| 1 |
#ifndef lint |
| 2 |
static const char RCSid[] = "$Id: bsdf.c,v 2.1 2009/06/12 17:37:37 greg Exp $"; |
| 3 |
#endif |
| 4 |
/* |
| 5 |
* Routines for handling BSDF data |
| 6 |
*/ |
| 7 |
|
| 8 |
#include "standard.h" |
| 9 |
#include "bsdf.h" |
| 10 |
#include "paths.h" |
| 11 |
#include "ezxml.h" |
| 12 |
#include <ctype.h> |
| 13 |
|
| 14 |
#define MAXLATS 46 /* maximum number of latitudes */ |
| 15 |
|
| 16 |
/* BSDF angle specification */ |
| 17 |
typedef struct { |
| 18 |
char name[64]; /* basis name */ |
| 19 |
int nangles; /* total number of directions */ |
| 20 |
struct { |
| 21 |
float tmin; /* starting theta */ |
| 22 |
short nphis; /* number of phis (0 term) */ |
| 23 |
} lat[MAXLATS+1]; /* latitudes */ |
| 24 |
} ANGLE_BASIS; |
| 25 |
|
| 26 |
#define MAXABASES 3 /* limit on defined bases */ |
| 27 |
|
| 28 |
static ANGLE_BASIS abase_list[MAXABASES] = { |
| 29 |
{ |
| 30 |
"LBNL/Klems Full", 145, |
| 31 |
{ {-5., 1}, |
| 32 |
{5., 8}, |
| 33 |
{15., 16}, |
| 34 |
{25., 20}, |
| 35 |
{35., 24}, |
| 36 |
{45., 24}, |
| 37 |
{55., 24}, |
| 38 |
{65., 16}, |
| 39 |
{75., 12}, |
| 40 |
{90., 0} } |
| 41 |
}, { |
| 42 |
"LBNL/Klems Half", 73, |
| 43 |
{ {-6.5, 1}, |
| 44 |
{6.5, 8}, |
| 45 |
{19.5, 12}, |
| 46 |
{32.5, 16}, |
| 47 |
{46.5, 20}, |
| 48 |
{61.5, 12}, |
| 49 |
{76.5, 4}, |
| 50 |
{90., 0} } |
| 51 |
}, { |
| 52 |
"LBNL/Klems Quarter", 41, |
| 53 |
{ {-9., 1}, |
| 54 |
{9., 8}, |
| 55 |
{27., 12}, |
| 56 |
{46., 12}, |
| 57 |
{66., 8}, |
| 58 |
{90., 0} } |
| 59 |
} |
| 60 |
}; |
| 61 |
|
| 62 |
static int nabases = 3; /* current number of defined bases */ |
| 63 |
|
| 64 |
|
| 65 |
static int |
| 66 |
ab_getvec( /* get vector for this angle basis index */ |
| 67 |
FVECT v, |
| 68 |
int ndx, |
| 69 |
void *p |
| 70 |
) |
| 71 |
{ |
| 72 |
ANGLE_BASIS *ab = (ANGLE_BASIS *)p; |
| 73 |
int li; |
| 74 |
double alt, azi, d; |
| 75 |
|
| 76 |
if ((ndx < 0) | (ndx >= ab->nangles)) |
| 77 |
return(0); |
| 78 |
for (li = 0; ndx >= ab->lat[li].nphis; li++) |
| 79 |
ndx -= ab->lat[li].nphis; |
| 80 |
alt = PI/180.*0.5*(ab->lat[li].tmin + ab->lat[li+1].tmin); |
| 81 |
azi = 2.*PI*ndx/ab->lat[li].nphis; |
| 82 |
v[2] = d = cos(alt); |
| 83 |
d = sqrt(1. - d*d); /* sin(alt) */ |
| 84 |
v[0] = cos(azi)*d; |
| 85 |
v[1] = sin(azi)*d; |
| 86 |
return(1); |
| 87 |
} |
| 88 |
|
| 89 |
|
| 90 |
static int |
| 91 |
ab_getndx( /* get index corresponding to the given vector */ |
| 92 |
FVECT v, |
| 93 |
void *p |
| 94 |
) |
| 95 |
{ |
| 96 |
ANGLE_BASIS *ab = (ANGLE_BASIS *)p; |
| 97 |
int li, ndx; |
| 98 |
double alt, azi, d; |
| 99 |
|
| 100 |
