Merged branch 'dev_native' into lm_sla_supports_auto

Added igl library files

src/igl/biharmonic_coordinates.cpp

@@ -0,0 +1,203 @@
+// This file is part of libigl, a simple c++ geometry processing library.
+//
+// Copyright (C) 2015 Alec Jacobson <alecjacobson@gmail.com>
+//
+// This Source Code Form is subject to the terms of the Mozilla Public License
+// v. 2.0. If a copy of the MPL was not distributed with this file, You can
+// obtain one at http://mozilla.org/MPL/2.0/.
+#include "biharmonic_coordinates.h"
+#include "cotmatrix.h"
+#include "sum.h"
+#include "massmatrix.h"
+#include "min_quad_with_fixed.h"
+#include "crouzeix_raviart_massmatrix.h"
+#include "crouzeix_raviart_cotmatrix.h"
+#include "normal_derivative.h"
+#include "on_boundary.h"
+#include <Eigen/Sparse>
+
+template <
+  typename DerivedV,
+  typename DerivedT,
+  typename SType,
+  typename DerivedW>
+IGL_INLINE bool igl::biharmonic_coordinates(
+  const Eigen::PlainObjectBase<DerivedV> & V,
+  const Eigen::PlainObjectBase<DerivedT> & T,
+  const std::vector<std::vector<SType> > & S,
+  Eigen::PlainObjectBase<DerivedW> & W)
+{
+  return biharmonic_coordinates(V,T,S,2,W);
+}
+
+template <
+  typename DerivedV,
+  typename DerivedT,
+  typename SType,
+  typename DerivedW>
+IGL_INLINE bool igl::biharmonic_coordinates(
+  const Eigen::PlainObjectBase<DerivedV> & V,
+  const Eigen::PlainObjectBase<DerivedT> & T,
+  const std::vector<std::vector<SType> > & S,
+  const int k,
+  Eigen::PlainObjectBase<DerivedW> & W)
+{
+  using namespace Eigen;
+  using namespace std;
+  // This is not the most efficient way to build A, but follows "Linear
+  // Subspace Design for Real-Time Shape Deformation" [Wang et al. 2015].
+  SparseMatrix<double> A;
+  {
+    DiagonalMatrix<double,Dynamic> Minv;
+    SparseMatrix<double> L,K;
+    Array<bool,Dynamic,Dynamic> C;
+    {
+      Array<bool,Dynamic,1> I;
+      on_boundary(T,I,C);
+    }
+#ifdef false 
+    // Version described in paper is "wrong"
+    // http://www.cs.toronto.edu/~jacobson/images/error-in-linear-subspace-design-for-real-time-shape-deformation-2017-wang-et-al.pdf
+    SparseMatrix<double> N,Z,M;
+    normal_derivative(V,T,N);
+    {
+      std::vector<Triplet<double> >ZIJV;
+      for(int t =0;t<T.rows();t++)
+      {
+        for(int f =0;f<T.cols();f++)
+        {
+          if(C(t,f))
+          {
+            const int i = t+f*T.rows();
+            for(int c = 1;c<T.cols();c++)
+            {
+              ZIJV.emplace_back(T(t,(f+c)%T.cols()),i,1);
+            }
+          }
+        }
+      }
+      Z.resize(V.rows(),N.rows());
+      Z.setFromTriplets(ZIJV.begin(),ZIJV.end());
+      N = (Z*N).eval();
+    }
+    cotmatrix(V,T,L);
+    K = N+L;
+    massmatrix(V,T,MASSMATRIX_TYPE_DEFAULT,M);
+    // normalize
+    M /= ((VectorXd)M.diagonal()).array().abs().maxCoeff();
+    Minv =
+      ((VectorXd)M.diagonal().array().inverse()).asDiagonal();
+#else
+    Eigen::SparseMatrix<double> M;
+    Eigen::MatrixXi E;
+    Eigen::VectorXi EMAP;
+    crouzeix_raviart_massmatrix(V,T,M,E,EMAP);
+    crouzeix_raviart_cotmatrix(V,T,E,EMAP,L);
+    // Ad  #E by #V facet-vertex incidence matrix
+    Eigen::SparseMatrix<double> Ad(E.rows(),V.rows());
