--- ray/src/rt/raytrace.c 1990/01/02 15:16:14 1.8
+++ ray/src/rt/raytrace.c 2003/02/22 02:07:29 2.34
@@ -1,91 +1,195 @@
-/* Copyright (c) 1986 Regents of the University of California */
-
#ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char RCSid[] = "$Id: raytrace.c,v 2.34 2003/02/22 02:07:29 greg Exp $";
#endif
-
/*
* raytrace.c - routines for tracing and shading rays.
*
- * 8/7/85
+ * External symbols declared in ray.h
*/
+/* ====================================================================
+ * The Radiance Software License, Version 1.0
+ *
+ * Copyright (c) 1990 - 2002 The Regents of the University of California,
+ * through Lawrence Berkeley National Laboratory. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * 3. The end-user documentation included with the redistribution,
+ * if any, must include the following acknowledgment:
+ * "This product includes Radiance software
+ * (http://radsite.lbl.gov/)
+ * developed by the Lawrence Berkeley National Laboratory
+ * (http://www.lbl.gov/)."
+ * Alternately, this acknowledgment may appear in the software itself,
+ * if and wherever such third-party acknowledgments normally appear.
+ *
+ * 4. The names "Radiance," "Lawrence Berkeley National Laboratory"
+ * and "The Regents of the University of California" must
+ * not be used to endorse or promote products derived from this
+ * software without prior written permission. For written
+ * permission, please contact radiance@radsite.lbl.gov.
+ *
+ * 5. Products derived from this software may not be called "Radiance",
+ * nor may "Radiance" appear in their name, without prior written
+ * permission of Lawrence Berkeley National Laboratory.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of Lawrence Berkeley National Laboratory. For more
+ * information on Lawrence Berkeley National Laboratory, please see
+ * .
+ */
+
#include "ray.h"
-#include "octree.h"
-
#include "otypes.h"
-extern CUBE thescene; /* our scene */
-extern int maxdepth; /* maximum recursion depth */
-extern double minweight; /* minimum ray weight */
+#include "otspecial.h"
-long nrays = 0L; /* number of rays traced */
+#define MAXCSET ((MAXSET+1)*2-1) /* maximum check set size */
-#define MAXLOOP 128 /* modifier loop detection */
+unsigned long raynum = 0; /* next unique ray number */
+unsigned long nrays = 0; /* number of calls to localhit */
+static FLOAT Lambfa[5] = {PI, PI, PI, 0.0, 0.0};
+OBJREC Lamb = {
+ OVOID, MAT_PLASTIC, "Lambertian",
+ {0, 5, NULL, Lambfa}, NULL,
+}; /* a Lambertian surface */
+
+OBJREC Aftplane; /* aft clipping plane object */
+
+static int raymove(), checkhit();
+static void checkset();
+
+#ifndef MAXLOOP
+#define MAXLOOP 0 /* modifier loop detection */
+#endif
+
#define RAYHIT (-1) /* return value for intercepted ray */
+int
rayorigin(r, ro, rt, rw) /* start new ray from old one */
register RAY *r, *ro;
int rt;
double rw;
{
+ double re;
+
if ((r->parent = ro) == NULL) { /* primary ray */
r->rlvl = 0;
r->rweight = rw;
r->crtype = r->rtype = rt;
r->rsrc = -1;
r->clipset = NULL;
+ r->revf = raytrace;
+ copycolor(r->cext, cextinction);
+ copycolor(r->albedo, salbedo);
+ r->gecc = seccg;
+ r->slights = NULL;
} else { /* spawned ray */
r->rlvl = ro->rlvl;
if (rt & RAYREFL) {
r->rlvl++;
r->rsrc = -1;
r->clipset = ro->clipset;
+ r->rmax = 0.0;
} else {
r->rsrc = ro->rsrc;
r->clipset = ro->newcset;
+ r->rmax = ro->rmax <= FTINY ? 0.0 : ro->rmax - ro->rot;
}
- r->rweight = ro->rweight * rw;
+ r->revf = ro->revf;
+ copycolor(r->cext, ro->cext);
+ copycolor(r->albedo, ro->albedo);
+ r->gecc = ro->gecc;
+ r->slights = ro->slights;
r->crtype = ro->crtype | (r->rtype = rt);
VCOPY(r->rorg, ro->rop);
+ r->rweight = ro->rweight * rw;
+ /* estimate absorption */
+ re = colval(ro->cext,RED) < colval(ro->cext,GRN) ?