if ((v[2] < -1.0) | (v[2] > 1.0)) |
| 101 |
return(-1); |
| 102 |
alt = 180.0/PI*acos(v[2]); |
| 103 |
azi = 180.0/PI*atan2(v[1], v[0]); |
| 104 |
if (azi < 0.0) azi += 360.0; |
| 105 |
for (li = 1; ab->lat[li].tmin <= alt; li++) |
| 106 |
if (!ab->lat[li].nphis) |
| 107 |
return(-1); |
| 108 |
--li; |
| 109 |
ndx = (int)((1./360.)*azi*ab->lat[li].nphis + 0.5); |
| 110 |
if (ndx >= ab->lat[li].nphis) ndx = 0; |
| 111 |
while (li--) |
| 112 |
ndx += ab->lat[li].nphis; |
| 113 |
return(ndx); |
| 114 |
} |
| 115 |
|
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|
| 117 |
static double |
| 118 |
ab_getohm( /* get solid angle for this angle basis index */ |
| 119 |
int ndx, |
| 120 |
void *p |
| 121 |
) |
| 122 |
{ |
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ANGLE_BASIS *ab = (ANGLE_BASIS *)p; |
| 124 |
int li; |
| 125 |
double theta, theta1; |
| 126 |
|
| 127 |
if ((ndx < 0) | (ndx >= ab->nangles)) |
| 128 |
return(0); |
| 129 |
for (li = 0; ndx >= ab->lat[li].nphis; li++) |
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ndx -= ab->lat[li].nphis; |
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theta1 = PI/180. * ab->lat[li+1].tmin; |
| 132 |
if (ab->lat[li].nphis == 1) { /* special case */ |
| 133 |
if (ab->lat[li].tmin > FTINY) |
| 134 |
error(USER, "unsupported BSDF coordinate system"); |
| 135 |
return(2.*PI*(1. - cos(theta1))); |
| 136 |
} |
| 137 |
theta = PI/180. * ab->lat[li].tmin; |
| 138 |
return(2.*PI*(cos(theta) - cos(theta1))/(double)ab->lat[li].nphis); |
| 139 |
} |
| 140 |
|
| 141 |
|
| 142 |
static int |
| 143 |
ab_getvecR( /* get reverse vector for this angle basis index */ |
| 144 |
FVECT v, |
| 145 |
int ndx, |
| 146 |
void *p |
| 147 |
) |
| 148 |
{ |
| 149 |
if (!ab_getvec(v, ndx, p)) |
| 150 |
return(0); |
| 151 |
|
| 152 |
v[0] = -v[0]; |
| 153 |
v[1] = -v[1]; |
| 154 |
v[2] = -v[2]; |
| 155 |
|
| 156 |
return(1); |
| 157 |
} |
| 158 |
|
| 159 |
|
| 160 |
static int |
| 161 |
ab_getndxR( /* get index corresponding to the reverse vector */ |
| 162 |
FVECT v, |
| 163 |
void *p |
| 164 |
) |
| 165 |
{ |
| 166 |
FVECT v2; |
| 167 |
|
| 168 |
v2[0] = -v[0]; |
| 169 |
v2[1] = -v[1]; |
| 170 |
v2[2] = -v[2]; |
| 171 |
|
| 172 |
return ab_getndx(v2, p); |
| 173 |
} |
| 174 |
|
| 175 |
|
| 176 |
static void |
| 177 |
load_bsdf_data( /* load BSDF distribution for this wavelength */ |
| 178 |
struct BSDF_data *dp, |
| 179 |
ezxml_t wdb |
| 180 |
) |
| 181 |
{ |
| 182 |
char *cbasis = ezxml_txt(ezxml_child(wdb,"ColumnAngleBasis")); |
| 183 |
char *rbasis = ezxml_txt(ezxml_child(wdb,"RowAngleBasis")); |
| 184 |
char *sdata; |
| 185 |
