1 |
#ifndef lint |
2 |
static const char RCSid[] = "$Id: raytrace.c,v 2.43 2003/09/09 03:28:43 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 |
|
14 |
#include "otypes.h" |
15 |
|
16 |
#include "otspecial.h" |
17 |
|
18 |
#define MAXCSET ((MAXSET+1)*2-1) /* maximum check set size */ |
19 |
|
20 |
unsigned long raynum = 0; /* next unique ray number */ |
21 |
unsigned long 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 |
{0, 5, NULL, Lambfa}, NULL, |
27 |
}; /* a Lambertian surface */ |
28 |
|
29 |
OBJREC Aftplane; /* aft clipping plane object */ |
30 |
|
31 |
static int raymove(), checkhit(); |
32 |
static void checkset(); |
33 |
|
34 |
#define RAYHIT (-1) /* return value for intercepted ray */ |
35 |
|
36 |
|
37 |
int |
38 |
rayorigin(r, ro, rt, rw) /* start new ray from old one */ |
39 |
register RAY *r, *ro; |
40 |
int rt; |
41 |
double rw; |
42 |
{ |
43 |
double re; |
44 |
|
45 |
if ((r->parent = ro) == NULL) { /* primary ray */ |
46 |
r->rlvl = 0; |
47 |
r->rweight = rw; |
48 |
r->crtype = r->rtype = rt; |
49 |
r->rsrc = -1; |
50 |
r->clipset = NULL; |
51 |
r->revf = raytrace; |
52 |
copycolor(r->cext, cextinction); |
53 |
copycolor(r->albedo, salbedo); |
54 |
r->gecc = seccg; |
55 |
r->slights = NULL; |
56 |
} else { /* spawned ray */ |
57 |
r->rlvl = ro->rlvl; |
58 |
if (rt & RAYREFL) { |
59 |
r->rlvl++; |
60 |
r->rsrc = -1; |
61 |
r->clipset = ro->clipset; |
62 |
r->rmax = 0.0; |
63 |
} else { |
64 |
r->rsrc = ro->rsrc; |
65 |
r->clipset = ro->newcset; |
66 |
r->rmax = ro->rmax <= FTINY ? 0.0 : ro->rmax - ro->rot; |
67 |
} |
68 |
r->revf = ro->revf; |
69 |
copycolor(r->cext, ro->cext); |
70 |
copycolor(r->albedo, ro->albedo); |
71 |
r->gecc = ro->gecc; |
72 |
r->slights = ro->slights; |
73 |
r->crtype = ro->crtype | (r->rtype = rt); |
74 |
VCOPY(r->rorg, ro->rop); |
75 |
r->rweight = ro->rweight * rw; |
76 |
/* estimate absorption */ |
77 |
re = colval(ro->cext,RED) < colval(ro->cext,GRN) ? |
78 |
colval(ro->cext,RED) : colval(ro->cext,GRN); |
79 |
if (colval(ro->cext,BLU) < re) re = colval(ro->cext,BLU); |
80 |
if (re > 0.) |
81 |
r->rweight *= exp(-re*ro->rot); |
82 |
} |
83 |
rayclear(r); |
84 |
return(r->rlvl <= maxdepth && r->rweight >= minweight ? 0 : -1); |
85 |
} |
86 |
|
87 |
|
88 |
void |
89 |
rayclear(r) /* clear a ray for (re)evaluation */ |
90 |
register RAY *r; |
91 |
{ |
92 |
r->rno = raynum++; |
93 |
r->newcset = r->clipset; |
94 |
r->hitf = rayhit; |
95 |
r->robj = OVOID; |
96 |
r->ro = NULL; |
97 |
r->rox = NULL; |
98 |
r->rt = r->rot = FHUGE; |
99 |
r->pert[0] = r->pert[1] = r->pert[2] = 0.0; |
100 |
r->uv[0] = r->uv[1] = 0.0; |
101 |
setcolor(r->pcol, 1.0, 1.0, 1.0); |
102 |
setcolor(r->rcol, 0.0, 0.0, 0.0); |
103 |
} |
104 |
|
105 |
|
106 |
void |
107 |
raytrace(r) /* trace a ray and compute its value */ |
108 |
RAY *r; |
109 |
{ |
110 |
if (localhit(r, &thescene)) |
111 |
raycont(r); /* hit local surface, evaluate */ |
112 |
else if (r->ro == &Aftplane) { |
