| 1 |
#ifndef lint |
| 2 |
static const char RCSid[] = "$Id: bsdf_t.c,v 3.5 2011/04/19 21:31:22 greg Exp $"; |
| 3 |
#endif |
| 4 |
/* |
| 5 |
* bsdf_t.c |
| 6 |
* |
| 7 |
* Definitions for variable-resolution BSDF trees |
| 8 |
* |
| 9 |
* Created by Greg Ward on 2/2/11. |
| 10 |
* |
| 11 |
*/ |
| 12 |
|
| 13 |
#include "rtio.h" |
| 14 |
#include <stdlib.h> |
| 15 |
#include <math.h> |
| 16 |
#include <ctype.h> |
| 17 |
#include "ezxml.h" |
| 18 |
#include "bsdf.h" |
| 19 |
#include "bsdf_t.h" |
| 20 |
#include "hilbert.h" |
| 21 |
|
| 22 |
/* Callback function type for SDtraverseTre() */ |
| 23 |
typedef int SDtreCallback(float val, const double *cmin, |
| 24 |
double csiz, void *cptr); |
| 25 |
|
| 26 |
/* reference width maximum (1.0) */ |
| 27 |
static const unsigned iwmax = (1<<(sizeof(unsigned)*4))-1; |
| 28 |
|
| 29 |
/* Struct used for our distribution-building callback */ |
| 30 |
typedef struct { |
| 31 |
int wmin; /* minimum square size so far */ |
| 32 |
int wmax; /* maximum square size */ |
| 33 |
int nic; /* number of input coordinates */ |
| 34 |
int alen; /* current array length */ |
| 35 |
int nall; /* number of allocated entries */ |
| 36 |
struct outdir_s { |
| 37 |
unsigned hent; /* entering Hilbert index */ |
| 38 |
int wid; /* this square size */ |
| 39 |
float bsdf; /* BSDF for this square */ |
| 40 |
} *darr; /* output direction array */ |
| 41 |
} SDdistScaffold; |
| 42 |
|
| 43 |
/* Allocate a new scattering distribution node */ |
| 44 |
static SDNode * |
| 45 |
SDnewNode(int nd, int lg) |
| 46 |
{ |
| 47 |
SDNode *st; |
| 48 |
|
| 49 |
if (nd <= 0) { |
| 50 |
strcpy(SDerrorDetail, "Zero dimension BSDF node request"); |
| 51 |
return NULL; |
| 52 |
} |
| 53 |
if (nd > SD_MAXDIM) { |
| 54 |
sprintf(SDerrorDetail, "Illegal BSDF dimension (%d > %d)", |
| 55 |
nd, SD_MAXDIM); |
| 56 |
return NULL; |
| 57 |
} |
| 58 |
if (lg < 0) { |
| 59 |
st = (SDNode *)malloc(sizeof(SDNode) + |
| 60 |
((1<<nd) - 1)*sizeof(st->u.t[0])); |
| 61 |
if (st != NULL) |
| 62 |
memset(st->u.t, 0, sizeof(st->u.t[0])<<nd); |
| 63 |
} else |
| 64 |
st = (SDNode *)malloc(sizeof(SDNode) + |
| 65 |
((1 << nd*lg) - 1)*sizeof(st->u.v[0])); |
| 66 |
|
| 67 |
if (st == NULL) { |
| 68 |
if (lg < 0) |
| 69 |
sprintf(SDerrorDetail, |
| 70 |
"Cannot allocate %d branch BSDF tree", 1<<nd); |
| 71 |
else |
| 72 |
sprintf(SDerrorDetail, |
| 73 |
"Cannot allocate %d BSDF leaves", 1 << nd*lg); |
| 74 |
return NULL; |
| 75 |
} |
| 76 |
st->ndim = nd; |
| 77 |
st->log2GR = lg; |
| 78 |
return st; |
| 79 |
} |
| 80 |
|
| 81 |
/* Free an SD tree */ |
| 82 |
static void |
| 83 |
SDfreeTre(SDNode *st) |
| 84 |
{ |
| 85 |
int i; |
| 86 |
|
| 87 |
if (st == NULL) |
| 88 |
return; |
| 89 |