int i; |
| 186 |
|
| 187 |
if ((cbasis == NULL) | (rbasis == NULL)) { |
| 188 |
error(WARNING, "missing column/row basis for BSDF"); |
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return; |
| 190 |
} |
| 191 |
/* XXX need to add routines for loading in foreign bases */ |
| 192 |
for (i = nabases; i--; ) |
| 193 |
if (!strcmp(cbasis, abase_list[i].name)) { |
| 194 |
dp->ninc = abase_list[i].nangles; |
| 195 |
dp->ib_priv = (void *)&abase_list[i]; |
| 196 |
dp->ib_vec = ab_getvecR; |
| 197 |
dp->ib_ndx = ab_getndxR; |
| 198 |
dp->ib_ohm = ab_getohm; |
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break; |
| 200 |
} |
| 201 |
if (i < 0) { |
| 202 |
sprintf(errmsg, "unsupported ColumnAngleBasis '%s'", cbasis); |
| 203 |
error(WARNING, errmsg); |
| 204 |
return; |
| 205 |
} |
| 206 |
for (i = nabases; i--; ) |
| 207 |
if (!strcmp(rbasis, abase_list[i].name)) { |
| 208 |
dp->nout = abase_list[i].nangles; |
| 209 |
dp->ob_priv = (void *)&abase_list[i]; |
| 210 |
dp->ob_vec = ab_getvec; |
| 211 |
dp->ob_ndx = ab_getndx; |
| 212 |
dp->ob_ohm = ab_getohm; |
| 213 |
break; |
| 214 |
} |
| 215 |
if (i < 0) { |
| 216 |
sprintf(errmsg, "unsupported RowAngleBasis '%s'", cbasis); |
| 217 |
error(WARNING, errmsg); |
| 218 |
return; |
| 219 |
} |
| 220 |
/* read BSDF data */ |
| 221 |
sdata = ezxml_txt(ezxml_child(wdb,"ScatteringData")); |
| 222 |
if (sdata == NULL) { |
| 223 |
error(WARNING, "missing BSDF ScatteringData"); |
| 224 |
return; |
| 225 |
} |
| 226 |
dp->bsdf = (float *)malloc(sizeof(float)*dp->ninc*dp->nout); |
| 227 |
if (dp->bsdf == NULL) |
| 228 |
error(SYSTEM, "out of memory in load_bsdf_data"); |
| 229 |
for (i = 0; i < dp->ninc*dp->nout; i++) { |
| 230 |
char *sdnext = fskip(sdata); |
| 231 |
if (sdnext == NULL) { |
| 232 |
error(WARNING, "bad/missing BSDF ScatteringData"); |
| 233 |
free(dp->bsdf); dp->bsdf = NULL; |
| 234 |
return; |
| 235 |
} |
| 236 |
while (*sdnext && isspace(*sdnext)) |
| 237 |
sdnext++; |
| 238 |
if (*sdnext == ',') sdnext++; |
| 239 |
dp->bsdf[i] = atof(sdata); |
| 240 |
sdata = sdnext; |
| 241 |
} |
| 242 |
while (isspace(*sdata)) |
| 243 |
sdata++; |
| 244 |
if (*sdata) { |
| 245 |
sprintf(errmsg, "%d extra characters after BSDF ScatteringData", |
| 246 |
strlen(sdata)); |
| 247 |
error(WARNING, errmsg); |
| 248 |
} |
| 249 |
} |
| 250 |
|
| 251 |
|
| 252 |
static int |
| 253 |
check_bsdf_data( /* check that BSDF data is sane */ |
| 254 |
struct BSDF_data *dp |
| 255 |
) |
| 256 |
{ |
| 257 |
double * omega_arr; |
| 258 |
double dom, hemi_total; |
| 259 |
int nneg; |
| 260 |
int i, o; |
| 261 |
|
| 262 |
