tetra smooth

This commit is contained in:
T.Alderighi 2018-05-23 17:51:20 +02:00
parent d2dd2d01f0
commit 81a93f7756
4 changed files with 960 additions and 446 deletions

View File

@ -217,25 +217,24 @@ class Smooth
//if we are applying to a tetrahedral mesh: //if we are applying to a tetrahedral mesh:
ForEachTetra(m, [&](TetraType &t) { ForEachTetra(m, [&](TetraType &t) {
for (int i = 0; i < 4; ++i) for (int i = 0; i < 6; ++i)
if (!t.IsB(i))
{ {
VertexPointer v0, v1, v2; VertexPointer v0, v1, vo0, vo1;
v0 = t.V(Tetra::VofF(i, 0)); v0 = t.V(Tetra::VofE(i, 0));
v1 = t.V(Tetra::VofF(i, 1)); v1 = t.V(Tetra::VofE(i, 1));
v2 = t.V(Tetra::VofF(i, 2));
TD[v0].sum += v1->P() * weight; vo0 = t.V(Tetra::VofE(5 - i, 0));
TD[v0].sum += v2->P() * weight; vo1 = t.V(Tetra::VofE(5 - i, 1));
TD[v0].cnt += 2 * weight;
TD[v1].sum += v0->P() * weight; ScalarType angle = Tetra::DihedralAngle(t, 5 - i);
TD[v1].sum += v2->P() * weight; ScalarType length = vcg::Distance(vo0->P(), vo1->P());
TD[v1].cnt += 2 * weight;
TD[v2].sum += v0->P() * weight; weight = (length / 6.) * (tan(M_PI / 2. - angle));
TD[v2].sum += v1->P() * weight;
TD[v2].cnt += 2 * weight; TD[v0].sum += v1->cP() * weight;
TD[v1].sum += v0->cP() * weight;
TD[v0].cnt += weight;
TD[v1].cnt += weight;
} }
}); });
@ -258,28 +257,28 @@ class Smooth
} }
}); });
ForEachTetra(m, [&](TetraType &t) { // ForEachTetra(m, [&](TetraType &t) {
for (int i = 0; i < 4; ++i) // for (int i = 0; i < 4; ++i)
if (t.IsB(i)) // if (t.IsB(i))
{ // {
VertexPointer v0, v1, v2; // VertexPointer v0, v1, v2;
v0 = t.V(Tetra::VofF(i, 0)); // v0 = t.V(Tetra::VofF(i, 0));
v1 = t.V(Tetra::VofF(i, 1)); // v1 = t.V(Tetra::VofF(i, 1));
v2 = t.V(Tetra::VofF(i, 2)); // v2 = t.V(Tetra::VofF(i, 2));
TD[v0].sum += v1->P() * weight; // TD[v0].sum += v1->P();
TD[v0].sum += v2->P() * weight; // TD[v0].sum += v2->P();
TD[v0].cnt += 2 * weight; // TD[v0].cnt += 2;
TD[v1].sum += v0->P() * weight; // TD[v1].sum += v0->P();
TD[v1].sum += v2->P() * weight; // TD[v1].sum += v2->P();
TD[v1].cnt += 2 * weight; // TD[v1].cnt += 2;
TD[v2].sum += v0->P() * weight; // TD[v2].sum += v0->P();
TD[v2].sum += v1->P() * weight; // TD[v2].sum += v1->P();
TD[v2].cnt += 2 * weight; // TD[v2].cnt += 2;
} // }
}); // });
FaceIterator fi; FaceIterator fi;
for (fi = m.face.begin(); fi != m.face.end(); ++fi) for (fi = m.face.begin(); fi != m.face.end(); ++fi)

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@ -0,0 +1,495 @@
/****************************************************************************
* VCGLib o o *
* Visual and Computer Graphics Library o o *
* _ O _ *
* Copyright(C) 2004-2016 \/)\/ *
* Visual Computing Lab /\/| *
* ISTI - Italian National Research Council | *
* \ *
* All rights reserved. *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License (http://www.gnu.org/licenses/gpl.txt) *
* for more details. *
* *
****************************************************************************/
#ifndef __VCG_IMPLICIT_TETRA_SMOOTHER
#define __VCG_IMPLICIT_TETRA_SMOOTHER
#include <Eigen/Sparse>
#include <vcg/complex/algorithms/mesh_to_matrix.h>
#include <vcg/complex/algorithms/update/quality.h>
#include <vcg/complex/algorithms/smooth.h>
#define PENALTY 10000
namespace vcg
{
template <class MeshType>
