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root/radiance/ray/src/common/bsdf.c
Revision: 2.16
Committed: Sat Feb 19 01:48:59 2011 UTC (13 years, 2 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.15: +56 -25 lines
Log Message:
Minor changes and fixes -- first working version of BSDF material

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: bsdf.c,v 2.15 2011/02/18 00:40:25 greg Exp $";
3 #endif
4 /*
5 * bsdf.c
6 *
7 * Definitions for bidirectional scattering distribution functions.
8 *
9 * Created by Greg Ward on 1/10/11.
10 *
11 */
12
13 #include <stdio.h>
14 #include <stdlib.h>
15 #include <math.h>
16 #include "ezxml.h"
17 #include "hilbert.h"
18 #include "bsdf.h"
19 #include "bsdf_m.h"
20 #include "bsdf_t.h"
21
22 /* English ASCII strings corresponding to ennumerated errors */
23 const char *SDerrorEnglish[] = {
24 "No error",
25 "Memory error",
26 "File input/output error",
27 "File format error",
28 "Illegal argument",
29 "Invalid data",
30 "Unsupported feature",
31 "Internal program error",
32 "Unknown error"
33 };
34
35 /* Additional information on last error (ASCII English) */
36 char SDerrorDetail[256];
37
38 /* Cache of loaded BSDFs */
39 struct SDCache_s *SDcacheList = NULL;
40
41 /* Retain BSDFs in cache list */
42 int SDretainSet = SDretainNone;
43
44 /* Report any error to the indicated stream (in English) */
45 SDError
46 SDreportEnglish(SDError ec, FILE *fp)
47 {
48 if (fp == NULL)
49 return ec;
50 if (!ec)
51 return SDEnone;
52 fputs(SDerrorEnglish[ec], fp);
53 if (SDerrorDetail[0]) {
54 fputs(": ", fp);
55 fputs(SDerrorDetail, fp);
56 }
57 fputc('\n', fp);
58 if (fp != stderr)
59 fflush(fp);
60 return ec;
61 }
62
63 static double
64 to_meters( /* return factor to convert given unit to meters */
65 const char *unit
66 )
67 {
68 if (unit == NULL) return(1.); /* safe assumption? */
69 if (!strcasecmp(unit, "Meter")) return(1.);
70 if (!strcasecmp(unit, "Foot")) return(.3048);
71 if (!strcasecmp(unit, "Inch")) return(.0254);
72 if (!strcasecmp(unit, "Centimeter")) return(.01);
73 if (!strcasecmp(unit, "Millimeter")) return(.001);
74 sprintf(SDerrorDetail, "Unknown dimensional unit '%s'", unit);
75 return(-1.);
76 }
77
78 /* Load geometric dimensions and description (if any) */
79 static SDError
80 SDloadGeometry(SDData *sd, ezxml_t wdb)
81 {
82 ezxml_t geom;
83 double cfact;
84 const char *fmt, *mgfstr;
85
86 if (wdb == NULL) /* no geometry section? */
87 return SDEnone;
88 sprintf(SDerrorDetail, "Negative size in \"%s\"", sd->name);
89 sd->dim[0] = sd->dim[1] = sd->dim[2] = .0;
90 if ((geom = ezxml_child(wdb, "Width")) != NULL)
91 sd->dim[0] = atof(ezxml_txt(geom)) *
92 to_meters(ezxml_attr(geom, "unit"));
93 if ((geom = ezxml_child(wdb, "Height")) != NULL)
94 sd->dim[1] = atof(ezxml_txt(geom)) *
95 to_meters(ezxml_attr(geom, "unit"));
96 if ((geom = ezxml_child(wdb, "Thickness")) != NULL)
97 sd->dim[2] = atof(ezxml_txt(geom)) *
98 to_meters(ezxml_attr(geom, "unit"));
99 if ((sd->dim[0] < .0) | (sd->dim[1] < .0) | (sd->dim[2] < .0))
100 return SDEdata;
101 if ((geom = ezxml_child(wdb, "Geometry")) == NULL ||
102 (mgfstr = ezxml_txt(geom)) == NULL)
103 return SDEnone;
104 if ((fmt = ezxml_attr(geom, "format")) != NULL &&
105 strcasecmp(fmt, "MGF")) {
106 sprintf(SDerrorDetail,
107 "Unrecognized geometry format '%s' in \"%s\"",
108 fmt, sd->name);
109 return SDEsupport;
110 }
111 cfact = to_meters(ezxml_attr(geom, "unit"));
112 sd->mgf = (char *)malloc(strlen(mgfstr)+32);
113 if (sd->mgf == NULL) {
114 strcpy(SDerrorDetail, "Out of memory in SDloadGeometry");
115 return SDEmemory;
116 }
117 if (cfact < 0.99 || cfact > 1.01)
118 sprintf(sd->mgf, "xf -s %.5f\n%s\nxf\n", cfact, mgfstr);
119 else
120 strcpy(sd->mgf, mgfstr);
121 return SDEnone;
122 }
123
124 /* Load a BSDF struct from the given file (free first and keep name) */
125 SDError
126 SDloadFile(SDData *sd, const char *fname)
127 {
128 SDError lastErr;
129 ezxml_t fl, wtl;
130
131 if ((sd == NULL) | (fname == NULL || !*fname))
132 return SDEargument;
133 /* free old data, keeping name */
134 SDfreeBSDF(sd);
135 /* parse XML file */
136 fl = ezxml_parse_file(fname);
137 if (fl == NULL) {
138 sprintf(SDerrorDetail, "Cannot open BSDF \"%s\"", fname);
139 return SDEfile;
140 }
141 if (ezxml_error(fl)[0]) {
142 sprintf(SDerrorDetail, "BSDF \"%s\" %s", fname, ezxml_error(fl));
143 ezxml_free(fl);
144 return SDEformat;
145 }
146 if (strcmp(ezxml_name(fl), "WindowElement")) {
147 sprintf(SDerrorDetail,
148 "BSDF \"%s\": top level node not 'WindowElement'",
149 sd->name);
150 ezxml_free(fl);
151 return SDEformat;
152 }
153 wtl = ezxml_child(ezxml_child(fl, "Optical"), "Layer");
154 if (wtl == NULL) {
155 sprintf(SDerrorDetail, "BSDF \"%s\": no optical layer'",
156 sd->name);
157 ezxml_free(fl);
158 return SDEformat;
159 }
160 /* load geometry if present */
161 lastErr = SDloadGeometry(sd, ezxml_child(wtl, "Material"));
162 if (lastErr)
163 return lastErr;
164 /* try loading variable resolution data */
165 lastErr = SDloadTre(sd, wtl);
166 /* check our result */
167 switch (lastErr) {
168 case SDEformat:
169 case SDEdata:
170 case SDEsupport: /* possibly we just tried the wrong format */
171 lastErr = SDloadMtx(sd, wtl);
172 break;
173 default: /* variable res. OK else serious error */
174 break;
175 }
176 /* done with XML file */
177 ezxml_free(fl);
178
179 if (lastErr) { /* was there a load error? */
180 SDfreeBSDF(sd);
181 return lastErr;
182 }
183 /* remove any insignificant components */
184 if (sd->rf != NULL && sd->rf->maxHemi <= .001) {
185 SDfreeSpectralDF(sd->rf); sd->rf = NULL;
186 }
187 if (sd->rb != NULL && sd->rb->maxHemi <= .001) {
188 SDfreeSpectralDF(sd->rb); sd->rb = NULL;
189 }
190 if (sd->tf != NULL && sd->tf->maxHemi <= .001) {
