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root/radiance/ray/src/rt/pmapmat.c
Revision: 2.22
Committed: Mon Jan 13 17:12:19 2020 UTC (4 years, 4 months ago) by rschregle
Content type: text/plain
Branch: MAIN
CVS Tags: rad5R3
Changes since 2.21: +3 -4 lines
Log Message:
Minor comments fix

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: pmapmat.c,v 2.21 2018/12/06 20:00:35 rschregle Exp $";
3 #endif
4 /*
5 ==================================================================
6 Photon map support routines for scattering by materials.
7
8 Roland Schregle (roland.schregle@{hslu.ch, gmail.com})
9 (c) Fraunhofer Institute for Solar Energy Systems,
10 (c) Lucerne University of Applied Sciences and Arts,
11 supported by the Swiss National Science Foundation (SNSF, #147053)
12 ==================================================================
13
14 */
15
16
17
18 #include "pmapmat.h"
19 #include "pmapdata.h"
20 #include "pmaprand.h"
21 #include "otypes.h"
22 #include "data.h"
23 #include "func.h"
24 #include "bsdf.h"
25 #include <math.h>
26
27
28
29 /* Stuff ripped off from material modules */
30 #define MAXITER 10
31 #define SP_REFL 01
32 #define SP_TRAN 02
33 #define SP_PURE 04
34 #define SP_FLAT 010
35 #define SP_BADU 040
36 #define MLAMBDA 500
37 #define RINDEX 1.52
38 #define FRESNE(ci) (exp(-5.85*(ci)) - 0.00287989916)
39
40
41
42 typedef struct {
43 OBJREC *mp;
44 RAY *rp;
45 short specfl;
46 COLOR mcolor, scolor;
47 FVECT vrefl, prdir, pnorm;
48 double alpha2, rdiff, rspec, trans, tdiff, tspec, pdot;
49 } NORMDAT;
50
51 typedef struct {
52 OBJREC *mp;
53 RAY *rp;
54 short specfl;
55 COLOR mcolor, scolor;
56 FVECT vrefl, prdir, u, v, pnorm;
57 double u_alpha, v_alpha, rdiff, rspec, trans, tdiff, tspec, pdot;
58 } ANISODAT;
59
60 typedef struct {
61 OBJREC *mp;
62 RAY *pr;
63 DATARRAY *dp;
64 COLOR mcolor;
65 COLOR rdiff;
66 COLOR tdiff;
67 double rspec;
68 double trans;
69 double tspec;
70 FVECT pnorm;
71 double pdot;
72 } BRDFDAT;
73
74 typedef struct {
75 OBJREC *mp;
76 RAY *pr;
77 FVECT pnorm;
78 FVECT vray;
79 double sr_vpsa [2];
80 RREAL toloc [3][3];
81 RREAL fromloc [3][3];
82 double thick;
83 SDData *sd;
84 COLOR runsamp;
85 COLOR rdiff;
86 COLOR tunsamp;
87 COLOR tdiff;
88 } BSDFDAT;
89
90
91
92 extern const SDCDst SDemptyCD;
93
94 /* Per-material scattering function dispatch table; return value is usually
95 * zero, indicating photon termination */
96 int (*photonScatter [NUMOTYPE]) (OBJREC*, RAY*);
97
98 /* List of antimatter sensor modifier names and associated object set */
99 char *photonSensorList [MAXSET + 1] = {NULL};
100 static OBJECT photonSensorSet [MAXSET + 1] = {0};
101
102
103
104 /* ================ General support routines ================ */
105
106
107 void photonRay (const RAY *rayIn, RAY *rayOut,
108 int rayOutType, COLOR fluxAtten)
109 /* Spawn a new photon ray from a previous one; this is effectively a
110 * customised rayorigin().
111 * A SPECULAR rayOutType flags this photon as _caustic_ for subsequent hits.
112 * It is preserved for transferred rays (of type PMAP_XFER).
113 * fluxAtten specifies the RGB attenuation of the photon flux effected by
114 * the scattering material. The outgoing flux is then normalised to maintain
115 * a uniform average of 1 over RGB. If fluxAtten == NULL, the flux remains
116 * unchanged for the outgoing photon. fluxAtten is ignored for transferred
117 * rays.
118 * The ray direction is preserved for transferred rays, and undefined for
119 * scattered rays and must be subsequently set by the caller. */
120 {
121 rayorigin(rayOut, rayOutType, rayIn, NULL);
122
123 if (rayIn) {
124 /* Transfer flux */
125 copycolor(rayOut -> rcol, rayIn -> rcol);
126
127 /* Copy caustic flag & direction for transferred rays */
128 if (rayOutType == PMAP_XFER) {
129 /* rayOut -> rtype |= rayIn -> rtype & SPECULAR; */
130 rayOut -> rtype |= rayIn -> rtype;
131 VCOPY(rayOut -> rdir, rayIn -> rdir);
132 }
133 else if (fluxAtten) {
134 /* Attenuate and normalise flux for scattered rays */
135 multcolor(rayOut -> rcol, fluxAtten);
136 colorNorm(rayOut -> rcol);
137 }
138
139 /* Propagate index of emitting light source */
140 rayOut -> rsrc = rayIn -> rsrc;
141
142 /* Update maximum photon path distance */
143 rayOut -> rmax = rayIn -> rmax - rayIn -> rot;
144 }
145 }
146
147
148 static void addPhotons (const RAY *r)
149 /* Insert photon hits, where applicable */
150 {
151 if (!r -> rlvl)
152 /* Add direct photon at primary hitpoint */
153 newPhoton(directPmap, r);
154 else {
155 /* Add global or precomputed photon at indirect hitpoint */
156 newPhoton(preCompPmap ? preCompPmap : globalPmap, r);
157
158 /* Store caustic photon if specular flag set */
159 if (PMAP_CAUSTICRAY(r))
160 newPhoton(causticPmap, r);
161
162 /* Store in contribution photon map */
163 newPhoton(contribPmap, r);
164 }
165 }
166
167
168
169 void getPhotonSensors (char **sensorList)
170 /* Find antimatter geometry declared as photon sensors */
171 {
172 OBJECT i;
173 OBJREC *obj;
174 char **lp;
175
176 /* Init sensor set */
177 photonSensorSet [0] = 0;
178
179 if (!sensorList [0])
180 return;
181
182 for (i = 0; i < nobjects; i++) {
183 obj = objptr(i);
184
185 /* Insert object in sensor set if it's in the specified sensor list
186 * and of type antimatter */
187 for (lp = sensorList; *lp; lp++) {
188 if (!strcmp(obj -> oname, *lp)) {
189 if (obj -> otype != MAT_CLIP) {
190 sprintf(errmsg, "photon sensor modifier %s is not antimatter",
191 obj -> oname);
192 error(USER, errmsg);
193 }
194
195 if (photonSensorSet [0] >= AMBLLEN)
196 error(USER, "too many photon sensor modifiers");
197
198 insertelem(photonSensorSet, i);
199 }
200 }
201 }
202
203 if (!photonSensorSet [0])
204 error(USER, "no photon sensors found");
205 }
206
207
208
209 /* ================ Material specific scattering routines ================ */
210
211
212 static int isoSpecPhotonScatter (NORMDAT *nd, RAY *rayOut)
213 /* Generate direction for isotropically specularly reflected
214 or transmitted ray. Returns 1 if successful. */
215 {
216 FVECT u, v, h;
217 RAY *rayIn = nd -> rp;
218 double d, d2, sinp, cosp;
219 int niter, i = 0;
220
221 /* Set up sample coordinates */
222 getperpendicular(u, nd -> pnorm, 1);
223 fcross(v, nd -> pnorm, u);
224
225 if (nd -> specfl & SP_REFL) {
226 /* Specular reflection; make MAXITER attempts at getting a ray */
227
228 for (niter = 0; niter < MAXITER; niter++) {
229 d = 2 * PI * pmapRandom(scatterState);
230 cosp = cos(d);
231 sinp = sin(d);
232 d2 = pmapRandom(scatterState);
233 d = d2 <= FTINY ? 1 : sqrt(nd -> alpha2 * -log(d2));
234
235 for (i = 0; i < 3; i++)
236 h [i] = nd -> pnorm [i] + d * (cosp * u [i] + sinp * v [i]);
237
