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root/radiance/ray/src/rt/raytrace.c
Revision: 2.17
Committed: Wed Dec 21 09:10:23 1994 UTC (29 years, 4 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.16: +15 -11 lines
Log Message:
bug fixes from last change

File Contents

# Content
1 /* Copyright (c) 1994 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 objerror(r->ro, USER, "conflicting materials");
200 }
201 depth--; /* end here */
202 }
203
204
205 raymixture(r, fore, back, coef) /* mix modifiers */
206 register RAY *r;
207 OBJECT fore, back;
208 double coef;
209 {
210 RAY fr, br;
211 int foremat, backmat;
212 register int i;
213 /* clip coefficient */
214 if (coef > 1.0)
215 coef = 1.0;
216 else if (coef < 0.0)
217 coef = 0.0;
218 /* compute foreground and background */
219 foremat = backmat = -1;
220 /* foreground */
221 copystruct(&fr, r);
222 if (fore != OVOID && coef > FTINY)
223 foremat = rayshade(&fr, fore);
224 /* background */
225 copystruct(&br, r);
226 if (back != OVOID && coef < 1.0-FTINY)
227 backmat = rayshade(&br, back);
228 /* check */
229 if (foremat < 0)
230 if (backmat < 0)
231 foremat = backmat = 0;
232 else
233 foremat = backmat;
234 else if (backmat < 0)
235 backmat = foremat;
236 if ((foremat==0) != (backmat==0))
237 objerror(r->ro, USER, "mixing material with non-material");
238 /* mix perturbations */
239 for (i = 0; i < 3; i++)
240 r->pert[i] = coef*fr.pert[i] + (1.0-coef)*br.pert[i];
241 /* mix pattern colors */
242 scalecolor(fr.pcol, coef);
243 scalecolor(br.pcol, 1.0-coef);
244 copycolor(r->pcol, fr.pcol);
245 addcolor(r->pcol, br.pcol);
246 /* mix returned ray values */
247 if (foremat) {
248 scalecolor(fr.rcol, coef);
249 scalecolor(br.rcol, 1.0-coef);
250 copycolor(r->rcol, fr.rcol);
251 addcolor(r->rcol, br.rcol);
252 r->rt = bright(fr.rcol) > bright(br.rcol) ? fr.rt : br.rt;
253 }
254 /* return value tells if material */
255 return(foremat);
256 }
257
258
259 double
260 raynormal(norm, r) /* compute perturbed normal for ray */
261 FVECT norm;
262 register RAY *r;
263 {
264 double newdot;
265 register int i;
266
267 /* The perturbation is added to the surface normal to obtain
268 * the new normal. If the new normal would affect the surface
269 * orientation wrt. the ray, a correction is made. The method is
270 * still fraught with problems since reflected rays and similar
271 * directions calculated from the surface normal may spawn rays behind
272 * the surface. The only solution is to curb textures at high
273 * incidence (namely, keep DOT(rdir,pert) < Rdot).
274 */
275
276 for (i = 0; i < 3; i++)
277 norm[i] = r->ron[i] + r->pert[i];
278
279 if (normalize(norm) == 0.0) {
280 objerror(r->ro, WARNING, "illegal normal perturbation");
281 VCOPY(norm, r->ron);
282 return(r->rod);
283 }
284 newdot = -DOT(norm, r->rdir);
285 if ((newdot > 0.0) != (r->rod > 0.0)) { /* fix orientation */
286 for (i = 0; i < 3; i++)
287 norm[i] += 2.0*newdot*r->rdir[i];
288 newdot = -newdot;
289 }
290 return(newdot);
291 }
292
293
294 newrayxf(r) /* get new tranformation matrix for ray */
295 RAY *r;
296 {
297 static struct xfn {
298 struct xfn *next;
299 FULLXF xf;
300 } xfseed = { &xfseed }, *xflast = &xfseed;
301 register struct xfn *xp;
302 register RAY *rp;
303
304 /*
305 * Search for transform in circular list that
306 * has no associated ray in the tree.
