| 1 |
/* |
| 2 |
* bsdf_m.c |
| 3 |
* |
| 4 |
* Definitions supporting BSDF matrices |
| 5 |
* |
| 6 |
* Created by Greg Ward on 2/2/11. |
| 7 |
* Copyright 2011 Anyhere Software. All rights reserved. |
| 8 |
* |
| 9 |
*/ |
| 10 |
|
| 11 |
#include <stdio.h> |
| 12 |
#include <stdlib.h> |
| 13 |
#include <math.h> |
| 14 |
#include <strings.h> |
| 15 |
#include <ctype.h> |
| 16 |
#include "ezxml.h" |
| 17 |
#include "bsdf.h" |
| 18 |
#include "bsdf_m.h" |
| 19 |
|
| 20 |
#ifndef FTINY |
| 21 |
#define FTINY 1e-6 |
| 22 |
#endif |
| 23 |
|
| 24 |
/* Function return codes */ |
| 25 |
#define RC_GOOD 1 |
| 26 |
#define RC_FAIL 0 |
| 27 |
#define RC_FORMERR (-1) |
| 28 |
#define RC_DATERR (-2) |
| 29 |
#define RC_UNSUPP (-3) |
| 30 |
#define RC_INTERR (-4) |
| 31 |
#define RC_MEMERR (-5) |
| 32 |
|
| 33 |
#define MAXLATS 46 /* maximum number of latitudes */ |
| 34 |
|
| 35 |
/* BSDF angle specification */ |
| 36 |
typedef struct { |
| 37 |
char name[64]; /* basis name */ |
| 38 |
int nangles; /* total number of directions */ |
| 39 |
struct { |
| 40 |
float tmin; /* starting theta */ |
| 41 |
int nphis; /* number of phis (0 term) */ |
| 42 |
} lat[MAXLATS+1]; /* latitudes */ |
| 43 |
} ANGLE_BASIS; |
| 44 |
|
| 45 |
#define MAXABASES 7 /* limit on defined bases */ |
| 46 |
|
| 47 |
static ANGLE_BASIS abase_list[MAXABASES] = { |
| 48 |
{ |
| 49 |
"LBNL/Klems Full", 145, |
| 50 |
{ {-5., 1}, |
| 51 |
{5., 8}, |
| 52 |
{15., 16}, |
| 53 |
{25., 20}, |
| 54 |
{35., 24}, |
| 55 |
{45., 24}, |
| 56 |
{55., 24}, |
| 57 |
{65., 16}, |
| 58 |
{75., 12}, |
| 59 |
{90., 0} } |
| 60 |
}, { |
| 61 |
"LBNL/Klems Half", 73, |
| 62 |
{ {-6.5, 1}, |
| 63 |
{6.5, 8}, |
| 64 |
{19.5, 12}, |
| 65 |
{32.5, 16}, |
| 66 |
{46.5, 20}, |
| 67 |
{61.5, 12}, |
| 68 |
{76.5, 4}, |
| 69 |
{90., 0} } |
| 70 |
}, { |
| 71 |
"LBNL/Klems Quarter", 41, |
| 72 |
{ {-9., 1}, |
| 73 |
{9., 8}, |
| 74 |
{27., 12}, |
| 75 |
{46., 12}, |
| 76 |
{66., 8}, |
| 77 |
{90., 0} } |
| 78 |
} |
| 79 |
}; |
| 80 |
|
| 81 |
static int nabases = 3; /* current number of defined bases */ |
| 82 |
|
| 83 |
static int |
| 84 |
fequal(double a, double b) |
| 85 |
{ |
| 86 |
if (b != .0) |
| 87 |
a = a/b - 1.; |
| 88 |
return (a <= 1e-6) & (a >= -1e-6); |
| 89 |
} |
| 90 |
|
| 91 |
/* returns the name of the given tag */ |
| 92 |
#ifdef ezxml_name |
| 93 |
#undef ezxml_name |
| 94 |
static char * |
| 95 |
ezxml_name(ezxml_t xml) |
| 96 |
{ |
| 97 |
if (xml == NULL) |
| 98 |
return NULL; |
| 99 |
return xml->name; |
| 100 |
} |
| 101 |
#endif |
| 102 |
|
| 103 |
/* returns the given tag's character content or empty string if none */ |
| 104 |
#ifdef ezxml_txt |
| 105 |
#undef ezxml_txt |
| 106 |
static char * |
| 107 |
ezxml_txt(ezxml_t xml) |
| 108 |
{ |
| 109 |
if (xml == NULL) |
| 110 |
return ""; |
| 111 |
return xml->txt; |
| 112 |
} |
| 113 |
#endif |
| 114 |
|
| 115 |
/* Convert error to standard BSDF code */ |
| 116 |
static SDError |
| 117 |
convert_errcode(int ec) |
| 118 |
{ |
| 119 |
switch (ec) { |
| 120 |
case RC_GOOD: |
| 121 |
return SDEnone; |
| 122 |
case RC_FORMERR: |
| 123 |
return SDEformat; |
| 124 |
case RC_DATERR: |
| 125 |
return SDEdata; |
| 126 |
case RC_UNSUPP: |
| 127 |
return SDEsupport; |
| 128 |
case RC_INTERR: |
| 129 |
return SDEinternal; |
| 130 |
case RC_MEMERR: |
| 131 |
