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root/radiance/ray/src/rt/raytrace.c
Revision: 2.65
Committed: Wed Feb 19 14:12:48 2014 UTC (10 years, 1 month ago) by greg
Content type: text/plain
Branch: MAIN
CVS Tags: rad4R2P2, rad4R2, rad4R2P1
Changes since 2.64: +17 -17 lines
Log Message:
Eliminated superfluous extern declarations

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: raytrace.c,v 2.64 2012/06/01 19:17:17 greg Exp $";
3 #endif
4 /*
5 * raytrace.c - routines for tracing and shading rays.
6 *
7 * External symbols declared in ray.h
8 */
9
10 #include "copyright.h"
11
12 #include "ray.h"
13 #include "source.h"
14 #include "otypes.h"
15 #include "otspecial.h"
16 #include "random.h"
17
18 #define MAXCSET ((MAXSET+1)*2-1) /* maximum check set size */
19
20 RNUMBER raynum = 0; /* next unique ray number */
21 RNUMBER nrays = 0; /* number of calls to localhit */
22
23 static RREAL Lambfa[5] = {PI, PI, PI, 0.0, 0.0};
24 OBJREC Lamb = {
25 OVOID, MAT_PLASTIC, "Lambertian",
26 {NULL, Lambfa, 0, 5}, NULL
27 }; /* a Lambertian surface */
28
29 OBJREC Aftplane; /* aft clipping plane object */
30
31 #define RAYHIT (-1) /* return value for intercepted ray */
32
33 static int raymove(FVECT pos, OBJECT *cxs, int dirf, RAY *r, CUBE *cu);
34 static int checkhit(RAY *r, CUBE *cu, OBJECT *cxs);
35 static void checkset(OBJECT *os, OBJECT *cs);
36
37
38 int
39 rayorigin( /* start new ray from old one */
40 RAY *r,
41 int rt,
42 const RAY *ro,
43 const COLOR rc
44 )
45 {
46 double rw, re;
47 /* assign coefficient/weight */
48 if (rc == NULL) {
49 rw = 1.0;
50 setcolor(r->rcoef, 1., 1., 1.);
51 } else {
52 rw = intens(rc);
53 if (rc != r->rcoef)
54 copycolor(r->rcoef, rc);
55 }
56 if ((r->parent = ro) == NULL) { /* primary ray */
57 r->rlvl = 0;
58 r->rweight = rw;
59 r->crtype = r->rtype = rt;
60 r->rsrc = -1;
61 r->clipset = NULL;
62 r->revf = raytrace;
63 copycolor(r->cext, cextinction);
64 copycolor(r->albedo, salbedo);
65 r->gecc = seccg;
66 r->slights = NULL;
67 } else { /* spawned ray */
68 if (ro->rot >= FHUGE) {
69 memset(r, 0, sizeof(RAY));
70 return(-1); /* illegal continuation */
71 }
72 r->rlvl = ro->rlvl;
73 if (rt & RAYREFL) {
74 r->rlvl++;
75 r->rsrc = -1;
76 r->clipset = ro->clipset;
77 r->rmax = 0.0;
78 } else {
79 r->rsrc = ro->rsrc;
80 r->clipset = ro->newcset;
81 r->rmax = ro->rmax <= FTINY ? 0.0 : ro->rmax - ro->rot;
82 }
83 r->revf = ro->revf;
84 copycolor(r->cext, ro->cext);
85 copycolor(r->albedo, ro->albedo);
86 r->gecc = ro->gecc;
87 r->slights = ro->slights;
88 r->crtype = ro->crtype | (r->rtype = rt);
89 VCOPY(r->rorg, ro->rop);
90 r->rweight = ro->rweight * rw;
91 /* estimate extinction */
92 re = colval(ro->cext,RED) < colval(ro->cext,GRN) ?
