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/* Copyright (c) 1996 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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#include "otspecial.h" |
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|
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#define MAXCSET ((MAXSET+1)*2-1) /* maximum check set size */ |
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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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extern int do_irrad; /* compute irradiance? */ |
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extern COLOR ambval; /* ambient value */ |
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|
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extern COLOR cextinction; /* global extinction coefficient */ |
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extern COLOR salbedo; /* global scattering albedo */ |
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extern double seccg; /* global scattering eccentricity */ |
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extern double ssampdist; /* scatter sampling distance */ |
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|
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unsigned long raynum = 0; /* next unique ray number */ |
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unsigned long nrays = 0; /* number of calls to localhit */ |
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|
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static FLOAT Lambfa[5] = {PI, PI, PI, 0.0, 0.0}; |
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OBJREC Lamb = { |
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OVOID, MAT_PLASTIC, "Lambertian", |
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{0, 5, NULL, Lambfa}, NULL, |
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}; /* a Lambertian surface */ |
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|
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OBJREC Aftplane; /* aft clipping plane object */ |
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|
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static int raymove(), checkset(), checkhit(); |
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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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r->revf = raytrace; |
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copycolor(r->cext, cextinction); |
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copycolor(r->albedo, salbedo); |
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r->gecc = seccg; |
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r->slights = 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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r->rmax = 0.0; |
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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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r->rmax = ro->rmax <= FTINY ? 0.0 : ro->rmax - ro->rot; |
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} |
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r->revf = ro->revf; |
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copycolor(r->cext, ro->cext); |
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copycolor(r->albedo, ro->albedo); |
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r->gecc = ro->gecc; |
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r->slights = ro->slights; |
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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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rayclear(r); |
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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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rayclear(r) /* clear a ray for (re)evaluation */ |
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register RAY *r; |
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{ |
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r->rno = raynum++; |
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r->newcset = r->clipset; |
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r->robj = OVOID; |
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r->ro = NULL; |
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r->rt = 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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} |
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|
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|
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raytrace(r) /* trace a ray and compute its 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)) |
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raycont(r); /* hit local surface, evaluate */ |
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else if (r->ro == &Aftplane) { |
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r->ro = NULL; /* hit aft clipping plane */ |
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r->rot = FHUGE; |
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} else if (sourcehit(r)) |
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rayshade(r, r->ro->omod); /* distant source */ |
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|
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rayparticipate(r); /* for participating medium */ |
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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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!rayshade(r, r->ro->omod)) |
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raytrans(r); |
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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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int gotmat; |
