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#ifndef lint
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static const char RCSid[] = "$Id: o_instance.c,v 2.8 2004/03/30 16:13:01 schorsch Exp $";
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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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#include "copyright.h"
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#include "ray.h"
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#include "instance.h"
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#include "rtotypes.h"
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int
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o_instance( /* compute ray intersection with octree */
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OBJREC *o,
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RAY *r
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)
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{
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RAY rcont;
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double d;
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INSTANCE *ins;
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int i;
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/* get the octree */
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ins = getinstance(o, IO_ALL);
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/* copy and transform ray */
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rcont = *r;
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multp3(rcont.rorg, r->rorg, ins->x.b.xfm);
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multv3(rcont.rdir, r->rdir, ins->x.b.xfm);
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for (i = 0; i < 3; i++)
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rcont.rdir[i] /= ins->x.b.sca;
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rcont.rmax *= ins->x.b.sca;
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/* clear and trace it */
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rayclear(&rcont);
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if (!localhit(&rcont, &ins->obj->scube))
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return(0); /* missed */
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if (rcont.rot * ins->x.f.sca >= r->rot)
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return(0); /* not close enough */
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if (o->omod != OVOID) { /* if we have modifier, use it */
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r->ro = o;
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r->rox = NULL;
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} else { /* else use theirs */
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r->ro = rcont.ro;
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if (rcont.rox != NULL) {
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newrayxf(r); /* allocate transformation */
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/* NOTE: r->rox may equal rcont.rox! */
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multmat4(r->rox->f.xfm, rcont.rox->f.xfm, ins->x.f.xfm);
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r->rox->f.sca = rcont.rox->f.sca * ins->x.f.sca;
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multmat4(r->rox->b.xfm, ins->x.b.xfm, rcont.rox->b.xfm);
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r->rox->b.sca = ins->x.b.sca * rcont.rox->b.sca;
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} else
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r->rox = &ins->x;
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}
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/* transform it back */
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r->rot = rcont.rot * ins->x.f.sca;
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multp3(r->rop, rcont.rop, ins->x.f.xfm);
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multv3(r->ron, rcont.ron, ins->x.f.xfm);
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multv3(r->pert, rcont.pert, ins->x.f.xfm);
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d = 1./ins->x.f.sca;
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for (i = 0; i < 3; i++) {
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r->ron[i] *= d;
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r->pert[i] *= d;
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}
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r->rod = rcont.rod;
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r->uv[0] = rcont.uv[0];
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r->uv[1] = rcont.uv[1];
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/* return hit */
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return(1);
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}
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