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r->ro = NULL; /* hit aft clipping plane */ |
114 |
r->rot = FHUGE; |
115 |
} else if (sourcehit(r)) |
116 |
rayshade(r, r->ro->omod); /* distant source */ |
117 |
|
118 |
rayparticipate(r); /* for participating medium */ |
119 |
|
120 |
if (trace != NULL) |
121 |
(*trace)(r); /* trace execution */ |
122 |
} |
123 |
|
124 |
|
125 |
void |
126 |
raycont(r) /* check for clipped object and continue */ |
127 |
register RAY *r; |
128 |
{ |
129 |
if ((r->clipset != NULL && inset(r->clipset, r->ro->omod)) || |
130 |
!rayshade(r, r->ro->omod)) |
131 |
raytrans(r); |
132 |
} |
133 |
|
134 |
|
135 |
void |
136 |
raytrans(r) /* transmit ray as is */ |
137 |
register RAY *r; |
138 |
{ |
139 |
RAY tr; |
140 |
|
141 |
if (rayorigin(&tr, r, TRANS, 1.0) == 0) { |
142 |
VCOPY(tr.rdir, r->rdir); |
143 |
rayvalue(&tr); |
144 |
copycolor(r->rcol, tr.rcol); |
145 |
r->rt = r->rot + tr.rt; |
146 |
} |
147 |
} |
148 |
|
149 |
|
150 |
int |
151 |
rayshade(r, mod) /* shade ray r with material mod */ |
152 |
register RAY *r; |
153 |
int mod; |
154 |
{ |
155 |
int gotmat; |
156 |
register OBJREC *m; |
157 |
r->rt = r->rot; /* set effective ray length */ |
158 |
for (gotmat = 0; !gotmat && mod != OVOID; mod = m->omod) { |
159 |
m = objptr(mod); |
160 |
/****** unnecessary test since modifier() is always called |
161 |
if (!ismodifier(m->otype)) { |
162 |
sprintf(errmsg, "illegal modifier \"%s\"", m->oname); |
163 |
error(USER, errmsg); |
164 |
} |
165 |
******/ |
166 |
/* hack for irradiance calculation */ |
167 |
if (do_irrad && !(r->crtype & ~(PRIMARY|TRANS)) && |
168 |
m->otype != MAT_CLIP && |
169 |
(ofun[m->otype].flags & (T_M|T_X))) { |
170 |
if (irr_ignore(m->otype)) { |
171 |
raytrans(r); |
172 |
return(1); |
173 |
} |
174 |
if (!islight(m->otype)) |
175 |
m = &Lamb; |
176 |
} |
177 |
/* materials call raytexture */ |
178 |
gotmat = (*ofun[m->otype].funp)(m, r); |
179 |
} |
180 |
return(gotmat); |
181 |
} |
182 |
|
183 |
|
184 |
void |
185 |
rayparticipate(r) /* compute ray medium participation */ |
186 |
register RAY *r; |
187 |
{ |
188 |
COLOR ce, ca; |
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double re, ge, be; |
190 |
|
191 |
if (intens(r->cext) <= 1./FHUGE) |
192 |
return; /* no medium */ |
193 |
re = r->rot*colval(r->cext,RED); |
194 |
ge = r->rot*colval(r->cext,GRN); |
195 |
be = r->rot*colval(r->cext,BLU); |
196 |
if (r->crtype & SHADOW) { /* no scattering for sources */ |
197 |
re *= 1. - colval(r->albedo,RED); |
198 |
ge *= 1. - colval(r->albedo,GRN); |
199 |
be *= 1. - colval(r->albedo,BLU); |
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} |
201 |
setcolor(ce, re<=0. ? 1. : re>92. ? 0. : exp(-re), |
202 |
ge<=0. ? 1. : ge>92. ? 0. : exp(-ge), |
203 |
be<=0. ? 1. : be>92. ? 0. : exp(-be)); |
204 |
multcolor(r->rcol, ce); /* path absorption */ |
205 |
if (r->crtype & SHADOW || intens(r->albedo) <= FTINY) |
206 |
return; /* no scattering */ |
207 |
setcolor(ca, |
208 |