return SDEmemory; |
| 132 |
} |
| 133 |
return SDEunknown; |
| 134 |
} |
| 135 |
|
| 136 |
/* Allocate a BSDF matrix of the given size */ |
| 137 |
static SDMat * |
| 138 |
SDnewMatrix(int ni, int no) |
| 139 |
{ |
| 140 |
SDMat *sm; |
| 141 |
|
| 142 |
if ((ni <= 0) | (no <= 0)) { |
| 143 |
strcpy(SDerrorDetail, "Empty BSDF matrix request"); |
| 144 |
return NULL; |
| 145 |
} |
| 146 |
sm = (SDMat *)malloc(sizeof(SDMat) + (ni*no - 1)*sizeof(float)); |
| 147 |
if (sm == NULL) { |
| 148 |
sprintf(SDerrorDetail, "Cannot allocate %dx%d BSDF matrix", |
| 149 |
ni, no); |
| 150 |
return NULL; |
| 151 |
} |
| 152 |
memset(sm, 0, sizeof(SDMat)-sizeof(float)); |
| 153 |
sm->ninc = ni; |
| 154 |
sm->nout = no; |
| 155 |
|
| 156 |
return sm; |
| 157 |
} |
| 158 |
|
| 159 |
/* Free a BSDF matrix */ |
| 160 |
#define SDfreeMatrix free |
| 161 |
|
| 162 |
/* get vector for this angle basis index */ |
| 163 |
static int |
| 164 |
ab_getvec(FVECT v, int ndx, double randX, void *p) |
| 165 |
{ |
| 166 |
ANGLE_BASIS *ab = (ANGLE_BASIS *)p; |
| 167 |
double rx[2]; |
| 168 |
int li; |
| 169 |
double pol, azi, d; |
| 170 |
|
| 171 |
if ((ndx < 0) | (ndx >= ab->nangles)) |
| 172 |
return RC_FAIL; |
| 173 |
for (li = 0; ndx >= ab->lat[li].nphis; li++) |
| 174 |
ndx -= ab->lat[li].nphis; |
| 175 |
SDmultiSamp(rx, 2, randX); |
| 176 |
pol = M_PI/180.*( (1.-rx[0])*ab->lat[li].tmin + |
| 177 |
rx[0]*ab->lat[li+1].tmin ); |
| 178 |
azi = 2.*M_PI*(ndx + rx[1] - .5)/ab->lat[li].nphis; |
| 179 |
v[2] = d = cos(pol); |
| 180 |
d = sqrt(1. - d*d); /* sin(pol) */ |
| 181 |
v[0] = cos(azi)*d; |
| 182 |
v[1] = sin(azi)*d; |
| 183 |
return RC_GOOD; |
| 184 |
} |
| 185 |
|
| 186 |
/* get index corresponding to the given vector */ |
| 187 |
static int |
| 188 |
ab_getndx(const FVECT v, void *p) |
| 189 |
{ |
| 190 |
ANGLE_BASIS *ab = (ANGLE_BASIS *)p; |
| 191 |
int li, ndx; |
| 192 |
double pol, azi, d; |
| 193 |
|
| 194 |
if (v == NULL) |
| 195 |
return -1; |
| 196 |
if ((v[2] < .0) | (v[2] > 1.0)) |
| 197 |
return -1; |
| 198 |
pol = 180.0/M_PI*acos(v[2]); |
| 199 |
azi = 180.0/M_PI*atan2(v[1], v[0]); |
| 200 |
if (azi < 0.0) azi += 360.0; |
| 201 |
for (li = 1; ab->lat[li].tmin <= pol; li++) |
| 202 |
if (!ab->lat[li].nphis) |
| 203 |
return -1; |
| 204 |
--li; |
| 205 |
ndx = (int)((1./360.)*azi*ab->lat[li].nphis + 0.5); |
| 206 |
if (ndx >= ab->lat[li].nphis) ndx = 0; |
| 207 |
while (li--) |
| 208 |
ndx += ab->lat[li].nphis; |
| 209 |
return ndx; |
| 210 |
} |
| 211 |
|
| 212 |
/* compute square of real value */ |
| 213 |
static double sq(double x) { return x*x; } |
| 214 |
|
| 215 |
/* get projected solid angle for this angle basis index */ |
| 216 |
static double |
| 217 |
ab_getohm(int ndx, void *p) |
| 218 |
{ |
| 219 |
static int last_li = -1; |
| 220 |
static double last_ohm; |
| 221 |
ANGLE_BASIS *ab = (ANGLE_BASIS *)p; |
| 222 |
int li; |
| 223 |
double theta, theta1; |
| 224 |
|
| 225 |
if ((ndx < 0) | (ndx >= ab->nangles)) |
| 226 |
return -1.; |
| 227 |
for (li = 0; ndx >= ab->lat[li].nphis; li++) |
| 228 |
ndx -= ab->lat[li].nphis; |
| 229 |
if (li == last_li) /* cached latitude? */ |
| 230 |
return last_ohm; |
| 231 |
last_li = li; |
| 232 |
theta1 = M_PI/180. * ab->lat[li+1].tmin; |
| 233 |
if (ab->lat[li].nphis == 1) /* special case */ |
| 234 |
return last_ohm = M_PI*(1. - sq(cos(theta1))); |
