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/* Copyright (c) 1988 Regents of the University of California */
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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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* o_instance.c - routines for computing ray intersections with octrees.
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*
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* 11/11/88
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*/
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#include "ray.h"
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#include "instance.h"
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o_instance(o, r) /* compute ray intersection with octree */
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OBJREC *o;
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register RAY *r;
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{
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extern long nrays;
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RAY rcont;
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register INSTANCE *in;
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register int i;
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/* get the octree */
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in = getinstance(o, GET_ALL);
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/* copy old ray */
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bcopy(r, &rcont, sizeof(RAY));
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/* transform it */
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rcont.rno = nrays;
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rcont.ro = NULL;
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rcont.rot = FHUGE;
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rcont.rno = nrays;
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multp3(rcont.rorg, r->rorg, in->b.xfm);
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multv3(rcont.rdir, r->rdir, in->b.xfm);
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for (i = 0; i < 3; i++)
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rcont.rdir[i] /= in->b.sca;
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/* trace it */
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if (!localhit(&rcont, &in->obj->scube))
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return(0); /* missed */
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if (rcont.rot * in->f.sca >= r->rot)
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return(0); /* not close enough */
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/* if we have modifier, use it */
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if (o->omod != OVOID)
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r->ro = o;
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else { /* else use theirs */
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r->ro = rcont.ro;
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multmat4(r->rofx, rcont.rofx, in->f.xfm);
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r->rofs = rcont.rofs * in->f.sca;
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multmat4(r->robx, in->b.xfm, rcont.robx);
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r->robs = in->b.sca * rcont.robs;
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}
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/* transform it back */
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r->rot = rcont.rot * in->f.sca;
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multp3(r->rop, rcont.rop, in->f.xfm);
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multv3(r->ron, rcont.ron, in->f.xfm);
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for (i = 0; i < 3; i++)
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r->ron[i] /= in->f.sca;
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r->rod = rcont.rod;
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/* return hit */
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return(1);
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}
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