93 colval(ro->cext,RED) : colval(ro->cext,GRN);
94 if (colval(ro->cext,BLU) < re) re = colval(ro->cext,BLU);
95 re *= ro->rot;
96 if (re > 0.1) {
97 if (re > 92.) {
98 r->rweight = 0.0;
99 } else {
100 r->rweight *= exp(-re);
101 }
102 }
103 }
104 rayclear(r);
105 if (r->rweight <= 0.0) /* check for expiration */
106 return(-1);
107 if (r->crtype & SHADOW) /* shadow commitment */
108 return(0);
109 if (maxdepth <= 0 && rc != NULL) { /* Russian roulette */
110 if (minweight <= 0.0)
111 error(USER, "zero ray weight in Russian roulette");
112 if (maxdepth < 0 && r->rlvl > -maxdepth)
113 return(-1); /* upper reflection limit */
114 if (r->rweight >= minweight)
115 return(0);
116 if (frandom() > r->rweight/minweight)
117 return(-1);
118 rw = minweight/r->rweight; /* promote survivor */
119 scalecolor(r->rcoef, rw);
120 r->rweight = minweight;
121 return(0);
122 }
123 return(r->rweight >= minweight && r->rlvl <= abs(maxdepth) ? 0 : -1);
124 }
125
126
127 void
128 rayclear( /* clear a ray for (re)evaluation */
129 RAY *r
130 )
131 {
132 r->rno = raynum++;
133 r->newcset = r->clipset;
134 r->hitf = rayhit;
135 r->robj = OVOID;
136 r->ro = NULL;
137 r->rox = NULL;
138 r->rt = r->rot = FHUGE;
139 r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
140 r->uv[0] = r->uv[1] = 0.0;
141 setcolor(r->pcol, 1.0, 1.0, 1.0);
142 setcolor(r->rcol, 0.0, 0.0, 0.0);
143 }
144
145
146 void
147 raytrace( /* trace a ray and compute its value */
148 RAY *r
149 )
150 {
151 if (localhit(r, &thescene))
152 raycont(r); /* hit local surface, evaluate */
153 else if (r->ro == &Aftplane) {
154 r->ro = NULL; /* hit aft clipping plane */
155 r->rot = FHUGE;
156 } else if (sourcehit(r))
157 rayshade(r, r->ro->omod); /* distant source */
158
159 if (trace != NULL)
160 (*trace)(r); /* trace execution */
161
162 rayparticipate(r); /* for participating medium */
163 }
164
165
166 void
167 raycont( /* check for clipped object and continue */
168 RAY *r
169 )
170 {
171 if ((r->clipset != NULL && inset(r->clipset, r->ro->omod)) ||
172 !rayshade(r, r->ro->omod))
173 raytrans(r);
174 }
175
176
177 void
178 raytrans( /* transmit ray as is */
179 RAY *r
180 )
181 {
182 RAY tr;
183
184 if (rayorigin(&tr, TRANS, r, NULL) == 0) {
185 VCOPY(tr.rdir, r->rdir);
186 rayvalue(&tr);
187 copycolor(r->rcol, tr.rcol);
188 r->rt = r->rot + tr.rt;
189 }
190 }
191
192
193 int
194 rayshade( /* shade ray r with material mod */
195 RAY *r,
196 int mod
197 )
198 {
199 OBJREC *m;
200
201 r->rt = r->rot; /* set effective ray length */
202 for ( ; mod != OVOID; mod = m->omod) {
203 m = objptr(mod);
204 /****** unnecessary test since modifier() is always called
205 if (!ismodifier(m->otype)) {
206 sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
207 error(USER, errmsg);
208 }
209 ******/
210 /* hack for irradiance calculation */