for (i = (st->log2GR < 0) << st->ndim; i--; ) |
| 90 |
SDfreeTre(st->u.t[i]); |
| 91 |
free((void *)st); |
| 92 |
} |
| 93 |
|
| 94 |
/* Free a variable-resolution BSDF */ |
| 95 |
static void |
| 96 |
SDFreeBTre(void *p) |
| 97 |
{ |
| 98 |
SDTre *sdt = (SDTre *)p; |
| 99 |
|
| 100 |
if (sdt == NULL) |
| 101 |
return; |
| 102 |
SDfreeTre(sdt->st); |
| 103 |
free(sdt); |
| 104 |
} |
| 105 |
|
| 106 |
/* Add up N-dimensional hypercube array values over the given box */ |
| 107 |
static double |
| 108 |
SDiterSum(const float *va, int nd, int siz, const int *imin, const int *imax) |
| 109 |
{ |
| 110 |
double sum = .0; |
| 111 |
unsigned skipsiz = 1; |
| 112 |
int i; |
| 113 |
|
| 114 |
for (i = nd; --i > 0; ) |
| 115 |
skipsiz *= siz; |
| 116 |
if (skipsiz == 1) |
| 117 |
for (i = *imin; i < *imax; i++) |
| 118 |
sum += va[i]; |
| 119 |
else |
| 120 |
for (i = *imin; i < *imax; i++) |
| 121 |
sum += SDiterSum(va + i*skipsiz, |
| 122 |
nd-1, siz, imin+1, imax+1); |
| 123 |
return sum; |
| 124 |
} |
| 125 |
|
| 126 |
/* Average BSDF leaves over an orthotope defined by the unit hypercube */ |
| 127 |
static double |
| 128 |
SDavgTreBox(const SDNode *st, const double *bmin, const double *bmax) |
| 129 |
{ |
| 130 |
int imin[SD_MAXDIM], imax[SD_MAXDIM]; |
| 131 |
unsigned n; |
| 132 |
int i; |
| 133 |
|
| 134 |
if (!st) |
| 135 |
return .0; |
| 136 |
/* check box limits */ |
| 137 |
for (i = st->ndim; i--; ) { |
| 138 |
if (bmin[i] >= 1.) |
| 139 |
return .0; |
| 140 |
if (bmax[i] <= .0) |
| 141 |
return .0; |
| 142 |
if (bmin[i] >= bmax[i]) |
| 143 |
return .0; |
| 144 |
} |
| 145 |
if (st->log2GR < 0) { /* iterate on subtree */ |
| 146 |
double sum = .0, wsum = 1e-20; |
| 147 |
double sbmin[SD_MAXDIM], sbmax[SD_MAXDIM], w; |
| 148 |
|
| 149 |
for (n = 1 << st->ndim; n--; ) { |
| 150 |
w = 1.; |
| 151 |
for (i = st->ndim; i--; ) { |
| 152 |
sbmin[i] = 2.*bmin[i]; |
| 153 |
sbmax[i] = 2.*bmax[i]; |
| 154 |
if (n & 1<<i) { |
| 155 |
sbmin[i] -= 1.; |
| 156 |
sbmax[i] -= 1.; |
| 157 |
} |
| 158 |
if (sbmin[i] < .0) sbmin[i] = .0; |
| 159 |
if (sbmax[i] > 1.) sbmax[i] = 1.; |
| 160 |
w *= sbmax[i] - sbmin[i]; |
| 161 |
} |
| 162 |
if (w > 1e-10) { |
| 163 |
sum += w * SDavgTreBox(st->u.t[n], sbmin, sbmax); |
| 164 |
wsum += w; |
| 165 |
} |
| 166 |
} |
| 167 |
return sum / wsum; |
| 168 |
} |
| 169 |
n = 1; /* iterate over leaves */ |
| 170 |
for (i = st->ndim; i--; ) { |
| 171 |
imin[i] = (bmin[i] <= .0) ? 0 |
| 172 |
: (int)((1 << st->log2GR)*bmin[i]); |
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imax[i] = (bmax[i] >= 1.) ? (1 << st->log2GR) |
| 174 |
: (int)((1 << st->log2GR)*bmax[i] + .999999); |
| 175 |
n *= imax[i] - imin[i]; |
| 176 |
} |
| 177 |
if (!n) |
| 178 |
return .0; |
| 179 |
|
| 180 |
