CGAL 5.2 - Planar Parameterization of Triangulated Surface Meshes
CGAL::Surface_mesh_parameterization::Barycentric_mapping_parameterizer_3< TriangleMesh_, BorderParameterizer_, SolverTraits_ > Class Template Reference

#include <CGAL/Surface_mesh_parameterization/Barycentric_mapping_parameterizer_3.h>

Inherits from

CGAL::Surface_mesh_parameterization::Fixed_border_parameterizer_3< TriangleMesh_, Default::Get< BorderParameterizer_, Circular_border_arc_length_parameterizer_3< TriangleMesh_ > >::type, Default::Get< SolverTraits_, SolverTraits_ >::type >.

Definition

template<typename TriangleMesh_, typename BorderParameterizer_ = Default, typename SolverTraits_ = Default>
class CGAL::Surface_mesh_parameterization::Barycentric_mapping_parameterizer_3< TriangleMesh_, BorderParameterizer_, SolverTraits_ >

The class Barycentric_mapping_parameterizer_3 implements Tutte Barycentric Mapping algorithm.

This algorithm is also called Tutte Uniform Weights by other authors [12].

A one-to-one mapping is guaranteed if the surface's border is mapped to a convex polygon.

This class is a strategy called by the main parameterization algorithm Fixed_border_parameterizer_3::parameterize() and it:

  • provides the template parameters BorderParameterizer_ and SolverTraits_.
  • implements compute_w_ij() to compute w_ij, the (i,j)-coefficient of the matrix A for j neighbor vertex of i, based on Tutte Barycentric Mapping method.
Is Model Of:
Parameterizer_3
Template Parameters
TriangleMesh_must be a model of FaceGraph.
BorderParameterizer_is a Strategy to parameterize the surface border and must be a model of Parameterizer_3.
Default:
Circular_border_arc_length_parameterizer_3<TriangleMesh_>
SolverTraits_must be a model of SparseLinearAlgebraTraits_d.
Note that the system is not symmetric because Fixed_border_parameterizer_3 does not remove border vertices from the system.
Default: If Eigen 3.1 (or greater) is available and CGAL_EIGEN3_ENABLED is defined, then an overload of Eigen_solver_traits is provided as default parameter:
Eigen::BiCGSTAB<Eigen_sparse_matrix<double>::EigenType,
Eigen::IncompleteLUT< double > > >
See also
CGAL::Surface_mesh_parameterization::Fixed_border_parameterizer_3<TriangleMesh, BorderParameterizer, SolverTraits>

Public Types

typedef Border_parameterizer_ Border_parameterizer
 Border parameterizer type.
 
typedef SolverTraits_ Solver_traits
 Solver traits type.
 
typedef TriangleMesh_ Triangle_mesh
 Triangle mesh type.
 
typedef boost::graph_traits< Triangle_mesh >::vertex_descriptor vertex_descriptor
 Mesh vertex type.
 
typedef boost::graph_traits< Triangle_mesh >::halfedge_descriptor halfedge_descriptor
 Mesh halfedge type.
 
- Public Types inherited from CGAL::Surface_mesh_parameterization::Fixed_border_parameterizer_3< TriangleMesh_, Default::Get< BorderParameterizer_, Circular_border_arc_length_parameterizer_3< TriangleMesh_ > >::type, Default::Get< SolverTraits_, SolverTraits_ >::type >
typedef Border_parameterizer_ Border_parameterizer
 Border parameterizer type.
 
typedef Default::Get< SolverTraits_, SolverTraits_ >::type Solver_traits
 Solver traits type.
 
typedef TriangleMesh_ Triangle_mesh
 Triangle mesh type.
 
typedef boost::graph_traits< Triangle_mesh >::vertex_descriptor vertex_descriptor
 Mesh vertex type.
 
typedef boost::graph_traits< Triangle_mesh >::halfedge_descriptor halfedge_descriptor
 Mesh halfedge type.
 
typedef Solver_traits::Vector Vector
 Solver vector type.
 
typedef Solver_traits::Matrix Matrix
 Solver matrix type.
 

Public Member Functions

 Barycentric_mapping_parameterizer_3 (Border_parameterizer border_param=Border_parameterizer(), Solver_traits sparse_la=Solver_traits())
 Constructor. More...
 
template<typename VertexUVMap , typename Faces_Container >
bool is_one_to_one_mapping (const Triangle_mesh &mesh, halfedge_descriptor bhd, const VertexUVMap uvmap) const
 returns whether the 3D -> 2D mapping is one-to-one. More...
 