class ImplicitTetraSmoother
{
typedef typename MeshType::FaceType FaceType;
typedef typename MeshType::VertexType VertexType;
typedef typename MeshType::TetraType TetraType;
typedef typename MeshType::CoordType CoordType;
typedef typename MeshType::ScalarType ScalarType;
typedef typename Eigen::Matrix<ScalarType, Eigen::Dynamic, Eigen::Dynamic> MatrixXm;
public:
struct FaceConstraint
{
int numF;
std::vector<ScalarType> BarycentricW;
CoordType TargetPos;
FaceConstraint()
{
numF = -1;
}
FaceConstraint(int _numF,
const std::vector<ScalarType> &_BarycentricW,
const CoordType &_TargetPos)
{
numF = _numF;
BarycentricW = std::vector<ScalarType>(_BarycentricW.begin(), _BarycentricW.end());
TargetPos = _TargetPos;
}
};
struct Parameter
{
//the amount of smoothness, useful only if we set the mass matrix
ScalarType lambda;
//the use of mass matrix to keep the mesh close to its original position
//(weighted per area distributed on vertices)
bool useMassMatrix;
//this bool is used to fix the border vertices of the mesh or not
bool fixBorder;
//this bool is used to set if cotangent weight is used, this flag to false means uniform laplacian
bool useCotWeight;
//use this weight for the laplacian when the cotangent one is not used
ScalarType lapWeight;
//the set of fixed vertices
std::vector<int> FixedV;
//the set of faces for barycentric constraints
std::vector<FaceConstraint> ConstrainedF;
//the degree of laplacian
int degree;
//this is to say if we smooth the positions or the quality
bool SmoothQ;
Parameter()
{
degree = 2;
lambda = 0.05;
useMassMatrix = true;
fixBorder = true;
useCotWeight = false;
lapWeight = 1;
SmoothQ = false;
}
};
private:
static void InitSparse(const std::vector<std::pair<int, int>> &Index,
const std::vector<ScalarType> &Values,
const int m,
const int n,
Eigen::SparseMatrix<ScalarType> &X)
{
assert(Index.size() == Values.size());
std::vector<Eigen::Triplet<ScalarType>> IJV;
IJV.reserve(Index.size());
for (size_t i = 0; i < Index.size(); i++)
{
int row = Index[i].first;
int col = Index[i].second;
ScalarType val = Values[i];
assert(row < m);
assert(col < n);
IJV.push_back(Eigen::Triplet<ScalarType>(row, col, val));
}
X.resize(m, n);
X.setFromTriplets(IJV.begin(), IJV.end());
}
static void CollectHardConstraints(MeshType &mesh, const Parameter &SParam,
std::vector<std::pair<int, int>> &IndexC,
std::vector<ScalarType> &WeightC,
bool SmoothQ = false)
{
std::vector<int> To_Fix;
//collect fixed vert
if (SParam.fixBorder)
{
//add penalization constra
for (size_t i = 0; i < mesh.vert.size(); i++)
{
if (!mesh.vert[i].IsB())
continue;
To_Fix.push_back(i);
}
}
//add additional fixed vertices constraint
To_Fix.insert(To_Fix.end(), SParam.FixedV.begin(), SParam.FixedV.end());
//sort and make them unique
std::sort(To_Fix.begin(), To_Fix.end());
typename std::vector<int>::iterator it = std::unique(To_Fix.begin(), To_Fix.end());
To_Fix.resize(std::distance(To_Fix.begin(), it));
for (size_t i = 0; i < To_Fix.size(); i++)
{
if (!SmoothQ)
{
for (int j = 0; j < 3; j++)
{
int IndexV = (To_Fix[i] * 3) + j;
IndexC.push_back(std::pair<int, int>(IndexV, IndexV));
WeightC.push_back((ScalarType)PENALTY);
}
}
else
{
int IndexV = To_Fix[i];
IndexC.push_back(std::pair<int, int>(IndexV, IndexV));