return SDiterSum(st->u.v, st->ndim, 1 << st->log2GR, imin, imax) / |
| 181 |
(double)n; |
| 182 |
} |
| 183 |
|
| 184 |
/* Recursive call for SDtraverseTre() */ |
| 185 |
static int |
| 186 |
SDdotravTre(const SDNode *st, const double *pos, int cmask, |
| 187 |
SDtreCallback *cf, void *cptr, |
| 188 |
const double *cmin, double csiz) |
| 189 |
{ |
| 190 |
int rv, rval = 0; |
| 191 |
double bmin[SD_MAXDIM]; |
| 192 |
int i, n; |
| 193 |
/* in branches? */ |
| 194 |
if (st->log2GR < 0) { |
| 195 |
unsigned skipmask = 0; |
| 196 |
|
| 197 |
csiz *= .5; |
| 198 |
for (i = st->ndim; i--; ) |
| 199 |
if (1<<i & cmask) |
| 200 |
if (pos[i] < cmin[i] + csiz) |
| 201 |
for (n = 1 << st->ndim; n--; ) |
| 202 |
if (n & 1<<i) |
| 203 |
skipmask |= 1<<n; |
| 204 |
else |
| 205 |
for (n = 1 << st->ndim; n--; ) |
| 206 |
if (!(n & 1<<i)) |
| 207 |
skipmask |= 1<<n; |
| 208 |
for (n = 1 << st->ndim; n--; ) { |
| 209 |
if (1<<n & skipmask) |
| 210 |
continue; |
| 211 |
for (i = st->ndim; i--; ) |
| 212 |
if (1<<i & n) |
| 213 |
bmin[i] = cmin[i] + csiz; |
| 214 |
else |
| 215 |
bmin[i] = cmin[i]; |
| 216 |
|
| 217 |
rval += rv = SDdotravTre(st->u.t[n], pos, cmask, |
| 218 |
cf, cptr, bmin, csiz); |
| 219 |
if (rv < 0) |
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return rv; |
| 221 |
} |
| 222 |
} else { /* else traverse leaves */ |
| 223 |
int clim[SD_MAXDIM][2]; |
| 224 |
int cpos[SD_MAXDIM]; |
| 225 |
|
| 226 |
if (st->log2GR == 0) /* short cut */ |
| 227 |
return (*cf)(st->u.v[0], cmin, csiz, cptr); |
| 228 |
|
| 229 |
csiz /= (double)(1 << st->log2GR); |
| 230 |
/* assign coord. ranges */ |
| 231 |
for (i = st->ndim; i--; ) |
| 232 |
if (1<<i & cmask) { |
| 233 |
clim[i][0] = (pos[i] - cmin[i])/csiz; |
| 234 |
/* check overflow from f.p. error */ |
| 235 |
clim[i][0] -= clim[i][0] >> st->log2GR; |
| 236 |
clim[i][1] = clim[i][0] + 1; |
| 237 |
} else { |
| 238 |
clim[i][0] = 0; |
| 239 |
clim[i][1] = 1 << st->log2GR; |
| 240 |
} |
| 241 |
/* fill in unused dimensions */ |
| 242 |
for (i = SD_MAXDIM; i-- > st->ndim; ) { |
| 243 |
clim[i][0] = 0; clim[i][1] = 1; |
| 244 |
} |
| 245 |
#if (SD_MAXDIM == 4) |
| 246 |
bmin[0] = cmin[0] + csiz*clim[0][0]; |
| 247 |
for (cpos[0] = clim[0][0]; cpos[0] < clim[0][1]; cpos[0]++) { |
| 248 |
bmin[1] = cmin[1] + csiz*clim[1][0]; |
| 249 |
for (cpos[1] = clim[1][0]; cpos[1] < clim[1][1]; cpos[1]++) { |
| 250 |
bmin[2] = cmin[2] + csiz*clim[2][0]; |
| 251 |
for (cpos[2] = clim[2][0]; cpos[2] < clim[2][1]; cpos[2]++) { |
| 252 |
bmin[3] = cmin[3] + csiz*(cpos[3] = clim[3][0]); |
| 253 |
n = cpos[0]; |
| 254 |
for (i = 1; i < st->ndim; i++) |
| 255 |
n = (n << st->log2GR) + cpos[i]; |
| 256 |
for ( ; cpos[3] < clim[3][1]; cpos[3]++) { |
| 257 |
