/* Find vertices completing triangles on either side of the given edge */
int
get_triangles(RBFNODE *rbfv[2], const MIGRATION *mig)
{
const MIGRATION *ej1, *ej2;
RBFNODE *tv;
rbfv[0] = rbfv[1] = NULL;
if (mig == NULL)
return(0);
for (ej1 = mig->rbfv[0]->ejl; ej1 != NULL;
ej1 = nextedge(mig->rbfv[0],ej1)) {
if (ej1 == mig)
continue;
tv = opp_rbf(mig->rbfv[0],ej1);
for (ej2 = tv->ejl; ej2 != NULL; ej2 = nextedge(tv,ej2))
if (opp_rbf(tv,ej2) == mig->rbfv[1]) {
rbfv[is_rev_tri(mig->rbfv[0]->invec,
mig->rbfv[1]->invec,
tv->invec)] = tv;
break;
}
}
return((rbfv[0] != NULL) + (rbfv[1] != NULL));
}
/* Check if prospective vertex would create overlapping triangle */
static int
overlaps_tri(const RBFNODE *bv0, const RBFNODE *bv1, const RBFNODE *pv)
{
const MIGRATION *ej;
RBFNODE *vother[2];
int im_rev;
/* find shared edge in mesh */
for (ej = pv->ejl; ej != NULL; ej = nextedge(pv,ej)) {
const RBFNODE *tv = opp_rbf(pv,ej);
if (tv == bv0) {
im_rev = is_rev_tri(ej->rbfv[0]->invec,
ej->rbfv[1]->invec, bv1->invec);
break;
}
if (tv == bv1) {
im_rev = is_rev_tri(ej->rbfv[0]->invec,
ej->rbfv[1]->invec, bv0->invec);
break;
}
}
if (!get_triangles(vother, ej)) /* triangle on same side? */
return(0);
return(vother[im_rev] != NULL);
}