colval(r->albedo,RED)*colval(ambval,RED)*(1.-colval(ce,RED)), |
209 |
colval(r->albedo,GRN)*colval(ambval,GRN)*(1.-colval(ce,GRN)), |
210 |
colval(r->albedo,BLU)*colval(ambval,BLU)*(1.-colval(ce,BLU))); |
211 |
addcolor(r->rcol, ca); /* ambient in scattering */ |
212 |
srcscatter(r); /* source in scattering */ |
213 |
} |
214 |
|
215 |
|
216 |
void |
217 |
raytexture(r, mod) /* get material modifiers */ |
218 |
RAY *r; |
219 |
OBJECT mod; |
220 |
{ |
221 |
register OBJREC *m; |
222 |
/* execute textures and patterns */ |
223 |
for ( ; mod != OVOID; mod = m->omod) { |
224 |
m = objptr(mod); |
225 |
/****** unnecessary test since modifier() is always called |
226 |
if (!ismodifier(m->otype)) { |
227 |
sprintf(errmsg, "illegal modifier \"%s\"", m->oname); |
228 |
error(USER, errmsg); |
229 |
} |
230 |
******/ |
231 |
if ((*ofun[m->otype].funp)(m, r)) { |
232 |
sprintf(errmsg, "conflicting material \"%s\"", |
233 |
m->oname); |
234 |
objerror(r->ro, USER, errmsg); |
235 |
} |
236 |
} |
237 |
} |
238 |
|
239 |
|
240 |
int |
241 |
raymixture(r, fore, back, coef) /* mix modifiers */ |
242 |
register RAY *r; |
243 |
OBJECT fore, back; |
244 |
double coef; |
245 |
{ |
246 |
RAY fr, br; |
247 |
int foremat, backmat; |
248 |
register int i; |
249 |
/* bound coefficient */ |
250 |
if (coef > 1.0) |
251 |
coef = 1.0; |
252 |
else if (coef < 0.0) |
253 |
coef = 0.0; |
254 |
/* compute foreground and background */ |
255 |
foremat = backmat = 0; |
256 |
/* foreground */ |
257 |
fr = *r; |
258 |
if (coef > FTINY) |
259 |
foremat = rayshade(&fr, fore); |
260 |
/* background */ |
261 |
br = *r; |
262 |
if (coef < 1.0-FTINY) |
263 |
backmat = rayshade(&br, back); |
264 |
/* check for transparency */ |
265 |
if (backmat ^ foremat) { |
266 |
if (backmat && coef > FTINY) |
267 |
raytrans(&fr); |
268 |
else if (foremat && coef < 1.0-FTINY) |
269 |
raytrans(&br); |
270 |
} |
271 |
/* mix perturbations */ |
272 |
for (i = 0; i < 3; i++) |
273 |
r->pert[i] = coef*fr.pert[i] + (1.0-coef)*br.pert[i]; |
274 |
/* mix pattern colors */ |
275 |
scalecolor(fr.pcol, coef); |
276 |
scalecolor(br.pcol, 1.0-coef); |
277 |
copycolor(r->pcol, fr.pcol); |
278 |
addcolor(r->pcol, br.pcol); |
279 |
/* return value tells if material */ |
280 |
if (!foremat & !backmat) |
281 |
return(0); |
282 |
/* mix returned ray values */ |
283 |
scalecolor(fr.rcol, coef); |
284 |
scalecolor(br.rcol, 1.0-coef); |
285 |
copycolor(r->rcol, fr.rcol); |
286 |
addcolor(r->rcol, br.rcol); |
287 |
r->rt = bright(fr.rcol) > bright(br.rcol) ? fr.rt : br.rt; |
288 |
return(1); |
289 |
} |
290 |
|
291 |
|
292 |
double |
293 |
raydist(r, flags) /* compute (cumulative) ray distance */ |
294 |
register RAY *r; |
295 |
register int flags; |
296 |
{ |
297 |
double sum = 0.0; |
298 |
|
299 |
while (r != NULL && r->crtype&flags) { |
300 |
sum += r->rot; |
301 |
r = r->parent; |
302 |
} |
303 |
return(sum); |
304 |
} |
305 |
|
306 |
|
307 |
double |
308 |
raynormal(norm, r) /* compute perturbed normal for ray */ |