+ colval(ro->cext,RED) : colval(ro->cext,GRN);
+ if (colval(ro->cext,BLU) < re) re = colval(ro->cext,BLU);
+ if (re > 0.)
+ r->rweight *= exp(-re*ro->rot);
}
- r->rno = nrays;
+ rayclear(r);
+ return(r->rlvl <= maxdepth && r->rweight >= minweight ? 0 : -1);
+}
+
+
+void
+rayclear(r) /* clear a ray for (re)evaluation */
+register RAY *r;
+{
+ r->rno = raynum++;
r->newcset = r->clipset;
+ r->robj = OVOID;
r->ro = NULL;
- r->rot = FHUGE;
+ r->rox = NULL;
+ r->rt = r->rot = FHUGE;
r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
setcolor(r->pcol, 1.0, 1.0, 1.0);
setcolor(r->rcol, 0.0, 0.0, 0.0);
- return(r->rlvl <= maxdepth && r->rweight >= minweight ? 0 : -1);
}
-rayvalue(r) /* compute a ray's value */
+void
+raytrace(r) /* trace a ray and compute its value */
RAY *r;
{
- extern int (*trace)();
+ if (localhit(r, &thescene))
+ raycont(r); /* hit local surface, evaluate */
+ else if (r->ro == &Aftplane) {
+ r->ro = NULL; /* hit aft clipping plane */
+ r->rot = FHUGE;
+ } else if (sourcehit(r))
+ rayshade(r, r->ro->omod); /* distant source */
- if (localhit(r, &thescene) || sourcehit(r))
- raycont(r);
+ rayparticipate(r); /* for participating medium */
if (trace != NULL)
(*trace)(r); /* trace execution */
}
+void
raycont(r) /* check for clipped object and continue */
register RAY *r;
{
- if (r->clipset != NULL && inset(r->clipset, r->ro->omod))
+ if ((r->clipset != NULL && inset(r->clipset, r->ro->omod)) ||
+ !rayshade(r, r->ro->omod))
raytrans(r);
- else
- rayshade(r, r->ro->omod);
}
+void
raytrans(r) /* transmit ray as is */
register RAY *r;
{
@@ -95,20 +199,26 @@ register RAY *r;
VCOPY(tr.rdir, r->rdir);
rayvalue(&tr);
copycolor(r->rcol, tr.rcol);
+ r->rt = r->rot + tr.rt;
}
}
+int
rayshade(r, mod) /* shade ray r with material mod */
register RAY *r;
int mod;
{
- static int depth = 0;
+ int gotmat;
register OBJREC *m;
+#if MAXLOOP
+ static int depth = 0;
/* check for infinite loop */
if (depth++ >= MAXLOOP)
objerror(r->ro, USER, "possible modifier loop");
- for ( ; mod != OVOID; mod = m->omod) {
+#endif
+ r->rt = r->rot; /* set effective ray length */
+ for (gotmat = 0; !gotmat && mod != OVOID; mod = m->omod) {
m = objptr(mod);
/****** unnecessary test since modifier() is always called
if (!ismodifier(m->otype)) {
@@ -116,87 +226,159 @@ int mod;
error(USER, errmsg);
}
******/
- (*ofun[m->otype].funp)(m, r); /* execute function */
- m->lastrno = r->rno;
- if (ismaterial(m->otype)) { /* materials call raytexture */
- depth--;
- return; /* we're done */
+ /* hack for irradiance calculation */
+ if (do_irrad && !(r->crtype & ~(PRIMARY|TRANS))) {
+ if (irr_ignore(m->otype)) {
+#if MAXLOOP
+ depth--;
+#endif
+ raytrans(r);
+ return(1);