191 SDfreeSpectralDF(sd->tf); sd->tf = NULL;
192 }
193 /* return success */
194 return SDEnone;
195 }
196
197 /* Allocate new spectral distribution function */
198 SDSpectralDF *
199 SDnewSpectralDF(int nc)
200 {
201 SDSpectralDF *df;
202
203 if (nc <= 0) {
204 strcpy(SDerrorDetail, "Zero component spectral DF request");
205 return NULL;
206 }
207 df = (SDSpectralDF *)malloc(sizeof(SDSpectralDF) +
208 (nc-1)*sizeof(SDComponent));
209 if (df == NULL) {
210 sprintf(SDerrorDetail,
211 "Cannot allocate %d component spectral DF", nc);
212 return NULL;
213 }
214 df->minProjSA = .0;
215 df->maxHemi = .0;
216 df->ncomp = nc;
217 memset(df->comp, 0, nc*sizeof(SDComponent));
218 return df;
219 }
220
221 /* Free cached cumulative distributions for BSDF component */
222 void
223 SDfreeCumulativeCache(SDSpectralDF *df)
224 {
225 int n;
226 SDCDst *cdp;
227
228 if (df == NULL)
229 return;
230 for (n = df->ncomp; n-- > 0; )
231 while ((cdp = df->comp[n].cdList) != NULL) {
232 df->comp[n].cdList = cdp->next;
233 free(cdp);
234 }
235 }
236
237 /* Free a spectral distribution function */
238 void
239 SDfreeSpectralDF(SDSpectralDF *df)
240 {
241 int n;
242
243 if (df == NULL)
244 return;
245 SDfreeCumulativeCache(df);
246 for (n = df->ncomp; n-- > 0; )
247 (*df->comp[n].func->freeSC)(df->comp[n].dist);
248 free(df);
249 }
250
251 /* Shorten file path to useable BSDF name, removing suffix */
252 void
253 SDclipName(char *res, const char *fname)
254 {
255 const char *cp, *dot = NULL;
256
257 for (cp = fname; *cp; cp++)
258 if (*cp == '.')
259 dot = cp;
260 if ((dot == NULL) | (dot < fname+2))
261 dot = cp;
262 if (dot - fname >= SDnameLn)
263 fname = dot - SDnameLn + 1;
264 while (fname < dot)
265 *res++ = *fname++;
266 *res = '\0';
267 }
268
269 /* Initialize an unused BSDF struct (simply clears to zeroes) */
270 void
271 SDclearBSDF(SDData *sd)
272 {
273 if (sd != NULL)
274 memset(sd, 0, sizeof(SDData));
275 }
276
277 /* Free data associated with BSDF struct */
278 void
279 SDfreeBSDF(SDData *sd)
280 {
281 if (sd == NULL)
282 return;
283 if (sd->mgf != NULL) {
284 free(sd->mgf);
285 sd->mgf = NULL;
286 }
287 if (sd->rf != NULL) {
288 SDfreeSpectralDF(sd->rf);
289 sd->rf = NULL;
290 }
291 if (sd->rb != NULL) {
292 SDfreeSpectralDF(sd->rb);
293 sd->rb = NULL;
294 }
295 if (sd->tf != NULL) {
296 SDfreeSpectralDF(sd->tf);
297 sd->tf = NULL;
298 }
299 sd->rLambFront.cieY = .0;
300 sd->rLambFront.spec.flags = 0;
301 sd->rLambBack.cieY = .0;
302 sd->rLambBack.spec.flags = 0;
303 sd->tLamb.cieY = .0;
304 sd->tLamb.spec.flags = 0;
305 }
306
307 /* Find writeable BSDF by name, or allocate new cache entry if absent */
308 SDData *
309 SDgetCache(const char *bname)
310 {
311 struct SDCache_s *sdl;
312 char sdnam[SDnameLn];
313
314 if (bname == NULL)
315 return NULL;
316
317 SDclipName(sdnam, bname);
318 for (sdl = SDcacheList; sdl != NULL; sdl = sdl->next)
319 if (!strcmp(sdl->bsdf.name, sdnam)) {
320 sdl->refcnt++;
321 return &sdl->bsdf;
322 }
323
324 sdl = (struct SDCache_s *)calloc(1, sizeof(struct SDCache_s));
325 if (sdl == NULL)
326 return NULL;
327
328 strcpy(sdl->bsdf.name, sdnam);
329 sdl->next = SDcacheList;
330 SDcacheList = sdl;
331
332 sdl->refcnt++;
333 return &sdl->bsdf;
334 }
335
336 /* Get loaded BSDF from cache (or load and cache it on first call) */
337 /* Report any problem to stderr and return NULL on failure */
338 const SDData *
339 SDcacheFile(const char *fname)
340 {
341 SDData *sd;
342 SDError ec;
343
344 if (fname == NULL || !*fname)
345 return NULL;
346 SDerrorDetail[0] = '\0';
347 if ((sd = SDgetCache(fname)) == NULL) {
348 SDreportEnglish(SDEmemory, stderr);
349 return NULL;
350 }
351 if (!SDisLoaded(sd) && (ec = SDloadFile(sd, fname))) {
352 SDreportEnglish(ec, stderr);
353 SDfreeCache(sd);
354 return NULL;
355 }
356 return sd;
357 }
358
359 /* Free a BSDF from our cache (clear all if NULL) */
360 void
361 SDfreeCache(const SDData *sd)
362 {
363 struct SDCache_s *sdl, *sdLast = NULL;
364
365 if (sd == NULL) { /* free entire list */
366 while ((sdl = SDcacheList) != NULL) {
367 SDcacheList = sdl->next;
368 SDfreeBSDF(&sdl->bsdf);
369 free(sdl);
370 }
371 return;
372 }
373 for (sdl = SDcacheList; sdl != NULL; sdl = (sdLast=sdl)->next)
374 if (&sdl->bsdf == sd)
375 break;
376 if (sdl == NULL || --sdl->refcnt)
377 return; /* missing or still in use */
378 /* keep unreferenced data? */
379 if (SDisLoaded(sd) && SDretainSet) {
380 if (SDretainSet == SDretainAll)
381 return; /* keep everything */
382 /* else free cumulative data */
383 SDfreeCumulativeCache(sd->rf);
384 SDfreeCumulativeCache(sd->rb);
385 SDfreeCumulativeCache(sd->tf);
386 return;
387 }
388 /* remove from list and free */
389 if (sdLast == NULL)
390 SDcacheList = sdl->next;
391 else
392 sdLast->next = sdl->next;
393 SDfreeBSDF(&sdl->bsdf);
394 free(sdl);
395 }
396
397 /* Sample an individual BSDF component */
398 SDError
399 SDsampComponent(SDValue *sv, FVECT outVec, const FVECT inVec,
400 double randX, SDComponent *sdc)
401 {
402 float coef[SDmaxCh];
403 SDError ec;
404 const SDCDst *cd;
405 double d;
406 int n;
407 /* check arguments */
408 if ((sv == NULL) | (outVec == NULL) | (inVec == NULL) | (sdc == NULL))
409 return SDEargument;
410 /* get cumulative distribution */
411 cd = (*sdc->func->getCDist)(inVec, sdc);
412 if (cd == NULL)
413 return SDEmemory;
414 if (cd->cTotal <= 1e-7) { /* anything to sample? */
415 sv->spec = c_dfcolor;
416 sv->cieY = .0;
417 memset(outVec, 0, 3*sizeof(double));
418 return SDEnone;
419 }
420 sv->cieY = cd->cTotal;
421 /* compute sample direction */
422 ec = (*sdc->func->sampCDist)(outVec, randX, cd);
423 if (ec)
424 return ec;
425 /* get BSDF color */
426 n = (*sdc->func->getBSDFs)(coef, outVec, inVec, sdc->dist);