+    {
+      std::vector<Eigen::Triplet<double> > AIJV(E.size());
+      for(int e = 0;e<E.rows();e++)
+      {
+        for(int c = 0;c<E.cols();c++)
+        {
+          AIJV[e+c*E.rows()] = Eigen::Triplet<double>(e,E(e,c),1);
+        }
+      }
+      Ad.setFromTriplets(AIJV.begin(),AIJV.end());
+    }
+    // Degrees
+    Eigen::VectorXd De;
+    sum(Ad,2,De);
+    Eigen::DiagonalMatrix<double,Eigen::Dynamic> De_diag = 
+      De.array().inverse().matrix().asDiagonal();
+    K = L*(De_diag*Ad);
+    // normalize
+    M /= ((VectorXd)M.diagonal()).array().abs().maxCoeff();
+    Minv = ((VectorXd)M.diagonal().array().inverse()).asDiagonal();
+    // kill boundary edges
+    for(int f = 0;f<T.rows();f++)
+    {
+      for(int c = 0;c<T.cols();c++)
+      {
+        if(C(f,c))
+        {
+          const int e = EMAP(f+T.rows()*c);
+          Minv.diagonal()(e) = 0;
+        }
+      }
+    }
+
+#endif
+    switch(k)
+    {
+      default:
+        assert(false && "unsupported");
+      case 2:
+        // For C1 smoothness in 2D, one should use bi-harmonic
+        A = K.transpose() * (Minv * K);
+        break;
+      case 3:
+        // For C1 smoothness in 3D, one should use tri-harmonic
+        A = K.transpose() * (Minv * (-L * (Minv * K)));
+        break;
+    }
+  }
+  // Vertices in point handles
+  const size_t mp =
+    count_if(S.begin(),S.end(),[](const vector<int> & h){return h.size()==1;});
+  // number of region handles
+  const size_t r = S.size()-mp;
+  // Vertices in region handles
+  size_t mr = 0;
+  for(const auto & h : S)
+  {
+    if(h.size() > 1)
+    {
+      mr += h.size();
+    }
+  }
+  const size_t dim = T.cols()-1;
+  // Might as well be dense... I think...
+  MatrixXd J = MatrixXd::Zero(mp+mr,mp+r*(dim+1));
+  VectorXi b(mp+mr);
+  MatrixXd H(mp+r*(dim+1),dim);
+  {
+    int v = 0;
+    int c = 0;
+    for(int h = 0;h<S.size();h++)
+    {
+      if(S[h].size()==1)
+      {
+        H.row(c) = V.block(S[h][0],0,1,dim);
+        J(v,c++) = 1;
+        b(v) = S[h][0];
+        v++;
+      }else
+      {
+        assert(S[h].size() >= dim+1);
+        for(int p = 0;p<S[h].size();p++)
+        {
+          for(int d = 0;d<dim;d++)
+          {
+            J(v,c+d) = V(S[h][p],d);
+          }
+          J(v,c+dim) = 1;
+          b(v) = S[h][p];
+          v++;
+        }
+        H.block(c,0,dim+1,dim).setIdentity();
+        c+=dim+1;
+      }
+    }
+  }
+  // minimize    ½ W' A W'
+  // subject to  W(b,:) = J
+  return min_quad_with_fixed(
+    A,VectorXd::Zero(A.rows()).eval(),b,J,SparseMatrix<double>(),VectorXd(),true,W);
+}
+
+#ifdef IGL_STATIC_LIBRARY
+// Explicit template instantiation
+template bool igl::biharmonic_coordinates<Eigen::Matrix<double, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, -1, 0, -1, -1>, int, Eigen::Matrix<double, -1, -1, 0, -1, -1> >(Eigen::PlainObjectBase<Eigen::Matrix<double, -1, -1, 0, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> > const&, std::vector<std::vector<int, std::allocator<int> >, std::allocator<std::vector<int, std::allocator<int> > > > const&, int, Eigen::PlainObjectBase<Eigen::Matrix<double, -1, -1, 0, -1, -1> >&);
+#endif