WeightC.push_back((ScalarType)PENALTY);
}
}
}
static void CollectBarycentricConstraints(MeshType &mesh,
const Parameter &SParam,
std::vector<std::pair<int, int>> &IndexC,
std::vector<ScalarType> &WeightC,
std::vector<int> &IndexRhs,
std::vector<ScalarType> &ValueRhs)
{
ScalarType penalty;
int baseIndex = mesh.vert.size();
for (size_t i = 0; i < SParam.ConstrainedF.size(); i++)
{
//get the index of the current constraint
int IndexConstraint = baseIndex + i;
//add one hard constraint
int FaceN = SParam.ConstrainedF[i].numF;
assert(FaceN >= 0);
assert(FaceN < (int)mesh.face.size());
assert(mesh.face[FaceN].VN() == (int)SParam.ConstrainedF[i].BarycentricW.size());
penalty = ScalarType(1) - SParam.lapWeight;
assert(penalty > ScalarType(0) && penalty < ScalarType(1));
//then add all the weights to impose the constraint
for (int j = 0; j < mesh.face[FaceN].VN(); j++)
{
//get the current weight
ScalarType currW = SParam.ConstrainedF[i].BarycentricW[j];
//get the index of the current vertex
int FaceVert = vcg::tri::Index(mesh, mesh.face[FaceN].V(j));
//then add the constraints componentwise
for (int k = 0; k < 3; k++)
{
//multiply times 3 per component
int IndexV = (FaceVert * 3) + k;
//get the index of the current constraint
int ComponentConstraint = (IndexConstraint * 3) + k;
IndexC.push_back(std::pair<int, int>(ComponentConstraint, IndexV));
WeightC.push_back(currW * penalty);
IndexC.push_back(std::pair<int, int>(IndexV, ComponentConstraint));
WeightC.push_back(currW * penalty);
//this to avoid the 1 on diagonal last entry of mass matrix
IndexC.push_back(std::pair<int, int>(ComponentConstraint, ComponentConstraint));
WeightC.push_back(-1);
}
}
for (int j = 0; j < 3; j++)
{
//get the index of the current constraint
int ComponentConstraint = (IndexConstraint * 3) + j;
//get per component value
ScalarType ComponentV = SParam.ConstrainedF[i].TargetPos.V(j);
//add the diagonal value
IndexRhs.push_back(ComponentConstraint);
ValueRhs.push_back(ComponentV * penalty);
}
}
}
static void MassMatrixEntry(MeshType &m,
std::vector<std::pair<int, int>> &index,
std::vector<ScalarType> &entry,
bool vertexCoord = true)
{
tri::RequireCompactness(m);
typename MeshType::template PerVertexAttributeHandle<ScalarType> h =
tri::Allocator<MeshType>::template GetPerVertexAttribute<ScalarType>(m, "volume");
for (int i = 0; i < m.vn; ++i)
h[i] = 0;
ForEachTetra(m, [&](TetraType &t) {
ScalarType v = Tetra::ComputeVolume(t);
for (int i = 0; i < 4; ++i)
h[tri::Index(m, t.V(i))] += v;
});
ScalarType maxV = 0;
for (int i = 0; i < m.vn; ++i)
maxV = max(maxV, h[i]);
for (int i = 0; i < m.vn; ++i)
{
int currI = i;
index.push_back(std::pair<int, int>(currI, currI));
entry.push_back(h[i] / maxV);
}
tri::Allocator<MeshType>::template DeletePerVertexAttribute<ScalarType>(m, h);
}
static ScalarType ComputeCotangentWeight(TetraType &t, const int i)
{
//i is the edge in the tetra
tetra::Pos<TetraType> pp(&t, Tetra::FofE(i, 0), i, Tetra::VofE(i, 0));
tetra::Pos<TetraType> pt(&t, Tetra::FofE(i, 0), i, Tetra::VofE(i, 0));
ScalarType weight = 0;
do
{
CoordType po0 = t.V(Tetra::VofE(5 - pt.E(), 0))->cP();
CoordType po1 = t.V(Tetra::VofE(5 - pt.E(), 1))->cP();
ScalarType length = vcg::Distance(po0, po1);
ScalarType cot = std::tan((M_PI / 2.) - Tetra::DihedralAngle(*pt.T(), 5 - pt.E()));