427 if (n <= 0) {
428 strcpy(SDerrorDetail, "BSDF sample value error");
429 return SDEinternal;
430 }
431 sv->spec = sdc->cspec[0];
432 d = coef[0];
433 while (--n) {
434 c_cmix(&sv->spec, d, &sv->spec, coef[n], &sdc->cspec[n]);
435 d += coef[n];
436 }
437 /* make sure everything is set */
438 c_ccvt(&sv->spec, C_CSXY+C_CSSPEC);
439 return SDEnone;
440 }
441
442 #define MS_MAXDIM 15
443
444 /* Convert 1-dimensional random variable to N-dimensional */
445 void
446 SDmultiSamp(double t[], int n, double randX)
447 {
448 unsigned nBits;
449 double scale;
450 bitmask_t ndx, coord[MS_MAXDIM];
451
452 while (n > MS_MAXDIM) /* punt for higher dimensions */
453 t[--n] = drand48();
454 nBits = (8*sizeof(bitmask_t) - 1) / n;
455 ndx = randX * (double)((bitmask_t)1 << (nBits*n));
456 /* get coordinate on Hilbert curve */
457 hilbert_i2c(n, nBits, ndx, coord);
458 /* convert back to [0,1) range */
459 scale = 1. / (double)((bitmask_t)1 << nBits);
460 while (n--)
461 t[n] = scale * ((double)coord[n] + drand48());
462 }
463
464 #undef MS_MAXDIM
465
466 /* Generate diffuse hemispherical sample */
467 static void
468 SDdiffuseSamp(FVECT outVec, int outFront, double randX)
469 {
470 /* convert to position on hemisphere */
471 SDmultiSamp(outVec, 2, randX);
472 SDsquare2disk(outVec, outVec[0], outVec[1]);
473 outVec[2] = 1. - outVec[0]*outVec[0] - outVec[1]*outVec[1];
474 if (outVec[2] > .0) /* a bit of paranoia */
475 outVec[2] = sqrt(outVec[2]);
476 if (!outFront) /* going out back? */
477 outVec[2] = -outVec[2];
478 }
479
480 /* Query projected solid angle coverage for non-diffuse BSDF direction */
481 SDError
482 SDsizeBSDF(double *projSA, const FVECT vec, int qflags, const SDData *sd)
483 {
484 SDSpectralDF *rdf;
485 SDError ec;
486 int i;
487 /* check arguments */
488 if ((projSA == NULL) | (vec == NULL) | (sd == NULL))
489 return SDEargument;
490 /* initialize extrema */
491 switch (qflags & SDqueryMin+SDqueryMax) {
492 case SDqueryMax:
493 projSA[0] = .0;
494 break;
495 case SDqueryMin+SDqueryMax:
496 projSA[1] = .0;
497 /* fall through */
498 case SDqueryMin:
499 projSA[0] = 10.;
500 break;
501 case 0:
502 return SDEargument;
503 }
504 if (vec[2] > .0) /* front surface query? */
505 rdf = sd->rf;
506 else
507 rdf = sd->rb;
508 ec = SDEdata; /* run through components */
509 for (i = (rdf==NULL) ? 0 : rdf->ncomp; i--; ) {
510 ec = (*rdf->comp[i].func->queryProjSA)(projSA, vec, qflags,
511 rdf->comp[i].dist);
512 if (ec)
513 return ec;
514 }
515 for (i = (sd->tf==NULL) ? 0 : sd->tf->ncomp; i--; ) {
516 ec = (*sd->tf->comp[i].func->queryProjSA)(projSA, vec, qflags,
517 sd->tf->comp[i].dist);
518 if (ec)
519 return ec;
520 }
521 return ec;
522 }
523
524 /* Return BSDF for the given incident and scattered ray vectors */
525 SDError
526 SDevalBSDF(SDValue *sv, const FVECT outVec, const FVECT inVec, const SDData *sd)
527 {
528 int inFront, outFront;
529 SDSpectralDF *sdf;
530 float coef[SDmaxCh];
531 int nch, i;
532 /* check arguments */
533 if ((sv == NULL) | (outVec == NULL) | (inVec == NULL) | (sd == NULL))
534 return SDEargument;
535 /* whose side are we on? */
536 inFront = (inVec[2] > .0);
537 outFront = (outVec[2] > .0);
538 /* start with diffuse portion */
539 if (inFront & outFront) {
540 *sv = sd->rLambFront;
541 sdf = sd->rf;
542 } else if (!(inFront | outFront)) {
543 *sv = sd->rLambBack;
544 sdf = sd->rb;
545 } else /* inFront ^ outFront */ {
546 *sv = sd->tLamb;
547 sdf = sd->tf;
548 }
549 sv->cieY *= 1./M_PI;
550 /* add non-diffuse components */
551 i = (sdf != NULL) ? sdf->ncomp : 0;
552 while (i-- > 0) {
553 nch = (*sdf->comp[i].func->getBSDFs)(coef, outVec, inVec,
554 sdf->comp[i].dist);
555 while (nch-- > 0) {
556 c_cmix(&sv->spec, sv->cieY, &sv->spec,
557 coef[nch], &sdf->comp[i].cspec[nch]);
558 sv->cieY += coef[nch];
559 }
560 }
561 /* make sure everything is set */
562 c_ccvt(&sv->spec, C_CSXY+C_CSSPEC);
563 return SDEnone;
564 }
565
566 /* Compute directional hemispherical scattering at this incident angle */
567 double
568 SDdirectHemi(const FVECT inVec, int sflags, const SDData *sd)
569 {
570 double hsum;
571 SDSpectralDF *rdf;
572 const SDCDst *cd;
573 int i;
574 /* check arguments */
575 if ((inVec == NULL) | (sd == NULL))
576 return .0;
577 /* gather diffuse components */
578 if (inVec[2] > .0) {
579 hsum = sd->rLambFront.cieY;
580 rdf = sd->rf;
581 } else /* !inFront */ {
582 hsum = sd->rLambBack.cieY;
583 rdf = sd->rb;
584 }
585 if ((sflags & SDsampDf+SDsampR) != SDsampDf+SDsampR)
586 hsum = .0;
587 if ((sflags & SDsampDf+SDsampT) == SDsampDf+SDsampT)
588 hsum += sd->tLamb.cieY;
589 /* gather non-diffuse components */
590 i = ((sflags & SDsampSp+SDsampR) == SDsampSp+SDsampR &&
591 rdf != NULL) ? rdf->ncomp : 0;
592 while (i-- > 0) { /* non-diffuse reflection */
593 cd = (*rdf->comp[i].func->getCDist)(inVec, &rdf->comp[i]);
594 if (cd != NULL)
595 hsum += cd->cTotal;
596 }
597 i = ((sflags & SDsampSp+SDsampT) == SDsampSp+SDsampT &&
598 sd->tf != NULL) ? sd->tf->ncomp : 0;
599 while (i-- > 0) { /* non-diffuse transmission */
600 cd = (*sd->tf->comp[i].func->getCDist)(inVec, &sd->tf->comp[i]);
601 if (cd != NULL)
602 hsum += cd->cTotal;
603 }
604 return hsum;
605 }
606
607 /* Sample BSDF direction based on the given random variable */
608 SDError
609 SDsampBSDF(SDValue *sv, FVECT outVec, const FVECT inVec,
610 double randX, int sflags, const SDData *sd)
611 {
612 SDError ec;
613 int inFront;
614 SDSpectralDF *rdf;
615 double rdiff;
616 float coef[SDmaxCh];
617 int i, j, n, nr;
618 SDComponent *sdc;
619 const SDCDst **cdarr = NULL;
620 /* check arguments */
621 if ((sv == NULL) | (outVec == NULL) | (inVec == NULL) | (sd == NULL) |
622 (randX < .0) | (randX >= 1.))