| 235 |
theta = M_PI/180. * ab->lat[li].tmin; |
| 236 |
return last_ohm = M_PI*(sq(cos(theta)) - sq(cos(theta1))) / |
| 237 |
(double)ab->lat[li].nphis; |
| 238 |
} |
| 239 |
|
| 240 |
/* get reverse vector for this angle basis index */ |
| 241 |
static int |
| 242 |
ab_getvecR(FVECT v, int ndx, double randX, void *p) |
| 243 |
{ |
| 244 |
int na = (*(ANGLE_BASIS *)p).nangles; |
| 245 |
|
| 246 |
if (!ab_getvec(v, ndx, randX, p)) |
| 247 |
return RC_FAIL; |
| 248 |
|
| 249 |
v[0] = -v[0]; |
| 250 |
v[1] = -v[1]; |
| 251 |
v[2] = -v[2]; |
| 252 |
|
| 253 |
return RC_GOOD; |
| 254 |
} |
| 255 |
|
| 256 |
/* get index corresponding to the reverse vector */ |
| 257 |
static int |
| 258 |
ab_getndxR(const FVECT v, void *p) |
| 259 |
{ |
| 260 |
FVECT v2; |
| 261 |
|
| 262 |
v2[0] = -v[0]; |
| 263 |
v2[1] = -v[1]; |
| 264 |
v2[2] = -v[2]; |
| 265 |
|
| 266 |
return ab_getndx(v2, p); |
| 267 |
} |
| 268 |
|
| 269 |
/* load custom BSDF angle basis */ |
| 270 |
static int |
| 271 |
load_angle_basis(ezxml_t wab) |
| 272 |
{ |
| 273 |
char *abname = ezxml_txt(ezxml_child(wab, "AngleBasisName")); |
| 274 |
ezxml_t wbb; |
| 275 |
int i; |
| 276 |
|
| 277 |
if (!abname || !*abname) |
| 278 |
return RC_FAIL; |
| 279 |
for (i = nabases; i--; ) |
| 280 |
if (!strcasecmp(abname, abase_list[i].name)) |
| 281 |
return RC_GOOD; /* assume it's the same */ |
| 282 |
if (nabases >= MAXABASES) { |
| 283 |
sprintf(SDerrorDetail, "Out of angle bases reading '%s'", |
| 284 |
abname); |
| 285 |
return RC_INTERR; |
| 286 |
} |
| 287 |
strcpy(abase_list[nabases].name, abname); |
| 288 |
abase_list[nabases].nangles = 0; |
| 289 |
for (i = 0, wbb = ezxml_child(wab, "AngleBasisBlock"); |
| 290 |
wbb != NULL; i++, wbb = wbb->next) { |
| 291 |
if (i >= MAXLATS) { |
| 292 |
sprintf(SDerrorDetail, "Too many latitudes for '%s'", |
| 293 |
abname); |
| 294 |
return RC_INTERR; |
| 295 |
} |
| 296 |
abase_list[nabases].lat[i+1].tmin = atof(ezxml_txt( |
| 297 |
ezxml_child(ezxml_child(wbb, |
| 298 |
"ThetaBounds"), "UpperTheta"))); |
| 299 |
if (!i) |
| 300 |
abase_list[nabases].lat[i].tmin = |
| 301 |
-abase_list[nabases].lat[i+1].tmin; |
| 302 |
else if (!fequal(atof(ezxml_txt(ezxml_child(ezxml_child(wbb, |
| 303 |
"ThetaBounds"), "LowerTheta"))), |
| 304 |
abase_list[nabases].lat[i].tmin)) { |
| 305 |
sprintf(SDerrorDetail, "Theta values disagree in '%s'", |
| 306 |
abname); |
| 307 |
return RC_DATERR; |
| 308 |
} |
| 309 |
abase_list[nabases].nangles += |
| 310 |
abase_list[nabases].lat[i].nphis = |
| 311 |
atoi(ezxml_txt(ezxml_child(wbb, "nPhis"))); |
| 312 |
if (abase_list[nabases].lat[i].nphis <= 0 || |
| 313 |
(abase_list[nabases].lat[i].nphis == 1 && |
| 314 |
abase_list[nabases].lat[i].tmin > FTINY)) { |
| 315 |
sprintf(SDerrorDetail, "Illegal phi count in '%s'", |
| 316 |
abname); |
| 317 |
return RC_DATERR; |
| 318 |
} |
| 319 |
} |
| 320 |
abase_list[nabases++].lat[i].nphis = 0; |
| 321 |
return RC_GOOD; |
| 322 |
} |
| 323 |
|
| 324 |
/* compute min. proj. solid angle and max. direct hemispherical scattering */ |
| 325 |
static int |
| 326 |
get_extrema(SDSpectralDF *df) |
| 327 |
{ |
| 328 |
SDMat *dp = (SDMat *)df->comp[0].dist; |
| 329 |
double *ohma; |
| 330 |
int i, o; |
| 331 |
/* initialize extrema */ |
| 332 |
df->minProjSA = M_PI; |
| 333 |
df->maxHemi = .0; |
