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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, IO_ALL); | 
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                                        /* copy old ray */ | 
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        copystruct(&rcont, r); | 
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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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        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 (o->omod != OVOID) {         /* if we have modifier, use it */ | 
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                r->ro = o; | 
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                r->rofs = 1.0; setident4(r->rofx); | 
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                r->robs = 1.0; setident4(r->robx); | 
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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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} |