rval += rv = (*cf)(st->u.v[n++], bmin, csiz, cptr); |
| 258 |
if (rv < 0) |
| 259 |
return rv; |
| 260 |
bmin[3] += csiz; |
| 261 |
} |
| 262 |
bmin[2] += csiz; |
| 263 |
} |
| 264 |
bmin[1] += csiz; |
| 265 |
} |
| 266 |
bmin[0] += csiz; |
| 267 |
} |
| 268 |
#else |
| 269 |
_!_ "broken code segment!" |
| 270 |
#endif |
| 271 |
} |
| 272 |
return rval; |
| 273 |
} |
| 274 |
|
| 275 |
/* Traverse a tree, visiting nodes in a slice that fits partial position */ |
| 276 |
static int |
| 277 |
SDtraverseTre(const SDNode *st, const double *pos, int cmask, |
| 278 |
SDtreCallback *cf, void *cptr) |
| 279 |
{ |
| 280 |
static double czero[SD_MAXDIM]; |
| 281 |
int i; |
| 282 |
/* check arguments */ |
| 283 |
if ((st == NULL) | (cf == NULL)) |
| 284 |
return -1; |
| 285 |
for (i = st->ndim; i--; ) |
| 286 |
if (1<<i & cmask && (pos[i] < 0) | (pos[i] >= 1.)) |
| 287 |
return -1; |
| 288 |
|
| 289 |
return SDdotravTre(st, pos, cmask, cf, cptr, czero, 1.); |
| 290 |
} |
| 291 |
|
| 292 |
/* Look up tree value at the given grid position */ |
| 293 |
static float |
| 294 |
SDlookupTre(const SDNode *st, const double *pos, double *hcube) |
| 295 |
{ |
| 296 |
double spos[SD_MAXDIM]; |
| 297 |
int i, n, t; |
| 298 |
/* initialize voxel return */ |
| 299 |
if (hcube) { |
| 300 |
hcube[i = st->ndim] = 1.; |
| 301 |
while (i--) |
| 302 |
hcube[i] = .0; |
| 303 |
} |
| 304 |
/* climb the tree */ |
| 305 |
while (st->log2GR < 0) { |
| 306 |
n = 0; /* move to appropriate branch */ |
| 307 |
if (hcube) hcube[st->ndim] *= .5; |
| 308 |
for (i = st->ndim; i--; ) { |
| 309 |
spos[i] = 2.*pos[i]; |
| 310 |
t = (spos[i] >= 1.); |
| 311 |
n |= t<<i; |
| 312 |
spos[i] -= (double)t; |
| 313 |
if (hcube) hcube[i] += (double)t * hcube[st->ndim]; |
| 314 |
} |
| 315 |
st = st->u.t[n]; /* avoids tail recursion */ |
| 316 |
pos = spos; |
| 317 |
} |
| 318 |
if (st->log2GR == 0) /* short cut */ |
| 319 |
return st->u.v[0]; |
| 320 |
n = t = 0; /* find grid array index */ |
| 321 |
for (i = st->ndim; i--; ) { |
| 322 |
n += (int)((1<<st->log2GR)*pos[i]) << t; |
| 323 |
t += st->log2GR; |
| 324 |
} |
| 325 |
if (hcube) { /* compute final hypercube */ |
| 326 |
hcube[st->ndim] /= (double)(1<<st->log2GR); |
| 327 |
for (i = st->ndim; i--; ) |
| 328 |
hcube[i] += floor((1<<st->log2GR)*pos[i])*hcube[st->ndim]; |
| 329 |
} |
| 330 |
return st->u.v[n]; /* no interpolation */ |
| 331 |
} |
| 332 |
|
| 333 |
/* Query BSDF value and sample hypercube for the given vectors */ |
| 334 |
static float |
| 335 |
SDqueryTre(const SDTre *sdt, const FVECT outVec, const FVECT inVec, double *hc) |
| 336 |
{ |
| 337 |
static const FVECT zvec = {.0, .0, 1.}; |
| 338 |
FVECT rOutVec; |
| 339 |
double gridPos[4]; |
| 340 |
/* check transmission */ |