weight = (length / 6.) * cot;
pt.FlipT();
pt.FlipF();
} while (pp != pt);
return weight;
}
static void GetLaplacianEntry(MeshType &mesh,
TetraType &t,
std::vector<std::pair<int, int>> &index,
std::vector<ScalarType> &entry,
bool cotangent,
ScalarType weight = 1,
bool vertexCoord = true)
{
// if (cotangent)
// vcg::tri::MeshAssert<MeshType>::OnlyT(mesh);
//iterate on edges
for (int i = 0; i < 6; ++i)
{
weight = 1;//ComputeCotangentWeight(t, i);
int indexV0 = Index(mesh, t.V(Tetra::VofE(i, 0)));
int indexV1 = Index(mesh, t.V(Tetra::VofE(i, 1)));
for (int j = 0; j < 3; j++)
{
//multiply by 3 and add the component
int currI0 = (indexV0 * 3) + j;
int currI1 = (indexV1 * 3) + j;
index.push_back(std::pair<int, int>(currI0, currI0));
entry.push_back(weight);
index.push_back(std::pair<int, int>(currI0, currI1));
entry.push_back(-weight);
index.push_back(std::pair<int, int>(currI1, currI1));
entry.push_back(weight);
index.push_back(std::pair<int, int>(currI1, currI0));
entry.push_back(-weight);
}
}
}
static void GetLaplacianMatrix(MeshType &mesh,
std::vector<std::pair<int, int>> &index,
std::vector<ScalarType> &entry,
bool cotangent,
ScalarType weight = 1,
bool vertexCoord = true)
{
//store the index and the scalar for the sparse matrix
ForEachTetra(mesh, [&](TetraType &t) {
GetLaplacianEntry(mesh, t, index, entry, cotangent, weight);
});
}
public:
static void Compute(MeshType &mesh, Parameter &SParam)
{
//calculate the size of the system
int matr_size = mesh.vert.size() + SParam.ConstrainedF.size();
//the laplacian and the mass matrix
Eigen::SparseMatrix<ScalarType> L, M, B;
//initialize the mass matrix
std::vector<std::pair<int, int>> IndexM;
std::vector<ScalarType> ValuesM;
//add the entries for mass matrix
if (SParam.useMassMatrix)
MassMatrixEntry(mesh, IndexM, ValuesM, !SParam.SmoothQ);
//then add entries for lagrange mult due to barycentric constraints
for (size_t i = 0; i < SParam.ConstrainedF.size(); i++)
{
int baseIndex = (mesh.vert.size() + i) * 3;
if (SParam.SmoothQ)
baseIndex = (mesh.vert.size() + i);
if (SParam.SmoothQ)
{
IndexM.push_back(std::pair<int, int>(baseIndex, baseIndex));
ValuesM.push_back(1);
}
else
{
for (int j = 0; j < 3; j++)
{
IndexM.push_back(std::pair<int, int>(baseIndex + j, baseIndex + j));
ValuesM.push_back(1);
}
}
}
//add the hard constraints
CollectHardConstraints(mesh, SParam, IndexM, ValuesM, SParam.SmoothQ);
//initialize sparse mass matrix
if (!SParam.SmoothQ)
InitSparse(IndexM, ValuesM, matr_size * 3, matr_size * 3, M);
else
InitSparse(IndexM, ValuesM, matr_size, matr_size, M);
//initialize the barycentric matrix
std::vector<std::pair<int, int>> IndexB;
std::vector<ScalarType> ValuesB;
std::vector<int> IndexRhs;
std::vector<ScalarType> ValuesRhs;
//then also collect hard constraints
if (!SParam.SmoothQ)
{
CollectBarycentricConstraints(mesh, SParam, IndexB, ValuesB, IndexRhs, ValuesRhs);
//initialize sparse constraint matrix
InitSparse(IndexB, ValuesB, matr_size * 3, matr_size * 3, B);
}
else
InitSparse(IndexB, ValuesB, matr_size, matr_size, B);
//get the entries for laplacian matrix
std::vector<std::pair<int, int>> IndexL;
std::vector<ScalarType> ValuesL;
GetLaplacianMatrix(mesh, IndexL, ValuesL, SParam.useCotWeight, SParam.lapWeight, !SParam.SmoothQ);
