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/* Copyright (c) 1995 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 double 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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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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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->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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} |
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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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int gotmat; |
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|
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if (localhit(r, &thescene)) |
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gotmat = 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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gotmat = rayshade(r, r->ro->omod); /* distant source */ |
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|
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if (r->ro != NULL && !gotmat) |
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objerror(r->ro, USER, "material not found"); |
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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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r->ro->omod == OVOID) { |
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raytrans(r); |
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return(1); |
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} |
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return(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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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 dist; |
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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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if ((dist = r->rot) >= FHUGE) |
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dist = 2.*thescene.cusize; /* what to use for infinity? */ |
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if (r->crtype & SHADOW) |
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dist *= 1. - salbedo; /* no scattering for sources */ |
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if (dist <= FTINY) |
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return; /* no effective ray travel */ |
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re = dist*colval(r->cext,RED); |
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ge = dist*colval(r->cext,GRN); |
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be = dist*colval(r->cext,BLU); |
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setcolor(ce, re>92. ? 0. : exp(-re), |
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ge>92. ? 0. : exp(-ge), |
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be>92. ? 0. : exp(-be)); |
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multcolor(r->rcol, ce); /* path absorption */ |
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if (r->albedo <= FTINY || r->crtype & SHADOW) |
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return; /* no scattering */ |
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setcolor(ca, salbedo*colval(ambval,RED)*(1.-colval(ce,RED)), |
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salbedo*colval(ambval,GRN)*(1.-colval(ce,GRN)), |
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salbedo*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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/* 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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/* compute foreground and background */ |
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foremat = backmat = -1; |
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/* foreground */ |
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copystruct(&fr, r); |
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if (fore != OVOID && 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 (back != OVOID && coef < 1.0-FTINY) |
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backmat = rayshade(&br, back); |
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/* check */ |
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if (foremat < 0) |
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if (backmat < 0) |
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foremat = backmat = 0; |
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else |
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foremat = backmat; |
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else if (backmat < 0) |