if (dp == NULL || dp->bsdf == NULL) |
| 263 |
return(0); |
| 264 |
omega_arr = (double *)calloc(dp->nout, sizeof(double)); |
| 265 |
if (omega_arr == NULL) |
| 266 |
error(SYSTEM, "out of memory in check_bsdf_data"); |
| 267 |
hemi_total = .0; |
| 268 |
for (o = dp->nout; o--; ) { |
| 269 |
FVECT v; |
| 270 |
dom = getBSDF_outohm(dp,o); |
| 271 |
if (dom <= .0) { |
| 272 |
error(WARNING, "zero/negative solid angle"); |
| 273 |
continue; |
| 274 |
} |
| 275 |
if (!getBSDF_outvec(v,dp,o) || v[2] < -FTINY) { |
| 276 |
error(WARNING, "illegal outgoing BSDF direction"); |
| 277 |
free(omega_arr); |
| 278 |
return(0); |
| 279 |
} |
| 280 |
hemi_total += omega_arr[o] = dom*v[2]; |
| 281 |
} |
| 282 |
if ((hemi_total > 1.02*PI) | (hemi_total < 0.98*PI)) { |
| 283 |
sprintf(errmsg, "outgoing BSDF hemisphere off by %.1f%%", |
| 284 |
100.*(hemi_total/PI - 1.)); |
| 285 |
error(WARNING, errmsg); |
| 286 |
} |
| 287 |
dom = PI / hemi_total; /* normalize solid angles */ |
| 288 |
for (o = dp->nout; o--; ) |
| 289 |
omega_arr[o] *= dom; |
| 290 |
nneg = 0; |
| 291 |
for (i = dp->ninc; i--; ) { |
| 292 |
hemi_total = .0; |
| 293 |
for (o = dp->nout; o--; ) { |
| 294 |
double f = BSDF_value(dp,i,o); |
| 295 |
if (f > .0) |
| 296 |
hemi_total += f*omega_arr[o]; |
| 297 |
else if (f < -FTINY) |
| 298 |
++nneg; |
| 299 |
} |
| 300 |
if (hemi_total > 1.02) { |
| 301 |
sprintf(errmsg, "BSDF direction passes %.1f%% of light", |
| 302 |
100.*hemi_total); |
| 303 |
error(WARNING, errmsg); |
| 304 |
} |
| 305 |
} |
| 306 |
free(omega_arr); |
| 307 |
if (nneg > 0) { |
| 308 |
sprintf(errmsg, "%d negative BSDF values", nneg); |
| 309 |
error(WARNING, errmsg); |
| 310 |
return(0); |
| 311 |
} |
| 312 |
return(1); |
| 313 |
} |
| 314 |
|
| 315 |
struct BSDF_data * |
| 316 |
load_BSDF( /* load BSDF data from file */ |
| 317 |
char *fname |
| 318 |
) |
| 319 |
{ |
| 320 |
char *path; |
| 321 |
ezxml_t fl, wtl, wld, wdb; |
| 322 |
struct BSDF_data *dp; |
| 323 |
|
| 324 |
path = getpath(fname, getrlibpath(), R_OK); |
| 325 |
if (path == NULL) { |
| 326 |
sprintf(errmsg, "cannot find BSDF file \"%s\"", fname); |
| 327 |
error(WARNING, errmsg); |
| 328 |
return(NULL); |
| 329 |
} |
| 330 |
fl = ezxml_parse_file(path); |
| 331 |
if (fl == NULL) { |
| 332 |
sprintf(errmsg, "cannot open BSDF \"%s\"", path); |
| 333 |
error(WARNING, errmsg); |
| 334 |
return(NULL); |
| 335 |
} |
| 336 |
if (ezxml_error(fl)[0]) { |
| 337 |
sprintf(errmsg, "BSDF \"%s\" %s", path, ezxml_error(fl)); |
| 338 |
error(WARNING, errmsg); |
| 339 |
ezxml_free(fl); |
| 340 |
return(NULL); |
| 341 |
} |
| 342 |