//initialize sparse laplacian matrix
if (!SParam.SmoothQ)
InitSparse(IndexL, ValuesL, matr_size * 3, matr_size * 3, L);
else
InitSparse(IndexL, ValuesL, matr_size, matr_size, L);
for (int i = 0; i < (SParam.degree - 1); i++)
L = L * L;
//then solve the system
Eigen::SparseMatrix<ScalarType> S = (M + B + SParam.lambda * L);
//SimplicialLDLT
Eigen::SimplicialCholesky<Eigen::SparseMatrix<ScalarType>> solver(S);
assert(solver.info() == Eigen::Success);
MatrixXm V;
if (!SParam.SmoothQ)
V = MatrixXm(matr_size * 3, 1);
else
V = MatrixXm(matr_size, 1);
//set the first part of the matrix with vertex values
if (!SParam.SmoothQ)
{
for (size_t i = 0; i < mesh.vert.size(); i++)
{
int index = i * 3;
V(index, 0) = mesh.vert[i].P().X();
V(index + 1, 0) = mesh.vert[i].P().Y();
V(index + 2, 0) = mesh.vert[i].P().Z();
}
}
else
{
for (size_t i = 0; i < mesh.vert.size(); i++)
{
int index = i;
V(index, 0) = mesh.vert[i].Q();
}
}
//then set the second part by considering RHS gien by barycentric constraint
for (size_t i = 0; i < IndexRhs.size(); i++)
{
int index = IndexRhs[i];
ScalarType val = ValuesRhs[i];
V(index, 0) = val;
}
//solve the system
V = solver.solve(M * V).eval();
//then copy back values
if (!SParam.SmoothQ)
{
for (size_t i = 0; i < mesh.vert.size(); i++)
{
int index = i * 3;
mesh.vert[i].P().X() = V(index, 0);
mesh.vert[i].P().Y() = V(index + 1, 0);
mesh.vert[i].P().Z() = V(index + 2, 0);
}
}
else
{
for (size_t i = 0; i < mesh.vert.size(); i++)
{
int index = i;
mesh.vert[i].Q() = V(index, 0);
}
}
}
};
} //end namespace vcg
#endif

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@ -194,6 +194,26 @@ public:
} }
} }
static void VertexBorderFromTT(MeshType &m)
{
RequirePerVertexFlags(m);
RequireTTAdjacency(m);
VertexClearB(m);
for(TetraIterator ti=m.tetra.begin(); ti!=m.tetra.end(); ++ti)
if(!(*ti).IsD())
for(int j = 0; j < 4; ++j)
{
if (tetrahedron::IsBorder(*ti,j))
{
for (int i = 0; i < 3; ++i)
ti->V(Tetra::VofF(j, i))->SetB();
}
}
}
static void FaceBorderFromVF(MeshType &m) static void FaceBorderFromVF(MeshType &m)
{ {
RequirePerFaceFlags(m); RequirePerFaceFlags(m);
@ -380,7 +400,7 @@ public:
/// Compute the PerVertex Border flag deriving it from the face-face adjacency /// Compute the PerVertex Border flag deriving it from the face-face adjacency
static void VertexBorderFromFaceAdj(MeshType &m) static void VertexBorderFromFaceAdj(MeshType &m)
{ {
RequirePerFaceFlags(m); RequirePerFaceFlags(m);
RequirePerVertexFlags(m); RequirePerVertexFlags(m);
RequireFFAdjacency(m); RequireFFAdjacency(m);

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@ -165,7 +165,7 @@ public:
return _e; return _e;
} }
/// Return the index of face as seen from the tetrahedron /// Return the index of edge as seen from the tetrahedron
inline const char & E() const inline const char & E() const
{ {
return _e; return _e;
@ -269,7 +269,7 @@ public:
//get the current vertex //get the current vertex
VertexType *vcurr=T()->V(V()); VertexType *vcurr=T()->V(V());
//get new tetrahedron according to faceto face topology //get new tetrahedron according to tetra to tetra topology
TetraType *nt=T()->TTp(F()); TetraType *nt=T()->TTp(F());
char nfa=T()->TTi(F()); char nfa=T()->TTi(F());
if (nfa!=-1) if (nfa!=-1)