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root/radiance/ray/src/rt/raytrace.c
Revision: 2.16
Committed: Tue Dec 20 20:18:22 1994 UTC (29 years, 4 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.15: +19 -4 lines
Log Message:
added -vo and -va (fore and aft clipping plane) view options

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