| 334 |
ohma = (double *)malloc(dp->nout*sizeof(double)); |
| 335 |
if (ohma == NULL) |
| 336 |
return RC_MEMERR; |
| 337 |
/* get outgoing solid angles */ |
| 338 |
for (o = dp->nout; o--; ) |
| 339 |
if ((ohma[o] = mBSDF_outohm(dp,o)) < df->minProjSA) |
| 340 |
df->minProjSA = ohma[o]; |
| 341 |
/* compute hemispherical sums */ |
| 342 |
for (i = dp->ninc; i--; ) { |
| 343 |
double hemi = .0; |
| 344 |
for (o = dp->nout; o--; ) |
| 345 |
hemi += ohma[o] * mBSDF_value(dp, i, o); |
| 346 |
if (hemi > df->maxHemi) |
| 347 |
df->maxHemi = hemi; |
| 348 |
} |
| 349 |
free(ohma); |
| 350 |
/* need incoming solid angles, too? */ |
| 351 |
if (dp->ninc < dp->nout || dp->ib_ohm != dp->ob_ohm || |
| 352 |
dp->ib_priv != dp->ob_priv) { |
| 353 |
double ohm; |
| 354 |
for (i = dp->ninc; i--; ) |
| 355 |
if ((ohm = mBSDF_incohm(dp,i)) < df->minProjSA) |
| 356 |
df->minProjSA = ohm; |
| 357 |
} |
| 358 |
return (df->maxHemi <= 1.01); |
| 359 |
} |
| 360 |
|
| 361 |
/* skip integer in string */ |
| 362 |
static char * |
| 363 |
i_skip(char *s) |
| 364 |
{ |
| 365 |
while (isspace(*s)) |
| 366 |
s++; |
| 367 |
if (*s == '-' || *s == '+') |
| 368 |
s++; |
| 369 |
if (!isdigit(*s)) |
| 370 |
return(NULL); |
| 371 |
do |
| 372 |
s++; |
| 373 |
while (isdigit(*s)); |
| 374 |
return(s); |
| 375 |
} |
| 376 |
|
| 377 |
/* skip float in string */ |
| 378 |
static char * |
| 379 |
f_skip(char *s) |
| 380 |
{ |
| 381 |
register char *cp; |
| 382 |
|
| 383 |
while (isspace(*s)) |
| 384 |
s++; |
| 385 |
if (*s == '-' || *s == '+') |
| 386 |
s++; |
| 387 |
cp = s; |
| 388 |
while (isdigit(*cp)) |
| 389 |
cp++; |
| 390 |
if (*cp == '.') { |
| 391 |
cp++; s++; |
| 392 |
while (isdigit(*cp)) |
| 393 |
cp++; |
| 394 |
} |
| 395 |
if (cp == s) |
| 396 |
return(NULL); |
| 397 |
if (*cp == 'e' || *cp == 'E') |
| 398 |
return(i_skip(cp+1)); |
| 399 |
return(cp); |
| 400 |
} |
| 401 |
|
| 402 |
/* load BSDF distribution for this wavelength */ |
| 403 |
static int |
| 404 |
load_bsdf_data(SDData *sd, ezxml_t wdb, int rowinc) |
| 405 |
{ |
| 406 |
char *cbasis = ezxml_txt(ezxml_child(wdb,"ColumnAngleBasis")); |
| 407 |
char *rbasis = ezxml_txt(ezxml_child(wdb,"RowAngleBasis")); |
| 408 |
SDSpectralDF *df; |
| 409 |
SDMat *dp; |
| 410 |
char *sdata; |
| 411 |
int inbi, outbi; |
| 412 |
int i; |
| 413 |
|
| 414 |
if ((!cbasis || !*cbasis) | (!rbasis || !*rbasis)) { |
| 415 |
sprintf(SDerrorDetail, "Missing column/row basis for BSDF '%s'", |
| 416 |
sd->name); |
| 417 |
return RC_FORMERR; |
| 418 |
} |
| 419 |
/* allocate BSDF component */ |
| 420 |
sdata = ezxml_txt(ezxml_child(wdb, "WavelengthDataDirection")); |
| 421 |
if (!strcasecmp(sdata, "Transmission Front")) { |
| 422 |
if (sd->tf != NULL) |
| 423 |
SDfreeSpectralDF(sd->tf); |
| 424 |
if ((sd->tf = SDnewSpectralDF(1)) == NULL) |
| 425 |
return RC_MEMERR; |
| 426 |
df = sd->tf; |
| 427 |
} else if (!strcasecmp(sdata, "Reflection Front")) { |
| 428 |
if (sd->rf != NULL) |
| 429 |
SDfreeSpectralDF(sd->rf); |
| 430 |
if ((sd->rf = SDnewSpectralDF(1)) == NULL) |
| 431 |
return RC_MEMERR; |
| 432 |
df = sd->rf; |
| 433 |
} else if (!strcasecmp(sdata, "Reflection Back")) { |
| 434 |
if (sd->rb != NULL) |
| 435 |
SDfreeSpectralDF(sd->rb); |
| 436 |
if ((sd->rb = SDnewSpectralDF(1)) == NULL) |
| 437 |
return RC_MEMERR; |
| 438 |
df = sd->rb; |