307 */
308 xp = xflast;
309 for (rp = r->parent; rp != NULL; rp = rp->parent)
310 if (rp->rox == &xp->xf) { /* xp in use */
311 xp = xp->next; /* move to next */
312 if (xp == xflast) { /* need new one */
313 xp = (struct xfn *)bmalloc(sizeof(struct xfn));
314 if (xp == NULL)
315 error(SYSTEM,
316 "out of memory in newrayxf");
317 /* insert in list */
318 xp->next = xflast->next;
319 xflast->next = xp;
320 break; /* we're done */
321 }
322 rp = r; /* start check over */
323 }
324 /* got it */
325 r->rox = &xp->xf;
326 xflast = xp;
327 }
328
329
330 flipsurface(r) /* reverse surface orientation */
331 register RAY *r;
332 {
333 r->rod = -r->rod;
334 r->ron[0] = -r->ron[0];
335 r->ron[1] = -r->ron[1];
336 r->ron[2] = -r->ron[2];
337 r->pert[0] = -r->pert[0];
338 r->pert[1] = -r->pert[1];
339 r->pert[2] = -r->pert[2];
340 }
341
342
343 localhit(r, scene) /* check for hit in the octree */
344 register RAY *r;
345 register CUBE *scene;
346 {
347 OBJECT cxset[MAXCSET+1]; /* set of checked objects */
348 FVECT curpos; /* current cube position */
349 int sflags; /* sign flags */
350 double t, dt;
351 register int i;
352
353 nrays++; /* increment trace counter */
354 sflags = 0;
355 for (i = 0; i < 3; i++) {
356 curpos[i] = r->rorg[i];
357 if (r->rdir[i] > 1e-7)
358 sflags |= 1 << i;
359 else if (r->rdir[i] < -1e-7)
360 sflags |= 0x10 << i;
361 }
362 if (sflags == 0)
363 error(CONSISTENCY, "zero ray direction in localhit");
364 /* start off assuming nothing hit */
365 if (r->rmax > FTINY) { /* except aft plane if one */
366 r->ro = &Aftplane;
367 r->rot = r->rmax;
368 for (i = 0; i < 3; i++)
369 r->rop[i] = r->rorg[i] + r->rot*r->rdir[i];
370 }
371 /* find global cube entrance point */
372 t = 0.0;
373 if (!incube(scene, curpos)) {
374 /* find distance to entry */
375 for (i = 0; i < 3; i++) {
376 /* plane in our direction */
377 if (sflags & 1<<i)
378 dt = scene->cuorg[i];
379 else if (sflags & 0x10<<i)
380 dt = scene->cuorg[i] + scene->cusize;
381 else
382 continue;
383 /* distance to the plane */
384 dt = (dt - r->rorg[i])/r->rdir[i];
385 if (dt > t)
386 t = dt; /* farthest face is the one */
387 }
388 t += FTINY; /* fudge to get inside cube */
389 if (t >= r->rot) /* clipped already */
390 return(0);
391 /* advance position */
392 for (i = 0; i < 3; i++)
393 curpos[i] += r->rdir[i]*t;
394
395 if (!incube(scene, curpos)) /* non-intersecting ray */
396 return(0);
397 }
398 cxset[0] = 0;
399 return(raymove(curpos, cxset, sflags, r, scene) == RAYHIT &&
400 r->ro != &Aftplane);
401 }
402
403
404 static int
405 raymove(pos, cxs, dirf, r, cu) /* check for hit as we move */
406 FVECT pos; /* current position, modified herein */
407 OBJECT *cxs; /* checked objects, modified by checkhit */
408 int dirf; /* direction indicators to speed tests */
409 register RAY *r;
410 register CUBE *cu;
411 {
412 int ax;
413 double dt, t;
414
415 if (istree(cu->cutree)) { /* recurse on subcubes */
416 CUBE cukid;
417 register int br, sgn;
418
419 cukid.cusize = cu->cusize * 0.5; /* find subcube */