- Public Member Functions inherited from CGAL::Surface_mesh_parameterization::Fixed_border_parameterizer_3< TriangleMesh_, Default::Get< BorderParameterizer_, Circular_border_arc_length_parameterizer_3< TriangleMesh_ > >::type, Default::Get< SolverTraits_, SolverTraits_ >::type >
 Fixed_border_parameterizer_3 (Border_parameterizer border_param=Border_parameterizer(), Solver_traits sparse_la=Solver_traits())
 Constructor. More...
 
virtual ~Fixed_border_parameterizer_3 ()
 Destructor of base class should be virtual.
 
Error_code parameterize (Triangle_mesh &mesh, halfedge_descriptor bhd, VertexUVmap uvmap, VertexIndexMap vimap, VertexParameterizedMap vpmap)
 computes a one-to-one mapping from a triangular 3D surface mesh to a piece of the 2D space. More...
 

Protected Member Functions

virtual NT compute_w_ij (const Triangle_mesh &, vertex_descriptor, Vertex_around_target_circulator< Triangle_mesh >) const
 computes w_ij, the coefficient of matrix A for j neighbor vertex of i. More...
 
- Protected Member Functions inherited from CGAL::Surface_mesh_parameterization::Fixed_border_parameterizer_3< TriangleMesh_, Default::Get< BorderParameterizer_, Circular_border_arc_length_parameterizer_3< TriangleMesh_ > >::type, Default::Get< SolverTraits_, SolverTraits_ >::type >
void initialize_system_from_mesh_border (Matrix &A, Vector &Bu, Vector &Bv, const Triangle_mesh &mesh, halfedge_descriptor bhd, VertexUVmap uvmap, VertexIndexMap vimap) const
 initializes A, Bu and Bv after border parameterization. More...
 
Error_code setup_inner_vertex_relations (Matrix &A, Vector &, Vector &, const Triangle_mesh &mesh, vertex_descriptor vertex, VertexIndexMap vimap) const
 Compute the line i of matrix A for i inner vertex: More...
 
Border_parameterizerget_border_parameterizer ()
 Get the object that maps the surface's border onto a 2D space.
 
Solver_traitsget_linear_algebra_traits ()
 Get the sparse linear algebra (traits object to access the linear system).
 

Constructor & Destructor Documentation

◆ Barycentric_mapping_parameterizer_3()

template<typename TriangleMesh_ , typename BorderParameterizer_ = Default, typename SolverTraits_ = Default>
CGAL::Surface_mesh_parameterization::Barycentric_mapping_parameterizer_3< TriangleMesh_, BorderParameterizer_, SolverTraits_ >::Barycentric_mapping_parameterizer_3 ( Border_parameterizer  border_param = Border_parameterizer(),
Solver_traits  sparse_la = Solver_traits() 
)

Constructor.

Parameters
border_paramObject that maps the surface's border to 2D space.
sparse_laTraits object to access a sparse linear system.

Member Function Documentation

◆ compute_w_ij()

template<typename TriangleMesh_ , typename BorderParameterizer_ = Default, typename SolverTraits_ = Default>
virtual NT CGAL::Surface_mesh_parameterization::Barycentric_mapping_parameterizer_3< TriangleMesh_, BorderParameterizer_, SolverTraits_ >::compute_w_ij ( const Triangle_mesh ,
vertex_descriptor  ,
Vertex_around_target_circulator< Triangle_mesh  
) const
protectedvirtual

computes w_ij, the coefficient of matrix A for j neighbor vertex of i.

In the Tutte Barycentric Mapping algorithm, we have w_ij = 1, for j neighbor vertex of i.

Implements CGAL::Surface_mesh_parameterization::Fixed_border_parameterizer_3< TriangleMesh_, Default::Get< BorderParameterizer_, Circular_border_arc_length_parameterizer_3< TriangleMesh_ > >::type, Default::Get< SolverTraits_, SolverTraits_ >::type >.

◆ is_one_to_one_mapping()

template<typename TriangleMesh_ , typename BorderParameterizer_ = Default, typename SolverTraits_ = Default>
template<typename VertexUVMap , typename Faces_Container >
bool CGAL::Surface_mesh_parameterization::Barycentric_mapping_parameterizer_3< TriangleMesh_, BorderParameterizer_, SolverTraits_ >::is_one_to_one_mapping ( const Triangle_mesh mesh,
halfedge_descriptor  bhd,
const VertexUVMap  uvmap 
) const

returns whether the 3D -> 2D mapping is one-to-one.

Theorem: A one-to-one mapping is guaranteed if all w_ij coefficients are > 0 (for j vertex neighbor of i) and if the surface border is mapped onto a 2D convex polygon. Here, all w_ij coefficients are equal to 1 (for j vertex neighbor of i), thus a valid embedding is guaranteed if the surface border is mapped onto a 2D convex polygon.