+ }
+ if (!islight(m->otype))
+ m = &Lamb;
}
+ /* materials call raytexture */
+ gotmat = (*ofun[m->otype].funp)(m, r);
}
- objerror(r->ro, USER, "material not found");
+#if MAXLOOP
+ depth--;
+#endif
+ return(gotmat);
}
+void
+rayparticipate(r) /* compute ray medium participation */
+register RAY *r;
+{
+ COLOR ce, ca;
+ double re, ge, be;
+
+ if (intens(r->cext) <= 1./FHUGE)
+ return; /* no medium */
+ re = r->rot*colval(r->cext,RED);
+ ge = r->rot*colval(r->cext,GRN);
+ be = r->rot*colval(r->cext,BLU);
+ if (r->crtype & SHADOW) { /* no scattering for sources */
+ re *= 1. - colval(r->albedo,RED);
+ ge *= 1. - colval(r->albedo,GRN);
+ be *= 1. - colval(r->albedo,BLU);
+ }
+ setcolor(ce, re<=0. ? 1. : re>92. ? 0. : exp(-re),
+ ge<=0. ? 1. : ge>92. ? 0. : exp(-ge),
+ be<=0. ? 1. : be>92. ? 0. : exp(-be));
+ multcolor(r->rcol, ce); /* path absorption */
+ if (r->crtype & SHADOW || intens(r->albedo) <= FTINY)
+ return; /* no scattering */
+ setcolor(ca,
+ colval(r->albedo,RED)*colval(ambval,RED)*(1.-colval(ce,RED)),
+ colval(r->albedo,GRN)*colval(ambval,GRN)*(1.-colval(ce,GRN)),
+ colval(r->albedo,BLU)*colval(ambval,BLU)*(1.-colval(ce,BLU)));
+ addcolor(r->rcol, ca); /* ambient in scattering */
+ srcscatter(r); /* source in scattering */
+}
+
+
raytexture(r, mod) /* get material modifiers */
RAY *r;
int mod;
{
- static int depth = 0;
register OBJREC *m;
+#if MAXLOOP
+ static int depth = 0;
/* check for infinite loop */
if (depth++ >= MAXLOOP)
objerror(r->ro, USER, "modifier loop");
+#endif
/* execute textures and patterns */
for ( ; mod != OVOID; mod = m->omod) {
m = objptr(mod);
- if (!istexture(m->otype)) {
+ /****** unnecessary test since modifier() is always called
+ if (!ismodifier(m->otype)) {
sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
error(USER, errmsg);
}
- (*ofun[m->otype].funp)(m, r);
- m->lastrno = r->rno;
+ ******/
+ if ((*ofun[m->otype].funp)(m, r)) {
+ sprintf(errmsg, "conflicting material \"%s\"",
+ m->oname);
+ objerror(r->ro, USER, errmsg);
+ }
}
+#if MAXLOOP
depth--; /* end here */
+#endif
}
+int
raymixture(r, fore, back, coef) /* mix modifiers */
register RAY *r;
OBJECT fore, back;
double coef;
{
- FVECT curpert, forepert, backpert;
- COLOR curpcol, forepcol, backpcol;
+ RAY fr, br;
+ int foremat, backmat;
register int i;
- /* clip coefficient */
+ /* bound coefficient */
if (coef > 1.0)
coef = 1.0;
else if (coef < 0.0)
coef = 0.0;
- /* save current mods */
- VCOPY(curpert, r->pert);
- copycolor(curpcol, r->pcol);
- /* compute new mods */
- /* foreground */
- r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
- setcolor(r->pcol, 1.0, 1.0, 1.0);
- if (fore != OVOID && coef > FTINY)
- raytexture(r, fore);