623 return SDEargument;
624 /* whose side are we on? */
625 inFront = (inVec[2] > .0);
626 /* remember diffuse portions */
627 if (inFront) {
628 *sv = sd->rLambFront;
629 rdf = sd->rf;
630 } else /* !inFront */ {
631 *sv = sd->rLambBack;
632 rdf = sd->rb;
633 }
634 if ((sflags & SDsampDf+SDsampR) != SDsampDf+SDsampR)
635 sv->cieY = .0;
636 rdiff = sv->cieY;
637 if ((sflags & SDsampDf+SDsampT) == SDsampDf+SDsampT)
638 sv->cieY += sd->tLamb.cieY;
639 /* gather non-diffuse components */
640 i = nr = ((sflags & SDsampSp+SDsampR) == SDsampSp+SDsampR &&
641 rdf != NULL) ? rdf->ncomp : 0;
642 j = ((sflags & SDsampSp+SDsampT) == SDsampSp+SDsampT &&
643 sd->tf != NULL) ? sd->tf->ncomp : 0;
644 n = i + j;
645 if (n > 0 && (cdarr = (const SDCDst **)malloc(n*sizeof(SDCDst *))) == NULL)
646 return SDEmemory;
647 while (j-- > 0) { /* non-diffuse transmission */
648 cdarr[i+j] = (*sd->tf->comp[j].func->getCDist)(inVec, &sd->tf->comp[j]);
649 if (cdarr[i+j] == NULL) {
650 free(cdarr);
651 return SDEmemory;
652 }
653 sv->cieY += cdarr[i+j]->cTotal;
654 }
655 while (i-- > 0) { /* non-diffuse reflection */
656 cdarr[i] = (*rdf->comp[i].func->getCDist)(inVec, &rdf->comp[i]);
657 if (cdarr[i] == NULL) {
658 free(cdarr);
659 return SDEmemory;
660 }
661 sv->cieY += cdarr[i]->cTotal;
662 }
663 if (sv->cieY <= 1e-7) { /* anything to sample? */
664 sv->cieY = .0;
665 memset(outVec, 0, 3*sizeof(double));
666 return SDEnone;
667 }
668 /* scale random variable */
669 randX *= sv->cieY;
670 /* diffuse reflection? */
671 if (randX < rdiff) {
672 SDdiffuseSamp(outVec, inFront, randX/rdiff);
673 goto done;
674 }
675 randX -= rdiff;
676 /* diffuse transmission? */
677 if ((sflags & SDsampDf+SDsampT) == SDsampDf+SDsampT) {
678 if (randX < sd->tLamb.cieY) {
679 sv->spec = sd->tLamb.spec;
680 SDdiffuseSamp(outVec, !inFront, randX/sd->tLamb.cieY);
681 goto done;
682 }
683 randX -= sd->tLamb.cieY;
684 }
685 /* else one of cumulative dist. */
686 for (i = 0; i < n && randX < cdarr[i]->cTotal; i++)
687 randX -= cdarr[i]->cTotal;
688 if (i >= n)
689 return SDEinternal;
690 /* compute sample direction */
691 sdc = (i < nr) ? &rdf->comp[i] : &sd->tf->comp[i-nr];
692 ec = (*sdc->func->sampCDist)(outVec, randX/cdarr[i]->cTotal, cdarr[i]);
693 if (ec)
694 return ec;
695 /* compute color */
696 j = (*sdc->func->getBSDFs)(coef, outVec, inVec, sdc->dist);
697 if (j <= 0) {
698 sprintf(SDerrorDetail, "BSDF \"%s\" sampling value error",
699 sd->name);
700 return SDEinternal;
701 }
702 sv->spec = sdc->cspec[0];
703 rdiff = coef[0];
704 while (--j) {
705 c_cmix(&sv->spec, rdiff, &sv->spec, coef[j], &sdc->cspec[j]);
706 rdiff += coef[j];
707 }
708 done:
709 if (cdarr != NULL)
710 free(cdarr);
711 /* make sure everything is set */
712 c_ccvt(&sv->spec, C_CSXY+C_CSSPEC);
713 return SDEnone;
714 }
715
716 /* Compute World->BSDF transform from surface normal and up (Y) vector */
717 SDError
718 SDcompXform(RREAL vMtx[3][3], const FVECT sNrm, const FVECT uVec)
719 {
720 if ((vMtx == NULL) | (sNrm == NULL) | (uVec == NULL))
721 return SDEargument;
722 VCOPY(vMtx[2], sNrm);
723 if (normalize(vMtx[2]) == .0)
724 return SDEargument;
725 fcross(vMtx[0], uVec, vMtx[2]);
726 if (normalize(vMtx[0]) == .0)
727 return SDEargument;
728 fcross(vMtx[1], vMtx[2], vMtx[0]);
729 return SDEnone;
730 }
731
732 /* Compute inverse transform */
733 SDError
734 SDinvXform(RREAL iMtx[3][3], RREAL vMtx[3][3])
735 {
736 RREAL mTmp[3][3];
737 double d;
738
739 if ((iMtx == NULL) | (vMtx == NULL))
740 return SDEargument;
741 /* compute determinant */
742 mTmp[0][0] = vMtx[2][2]*vMtx[1][1] - vMtx[2][1]*vMtx[1][2];
743 mTmp[0][1] = vMtx[2][1]*vMtx[0][2] - vMtx[2][2]*vMtx[0][1];
744 mTmp[0][2] = vMtx[1][2]*vMtx[0][1] - vMtx[1][1]*vMtx[0][2];
745 d = vMtx[0][0]*mTmp[0][0] + vMtx[1][0]*mTmp[0][1] + vMtx[2][0]*mTmp[0][2];
746 if (d == .0) {
747 strcpy(SDerrorDetail, "Zero determinant in matrix inversion");
748 return SDEargument;
749 }
750 d = 1./d; /* invert matrix */
751 mTmp[0][0] *= d; mTmp[0][1] *= d; mTmp[0][2] *= d;
752 mTmp[1][0] = d*(vMtx[2][0]*vMtx[1][2] - vMtx[2][2]*vMtx[1][0]);
753 mTmp[1][1] = d*(vMtx[2][2]*vMtx[0][0] - vMtx[2][0]*vMtx[0][2]);
754 mTmp[1][2] = d*(vMtx[1][0]*vMtx[0][2] - vMtx[1][2]*vMtx[0][0]);
755 mTmp[2][0] = d*(vMtx[2][1]*vMtx[1][0] - vMtx[2][0]*vMtx[1][1]);
756 mTmp[2][1] = d*(vMtx[2][0]*vMtx[0][1] - vMtx[2][1]*vMtx[0][0]);
757 mTmp[2][2] = d*(vMtx[1][1]*vMtx[0][0] - vMtx[1][0]*vMtx[0][1]);
758 memcpy(iMtx, mTmp, sizeof(mTmp));
759 return SDEnone;
760 }
761
762 /* Transform and normalize direction (column) vector */
763 SDError
764 SDmapDir(FVECT resVec, RREAL vMtx[3][3], const FVECT inpVec)
765 {
766 FVECT vTmp;
767
768 if ((resVec == NULL) | (inpVec == NULL))
769 return SDEargument;