| 439 |
} else |
| 440 |
return RC_FAIL; |
| 441 |
/* get angle bases */ |
| 442 |
sdata = ezxml_txt(ezxml_child(wdb,"ColumnAngleBasis")); |
| 443 |
if (!sdata || !*sdata) { |
| 444 |
sprintf(SDerrorDetail, "Missing column basis for BSDF '%s'", |
| 445 |
sd->name); |
| 446 |
return RC_FORMERR; |
| 447 |
} |
| 448 |
for (inbi = nabases; inbi--; ) |
| 449 |
if (!strcasecmp(cbasis, abase_list[inbi].name)) |
| 450 |
break; |
| 451 |
if (inbi < 0) { |
| 452 |
sprintf(SDerrorDetail, "Undefined ColumnAngleBasis '%s'", |
| 453 |
cbasis); |
| 454 |
return RC_FORMERR; |
| 455 |
} |
| 456 |
sdata = ezxml_txt(ezxml_child(wdb,"RowAngleBasis")); |
| 457 |
if (!sdata || !*sdata) { |
| 458 |
sprintf(SDerrorDetail, "Missing row basis for BSDF '%s'", |
| 459 |
sd->name); |
| 460 |
return RC_FORMERR; |
| 461 |
} |
| 462 |
for (outbi = nabases; outbi--; ) |
| 463 |
if (!strcasecmp(rbasis, abase_list[outbi].name)) |
| 464 |
break; |
| 465 |
if (outbi < 0) { |
| 466 |
sprintf(SDerrorDetail, "Undefined RowAngleBasis '%s'", cbasis); |
| 467 |
return RC_FORMERR; |
| 468 |
} |
| 469 |
/* allocate BSDF matrix */ |
| 470 |
dp = SDnewMatrix(abase_list[inbi].nangles, abase_list[outbi].nangles); |
| 471 |
if (dp == NULL) |
| 472 |
return RC_MEMERR; |
| 473 |
dp->ib_priv = (void *)&abase_list[inbi]; |
| 474 |
dp->ob_priv = (void *)&abase_list[outbi]; |
| 475 |
if (df == sd->tf) { |
| 476 |
dp->ib_vec = ab_getvecR; |
| 477 |
dp->ib_ndx = ab_getndxR; |
| 478 |
dp->ob_vec = ab_getvec; |
| 479 |
dp->ob_ndx = ab_getndx; |
| 480 |
} else if (df == sd->rf) { |
| 481 |
dp->ib_vec = ab_getvec; |
| 482 |
dp->ib_ndx = ab_getndx; |
| 483 |
dp->ob_vec = ab_getvec; |
| 484 |
dp->ob_ndx = ab_getndx; |
| 485 |
} else /* df == sd->rb */ { |
| 486 |
dp->ib_vec = ab_getvecR; |
| 487 |
dp->ib_ndx = ab_getndxR; |
| 488 |
dp->ob_vec = ab_getvecR; |
| 489 |
dp->ob_ndx = ab_getndxR; |
| 490 |
} |
| 491 |
dp->ib_ohm = ab_getohm; |
| 492 |
dp->ob_ohm = ab_getohm; |
| 493 |
df->comp[0].cspec[0] = c_dfcolor; /* XXX monochrome for now */ |
| 494 |
df->comp[0].dist = dp; |
| 495 |
df->comp[0].func = &SDhandleMtx; |
| 496 |
/* read BSDF data */ |
| 497 |
sdata = ezxml_txt(ezxml_child(wdb,"ScatteringData")); |
| 498 |
if (!sdata || !*sdata) { |
| 499 |
sprintf(SDerrorDetail, "Missing BSDF ScatteringData in '%s'", |
| 500 |
sd->name); |
| 501 |
return RC_FORMERR; |
| 502 |
} |
| 503 |
for (i = 0; i < dp->ninc*dp->nout; i++) { |
| 504 |
char *sdnext = f_skip(sdata); |
| 505 |
if (sdnext == NULL) { |
| 506 |
sprintf(SDerrorDetail, |
| 507 |
"Bad/missing BSDF ScatteringData in '%s'", |
| 508 |
sd->name); |
| 509 |
return RC_FORMERR; |
| 510 |
} |
| 511 |
while (*sdnext && isspace(*sdnext)) |
| 512 |
sdnext++; |
| 513 |
if (*sdnext == ',') sdnext++; |
| 514 |
if (rowinc) { |
| 515 |
int r = i/dp->nout; |
| 516 |
int c = i - c*dp->nout; |
| 517 |
mBSDF_value(dp,r,c) = atof(sdata); |
| 518 |
} else |
| 519 |
dp->bsdf[i] = atof(sdata); |
| 520 |
sdata = sdnext; |
| 521 |
} |
| 522 |
return get_extrema(df); |
| 523 |
} |
| 524 |
|
| 525 |
/* Subtract minimum (diffuse) scattering amount from BSDF */ |
| 526 |
static double |
| 527 |
subtract_min(SDMat *sm) |
| 528 |
{ |
| 529 |
float minv = sm->bsdf[0]; |
| 530 |
int n = sm->ninc*sm->nout; |
| 531 |
int i; |
| 532 |
|
| 533 |
for (i = n; --i; ) |
| 534 |
if (sm->bsdf[i] < minv) |