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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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r->rt = r->rot; /* set effective ray length */ |
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for (gotmat = 0; !gotmat && 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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/* hack for irradiance calculation */ |
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if (do_irrad && !(r->crtype & ~(PRIMARY|TRANS))) { |
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if (irr_ignore(m->otype)) { |
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depth--; |
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raytrans(r); |
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return(1); |
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} |
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if (!islight(m->otype)) |
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m = &Lamb; |
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} |
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/* materials call raytexture */ |
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gotmat = (*ofun[m->otype].funp)(m, r); |
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} |
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depth--; |
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return(gotmat); |
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} |
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|
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|
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rayparticipate(r) /* compute ray medium participation */ |
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register RAY *r; |
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{ |
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COLOR ce, ca; |
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double re, ge, be; |
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|
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if (intens(r->cext) <= 1./FHUGE) |
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return; /* no medium */ |
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re = r->rot*colval(r->cext,RED); |
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ge = r->rot*colval(r->cext,GRN); |
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be = r->rot*colval(r->cext,BLU); |
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if (r->crtype & SHADOW) { /* no scattering for sources */ |
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re *= 1. - colval(r->albedo,RED); |
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ge *= 1. - colval(r->albedo,GRN); |
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be *= 1. - colval(r->albedo,BLU); |
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} |
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setcolor(ce, re<=0. ? 1. : re>92. ? 0. : exp(-re), |
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ge<=0. ? 1. : ge>92. ? 0. : exp(-ge), |
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be<=0. ? 1. : be>92. ? 0. : exp(-be)); |
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multcolor(r->rcol, ce); /* path absorption */ |
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if (r->crtype & SHADOW || intens(r->albedo) <= FTINY) |
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return; /* no scattering */ |
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setcolor(ca, |
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colval(r->albedo,RED)*colval(ambval,RED)*(1.-colval(ce,RED)), |
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colval(r->albedo,GRN)*colval(ambval,GRN)*(1.-colval(ce,GRN)), |
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colval(r->albedo,BLU)*colval(ambval,BLU)*(1.-colval(ce,BLU))); |
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addcolor(r->rcol, ca); /* ambient in scattering */ |
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srcscatter(r); /* source in scattering */ |
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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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/****** 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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if ((*ofun[m->otype].funp)(m, r)) { |
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sprintf(errmsg, "conflicting material \"%s\"", |
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m->oname); |
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objerror(r->ro, USER, errmsg); |
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} |
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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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RAY fr, br; |
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int foremat, backmat; |
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register int i; |
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/* bound 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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/* compute foreground and background */ |
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foremat = backmat = 0; |
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/* foreground */ |
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copystruct(&fr, r); |
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if (coef > FTINY) |
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foremat = rayshade(&fr, fore); |
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/* background */ |
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copystruct(&br, r); |
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if (coef < 1.0-FTINY) |
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backmat = rayshade(&br, back); |
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/* check for transparency */ |