770 if (vMtx == NULL) { /* assume they just want to normalize */
771 if (resVec != inpVec)
772 VCOPY(resVec, inpVec);
773 return (normalize(resVec) > .0) ? SDEnone : SDEargument;
774 }
775 vTmp[0] = DOT(vMtx[0], inpVec);
776 vTmp[1] = DOT(vMtx[1], inpVec);
777 vTmp[2] = DOT(vMtx[2], inpVec);
778 if (normalize(vTmp) == .0)
779 return SDEargument;
780 VCOPY(resVec, vTmp);
781 return SDEnone;
782 }
783
784 /*################################################################*/
785 /*######### DEPRECATED ROUTINES AWAITING PERMANENT REMOVAL #######*/
786
787 /*
788 * Routines for handling BSDF data
789 */
790
791 #include "standard.h"
792 #include "paths.h"
793 #include <ctype.h>
794
795 #define MAXLATS 46 /* maximum number of latitudes */
796
797 /* BSDF angle specification */
798 typedef struct {
799 char name[64]; /* basis name */
800 int nangles; /* total number of directions */
801 struct {
802 float tmin; /* starting theta */
803 short nphis; /* number of phis (0 term) */
804 } lat[MAXLATS+1]; /* latitudes */
805 } ANGLE_BASIS;
806
807 #define MAXABASES 7 /* limit on defined bases */
808
809 static ANGLE_BASIS abase_list[MAXABASES] = {
810 {
811 "LBNL/Klems Full", 145,
812 { {-5., 1},
813 {5., 8},
814 {15., 16},
815 {25., 20},
816 {35., 24},
817 {45., 24},
818 {55., 24},
819 {65., 16},
820 {75., 12},
821 {90., 0} }
822 }, {
823 "LBNL/Klems Half", 73,
824 { {-6.5, 1},
825 {6.5, 8},
826 {19.5, 12},
827 {32.5, 16},
828 {46.5, 20},
829 {61.5, 12},
830 {76.5, 4},
831 {90., 0} }
832 }, {
833 "LBNL/Klems Quarter", 41,
834 { {-9., 1},
835 {9., 8},
836 {27., 12},
837 {46., 12},
838 {66., 8},
839 {90., 0} }
840 }
841 };
842
843 static int nabases = 3; /* current number of defined bases */
844
845 #define FEQ(a,b) ((a)-(b) <= 1e-6 && (b)-(a) <= 1e-6)
846
847 static int
848 fequal(double a, double b)
849 {
850 if (b != .0)
851 a = a/b - 1.;
852 return((a <= 1e-6) & (a >= -1e-6));
853 }
854
855 /* Returns the name of the given tag */
856 #ifdef ezxml_name
857 #undef ezxml_name
858 static char *
859 ezxml_name(ezxml_t xml)
860 {
861 if (xml == NULL)
862 return(NULL);
863 return(xml->name);
864 }
865 #endif
866
867 /* Returns the given tag's character content or empty string if none */
868 #ifdef ezxml_txt
869 #undef ezxml_txt
870 static char *
871 ezxml_txt(ezxml_t xml)
872 {
873 if (xml == NULL)
874 return("");
875 return(xml->txt);
876 }
877 #endif
878
879
880 static int
881 ab_getvec( /* get vector for this angle basis index */
882 FVECT v,
883 int ndx,
884 void *p
885 )
886 {
887 ANGLE_BASIS *ab = (ANGLE_BASIS *)p;
888 int li;
889 double pol, azi, d;
890
891 if ((ndx < 0) | (ndx >= ab->nangles))
892 return(0);
893 for (li = 0; ndx >= ab->lat[li].nphis; li++)
894 ndx -= ab->lat[li].nphis;
895 pol = PI/180.*0.5*(ab->lat[li].tmin + ab->lat[li+1].tmin);
896 azi = 2.*PI*ndx/ab->lat[li].nphis;
897 v[2] = d = cos(pol);
898 d = sqrt(1. - d*d); /* sin(pol) */
899 v[0] = cos(azi)*d;
900 v[1] = sin(azi)*d;
901 return(1);
902 }
903
904
905 static int
906 ab_getndx( /* get index corresponding to the given vector */
907 FVECT v,
908 void *p
909 )
910 {
911 ANGLE_BASIS *ab = (ANGLE_BASIS *)p;
912 int li, ndx;
913 double pol, azi, d;
914
915 if ((v[2] < -1.0) | (v[2] > 1.0))
916 return(-1);
917 pol = 180.0/PI*acos(v[2]);
918 azi = 180.0/PI*atan2(v[1], v[0]);
919 if (azi < 0.0) azi += 360.0;
920 for (li = 1; ab->lat[li].tmin <= pol; li++)
921 if (!ab->lat[li].nphis)
922 return(-1);
923 --li;
924 ndx = (int)((1./360.)*azi*ab->lat[li].nphis + 0.5);
925 if (ndx >= ab->lat[li].nphis) ndx = 0;
926 while (li--)
927 ndx += ab->lat[li].nphis;
928 return(ndx);
929 }
930
931
932 static double
933 ab_getohm( /* get solid angle for this angle basis index */
934 int ndx,
935 void *p
936 )
937 {
938 ANGLE_BASIS *ab = (ANGLE_BASIS *)p;
939 int li;
940 double theta, theta1;
941
942 if ((ndx < 0) | (ndx >= ab->nangles))
943 return(0);
944 for (li = 0; ndx >= ab->lat[li].nphis; li++)
945 ndx -= ab->lat[li].nphis;
946 theta1 = PI/180. * ab->lat[li+1].tmin;
947 if (ab->lat[li].nphis == 1) { /* special case */
948 if (ab->lat[li].tmin > FTINY)
949 error(USER, "unsupported BSDF coordinate system");
950 return(2.*PI*(1. - cos(theta1)));
951 }
952 theta = PI/180. * ab->lat[li].tmin;
953 return(2.*PI*(cos(theta) - cos(theta1))/(double)ab->lat[li].nphis);
954 }
955
956
957 static int
958 ab_getvecR( /* get reverse vector for this angle basis index */
959 FVECT v,
960 int ndx,
961 void *p
962 )
963 {
964 if (!ab_getvec(v, ndx, p))
965 return(0);
966
967 v[0] = -v[0];
968 v[1] = -v[1];
969 v[2] = -v[2];
970
971 return(1);
972 }
973
974
975 static int
976 ab_getndxR( /* get index corresponding to the reverse vector */
977 FVECT v,
978 void *p
979 )
980 {
981 FVECT v2;
982
983 v2[0] = -v[0];