238 d = -2 * DOT(h, rayIn -> rdir) / (1 + d * d);
239 VSUM(rayOut -> rdir, rayIn -> rdir, h, d);
240
241 if (DOT(rayOut -> rdir, rayIn -> ron) > FTINY)
242 return 1;
243 }
244
245 return 0;
246 }
247
248 else {
249 /* Specular transmission; make MAXITER attempts at getting a ray */
250
251 for (niter = 0; niter < MAXITER; niter++) {
252 d = 2 * PI * pmapRandom(scatterState);
253 cosp = cos(d);
254 sinp = sin(d);
255 d2 = pmapRandom(scatterState);
256 d = d2 <= FTINY ? 1 : sqrt(-log(d2) * nd -> alpha2);
257
258 for (i = 0; i < 3; i++)
259 rayOut -> rdir [i] = nd -> prdir [i] +
260 d * (cosp * u [i] + sinp * v [i]);
261
262 if (DOT(rayOut -> rdir, rayIn -> ron) < -FTINY) {
263 normalize(rayOut -> rdir);
264 return 1;
265 }
266 }
267
268 return 0;
269 }
270 }
271
272
273
274 static void diffPhotonScatter (FVECT normal, RAY* rayOut)
275 /* Generate cosine-weighted direction for diffuse ray */
276 {
277 const RREAL cosThetaSqr = pmapRandom(scatterState),
278 cosTheta = sqrt(cosThetaSqr),
279 sinTheta = sqrt(1 - cosThetaSqr),
280 phi = 2 * PI * pmapRandom(scatterState),
281 du = cos(phi) * sinTheta, dv = sin(phi) * sinTheta;
282 FVECT u, v;
283 int i = 0;
284
285 /* Set up sample coordinates */
286 getperpendicular(u, normal, 1);
287 fcross(v, normal, u);
288
289 /* Convert theta & phi to cartesian */
290 for (i = 0; i < 3; i++)
291 rayOut -> rdir [i] = du * u [i] + dv * v [i] + cosTheta * normal [i];
292
293 normalize(rayOut -> rdir);
294 }
295
296
297
298 static int normalPhotonScatter (OBJREC *mat, RAY *rayIn)
299 /* Generate new photon ray for isotropic material and recurse */
300 {
301 NORMDAT nd;
302 int i, hastexture;
303 float xi, albedo, prdiff, ptdiff, prspec, ptspec;
304 double d, fresnel;
305 RAY rayOut;
306
307 if (mat -> oargs.nfargs != (mat -> otype == MAT_TRANS ? 7 : 5))
308 objerror(mat, USER, "bad number of arguments");
309
310 /* Check for back side; reorient if back is visible */
311 if (rayIn -> rod < 0)
312 if (!backvis && mat -> otype != MAT_TRANS)
313 return 0;
314 else {
315 /* Get modifiers */
316 raytexture(rayIn, mat -> omod);
317 flipsurface(rayIn);
318 }
319 else raytexture(rayIn, mat -> omod);
320
321 nd.mp = mat;
322 nd.rp = rayIn;
323
324 /* Get material color */
325 copycolor(nd.mcolor, mat -> oargs.farg);
326
327 /* Get roughness */
328 nd.specfl = 0;
329 nd.alpha2 = mat -> oargs.farg [4];
330
331 if ((nd.alpha2 *= nd.alpha2) <= FTINY)
332 nd.specfl |= SP_PURE;
333
334 if (rayIn -> ro != NULL && isflat(rayIn -> ro -> otype))
335 nd.specfl |= SP_FLAT;
336
337 /* Perturb normal */
338 if ((hastexture = (DOT(rayIn -> pert, rayIn -> pert) > sqr(FTINY)) ))
339 nd.pdot = raynormal(nd.pnorm, rayIn);
340 else {
341 VCOPY(nd.pnorm, rayIn -> ron);
342 nd.pdot = rayIn -> rod;
343 }
344
345 nd.pdot = max(nd.pdot, .001);
346
347 /* Modify material color */
348 multcolor(nd.mcolor, rayIn -> pcol);
349 nd.rspec = mat -> oargs.farg [3];
350
351 /* Approximate Fresnel term */
352 if (nd.specfl & SP_PURE && nd.rspec > FTINY) {
353 fresnel = FRESNE(rayIn -> rod);
354 nd.rspec += fresnel * (1 - nd.rspec);
355 }
356 else fresnel = 0;
357
358 /* Transmission params */
359 if (mat -> otype == MAT_TRANS) {
360 nd.trans = mat -> oargs.farg [5] * (1 - nd.rspec);
361 nd.tspec = nd.trans * mat -> oargs.farg [6];
362 nd.tdiff = nd.trans - nd.tspec;
363 }
364 else nd.tdiff = nd.tspec = nd.trans = 0;
365
366 /* Specular reflection params */
367 if (nd.rspec > FTINY) {
368 /* Specular color */
369 if (mat -> otype != MAT_METAL)
370 setcolor(nd.scolor, nd.rspec, nd.rspec, nd.rspec);
371 else if (fresnel > FTINY) {
372 d = nd.rspec * (1 - fresnel);
373 for (i = 0; i < 3; i++)
374 nd.scolor [i] = fresnel + nd.mcolor [i] * d;
375 }
376 else {
377 copycolor(nd.scolor, nd.mcolor);
378 scalecolor(nd.scolor, nd.rspec);
379 }
380 }
381 else setcolor(nd.scolor, 0, 0, 0);
382
383 /* Diffuse reflection params */
384 nd.rdiff = 1 - nd.trans - nd.rspec;
385
386 /* Set up probabilities */
387 prdiff = ptdiff = ptspec = colorAvg(nd.mcolor);
388 prdiff *= nd.rdiff;
389 ptdiff *= nd.tdiff;
390 prspec = colorAvg(nd.scolor);
391 ptspec *= nd.tspec;
392 albedo = prdiff + ptdiff + prspec + ptspec;
393
394 /* Insert direct and indirect photon hits if diffuse component */
395 if (prdiff > FTINY || ptdiff > FTINY)
396 addPhotons(rayIn);
397
398 xi = pmapRandom(rouletteState);
399
400 if (xi > albedo)
401 /* Absorbed */
402 return 0;
403
404 if (xi > (albedo -= prspec)) {
405 /* Specular reflection */
406 nd.specfl |= SP_REFL;
407
408 if (nd.specfl & SP_PURE) {
409 /* Perfect specular reflection */
410 for (i = 0; i < 3; i++) {
411 /* Reflected ray */
412 nd.vrefl [i] = rayIn -> rdir [i] + 2 * nd.pdot * nd.pnorm [i];
413 }
414
415 /* Penetration? */
416 if (hastexture && DOT(nd.vrefl, rayIn -> ron) <= FTINY)
417 for (i = 0; i < 3; i++) {
418 /* Safety measure */
419 nd.vrefl [i] = rayIn -> rdir [i] +
420 2 * rayIn -> rod * rayIn -> ron [i];
421 }
422
423 VCOPY(rayOut.rdir, nd.vrefl);
424 }
425
426 else if (!isoSpecPhotonScatter(&nd, &rayOut))
427 return 0;
428
429 photonRay(rayIn, &rayOut, PMAP_SPECREFL, nd.scolor);
430 }
431
432 else if (xi > (albedo -= ptspec)) {
433 /* Specular transmission */
434 nd.specfl |= SP_TRAN;
435
436 if (hastexture) {
437 /* Perturb */
438 for (i = 0; i < 3; i++)
439 nd.prdir [i] = rayIn -> rdir [i] - rayIn -> pert [i];
440
441 if (DOT(nd.prdir, rayIn -> ron) < -FTINY)
442 normalize(nd.prdir);
443 else VCOPY(nd.prdir, rayIn -> rdir);
444 }
445 else VCOPY(nd.prdir, rayIn -> rdir);
446
447 if ((nd.specfl & (SP_TRAN | SP_PURE)) == (SP_TRAN | SP_PURE))
448 /* Perfect specular transmission */
449 VCOPY(rayOut.rdir, nd.prdir);
450 else if (!isoSpecPhotonScatter(&nd, &rayOut))
451 return 0;
452
453 photonRay(rayIn, &rayOut, PMAP_SPECTRANS, nd.mcolor);
454 }
455
456 else if (xi > (albedo -= prdiff)) {
457 /* Diffuse reflection */
458 photonRay(rayIn, &rayOut, PMAP_DIFFREFL, nd.mcolor);
459 diffPhotonScatter(hastexture ? nd.pnorm : rayIn -> ron, &rayOut);
460 }
461
462 else {
463 /* Diffuse transmission */
464 flipsurface(rayIn);
465 photonRay(rayIn, &rayOut, PMAP_DIFFTRANS, nd.mcolor);
466
467 if (hastexture) {
468 FVECT bnorm;
469 bnorm [0] = -nd.pnorm [0];
470 bnorm [1] = -nd.pnorm [1];
471 bnorm [2] = -nd.pnorm [2];
472 diffPhotonScatter(bnorm, &rayOut);
473 }
474 else diffPhotonScatter(rayIn -> ron, &rayOut);
475 }
476
477 tracePhoton(&rayOut);
478 return 0;
479 }
480
481
482
483 static void getacoords (ANISODAT *nd)
484 /* Set up coordinate system for anisotropic sampling; cloned from aniso.c */
485 {
486 MFUNC *mf;
487 int i;
488
489 mf = getfunc(nd -> mp, 3, 0x7, 1);
490 setfunc(nd -> mp, nd -> rp);
491 errno = 0;
492
493 for (i = 0; i < 3; i++)