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if (backmat ^ foremat) |
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if (backmat && coef > FTINY) |
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raytrans(&fr); |
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else if (foremat && coef < 1.0-FTINY) |
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raytrans(&br); |
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/* mix perturbations */ |
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for (i = 0; i < 3; i++) |
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r->pert[i] = coef*fr.pert[i] + (1.0-coef)*br.pert[i]; |
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/* mix pattern colors */ |
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scalecolor(fr.pcol, coef); |
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scalecolor(br.pcol, 1.0-coef); |
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copycolor(r->pcol, fr.pcol); |
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addcolor(r->pcol, br.pcol); |
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/* return value tells if material */ |
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if (!foremat & !backmat) |
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return(0); |
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/* mix returned ray values */ |
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scalecolor(fr.rcol, coef); |
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scalecolor(br.rcol, 1.0-coef); |
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copycolor(r->rcol, fr.rcol); |
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addcolor(r->rcol, br.rcol); |
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r->rt = bright(fr.rcol) > bright(br.rcol) ? fr.rt : br.rt; |
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return(1); |
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} |
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|
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|
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double |
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raydist(r, flags) /* compute (cumulative) ray distance */ |
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register RAY *r; |
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register int flags; |
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{ |
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double sum = 0.0; |
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|
304 |
while (r != NULL && r->crtype&flags) { |
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sum += r->rot; |
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r = r->parent; |
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} |
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return(sum); |
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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; |
319 |
|
320 |
/* 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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*/ |
328 |
|
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for (i = 0; i < 3; i++) |
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norm[i] = r->ron[i] + r->pert[i]; |
331 |
|
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if (normalize(norm) == 0.0) { |
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objerror(r->ro, WARNING, "illegal normal perturbation"); |
334 |
VCOPY(norm, r->ron); |
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return(r->rod); |
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} |
337 |
newdot = -DOT(norm, r->rdir); |
338 |
if ((newdot > 0.0) != (r->rod > 0.0)) { /* fix orientation */ |
339 |
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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newrayxf(r) /* get new tranformation matrix for ray */ |
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RAY *r; |
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{ |
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static struct xfn { |
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struct xfn *next; |
352 |
FULLXF xf; |
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} xfseed = { &xfseed }, *xflast = &xfseed; |
354 |
register struct xfn *xp; |
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register RAY *rp; |
356 |
|
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/* |
358 |
* Search for transform in circular list that |
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* has no associated ray in the tree. |
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*/ |
361 |
xp = xflast; |
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for (rp = r->parent; rp != NULL; rp = rp->parent) |
363 |
if (rp->rox == &xp->xf) { /* xp in use */ |
364 |
xp = xp->next; /* move to next */ |
365 |
if (xp == xflast) { /* need new one */ |
366 |
xp = (struct xfn *)bmalloc(sizeof(struct xfn)); |
367 |
if (xp == NULL) |
368 |
error(SYSTEM, |
369 |
"out of memory in newrayxf"); |
370 |
/* insert in list */ |
371 |
xp->next = xflast->next; |
372 |
xflast->next = xp; |
373 |
break; /* we're done */ |
374 |
} |
375 |
rp = r; /* start check over */ |
376 |
} |
377 |
/* got it */ |
378 |
r->rox = &xp->xf; |
379 |
xflast = xp; |
380 |
} |
381 |
|
382 |
|
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flipsurface(r) /* reverse surface orientation */ |
384 |
register RAY *r; |
385 |
{ |
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r->rod = -r->rod; |
387 |
r->ron[0] = -r->ron[0]; |
388 |
r->ron[1] = -r->ron[1]; |
389 |
r->ron[2] = -r->ron[2]; |
390 |
r->pert[0] = -r->pert[0]; |
391 |
r->pert[1] = -r->pert[1]; |
392 |
r->pert[2] = -r->pert[2]; |
393 |
} |
394 |
|
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|
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localhit(r, scene) /* check for hit in the octree */ |
397 |
register RAY *r; |
398 |
register CUBE *scene; |