| 341 |
if (!sdt->isxmit ^ outVec[2] > 0 ^ inVec[2] > 0) |
| 342 |
return -1.; |
| 343 |
/* convert vector coordinates */ |
| 344 |
if (sdt->st->ndim == 3) { |
| 345 |
spinvector(rOutVec, outVec, zvec, -atan2(inVec[1],inVec[0])); |
| 346 |
gridPos[0] = .5 - .5*sqrt(inVec[0]*inVec[0] + inVec[1]*inVec[1]); |
| 347 |
SDdisk2square(gridPos+1, rOutVec[0], rOutVec[1]); |
| 348 |
} else if (sdt->st->ndim == 4) { |
| 349 |
SDdisk2square(gridPos, -inVec[0], -inVec[1]); |
| 350 |
SDdisk2square(gridPos+2, outVec[0], outVec[1]); |
| 351 |
} else |
| 352 |
return -1.; /* should be internal error */ |
| 353 |
|
| 354 |
return SDlookupTre(sdt->st, gridPos, hc); |
| 355 |
} |
| 356 |
|
| 357 |
/* Compute non-diffuse component for variable-resolution BSDF */ |
| 358 |
static int |
| 359 |
SDgetTreBSDF(float coef[SDmaxCh], const FVECT outVec, |
| 360 |
const FVECT inVec, SDComponent *sdc) |
| 361 |
{ |
| 362 |
/* check arguments */ |
| 363 |
if ((coef == NULL) | (outVec == NULL) | (inVec == NULL) | (sdc == NULL) |
| 364 |
|| sdc->dist == NULL) |
| 365 |
return 0; |
| 366 |
/* get nearest BSDF value */ |
| 367 |
coef[0] = SDqueryTre((SDTre *)sdc->dist, outVec, inVec, NULL); |
| 368 |
return (coef[0] >= 0); /* monochromatic for now */ |
| 369 |
} |
| 370 |
|
| 371 |
/* Callback to build cumulative distribution using SDtraverseTre() */ |
| 372 |
static int |
| 373 |
build_scaffold(float val, const double *cmin, double csiz, void *cptr) |
| 374 |
{ |
| 375 |
SDdistScaffold *sp = (SDdistScaffold *)cptr; |
| 376 |
int wid = csiz*(double)iwmax + .5; |
| 377 |
bitmask_t bmin[2], bmax[2]; |
| 378 |
|
| 379 |
cmin += sp->nic; /* skip to output coords */ |
| 380 |
if (wid < sp->wmin) /* new minimum width? */ |
| 381 |
sp->wmin = wid; |
| 382 |
if (wid > sp->wmax) /* new maximum? */ |
| 383 |
sp->wmax = wid; |
| 384 |
if (sp->alen >= sp->nall) { /* need more space? */ |
| 385 |
struct outdir_s *ndarr; |
| 386 |
sp->nall += 8192; |
| 387 |
ndarr = (struct outdir_s *)realloc(sp->darr, |
| 388 |
sizeof(struct outdir_s)*sp->nall); |
| 389 |
if (ndarr == NULL) |
| 390 |
return -1; /* abort build */ |
| 391 |
sp->darr = ndarr; |
| 392 |
} |
| 393 |
/* find Hilbert entry index */ |
| 394 |
bmin[0] = cmin[0]*(double)iwmax + .5; |
| 395 |
bmin[1] = cmin[1]*(double)iwmax + .5; |
| 396 |
bmax[0] = bmin[0] + wid; |
| 397 |
bmax[1] = bmin[1] + wid; |
| 398 |
hilbert_box_vtx(2, sizeof(bitmask_t), sizeof(unsigned)*4, |
| 399 |
1, bmin, bmax); |
| 400 |
sp->darr[sp->alen].hent = hilbert_c2i(2, sizeof(unsigned)*4, bmin); |
| 401 |
sp->darr[sp->alen].wid = wid; |
| 402 |
sp->darr[sp->alen].bsdf = val; |
| 403 |
sp->alen++; /* on to the next entry */ |
| 404 |
return 0; |
| 405 |
} |
| 406 |
|
| 407 |