494 nd -> u [i] = evalue(mf -> ep [i]);
495
496 if (errno == EDOM || errno == ERANGE)
497 nd -> u [0] = nd -> u [1] = nd -> u [2] = 0.0;
498
499 if (mf -> fxp != &unitxf)
500 multv3(nd -> u, nd -> u, mf -> fxp -> xfm);
501
502 fcross(nd -> v, nd -> pnorm, nd -> u);
503
504 if (normalize(nd -> v) == 0.0) {
505 if (fabs(nd -> u_alpha - nd -> v_alpha) > 0.001)
506 objerror(nd -> mp, WARNING, "illegal orientation vector");
507 getperpendicular(nd -> u, nd -> pnorm, 1);
508 fcross(nd -> v, nd -> pnorm, nd -> u);
509 nd -> u_alpha = nd -> v_alpha =
510 sqrt(0.5 * (sqr(nd -> u_alpha) + sqr(nd -> v_alpha)));
511 }
512 else fcross(nd -> u, nd -> v, nd -> pnorm);
513 }
514
515
516
517 static int anisoSpecPhotonScatter (ANISODAT *nd, RAY *rayOut)
518 /* Generate direction for anisotropically specularly reflected
519 or transmitted ray. Returns 1 if successful. */
520 {
521 FVECT h;
522 double d, d2, sinp, cosp;
523 int niter, i;
524 RAY *rayIn = nd -> rp;
525
526 if (rayIn -> ro != NULL && isflat(rayIn -> ro -> otype))
527 nd -> specfl |= SP_FLAT;
528
529 /* set up coordinates */
530 getacoords(nd);
531
532 if (rayOut -> rtype & TRANS) {
533 /* Specular transmission */
534
535 if (DOT(rayIn -> pert, rayIn -> pert) <= sqr(FTINY))
536 VCOPY(nd -> prdir, rayIn -> rdir);
537 else {
538 /* perturb */
539 for (i = 0; i < 3; i++)
540 nd -> prdir [i] = rayIn -> rdir [i] - rayIn -> pert [i];
541
542 if (DOT(nd -> prdir, rayIn -> ron) < -FTINY)
543 normalize(nd -> prdir);
544 else VCOPY(nd -> prdir, rayIn -> rdir);
545 }
546
547 /* Make MAXITER attempts at getting a ray */
548 for (niter = 0; niter < MAXITER; niter++) {
549 d = 2 * PI * pmapRandom(scatterState);
550 cosp = cos(d) * nd -> u_alpha;
551 sinp = sin(d) * nd -> v_alpha;
552 d = sqrt(sqr(cosp) + sqr(sinp));
553 cosp /= d;
554 sinp /= d;
555 d2 = pmapRandom(scatterState);
556 d = d2 <= FTINY ? 1
557 : sqrt(-log(d2) /
558 (sqr(cosp) / sqr(nd -> u_alpha) +
559 sqr(sinp) / (nd -> v_alpha * nd -> u_alpha)));
560
561 for (i = 0; i < 3; i++)
562 rayOut -> rdir [i] = nd -> prdir [i] + d *
563 (cosp * nd -> u [i] + sinp * nd -> v [i]);
564
565 if (DOT(rayOut -> rdir, rayIn -> ron) < -FTINY) {
566 normalize(rayOut -> rdir);
567 return 1;
568 }
569 }
570
571 return 0;
572 }
573
574 else {
575 /* Specular reflection */
576
577 /* Make MAXITER attempts at getting a ray */
578 for (niter = 0; niter < MAXITER; niter++) {
579 d = 2 * PI * pmapRandom(scatterState);
580 cosp = cos(d) * nd -> u_alpha;
581 sinp = sin(d) * nd -> v_alpha;
582 d = sqrt(sqr(cosp) + sqr(sinp));
583 cosp /= d;
584 sinp /= d;
585 d2 = pmapRandom(scatterState);
586 d = d2 <= FTINY ? 1
587 : sqrt(-log(d2) /
588 (sqr(cosp) / sqr(nd -> u_alpha) +
589 sqr(sinp) / (nd->v_alpha * nd->v_alpha)));
590
591 for (i = 0; i < 3; i++)
592 h [i] = nd -> pnorm [i] +
593 d * (cosp * nd -> u [i] + sinp * nd -> v [i]);
594
595 d = -2 * DOT(h, rayIn -> rdir) / (1 + d * d);
596 VSUM(rayOut -> rdir, rayIn -> rdir, h, d);
597
598 if (DOT(rayOut -> rdir, rayIn -> ron) > FTINY)
599 return 1;
600 }
601
602 return 0;
603 }
604 }
605
606
607
608 static int anisoPhotonScatter (OBJREC *mat, RAY *rayIn)
609 /* Generate new photon ray for anisotropic material and recurse */
610 {
611 ANISODAT nd;
612 float xi, albedo, prdiff, ptdiff, prspec, ptspec;
613 RAY rayOut;
614
615 if (mat -> oargs.nfargs != (mat -> otype == MAT_TRANS2 ? 8 : 6))
616 objerror(mat, USER, "bad number of real arguments");
617
618 nd.mp = mat;
619 nd.rp = rayIn;
620
621 /* get material color */
622 copycolor(nd.mcolor, mat -> oargs.farg);
623
624 /* get roughness */
625 nd.specfl = 0;
626 nd.u_alpha = mat -> oargs.farg [4];
627 nd.v_alpha = mat -> oargs.farg [5];
628 if (nd.u_alpha < FTINY || nd.v_alpha <= FTINY)
629 objerror(mat, USER, "roughness too small");
630
631 /* check for back side; reorient if back is visible */
632 if (rayIn -> rod < 0)
633 if (!backvis && mat -> otype != MAT_TRANS2)
634 return 0;
635 else {
636 /* get modifiers */
637 raytexture(rayIn, mat -> omod);
638 flipsurface(rayIn);
639 }
640 else raytexture(rayIn, mat -> omod);
641
642 /* perturb normal */
643 nd.pdot = max(raynormal(nd.pnorm, rayIn), .001);
644
645 /* modify material color */
646 multcolor(nd.mcolor, rayIn -> pcol);
647 nd.rspec = mat -> oargs.farg [3];
648
649 /* transmission params */
650 if (mat -> otype == MAT_TRANS2) {
651 nd.trans = mat -> oargs.farg [6] * (1 - nd.rspec);
652 nd.tspec = nd.trans * mat -> oargs.farg [7];
653 nd.tdiff = nd.trans - nd.tspec;
654 if (nd.tspec > FTINY)
655 nd.specfl |= SP_TRAN;
656 }
657 else nd.tdiff = nd.tspec = nd.trans = 0;
658
659 /* specular reflection params */
660 if (nd.rspec > FTINY) {
661 nd.specfl |= SP_REFL;
662
663 /* compute specular color */
664 if (mat -> otype == MAT_METAL2)
665 copycolor(nd.scolor, nd.mcolor);
666 else setcolor(nd.scolor, 1, 1, 1);
667
668 scalecolor(nd.scolor, nd.rspec);
669 }
670 else setcolor(nd.scolor, 0, 0, 0);
671
672 /* diffuse reflection params */
673 nd.rdiff = 1 - nd.trans - nd.rspec;
674
675 /* Set up probabilities */
676 prdiff = ptdiff = ptspec = colorAvg(nd.mcolor);
677 prdiff *= nd.rdiff;
678 ptdiff *= nd.tdiff;
679 prspec = colorAvg(nd.scolor);
680 ptspec *= nd.tspec;
681 albedo = prdiff + ptdiff + prspec + ptspec;
682
683 /* Insert direct and indirect photon hits if diffuse component */
684 if (prdiff > FTINY || ptdiff > FTINY)
685 addPhotons(rayIn);
686
687 xi = pmapRandom(rouletteState);
688
689 if (xi > albedo)
690 /* Absorbed */
691 return 0;
692
693 if (xi > (albedo -= prspec))
694 /* Specular reflection */
695 if (!(nd.specfl & SP_BADU)) {
696 photonRay(rayIn, &rayOut, PMAP_SPECREFL, nd.scolor);
697
698 if (!anisoSpecPhotonScatter(&nd, &rayOut))
699 return 0;
700 }
701 else return 0;
702
703 else if (xi > (albedo -= ptspec))
704 /* Specular transmission */
705
706 if (!(nd.specfl & SP_BADU)) {
707 /* Specular transmission */
708 photonRay(rayIn, &rayOut, PMAP_SPECTRANS, nd.mcolor);
709
710 if (!anisoSpecPhotonScatter(&nd, &rayOut))
711 return 0;
712 }
713 else return 0;
714
715 else if (xi > (albedo -= prdiff)) {
716 /* Diffuse reflection */
717 photonRay(rayIn, &rayOut, PMAP_DIFFREFL, nd.mcolor);
718 diffPhotonScatter(nd.pnorm, &rayOut);
719 }
720
721 else {
722 /* Diffuse transmission */
723 FVECT bnorm;
724 flipsurface(rayIn);
725 bnorm [0] = -nd.pnorm [0];
726 bnorm [1] = -nd.pnorm [1];
727 bnorm [2] = -nd.pnorm [2];
728
729 photonRay(rayIn, &rayOut, PMAP_DIFFTRANS, nd.mcolor);
730 diffPhotonScatter(bnorm, &rayOut);
731 }
732
733 tracePhoton(&rayOut);
734 return 0;
735 }
736
737
738 static double mylog (double x)
739 /* special log for extinction coefficients; cloned from dielectric.c */
740 {
741 if (x < 1e-40)
742 return(-100.);
743
744 if (x >= 1.)
