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/* Copyright (c) 1986 Regents of the University of California */ |
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|
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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#endif |
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|
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/* |
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* raytrace.c - routines for tracing and shading rays. |
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* |
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* 8/7/85 |
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*/ |
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|
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#include "ray.h" |
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|
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#include "octree.h" |
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|
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#include "otypes.h" |
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|
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extern CUBE thescene; /* our scene */ |
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extern int maxdepth; /* maximum recursion depth */ |
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extern double minweight; /* minimum ray weight */ |
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|
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long nrays = 0L; /* number of rays traced */ |
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|
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#define MAXLOOP 128 /* modifier loop detection */ |
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|
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#define RAYHIT (-1) /* return value for intercepted ray */ |
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|
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|
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rayorigin(r, ro, rt, rw) /* start new ray from old one */ |
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register RAY *r, *ro; |
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int rt; |
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double rw; |
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{ |
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if ((r->parent = ro) == NULL) { /* primary ray */ |
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r->rlvl = 0; |
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r->rweight = rw; |
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r->crtype = r->rtype = rt; |
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r->rsrc = -1; |
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r->clipset = NULL; |
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} else { /* spawned ray */ |
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r->rlvl = ro->rlvl; |
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if (rt & RAYREFL) { |
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r->rlvl++; |
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r->rsrc = -1; |
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r->clipset = ro->clipset; |
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} else { |
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r->rsrc = ro->rsrc; |
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r->clipset = ro->newcset; |
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} |
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r->rweight = ro->rweight * rw; |
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r->crtype = ro->crtype | (r->rtype = rt); |
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VCOPY(r->rorg, ro->rop); |
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} |
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r->rno = nrays; |
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r->newcset = r->clipset; |
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r->ro = NULL; |
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r->rot = FHUGE; |
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r->pert[0] = r->pert[1] = r->pert[2] = 0.0; |
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setcolor(r->pcol, 1.0, 1.0, 1.0); |
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setcolor(r->rcol, 0.0, 0.0, 0.0); |
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r->rt = 0.0; |
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return(r->rlvl <= maxdepth && r->rweight >= minweight ? 0 : -1); |
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} |
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|
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|
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rayvalue(r) /* compute a ray's value */ |
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RAY *r; |
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{ |
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extern int (*trace)(); |
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|
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if (localhit(r, &thescene) || sourcehit(r)) |
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raycont(r); |
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|
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if (trace != NULL) |
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(*trace)(r); /* trace execution */ |
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} |
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|
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|
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raycont(r) /* check for clipped object and continue */ |
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register RAY *r; |
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{ |
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if (r->clipset != NULL && inset(r->clipset, r->ro->omod)) |
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raytrans(r); |
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else |
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rayshade(r, r->ro->omod); |
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} |
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|
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|
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raytrans(r) /* transmit ray as is */ |
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register RAY *r; |
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{ |
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RAY tr; |
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|
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if (rayorigin(&tr, r, TRANS, 1.0) == 0) { |
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VCOPY(tr.rdir, r->rdir); |
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rayvalue(&tr); |
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copycolor(r->rcol, tr.rcol); |
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r->rt = r->rot + tr.rt; |
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} |
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} |
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|
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|
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rayshade(r, mod) /* shade ray r with material mod */ |
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register RAY *r; |
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int mod; |
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{ |
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static int depth = 0; |
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register OBJREC *m; |
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/* check for infinite loop */ |
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if (depth++ >= MAXLOOP) |
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objerror(r->ro, USER, "possible modifier loop"); |
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for ( ; mod != OVOID; mod = m->omod) { |
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m = objptr(mod); |
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/****** unnecessary test since modifier() is always called |
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if (!ismodifier(m->otype)) { |
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sprintf(errmsg, "illegal modifier \"%s\"", m->oname); |
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error(USER, errmsg); |
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} |
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******/ |
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(*ofun[m->otype].funp)(m, r); /* execute function */ |
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m->lastrno = r->rno; |
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if (ismaterial(m->otype)) { /* materials call raytexture */ |
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depth--; |
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return; /* we're done */ |
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} |
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} |
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objerror(r->ro, USER, "material not found"); |
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} |
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|
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|
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raytexture(r, mod) /* get material modifiers */ |
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RAY *r; |
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int mod; |
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{ |
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static int depth = 0; |
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register OBJREC *m; |
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/* check for infinite loop */ |
