extern int
o_instance( /* compute ray intersection with octree */
OBJREC *o,
register RAY *r
)
{
RAY rcont;
double d;
register INSTANCE *ins;
register int i;
/* get the octree */
ins = getinstance(o, IO_ALL);
/* copy and transform ray */
rcont = *r;
multp3(rcont.rorg, r->rorg, ins->x.b.xfm);
multv3(rcont.rdir, r->rdir, ins->x.b.xfm);
for (i = 0; i < 3; i++)
rcont.rdir[i] /= ins->x.b.sca;
rcont.rmax *= ins->x.b.sca;
/* clear and trace it */
rayclear(&rcont);
if (!localhit(&rcont, &ins->obj->scube))
return(0); /* missed */
if (rcont.rot * ins->x.f.sca >= r->rot)
return(0); /* not close enough */
if (o->omod != OVOID) { /* if we have modifier, use it */
r->ro = o;
r->rox = NULL;
} else { /* else use theirs */
r->ro = rcont.ro;
if (rcont.rox != NULL) {
newrayxf(r); /* allocate transformation */
/* NOTE: r->rox may equal rcont.rox! */
multmat4(r->rox->f.xfm, rcont.rox->f.xfm, ins->x.f.xfm);
r->rox->f.sca = rcont.rox->f.sca * ins->x.f.sca;
multmat4(r->rox->b.xfm, ins->x.b.xfm, rcont.rox->b.xfm);
r->rox->b.sca = ins->x.b.sca * rcont.rox->b.sca;
} else
r->rox = &ins->x;
}
/* transform it back */
r->rot = rcont.rot * ins->x.f.sca;
multp3(r->rop, rcont.rop, ins->x.f.xfm);
multv3(r->ron, rcont.ron, ins->x.f.xfm);
multv3(r->pert, rcont.pert, ins->x.f.xfm);
d = 1./ins->x.f.sca;
for (i = 0; i < 3; i++) {
r->ron[i] *= d;
r->pert[i] *= d;
}
r->rod = rcont.rod;
r->uv[0] = rcont.uv[0];
r->uv[1] = rcont.uv[1];
/* return hit */
return(1);
}
int
xf_handler(int ac, char **av) /* handle xf entity */
{
register XF_SPEC *spec;
register int n;
int rv;
if (ac == 1) { /* something with existing transform */
if ((spec = xf_context) == NULL)
return(MG_ECNTXT);
n = -1;
if (spec->xarr != NULL) { /* check for iteration */
register struct xf_array *ap = spec->xarr;
(void)xf_aname((struct xf_array *)NULL);
n = ap->ndim;
while (n--) {
if (++ap->aarg[n].i < ap->aarg[n].n)
break;
(void)strcpy(ap->aarg[n].arg, "0");
ap->aarg[n].i = 0;
}
if (n >= 0) {
if ((rv = mg_fgoto(&ap->spos)) != MG_OK)
return(rv);
sprintf(ap->aarg[n].arg, "%d", ap->aarg[n].i);
(void)xf_aname(ap);
}
}
if (n < 0) { /* pop transform */
xf_context = spec->prev;
free_xf(spec);
return(MG_OK);
}
} else { /* else allocate transform */
if ((spec = new_xf(ac-1, av+1)) == NULL)
return(MG_EMEM);
if (spec->xarr != NULL)
(void)xf_aname(spec->xarr);
spec->prev = xf_context; /* push onto stack */
xf_context = spec;
}
/* translate new specification */
n = xf_ac(spec);
n -= xf_ac(spec->prev); /* incremental comp. is more eff. */
if (xf(&spec->xf, n, xf_av(spec)) != n)
return(MG_ETYPE);
/* check for vertex reversal */
if ((spec->rev = (spec->xf.sca < 0.)))
spec->xf.sca = -spec->xf.sca;
/* compute total transformation */
if (spec->prev != NULL) {
multmat4(spec->xf.xfm, spec->xf.xfm, spec->prev->xf.xfm);
spec->xf.sca *= spec->prev->xf.sca;
spec->rev ^= spec->prev->rev;
}
spec->xid = comp_xfid(spec->xf.xfm); /* compute unique ID */
return(MG_OK);
}
