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root/radiance/ray/src/rt/raytrace.c
Revision: 2.21
Committed: Thu Nov 2 17:38:02 1995 UTC (28 years, 6 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.20: +15 -0 lines
Log Message:
added raydist() function

File Contents

# Content
1 /* Copyright (c) 1995 Regents of the University of California */
2
3 #ifndef lint
4 static char SCCSid[] = "$SunId$ LBL";
5 #endif
6
7 /*
8 * raytrace.c - routines for tracing and shading rays.
9 *
10 * 8/7/85
11 */
12
13 #include "ray.h"
14
15 #include "octree.h"
16
17 #include "otypes.h"
18
19 #include "otspecial.h"
20
21 #define MAXCSET ((MAXSET+1)*2-1) /* maximum check set size */
22
23 extern CUBE thescene; /* our scene */
24 extern int maxdepth; /* maximum recursion depth */
25 extern double minweight; /* minimum ray weight */
26 extern int do_irrad; /* compute irradiance? */
27
28 unsigned long raynum = 0; /* next unique ray number */
29 unsigned long nrays = 0; /* number of calls to localhit */
30
31 static FLOAT Lambfa[5] = {PI, PI, PI, 0.0, 0.0};
32 OBJREC Lamb = {
33 OVOID, MAT_PLASTIC, "Lambertian",
34 {0, 5, NULL, Lambfa}, NULL,
35 }; /* a Lambertian surface */
36
37 OBJREC Aftplane; /* aft clipping plane object */
38
39 static int raymove(), checkset(), checkhit();
40
41 #define MAXLOOP 128 /* modifier loop detection */
42
43 #define RAYHIT (-1) /* return value for intercepted ray */
44
45
46 rayorigin(r, ro, rt, rw) /* start new ray from old one */
47 register RAY *r, *ro;
48 int rt;
49 double rw;
50 {
51 if ((r->parent = ro) == NULL) { /* primary ray */
52 r->rlvl = 0;
53 r->rweight = rw;
54 r->crtype = r->rtype = rt;
55 r->rsrc = -1;
56 r->clipset = NULL;
57 r->revf = raytrace;
58 } else { /* spawned ray */
59 r->rlvl = ro->rlvl;
60 if (rt & RAYREFL) {
61 r->rlvl++;
62 r->rsrc = -1;
63 r->clipset = ro->clipset;
64 } else {
65 r->rsrc = ro->rsrc;
66 r->clipset = ro->newcset;
67 }
68 r->revf = ro->revf;
69 r->rweight = ro->rweight * rw;
70 r->crtype = ro->crtype | (r->rtype = rt);
71 VCOPY(r->rorg, ro->rop);
72 r->rmax = 0.0;
73 }
74 rayclear(r);
75 return(r->rlvl <= maxdepth && r->rweight >= minweight ? 0 : -1);
76 }
77
78
79 rayclear(r) /* clear a ray for (re)evaluation */
80 register RAY *r;
81 {
82 r->rno = raynum++;
83 r->newcset = r->clipset;
84 r->ro = NULL;
85 r->rot = FHUGE;
86 r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
87 setcolor(r->pcol, 1.0, 1.0, 1.0);
88 setcolor(r->rcol, 0.0, 0.0, 0.0);
89 r->rt = 0.0;
90 }
91
92
93 raytrace(r) /* trace a ray and compute its value */
94 RAY *r;
95 {
96 extern int (*trace)();
97 int gotmat;
98
99 if (localhit(r, &thescene))
100 gotmat = raycont(r);
101 else if (r->ro == &Aftplane) {
102 r->ro = NULL;
103 r->rot = FHUGE;
104 } else if (sourcehit(r))
105 gotmat = rayshade(r, r->ro->omod);
106
107 if (r->ro != NULL && !gotmat)
108 objerror(r->ro, USER, "material not found");
109
110 if (trace != NULL)
111 (*trace)(r); /* trace execution */
112 }
113
114
115 raycont(r) /* check for clipped object and continue */
116 register RAY *r;
117 {
118 if ((r->clipset != NULL && inset(r->clipset, r->ro->omod)) ||
119 r->ro->omod == OVOID) {
120 raytrans(r);
121 return(1);
122 }
123 return(rayshade(r, r->ro->omod));
124 }
125
126
127 raytrans(r) /* transmit ray as is */
128 register RAY *r;
129 {
130 RAY tr;
131
132 if (rayorigin(&tr, r, TRANS, 1.0) == 0) {
133 VCOPY(tr.rdir, r->rdir);
134 if (r->rmax > FTINY)
135 tr.rmax = r->rmax - r->rot;
136 rayvalue(&tr);
137 copycolor(r->rcol, tr.rcol);
138 r->rt = r->rot + tr.rt;
139 }
140 }
141
142
143 rayshade(r, mod) /* shade ray r with material mod */
144 register RAY *r;
145 int mod;
146 {
147 static int depth = 0;
148 int gotmat;
149 register OBJREC *m;
150 /* check for infinite loop */
151 if (depth++ >= MAXLOOP)
152 objerror(r->ro, USER, "possible modifier loop");
