| 1 |
/* Copyright (c) 1998 Silicon Graphics, Inc. */ |
| 2 |
|
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#ifndef lint |
| 4 |
static char SCCSid[] = "$SunId$ SGI"; |
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#endif |
| 6 |
|
| 7 |
/* |
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* raytrace.c - routines for tracing and shading rays. |
| 9 |
* |
| 10 |
* 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" |
| 16 |
|
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#include "otypes.h" |
| 18 |
|
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#include "otspecial.h" |
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|
| 21 |
#define MAXCSET ((MAXSET+1)*2-1) /* maximum check set size */ |
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|
| 23 |
extern CUBE thescene; /* our scene */ |
| 24 |
extern int maxdepth; /* maximum recursion depth */ |
| 25 |
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 */ |
| 30 |
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, |
| 41 |
}; /* 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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#ifndef MAXLOOP |
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#define MAXLOOP 0 /* modifier loop detection */ |
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#endif |
| 50 |
|
| 51 |
#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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double re; |
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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->crtype = ro->crtype | (r->rtype = rt); |
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VCOPY(r->rorg, ro->rop); |
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r->rweight = ro->rweight * rw; |
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/* estimate absorption */ |
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re = colval(ro->cext,RED) < colval(ro->cext,GRN) ? |
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colval(ro->cext,RED) : colval(ro->cext,GRN); |
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if (colval(ro->cext,BLU) < re) re = colval(ro->cext,BLU); |
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if (re > 0.) |
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r->rweight *= exp(-re*ro->rot); |
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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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int gotmat; |
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register OBJREC *m; |
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#if MAXLOOP |
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static int depth = 0; |
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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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#endif |
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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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#if MAXLOOP |
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depth--; |
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#endif |
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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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#if MAXLOOP |
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depth--; |
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#endif |
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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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register OBJREC *m; |
