void dual(Manifold& m)
{
// Create new vertices. Each face becomes a vertex whose position
// is the centre of the face
int i = 0;
FaceAttributeVector<int> ftouched;
vector<Vec3d> vertices;
vertices.resize(m.no_faces());
for(auto f : m.faces())
vertices[ftouched[f] = i++] = centre(m, f);
// Create new faces. Each vertex is a new face with N=valency of vertex
// edges.
vector<int> faces;
vector<int> indices;
for(auto v : m.vertices())
if(valency(m, v) > 2 && !(boundary(m, v)))
{
// int N = circulate_vertex_ccw(m, v, (std::function<void(FaceID)>)[&](FaceID fid) {
// indices.push_back(ftouched[fid]);
// });
Walker w = m.walker(v);
for(; !w.full_circle(); w = w.circulate_vertex_ccw()){
indices.push_back(ftouched[w.face()]);
}
int N = w.no_steps();
// Insert face valency in the face vector.
faces.push_back(N);
}
// Clear the manifold before new geometry is inserted.
m.clear();
// And build
m.build( vertices.size(),
reinterpret_cast<double*>(&vertices[0]),
faces.size(),
&faces[0],
&indices[0]);
}