745 return(0.);
746
747 return(log(x));
748 }
749
750
751 static int dielectricPhotonScatter (OBJREC *mat, RAY *rayIn)
752 /* Generate new photon ray for dielectric material and recurse */
753 {
754 double cos1, cos2, nratio, d1, d2, refl;
755 COLOR ctrans, talb;
756 FVECT dnorm;
757 int hastexture, i;
758 RAY rayOut;
759
760 if (mat -> oargs.nfargs != (mat -> otype == MAT_DIELECTRIC ? 5 : 8))
761 objerror(mat, USER, "bad arguments");
762
763 /* get modifiers */
764 raytexture(rayIn, mat -> omod);
765
766 if ((hastexture = (DOT(rayIn -> pert, rayIn -> pert) > sqr(FTINY))))
767 /* Perturb normal */
768 cos1 = raynormal(dnorm, rayIn);
769 else {
770 VCOPY(dnorm, rayIn -> ron);
771 cos1 = rayIn -> rod;
772 }
773
774 /* index of refraction */
775 nratio = mat -> otype ==
776 MAT_DIELECTRIC ? mat->oargs.farg[3] + mat->oargs.farg[4] / MLAMBDA
777 : mat->oargs.farg[3] / mat->oargs.farg[7];
778
779 if (cos1 < 0) {
780 /* inside */
781 hastexture = -hastexture;
782 cos1 = -cos1;
783 dnorm [0] = -dnorm [0];
784 dnorm [1] = -dnorm [1];
785 dnorm [2] = -dnorm [2];
786 setcolor(rayIn -> cext,
787 -mylog(mat -> oargs.farg [0] * rayIn -> pcol [0]),
788 -mylog(mat -> oargs.farg [1] * rayIn -> pcol [1]),
789 -mylog(mat -> oargs.farg [2] * rayIn -> pcol [2]));
790 setcolor(rayIn -> albedo, 0, 0, 0);
791 rayIn -> gecc = 0;
792
793 if (mat -> otype == MAT_INTERFACE) {
794 setcolor(ctrans,
795 -mylog(mat -> oargs.farg [4] * rayIn -> pcol [0]),
796 -mylog(mat -> oargs.farg [5] * rayIn -> pcol [1]),
797 -mylog(mat -> oargs.farg [6] * rayIn -> pcol [2]));
798 setcolor(talb, 0, 0, 0);
799 }
800 else {
801 copycolor(ctrans, cextinction);
802 copycolor(talb, salbedo);
803 }
804 }
805
806 else {
807 /* outside */
808 nratio = 1.0 / nratio;
809 setcolor(ctrans,
810 -mylog(mat -> oargs.farg [0] * rayIn -> pcol [0]),
811 -mylog(mat -> oargs.farg [1] * rayIn -> pcol [1]),
812 -mylog(mat -> oargs.farg [2] * rayIn -> pcol [2]));
813 setcolor(talb, 0, 0, 0);
814
815 if (mat -> otype == MAT_INTERFACE) {
816 setcolor(rayIn -> cext,
817 -mylog(mat -> oargs.farg [4] * rayIn -> pcol [0]),
818 -mylog(mat -> oargs.farg [5] * rayIn -> pcol [1]),
819 -mylog(mat -> oargs.farg [6] * rayIn -> pcol [2]));
820 setcolor(rayIn -> albedo, 0, 0, 0);
821 rayIn -> gecc = 0;
822 }
823 }
824
825 /* compute cos theta2 */
826 d2 = 1 - sqr(nratio) * (1 - sqr(cos1));
827
828 if (d2 < FTINY) {
829 /* Total reflection */
830 refl = cos2 = 1.0;
831 }
832 else {
833 /* Refraction, compute Fresnel's equations */
834 cos2 = sqrt(d2);
835 d1 = cos1;
836 d2 = nratio * cos2;
837 d1 = (d1 - d2) / (d1 + d2);
838 refl = sqr(d1);
839 d1 = 1 / cos1;
840 d2 = nratio / cos2;
841 d1 = (d1 - d2) / (d1 + d2);
842 refl += sqr(d1);
843 refl *= 0.5;
844 }
845
846 if (pmapRandom(rouletteState) > refl) {
847 /* Refraction */
848 photonRay(rayIn, &rayOut, PMAP_REFRACT, NULL);
849 d1 = nratio * cos1 - cos2;
850
851 for (i = 0; i < 3; i++)
852 rayOut.rdir [i] = nratio * rayIn -> rdir [i] + d1 * dnorm [i];
853
854 if (hastexture && DOT(rayOut.rdir, rayIn->ron)*hastexture >= -FTINY) {
855 d1 *= hastexture;
856
857 for (i = 0; i < 3; i++)
858 rayOut.rdir [i] = nratio * rayIn -> rdir [i] +
859 d1 * rayIn -> ron [i];
860
861 normalize(rayOut.rdir);
862 }
863
864 copycolor(rayOut.cext, ctrans);
865 copycolor(rayOut.albedo, talb);
866 }
867
868 else {
869 /* Reflection */
870 photonRay(rayIn, &rayOut, PMAP_SPECREFL, NULL);
871 VSUM(rayOut.rdir, rayIn -> rdir, dnorm, 2 * cos1);
872
873 if (hastexture && DOT(rayOut.rdir, rayIn->ron) * hastexture <= FTINY)
874 for (i = 0; i < 3; i++)
875 rayOut.rdir [i] = rayIn -> rdir [i] +
876 2 * rayIn -> rod * rayIn -> ron [i];
877 }
878
879 /* Ray is modified by medium defined by cext and albedo in
880 * photonParticipate() */
881 tracePhoton(&rayOut);
882
883 return 0;
884 }
885
886
887
888 static int glassPhotonScatter (OBJREC *mat, RAY *rayIn)
889 /* Generate new photon ray for glass material and recurse */
890 {
891 float albedo, xi, ptrans;
892 COLOR mcolor, refl, trans;
893 double pdot, cos2, d, r1e, r1m, rindex = 0.0;
894 FVECT pnorm, pdir;
895 int hastexture, i;
896 RAY rayOut;
897
898 /* check arguments */
899 if (mat -> oargs.nfargs == 3)
900 rindex = RINDEX;
901 else if (mat -> oargs.nfargs == 4)
902 rindex = mat -> oargs.farg [3];
903 else objerror(mat, USER, "bad arguments");
904
905 copycolor(mcolor, mat -> oargs.farg);
906
907 /* get modifiers */
908 raytexture(rayIn, mat -> omod);
909
910 /* reorient if necessary */
911 if (rayIn -> rod < 0)
912 flipsurface(rayIn);
913 if ((hastexture = (DOT(rayIn -> pert, rayIn -> pert) > sqr(FTINY))))
914 pdot = raynormal(pnorm, rayIn);
915 else {
916 VCOPY(pnorm, rayIn -> ron);
917 pdot = rayIn -> rod;
918 }
919
920 /* Modify material color */
921 multcolor(mcolor, rayIn -> pcol);
922
923 /* angular transmission */
924 cos2 = sqrt((1 - 1 / sqr(rindex)) + sqr(pdot / rindex));
925 setcolor(mcolor, pow(mcolor [0], 1 / cos2), pow(mcolor [1], 1 / cos2),
926 pow(mcolor [2], 1 / cos2));
927
928 /* compute reflection */
929 r1e = (pdot - rindex * cos2) / (pdot + rindex * cos2);
930 r1e *= r1e;
931 r1m = (1 / pdot - rindex / cos2) / (1 / pdot + rindex / cos2);
932 r1m *= r1m;
933
934 for (i = 0; i < 3; i++) {
935 double r1ed2, r1md2, d2;
936
937 d = mcolor [i];
938 d2 = sqr(d);
939 r1ed2 = sqr(r1e) * d2;
940 r1md2 = sqr(r1m) * d2;
941
942 /* compute transmittance */
943 trans [i] = 0.5 * d *
944 (sqr(1 - r1e) / (1 - r1ed2) + sqr(1 - r1m) / (1 - r1md2));
945
946 /* compute reflectance */
947 refl [i] = 0.5 * (r1e * (1 + (1 - 2 * r1e) * d2) / (1 - r1ed2) +
948 r1m * (1 + (1 - 2 * r1m) * d2) / (1 - r1md2));
949 }
950
951 /* Set up probabilities */
952 ptrans = colorAvg(trans);
953 albedo = colorAvg(refl) + ptrans;
954 xi = pmapRandom(rouletteState);
955
956
957 if (xi > albedo)
958 /* Absorbed */
959 return 0;
960
961 if (xi > (albedo -= ptrans)) {
962 /* Transmitted */
963
964 if (hastexture) {
965 /* perturb direction */
966 VSUM(pdir, rayIn -> rdir, rayIn -> pert, 2 * (1 - rindex));
967
968 if (normalize(pdir) == 0) {
969 objerror(mat, WARNING, "bad perturbation");
970 VCOPY(pdir, rayIn -> rdir);
971 }
972 }
973 else VCOPY(pdir, rayIn -> rdir);
974
975 VCOPY(rayOut.rdir, pdir);
976 photonRay(rayIn, &rayOut, PMAP_SPECTRANS, mcolor);
977 }
978
979 else {
980 /* reflected ray */
981 VSUM(rayOut.rdir, rayIn -> rdir, pnorm, 2 * pdot);
982 photonRay(rayIn, &rayOut, PMAP_SPECREFL, mcolor);
983 }
984
985 tracePhoton(&rayOut);
986 return 0;
987 }
988
989
990
991 static int aliasPhotonScatter (OBJREC *mat, RAY *rayIn)
992 /* Transfer photon scattering to alias target */
993 {
994 OBJECT aliasObj;
995 OBJREC aliasRec, *aliasPtr;
996
997 /* Straight replacement? */
998 if (!mat -> oargs.nsargs) {
999 /* Skip void modifier! */
1000 if (mat -> omod != OVOID) {
1001 mat = objptr(mat -> omod);
1002 photonScatter [mat -> otype] (mat, rayIn);
1003 }
1004
1005 return 0;
1006 }
1007
1008 /* Else replace alias */
1009 if (mat -> oargs.nsargs != 1)
1010 objerror(mat, INTERNAL, "bad # string arguments");
1011
1012 aliasPtr = mat;
1013 aliasObj = objndx(aliasPtr);
1014
1015 /* Follow alias trail */
1016 do {