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#if MAXLOOP |
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static int depth = 0; |
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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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#endif |
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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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#if MAXLOOP |
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depth--; /* end here */ |
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#endif |
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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 */ |
| 297 |
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 */ |
| 319 |
register RAY *r; |
| 320 |
register int flags; |
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{ |
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double sum = 0.0; |
| 323 |
|
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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 */ |
| 334 |
FVECT norm; |
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register RAY *r; |
| 336 |
{ |
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double newdot; |
| 338 |
register int i; |
| 339 |
|
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/* The perturbation is added to the surface normal to obtain |
| 341 |
* the new normal. If the new normal would affect the surface |
| 342 |
* orientation wrt. the ray, a correction is made. The method is |
| 343 |
* still fraught with problems since reflected rays and similar |
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* directions calculated from the surface normal may spawn rays behind |
| 345 |
* the surface. The only solution is to curb textures at high |
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* incidence (namely, keep DOT(rdir,pert) < Rdot). |
| 347 |
*/ |
| 348 |
|
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for (i = 0; i < 3; i++) |
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norm[i] = r->ron[i] + r->pert[i]; |
| 351 |
|
| 352 |
if (normalize(norm) == 0.0) { |
| 353 |
objerror(r->ro, WARNING, "illegal normal perturbation"); |
| 354 |
VCOPY(norm, r->ron); |
| 355 |
return(r->rod); |
| 356 |
} |
| 357 |
newdot = -DOT(norm, r->rdir); |
| 358 |
if ((newdot > 0.0) != (r->rod > 0.0)) { /* fix orientation */ |
| 359 |
for (i = 0; i < 3; i++) |
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norm[i] += 2.0*newdot*r->rdir[i]; |
| 361 |
newdot = -newdot; |
| 362 |
} |
| 363 |
return(newdot); |
| 364 |
} |
| 365 |
|
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|
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newrayxf(r) /* get new tranformation matrix for ray */ |
| 368 |
RAY *r; |
| 369 |
{ |
| 370 |
static struct xfn { |
| 371 |
struct xfn *next; |
| 372 |
FULLXF xf; |
| 373 |
} xfseed = { &xfseed }, *xflast = &xfseed; |
| 374 |
register struct xfn *xp; |
| 375 |
register RAY *rp; |
| 376 |
|
| 377 |
/* |
| 378 |
* Search for transform in circular list that |
| 379 |
* has no associated ray in the tree. |
| 380 |
*/ |
| 381 |
xp = xflast; |
| 382 |
for (rp = r->parent; rp != NULL; rp = rp->parent) |
| 383 |
if (rp->rox == &xp->xf) { /* xp in use */ |
| 384 |
xp = xp->next; /* move to next */ |
| 385 |
if (xp == xflast) { /* need new one */ |
| 386 |
xp = (struct xfn *)bmalloc(sizeof(struct xfn)); |
| 387 |
if (xp == NULL) |
| 388 |
error(SYSTEM, |
| 389 |