984 v2[1] = -v[1];
985 v2[2] = -v[2];
986
987 return ab_getndx(v2, p);
988 }
989
990
991 static void
992 load_angle_basis( /* load custom BSDF angle basis */
993 ezxml_t wab
994 )
995 {
996 char *abname = ezxml_txt(ezxml_child(wab, "AngleBasisName"));
997 ezxml_t wbb;
998 int i;
999
1000 if (!abname || !*abname)
1001 return;
1002 for (i = nabases; i--; )
1003 if (!strcasecmp(abname, abase_list[i].name))
1004 return; /* assume it's the same */
1005 if (nabases >= MAXABASES)
1006 error(INTERNAL, "too many angle bases");
1007 strcpy(abase_list[nabases].name, abname);
1008 abase_list[nabases].nangles = 0;
1009 for (i = 0, wbb = ezxml_child(wab, "AngleBasisBlock");
1010 wbb != NULL; i++, wbb = wbb->next) {
1011 if (i >= MAXLATS)
1012 error(INTERNAL, "too many latitudes in custom basis");
1013 abase_list[nabases].lat[i+1].tmin = atof(ezxml_txt(
1014 ezxml_child(ezxml_child(wbb,
1015 "ThetaBounds"), "UpperTheta")));
1016 if (!i)
1017 abase_list[nabases].lat[i].tmin =
1018 -abase_list[nabases].lat[i+1].tmin;
1019 else if (!fequal(atof(ezxml_txt(ezxml_child(ezxml_child(wbb,
1020 "ThetaBounds"), "LowerTheta"))),
1021 abase_list[nabases].lat[i].tmin))
1022 error(WARNING, "theta values disagree in custom basis");
1023 abase_list[nabases].nangles +=
1024 abase_list[nabases].lat[i].nphis =
1025 atoi(ezxml_txt(ezxml_child(wbb, "nPhis")));
1026 }
1027 abase_list[nabases++].lat[i].nphis = 0;
1028 }
1029
1030
1031 static void
1032 load_geometry( /* load geometric dimensions and description (if any) */
1033 struct BSDF_data *dp,
1034 ezxml_t wdb
1035 )
1036 {
1037 ezxml_t geom;
1038 double cfact;
1039 const char *fmt, *mgfstr;
1040
1041 dp->dim[0] = dp->dim[1] = dp->dim[2] = 0;
1042 dp->mgf = NULL;
1043 if ((geom = ezxml_child(wdb, "Width")) != NULL)
1044 dp->dim[0] = atof(ezxml_txt(geom)) *
1045 to_meters(ezxml_attr(geom, "unit"));
1046 if ((geom = ezxml_child(wdb, "Height")) != NULL)
1047 dp->dim[1] = atof(ezxml_txt(geom)) *
1048 to_meters(ezxml_attr(geom, "unit"));
1049 if ((geom = ezxml_child(wdb, "Thickness")) != NULL)
1050 dp->dim[2] = atof(ezxml_txt(geom)) *
1051 to_meters(ezxml_attr(geom, "unit"));
1052 if ((geom = ezxml_child(wdb, "Geometry")) == NULL ||
1053 (mgfstr = ezxml_txt(geom)) == NULL)
1054 return;
1055 if ((fmt = ezxml_attr(geom, "format")) != NULL &&
1056 strcasecmp(fmt, "MGF")) {
1057 sprintf(errmsg, "unrecognized geometry format '%s'", fmt);
1058 error(WARNING, errmsg);
1059 return;
1060 }
1061 cfact = to_meters(ezxml_attr(geom, "unit"));
1062 dp->mgf = (char *)malloc(strlen(mgfstr)+32);
1063 if (dp->mgf == NULL)
1064 error(SYSTEM, "out of memory in load_geometry");
1065 if (cfact < 0.99 || cfact > 1.01)
1066 sprintf(dp->mgf, "xf -s %.5f\n%s\nxf\n", cfact, mgfstr);
1067 else
1068 strcpy(dp->mgf, mgfstr);
1069 }
1070
1071
1072 static void
1073 load_bsdf_data( /* load BSDF distribution for this wavelength */
1074 struct BSDF_data *dp,
1075 ezxml_t wdb
1076 )
1077 {
1078 char *cbasis = ezxml_txt(ezxml_child(wdb,"ColumnAngleBasis"));
1079 char *rbasis = ezxml_txt(ezxml_child(wdb,"RowAngleBasis"));
1080 char *sdata;
1081 int i;
1082
1083 if ((!cbasis || !*cbasis) | (!rbasis || !*rbasis)) {
1084 error(WARNING, "missing column/row basis for BSDF");
1085 return;
1086 }
1087 for (i = nabases; i--; )
1088 if (!strcasecmp(cbasis, abase_list[i].name)) {
1089 dp->ninc = abase_list[i].nangles;
1090 dp->ib_priv = (void *)&abase_list[i];
1091 dp->ib_vec = ab_getvecR;
1092 dp->ib_ndx = ab_getndxR;
1093 dp->ib_ohm = ab_getohm;
1094 break;
1095 }
1096 if (i < 0) {
1097 sprintf(errmsg, "undefined ColumnAngleBasis '%s'", cbasis);
1098 error(WARNING, errmsg);
1099 return;
1100 }
1101 for (i = nabases; i--; )
1102 if (!strcasecmp(rbasis, abase_list[i].name)) {
1103 dp->nout = abase_list[i].nangles;
1104 dp->ob_priv = (void *)&abase_list[i];
1105 dp->ob_vec = ab_getvec;
1106 dp->ob_ndx = ab_getndx;
1107 dp->ob_ohm = ab_getohm;
1108 break;
1109 }
1110 if (i < 0) {
1111 sprintf(errmsg, "undefined RowAngleBasis '%s'", rbasis);
1112 error(WARNING, errmsg);
1113 return;
1114 }
1115 /* read BSDF data */
1116 sdata = ezxml_txt(ezxml_child(wdb,"ScatteringData"));
1117 if (!sdata || !*sdata) {
1118 error(WARNING, "missing BSDF ScatteringData");
1119 return;
1120 }
1121 dp->bsdf = (float *)malloc(sizeof(float)*dp->ninc*dp->nout);
1122 if (dp->bsdf == NULL)
1123 error(SYSTEM, "out of memory in load_bsdf_data");
1124 for (i = 0; i < dp->ninc*dp->nout; i++) {
1125 char *sdnext = fskip(sdata);
1126 if (sdnext == NULL) {
1127 error(WARNING, "bad/missing BSDF ScatteringData");
1128 free(dp->bsdf); dp->bsdf = NULL;
1129 return;
1130 }
1131 while (*sdnext && isspace(*sdnext))
1132 sdnext++;
1133 if (*sdnext == ',') sdnext++;
1134 dp->bsdf[i] = atof(sdata);
1135 sdata = sdnext;