309 |
FVECT norm; |
310 |
register RAY *r; |
311 |
{ |
312 |
double newdot; |
313 |
register int i; |
314 |
|
315 |
/* The perturbation is added to the surface normal to obtain |
316 |
* the new normal. If the new normal would affect the surface |
317 |
* orientation wrt. the ray, a correction is made. The method is |
318 |
* still fraught with problems since reflected rays and similar |
319 |
* directions calculated from the surface normal may spawn rays behind |
320 |
* the surface. The only solution is to curb textures at high |
321 |
* incidence (namely, keep DOT(rdir,pert) < Rdot). |
322 |
*/ |
323 |
|
324 |
for (i = 0; i < 3; i++) |
325 |
norm[i] = r->ron[i] + r->pert[i]; |
326 |
|
327 |
if (normalize(norm) == 0.0) { |
328 |
objerror(r->ro, WARNING, "illegal normal perturbation"); |
329 |
VCOPY(norm, r->ron); |
330 |
return(r->rod); |
331 |
} |
332 |
newdot = -DOT(norm, r->rdir); |
333 |
if ((newdot > 0.0) != (r->rod > 0.0)) { /* fix orientation */ |
334 |
for (i = 0; i < 3; i++) |
335 |
norm[i] += 2.0*newdot*r->rdir[i]; |
336 |
newdot = -newdot; |
337 |
} |
338 |
return(newdot); |
339 |
} |
340 |
|
341 |
|
342 |
void |
343 |
newrayxf(r) /* get new tranformation matrix for ray */ |
344 |
RAY *r; |
345 |
{ |
346 |
static struct xfn { |
347 |
struct xfn *next; |
348 |
FULLXF xf; |
349 |
} xfseed = { &xfseed }, *xflast = &xfseed; |
350 |
register struct xfn *xp; |
351 |
register RAY *rp; |
352 |
|
353 |
/* |
354 |
* Search for transform in circular list that |
355 |
* has no associated ray in the tree. |
356 |
*/ |
357 |
xp = xflast; |
358 |
for (rp = r->parent; rp != NULL; rp = rp->parent) |
359 |
if (rp->rox == &xp->xf) { /* xp in use */ |
360 |
xp = xp->next; /* move to next */ |
361 |
if (xp == xflast) { /* need new one */ |
362 |
xp = (struct xfn *)malloc(sizeof(struct xfn)); |
363 |
if (xp == NULL) |
364 |
error(SYSTEM, |
365 |
"out of memory in newrayxf"); |
366 |
/* insert in list */ |
367 |
xp->next = xflast->next; |
368 |
xflast->next = xp; |
369 |
break; /* we're done */ |
370 |
} |
371 |
rp = r; /* start check over */ |
372 |
} |
373 |
/* got it */ |
374 |
r->rox = &xp->xf; |
375 |
xflast = xp; |
376 |
} |
377 |
|
378 |
|
379 |
void |
380 |
flipsurface(r) /* reverse surface orientation */ |
381 |
register RAY *r; |
382 |
{ |
383 |
r->rod = -r->rod; |
384 |
r->ron[0] = -r->ron[0]; |
385 |
r->ron[1] = -r->ron[1]; |
386 |
r->ron[2] = -r->ron[2]; |
387 |
r->pert[0] = -r->pert[0]; |
388 |
r->pert[1] = -r->pert[1]; |
389 |
r->pert[2] = -r->pert[2]; |
390 |
} |
391 |
|
392 |
|
393 |
void |
394 |
rayhit(oset, r) /* standard ray hit test */ |
395 |
OBJECT *oset; |
396 |
RAY *r; |
397 |
{ |
398 |
OBJREC *o; |
399 |
int i; |
400 |
|
401 |
for (i = oset[0]; i > 0; i--) { |
402 |
o = objptr(oset[i]); |
403 |
if ((*ofun[o->otype].funp)(o, r)) |
404 |
r->robj = oset[i]; |
405 |
} |
406 |
} |
407 |
|
408 |
|
409 |
int |
410 |
localhit(r, scene) /* check for hit in the octree */ |
411 |