1017 aliasObj = aliasPtr -> oargs.nsargs == 1
1018 ? lastmod(aliasObj, aliasPtr -> oargs.sarg [0])
1019 : aliasPtr -> omod;
1020 if (aliasObj < 0)
1021 objerror(aliasPtr, USER, "bad reference");
1022
1023 aliasPtr = objptr(aliasObj);
1024 } while (aliasPtr -> otype == MOD_ALIAS);
1025
1026 /* Copy alias object */
1027 aliasRec = *aliasPtr;
1028
1029 /* Substitute modifier */
1030 aliasRec.omod = mat -> omod;
1031
1032 /* Replacement scattering routine */
1033 photonScatter [aliasRec.otype] (&aliasRec, rayIn);
1034
1035 /* Avoid potential memory leak? */
1036 if (aliasRec.os != aliasPtr -> os) {
1037 if (aliasPtr -> os)
1038 free_os(aliasPtr);
1039 aliasPtr -> os = aliasRec.os;
1040 }
1041
1042 return 0;
1043 }
1044
1045
1046
1047 static int clipPhotonScatter (OBJREC *mat, RAY *rayIn)
1048 /* Generate new photon ray for antimatter material and recurse */
1049 {
1050 OBJECT obj = objndx(mat), mod, cset [MAXSET + 1], *modset;
1051 int entering, inside = 0, i;
1052 const RAY *rp;
1053 RAY rayOut;
1054
1055 if ((modset = (OBJECT*)mat -> os) == NULL) {
1056 if (mat -> oargs.nsargs < 1 || mat -> oargs.nsargs > MAXSET)
1057 objerror(mat, USER, "bad # arguments");
1058
1059 modset = (OBJECT*)malloc((mat -> oargs.nsargs + 1) * sizeof(OBJECT));
1060
1061 if (modset == NULL)
1062 error(SYSTEM, "out of memory in clipPhotonScatter");
1063 modset [0] = 0;
1064
1065 for (i = 0; i < mat -> oargs.nsargs; i++) {
1066 if (!strcmp(mat -> oargs.sarg [i], VOIDID))
1067 continue;
1068
1069 if ((mod = lastmod(obj, mat -> oargs.sarg [i])) == OVOID) {
1070 sprintf(errmsg, "unknown modifier \"%s\"", mat->oargs.sarg[i]);
1071 objerror(mat, WARNING, errmsg);
1072 continue;
1073 }
1074
1075 if (inset(modset, mod)) {
1076 objerror(mat, WARNING, "duplicate modifier");
1077 continue;
1078 }
1079
1080 insertelem(modset, mod);
1081 }
1082
1083 mat -> os = (char*)modset;
1084 }
1085
1086 if (rayIn -> clipset != NULL)
1087 setcopy(cset, rayIn -> clipset);
1088 else cset [0] = 0;
1089
1090 entering = rayIn -> rod > 0;
1091
1092 /* Store photon incident from front if material defined as sensor */
1093 if (entering && inset(photonSensorSet, obj))
1094 addPhotons(rayIn);
1095
1096 for (i = modset [0]; i > 0; i--) {
1097 if (entering) {
1098 if (!inset(cset, modset [i])) {
1099 if (cset [0] >= MAXSET)
1100 error(INTERNAL, "set overflow in clipPhotonScatter");
1101 insertelem(cset, modset [i]);
1102 }
1103 }
1104 else if (inset(cset, modset [i]))
1105 deletelem(cset, modset [i]);
1106 }
1107
1108 rayIn -> newcset = cset;
1109
1110 if (strcmp(mat -> oargs.sarg [0], VOIDID)) {
1111 for (rp = rayIn; rp -> parent != NULL; rp = rp -> parent) {
1112 if ( !(rp -> rtype & RAYREFL) && rp->parent->ro != NULL &&
1113 inset(modset, rp -> parent -> ro -> omod)) {
1114
1115 if (rp -> parent -> rod > 0)
1116 inside++;
1117 else inside--;
1118 }
1119 }
1120
1121 if (inside > 0) {
1122 flipsurface(rayIn);
1123 mat = objptr(lastmod(obj, mat -> oargs.sarg [0]));
1124 photonScatter [mat -> otype] (mat, rayIn);
1125 return 0;
1126 }
1127 }
1128
1129 /* Else transfer ray */
1130 photonRay(rayIn, &rayOut, PMAP_XFER, NULL);
1131 tracePhoton(&rayOut);
1132
1133 return 0;
1134 }
1135
1136
1137
1138 static int mirrorPhotonScatter (OBJREC *mat, RAY *rayIn)
1139 /* Generate new photon ray for mirror material and recurse */
1140 {
1141 RAY rayOut;
1142 int rpure = 1, i;
1143 FVECT pnorm;
1144 double pdot;
1145 float albedo;
1146 COLOR mcolor;
1147
1148 /* check arguments */
1149 if (mat -> oargs.nfargs != 3 || mat -> oargs.nsargs > 1)
1150 objerror(mat, USER, "bad number of arguments");
1151
1152 /* back is black */
1153 if (rayIn -> rod < 0)
1154 return 0;
1155
1156 /* get modifiers */
1157 raytexture(rayIn, mat -> omod);
1158
1159 /* assign material color */
1160 copycolor(mcolor, mat -> oargs.farg);
1161 multcolor(mcolor, rayIn -> pcol);
1162
1163 /* Set up probabilities */
1164 albedo = colorAvg(mcolor);
1165
1166 if (pmapRandom(rouletteState) > albedo)
1167 /* Absorbed */
1168 return 0;
1169
1170 /* compute reflected ray */
1171 photonRay(rayIn, &rayOut, PMAP_SPECREFL, mcolor);
1172
1173 if (DOT(rayIn -> pert, rayIn -> pert) > sqr(FTINY)) {
1174 /* use textures */
1175 pdot = raynormal(pnorm, rayIn);
1176
1177 for (i = 0; i < 3; i++)
1178 rayOut.rdir [i] = rayIn -> rdir [i] + 2 * pdot * pnorm [i];
1179
1180 rpure = 0;
1181 }
1182
1183 /* Check for penetration */
1184 if (rpure || DOT(rayOut.rdir, rayIn -> ron) <= FTINY)
1185 for (i = 0; i < 3; i++)
1186 rayOut.rdir [i] = rayIn -> rdir [i] +
1187 2 * rayIn -> rod * rayIn -> ron [i];
1188
1189 tracePhoton(&rayOut);
1190 return 0;
1191 }
1192
1193
1194
1195 static int mistPhotonScatter (OBJREC *mat, RAY *rayIn)
1196 /* Generate new photon ray within mist and recurse */
1197 {
1198 COLOR mext;
1199 RREAL re, ge, be;
1200 RAY rayOut;
1201
1202 /* check arguments */
1203 if (mat -> oargs.nfargs > 7)
1204 objerror(mat, USER, "bad arguments");
1205
1206 if (mat -> oargs.nfargs > 2) {
1207 /* compute extinction */
1208 copycolor(mext, mat -> oargs.farg);
1209 /* get modifiers */
1210 raytexture(rayIn, mat -> omod);
1211 multcolor(mext, rayIn -> pcol);
1212 }
1213 else setcolor(mext, 0, 0, 0);
1214
1215 photonRay(rayIn, &rayOut, PMAP_XFER, NULL);
1216
1217 if (rayIn -> rod > 0) {
1218 /* entering ray */
1219 addcolor(rayOut.cext, mext);
1220
1221 if (mat -> oargs.nfargs > 5)
1222 copycolor(rayOut.albedo, mat -> oargs.farg + 3);
1223 if (mat -> oargs.nfargs > 6)
1224 rayOut.gecc = mat -> oargs.farg [6];
1225 }
1226
1227 else {
1228 /* leaving ray */
1229 re = max(rayIn -> cext [0] - mext [0], cextinction [0]);
1230 ge = max(rayIn -> cext [1] - mext [1], cextinction [1]);
1231 be = max(rayIn -> cext [2] - mext [2], cextinction [2]);
1232 setcolor(rayOut.cext, re, ge, be);
1233
1234 if (mat -> oargs.nfargs > 5)
1235 copycolor(rayOut.albedo, salbedo);
1236 if (mat -> oargs.nfargs > 6)
1237 rayOut.gecc = seccg;
1238 }
1239
1240 tracePhoton(&rayOut);
1241
1242 return 0;
1243 }
1244
1245
1246
1247 static int mx_dataPhotonScatter (OBJREC *mat, RAY *rayIn)
1248 /* Pass photon on to materials selected by mixture data */
1249 {
1250 OBJECT obj;
1251 double coef, pt [MAXDIM];
1252 DATARRAY *dp;
1253 OBJECT mod [2];
1254 MFUNC *mf;
1255 int i;
1256
1257 if (mat -> oargs.nsargs < 6)
1258 objerror(mat, USER, "bad # arguments");
1259
1260 obj = objndx(mat);
1261
1262 for (i = 0; i < 2; i++)
1263 if (!strcmp(mat -> oargs.sarg [i], VOIDID))
1264 mod [i] = OVOID;
1265 else if ((mod [i] = lastmod(obj, mat -> oargs.sarg [i])) == OVOID) {
1266 sprintf(errmsg, "undefined modifier \"%s\"", mat->oargs.sarg[i]);
1267 objerror(mat, USER, errmsg);
1268 }
1269
1270 dp = getdata(mat -> oargs.sarg [3]);
1271 i = (1 << dp -> nd) - 1;
1272 mf = getfunc(mat, 4, i << 5, 0);
1273 setfunc(mat, rayIn);
1274 errno = 0;
1275
1276 for (i = 0; i < dp -> nd; i++) {
1277 pt [i] = evalue(mf -> ep [i]);
1278
1279 if (errno) {
1280 objerror(mat, WARNING, "compute error");
1281 return 0;
1282 }
1283 }
1284
1285 coef = datavalue(dp, pt);
1286 errno = 0;
1287 coef = funvalue(mat -> oargs.sarg [2], 1, &coef);
1288
1289 if (errno)
1290 objerror(mat, WARNING, "compute error");