153 r->rt = r->rot; /* set effective ray length */
154 for (gotmat = 0; !gotmat && mod != OVOID; mod = m->omod) {
155 m = objptr(mod);
156 /****** unnecessary test since modifier() is always called
157 if (!ismodifier(m->otype)) {
158 sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
159 error(USER, errmsg);
160 }
161 ******/
162 /* hack for irradiance calculation */
163 if (do_irrad && !(r->crtype & ~(PRIMARY|TRANS))) {
164 if (irr_ignore(m->otype)) {
165 depth--;
166 raytrans(r);
167 return(1);
168 }
169 if (!islight(m->otype))
170 m = &Lamb;
171 }
172 /* materials call raytexture */
173 gotmat = (*ofun[m->otype].funp)(m, r);
174 }
175 depth--;
176 return(gotmat);
177 }
178
179
180 raytexture(r, mod) /* get material modifiers */
181 RAY *r;
182 int mod;
183 {
184 static int depth = 0;
185 register OBJREC *m;
186 /* check for infinite loop */
187 if (depth++ >= MAXLOOP)
188 objerror(r->ro, USER, "modifier loop");
189 /* execute textures and patterns */
190 for ( ; mod != OVOID; mod = m->omod) {
191 m = objptr(mod);
192 /****** unnecessary test since modifier() is always called
193 if (!ismodifier(m->otype)) {
194 sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
195 error(USER, errmsg);
196 }
197 ******/
198 if ((*ofun[m->otype].funp)(m, r)) {
199 sprintf(errmsg, "conflicting material \"%s\"",
200 m->oname);
201 objerror(r->ro, USER, errmsg);
202 }
203 }
204 depth--; /* end here */
205 }
206
207
208 raymixture(r, fore, back, coef) /* mix modifiers */
209 register RAY *r;
210 OBJECT fore, back;
211 double coef;
212 {
213 RAY fr, br;
214 int foremat, backmat;
215 register int i;
216 /* clip coefficient */
217 if (coef > 1.0)
218 coef = 1.0;
219 else if (coef < 0.0)
220 coef = 0.0;
221 /* compute foreground and background */
222 foremat = backmat = -1;
223 /* foreground */
224 copystruct(&fr, r);
225 if (fore != OVOID && coef > FTINY)
226 foremat = rayshade(&fr, fore);
227 /* background */
228 copystruct(&br, r);
229 if (back != OVOID && coef < 1.0-FTINY)
230 backmat = rayshade(&br, back);
231 /* check */
232 if (foremat < 0)
233 if (backmat < 0)
234 foremat = backmat = 0;
235 else
236 foremat = backmat;
237 else if (backmat < 0)
238 backmat = foremat;
239 if ((foremat==0) != (backmat==0))
240 objerror(r->ro, USER, "mixing material with non-material");
241 /* mix perturbations */
242 for (i = 0; i < 3; i++)
243 r->pert[i] = coef*fr.pert[i] + (1.0-coef)*br.pert[i];
244 /* mix pattern colors */
245 scalecolor(fr.pcol, coef);
246 scalecolor(br.pcol, 1.0-coef);
247 copycolor(r->pcol, fr.pcol);
248 addcolor(r->pcol, br.pcol);
249 /* mix returned ray values */
250 if (foremat) {
251 scalecolor(fr.rcol, coef);
252 scalecolor(br.rcol, 1.0-coef);
253 copycolor(r->rcol, fr.rcol);
254 addcolor(r->rcol, br.rcol);
255 r->rt = bright(fr.rcol) > bright(br.rcol) ? fr.rt : br.rt;
256 }
257 /* return value tells if material */
258 return(foremat);
259 }
260
261
262 double
263 raydist(r, flags) /* compute (cumulative) ray distance */
264 register RAY *r;
265 register int flags;
266 {
267 double sum = 0.0;
268
269 while (r != NULL && r->crtype&flags) {
270 sum += r->rot;
271 r = r->parent;
272 }
273 return(sum);
274 }
275
276
277 double
278 raynormal(norm, r) /* compute perturbed normal for ray */
279 FVECT norm;
280 register RAY *r;
281 {
282 double newdot;
283 register int i;
284
285 /* The perturbation is added to the surface normal to obtain
286 * the new normal. If the new normal would affect the surface
287 * orientation wrt. the ray, a correction is made. The method is
288 * still fraught with problems since reflected rays and similar
289 * directions calculated from the surface normal may spawn rays behind
290 * the surface. The only solution is to curb textures at high
291 * incidence (namely, keep DOT(rdir,pert) < Rdot).
