bool
Bface::get_quad_verts(Bvert*& a, Bvert*& b, Bvert*& c, Bvert*& d) const
{
// Return CCW verts a, b, c, d as in the picture, orienting
// things so that the weak edge runs NE as shown:
//
// d ---------- c = w->v2() ^
// | / | |
// | / | |
// | w / | tan1 tan2 |
// | / | --------> |
// | / f | |
// |/ |
// a ---------- b
// = w->v1()
//
if (!is_quad())
return 0;
Bedge* w = weak_edge();
Bface* f = w->ccw_face(w->v2());
a = w->v1();
b = f->next_vert_ccw(a);
c = w->v2();
d = f->quad_vert();
return true;
}
void
EdgeStrip::build_ccw_boundaries(
CBedge_list& edges,
CSimplexFilter& face_filter
)
{
// Similar to previous...
//
// XXX - needs comments
// Clear edge flags to screen for unreached edges:
// set edge flags to 1 in 1-ring of verts,
// then clear edge flags of internal edges
set_adjacent_edges(edges.get_verts(), 1);
edges.clear_flags();
// get an edge filter that accepts "boundary" edges WRT the
// given face filter
BoundaryEdgeFilter boundary(face_filter);
// Pull out the edge tips:
Bedge_list tips = edges.filter(ChainTipEdgeFilter(boundary));
// Construct the filter that screens out previously reached
// edges:
UnreachedSimplexFilter unreached;
AndFilter wanted = unreached + boundary;
int k;
// Start from all the tips first:
for (k=0; k<tips.num(); k++) {
Bedge* e = tips[k];
Bvert* v = (e->v2()->degree(boundary) != 2) ? e->v2() : e->v1();
Bface* f = e->screen_face(face_filter);
assert(f); // e must have 1 face satisfying the filter
// If this will start out running ccw, take it.
// otherwise skip:
if (f->next_vert_ccw(v) == e->other_vertex(v))
build(v, e, wanted);
}
// Now check the rest:
for (k=0; k<edges.num(); k++) {
Bedge* e = edges[k];
Bface* f = e->screen_face(face_filter);
assert(f); // e must have 1 face satisfying the filter
// Go CCW around faces
build(f->leading_vert_ccw(e), e, wanted);
}
}