1291 else {
1292 OBJECT mxMod = mod [pmapRandom(rouletteState) < coef ? 0 : 1];
1293
1294 if (mxMod != OVOID) {
1295 mat = objptr(mxMod);
1296 photonScatter [mat -> otype] (mat, rayIn);
1297 }
1298 else {
1299 /* Transfer ray if no modifier */
1300 RAY rayOut;
1301
1302 photonRay(rayIn, &rayOut, PMAP_XFER, NULL);
1303 tracePhoton(&rayOut);
1304 }
1305 }
1306
1307 return 0;
1308 }
1309
1310
1311
1312 static int mx_pdataPhotonScatter (OBJREC *mat, RAY *rayIn)
1313 /* Pass photon on to materials selected by mixture picture */
1314 {
1315 OBJECT obj;
1316 double col [3], coef, pt [MAXDIM];
1317 DATARRAY *dp;
1318 OBJECT mod [2];
1319 MFUNC *mf;
1320 int i;
1321
1322 if (mat -> oargs.nsargs < 7)
1323 objerror(mat, USER, "bad # arguments");
1324
1325 obj = objndx(mat);
1326
1327 for (i = 0; i < 2; i++)
1328 if (!strcmp(mat -> oargs.sarg [i], VOIDID))
1329 mod [i] = OVOID;
1330 else if ((mod [i] = lastmod(obj, mat -> oargs.sarg [i])) == OVOID) {
1331 sprintf(errmsg, "undefined modifier \"%s\"", mat->oargs.sarg[i]);
1332 objerror(mat, USER, errmsg);
1333 }
1334
1335 dp = getpict(mat -> oargs.sarg [3]);
1336 mf = getfunc(mat, 4, 0x3 << 5, 0);
1337 setfunc(mat, rayIn);
1338 errno = 0;
1339 pt [1] = evalue(mf -> ep [0]);
1340 pt [0] = evalue(mf -> ep [1]);
1341
1342 if (errno) {
1343 objerror(mat, WARNING, "compute error");
1344 return 0;
1345 }
1346
1347 for (i = 0; i < 3; i++)
1348 col [i] = datavalue(dp + i, pt);
1349
1350 errno = 0;
1351 coef = funvalue(mat -> oargs.sarg [2], 3, col);
1352
1353 if (errno)
1354 objerror(mat, WARNING, "compute error");
1355 else {
1356 OBJECT mxMod = mod [pmapRandom(rouletteState) < coef ? 0 : 1];
1357
1358 if (mxMod != OVOID) {
1359 mat = objptr(mxMod);
1360 photonScatter [mat -> otype] (mat, rayIn);
1361 }
1362 else {
1363 /* Transfer ray if no modifier */
1364 RAY rayOut;
1365
1366 photonRay(rayIn, &rayOut, PMAP_XFER, NULL);
1367 tracePhoton(&rayOut);
1368 }
1369 }
1370
1371 return 0;
1372 }
1373
1374
1375
1376 static int mx_funcPhotonScatter (OBJREC *mat, RAY *rayIn)
1377 /* Pass photon on to materials selected by mixture function */
1378 {
1379 OBJECT obj, mod [2];
1380 int i;
1381 double coef;
1382 MFUNC *mf;
1383
1384 if (mat -> oargs.nsargs < 4)
1385 objerror(mat, USER, "bad # arguments");
1386
1387 obj = objndx(mat);
1388
1389 for (i = 0; i < 2; i++)
1390 if (!strcmp(mat -> oargs.sarg [i], VOIDID))
1391 mod [i] = OVOID;
1392 else if ((mod [i] = lastmod(obj, mat -> oargs.sarg [i])) == OVOID) {
1393 sprintf(errmsg, "undefined modifier \"%s\"", mat->oargs.sarg[i]);
1394 objerror(mat, USER, errmsg);
1395 }
1396
1397 mf = getfunc(mat, 3, 0x4, 0);
1398 setfunc(mat, rayIn);
1399 errno = 0;
1400
1401 /* bound coefficient */
1402 coef = min(1, max(0, evalue(mf -> ep [0])));
1403
1404 if (errno)
1405 objerror(mat, WARNING, "compute error");
1406 else {
1407 OBJECT mxMod = mod [pmapRandom(rouletteState) < coef ? 0 : 1];
1408
1409 if (mxMod != OVOID) {
1410 mat = objptr(mxMod);
1411 photonScatter [mat -> otype] (mat, rayIn);
1412 }
1413 else {
1414 /* Transfer ray if no modifier */
1415 RAY rayOut;
1416
1417 photonRay(rayIn, &rayOut, PMAP_XFER, NULL);
1418 tracePhoton(&rayOut);
1419 }
1420 }
1421
1422 return 0;
1423 }
1424
1425
1426
1427 static int pattexPhotonScatter (OBJREC *mat, RAY *rayIn)
1428 /* Generate new photon ray for pattern or texture modifier and recurse.
1429 This code is brought to you by Henkel! :^) */
1430 {
1431 RAY rayOut;
1432
1433 /* Get pattern */
1434 ofun [mat -> otype].funp(mat, rayIn);
1435 if (mat -> omod != OVOID) {
1436 /* Scatter using modifier (if any) */
1437 mat = objptr(mat -> omod);
1438 photonScatter [mat -> otype] (mat, rayIn);
1439 }
1440 else {
1441 /* Transfer ray if no modifier */
1442 photonRay(rayIn, &rayOut, PMAP_XFER, NULL);
1443 tracePhoton(&rayOut);
1444 }
1445
1446 return 0;
1447 }
1448
1449
1450
1451 static int setbrdfunc(BRDFDAT *bd)
1452 /* Set up brdf function and variables; ripped off from m_brdf.c */
1453 {
1454 FVECT v;
1455
1456 if (setfunc(bd -> mp, bd -> pr) == 0)
1457 return 0;
1458
1459 /* (Re)Assign func variables */
1460 multv3(v, bd -> pnorm, funcxf.xfm);
1461 varset("NxP", '=', v [0] / funcxf.sca);
1462 varset("NyP", '=', v [1] / funcxf.sca);
1463 varset("NzP", '=', v [2] / funcxf.sca);
1464 varset("RdotP", '=',
1465 bd -> pdot <= -1. ? -1. : bd -> pdot >= 1. ? 1. : bd -> pdot);
1466 varset("CrP", '=', colval(bd -> mcolor, RED));
1467 varset("CgP", '=', colval(bd -> mcolor, GRN));
1468 varset("CbP", '=', colval(bd -> mcolor, BLU));
1469
1470 return 1;
1471 }
1472
1473
1474
1475 static int brdfPhotonScatter (OBJREC *mat, RAY *rayIn)
1476 /* Generate new photon ray for BRTDfunc material and recurse. Only ideal
1477 reflection and transmission are sampled for the specular componentent. */
1478 {
1479 int hitfront = 1, hastexture, i;
1480 BRDFDAT nd;
1481 RAY rayOut;
1482 COLOR rspecCol, tspecCol;
1483 double prDiff, ptDiff, prSpec, ptSpec, albedo, xi;
1484 MFUNC *mf;
1485 FVECT bnorm;
1486
1487 /* Check argz */
1488 if (mat -> oargs.nsargs < 10 || mat -> oargs.nfargs < 9)
1489 objerror(mat, USER, "bad # arguments");
1490
1491 nd.mp = mat;
1492 nd.pr = rayIn;
1493 /* Dummiez */
1494 nd.rspec = nd.tspec = 1.0;
1495 nd.trans = 0.5;
1496
1497 /* Diffuz reflektanz */
1498 if (rayIn -> rod > 0.0)
1499 setcolor(nd.rdiff, mat -> oargs.farg[0], mat -> oargs.farg [1],
1500 mat -> oargs.farg [2]);
1501 else
1502 setcolor(nd.rdiff, mat-> oargs.farg [3], mat -> oargs.farg [4],
1503 mat -> oargs.farg [5]);
1504 /* Diffuz tranzmittanz */
1505 setcolor(nd.tdiff, mat -> oargs.farg [6], mat -> oargs.farg [7],
1506 mat -> oargs.farg [8]);
1507
1508 /* Get modz */
1509 raytexture(rayIn, mat -> omod);
1510 hastexture = (DOT(rayIn -> pert, rayIn -> pert) > sqr(FTINY));
1511 if (hastexture) {
1512 /* Perturb normal */
1513 nd.pdot = raynormal(nd.pnorm, rayIn);
1514 }
1515 else {
1516 VCOPY(nd.pnorm, rayIn -> ron);
1517 nd.pdot = rayIn -> rod;
1518 }
1519
1520 if (rayIn -> rod < 0.0) {
1521 /* Orient perturbed valuz */
1522 nd.pdot = -nd.pdot;
1523 for (i = 0; i < 3; i++) {
1524 nd.pnorm [i] = -nd.pnorm [i];
1525 rayIn -> pert [i] = -rayIn -> pert [i];
1526 }
1527
1528 hitfront = 0;
1529 }
1530
1531 /* Get pattern kolour, modify diffuz valuz */
1532 copycolor(nd.mcolor, rayIn -> pcol);
1533 multcolor(nd.rdiff, nd.mcolor);
1534 multcolor(nd.tdiff, nd.mcolor);
1535
1536 /* Load cal file, evaluate spekula refl/tranz varz */
1537 nd.dp = NULL;
1538 mf = getfunc(mat, 9, 0x3f, 0);
1539 setbrdfunc(&nd);
1540 errno = 0;
1541 setcolor(rspecCol,
1542 evalue(mf->ep[0]), evalue(mf->ep[1]), evalue(mf->ep[2]));
1543 setcolor(tspecCol,
1544 evalue(mf->ep[3]), evalue(mf->ep[4]), evalue(mf->ep[5]));
1545 if (errno == EDOM || errno == ERANGE)
1546 objerror(mat, WARNING, "compute error");
1547 else {
1548 /* Set up probz */
1549 prDiff = colorAvg(nd.rdiff);
1550 ptDiff = colorAvg(nd.tdiff);
1551 prSpec = colorAvg(rspecCol);
1552 ptSpec = colorAvg(tspecCol);
1553 albedo = prDiff + ptDiff + prSpec + ptSpec;
1554 }
1555
1556 /* Insert direct and indirect photon hitz if diffuz komponent */
1557 if (prDiff > FTINY || ptDiff > FTINY)