| 535 |
minv = sm->bsdf[i]; |
| 536 |
for (i = n; i--; ) |
| 537 |
sm->bsdf[i] -= minv; |
| 538 |
|
| 539 |
return minv*M_PI; /* be sure to include multiplier */ |
| 540 |
} |
| 541 |
|
| 542 |
/* Extract and separate diffuse portion of BSDF */ |
| 543 |
static void |
| 544 |
extract_diffuse(SDValue *dv, SDSpectralDF *df) |
| 545 |
{ |
| 546 |
int n; |
| 547 |
|
| 548 |
if (df == NULL || df->ncomp <= 0) { |
| 549 |
dv->spec = c_dfcolor; |
| 550 |
dv->cieY = .0; |
| 551 |
return; |
| 552 |
} |
| 553 |
dv->spec = df->comp[0].cspec[0]; |
| 554 |
dv->cieY = subtract_min((SDMat *)df->comp[0].dist); |
| 555 |
/* in case of multiple components */ |
| 556 |
for (n = df->ncomp; --n; ) { |
| 557 |
double ymin = subtract_min((SDMat *)df->comp[n].dist); |
| 558 |
c_cmix(&dv->spec, dv->cieY, &dv->spec, ymin, &df->comp[n].cspec[0]); |
| 559 |
dv->cieY += ymin; |
| 560 |
} |
| 561 |
df->maxHemi -= dv->cieY; /* correct minimum hemispherical */ |
| 562 |
dv->spec.clock++; /* make sure everything is set */ |
| 563 |
c_ccvt(&dv->spec, C_CSXY+C_CSSPEC); |
| 564 |
} |
| 565 |
|
| 566 |
/* Load a BSDF matrix from an open XML file */ |
| 567 |
SDError |
| 568 |
SDloadMtx(SDData *sd, ezxml_t fl) |
| 569 |
{ |
| 570 |
ezxml_t wtl, wld, wdb; |
| 571 |
int rowIn; |
| 572 |
struct BSDF_data *dp; |
| 573 |
char *txt; |
| 574 |
int rval; |
| 575 |
|
| 576 |
if (strcmp(ezxml_name(fl), "WindowElement")) { |
| 577 |
sprintf(SDerrorDetail, |
| 578 |
"BSDF \"%s\": top level node not 'WindowElement'", |
| 579 |
sd->name); |
| 580 |
return SDEformat; |
| 581 |
} |
| 582 |
wtl = ezxml_child(ezxml_child(fl, "Optical"), "Layer"); |
| 583 |
txt = ezxml_txt(ezxml_child(ezxml_child(wtl, |
| 584 |
"DataDefinition"), "IncidentDataStructure")); |
| 585 |
if (!strcasecmp(txt, "Rows")) |
| 586 |
rowIn = 1; |
| 587 |
else if (!strcasecmp(txt, "Columns")) |
| 588 |
rowIn = 0; |
| 589 |
else { |
| 590 |
sprintf(SDerrorDetail, |
| 591 |
"BSDF \"%s\": unsupported IncidentDataStructure", |
| 592 |
sd->name); |
| 593 |
return SDEsupport; |
| 594 |
} |
| 595 |
/* get angle basis */ |
| 596 |
rval = load_angle_basis(ezxml_child(ezxml_child(wtl, |
| 597 |
"DataDefinition"), "AngleBasis")); |
| 598 |
if (rval < 0) |
| 599 |
goto err_return; |
| 600 |
/* load BSDF components */ |
| 601 |
for (wld = ezxml_child(wtl, "WavelengthData"); |
| 602 |
wld != NULL; wld = wld->next) { |
| 603 |
if (strcasecmp(ezxml_txt(ezxml_child(wld,"Wavelength")), |
| 604 |
"Visible")) |
| 605 |
continue; /* just visible for now */ |
| 606 |
for (wdb = ezxml_child(wld, "WavelengthDataBlock"); |
| 607 |
wdb != NULL; wdb = wdb->next) |
| 608 |
if ((rval = load_bsdf_data(sd, wdb, rowIn)) < 0) |
| 609 |
goto err_return; |
| 610 |
} |
| 611 |
/* separate diffuse components */ |
| 612 |
extract_diffuse(&sd->rLambFront, sd->rf); |
| 613 |
extract_diffuse(&sd->rLambBack, sd->rb); |
| 614 |
extract_diffuse(&sd->tLamb, sd->tf); |
| 615 |
/* return success */ |
| 616 |
return SDEnone; |
| 617 |
err_return: /* jump here on failure */ |
| 618 |
if (sd->rf != NULL) { |
| 619 |
SDfreeSpectralDF(sd->rf); |
| 620 |
sd->rf = NULL; |
| 621 |
} |
| 622 |
if (sd->rb != NULL) { |
| 623 |
SDfreeSpectralDF(sd->rb); |
| 624 |
sd->rb = NULL; |
| 625 |
} |
| 626 |
if (sd->tf != NULL) { |
| 627 |
SDfreeSpectralDF(sd->tf); |
| 628 |
sd->tf = NULL; |
| 629 |
} |