if (strcmp(ezxml_name(fl), "WindowElement")) { |
| 343 |
sprintf(errmsg, |
| 344 |
"BSDF \"%s\": top level node not 'WindowElement'", |
| 345 |
path); |
| 346 |
error(WARNING, errmsg); |
| 347 |
ezxml_free(fl); |
| 348 |
return(NULL); |
| 349 |
} |
| 350 |
wtl = ezxml_child(ezxml_child(fl, "Optical"), "Layer"); |
| 351 |
dp = (struct BSDF_data *)calloc(1, sizeof(struct BSDF_data)); |
| 352 |
for (wld = ezxml_child(wtl, "WavelengthData"); |
| 353 |
wld != NULL; wld = wld->next) { |
| 354 |
if (strcmp(ezxml_txt(ezxml_child(wld,"Wavelength")), "Visible")) |
| 355 |
continue; |
| 356 |
wdb = ezxml_child(wld, "WavelengthDataBlock"); |
| 357 |
if (wdb == NULL) continue; |
| 358 |
if (strcmp(ezxml_txt(ezxml_child(wdb,"WavelengthDataDirection")), |
| 359 |
"Transmission Front")) |
| 360 |
continue; |
| 361 |
load_bsdf_data(dp, wdb); /* load front BTDF */ |
| 362 |
break; /* ignore the rest */ |
| 363 |
} |
| 364 |
ezxml_free(fl); /* done with XML file */ |
| 365 |
if (!check_bsdf_data(dp)) { |
| 366 |
sprintf(errmsg, "bad/missing BTDF data in \"%s\"", path); |
| 367 |
error(WARNING, errmsg); |
| 368 |
free_BSDF(dp); |
| 369 |
dp = NULL; |
| 370 |
} |
| 371 |
return(dp); |
| 372 |
} |
| 373 |
|
| 374 |
|
| 375 |
void |
| 376 |
free_BSDF( /* free BSDF data structure */ |
| 377 |
struct BSDF_data *b |
| 378 |
) |
| 379 |
{ |
| 380 |
if (b == NULL) |
| 381 |
return; |
| 382 |
if (b->bsdf != NULL) |
| 383 |
free(b->bsdf); |
| 384 |
free(b); |
| 385 |
} |
| 386 |
|
| 387 |
|
| 388 |
int |
| 389 |
r_BSDF_incvec( /* compute random input vector at given location */ |
| 390 |
FVECT v, |
| 391 |
struct BSDF_data *b, |
| 392 |
int i, |
| 393 |
double rv, |
| 394 |
MAT4 xm |
| 395 |
) |
| 396 |
{ |
| 397 |
FVECT pert; |
| 398 |
double rad; |
| 399 |
int j; |
| 400 |
|
| 401 |
if (!getBSDF_incvec(v, b, i)) |
| 402 |
return(0); |
| 403 |
rad = sqrt(getBSDF_incohm(b, i) / PI); |
| 404 |
multisamp(pert, 3, rv); |
| 405 |
for (j = 0; j < 3; j++) |
| 406 |
v[j] += rad*(2.*pert[j] - 1.); |
| 407 |
if (xm != NULL) |
| 408 |
multv3(v, v, xm); |
| 409 |
return(normalize(v) != 0.0); |
| 410 |
} |
| 411 |
|
| 412 |
|
| 413 |
int |
| 414 |
r_BSDF_outvec( /* compute random output vector at given location */ |
| 415 |
FVECT v, |
| 416 |
struct BSDF_data *b, |
| 417 |
int o, |
| 418 |
double rv, |
| 419 |
MAT4 xm |
| 420 |
) |
| 421 |
{ |
| 422 |
FVECT pert; |
| 423 |
double rad; |
| 424 |
int j; |
| 425 |
|
| 426 |
if (!getBSDF_outvec(v, b, o)) |
| 427 |
return(0); |
| 428 |
rad = sqrt(getBSDF_outohm(b, o) / PI); |
| 429 |
multisamp(pert, 3, rv); |
| 430 |
for (j = 0; j < 3; j++) |
| 431 |
v[j] += rad*(2.*pert[j] - 1.); |