/* Scaffold comparison function for qsort -- ascending Hilbert index */ |
| 408 |
static int |
| 409 |
sscmp(const void *p1, const void *p2) |
| 410 |
{ |
| 411 |
return (int)((*(const struct outdir_s *)p1).hent - |
| 412 |
(*(const struct outdir_s *)p2).hent); |
| 413 |
} |
| 414 |
|
| 415 |
/* Create a new cumulative distribution for the given input direction */ |
| 416 |
static SDTreCDst * |
| 417 |
make_cdist(const SDTre *sdt, const double *pos) |
| 418 |
{ |
| 419 |
const unsigned cumlmax = ~0; |
| 420 |
SDdistScaffold myScaffold; |
| 421 |
SDTreCDst *cd; |
| 422 |
struct outdir_s *sp; |
| 423 |
double scale, cursum; |
| 424 |
int i; |
| 425 |
/* initialize scaffold */ |
| 426 |
myScaffold.wmin = iwmax; |
| 427 |
myScaffold.wmax = 0; |
| 428 |
myScaffold.nic = sdt->st->ndim - 2; |
| 429 |
myScaffold.alen = 0; |
| 430 |
myScaffold.nall = 8192; |
| 431 |
myScaffold.darr = (struct outdir_s *)malloc(sizeof(struct outdir_s) * |
| 432 |
myScaffold.nall); |
| 433 |
if (myScaffold.darr == NULL) |
| 434 |
return NULL; |
| 435 |
/* grow the distribution */ |
| 436 |
if (SDtraverseTre(sdt->st, pos, (1<<myScaffold.nic)-1, |
| 437 |
&build_scaffold, &myScaffold) < 0) { |
| 438 |
free(myScaffold.darr); |
| 439 |
return NULL; |
| 440 |
} |
| 441 |
/* allocate result holder */ |
| 442 |
cd = (SDTreCDst *)malloc(sizeof(SDTreCDst) + |
| 443 |
sizeof(cd->carr[0])*myScaffold.alen); |
| 444 |
if (cd == NULL) { |
| 445 |
free(myScaffold.darr); |
| 446 |
return NULL; |
| 447 |
} |
| 448 |
/* sort the distribution */ |
| 449 |
qsort(myScaffold.darr, cd->calen = myScaffold.alen, |
| 450 |
sizeof(struct outdir_s), &sscmp); |
| 451 |
|
| 452 |
/* record input range */ |
| 453 |
scale = (double)myScaffold.wmin / iwmax; |
| 454 |
for (i = myScaffold.nic; i--; ) { |
| 455 |
cd->clim[i][0] = floor(pos[i]/scale + .5) * scale; |
| 456 |
cd->clim[i][1] = cd->clim[i][0] + scale; |
| 457 |
} |
| 458 |
cd->max_psa = myScaffold.wmax / (double)iwmax; |
| 459 |
cd->max_psa *= cd->max_psa * M_PI; |
| 460 |
cd->isxmit = sdt->isxmit; |
| 461 |
cd->cTotal = 1e-20; /* compute directional total */ |
| 462 |
sp = myScaffold.darr; |
| 463 |
for (i = myScaffold.alen; i--; sp++) |
| 464 |
cd->cTotal += sp->bsdf * (double)sp->wid * sp->wid; |
| 465 |
cursum = .0; /* go back and get cumulative values */ |
| 466 |
scale = (double)cumlmax / cd->cTotal; |
| 467 |
sp = myScaffold.darr; |
| 468 |
for (i = 0; i < cd->calen; i++, sp++) { |
| 469 |
cd->carr[i].cuml = scale*cursum + .5; |
| 470 |
cursum += sp->bsdf * (double)sp->wid * sp->wid; |
| 471 |
} |
| 472 |
cd->carr[i].hndx = ~0; /* make final entry */ |
| 473 |
cd->carr[i].cuml = cumlmax; |
| 474 |
cd->cTotal *= M_PI/(double)iwmax/iwmax; |
| 475 |
/* all done, clean up and return */ |
| 476 |