211 if (do_irrad && !(r->crtype & ~(PRIMARY|TRANS)) &&
212 m->otype != MAT_CLIP &&
213 (ofun[m->otype].flags & (T_M|T_X))) {
214 if (irr_ignore(m->otype)) {
215 raytrans(r);
216 return(1);
217 }
218 if (!islight(m->otype))
219 m = &Lamb;
220 }
221 if ((*ofun[m->otype].funp)(m, r))
222 return(1); /* materials call raytexture() */
223 }
224 return(0); /* no material! */
225 }
226
227
228 void
229 rayparticipate( /* compute ray medium participation */
230 RAY *r
231 )
232 {
233 COLOR ce, ca;
234 double re, ge, be;
235
236 if (intens(r->cext) <= 1./FHUGE)
237 return; /* no medium */
238 re = r->rot*colval(r->cext,RED);
239 ge = r->rot*colval(r->cext,GRN);
240 be = r->rot*colval(r->cext,BLU);
241 if (r->crtype & SHADOW) { /* no scattering for sources */
242 re *= 1. - colval(r->albedo,RED);
243 ge *= 1. - colval(r->albedo,GRN);
244 be *= 1. - colval(r->albedo,BLU);
245 }
246 setcolor(ce, re<=FTINY ? 1. : re>92. ? 0. : exp(-re),
247 ge<=FTINY ? 1. : ge>92. ? 0. : exp(-ge),
248 be<=FTINY ? 1. : be>92. ? 0. : exp(-be));
249 multcolor(r->rcol, ce); /* path extinction */
250 if (r->crtype & SHADOW || intens(r->albedo) <= FTINY)
251 return; /* no scattering */
252 setcolor(ca,
253 colval(r->albedo,RED)*colval(ambval,RED)*(1.-colval(ce,RED)),
254 colval(r->albedo,GRN)*colval(ambval,GRN)*(1.-colval(ce,GRN)),
255 colval(r->albedo,BLU)*colval(ambval,BLU)*(1.-colval(ce,BLU)));
256 addcolor(r->rcol, ca); /* ambient in scattering */
257 srcscatter(r); /* source in scattering */
258 }
259
260
261 void
262 raytexture( /* get material modifiers */
263 RAY *r,
264 OBJECT mod
265 )
266 {
267 OBJREC *m;
268 /* execute textures and patterns */
269 for ( ; mod != OVOID; mod = m->omod) {
270 m = objptr(mod);
271 /****** unnecessary test since modifier() is always called
272 if (!ismodifier(m->otype)) {
273 sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
274 error(USER, errmsg);
275 }
276 ******/
277 if ((*ofun[m->otype].funp)(m, r)) {
278 sprintf(errmsg, "conflicting material \"%s\"",
279 m->oname);
280 objerror(r->ro, USER, errmsg);
281 }
282 }
283 }
284
285
286 int
287 raymixture( /* mix modifiers */
288 RAY *r,
289 OBJECT fore,
290 OBJECT back,
291 double coef
292 )
293 {
294 RAY fr, br;
295 int foremat, backmat;
296 int i;
297 /* bound coefficient */
298 if (coef > 1.0)
299 coef = 1.0;
300 else if (coef < 0.0)
301 coef = 0.0;
302 /* compute foreground and background */
303 foremat = backmat = 0;
304 /* foreground */
305 fr = *r;
306 if (coef > FTINY) {
307 fr.rweight *= coef;
308 scalecolor(fr.rcoef, coef);
309 foremat = rayshade(&fr, fore);
310 }
311 /* background */
312 br = *r;
313 if (coef < 1.0-FTINY) {
314 br.rweight *= 1.0-coef;
315 scalecolor(br.rcoef, 1.0-coef);
316 backmat = rayshade(&br, back);
317 }
318 /* check for transparency */
319 if (backmat ^ foremat) {
320 if (backmat && coef > FTINY)
321 raytrans(&fr);