292 */
293
294 for (i = 0; i < 3; i++)
295 norm[i] = r->ron[i] + r->pert[i];
296
297 if (normalize(norm) == 0.0) {
298 objerror(r->ro, WARNING, "illegal normal perturbation");
299 VCOPY(norm, r->ron);
300 return(r->rod);
301 }
302 newdot = -DOT(norm, r->rdir);
303 if ((newdot > 0.0) != (r->rod > 0.0)) { /* fix orientation */
304 for (i = 0; i < 3; i++)
305 norm[i] += 2.0*newdot*r->rdir[i];
306 newdot = -newdot;
307 }
308 return(newdot);
309 }
310
311
312 newrayxf(r) /* get new tranformation matrix for ray */
313 RAY *r;
314 {
315 static struct xfn {
316 struct xfn *next;
317 FULLXF xf;
318 } xfseed = { &xfseed }, *xflast = &xfseed;
319 register struct xfn *xp;
320 register RAY *rp;
321
322 /*
323 * Search for transform in circular list that
324 * has no associated ray in the tree.
325 */
326 xp = xflast;
327 for (rp = r->parent; rp != NULL; rp = rp->parent)
328 if (rp->rox == &xp->xf) { /* xp in use */
329 xp = xp->next; /* move to next */
330 if (xp == xflast) { /* need new one */
331 xp = (struct xfn *)bmalloc(sizeof(struct xfn));
332 if (xp == NULL)
333 error(SYSTEM,
334 "out of memory in newrayxf");
335 /* insert in list */
336 xp->next = xflast->next;
337 xflast->next = xp;
338 break; /* we're done */
339 }
340 rp = r; /* start check over */
341 }
342 /* got it */
343 r->rox = &xp->xf;
344 xflast = xp;
345 }
346
347
348 flipsurface(r) /* reverse surface orientation */
349 register RAY *r;
350 {
351 r->rod = -r->rod;
352 r->ron[0] = -r->ron[0];
353 r->ron[1] = -r->ron[1];
354 r->ron[2] = -r->ron[2];
355 r->pert[0] = -r->pert[0];
356 r->pert[1] = -r->pert[1];
357 r->pert[2] = -r->pert[2];
358 }
359
360
361 localhit(r, scene) /* check for hit in the octree */
362 register RAY *r;
363 register CUBE *scene;
364 {
365 OBJECT cxset[MAXCSET+1]; /* set of checked objects */
366 FVECT curpos; /* current cube position */
367 int sflags; /* sign flags */
368 double t, dt;
369 register int i;
370
371 nrays++; /* increment trace counter */
372 sflags = 0;
373 for (i = 0; i < 3; i++) {
374 curpos[i] = r->rorg[i];
375 if (r->rdir[i] > 1e-7)
376 sflags |= 1 << i;
377 else if (r->rdir[i] < -1e-7)
378 sflags |= 0x10 << i;
379 }
380 if (sflags == 0)
381 error(CONSISTENCY, "zero ray direction in localhit");
382 /* start off assuming nothing hit */
383 if (r->rmax > FTINY) { /* except aft plane if one */
384 r->ro = &Aftplane;
385 r->rot = r->rmax;
386 for (i = 0; i < 3; i++)
387 r->rop[i] = r->rorg[i] + r->rot*r->rdir[i];
388 }
389 /* find global cube entrance point */
390 t = 0.0;
391 if (!incube(scene, curpos)) {
392 /* find distance to entry */
393 for (i = 0; i < 3; i++) {
394 /* plane in our direction */
395 if (sflags & 1<<i)
396 dt = scene->cuorg[i];
397 else if (sflags & 0x10<<i)
398 dt = scene->cuorg[i] + scene->cusize;
399 else
400 continue;
401 /* distance to the plane */
402 dt = (dt - r->rorg[i])/r->rdir[i];
403 if (dt > t)
404 t = dt; /* farthest face is the one */
405 }
406 t += FTINY; /* fudge to get inside cube */
407 if (t >= r->rot) /* clipped already */
408 return(0);
409 /* advance position */
410 for (i = 0; i < 3; i++)
411 curpos[i] += r->rdir[i]*t;
412
413 if (!incube(scene, curpos)) /* non-intersecting ray */
414 return(0);
415 }
416 cxset[0] = 0;
417 raymove(curpos, cxset, sflags, r, scene);
418 return(r->ro != NULL & r->ro != &Aftplane);
419 }
420
421
422 static int
423 raymove(pos, cxs, dirf, r, cu) /* check for hit as we move */
424 FVECT pos; /* current position, modified herein */