| 630 |
return convert_errcode(rval); |
| 631 |
} |
| 632 |
|
| 633 |
/* Get Matrix BSDF value */ |
| 634 |
static int |
| 635 |
SDgetMtxBSDF(float coef[SDmaxCh], const FVECT outVec, |
| 636 |
const FVECT inVec, const void *dist) |
| 637 |
{ |
| 638 |
const SDMat *dp = (const SDMat *)dist; |
| 639 |
int i_ndx, o_ndx; |
| 640 |
/* get angle indices */ |
| 641 |
i_ndx = mBSDF_incndx(dp, inVec); |
| 642 |
o_ndx = mBSDF_outndx(dp, outVec); |
| 643 |
/* try reciprocity if necessary */ |
| 644 |
if ((i_ndx < 0) & (o_ndx < 0)) { |
| 645 |
i_ndx = mBSDF_incndx(dp, outVec); |
| 646 |
o_ndx = mBSDF_outndx(dp, inVec); |
| 647 |
} |
| 648 |
if ((i_ndx < 0) | (o_ndx < 0)) |
| 649 |
return 0; /* nothing from this component */ |
| 650 |
coef[0] = mBSDF_value(dp, i_ndx, o_ndx); |
| 651 |
return 1; /* XXX monochrome for now */ |
| 652 |
} |
| 653 |
|
| 654 |
/* Query solid angle for vector */ |
| 655 |
static SDError |
| 656 |
SDqueryMtxProjSA(double *psa, const FVECT vec, int qflags, const void *dist) |
| 657 |
{ |
| 658 |
const SDMat *dp = (const SDMat *)dist; |
| 659 |
|
| 660 |
if (!(qflags & SDqueryInc+SDqueryOut)) |
| 661 |
return SDEargument; |
| 662 |
if (qflags & SDqueryInc) { |
| 663 |
double inc_psa = mBSDF_incohm(dp, mBSDF_incndx(dp, vec)); |
| 664 |
if (inc_psa < .0) |
| 665 |
return SDEinternal; |
| 666 |
switch (qflags & SDqueryMin+SDqueryMax) { |
| 667 |
case SDqueryMax: |
| 668 |
if (inc_psa > psa[0]) |
| 669 |
psa[0] = inc_psa; |
| 670 |
break; |
| 671 |
case SDqueryMin+SDqueryMax: |
| 672 |
if (inc_psa > psa[1]) |
| 673 |
psa[1] = inc_psa; |
| 674 |
/* fall through */ |
| 675 |
case SDqueryMin: |
| 676 |
if (inc_psa < psa[0]) |
| 677 |
psa[0] = inc_psa; |
| 678 |
break; |
| 679 |
case 0: |
| 680 |
psa[0] = inc_psa; |
| 681 |
break; |
| 682 |
} |
| 683 |
} |
| 684 |
if (qflags & SDqueryOut) { |
| 685 |
double out_psa = mBSDF_outohm(dp, mBSDF_outndx(dp, vec)); |
| 686 |
if (out_psa < .0) |
| 687 |
return SDEinternal; |
| 688 |
switch (qflags & SDqueryMin+SDqueryMax) { |
| 689 |
case SDqueryMax: |
| 690 |
if (out_psa > psa[0]) |
| 691 |
psa[0] = out_psa; |
| 692 |
break; |
| 693 |
case SDqueryMin+SDqueryMax: |
| 694 |
if (out_psa > psa[1]) |
| 695 |
psa[1] = out_psa; |
| 696 |
/* fall through */ |
| 697 |
case SDqueryMin: |
| 698 |
if (out_psa < psa[0]) |
| 699 |
psa[0] = out_psa; |
| 700 |
break; |
| 701 |
case 0: |
| 702 |
psa[(qflags&SDqueryInc)!=0] = out_psa; |
| 703 |
break; |
| 704 |
} |
| 705 |
} |
| 706 |
return SDEnone; |
| 707 |
} |
| 708 |
|
| 709 |
/* Compute new cumulative distribution from BSDF */ |
| 710 |
static int |
| 711 |
make_cdist(SDMatCDst *cd, const FVECT inVec, SDMat *dp, int rev) |
| 712 |
{ |
| 713 |
const unsigned maxval = ~0; |
| 714 |
double *cmtab, scale; |
| 715 |
int o; |
| 716 |
|
| 717 |
cmtab = (double *)malloc((cd->calen+1)*sizeof(double)); |
| 718 |
if (cmtab == NULL) |
| 719 |
return 0; |
| 720 |
cmtab[0] = .0; |
| 721 |
for (o = 0; o < cd->calen; o++) { |
| 722 |
if (rev) |
| 723 |
cmtab[o+1] = mBSDF_value(dp, o, cd->indx) * |
| 724 |
(*dp->ib_ohm)(o, dp->ib_priv); |
| 725 |
else |
| 726 |
cmtab[o+1] = mBSDF_value(dp, cd->indx, o) * |
| 727 |
(*dp->ob_ohm)(o, dp->ob_priv); |
| 728 |
cmtab[o+1] += cmtab[o]; |
| 729 |
} |
| 730 |
cd->cTotal = cmtab[cd->calen]; |
| 731 |
scale = (double)maxval / cd->cTotal; |
| 732 |