322 else if (foremat && coef < 1.0-FTINY)
323 raytrans(&br);
324 }
325 /* mix perturbations */
326 for (i = 0; i < 3; i++)
327 r->pert[i] = coef*fr.pert[i] + (1.0-coef)*br.pert[i];
328 /* mix pattern colors */
329 scalecolor(fr.pcol, coef);
330 scalecolor(br.pcol, 1.0-coef);
331 copycolor(r->pcol, fr.pcol);
332 addcolor(r->pcol, br.pcol);
333 /* return value tells if material */
334 if (!foremat & !backmat)
335 return(0);
336 /* mix returned ray values */
337 scalecolor(fr.rcol, coef);
338 scalecolor(br.rcol, 1.0-coef);
339 copycolor(r->rcol, fr.rcol);
340 addcolor(r->rcol, br.rcol);
341 r->rt = bright(fr.rcol) > bright(br.rcol) ? fr.rt : br.rt;
342 return(1);
343 }
344
345
346 double
347 raydist( /* compute (cumulative) ray distance */
348 const RAY *r,
349 int flags
350 )
351 {
352 double sum = 0.0;
353
354 while (r != NULL && r->crtype&flags) {
355 sum += r->rot;
356 r = r->parent;
357 }
358 return(sum);
359 }
360
361
362 void
363 raycontrib( /* compute (cumulative) ray contribution */
364 RREAL rc[3],
365 const RAY *r,
366 int flags
367 )
368 {
369 double eext[3];
370 int i;
371
372 eext[0] = eext[1] = eext[2] = 0.;
373 rc[0] = rc[1] = rc[2] = 1.;
374
375 while (r != NULL && r->crtype&flags) {
376 for (i = 3; i--; ) {
377 rc[i] *= colval(r->rcoef,i);
378 eext[i] += r->rot * colval(r->cext,i);
379 }
380 r = r->parent;
381 }
382 for (i = 3; i--; )
383 rc[i] *= (eext[i] <= FTINY) ? 1. :
384 (eext[i] > 92.) ? 0. : exp(-eext[i]);
385 }
386
387
388 double
389 raynormal( /* compute perturbed normal for ray */
390 FVECT norm,
391 RAY *r
392 )
393 {
394 double newdot;
395 int i;
396
397 /* The perturbation is added to the surface normal to obtain
398 * the new normal. If the new normal would affect the surface
399 * orientation wrt. the ray, a correction is made. The method is
400 * still fraught with problems since reflected rays and similar
401 * directions calculated from the surface normal may spawn rays behind
402 * the surface. The only solution is to curb textures at high
403 * incidence (namely, keep DOT(rdir,pert) < Rdot).
404 */
405
406 for (i = 0; i < 3; i++)
407 norm[i] = r->ron[i] + r->pert[i];
408
409 if (normalize(norm) == 0.0) {
410 objerror(r->ro, WARNING, "illegal normal perturbation");
411 VCOPY(norm, r->ron);
412 return(r->rod);
413 }
414 newdot = -DOT(norm, r->rdir);
415 if ((newdot > 0.0) != (r->rod > 0.0)) { /* fix orientation */
416 for (i = 0; i < 3; i++)
417 norm[i] += 2.0*newdot*r->rdir[i];
418 newdot = -newdot;
419 }
420 return(newdot);
421 }
422
423
424 void
425 newrayxf( /* get new tranformation matrix for ray */
426 RAY *r
427 )
428 {
429 static struct xfn {
430 struct xfn *next;
431 FULLXF xf;
432 } xfseed = { &xfseed }, *xflast = &xfseed;
433 struct xfn *xp;
434 const RAY *rp;
435
436 /*
437 * Search for transform in circular list that
438 * has no associated ray in the tree.