free(myScaffold.darr); |
| 477 |
return cd; |
| 478 |
} |
| 479 |
|
| 480 |
/* Find or allocate a cumulative distribution for the given incoming vector */ |
| 481 |
const SDCDst * |
| 482 |
SDgetTreCDist(const FVECT inVec, SDComponent *sdc) |
| 483 |
{ |
| 484 |
const SDTre *sdt; |
| 485 |
double inCoord[2]; |
| 486 |
int vflags; |
| 487 |
int i; |
| 488 |
SDTreCDst *cd, *cdlast; |
| 489 |
/* check arguments */ |
| 490 |
if ((inVec == NULL) | (sdc == NULL) || |
| 491 |
(sdt = (SDTre *)sdc->dist) == NULL) |
| 492 |
return NULL; |
| 493 |
if (sdt->st->ndim == 3) /* isotropic BSDF? */ |
| 494 |
inCoord[0] = .5 - .5*sqrt(inVec[0]*inVec[0] + inVec[1]*inVec[1]); |
| 495 |
else if (sdt->st->ndim == 4) |
| 496 |
SDdisk2square(inCoord, -inVec[0], -inVec[1]); |
| 497 |
else |
| 498 |
return NULL; /* should be internal error */ |
| 499 |
cdlast = NULL; /* check for direction in cache list */ |
| 500 |
for (cd = (SDTreCDst *)sdc->cdList; cd != NULL; |
| 501 |
cdlast = cd, cd = (SDTreCDst *)cd->next) { |
| 502 |
for (i = sdt->st->ndim - 2; i--; ) |
| 503 |
if ((cd->clim[i][0] > inCoord[i]) | |
| 504 |
(inCoord[i] >= cd->clim[i][1])) |
| 505 |
break; |
| 506 |
if (i < 0) |
| 507 |
break; /* means we have a match */ |
| 508 |
} |
| 509 |
if (cd == NULL) /* need to create new entry? */ |
| 510 |
cdlast = cd = make_cdist(sdt, inCoord); |
| 511 |
if (cdlast != NULL) { /* move entry to head of cache list */ |
| 512 |
cdlast->next = cd->next; |
| 513 |
cd->next = sdc->cdList; |
| 514 |
sdc->cdList = (SDCDst *)cd; |
| 515 |
} |
| 516 |
return (SDCDst *)cd; /* ready to go */ |
| 517 |
} |
| 518 |
|
| 519 |
/* Query solid angle for vector(s) */ |
| 520 |
static SDError |
| 521 |
SDqueryTreProjSA(double *psa, const FVECT v1, const RREAL *v2, |
| 522 |
int qflags, SDComponent *sdc) |
| 523 |
{ |
| 524 |
double myPSA[2]; |
| 525 |
/* check arguments */ |
| 526 |
if ((psa == NULL) | (v1 == NULL) | (sdc == NULL) || |
| 527 |
sdc->dist == NULL) |
| 528 |
return SDEargument; |
| 529 |
/* get projected solid angle(s) */ |
| 530 |
if (v2 != NULL) { |
| 531 |
const SDTre *sdt = (SDTre *)sdc->dist; |
| 532 |
double hcube[SD_MAXDIM]; |
| 533 |
if (SDqueryTre(sdt, v1, v2, hcube) < 0) { |
| 534 |
if (qflags == SDqueryVal) |
| 535 |
*psa = M_PI; |
| 536 |
return SDEnone; |
| 537 |
} |
| 538 |
myPSA[0] = hcube[sdt->st->ndim]; |
| 539 |
myPSA[1] = myPSA[0] *= myPSA[0] * M_PI; |
| 540 |
} else { |
| 541 |
const SDTreCDst *cd = (const SDTreCDst *)SDgetTreCDist(v1, sdc); |
| 542 |
if (cd == NULL) |
| 543 |
return SDEmemory; |
| 544 |
myPSA[0] = M_PI * (cd->clim[0][1] - cd->clim[0][0]) * |
| 545 |
(cd->clim[1][1] - cd->clim[1][0]); |
| 546 |
myPSA[1] = cd->max_psa; |
| 547 |
} |
| 548 |
switch (qflags) { /* record based on flag settings */ |