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backmat = foremat; |
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if ((foremat==0) != (backmat==0)) |
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objerror(r->ro, USER, "mixing material with non-material"); |
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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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/* mix returned ray values */ |
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if (foremat) { |
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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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} |
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/* return value tells if material */ |
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return(foremat); |
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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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|
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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; |
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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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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; |
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FULLXF xf; |
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} xfseed = { &xfseed }, *xflast = &xfseed; |
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register struct xfn *xp; |
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register RAY *rp; |
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|
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/* |
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* Search for transform in circular list that |
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* has no associated ray in the tree. |
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*/ |
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xp = xflast; |
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for (rp = r->parent; rp != NULL; rp = rp->parent) |
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if (rp->rox == &xp->xf) { /* xp in use */ |
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xp = xp->next; /* move to next */ |
377 |
if (xp == xflast) { /* need new one */ |
378 |
xp = (struct xfn *)bmalloc(sizeof(struct xfn)); |
379 |
if (xp == NULL) |
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error(SYSTEM, |
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"out of memory in newrayxf"); |
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/* insert in list */ |
383 |
xp->next = xflast->next; |
384 |
xflast->next = xp; |
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break; /* we're done */ |
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} |
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rp = r; /* start check over */ |
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} |
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/* got it */ |
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r->rox = &xp->xf; |
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xflast = xp; |
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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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OBJECT cxset[MAXCSET+1]; /* set of checked objects */ |
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FVECT curpos; /* current cube position */ |
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int sflags; /* sign flags */ |
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double t, dt; |
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register int i; |
417 |
|
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nrays++; /* increment trace counter */ |
419 |
sflags = 0; |
420 |
for (i = 0; i < 3; i++) { |
421 |
curpos[i] = r->rorg[i]; |
422 |
if (r->rdir[i] > 1e-7) |
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sflags |= 1 << i; |
424 |
else if (r->rdir[i] < -1e-7) |
425 |
sflags |= 0x10 << i; |
426 |
} |
427 |
if (sflags == 0) |
428 |
error(CONSISTENCY, "zero ray direction in localhit"); |
429 |
/* start off assuming nothing hit */ |
430 |
if (r->rmax > FTINY) { /* except aft plane if one */ |
431 |
r->ro = &Aftplane; |
432 |
r->rot = r->rmax; |
433 |
for (i = 0; i < 3; i++) |
434 |
r->rop[i] = r->rorg[i] + r->rot*r->rdir[i]; |
435 |
} |
436 |
/* find global cube entrance point */ |
437 |
t = 0.0; |
438 |
if (!incube(scene, curpos)) { |
439 |
/* find distance to entry */ |
440 |
for (i = 0; i < 3; i++) { |
441 |
/* plane in our direction */ |
442 |
if (sflags & 1<<i) |
443 |
dt = scene->cuorg[i]; |
444 |
else if (sflags & 0x10<<i) |
445 |
dt = scene->cuorg[i] + scene->cusize; |
