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_with_tips(CBedge_list& edges, CSimplexFilter& filter)
{
// Build the strip from the given pool of edges, with the
// given filter. Try to start the edge strip at the "tips" of
// chains of edges of the desired type. The given filter
// should just screen for edges of the desired kind;
// internally this method also screens for edges that have not
// yet been reached (added to the strip).
// Clear edge flags to screen for unreached edges:
set_adjacent_edges(edges.get_verts(), 1);
edges.clear_flags();
// Pull out the edge tips:
Bedge_list tips = edges.filter(ChainTipEdgeFilter(filter));
// Construct the filter that screens out previously reached
// edges:
UnreachedSimplexFilter unreached;
AndFilter wanted = unreached + filter;
int k;
// Start from all the tips first:
for (k=0; k<tips.num(); k++) {
Bedge* e = tips[k];
Bvert* v = (e->v2()->degree(filter) != 2) ? e->v2() : e->v1();
build(v, e, wanted);
}
// Now check the rest:
for (k=0; k<edges.num(); k++)
build(0, edges[k], wanted);
}
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);
}
}
void
Lface::allocate_subdiv_elements()
{
// Generate 4 faces and 3 internal edges
// in the subdivision mesh next level down.
// NOTE: The specific order that sub-faces are created,
// and the order of the vertices used in creating them,
// should not be changed. The barycentric coordinate
// conversion routines (below) depend on these orderings.
// Make this lightweight, so you can call
// it when you're not sure if you need to:
if (is_set(SUBDIV_ALLOCATED_BIT))
return;
set_bit(SUBDIV_ALLOCATED_BIT);
assert(lmesh() != nullptr);
lmesh()->allocate_subdiv_mesh();
LMESHptr submesh = lmesh()->subdiv_mesh();
assert(submesh != nullptr);
// lv3 #
// /\ #
// /3 \ #
// / \ #
// / \ #
// / child3 \ #
// / \ #
// / 1 2 \ #
// le3 /______________\ le2 #
// /\ 2 1 /\ #
// /3 \ /3 \ #
// / \ center / \ #
// / \ child / \ #
// / \ / \ #
// / child1 \ / child2 \ #
// / \3 / \ #
// / 1 2 \/ 1 2 \ #
// lv1 -------------------------------- lv2 #
// le1 #
// Make sure subdiv elements have
// been allocated around face boundary:
lv(1)->allocate_subdiv_vert();
lv(2)->allocate_subdiv_vert();
lv(3)->allocate_subdiv_vert();
le(1)->allocate_subdiv_elements();
le(2)->allocate_subdiv_elements();
le(3)->allocate_subdiv_elements();
Patch* child_patch = _patch ? _patch->get_child() : nullptr;
// hook up 4 faces (verifying they're not already there):
if (!subdiv_face1())
gen_child_face(
lv(1)->subdiv_vertex(),
le(1)->subdiv_vertex(),
le(3)->subdiv_vertex(),
child_patch, submesh);
if (!subdiv_face2())
gen_child_face(
le(1)->subdiv_vertex(),
lv(2)->subdiv_vertex(),
le(2)->subdiv_vertex(),
child_patch, submesh);
if (!subdiv_face3())
gen_child_face(
le(3)->subdiv_vertex(),
le(2)->subdiv_vertex(),
lv(3)->subdiv_vertex(),
child_patch, submesh);
if (!subdiv_face_center())
gen_child_face(
le(2)->subdiv_vertex(),
le(3)->subdiv_vertex(),
le(1)->subdiv_vertex(),
child_patch, submesh, true); // true: face is at center
if (is_quad()) {
//
// o
// | .
// | .
// | . w
// | .
// sub1 o .----- o.
// | . | .
// | . | .
// | .| .
// o ------ o ----- o
// v sub2
//
// A quad face is one that has a "weak" edge
// (shown as the dotted edge labelled 'w' above).
// A weak edge is considered to be the internal
// diagonal edge of a quad, with this face making
// up one half of the quad and the face on the
// other side (not shown) making up the other
// half. In subdivision we label the subdivision
// edges accordingly. I.e. the edge connecting
// subdivision vertices sub1 and sub2 should be
// labelled weak.
Bedge* w = weak_edge();
Bvert* v = other_vertex(w);
Bvert* sub1 = ((Ledge*)v->lookup_edge(w->v1()))->subdiv_vertex();
Bvert* sub2 = ((Ledge*)v->lookup_edge(w->v2()))->subdiv_vertex();
sub1->lookup_edge(sub2)->set_bit(Bedge::WEAK_BIT);
}
// Now that child faces are generated, propagate multi
// status (if any) to children
le(1)->push_multi(this);
le(2)->push_multi(this);
le(3)->push_multi(this);
// Notify observers:
if (_data_list)
_data_list->notify_subdiv_gen();
}