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if (depth++ >= MAXLOOP) |
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objerror(r->ro, USER, "modifier loop"); |
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/* execute textures and patterns */ |
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for ( ; mod != OVOID; mod = m->omod) { |
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m = objptr(mod); |
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if (!istexture(m->otype)) { |
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sprintf(errmsg, "illegal modifier \"%s\"", m->oname); |
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error(USER, errmsg); |
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} |
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(*ofun[m->otype].funp)(m, r); |
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m->lastrno = r->rno; |
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} |
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depth--; /* end here */ |
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} |
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|
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|
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raymixture(r, fore, back, coef) /* mix modifiers */ |
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register RAY *r; |
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OBJECT fore, back; |
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double coef; |
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{ |
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FVECT curpert, forepert, backpert; |
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COLOR curpcol, forepcol, backpcol; |
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register int i; |
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/* clip coefficient */ |
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if (coef > 1.0) |
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coef = 1.0; |
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else if (coef < 0.0) |
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coef = 0.0; |
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/* save current mods */ |
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VCOPY(curpert, r->pert); |
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copycolor(curpcol, r->pcol); |
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/* compute new mods */ |
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/* foreground */ |
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r->pert[0] = r->pert[1] = r->pert[2] = 0.0; |
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setcolor(r->pcol, 1.0, 1.0, 1.0); |
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if (fore != OVOID && coef > FTINY) |
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raytexture(r, fore); |
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VCOPY(forepert, r->pert); |
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copycolor(forepcol, r->pcol); |
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/* background */ |
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r->pert[0] = r->pert[1] = r->pert[2] = 0.0; |
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setcolor(r->pcol, 1.0, 1.0, 1.0); |
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if (back != OVOID && coef < 1.0-FTINY) |
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raytexture(r, back); |
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VCOPY(backpert, r->pert); |
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copycolor(backpcol, r->pcol); |
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/* sum perturbations */ |
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for (i = 0; i < 3; i++) |
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r->pert[i] = curpert[i] + coef*forepert[i] + |
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(1.0-coef)*backpert[i]; |
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/* multiply colors */ |
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setcolor(r->pcol, coef*colval(forepcol,RED) + |
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(1.0-coef)*colval(backpcol,RED), |
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coef*colval(forepcol,GRN) + |
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(1.0-coef)*colval(backpcol,GRN), |
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coef*colval(forepcol,BLU) + |
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(1.0-coef)*colval(backpcol,BLU)); |
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multcolor(r->pcol, curpcol); |
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} |
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|
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|
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double |
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raynormal(norm, r) /* compute perturbed normal for ray */ |
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FVECT norm; |
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register RAY *r; |
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{ |
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double newdot; |
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register int i; |
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|
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/* The perturbation is added to the surface normal to obtain |
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* the new normal. If the new normal would affect the surface |
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* orientation wrt. the ray, a correction is made. The method is |
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* still fraught with problems since reflected rays and similar |
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* directions calculated from the surface normal may spawn rays behind |
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* the surface. The only solution is to curb textures at high |
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* incidence (namely, keep DOT(rdir,pert) < Rdot). |
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*/ |
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|
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for (i = 0; i < 3; i++) |
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norm[i] = r->ron[i] + r->pert[i]; |
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|
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if (normalize(norm) == 0.0) { |
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objerror(r->ro, WARNING, "illegal normal perturbation"); |
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VCOPY(norm, r->ron); |
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return(r->rod); |
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} |
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newdot = -DOT(norm, r->rdir); |
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if ((newdot > 0.0) != (r->rod > 0.0)) { /* fix orientation */ |
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for (i = 0; i < 3; i++) |
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norm[i] += 2.0*newdot*r->rdir[i]; |
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newdot = -newdot; |
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} |
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return(newdot); |
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} |
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|
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|
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flipsurface(r) /* reverse surface orientation */ |
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register RAY *r; |
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{ |
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r->rod = -r->rod; |
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r->ron[0] = -r->ron[0]; |
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r->ron[1] = -r->ron[1]; |
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r->ron[2] = -r->ron[2]; |
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r->pert[0] = -r->pert[0]; |
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r->pert[1] = -r->pert[1]; |
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r->pert[2] = -r->pert[2]; |
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} |
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|
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|
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localhit(r, scene) /* check for hit in the octree */ |
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register RAY *r; |
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register CUBE *scene; |
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{ |
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FVECT curpos; /* current cube position */ |
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int mpos, mneg; /* sign flags */ |
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double t, dt; |
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register int i; |
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|
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nrays++; /* increment trace counter */ |
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|
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mpos = mneg = 0; |
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for (i = 0; i < 3; i++) { |
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curpos[i] = r->rorg[i]; |
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if (r->rdir[i] > FTINY) |
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mpos |= 1 << i; |
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else if (r->rdir[i] < -FTINY) |
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mneg |= 1 << i; |