register RAY *r; |
412 |
register CUBE *scene; |
413 |
{ |
414 |
OBJECT cxset[MAXCSET+1]; /* set of checked objects */ |
415 |
FVECT curpos; /* current cube position */ |
416 |
int sflags; /* sign flags */ |
417 |
double t, dt; |
418 |
register int i; |
419 |
|
420 |
nrays++; /* increment trace counter */ |
421 |
sflags = 0; |
422 |
for (i = 0; i < 3; i++) { |
423 |
curpos[i] = r->rorg[i]; |
424 |
if (r->rdir[i] > 1e-7) |
425 |
sflags |= 1 << i; |
426 |
else if (r->rdir[i] < -1e-7) |
427 |
sflags |= 0x10 << i; |
428 |
} |
429 |
if (sflags == 0) |
430 |
error(CONSISTENCY, "zero ray direction in localhit"); |
431 |
/* start off assuming nothing hit */ |
432 |
if (r->rmax > FTINY) { /* except aft plane if one */ |
433 |
r->ro = &Aftplane; |
434 |
r->rot = r->rmax; |
435 |
for (i = 0; i < 3; i++) |
436 |
r->rop[i] = r->rorg[i] + r->rot*r->rdir[i]; |
437 |
} |
438 |
/* find global cube entrance point */ |
439 |
t = 0.0; |
440 |
if (!incube(scene, curpos)) { |
441 |
/* find distance to entry */ |
442 |
for (i = 0; i < 3; i++) { |
443 |
/* plane in our direction */ |
444 |
if (sflags & 1<<i) |
445 |
dt = scene->cuorg[i]; |
446 |
else if (sflags & 0x10<<i) |
447 |
dt = scene->cuorg[i] + scene->cusize; |
448 |
else |
449 |
continue; |
450 |
/* distance to the plane */ |
451 |
dt = (dt - r->rorg[i])/r->rdir[i]; |
452 |
if (dt > t) |
453 |
t = dt; /* farthest face is the one */ |
454 |
} |
455 |
t += FTINY; /* fudge to get inside cube */ |
456 |
if (t >= r->rot) /* clipped already */ |
457 |
return(0); |
458 |
/* advance position */ |
459 |
for (i = 0; i < 3; i++) |
460 |
curpos[i] += r->rdir[i]*t; |
461 |
|
462 |
if (!incube(scene, curpos)) /* non-intersecting ray */ |
463 |
return(0); |
464 |
} |
465 |
cxset[0] = 0; |
466 |
raymove(curpos, cxset, sflags, r, scene); |
467 |
return((r->ro != NULL) & (r->ro != &Aftplane)); |
468 |
} |
469 |
|
470 |
|
471 |
static int |
472 |
raymove(pos, cxs, dirf, r, cu) /* check for hit as we move */ |
473 |
FVECT pos; /* current position, modified herein */ |
474 |
OBJECT *cxs; /* checked objects, modified by checkhit */ |
475 |
int dirf; /* direction indicators to speed tests */ |
476 |
register RAY *r; |
477 |
register CUBE *cu; |
478 |
{ |
479 |
int ax; |
480 |
double dt, t; |
481 |
|
482 |
if (istree(cu->cutree)) { /* recurse on subcubes */ |
483 |
CUBE cukid; |
484 |
register int br, sgn; |
485 |
|
486 |
cukid.cusize = cu->cusize * 0.5; /* find subcube */ |
487 |
VCOPY(cukid.cuorg, cu->cuorg); |
488 |
br = 0; |
489 |
if (pos[0] >= cukid.cuorg[0]+cukid.cusize) { |
490 |
cukid.cuorg[0] += cukid.cusize; |
491 |
br |= 1; |
492 |
} |
493 |
if (pos[1] >= cukid.cuorg[1]+cukid.cusize) { |
494 |
cukid.cuorg[1] += cukid.cusize; |
495 |
br |= 2; |
496 |
} |
497 |
if (pos[2] >= cukid.cuorg[2]+cukid.cusize) { |
498 |
cukid.cuorg[2] += cukid.cusize; |
499 |
br |= 4; |
500 |
} |
501 |
for ( ; ; ) { |
502 |
cukid.cutree = octkid(cu->cutree, br); |
503 |
if ((ax = raymove(pos,cxs,dirf,r,&cukid)) == RAYHIT) |