439 */
440 xp = xflast;
441 for (rp = r->parent; rp != NULL; rp = rp->parent)
442 if (rp->rox == &xp->xf) { /* xp in use */
443 xp = xp->next; /* move to next */
444 if (xp == xflast) { /* need new one */
445 xp = (struct xfn *)bmalloc(sizeof(struct xfn));
446 if (xp == NULL)
447 error(SYSTEM,
448 "out of memory in newrayxf");
449 /* insert in list */
450 xp->next = xflast->next;
451 xflast->next = xp;
452 break; /* we're done */
453 }
454 rp = r; /* start check over */
455 }
456 /* got it */
457 r->rox = &xp->xf;
458 xflast = xp;
459 }
460
461
462 void
463 flipsurface( /* reverse surface orientation */
464 RAY *r
465 )
466 {
467 r->rod = -r->rod;
468 r->ron[0] = -r->ron[0];
469 r->ron[1] = -r->ron[1];
470 r->ron[2] = -r->ron[2];
471 r->pert[0] = -r->pert[0];
472 r->pert[1] = -r->pert[1];
473 r->pert[2] = -r->pert[2];
474 }
475
476
477 void
478 rayhit( /* standard ray hit test */
479 OBJECT *oset,
480 RAY *r
481 )
482 {
483 OBJREC *o;
484 int i;
485
486 for (i = oset[0]; i > 0; i--) {
487 o = objptr(oset[i]);
488 if ((*ofun[o->otype].funp)(o, r))
489 r->robj = oset[i];
490 }
491 }
492
493
494 int
495 localhit( /* check for hit in the octree */
496 RAY *r,
497 CUBE *scene
498 )
499 {
500 OBJECT cxset[MAXCSET+1]; /* set of checked objects */
501 FVECT curpos; /* current cube position */
502 int sflags; /* sign flags */
503 double t, dt;
504 int i;
505
506 nrays++; /* increment trace counter */
507 sflags = 0;
508 for (i = 0; i < 3; i++) {
509 curpos[i] = r->rorg[i];
510 if (r->rdir[i] > 1e-7)
511 sflags |= 1 << i;
512 else if (r->rdir[i] < -1e-7)
513 sflags |= 0x10 << i;
514 }
515 if (!sflags) {
516 error(WARNING, "zero ray direction in localhit");
517 return(0);
518 }
519 /* start off assuming nothing hit */
520 if (r->rmax > FTINY) { /* except aft plane if one */
521 r->ro = &Aftplane;
522 r->rot = r->rmax;
523 VSUM(r->rop, r->rorg, r->rdir, r->rot);
524 }
525 /* find global cube entrance point */
526 t = 0.0;
527 if (!incube(scene, curpos)) {
528 /* find distance to entry */
529 for (i = 0; i < 3; i++) {
530 /* plane in our direction */
531 if (sflags & 1<<i)
532 dt = scene->cuorg[i];
533 else if (sflags & 0x10<<i)
534 dt = scene->cuorg[i] + scene->cusize;
535 else
536 continue;
537 /* distance to the plane */
538 dt = (dt - r->rorg[i])/r->rdir[i];
539 if (dt > t)
540 t = dt; /* farthest face is the one */
541 }
542 t += FTINY; /* fudge to get inside cube */
543 if (t >= r->rot) /* clipped already */
544 return(0);
545 /* advance position */
546 VSUM(curpos, curpos, r->rdir, t);
547
548 if (!incube(scene, curpos)) /* non-intersecting ray */
549 return(0);
550 }
551 cxset[0] = 0;
552 raymove(curpos, cxset, sflags, r, scene);
553 return((r->ro != NULL) & (r->ro != &Aftplane));
554 }
555
556
557 static int
558 raymove( /* check for hit as we move */
559 FVECT pos, /* current position, modified herein */
560 OBJECT *cxs, /* checked objects, modified by checkhit */
561 int dirf, /* direction indicators to speed tests */
562 RAY *r,
563 CUBE *cu
564 )
565 {
566 int ax;
567 double dt, t;
568