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} |
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t = 0.0; |
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if (!incube(scene, curpos)) { |
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/* find distance to entry */ |
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for (i = 0; i < 3; i++) { |
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/* plane in our direction */ |
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if (mpos & 1<<i) |
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dt = scene->cuorg[i]; |
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else if (mneg & 1<<i) |
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dt = scene->cuorg[i] + scene->cusize; |
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else |
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continue; |
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/* distance to the plane */ |
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dt = (dt - r->rorg[i])/r->rdir[i]; |
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if (dt > t) |
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t = dt; /* farthest face is the one */ |
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} |
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t += FTINY; /* fudge to get inside cube */ |
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/* advance position */ |
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for (i = 0; i < 3; i++) |
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curpos[i] += r->rdir[i]*t; |
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|
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if (!incube(scene, curpos)) /* non-intersecting ray */ |
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return(0); |
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} |
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return(raymove(curpos, mpos, mneg, r, scene) == RAYHIT); |
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} |
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|
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|
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static int |
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raymove(pos, plus, minus, r, cu) /* check for hit as we move */ |
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FVECT pos; /* modified */ |
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int plus, minus; /* direction indicators to speed tests */ |
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register RAY *r; |
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register CUBE *cu; |
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{ |
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int ax; |
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double dt, t; |
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register int sgn; |
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|
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if (istree(cu->cutree)) { /* recurse on subcubes */ |
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CUBE cukid; |
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register int br; |
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|
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cukid.cusize = cu->cusize * 0.5; /* find subcube */ |
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VCOPY(cukid.cuorg, cu->cuorg); |
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br = 0; |
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if (pos[0] >= cukid.cuorg[0]+cukid.cusize) { |
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cukid.cuorg[0] += cukid.cusize; |
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br |= 1; |
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} |
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if (pos[1] >= cukid.cuorg[1]+cukid.cusize) { |
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cukid.cuorg[1] += cukid.cusize; |
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br |= 2; |
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} |
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if (pos[2] >= cukid.cuorg[2]+cukid.cusize) { |
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cukid.cuorg[2] += cukid.cusize; |
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br |= 4; |
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} |
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for ( ; ; ) { |
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cukid.cutree = octkid(cu->cutree, br); |
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if ((ax = raymove(pos,plus,minus,r,&cukid)) == RAYHIT) |
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return(RAYHIT); |
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sgn = 1 << ax; |
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if (sgn & minus) /* negative axis? */ |
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if (sgn & br) { |
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cukid.cuorg[ax] -= cukid.cusize; |
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br &= ~sgn; |
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} else |
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return(ax); /* underflow */ |
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else |
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if (sgn & br) |
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return(ax); /* overflow */ |
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else { |
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cukid.cuorg[ax] += cukid.cusize; |
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br |= sgn; |
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} |
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} |
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/*NOTREACHED*/ |
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} |
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if (isfull(cu->cutree) && checkhit(r, cu)) |
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return(RAYHIT); |
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/* advance to next cube */ |
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sgn = plus | minus; |
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if (sgn&1) { |
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dt = plus&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0]; |
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t = (dt - pos[0])/r->rdir[0]; |
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ax = 0; |
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} else |
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t = FHUGE; |
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if (sgn&2) { |
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dt = plus&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1]; |
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dt = (dt - pos[1])/r->rdir[1]; |
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if (dt < t) { |
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t = dt; |
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ax = 1; |
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} |
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} |
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if (sgn&4) { |
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dt = plus&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2]; |
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dt = (dt - pos[2])/r->rdir[2]; |
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if (dt < t) { |
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t = dt; |
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ax = 2; |
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} |
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} |
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pos[0] += r->rdir[0]*t; |
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pos[1] += r->rdir[1]*t; |
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pos[2] += r->rdir[2]*t; |
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return(ax); |
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} |
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|
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|
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static |
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checkhit(r, cu) /* check for hit in full cube */ |
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register RAY *r; |
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CUBE *cu; |
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{ |
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OBJECT oset[MAXSET+1]; |
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register OBJREC *o; |
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register int i; |
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|
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objset(oset, cu->cutree); |
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for (i = oset[0]; i > 0; i--) { |
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o = objptr(oset[i]); |
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if (o->lastrno == r->rno) /* checked already? */ |
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continue; |
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(*ofun[o->otype].funp)(o, r); |
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o->lastrno = r->rno; |
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} |
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if (r->ro == NULL) |
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return(0); /* no scores yet */ |
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|
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return(incube(cu, r->rop)); /* hit OK if in current cube */ |
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} |