- VCOPY(forepert, r->pert);
- copycolor(forepcol, r->pcol);
- /* background */
- r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
- setcolor(r->pcol, 1.0, 1.0, 1.0);
- if (back != OVOID && coef < 1.0-FTINY)
- raytexture(r, back);
- VCOPY(backpert, r->pert);
- copycolor(backpcol, r->pcol);
- /* sum perturbations */
+ /* compute foreground and background */
+ foremat = backmat = 0;
+ /* foreground */
+ copystruct(&fr, r);
+ if (coef > FTINY)
+ foremat = rayshade(&fr, fore);
+ /* background */
+ copystruct(&br, r);
+ if (coef < 1.0-FTINY)
+ backmat = rayshade(&br, back);
+ /* check for transparency */
+ if (backmat ^ foremat)
+ if (backmat && coef > FTINY)
+ raytrans(&fr);
+ else if (foremat && coef < 1.0-FTINY)
+ raytrans(&br);
+ /* mix perturbations */
for (i = 0; i < 3; i++)
- r->pert[i] = curpert[i] + coef*forepert[i] +
- (1.0-coef)*backpert[i];
- /* multiply colors */
- setcolor(r->pcol, coef*colval(forepcol,RED) +
- (1.0-coef)*colval(backpcol,RED),
- coef*colval(forepcol,GRN) +
- (1.0-coef)*colval(backpcol,GRN),
- coef*colval(forepcol,BLU) +
- (1.0-coef)*colval(backpcol,BLU));
- multcolor(r->pcol, curpcol);
+ r->pert[i] = coef*fr.pert[i] + (1.0-coef)*br.pert[i];
+ /* mix pattern colors */
+ scalecolor(fr.pcol, coef);
+ scalecolor(br.pcol, 1.0-coef);
+ copycolor(r->pcol, fr.pcol);
+ addcolor(r->pcol, br.pcol);
+ /* return value tells if material */
+ if (!foremat & !backmat)
+ return(0);
+ /* mix returned ray values */
+ scalecolor(fr.rcol, coef);
+ scalecolor(br.rcol, 1.0-coef);
+ copycolor(r->rcol, fr.rcol);
+ addcolor(r->rcol, br.rcol);
+ r->rt = bright(fr.rcol) > bright(br.rcol) ? fr.rt : br.rt;
+ return(1);
}
double
+raydist(r, flags) /* compute (cumulative) ray distance */
+register RAY *r;
+register int flags;
+{
+ double sum = 0.0;
+
+ while (r != NULL && r->crtype&flags) {
+ sum += r->rot;
+ r = r->parent;
+ }
+ return(sum);
+}
+
+
+double
raynormal(norm, r) /* compute perturbed normal for ray */
FVECT norm;
register RAY *r;
@@ -210,7 +392,7 @@ register RAY *r;
* still fraught with problems since reflected rays and similar
* directions calculated from the surface normal may spawn rays behind
* the surface. The only solution is to curb textures at high
- * incidence (Rdot << 1).
+ * incidence (namely, keep DOT(rdir,pert) < Rdot).
*/
for (i = 0; i < 3; i++)
@@ -231,6 +413,44 @@ register RAY *r;
}
+void
+newrayxf(r) /* get new tranformation matrix for ray */
+RAY *r;
+{
+ static struct xfn {
+ struct xfn *next;
+ FULLXF xf;
+ } xfseed = { &xfseed }, *xflast = &xfseed;
+ register struct xfn *xp;
+ register RAY *rp;
+
+ /*
+ * Search for transform in circular list that
+ * has no associated ray in the tree.