| 549 |
case SDqueryVal: |
| 550 |
*psa = myPSA[0]; |
| 551 |
break; |
| 552 |
case SDqueryMax: |
| 553 |
if (myPSA[1] > *psa) |
| 554 |
*psa = myPSA[1]; |
| 555 |
break; |
| 556 |
case SDqueryMin+SDqueryMax: |
| 557 |
if (myPSA[1] > psa[1]) |
| 558 |
psa[1] = myPSA[1]; |
| 559 |
/* fall through */ |
| 560 |
case SDqueryMin: |
| 561 |
if (myPSA[0] < psa[0]) |
| 562 |
psa[0] = myPSA[0]; |
| 563 |
break; |
| 564 |
} |
| 565 |
return SDEnone; |
| 566 |
} |
| 567 |
|
| 568 |
/* Sample cumulative distribution */ |
| 569 |
static SDError |
| 570 |
SDsampTreCDist(FVECT ioVec, double randX, const SDCDst *cdp) |
| 571 |
{ |
| 572 |
const unsigned nBitsC = 4*sizeof(bitmask_t); |
| 573 |
const unsigned nExtraBits = 8*(sizeof(bitmask_t)-sizeof(unsigned)); |
| 574 |
const unsigned maxval = ~0; |
| 575 |
const SDTreCDst *cd = (const SDTreCDst *)cdp; |
| 576 |
const unsigned target = randX*maxval; |
| 577 |
bitmask_t hndx, hcoord[2]; |
| 578 |
double gpos[3]; |
| 579 |
int i, iupper, ilower; |
| 580 |
/* check arguments */ |
| 581 |
if ((ioVec == NULL) | (cd == NULL)) |
| 582 |
return SDEargument; |
| 583 |
/* binary search to find position */ |
| 584 |
ilower = 0; iupper = cd->calen; |
| 585 |
while ((i = (iupper + ilower) >> 1) != ilower) |
| 586 |
if ((long)target >= (long)cd->carr[i].cuml) |
| 587 |
ilower = i; |
| 588 |
else |
| 589 |
iupper = i; |
| 590 |
/* localize random position */ |
| 591 |
randX = (randX*maxval - cd->carr[ilower].cuml) / |
| 592 |
(double)(cd->carr[iupper].cuml - cd->carr[ilower].cuml); |
| 593 |
/* index in longer Hilbert curve */ |
| 594 |
hndx = (randX*cd->carr[iupper].hndx + (1.-randX)*cd->carr[ilower].hndx) |
| 595 |
* (double)((bitmask_t)1 << nExtraBits); |
| 596 |
/* convert Hilbert index to vector */ |
| 597 |
hilbert_i2c(2, nBitsC, hndx, hcoord); |
| 598 |
for (i = 2; i--; ) |
| 599 |
gpos[i] = ((double)hcoord[i] + rand()*(1./(RAND_MAX+.5))) / |
| 600 |
(double)((bitmask_t)1 << nBitsC); |
| 601 |
SDsquare2disk(gpos, gpos[0], gpos[1]); |
| 602 |
gpos[2] = 1. - gpos[0]*gpos[0] - gpos[1]*gpos[1]; |
| 603 |
if (gpos[2] > 0) /* paranoia, I hope */ |
| 604 |
gpos[2] = sqrt(gpos[2]); |
| 605 |
if (ioVec[2] > 0 ^ !cd->isxmit) |
| 606 |
gpos[2] = -gpos[2]; |
| 607 |
VCOPY(ioVec, gpos); |
| 608 |
return SDEnone; |
| 609 |
} |
| 610 |
|
| 611 |
/* Load a variable-resolution BSDF tree from an open XML file */ |
| 612 |
SDError |
| 613 |
SDloadTre(SDData *sd, ezxml_t wtl) |
| 614 |
{ |
| 615 |
return SDEsupport; |
| 616 |
} |
| 617 |
|
| 618 |
/* Variable resolution BSDF methods */ |
| 619 |
SDFunc SDhandleTre = { |
| 620 |
&SDgetTreBSDF, |
| 621 |
&SDqueryTreProjSA, |
| 622 |
&SDgetTreCDist, |
| 623 |
&SDsampTreCDist, |
| 624 |
&SDFreeBTre, |
| 625 |
}; |
