IGL_INLINE void igl::peal_outer_hull_layers(
const Eigen::PlainObjectBase<DerivedV > & V,
const Eigen::PlainObjectBase<DerivedF > & F,
Eigen::PlainObjectBase<Derivedodd > & odd,
Eigen::PlainObjectBase<Derivedflip > & flip)
{
using namespace Eigen;
using namespace std;
typedef typename DerivedF::Index Index;
typedef Matrix<typename DerivedF::Scalar,Dynamic,DerivedF::ColsAtCompileTime> MatrixXF;
typedef Matrix<Index,Dynamic,1> MatrixXI;
typedef Matrix<typename Derivedflip::Scalar,Dynamic,Derivedflip::ColsAtCompileTime> MatrixXflip;
const Index m = F.rows();
#ifdef IGL_PEAL_OUTER_HULL_LAYERS_DEBUG
cout<<"peal outer hull layers..."<<endl;
#endif
#ifdef IGL_PEAL_OUTER_HULL_LAYERS_DEBUG
cout<<"resize output ..."<<endl;
#endif
// keep track of iteration parity and whether flipped in hull
MatrixXF Fr = F;
odd.resize(m,1);
flip.resize(m,1);
// Keep track of index map
MatrixXI IM = MatrixXI::LinSpaced(m,0,m-1);
// This is O(n * layers)
bool odd_iter = true;
MatrixXI P(m,1);
Index iter = 0;
while(Fr.size() > 0)
{
assert(Fr.rows() == IM.rows());
// Compute outer hull of current Fr
MatrixXF Fo;
MatrixXI Jo;
MatrixXflip flipr;
#ifdef IGL_PEAL_OUTER_HULL_LAYERS_DEBUG
cout<<"calling outer hull..."<<endl;
writePLY("outer-hull-input.ply",V,Fr);
#endif
outer_hull(V,Fr,Fo,Jo,flipr);
#ifdef IGL_PEAL_OUTER_HULL_LAYERS_DEBUG
cout<<"reindex, flip..."<<endl;
#endif
assert(Fo.rows() == Jo.rows());
// all faces in Fo of Fr
vector<bool> in_outer(Fr.rows(),false);
for(Index g = 0;g<Jo.rows();g++)
{
odd(IM(Jo(g))) = odd_iter;
P(IM(Jo(g))) = iter;
in_outer[Jo(g)] = true;
flip(IM(Jo(g))) = flipr(Jo(g));
}
// Fr = Fr - Fo
// update IM
MatrixXF prev_Fr = Fr;
MatrixXI prev_IM = IM;
Fr.resize(prev_Fr.rows() - Fo.rows(),F.cols());
IM.resize(Fr.rows());
{
Index g = 0;
for(Index f = 0;f<prev_Fr.rows();f++)
{
if(!in_outer[f])
{
Fr.row(g) = prev_Fr.row(f);
IM(g) = prev_IM(f);
g++;
}
}
}
odd_iter = !odd_iter;
iter++;
}
}