504 |
return(RAYHIT); |
505 |
sgn = 1 << ax; |
506 |
if (sgn & dirf) /* positive axis? */ |
507 |
if (sgn & br) |
508 |
return(ax); /* overflow */ |
509 |
else { |
510 |
cukid.cuorg[ax] += cukid.cusize; |
511 |
br |= sgn; |
512 |
} |
513 |
else |
514 |
if (sgn & br) { |
515 |
cukid.cuorg[ax] -= cukid.cusize; |
516 |
br &= ~sgn; |
517 |
} else |
518 |
return(ax); /* underflow */ |
519 |
} |
520 |
/*NOTREACHED*/ |
521 |
} |
522 |
if (isfull(cu->cutree)) { |
523 |
if (checkhit(r, cu, cxs)) |
524 |
return(RAYHIT); |
525 |
} else if (r->ro == &Aftplane && incube(cu, r->rop)) |
526 |
return(RAYHIT); |
527 |
/* advance to next cube */ |
528 |
if (dirf&0x11) { |
529 |
dt = dirf&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0]; |
530 |
t = (dt - pos[0])/r->rdir[0]; |
531 |
ax = 0; |
532 |
} else |
533 |
t = FHUGE; |
534 |
if (dirf&0x22) { |
535 |
dt = dirf&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1]; |
536 |
dt = (dt - pos[1])/r->rdir[1]; |
537 |
if (dt < t) { |
538 |
t = dt; |
539 |
ax = 1; |
540 |
} |
541 |
} |
542 |
if (dirf&0x44) { |
543 |
dt = dirf&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2]; |
544 |
dt = (dt - pos[2])/r->rdir[2]; |
545 |
if (dt < t) { |
546 |
t = dt; |
547 |
ax = 2; |
548 |
} |
549 |
} |
550 |
pos[0] += r->rdir[0]*t; |
551 |
pos[1] += r->rdir[1]*t; |
552 |
pos[2] += r->rdir[2]*t; |
553 |
return(ax); |
554 |
} |
555 |
|
556 |
|
557 |
static int |
558 |
checkhit(r, cu, cxs) /* check for hit in full cube */ |
559 |
register RAY *r; |
560 |
CUBE *cu; |
561 |
OBJECT *cxs; |
562 |
{ |
563 |
OBJECT oset[MAXSET+1]; |
564 |
|
565 |
objset(oset, cu->cutree); |
566 |
checkset(oset, cxs); /* avoid double-checking */ |
567 |
|
568 |
(*r->hitf)(oset, r); /* test for hit in set */ |
569 |
|
570 |
if (r->robj == OVOID) |
571 |
return(0); /* no scores yet */ |
572 |
|
573 |
return(incube(cu, r->rop)); /* hit OK if in current cube */ |
574 |
} |
575 |
|
576 |
|
577 |
static void |
578 |
checkset(os, cs) /* modify checked set and set to check */ |
579 |
register OBJECT *os; /* os' = os - cs */ |
580 |
register OBJECT *cs; /* cs' = cs + os */ |
581 |
{ |
582 |
OBJECT cset[MAXCSET+MAXSET+1]; |
583 |
register int i, j; |
584 |
int k; |
585 |
/* copy os in place, cset <- cs */ |
586 |
cset[0] = 0; |
587 |
k = 0; |
588 |
for (i = j = 1; i <= os[0]; i++) { |
589 |
while (j <= cs[0] && cs[j] < os[i]) |
590 |
cset[++cset[0]] = cs[j++]; |
591 |
if (j > cs[0] || os[i] != cs[j]) { /* object to check */ |
592 |
os[++k] = os[i]; |
593 |
cset[++cset[0]] = os[i]; |
594 |
} |
595 |
} |
596 |
if (!(os[0] = k)) /* new "to check" set size */ |
597 |
return; /* special case */ |
598 |
while (j <= cs[0]) /* get the rest of cs */ |
599 |
cset[++cset[0]] = cs[j++]; |
600 |
if (cset[0] > MAXCSET) /* truncate "checked" set if nec. */ |
601 |
cset[0] = MAXCSET; |
602 |
/* setcopy(cs, cset); */ /* copy cset back to cs */ |
603 |
os = cset; |
604 |
for (i = os[0]; i-- >= 0; ) |
605 |
*cs++ = *os++; |
606 |
} |