1558 addPhotons(rayIn);
1559
1560 /* Stochastically sample absorption or scattering evenz */
1561 if ((xi = pmapRandom(rouletteState)) > albedo)
1562 /* Absorbed */
1563 return 0;
1564
1565 if (xi > (albedo -= prSpec)) {
1566 /* Ideal spekula reflekzion */
1567 photonRay(rayIn, &rayOut, PMAP_SPECREFL, rspecCol);
1568 VSUM(rayOut.rdir, rayIn -> rdir, nd.pnorm, 2 * nd.pdot);
1569 checknorm(rayOut.rdir);
1570 }
1571 else if (xi > (albedo -= ptSpec)) {
1572 /* Ideal spekula tranzmission */
1573 photonRay(rayIn, &rayOut, PMAP_SPECTRANS, tspecCol);
1574 if (hastexture) {
1575 /* Perturb direkzion */
1576 VSUB(rayOut.rdir, rayIn -> rdir, rayIn -> pert);
1577 if (normalize(rayOut.rdir) == 0.0) {
1578 objerror(mat, WARNING, "illegal perturbation");
1579 VCOPY(rayOut.rdir, rayIn -> rdir);
1580 }
1581 else VCOPY(rayOut.rdir, rayIn -> rdir);
1582 }
1583 }
1584 else if (xi > (albedo -= prDiff)) {
1585 /* Diffuz reflekzion */
1586 if (!hitfront)
1587 flipsurface(rayIn);
1588 photonRay(rayIn, &rayOut, PMAP_DIFFREFL, nd.mcolor);
1589 diffPhotonScatter(nd.pnorm, &rayOut);
1590 }
1591 else {
1592 /* Diffuz tranzmission */
1593 if (hitfront)
1594 flipsurface(rayIn);
1595 photonRay(rayIn, &rayOut, PMAP_DIFFTRANS, nd.mcolor);
1596 bnorm [0] = -nd.pnorm [0];
1597 bnorm [1] = -nd.pnorm [1];
1598 bnorm [2] = -nd.pnorm [2];
1599 diffPhotonScatter(bnorm, &rayOut);
1600 }
1601
1602 tracePhoton(&rayOut);
1603 return 0;
1604 }
1605
1606
1607
1608 int brdf2PhotonScatter (OBJREC *mat, RAY *rayIn)
1609 /* Generate new photon ray for procedural or data driven BRDF material and
1610 recurse. Only diffuse reflection and transmission are sampled. */
1611 {
1612 BRDFDAT nd;
1613 RAY rayOut;
1614 double dtmp, prDiff, ptDiff, albedo, xi;
1615 MFUNC *mf;
1616 FVECT bnorm;
1617
1618 /* Check argz */
1619 if (mat -> oargs.nsargs < (hasdata(mat -> otype) ? 4 : 2) ||
1620 mat -> oargs.nfargs < (mat -> otype == MAT_TFUNC ||
1621 mat -> otype == MAT_TDATA ? 6 : 4))
1622 objerror(mat, USER, "bad # arguments");
1623
1624 if (rayIn -> rod < 0.0) {
1625 /* Hit backside; reorient if visible, else transfer photon */
1626 if (!backvis) {
1627 photonRay(rayIn, &rayOut, PMAP_XFER, NULL);
1628 tracePhoton(&rayOut);
1629 return 0;
1630 }
1631
1632 raytexture(rayIn, mat -> omod);
1633 flipsurface(rayIn);
1634 }
1635 else raytexture(rayIn, mat -> omod);
1636
1637 nd.mp = mat;
1638 nd.pr = rayIn;
1639
1640 /* Material kolour */
1641 setcolor(nd.mcolor, mat -> oargs.farg [0], mat -> oargs.farg [1],
1642 mat -> oargs.farg [2]);
1643 /* Spekula komponent */
1644 nd.rspec = mat -> oargs.farg [3];
1645
1646 /* Tranzmittanz */
1647 if (mat -> otype == MAT_TFUNC || mat -> otype == MAT_TDATA) {
1648 nd.trans = mat -> oargs.farg [4] * (1.0 - nd.rspec);
1649 nd.tspec = nd.trans * mat -> oargs.farg [5];
1650 dtmp = nd.trans - nd.tspec;
1651 setcolor(nd.tdiff, dtmp, dtmp, dtmp);
1652 }
1653 else {
1654 nd.tspec = nd.trans = 0.0;
1655 setcolor(nd.tdiff, 0.0, 0.0, 0.0);
1656 }
1657
1658 /* Reflektanz */
1659 dtmp = 1.0 - nd.trans - nd.rspec;
1660 setcolor(nd.rdiff, dtmp, dtmp, dtmp);
1661 /* Perturb normal */
1662 nd.pdot = raynormal(nd.pnorm, rayIn);
1663 /* Modify material kolour */
1664 multcolor(nd.mcolor, rayIn -> pcol);
1665 multcolor(nd.rdiff, nd.mcolor);
1666 multcolor(nd.tdiff, nd.mcolor);
1667
1668 /* Load auxiliary filez */
1669 if (hasdata(mat -> otype)) {
1670 nd.dp = getdata(mat -> oargs.sarg [1]);
1671 getfunc(mat, 2, 0, 0);
1672 }
1673 else {
1674 nd.dp = NULL;
1675 getfunc(mat, 1, 0, 0);
1676 }
1677
1678 /* Set up probz */
1679 prDiff = colorAvg(nd.rdiff);
1680 ptDiff = colorAvg(nd.tdiff);
1681 albedo = prDiff + ptDiff;
1682
1683 /* Insert direct and indirect photon hitz if diffuz komponent */
1684 if (prDiff > FTINY || ptDiff > FTINY)
1685 addPhotons(rayIn);
1686
1687 /* Stochastically sample absorption or scattering evenz */
1688 if ((xi = pmapRandom(rouletteState)) > albedo)
1689 /* Absorbed */
1690 return 0;
1691
1692 if (xi > (albedo -= prDiff)) {
1693 /* Diffuz reflekzion */
1694 photonRay(rayIn, &rayOut, PMAP_DIFFREFL, nd.rdiff);
1695 diffPhotonScatter(nd.pnorm, &rayOut);
1696 }
1697 else {
1698 /* Diffuz tranzmission */
1699 flipsurface(rayIn);
1700 photonRay(rayIn, &rayOut, PMAP_DIFFTRANS, nd.tdiff);
1701 bnorm [0] = -nd.pnorm [0];
1702 bnorm [1] = -nd.pnorm [1];
1703 bnorm [2] = -nd.pnorm [2];
1704 diffPhotonScatter(bnorm, &rayOut);
1705 }
1706
1707 tracePhoton(&rayOut);
1708 return 0;
1709 }
1710
1711
1712
1713 /*
1714 ==================================================================
1715 The following code is
1716 (c) Lucerne University of Applied Sciences and Arts,
1717 supported by the Swiss National Science Foundation (SNSF, #147053)
1718 ==================================================================
1719 */
1720
1721 static int bsdfPhotonScatter (OBJREC *mat, RAY *rayIn)
1722 /* Generate new photon ray for BSDF modifier and recurse. */
1723 {
1724 int hasthick = (mat->otype == MAT_BSDF);
1725 int hitFront;
1726 SDError err;
1727 SDValue bsdfVal;
1728 FVECT upvec;
1729 MFUNC *mf;
1730 BSDFDAT nd;
1731 RAY rayOut;
1732 COLOR bsdfRGB;
1733 int transmitted;
1734 double prDiff, ptDiff, prDiffSD, ptDiffSD, prSpecSD, ptSpecSD,
1735 albedo, xi;
1736 const double patAlb = bright(rayIn -> pcol);
1737
1738 /* Following code adapted from m_bsdf() */
1739 /* Check arguments */
1740 if (mat -> oargs.nsargs < hasthick+5 || mat -> oargs.nfargs > 9 ||
1741 mat -> oargs.nfargs % 3)
1742 objerror(mat, USER, "bad # arguments");
1743
1744 hitFront = (rayIn -> rod > 0);
1745
1746 /* Load cal file */
1747 mf = hasthick ? getfunc(mat, 5, 0x1d, 1) : getfunc(mat, 4, 0xe, 1);
1748
1749 /* Get thickness */
1750 nd.thick = 0;
1751 if (hasthick) {
1752 nd.thick = evalue(mf -> ep [0]);
1753 if ((-FTINY <= nd.thick) & (nd.thick <= FTINY))
1754 nd.thick = .0;
1755 }
1756
1757 /* Get BSDF data */
1758 nd.sd = loadBSDF(mat -> oargs.sarg [hasthick]);
1759
1760 /* Extra diffuse reflectance from material def */
1761 if (hitFront) {
1762 if (mat -> oargs.nfargs < 3)
1763 setcolor(nd.rdiff, .0, .0, .0);
1764 else setcolor(nd.rdiff, mat -> oargs.farg [0], mat -> oargs.farg [1],
1765 mat -> oargs.farg [2]);
1766 }
1767 else if (mat -> oargs.nfargs < 6) {
1768 /* Check for absorbing backside */
1769 if (!backvis && !nd.sd -> rb && !nd.sd -> tf) {
1770 SDfreeCache(nd.sd);
1771 return 0;
1772 }
1773
1774 setcolor(nd.rdiff, .0, .0, .0);
1775 }
1776 else setcolor(nd.rdiff, mat -> oargs.farg [3], mat -> oargs.farg [4],
1777 mat -> oargs.farg [5]);
1778
1779 /* Extra diffuse transmittance from material def */
1780 if (mat -> oargs.nfargs < 9)
1781 setcolor(nd.tdiff, .0, .0, .0);
1782 else setcolor(nd.tdiff, mat -> oargs.farg [6], mat -> oargs.farg [7],
1783 mat -> oargs.farg [8]);
1784
1785 nd.mp = mat;
1786 nd.pr = rayIn;
1787
1788 /* Get modifiers */
1789 raytexture(rayIn, mat -> omod);
1790
1791 /* Modify diffuse values */
1792 multcolor(nd.rdiff, rayIn -> pcol);
1793 multcolor(nd.tdiff, rayIn -> pcol);
1794
1795 /* Get up vector & xform to world coords */
1796 upvec [0] = evalue(mf -> ep [hasthick+0]);
1797 upvec [1] = evalue(mf -> ep [hasthick+1]);