cd->carr[0] = 0; |
| 733 |
for (o = 1; o < cd->calen; o++) |
| 734 |
cd->carr[o] = scale*cmtab[o] + .5; |
| 735 |
cd->carr[cd->calen] = maxval; |
| 736 |
free(cmtab); |
| 737 |
return 1; |
| 738 |
} |
| 739 |
|
| 740 |
/* Get cumulative distribution for matrix BSDF */ |
| 741 |
static const SDCDst * |
| 742 |
SDgetMtxCDist(const FVECT inVec, SDComponent *sdc) |
| 743 |
{ |
| 744 |
SDMat *dp = (SDMat *)sdc->dist; |
| 745 |
int reverse; |
| 746 |
SDMatCDst myCD; |
| 747 |
SDMatCDst *cd, *cdlast; |
| 748 |
|
| 749 |
if (dp == NULL) |
| 750 |
return NULL; |
| 751 |
memset(&myCD, 0, sizeof(myCD)); |
| 752 |
myCD.indx = mBSDF_incndx(dp, inVec); |
| 753 |
if (myCD.indx >= 0) { |
| 754 |
myCD.ob_priv = dp->ob_priv; |
| 755 |
myCD.ob_vec = dp->ob_vec; |
| 756 |
myCD.calen = dp->nout; |
| 757 |
reverse = 0; |
| 758 |
} else { /* try reciprocity */ |
| 759 |
myCD.indx = mBSDF_outndx(dp, inVec); |
| 760 |
if (myCD.indx < 0) |
| 761 |
return NULL; |
| 762 |
myCD.ob_priv = dp->ib_priv; |
| 763 |
myCD.ob_vec = dp->ib_vec; |
| 764 |
myCD.calen = dp->ninc; |
| 765 |
reverse = 1; |
| 766 |
} |
| 767 |
cdlast = NULL; /* check for it in cache list */ |
| 768 |
for (cd = (SDMatCDst *)sdc->cdList; |
| 769 |
cd != NULL; cd = (SDMatCDst *)cd->next) { |
| 770 |
if (cd->indx == myCD.indx && (cd->calen == myCD.calen) & |
| 771 |
(cd->ob_priv == myCD.ob_priv) & |
| 772 |
(cd->ob_vec == myCD.ob_vec)) |
| 773 |
break; |
| 774 |
cdlast = cd; |
| 775 |
} |
| 776 |
if (cd == NULL) { /* need to allocate new entry */ |
| 777 |
cd = (SDMatCDst *)malloc(sizeof(SDMatCDst) + |
| 778 |
myCD.calen*sizeof(myCD.carr[0])); |
| 779 |
if (cd == NULL) |
| 780 |
return NULL; |
| 781 |
*cd = myCD; /* compute cumulative distribution */ |
| 782 |
if (!make_cdist(cd, inVec, dp, reverse)) { |
| 783 |
free(cd); |
| 784 |
return NULL; |
| 785 |
} |
| 786 |
cdlast = cd; |
| 787 |
} |
| 788 |
if (cdlast != NULL) { /* move entry to head of cache list */ |
| 789 |
cdlast->next = cd->next; |
| 790 |
cd->next = sdc->cdList; |
| 791 |
sdc->cdList = (SDCDst *)cd; |
| 792 |
} |
| 793 |
return (SDCDst *)cd; /* ready to go */ |
| 794 |
} |
| 795 |
|
| 796 |
/* Sample cumulative distribution */ |
| 797 |
static SDError |
| 798 |
SDsampMtxCDist(FVECT outVec, double randX, const SDCDst *cdp) |
| 799 |
{ |
| 800 |
const unsigned maxval = ~0; |
| 801 |
const SDMatCDst *mcd = (const SDMatCDst *)cdp; |
| 802 |
const unsigned target = randX*maxval; |
| 803 |
int i, iupper, ilower; |
| 804 |
/* binary search to find index */ |
| 805 |
ilower = 0; iupper = mcd->calen; |
| 806 |
while ((i = (iupper + ilower) >> 1) != ilower) |
| 807 |
if ((long)target >= (long)mcd->carr[i]) |
| 808 |
ilower = i; |
| 809 |
else |
| 810 |
iupper = i; |
| 811 |
/* localize random position */ |
| 812 |
randX = (randX*maxval - mcd->carr[ilower]) / |
| 813 |
(double)(mcd->carr[iupper] - mcd->carr[ilower]); |
| 814 |
/* convert index to vector */ |
| 815 |
if ((*mcd->ob_vec)(outVec, i, randX, mcd->ob_priv)) |
| 816 |
return SDEnone; |
| 817 |
strcpy(SDerrorDetail, "BSDF sampling fault"); |
| 818 |
return SDEinternal; |
| 819 |
} |
| 820 |
|
| 821 |
/* Fixed resolution BSDF methods */ |
| 822 |
SDFunc SDhandleMtx = { |
| 823 |
&SDgetMtxBSDF, |
| 824 |
&SDqueryMtxProjSA, |
| 825 |
&SDgetMtxCDist, |
| 826 |
&SDsampMtxCDist, |
| 827 |
&SDfreeMatrix, |
| 828 |
}; |