399 |
{ |
400 |
OBJECT cxset[MAXCSET+1]; /* set of checked objects */ |
401 |
FVECT curpos; /* current cube position */ |
402 |
int sflags; /* sign flags */ |
403 |
double t, dt; |
404 |
register int i; |
405 |
|
406 |
nrays++; /* increment trace counter */ |
407 |
sflags = 0; |
408 |
for (i = 0; i < 3; i++) { |
409 |
curpos[i] = r->rorg[i]; |
410 |
if (r->rdir[i] > 1e-7) |
411 |
sflags |= 1 << i; |
412 |
else if (r->rdir[i] < -1e-7) |
413 |
sflags |= 0x10 << i; |
414 |
} |
415 |
if (sflags == 0) |
416 |
error(CONSISTENCY, "zero ray direction in localhit"); |
417 |
/* start off assuming nothing hit */ |
418 |
if (r->rmax > FTINY) { /* except aft plane if one */ |
419 |
r->ro = &Aftplane; |
420 |
r->rot = r->rmax; |
421 |
for (i = 0; i < 3; i++) |
422 |
r->rop[i] = r->rorg[i] + r->rot*r->rdir[i]; |
423 |
} |
424 |
/* find global cube entrance point */ |
425 |
t = 0.0; |
426 |
if (!incube(scene, curpos)) { |
427 |
/* find distance to entry */ |
428 |
for (i = 0; i < 3; i++) { |
429 |
/* plane in our direction */ |
430 |
if (sflags & 1<<i) |
431 |
dt = scene->cuorg[i]; |
432 |
else if (sflags & 0x10<<i) |
433 |
dt = scene->cuorg[i] + scene->cusize; |
434 |
else |
435 |
continue; |
436 |
/* distance to the plane */ |
437 |
dt = (dt - r->rorg[i])/r->rdir[i]; |
438 |
if (dt > t) |
439 |
t = dt; /* farthest face is the one */ |
440 |
} |
441 |
t += FTINY; /* fudge to get inside cube */ |
442 |
if (t >= r->rot) /* clipped already */ |
443 |
return(0); |
444 |
/* advance position */ |
445 |
for (i = 0; i < 3; i++) |
446 |
curpos[i] += r->rdir[i]*t; |
447 |
|
448 |
if (!incube(scene, curpos)) /* non-intersecting ray */ |
449 |
return(0); |
450 |
} |
451 |
cxset[0] = 0; |
452 |
raymove(curpos, cxset, sflags, r, scene); |
453 |
return(r->ro != NULL & r->ro != &Aftplane); |
454 |
} |
455 |
|
456 |
|
457 |
static int |
458 |
raymove(pos, cxs, dirf, r, cu) /* check for hit as we move */ |
459 |
FVECT pos; /* current position, modified herein */ |
460 |
OBJECT *cxs; /* checked objects, modified by checkhit */ |
461 |
int dirf; /* direction indicators to speed tests */ |
462 |
register RAY *r; |
463 |
register CUBE *cu; |
464 |
{ |
465 |
int ax; |
466 |
double dt, t; |
467 |
|
468 |
if (istree(cu->cutree)) { /* recurse on subcubes */ |
469 |
CUBE cukid; |
470 |
register int br, sgn; |
471 |
|
472 |
cukid.cusize = cu->cusize * 0.5; /* find subcube */ |
473 |
VCOPY(cukid.cuorg, cu->cuorg); |
474 |
br = 0; |
475 |
if (pos[0] >= cukid.cuorg[0]+cukid.cusize) { |
476 |
cukid.cuorg[0] += cukid.cusize; |
477 |
br |= 1; |
478 |
} |
479 |
if (pos[1] >= cukid.cuorg[1]+cukid.cusize) { |
480 |
cukid.cuorg[1] += cukid.cusize; |
481 |
br |= 2; |
482 |
} |
483 |
if (pos[2] >= cukid.cuorg[2]+cukid.cusize) { |
484 |
cukid.cuorg[2] += cukid.cusize; |
485 |
br |= 4; |
486 |
} |
487 |
for ( ; ; ) { |
488 |
cukid.cutree = octkid(cu->cutree, br); |
489 |
if ((ax = raymove(pos,cxs,dirf,r,&cukid)) == RAYHIT) |
490 |
return(RAYHIT); |
491 |
sgn = 1 << ax; |
492 |
if (sgn & dirf) /* positive axis? */ |
493 |
if (sgn & br) |
494 |
return(ax); /* overflow */ |
495 |
else { |
496 |
cukid.cuorg[ax] += cukid.cusize; |
497 |
br |= sgn; |
498 |
} |
499 |
else |
500 |
if (sgn & br) { |
501 |
cukid.cuorg[ax] -= cukid.cusize; |
502 |
br &= ~sgn; |
503 |
} else |
504 |
return(ax); /* underflow */ |
505 |
} |
506 |
/*NOTREACHED*/ |
507 |
} |
508 |
if (isfull(cu->cutree)) { |
509 |
if (checkhit(r, cu, cxs)) |
510 |
return(RAYHIT); |
511 |
} else if (r->ro == &Aftplane && incube(cu, r->rop)) |
512 |
return(RAYHIT); |
513 |
/* advance to next cube */ |
514 |
if (dirf&0x11) { |
515 |
dt = dirf&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0]; |
516 |
t = (dt - pos[0])/r->rdir[0]; |
517 |
ax = 0; |
518 |
} else |
519 |
t = FHUGE; |
520 |
if (dirf&0x22) { |
521 |
dt = dirf&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1]; |
522 |
dt = (dt - pos[1])/r->rdir[1]; |
523 |
if (dt < t) { |
524 |
t = dt; |
525 |
ax = 1; |
526 |
} |
527 |
} |
528 |
if (dirf&0x44) { |
529 |
dt = dirf&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2]; |
530 |
dt = (dt - pos[2])/r->rdir[2]; |
531 |
if (dt < t) { |
532 |
t = dt; |
533 |
ax = 2; |
534 |
} |
535 |
} |
536 |
pos[0] += r->rdir[0]*t; |
537 |
pos[1] += r->rdir[1]*t; |
538 |
pos[2] += r->rdir[2]*t; |
539 |
return(ax); |
540 |
} |
541 |
|
542 |
|
543 |
static |
544 |
checkhit(r, cu, cxs) /* check for hit in full cube */ |
545 |
register RAY *r; |
546 |
CUBE *cu; |
547 |
OBJECT *cxs; |
548 |
{ |
549 |
OBJECT oset[MAXSET+1]; |
550 |
register OBJREC *o; |
551 |
register int i; |
552 |
|
553 |
objset(oset, cu->cutree); |
554 |
checkset(oset, cxs); /* eliminate double-checking */ |
555 |
for (i = oset[0]; i > 0; i--) { |
556 |
o = objptr(oset[i]); |
557 |
if ((*ofun[o->otype].funp)(o, r)) |
558 |
r->robj = oset[i]; |
559 |
} |
560 |
if (r->ro == NULL) |
561 |
return(0); /* no scores yet */ |
562 |
|
563 |
return(incube(cu, r->rop)); /* hit OK if in current cube */ |
564 |
} |
565 |
|
566 |
|
567 |
static |
568 |
checkset(os, cs) /* modify checked set and set to check */ |
569 |
register OBJECT *os; /* os' = os - cs */ |
570 |
register OBJECT *cs; /* cs' = cs + os */ |
571 |
{ |
572 |
OBJECT cset[MAXCSET+MAXSET+1]; |
573 |
register int i, j; |
574 |
int k; |
575 |
/* copy os in place, cset <- cs */ |
576 |
cset[0] = 0; |
577 |
k = 0; |
578 |
for (i = j = 1; i <= os[0]; i++) { |
579 |
while (j <= cs[0] && cs[j] < os[i]) |
580 |
cset[++cset[0]] = cs[j++]; |
581 |
if (j > cs[0] || os[i] != cs[j]) { /* object to check */ |
582 |
os[++k] = os[i]; |
583 |
cset[++cset[0]] = os[i]; |
584 |
} |
585 |
} |
586 |
if (!(os[0] = k)) /* new "to check" set size */ |
587 |
return; /* special case */ |
588 |
while (j <= cs[0]) /* get the rest of cs */ |
589 |
cset[++cset[0]] = cs[j++]; |
590 |
if (cset[0] > MAXCSET) /* truncate "checked" set if nec. */ |
591 |
cset[0] = MAXCSET; |
592 |
/* setcopy(cs, cset); */ /* copy cset back to cs */ |
593 |
os = cset; |
594 |
for (i = os[0]; i-- >= 0; ) |
595 |
*cs++ = *os++; |
596 |
} |