1136 }
1137 while (isspace(*sdata))
1138 sdata++;
1139 if (*sdata) {
1140 sprintf(errmsg, "%d extra characters after BSDF ScatteringData",
1141 (int)strlen(sdata));
1142 error(WARNING, errmsg);
1143 }
1144 }
1145
1146
1147 static int
1148 check_bsdf_data( /* check that BSDF data is sane */
1149 struct BSDF_data *dp
1150 )
1151 {
1152 double *omega_iarr, *omega_oarr;
1153 double dom, contrib, hemi_total, full_total;
1154 int nneg;
1155 FVECT v;
1156 int i, o;
1157
1158 if (dp == NULL || dp->bsdf == NULL)
1159 return(0);
1160 omega_iarr = (double *)calloc(dp->ninc, sizeof(double));
1161 omega_oarr = (double *)calloc(dp->nout, sizeof(double));
1162 if ((omega_iarr == NULL) | (omega_oarr == NULL))
1163 error(SYSTEM, "out of memory in check_bsdf_data");
1164 /* incoming projected solid angles */
1165 hemi_total = .0;
1166 for (i = dp->ninc; i--; ) {
1167 dom = getBSDF_incohm(dp,i);
1168 if (dom <= .0) {
1169 error(WARNING, "zero/negative incoming solid angle");
1170 continue;
1171 }
1172 if (!getBSDF_incvec(v,dp,i) || v[2] > FTINY) {
1173 error(WARNING, "illegal incoming BSDF direction");
1174 free(omega_iarr); free(omega_oarr);
1175 return(0);
1176 }
1177 hemi_total += omega_iarr[i] = dom * -v[2];
1178 }
1179 if ((hemi_total > 1.02*PI) | (hemi_total < 0.98*PI)) {
1180 sprintf(errmsg, "incoming BSDF hemisphere off by %.1f%%",
1181 100.*(hemi_total/PI - 1.));
1182 error(WARNING, errmsg);
1183 }
1184 dom = PI / hemi_total; /* fix normalization */
1185 for (i = dp->ninc; i--; )
1186 omega_iarr[i] *= dom;
1187 /* outgoing projected solid angles */
1188 hemi_total = .0;
1189 for (o = dp->nout; o--; ) {
1190 dom = getBSDF_outohm(dp,o);
1191 if (dom <= .0) {
1192 error(WARNING, "zero/negative outgoing solid angle");
1193 continue;
1194 }
1195 if (!getBSDF_outvec(v,dp,o) || v[2] < -FTINY) {
1196 error(WARNING, "illegal outgoing BSDF direction");
1197 free(omega_iarr); free(omega_oarr);
1198 return(0);
1199 }
1200 hemi_total += omega_oarr[o] = dom * v[2];
1201 }
1202 if ((hemi_total > 1.02*PI) | (hemi_total < 0.98*PI)) {
1203 sprintf(errmsg, "outgoing BSDF hemisphere off by %.1f%%",
1204 100.*(hemi_total/PI - 1.));
1205 error(WARNING, errmsg);
1206 }
1207 dom = PI / hemi_total; /* fix normalization */
1208 for (o = dp->nout; o--; )
1209 omega_oarr[o] *= dom;
1210 nneg = 0; /* check outgoing totals */
1211 for (i = 0; i < dp->ninc; i++) {
1212 hemi_total = .0;
1213 for (o = dp->nout; o--; ) {
1214 double f = BSDF_value(dp,i,o);
1215 if (f >= .0)
1216 hemi_total += f*omega_oarr[o];
1217 else {
1218 nneg += (f < -FTINY);
1219 BSDF_value(dp,i,o) = .0f;
1220 }
1221 }
1222 if (hemi_total > 1.01) {
1223 sprintf(errmsg,
1224 "incoming BSDF direction %d passes %.1f%% of light",
1225 i, 100.*hemi_total);
1226 error(WARNING, errmsg);
1227 }
1228 }
1229 if (nneg) {
1230 sprintf(errmsg, "%d negative BSDF values (ignored)", nneg);
1231 error(WARNING, errmsg);
1232 }
1233 full_total = .0; /* reverse roles and check again */
1234 for (o = 0; o < dp->nout; o++) {
1235 hemi_total = .0;
1236 for (i = dp->ninc; i--; )
1237 hemi_total += BSDF_value(dp,i,o) * omega_iarr[i];
1238
1239 if (hemi_total > 1.01) {
1240 sprintf(errmsg,
1241 "outgoing BSDF direction %d collects %.1f%% of light",
1242 o, 100.*hemi_total);
1243 error(WARNING, errmsg);
1244 }
1245 full_total += hemi_total*omega_oarr[o];
1246 }
1247 full_total /= PI;
1248 if (full_total > 1.00001) {
1249 sprintf(errmsg, "BSDF transfers %.4f%% of light",
1250 100.*full_total);
1251 error(WARNING, errmsg);
1252 }
1253 free(omega_iarr); free(omega_oarr);
1254 return(1);
1255 }
1256
1257
1258 struct BSDF_data *
1259 load_BSDF( /* load BSDF data from file */
1260 char *fname
1261 )
1262 {
1263 char *path;
1264 ezxml_t fl, wtl, wld, wdb;
1265 struct BSDF_data *dp;
1266
1267 path = getpath(fname, getrlibpath(), R_OK);
1268 if (path == NULL) {
1269 sprintf(errmsg, "cannot find BSDF file \"%s\"", fname);
1270 error(WARNING, errmsg);
1271 return(NULL);
1272 }
1273 fl = ezxml_parse_file(path);
1274 if (fl == NULL) {
1275 sprintf(errmsg, "cannot open BSDF \"%s\"", path);
1276 error(WARNING, errmsg);
1277 return(NULL);
1278 }
1279 if (ezxml_error(fl)[0]) {
1280 sprintf(errmsg, "BSDF \"%s\" %s", path, ezxml_error(fl));
1281 error(WARNING, errmsg);
1282 ezxml_free(fl);
1283 return(NULL);
1284 }
1285 if (strcmp(ezxml_name(fl), "WindowElement")) {
1286 sprintf(errmsg,
1287 "BSDF \"%s\": top level node not 'WindowElement'",
1288 path);
1289 error(WARNING, errmsg);
1290 ezxml_free(fl);
1291 return(NULL);
1292 }
1293 wtl = ezxml_child(ezxml_child(fl, "Optical"), "Layer");
1294 if (strcasecmp(ezxml_txt(ezxml_child(ezxml_child(wtl,
1295 "DataDefinition"), "IncidentDataStructure")),
1296 "Columns")) {
1297 sprintf(errmsg,