"out of memory in newrayxf"); |
| 390 |
/* insert in list */ |
| 391 |
xp->next = xflast->next; |
| 392 |
xflast->next = xp; |
| 393 |
break; /* we're done */ |
| 394 |
} |
| 395 |
rp = r; /* start check over */ |
| 396 |
} |
| 397 |
/* got it */ |
| 398 |
r->rox = &xp->xf; |
| 399 |
xflast = xp; |
| 400 |
} |
| 401 |
|
| 402 |
|
| 403 |
flipsurface(r) /* reverse surface orientation */ |
| 404 |
register RAY *r; |
| 405 |
{ |
| 406 |
r->rod = -r->rod; |
| 407 |
r->ron[0] = -r->ron[0]; |
| 408 |
r->ron[1] = -r->ron[1]; |
| 409 |
r->ron[2] = -r->ron[2]; |
| 410 |
r->pert[0] = -r->pert[0]; |
| 411 |
r->pert[1] = -r->pert[1]; |
| 412 |
r->pert[2] = -r->pert[2]; |
| 413 |
} |
| 414 |
|
| 415 |
|
| 416 |
localhit(r, scene) /* check for hit in the octree */ |
| 417 |
register RAY *r; |
| 418 |
register CUBE *scene; |
| 419 |
{ |
| 420 |
OBJECT cxset[MAXCSET+1]; /* set of checked objects */ |
| 421 |
FVECT curpos; /* current cube position */ |
| 422 |
int sflags; /* sign flags */ |
| 423 |
double t, dt; |
| 424 |
register int i; |
| 425 |
|
| 426 |
nrays++; /* increment trace counter */ |
| 427 |
sflags = 0; |
| 428 |
for (i = 0; i < 3; i++) { |
| 429 |
curpos[i] = r->rorg[i]; |
| 430 |
if (r->rdir[i] > 1e-7) |
| 431 |
sflags |= 1 << i; |
| 432 |
else if (r->rdir[i] < -1e-7) |
| 433 |
sflags |= 0x10 << i; |
| 434 |
} |
| 435 |
if (sflags == 0) |
| 436 |
error(CONSISTENCY, "zero ray direction in localhit"); |
| 437 |
/* start off assuming nothing hit */ |
| 438 |
if (r->rmax > FTINY) { /* except aft plane if one */ |
| 439 |
r->ro = &Aftplane; |
| 440 |
r->rot = r->rmax; |
| 441 |
for (i = 0; i < 3; i++) |
| 442 |
r->rop[i] = r->rorg[i] + r->rot*r->rdir[i]; |
| 443 |
} |
| 444 |
/* find global cube entrance point */ |
| 445 |
t = 0.0; |
| 446 |
if (!incube(scene, curpos)) { |
| 447 |
/* find distance to entry */ |
| 448 |
for (i = 0; i < 3; i++) { |
| 449 |
/* plane in our direction */ |
| 450 |
if (sflags & 1<<i) |
| 451 |
dt = scene->cuorg[i]; |
| 452 |
else if (sflags & 0x10<<i) |
| 453 |
dt = scene->cuorg[i] + scene->cusize; |
| 454 |
else |
| 455 |
continue; |
| 456 |
/* distance to the plane */ |
| 457 |
dt = (dt - r->rorg[i])/r->rdir[i]; |
| 458 |
if (dt > t) |
| 459 |
t = dt; /* farthest face is the one */ |
| 460 |
} |
| 461 |
t += FTINY; /* fudge to get inside cube */ |
| 462 |
if (t >= r->rot) /* clipped already */ |
| 463 |
return(0); |
| 464 |
/* advance position */ |
| 465 |
for (i = 0; i < 3; i++) |
| 466 |
curpos[i] += r->rdir[i]*t; |
| 467 |
|
| 468 |
if (!incube(scene, curpos)) /* non-intersecting ray */ |
| 469 |
return(0); |
| 470 |
} |
| 471 |
cxset[0] = 0; |
| 472 |
raymove(curpos, cxset, sflags, r, scene); |
| 473 |
return(r->ro != NULL & r->ro != &Aftplane); |
| 474 |
} |
| 475 |
|
| 476 |
|
| 477 |
static int |
| 478 |
raymove(pos, cxs, dirf, r, cu) /* check for hit as we move */ |
| 479 |
FVECT pos; /* current position, modified herein */ |
| 480 |
OBJECT *cxs; /* checked objects, modified by checkhit */ |
| 481 |
int dirf; /* direction indicators to speed tests */ |
| 482 |
register RAY *r; |
| 483 |
register CUBE *cu; |
| 484 |
{ |
| 485 |
int ax; |
| 486 |
double dt, t; |
| 487 |
|
| 488 |
if (istree(cu->cutree)) { /* recurse on subcubes */ |
| 489 |
CUBE cukid; |
| 490 |
register int br, sgn; |
| 491 |
|
| 492 |
cukid.cusize = cu->cusize * 0.5; /* find subcube */ |
| 493 |
VCOPY(cukid.cuorg, cu->cuorg); |
| 494 |
br = 0; |
| 495 |
if (pos[0] >= cukid.cuorg[0]+cukid.cusize) { |
| 496 |
cukid.cuorg[0] += cukid.cusize; |
| 497 |
br |= 1; |
| 498 |
} |
| 499 |
if (pos[1] >= cukid.cuorg[1]+cukid.cusize) { |
| 500 |