425 OBJECT *cxs; /* checked objects, modified by checkhit */
426 int dirf; /* direction indicators to speed tests */
427 register RAY *r;
428 register CUBE *cu;
429 {
430 int ax;
431 double dt, t;
432
433 if (istree(cu->cutree)) { /* recurse on subcubes */
434 CUBE cukid;
435 register int br, sgn;
436
437 cukid.cusize = cu->cusize * 0.5; /* find subcube */
438 VCOPY(cukid.cuorg, cu->cuorg);
439 br = 0;
440 if (pos[0] >= cukid.cuorg[0]+cukid.cusize) {
441 cukid.cuorg[0] += cukid.cusize;
442 br |= 1;
443 }
444 if (pos[1] >= cukid.cuorg[1]+cukid.cusize) {
445 cukid.cuorg[1] += cukid.cusize;
446 br |= 2;
447 }
448 if (pos[2] >= cukid.cuorg[2]+cukid.cusize) {
449 cukid.cuorg[2] += cukid.cusize;
450 br |= 4;
451 }
452 for ( ; ; ) {
453 cukid.cutree = octkid(cu->cutree, br);
454 if ((ax = raymove(pos,cxs,dirf,r,&cukid)) == RAYHIT)
455 return(RAYHIT);
456 sgn = 1 << ax;
457 if (sgn & dirf) /* positive axis? */
458 if (sgn & br)
459 return(ax); /* overflow */
460 else {
461 cukid.cuorg[ax] += cukid.cusize;
462 br |= sgn;
463 }
464 else
465 if (sgn & br) {
466 cukid.cuorg[ax] -= cukid.cusize;
467 br &= ~sgn;
468 } else
469 return(ax); /* underflow */
470 }
471 /*NOTREACHED*/
472 }
473 if (isfull(cu->cutree)) {
474 if (checkhit(r, cu, cxs))
475 return(RAYHIT);
476 } else if (r->ro == &Aftplane && incube(cu, r->rop))
477 return(RAYHIT);
478 /* advance to next cube */
479 if (dirf&0x11) {
480 dt = dirf&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0];
481 t = (dt - pos[0])/r->rdir[0];
482 ax = 0;
483 } else
484 t = FHUGE;
485 if (dirf&0x22) {
486 dt = dirf&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1];
487 dt = (dt - pos[1])/r->rdir[1];
488 if (dt < t) {
489 t = dt;
490 ax = 1;
491 }
492 }
493 if (dirf&0x44) {
494 dt = dirf&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2];
495 dt = (dt - pos[2])/r->rdir[2];
496 if (dt < t) {
497 t = dt;
498 ax = 2;
499 }
500 }
501 pos[0] += r->rdir[0]*t;
502 pos[1] += r->rdir[1]*t;
503 pos[2] += r->rdir[2]*t;
504 return(ax);
505 }
506
507
508 static
509 checkhit(r, cu, cxs) /* check for hit in full cube */
510 register RAY *r;
511 CUBE *cu;
512 OBJECT *cxs;
513 {
514 OBJECT oset[MAXSET+1];
515 register OBJREC *o;
516 register int i;
517
518 objset(oset, cu->cutree);
519 checkset(oset, cxs); /* eliminate double-checking */
520 for (i = oset[0]; i > 0; i--) {
521 o = objptr(oset[i]);
522 (*ofun[o->otype].funp)(o, r);
523 }
524 if (r->ro == NULL)
525 return(0); /* no scores yet */
526
527 return(incube(cu, r->rop)); /* hit OK if in current cube */
528 }
529
530
531 static
532 checkset(os, cs) /* modify checked set and set to check */
533 register OBJECT *os; /* os' = os - cs */
534 register OBJECT *cs; /* cs' = cs + os */
535 {
536 OBJECT cset[MAXCSET+MAXSET+1];
537 register int i, j;
538 int k;
539 /* copy os in place, cset <- cs */
540 cset[0] = 0;
541 k = 0;
542 for (i = j = 1; i <= os[0]; i++) {
543 while (j <= cs[0] && cs[j] < os[i])
544 cset[++cset[0]] = cs[j++];
545 if (j > cs[0] || os[i] != cs[j]) { /* object to check */
546 os[++k] = os[i];
547 cset[++cset[0]] = os[i];
548 }
549 }
550 if (!(os[0] = k)) /* new "to check" set size */
551 return; /* special case */
552 while (j <= cs[0]) /* get the rest of cs */
553 cset[++cset[0]] = cs[j++];
554 if (cset[0] > MAXCSET) /* truncate "checked" set if nec. */
555 cset[0] = MAXCSET;
556 /* setcopy(cs, cset); */ /* copy cset back to cs */
557 os = cset;
558 for (i = os[0]; i-- >= 0; )
559 *cs++ = *os++;
560 }