1798 upvec [2] = evalue(mf -> ep [hasthick+2]);
1799
1800 if (mf -> fxp != &unitxf) {
1801 multv3(upvec, upvec, mf -> fxp -> xfm);
1802 nd.thick *= mf -> fxp -> sca;
1803 }
1804
1805 if (rayIn -> rox) {
1806 multv3(upvec, upvec, rayIn -> rox -> f.xfm);
1807 nd.thick *= rayIn -> rox -> f.sca;
1808 }
1809
1810 /* Perturb normal */
1811 raynormal(nd.pnorm, rayIn);
1812
1813 /* Xform incident dir to local BSDF coords */
1814 err = SDcompXform(nd.toloc, nd.pnorm, upvec);
1815
1816 if (!err) {
1817 nd.vray [0] = -rayIn -> rdir [0];
1818 nd.vray [1] = -rayIn -> rdir [1];
1819 nd.vray [2] = -rayIn -> rdir [2];
1820 err = SDmapDir(nd.vray, nd.toloc, nd.vray);
1821 }
1822
1823 if (!err)
1824 err = SDinvXform(nd.fromloc, nd.toloc);
1825
1826 if (err) {
1827 objerror(mat, WARNING, "Illegal orientation vector");
1828 return 0;
1829 }
1830
1831 /* Determine BSDF resolution */
1832 err = SDsizeBSDF(nd.sr_vpsa, nd.vray, NULL,
1833 SDqueryMin + SDqueryMax, nd.sd);
1834
1835 if (err)
1836 objerror(mat, USER, transSDError(err));
1837
1838 nd.sr_vpsa [0] = sqrt(nd.sr_vpsa [0]);
1839 nd.sr_vpsa [1] = sqrt(nd.sr_vpsa [1]);
1840
1841 /* Orient perturbed normal towards incident side */
1842 if (!hitFront) {
1843 nd.pnorm [0] = -nd.pnorm [0];
1844 nd.pnorm [1] = -nd.pnorm [1];
1845 nd.pnorm [2] = -nd.pnorm [2];
1846 }
1847
1848 /* Get scatter probabilities (weighted by pattern except for spec refl)
1849 * prDiff, ptDiff: extra diffuse component in material def
1850 * prDiffSD, ptDiffSD: diffuse (constant) component in SDF
1851 * prSpecSD, ptSpecSD: non-diffuse ("specular") component in SDF
1852 * albedo: sum of above, inverse absorption probability */
1853 prDiff = colorAvg(nd.rdiff);
1854 ptDiff = colorAvg(nd.tdiff);
1855 prDiffSD = patAlb * SDdirectHemi(nd.vray, SDsampDf | SDsampR, nd.sd);
1856 ptDiffSD = patAlb * SDdirectHemi(nd.vray, SDsampDf | SDsampT, nd.sd);
1857 prSpecSD = SDdirectHemi(nd.vray, SDsampSp | SDsampR, nd.sd);
1858 ptSpecSD = patAlb * SDdirectHemi(nd.vray, SDsampSp | SDsampT, nd.sd);
1859 albedo = prDiff + ptDiff + prDiffSD + ptDiffSD + prSpecSD + ptSpecSD;
1860
1861 /*
1862 if (albedo > 1)
1863 objerror(mat, WARNING, "Invalid albedo");
1864 */
1865
1866 /* Insert direct and indirect photon hits if diffuse component */
1867 if (prDiff + ptDiff + prDiffSD + ptDiffSD > FTINY)
1868 addPhotons(rayIn);
1869
1870 xi = pmapRandom(rouletteState);
1871
1872 if (xi > albedo)
1873 /* Absorbtion */
1874 return 0;
1875
1876 transmitted = 0;
1877
1878 if ((xi -= prDiff) <= 0) {
1879 /* Diffuse reflection (extra component in material def) */
1880 photonRay(rayIn, &rayOut, PMAP_DIFFREFL, nd.rdiff);
1881 diffPhotonScatter(nd.pnorm, &rayOut);
1882 }
1883
1884 else if ((xi -= ptDiff) <= 0) {
1885 /* Diffuse transmission (extra component in material def) */
1886 photonRay(rayIn, &rayOut, PMAP_DIFFTRANS, nd.tdiff);
1887 diffPhotonScatter(nd.pnorm, &rayOut);
1888 transmitted = 1;
1889 }
1890
1891 else { /* Sample SDF */
1892 if ((xi -= prDiffSD) <= 0) {
1893 /* Diffuse SDF reflection (constant component) */
1894 if ((err = SDsampBSDF(&bsdfVal, nd.vray, pmapRandom(scatterState),
1895 SDsampDf | SDsampR, nd.sd)))
1896 objerror(mat, USER, transSDError(err));
1897
1898 /* Apply pattern to spectral component */
1899 ccy2rgb(&bsdfVal.spec, bsdfVal.cieY, bsdfRGB);
1900 multcolor(bsdfRGB, rayIn -> pcol);
1901 photonRay(rayIn, &rayOut, PMAP_DIFFREFL, bsdfRGB);
1902 }
1903
1904 else if ((xi -= ptDiffSD) <= 0) {
1905 /* Diffuse SDF transmission (constant component) */
1906 if ((err = SDsampBSDF(&bsdfVal, nd.vray, pmapRandom(scatterState),
1907 SDsampDf | SDsampT, nd.sd)))
1908 objerror(mat, USER, transSDError(err));
1909
1910 /* Apply pattern to spectral component */
1911 ccy2rgb(&bsdfVal.spec, bsdfVal.cieY, bsdfRGB);
1912 multcolor(bsdfRGB, rayIn -> pcol);
1913 addcolor(bsdfRGB, nd.tdiff);
1914 photonRay(rayIn, &rayOut, PMAP_DIFFTRANS, bsdfRGB);
1915 transmitted = 1;
1916 }
1917
1918 else if ((xi -= prSpecSD) <= 0) {
1919 /* Non-diffuse ("specular") SDF reflection */
1920 if ((err = SDsampBSDF(&bsdfVal, nd.vray, pmapRandom(scatterState),
1921 SDsampSp | SDsampR, nd.sd)))
1922 objerror(mat, USER, transSDError(err));
1923
1924 ccy2rgb(&bsdfVal.spec, bsdfVal.cieY, bsdfRGB);
1925 photonRay(rayIn, &rayOut, PMAP_SPECREFL, bsdfRGB);
1926 }
1927
1928 else {
1929 /* Non-diffuse ("specular") SDF transmission */
1930 if ((err = SDsampBSDF(&bsdfVal, nd.vray, pmapRandom(scatterState),
1931 SDsampSp | SDsampT, nd.sd)))
1932 objerror(mat, USER, transSDError(err));
1933
1934 /* Apply pattern to spectral component */
1935 ccy2rgb(&bsdfVal.spec, bsdfVal.cieY, bsdfRGB);
1936 multcolor(bsdfRGB, rayIn -> pcol);
1937 photonRay(rayIn, &rayOut, PMAP_SPECTRANS, bsdfRGB);
1938 transmitted = 1;
1939 }
1940
1941 /* Xform outgoing dir to world coords */
1942 if ((err = SDmapDir(rayOut.rdir, nd.fromloc, nd.vray))) {
1943 objerror(mat, USER, transSDError(err));
1944 return 0;
1945 }
1946 }
1947
1948 /* Clean up */
1949 SDfreeCache(nd.sd);
1950
1951 /* Offset outgoing photon origin by thickness to bypass proxy geometry */
1952 if (transmitted && nd.thick != 0)
1953 VSUM(rayOut.rorg, rayOut.rorg, rayIn -> ron, -nd.thick);
1954
1955 tracePhoton(&rayOut);
1956 return 0;
1957 }
1958
1959
1960
1961 static int lightPhotonScatter (OBJREC* mat, RAY* ray)
1962 /* Light sources doan' reflect, mang */
1963 {
1964 return 0;
1965 }
1966
1967
1968
1969 void initPhotonScatterFuncs ()
1970 /* Init photonScatter[] dispatch table */
1971 {
1972 int i;
1973
1974 /* Catch-all for inconsistencies */
1975 for (i = 0; i < NUMOTYPE; i++)
1976 photonScatter [i] = o_default;
1977
1978 photonScatter [MAT_LIGHT] = photonScatter [MAT_ILLUM] =
1979 photonScatter [MAT_GLOW] = photonScatter [MAT_SPOT] =
1980 lightPhotonScatter;
1981
1982 photonScatter [MAT_PLASTIC] = photonScatter [MAT_METAL] =
1983 photonScatter [MAT_TRANS] = normalPhotonScatter;
1984
1985 photonScatter [MAT_PLASTIC2] = photonScatter [MAT_METAL2] =
1986 photonScatter [MAT_TRANS2] = anisoPhotonScatter;
1987
1988 photonScatter [MAT_DIELECTRIC] = photonScatter [MAT_INTERFACE] =
1989 dielectricPhotonScatter;
1990
1991 photonScatter [MAT_MIST] = mistPhotonScatter;
1992 photonScatter [MAT_GLASS] = glassPhotonScatter;
1993 photonScatter [MAT_CLIP] = clipPhotonScatter;
1994 photonScatter [MAT_MIRROR] = mirrorPhotonScatter;
1995 photonScatter [MIX_FUNC] = mx_funcPhotonScatter;
1996 photonScatter [MIX_DATA] = mx_dataPhotonScatter;
1997 photonScatter [MIX_PICT]= mx_pdataPhotonScatter;
1998
1999 photonScatter [PAT_BDATA] = photonScatter [PAT_CDATA] =
2000 photonScatter [PAT_BFUNC] = photonScatter [PAT_CFUNC] =
2001 photonScatter [PAT_CPICT] = photonScatter [TEX_FUNC] =
2002 photonScatter [TEX_DATA] = pattexPhotonScatter;
2003
2004 photonScatter [MOD_ALIAS] = aliasPhotonScatter;
2005 photonScatter [MAT_BRTDF] = brdfPhotonScatter;
2006
2007 photonScatter [MAT_PFUNC] = photonScatter [MAT_MFUNC] =
2008 photonScatter [MAT_PDATA] = photonScatter [MAT_MDATA] =
2009 photonScatter [MAT_TFUNC] = photonScatter [MAT_TDATA] =
2010 brdf2PhotonScatter;
2011
2012 photonScatter [MAT_BSDF] = photonScatter [MAT_ABSDF] =
2013 bsdfPhotonScatter;
2014 }