cukid.cuorg[1] += cukid.cusize; |
| 501 |
br |= 2; |
| 502 |
} |
| 503 |
if (pos[2] >= cukid.cuorg[2]+cukid.cusize) { |
| 504 |
cukid.cuorg[2] += cukid.cusize; |
| 505 |
br |= 4; |
| 506 |
} |
| 507 |
for ( ; ; ) { |
| 508 |
cukid.cutree = octkid(cu->cutree, br); |
| 509 |
if ((ax = raymove(pos,cxs,dirf,r,&cukid)) == RAYHIT) |
| 510 |
return(RAYHIT); |
| 511 |
sgn = 1 << ax; |
| 512 |
if (sgn & dirf) /* positive axis? */ |
| 513 |
if (sgn & br) |
| 514 |
return(ax); /* overflow */ |
| 515 |
else { |
| 516 |
cukid.cuorg[ax] += cukid.cusize; |
| 517 |
br |= sgn; |
| 518 |
} |
| 519 |
else |
| 520 |
if (sgn & br) { |
| 521 |
cukid.cuorg[ax] -= cukid.cusize; |
| 522 |
br &= ~sgn; |
| 523 |
} else |
| 524 |
return(ax); /* underflow */ |
| 525 |
} |
| 526 |
/*NOTREACHED*/ |
| 527 |
} |
| 528 |
if (isfull(cu->cutree)) { |
| 529 |
if (checkhit(r, cu, cxs)) |
| 530 |
return(RAYHIT); |
| 531 |
} else if (r->ro == &Aftplane && incube(cu, r->rop)) |
| 532 |
return(RAYHIT); |
| 533 |
/* advance to next cube */ |
| 534 |
if (dirf&0x11) { |
| 535 |
dt = dirf&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0]; |
| 536 |
t = (dt - pos[0])/r->rdir[0]; |
| 537 |
ax = 0; |
| 538 |
} else |
| 539 |
t = FHUGE; |
| 540 |
if (dirf&0x22) { |
| 541 |
dt = dirf&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1]; |
| 542 |
dt = (dt - pos[1])/r->rdir[1]; |
| 543 |
if (dt < t) { |
| 544 |
t = dt; |
| 545 |
ax = 1; |
| 546 |
} |
| 547 |
} |
| 548 |
if (dirf&0x44) { |
| 549 |
dt = dirf&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2]; |
| 550 |
dt = (dt - pos[2])/r->rdir[2]; |
| 551 |
if (dt < t) { |
| 552 |
t = dt; |
| 553 |
ax = 2; |
| 554 |
} |
| 555 |
} |
| 556 |
pos[0] += r->rdir[0]*t; |
| 557 |
pos[1] += r->rdir[1]*t; |
| 558 |
pos[2] += r->rdir[2]*t; |
| 559 |
return(ax); |
| 560 |
} |
| 561 |
|
| 562 |
|
| 563 |
static |
| 564 |
checkhit(r, cu, cxs) /* check for hit in full cube */ |
| 565 |
register RAY *r; |
| 566 |
CUBE *cu; |
| 567 |
OBJECT *cxs; |
| 568 |
{ |
| 569 |
OBJECT oset[MAXSET+1]; |
| 570 |
register OBJREC *o; |
| 571 |
register int i; |
| 572 |
|
| 573 |
objset(oset, cu->cutree); |
| 574 |
checkset(oset, cxs); /* eliminate double-checking */ |
| 575 |
for (i = oset[0]; i > 0; i--) { |
| 576 |
o = objptr(oset[i]); |
| 577 |
if ((*ofun[o->otype].funp)(o, r)) |
| 578 |
r->robj = oset[i]; |
| 579 |
} |
| 580 |
if (r->ro == NULL) |
| 581 |
return(0); /* no scores yet */ |
| 582 |
|
| 583 |
return(incube(cu, r->rop)); /* hit OK if in current cube */ |
| 584 |
} |
| 585 |
|
| 586 |
|
| 587 |
static |
| 588 |
checkset(os, cs) /* modify checked set and set to check */ |
| 589 |
register OBJECT *os; /* os' = os - cs */ |
| 590 |
register OBJECT *cs; /* cs' = cs + os */ |
| 591 |
{ |
| 592 |
OBJECT cset[MAXCSET+MAXSET+1]; |
| 593 |
register int i, j; |
| 594 |
int k; |
| 595 |
/* copy os in place, cset <- cs */ |
| 596 |
cset[0] = 0; |
| 597 |
k = 0; |
| 598 |
for (i = j = 1; i <= os[0]; i++) { |
| 599 |
while (j <= cs[0] && cs[j] < os[i]) |
| 600 |
cset[++cset[0]] = cs[j++]; |
| 601 |
if (j > cs[0] || os[i] != cs[j]) { /* object to check */ |
| 602 |
os[++k] = os[i]; |
| 603 |
cset[++cset[0]] = os[i]; |
| 604 |
} |
| 605 |
} |
| 606 |
if (!(os[0] = k)) /* new "to check" set size */ |
| 607 |
return; /* special case */ |
| 608 |
while (j <= cs[0]) /* get the rest of cs */ |
| 609 |
cset[++cset[0]] = cs[j++]; |
| 610 |
if (cset[0] > MAXCSET) /* truncate "checked" set if nec. */ |
| 611 |
cset[0] = MAXCSET; |
| 612 |
/* setcopy(cs, cset); */ /* copy cset back to cs */ |
| 613 |
os = cset; |
| 614 |
for (i = os[0]; i-- >= 0; ) |
| 615 |
*cs++ = *os++; |
| 616 |
} |