1298 "BSDF \"%s\": unsupported IncidentDataStructure",
1299 path);
1300 error(WARNING, errmsg);
1301 ezxml_free(fl);
1302 return(NULL);
1303 }
1304 load_angle_basis(ezxml_child(ezxml_child(wtl,
1305 "DataDefinition"), "AngleBasis"));
1306 dp = (struct BSDF_data *)calloc(1, sizeof(struct BSDF_data));
1307 load_geometry(dp, ezxml_child(wtl, "Material"));
1308 for (wld = ezxml_child(wtl, "WavelengthData");
1309 wld != NULL; wld = wld->next) {
1310 if (strcasecmp(ezxml_txt(ezxml_child(wld,"Wavelength")),
1311 "Visible"))
1312 continue;
1313 for (wdb = ezxml_child(wld, "WavelengthDataBlock");
1314 wdb != NULL; wdb = wdb->next)
1315 if (!strcasecmp(ezxml_txt(ezxml_child(wdb,
1316 "WavelengthDataDirection")),
1317 "Transmission Front"))
1318 break;
1319 if (wdb != NULL) { /* load front BTDF */
1320 load_bsdf_data(dp, wdb);
1321 break; /* ignore the rest */
1322 }
1323 }
1324 ezxml_free(fl); /* done with XML file */
1325 if (!check_bsdf_data(dp)) {
1326 sprintf(errmsg, "bad/missing BTDF data in \"%s\"", path);
1327 error(WARNING, errmsg);
1328 free_BSDF(dp);
1329 dp = NULL;
1330 }
1331 return(dp);
1332 }
1333
1334
1335 void
1336 free_BSDF( /* free BSDF data structure */
1337 struct BSDF_data *b
1338 )
1339 {
1340 if (b == NULL)
1341 return;
1342 if (b->mgf != NULL)
1343 free(b->mgf);
1344 if (b->bsdf != NULL)
1345 free(b->bsdf);
1346 free(b);
1347 }
1348
1349
1350 int
1351 r_BSDF_incvec( /* compute random input vector at given location */
1352 FVECT v,
1353 struct BSDF_data *b,
1354 int i,
1355 double rv,
1356 MAT4 xm
1357 )
1358 {
1359 FVECT pert;
1360 double rad;
1361 int j;
1362
1363 if (!getBSDF_incvec(v, b, i))
1364 return(0);
1365 rad = sqrt(getBSDF_incohm(b, i) / PI);
1366 multisamp(pert, 3, rv);
1367 for (j = 0; j < 3; j++)
1368 v[j] += rad*(2.*pert[j] - 1.);
1369 if (xm != NULL)
1370 multv3(v, v, xm);
1371 return(normalize(v) != 0.0);
1372 }
1373
1374
1375 int
1376 r_BSDF_outvec( /* compute random output vector at given location */
1377 FVECT v,
1378 struct BSDF_data *b,
1379 int o,
1380 double rv,
1381 MAT4 xm
1382 )
1383 {
1384 FVECT pert;
1385 double rad;
1386 int j;
1387
1388 if (!getBSDF_outvec(v, b, o))
1389 return(0);
1390 rad = sqrt(getBSDF_outohm(b, o) / PI);
1391 multisamp(pert, 3, rv);
1392 for (j = 0; j < 3; j++)
1393 v[j] += rad*(2.*pert[j] - 1.);
1394 if (xm != NULL)
1395 multv3(v, v, xm);
1396 return(normalize(v) != 0.0);
1397 }
1398
1399
1400 static int
1401 addrot( /* compute rotation (x,y,z) => (xp,yp,zp) */
1402 char *xfarg[],
1403 FVECT xp,
1404 FVECT yp,
1405 FVECT zp
1406 )
1407 {
1408 static char bufs[3][16];
1409 int bn = 0;
1410 char **xfp = xfarg;
1411 double theta;
1412
1413 if (yp[2]*yp[2] + zp[2]*zp[2] < 2.*FTINY*FTINY) {
1414 /* Special case for X' along Z-axis */
1415 theta = -atan2(yp[0], yp[1]);
1416 *xfp++ = "-ry";
1417 *xfp++ = xp[2] < 0.0 ? "90" : "-90";
1418 *xfp++ = "-rz";
1419 sprintf(bufs[bn], "%f", theta*(180./PI));
1420 *xfp++ = bufs[bn++];
1421 return(xfp - xfarg);
1422 }
1423 theta = atan2(yp[2], zp[2]);
1424 if (!FEQ(theta,0.0)) {
1425 *xfp++ = "-rx";
1426 sprintf(bufs[bn], "%f", theta*(180./PI));
1427 *xfp++ = bufs[bn++];
1428 }
1429 theta = asin(-xp[2]);
1430 if (!FEQ(theta,0.0)) {
1431 *xfp++ = "-ry";
1432 sprintf(bufs[bn], " %f", theta*(180./PI));
1433 *xfp++ = bufs[bn++];
1434 }
1435 theta = atan2(xp[1], xp[0]);
1436 if (!FEQ(theta,0.0)) {
1437 *xfp++ = "-rz";
1438 sprintf(bufs[bn], "%f", theta*(180./PI));
1439 *xfp++ = bufs[bn++];
1440 }
1441 *xfp = NULL;
1442 return(xfp - xfarg);
1443 }
1444
1445
1446 int
1447 getBSDF_xfm( /* compute BSDF orient. -> world orient. transform */
1448 MAT4 xm,
1449 FVECT nrm,
1450 UpDir ud,
1451 char *xfbuf
1452 )
1453 {
1454 char *xfargs[7];
1455 XF myxf;
1456 FVECT updir, xdest, ydest;
1457 int i;
1458
1459 updir[0] = updir[1] = updir[2] = 0.;
1460 switch (ud) {
1461 case UDzneg:
1462 updir[2] = -1.;
1463 break;
1464 case UDyneg:
1465 updir[1] = -1.;
1466 break;
1467 case UDxneg:
1468 updir[0] = -1.;
1469 break;
1470 case UDxpos:
1471 updir[0] = 1.;
1472 break;
1473 case UDypos:
1474 updir[1] = 1.;
1475 break;
1476 case UDzpos:
1477 updir[2] = 1.;
1478 break;
1479 case UDunknown:
1480 return(0);
1481 }
1482 fcross(xdest, updir, nrm);
1483 if (normalize(xdest) == 0.0)
1484 return(0);
1485 fcross(ydest, nrm, xdest);
1486 xf(&myxf, addrot(xfargs, xdest, ydest, nrm), xfargs);
1487 copymat4(xm, myxf.xfm);
1488 if (xfbuf == NULL)
1489 return(1);
1490 /* return xf arguments as well */
1491 for (i = 0; xfargs[i] != NULL; i++) {
1492 *xfbuf++ = ' ';
1493 strcpy(xfbuf, xfargs[i]);
1494 while (*xfbuf) ++xfbuf;
1495 }
1496 return(1);
1497 }
1498
1499 /*######### END DEPRECATED ROUTINES #######*/
1500 /*################################################################*/