| 432 |
if (xm != NULL) |
| 433 |
multv3(v, v, xm); |
| 434 |
return(normalize(v) != 0.0); |
| 435 |
} |
| 436 |
|
| 437 |
|
| 438 |
#define FEQ(a,b) ((a)-(b) <= 1e-7 && (b)-(a) <= 1e-7) |
| 439 |
|
| 440 |
static int |
| 441 |
addrot( /* compute rotation (x,y,z) => (xp,yp,zp) */ |
| 442 |
char *xfarg[], |
| 443 |
FVECT xp, |
| 444 |
FVECT yp, |
| 445 |
FVECT zp |
| 446 |
) |
| 447 |
{ |
| 448 |
static char bufs[3][16]; |
| 449 |
int bn = 0; |
| 450 |
char **xfp = xfarg; |
| 451 |
double theta; |
| 452 |
|
| 453 |
if (yp[2]*yp[2] + zp[2]*zp[2] < 2.*FTINY*FTINY) { |
| 454 |
/* Special case for X' along Z-axis */ |
| 455 |
theta = -atan2(yp[0], yp[1]); |
| 456 |
*xfp++ = "-ry"; |
| 457 |
*xfp++ = xp[2] < 0.0 ? "90" : "-90"; |
| 458 |
*xfp++ = "-rz"; |
| 459 |
sprintf(bufs[bn], "%f", theta*(180./PI)); |
| 460 |
*xfp++ = bufs[bn++]; |
| 461 |
return(xfp - xfarg); |
| 462 |
} |
| 463 |
theta = atan2(yp[2], zp[2]); |
| 464 |
if (!FEQ(theta,0.0)) { |
| 465 |
*xfp++ = "-rx"; |
| 466 |
sprintf(bufs[bn], "%f", theta*(180./PI)); |
| 467 |
*xfp++ = bufs[bn++]; |
| 468 |
} |
| 469 |
theta = asin(-xp[2]); |
| 470 |
if (!FEQ(theta,0.0)) { |
| 471 |
*xfp++ = "-ry"; |
| 472 |
sprintf(bufs[bn], " %f", theta*(180./PI)); |
| 473 |
*xfp++ = bufs[bn++]; |
| 474 |
} |
| 475 |
theta = atan2(xp[1], xp[0]); |
| 476 |
if (!FEQ(theta,0.0)) { |
| 477 |
*xfp++ = "-rz"; |
| 478 |
sprintf(bufs[bn], "%f", theta*(180./PI)); |
| 479 |
*xfp++ = bufs[bn++]; |
| 480 |
} |
| 481 |
*xfp = NULL; |
| 482 |
return(xfp - xfarg); |
| 483 |
} |
| 484 |
|
| 485 |
|
| 486 |
int |
| 487 |
getBSDF_xfm( /* compute BSDF orient. -> world orient. transform */ |
| 488 |
MAT4 xm, |
| 489 |
FVECT nrm, |
| 490 |
UpDir ud |
| 491 |
) |
| 492 |
{ |
| 493 |
char *xfargs[7]; |
| 494 |
XF myxf; |
| 495 |
FVECT updir, xdest, ydest; |
| 496 |
|
| 497 |
updir[0] = updir[1] = updir[2] = 0.; |
| 498 |
switch (ud) { |
| 499 |
case UDzneg: |
| 500 |
updir[2] = -1.; |
| 501 |
break; |
| 502 |
case UDyneg: |
| 503 |
updir[1] = -1.; |
| 504 |
break; |
| 505 |
case UDxneg: |
| 506 |
updir[0] = -1.; |
| 507 |
break; |
| 508 |
case UDxpos: |
| 509 |
updir[0] = 1.; |
| 510 |
break; |
| 511 |
case UDypos: |
| 512 |
updir[1] = 1.; |
| 513 |
break; |
| 514 |
case UDzpos: |
| 515 |
updir[2] = 1.; |
| 516 |
break; |
| 517 |
case UDunknown: |
| 518 |
return(0); |
| 519 |
} |
| 520 |
fcross(xdest, updir, nrm); |
| 521 |
if (normalize(xdest) == 0.0) |
| 522 |
return(0); |
| 523 |
fcross(ydest, nrm, xdest); |
| 524 |
xf(&myxf, addrot(xfargs, xdest, ydest, nrm), xfargs); |
| 525 |
copymat4(xm, myxf.xfm); |
| 526 |
return(1); |
| 527 |
} |