420 VCOPY(cukid.cuorg, cu->cuorg);
421 br = 0;
422 if (pos[0] >= cukid.cuorg[0]+cukid.cusize) {
423 cukid.cuorg[0] += cukid.cusize;
424 br |= 1;
425 }
426 if (pos[1] >= cukid.cuorg[1]+cukid.cusize) {
427 cukid.cuorg[1] += cukid.cusize;
428 br |= 2;
429 }
430 if (pos[2] >= cukid.cuorg[2]+cukid.cusize) {
431 cukid.cuorg[2] += cukid.cusize;
432 br |= 4;
433 }
434 for ( ; ; ) {
435 cukid.cutree = octkid(cu->cutree, br);
436 if ((ax = raymove(pos,cxs,dirf,r,&cukid)) == RAYHIT)
437 return(RAYHIT);
438 sgn = 1 << ax;
439 if (sgn & dirf) /* positive axis? */
440 if (sgn & br)
441 return(ax); /* overflow */
442 else {
443 cukid.cuorg[ax] += cukid.cusize;
444 br |= sgn;
445 }
446 else
447 if (sgn & br) {
448 cukid.cuorg[ax] -= cukid.cusize;
449 br &= ~sgn;
450 } else
451 return(ax); /* underflow */
452 }
453 /*NOTREACHED*/
454 }
455 if (isfull(cu->cutree) && checkhit(r, cu, cxs))
456 return(RAYHIT);
457 /* advance to next cube */
458 if (dirf&0x11) {
459 dt = dirf&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0];
460 t = (dt - pos[0])/r->rdir[0];
461 ax = 0;
462 } else
463 t = FHUGE;
464 if (dirf&0x22) {
465 dt = dirf&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1];
466 dt = (dt - pos[1])/r->rdir[1];
467 if (dt < t) {
468 t = dt;
469 ax = 1;
470 }
471 }
472 if (dirf&0x44) {
473 dt = dirf&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2];
474 dt = (dt - pos[2])/r->rdir[2];
475 if (dt < t) {
476 t = dt;
477 ax = 2;
478 }
479 }
480 pos[0] += r->rdir[0]*t;
481 pos[1] += r->rdir[1]*t;
482 pos[2] += r->rdir[2]*t;
483 return(ax);
484 }
485
486
487 static
488 checkhit(r, cu, cxs) /* check for hit in full cube */
489 register RAY *r;
490 CUBE *cu;
491 OBJECT *cxs;
492 {
493 OBJECT oset[MAXSET+1];
494 register OBJREC *o;
495 register int i;
496
497 objset(oset, cu->cutree);
498 checkset(oset, cxs); /* eliminate double-checking */
499 for (i = oset[0]; i > 0; i--) {
500 o = objptr(oset[i]);
501 (*ofun[o->otype].funp)(o, r);
502 }
503 if (r->ro == NULL)
504 return(0); /* no scores yet */
505
506 return(incube(cu, r->rop)); /* hit OK if in current cube */
507 }
508
509
510 static
511 checkset(os, cs) /* modify checked set and set to check */
512 register OBJECT *os; /* os' = os - cs */
513 register OBJECT *cs; /* cs' = cs + os */
514 {
515 OBJECT cset[MAXCSET+MAXSET+1];
516 register int i, j;
517 int k;
518 /* copy os in place, cset <- cs */
519 cset[0] = 0;
520 k = 0;
521 for (i = j = 1; i <= os[0]; i++) {
522 while (j <= cs[0] && cs[j] < os[i])
523 cset[++cset[0]] = cs[j++];
524 if (j > cs[0] || os[i] != cs[j]) { /* object to check */
525 os[++k] = os[i];
526 cset[++cset[0]] = os[i];
527 }
528 }
529 if (!(os[0] = k)) /* new "to check" set size */
530 return; /* special case */
531 while (j <= cs[0]) /* get the rest of cs */
532 cset[++cset[0]] = cs[j++];
533 if (cset[0] > MAXCSET) /* truncate "checked" set if nec. */
534 cset[0] = MAXCSET;
535 /* setcopy(cs, cset); */ /* copy cset back to cs */
536 os = cset;
537 for (i = os[0]; i-- >= 0; )
538 *cs++ = *os++;
539 }