+ */
+ xp = xflast;
+ for (rp = r->parent; rp != NULL; rp = rp->parent)
+ if (rp->rox == &xp->xf) { /* xp in use */
+ xp = xp->next; /* move to next */
+ if (xp == xflast) { /* need new one */
+ xp = (struct xfn *)malloc(sizeof(struct xfn));
+ if (xp == NULL)
+ error(SYSTEM,
+ "out of memory in newrayxf");
+ /* insert in list */
+ xp->next = xflast->next;
+ xflast->next = xp;
+ break; /* we're done */
+ }
+ rp = r; /* start check over */
+ }
+ /* got it */
+ r->rox = &xp->xf;
+ xflast = xp;
+}
+
+
+void
flipsurface(r) /* reverse surface orientation */
register RAY *r;
{
@@ -244,33 +464,44 @@ register RAY *r;
}
+int
localhit(r, scene) /* check for hit in the octree */
register RAY *r;
register CUBE *scene;
{
+ OBJECT cxset[MAXCSET+1]; /* set of checked objects */
FVECT curpos; /* current cube position */
- int mpos, mneg; /* sign flags */
+ int sflags; /* sign flags */
double t, dt;
register int i;
nrays++; /* increment trace counter */
-
- mpos = mneg = 0;
+ sflags = 0;
for (i = 0; i < 3; i++) {
curpos[i] = r->rorg[i];
- if (r->rdir[i] > FTINY)
- mpos |= 1 << i;
- else if (r->rdir[i] < -FTINY)
- mneg |= 1 << i;
+ if (r->rdir[i] > 1e-7)
+ sflags |= 1 << i;
+ else if (r->rdir[i] < -1e-7)
+ sflags |= 0x10 << i;
}
+ if (sflags == 0)
+ error(CONSISTENCY, "zero ray direction in localhit");
+ /* start off assuming nothing hit */
+ if (r->rmax > FTINY) { /* except aft plane if one */
+ r->ro = &Aftplane;
+ r->rot = r->rmax;
+ for (i = 0; i < 3; i++)
+ r->rop[i] = r->rorg[i] + r->rot*r->rdir[i];
+ }
+ /* find global cube entrance point */
t = 0.0;
if (!incube(scene, curpos)) {
/* find distance to entry */
for (i = 0; i < 3; i++) {
/* plane in our direction */
- if (mpos & 1<cuorg[i];
- else if (mneg & 1<cuorg[i] + scene->cusize;
else
continue;
@@ -280,6 +511,8 @@ register CUBE *scene;
t = dt; /* farthest face is the one */
}
t += FTINY; /* fudge to get inside cube */
+ if (t >= r->rot) /* clipped already */
+ return(0);
/* advance position */
for (i = 0; i < 3; i++)
curpos[i] += r->rdir[i]*t;
@@ -287,24 +520,26 @@ register CUBE *scene;
if (!incube(scene, curpos)) /* non-intersecting ray */
return(0);
}
- return(raymove(curpos, mpos, mneg, r, scene) == RAYHIT);
+ cxset[0] = 0;
+ raymove(curpos, cxset, sflags, r, scene);
+ return(r->ro != NULL & r->ro != &Aftplane);
}
static int
-raymove(pos, plus, minus, r, cu) /* check for hit as we move */
-FVECT pos; /* modified */
-int plus, minus; /* direction indicators to speed tests */
+raymove(pos, cxs, dirf, r, cu) /* check for hit as we move */
+FVECT pos; /* current position, modified herein */
+OBJECT *cxs; /* checked objects, modified by checkhit */
+int dirf; /* direction indicators to speed tests */
register RAY *r;
register CUBE *cu;
{
int ax;
double dt, t;
- register int sgn;
if (istree(cu->cutree)) { /* recurse on subcubes */
CUBE cukid;
- register int br;
+ register int br, sgn;
cukid.cusize = cu->cusize * 0.5; /* find subcube */
VCOPY(cukid.cuorg, cu->cuorg);
@@ -323,45 +558,47 @@ register CUBE *cu;
}
for ( ; ; ) {
cukid.cutree = octkid(cu->cutree, br);