446 |
else |
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continue; |
448 |
/* distance to the plane */ |
449 |
dt = (dt - r->rorg[i])/r->rdir[i]; |
450 |
if (dt > t) |
451 |
t = dt; /* farthest face is the one */ |
452 |
} |
453 |
t += FTINY; /* fudge to get inside cube */ |
454 |
if (t >= r->rot) /* clipped already */ |
455 |
return(0); |
456 |
/* advance position */ |
457 |
for (i = 0; i < 3; i++) |
458 |
curpos[i] += r->rdir[i]*t; |
459 |
|
460 |
if (!incube(scene, curpos)) /* non-intersecting ray */ |
461 |
return(0); |
462 |
} |
463 |
cxset[0] = 0; |
464 |
raymove(curpos, cxset, sflags, r, scene); |
465 |
return(r->ro != NULL & r->ro != &Aftplane); |
466 |
} |
467 |
|
468 |
|
469 |
static int |
470 |
raymove(pos, cxs, dirf, r, cu) /* check for hit as we move */ |
471 |
FVECT pos; /* current position, modified herein */ |
472 |
OBJECT *cxs; /* checked objects, modified by checkhit */ |
473 |
int dirf; /* direction indicators to speed tests */ |
474 |
register RAY *r; |
475 |
register CUBE *cu; |
476 |
{ |
477 |
int ax; |
478 |
double dt, t; |
479 |
|
480 |
if (istree(cu->cutree)) { /* recurse on subcubes */ |
481 |
CUBE cukid; |
482 |
register int br, sgn; |
483 |
|
484 |
cukid.cusize = cu->cusize * 0.5; /* find subcube */ |
485 |
VCOPY(cukid.cuorg, cu->cuorg); |
486 |
br = 0; |
487 |
if (pos[0] >= cukid.cuorg[0]+cukid.cusize) { |
488 |
cukid.cuorg[0] += cukid.cusize; |
489 |
br |= 1; |
490 |
} |
491 |
if (pos[1] >= cukid.cuorg[1]+cukid.cusize) { |
492 |
cukid.cuorg[1] += cukid.cusize; |
493 |
br |= 2; |
494 |
} |
495 |
if (pos[2] >= cukid.cuorg[2]+cukid.cusize) { |
496 |
cukid.cuorg[2] += cukid.cusize; |
497 |
br |= 4; |
498 |
} |
499 |
for ( ; ; ) { |
500 |
cukid.cutree = octkid(cu->cutree, br); |
501 |
if ((ax = raymove(pos,cxs,dirf,r,&cukid)) == RAYHIT) |
502 |
return(RAYHIT); |
503 |
sgn = 1 << ax; |
504 |
if (sgn & dirf) /* positive axis? */ |
505 |
if (sgn & br) |
506 |
return(ax); /* overflow */ |
507 |
else { |
508 |
cukid.cuorg[ax] += cukid.cusize; |
509 |
br |= sgn; |
510 |
} |
511 |
else |
512 |
if (sgn & br) { |
513 |
cukid.cuorg[ax] -= cukid.cusize; |
514 |
br &= ~sgn; |
515 |
} else |
516 |
return(ax); /* underflow */ |
517 |
} |
518 |
/*NOTREACHED*/ |
519 |
} |
520 |
if (isfull(cu->cutree)) { |
521 |
if (checkhit(r, cu, cxs)) |
522 |
return(RAYHIT); |
523 |
} else if (r->ro == &Aftplane && incube(cu, r->rop)) |
524 |
return(RAYHIT); |
525 |
/* advance to next cube */ |
526 |
if (dirf&0x11) { |
527 |
dt = dirf&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0]; |
528 |
t = (dt - pos[0])/r->rdir[0]; |
529 |
ax = 0; |
530 |
} else |
531 |
t = FHUGE; |
532 |
if (dirf&0x22) { |
533 |
dt = dirf&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1]; |
534 |
dt = (dt - pos[1])/r->rdir[1]; |
535 |
if (dt < t) { |
536 |
t = dt; |
537 |
ax = 1; |
538 |
} |
539 |
} |
540 |
if (dirf&0x44) { |
541 |
dt = dirf&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2]; |
542 |
dt = (dt - pos[2])/r->rdir[2]; |
543 |
if (dt < t) { |
544 |
t = dt; |
545 |
ax = 2; |
546 |
} |
547 |
} |
548 |
pos[0] += r->rdir[0]*t; |
549 |
pos[1] += r->rdir[1]*t; |
550 |
pos[2] += r->rdir[2]*t; |
551 |
return(ax); |
552 |
} |
553 |
|
554 |
|
555 |
static |
556 |
checkhit(r, cu, cxs) /* check for hit in full cube */ |
557 |
register RAY *r; |
558 |
CUBE *cu; |
559 |
OBJECT *cxs; |
560 |
{ |
561 |
OBJECT oset[MAXSET+1]; |
562 |
register OBJREC *o; |
563 |
register int i; |
564 |
|
565 |
objset(oset, cu->cutree); |
566 |
checkset(oset, cxs); /* eliminate double-checking */ |
567 |
for (i = oset[0]; i > 0; i--) { |
568 |
o = objptr(oset[i]); |
569 |
(*ofun[o->otype].funp)(o, r); |
570 |
} |
571 |
if (r->ro == NULL) |
572 |
return(0); /* no scores yet */ |
573 |
|
574 |
return(incube(cu, r->rop)); /* hit OK if in current cube */ |
575 |
} |
576 |
|
577 |
|
578 |
static |
579 |
checkset(os, cs) /* modify checked set and set to check */ |
580 |
register OBJECT *os; /* os' = os - cs */ |
581 |
register OBJECT *cs; /* cs' = cs + os */ |
582 |
{ |
583 |
OBJECT cset[MAXCSET+MAXSET+1]; |
584 |
register int i, j; |
585 |
int k; |
586 |
/* copy os in place, cset <- cs */ |
587 |
cset[0] = 0; |
588 |
k = 0; |
589 |
for (i = j = 1; i <= os[0]; i++) { |
590 |
while (j <= cs[0] && cs[j] < os[i]) |
591 |
cset[++cset[0]] = cs[j++]; |
592 |
if (j > cs[0] || os[i] != cs[j]) { /* object to check */ |
593 |
os[++k] = os[i]; |
594 |
cset[++cset[0]] = os[i]; |
595 |
} |
596 |
} |
597 |
if (!(os[0] = k)) /* new "to check" set size */ |
598 |
return; /* special case */ |
599 |
while (j <= cs[0]) /* get the rest of cs */ |
600 |
cset[++cset[0]] = cs[j++]; |
601 |
if (cset[0] > MAXCSET) /* truncate "checked" set if nec. */ |
602 |
cset[0] = MAXCSET; |
603 |
/* setcopy(cs, cset); */ /* copy cset back to cs */ |
604 |
os = cset; |
605 |
for (i = os[0]; i-- >= 0; ) |
606 |
*cs++ = *os++; |
607 |
} |