & |
| 818 |
(nd.sd->tb == NULL)) { |
| 819 |
direct(r, dir_brdf, &nd); /* reflection only */ |
| 820 |
} else if (nd.thick == 0) { |
| 821 |
direct(r, dir_bsdf, &nd); /* thin surface scattering */ |
| 822 |
} else { |
| 823 |
direct(r, dir_brdf, &nd); /* reflection first */ |
| 824 |
VCOPY(vtmp, r->rop); /* offset for transmitted */ |
| 825 |
VSUM(r->rop, vtmp, r->ron, -nd.thick); |
| 826 |
direct(r, dir_btdf, &nd); /* separate transmission */ |
| 827 |
VCOPY(r->rop, vtmp); |
| 828 |
} |
| 829 |
/* clean up */ |
| 830 |
SDfreeCache(nd.sd); |
| 831 |
return(1); |
| 832 |
} |