- if ((ax = raymove(pos,plus,minus,r,&cukid)) == RAYHIT)
+ if ((ax = raymove(pos,cxs,dirf,r,&cukid)) == RAYHIT)
return(RAYHIT);
sgn = 1 << ax;
- if (sgn & minus) /* negative axis? */
- if (sgn & br) {
- cukid.cuorg[ax] -= cukid.cusize;
- br &= ~sgn;
- } else
- return(ax); /* underflow */
- else
+ if (sgn & dirf) /* positive axis? */
if (sgn & br)
return(ax); /* overflow */
else {
cukid.cuorg[ax] += cukid.cusize;
br |= sgn;
}
+ else
+ if (sgn & br) {
+ cukid.cuorg[ax] -= cukid.cusize;
+ br &= ~sgn;
+ } else
+ return(ax); /* underflow */
}
/*NOTREACHED*/
}
- if (isfull(cu->cutree) && checkhit(r, cu))
+ if (isfull(cu->cutree)) {
+ if (checkhit(r, cu, cxs))
+ return(RAYHIT);
+ } else if (r->ro == &Aftplane && incube(cu, r->rop))
return(RAYHIT);
/* advance to next cube */
- sgn = plus | minus;
- if (sgn&1) {
- dt = plus&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0];
+ if (dirf&0x11) {
+ dt = dirf&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0];
t = (dt - pos[0])/r->rdir[0];
ax = 0;
} else
t = FHUGE;
- if (sgn&2) {
- dt = plus&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1];
+ if (dirf&0x22) {
+ dt = dirf&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1];
dt = (dt - pos[1])/r->rdir[1];
if (dt < t) {
t = dt;
ax = 1;
}
}
- if (sgn&4) {
- dt = plus&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2];
+ if (dirf&0x44) {
+ dt = dirf&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2];
dt = (dt - pos[2])/r->rdir[2];
if (dt < t) {
t = dt;
@@ -375,25 +612,57 @@ register CUBE *cu;
}
-static
-checkhit(r, cu) /* check for hit in full cube */
+static int
+checkhit(r, cu, cxs) /* check for hit in full cube */
register RAY *r;
CUBE *cu;
+OBJECT *cxs;
{
OBJECT oset[MAXSET+1];
register OBJREC *o;
register int i;
objset(oset, cu->cutree);
+ checkset(oset, cxs); /* eliminate double-checking */
for (i = oset[0]; i > 0; i--) {
o = objptr(oset[i]);
- if (o->lastrno == r->rno) /* checked already? */
- continue;
- (*ofun[o->otype].funp)(o, r);
- o->lastrno = r->rno;
+ if ((*ofun[o->otype].funp)(o, r))
+ r->robj = oset[i];
}
if (r->ro == NULL)
return(0); /* no scores yet */
return(incube(cu, r->rop)); /* hit OK if in current cube */
+}
+
+
+static void
+checkset(os, cs) /* modify checked set and set to check */
+register OBJECT *os; /* os' = os - cs */
+register OBJECT *cs; /* cs' = cs + os */
+{
+ OBJECT cset[MAXCSET+MAXSET+1];
+ register int i, j;
+ int k;
+ /* copy os in place, cset <- cs */
+ cset[0] = 0;
+ k = 0;
+ for (i = j = 1; i <= os[0]; i++) {
+ while (j <= cs[0] && cs[j] < os[i])
+ cset[++cset[0]] = cs[j++];
+ if (j > cs[0] || os[i] != cs[j]) { /* object to check */
+ os[++k] = os[i];
+ cset[++cset[0]] = os[i];
+ }
+ }
+ if (!(os[0] = k)) /* new "to check" set size */
+ return; /* special case */
+ while (j <= cs[0]) /* get the rest of cs */
+ cset[++cset[0]] = cs[j++];
+ if (cset[0] > MAXCSET) /* truncate "checked" set if nec. */
+ cset[0] = MAXCSET;
+ /* setcopy(cs, cset); */ /* copy cset back to cs */
+ os = cset;
+ for (i = os[0]; i-- >= 0; )
+ *cs++ = *os++;
}