569 if (istree(cu->cutree)) { /* recurse on subcubes */
570 CUBE cukid;
571 int br, sgn;
572
573 cukid.cusize = cu->cusize * 0.5; /* find subcube */
574 VCOPY(cukid.cuorg, cu->cuorg);
575 br = 0;
576 if (pos[0] >= cukid.cuorg[0]+cukid.cusize) {
577 cukid.cuorg[0] += cukid.cusize;
578 br |= 1;
579 }
580 if (pos[1] >= cukid.cuorg[1]+cukid.cusize) {
581 cukid.cuorg[1] += cukid.cusize;
582 br |= 2;
583 }
584 if (pos[2] >= cukid.cuorg[2]+cukid.cusize) {
585 cukid.cuorg[2] += cukid.cusize;
586 br |= 4;
587 }
588 for ( ; ; ) {
589 cukid.cutree = octkid(cu->cutree, br);
590 if ((ax = raymove(pos,cxs,dirf,r,&cukid)) == RAYHIT)
591 return(RAYHIT);
592 sgn = 1 << ax;
593 if (sgn & dirf) /* positive axis? */
594 if (sgn & br)
595 return(ax); /* overflow */
596 else {
597 cukid.cuorg[ax] += cukid.cusize;
598 br |= sgn;
599 }
600 else
601 if (sgn & br) {
602 cukid.cuorg[ax] -= cukid.cusize;
603 br &= ~sgn;
604 } else
605 return(ax); /* underflow */
606 }
607 /*NOTREACHED*/
608 }
609 if (isfull(cu->cutree)) {
610 if (checkhit(r, cu, cxs))
611 return(RAYHIT);
612 } else if (r->ro == &Aftplane && incube(cu, r->rop))
613 return(RAYHIT);
614 /* advance to next cube */
615 if (dirf&0x11) {
616 dt = dirf&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0];
617 t = (dt - pos[0])/r->rdir[0];
618 ax = 0;
619 } else
620 t = FHUGE;
621 if (dirf&0x22) {
622 dt = dirf&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1];
623 dt = (dt - pos[1])/r->rdir[1];
624 if (dt < t) {
625 t = dt;
626 ax = 1;
627 }
628 }
629 if (dirf&0x44) {
630 dt = dirf&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2];
631 dt = (dt - pos[2])/r->rdir[2];
632 if (dt < t) {
633 t = dt;
634 ax = 2;
635 }
636 }
637 VSUM(pos, pos, r->rdir, t);
638 return(ax);
639 }
640
641
642 static int
643 checkhit( /* check for hit in full cube */
644 RAY *r,
645 CUBE *cu,
646 OBJECT *cxs
647 )
648 {
649 OBJECT oset[MAXSET+1];
650
651 objset(oset, cu->cutree);
652 checkset(oset, cxs); /* avoid double-checking */
653
654 (*r->hitf)(oset, r); /* test for hit in set */
655
656 if (r->robj == OVOID)
657 return(0); /* no scores yet */
658
659 return(incube(cu, r->rop)); /* hit OK if in current cube */
660 }
661
662
663 static void
664 checkset( /* modify checked set and set to check */
665 OBJECT *os, /* os' = os - cs */
666 OBJECT *cs /* cs' = cs + os */
667 )
668 {
669 OBJECT cset[MAXCSET+MAXSET+1];
670 int i, j;
671 int k;
672 /* copy os in place, cset <- cs */
673 cset[0] = 0;
674 k = 0;
675 for (i = j = 1; i <= os[0]; i++) {
676 while (j <= cs[0] && cs[j] < os[i])
677 cset[++cset[0]] = cs[j++];
678 if (j > cs[0] || os[i] != cs[j]) { /* object to check */
679 os[++k] = os[i];
680 cset[++cset[0]] = os[i];
681 }
682 }
683 if (!(os[0] = k)) /* new "to check" set size */
684 return; /* special case */
685 while (j <= cs[0]) /* get the rest of cs */
686 cset[++cset[0]] = cs[j++];
687 if (cset[0] > MAXCSET) /* truncate "checked" set if nec. */
688 cset[0] = MAXCSET;
689 /* setcopy(cs, cset); */ /* copy cset back to cs */
690 os = cset;
691 for (i = os[0]; i-- >= 0; )
692 *cs++ = *os++;
693 }