CGAL 6.2 - Planar Parameterization of Triangulated Surface Meshes

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CGAL::Surface_mesh_parameterization::Iterative_authalic_parameterizer_3< TriangleMesh_, BorderParameterizer_, SolverTraits_ > Class Template Reference
Reference Manual » Surface Parameterization Methods

`#include <CGAL/Surface_mesh_parameterization/Iterative_authalic_parameterizer_3.h>`

## Definition

template<class TriangleMesh_, class BorderParameterizer_ = Default, class SolverTraits_ = Default>
class CGAL::Surface_mesh_parameterization::Iterative_authalic_parameterizer_3< TriangleMesh_, BorderParameterizer_, SolverTraits_ >

The class `Iterative_authalic_parameterizer_3` implements the Iterative Parameterization algorithm, as described by Jain et al.

[6].

This parameterization is a fixed border parameterization and is part of the authalic parameterization family, meaning that it aims to minimize area distortion between the input surface mesh and the parameterized output. More precisely, the approach used by this parameterizer is to iteratively redistribute the \( L_2\) stretch - as defined by Sander et al. [11] - over the mesh.

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_> CGAL::Surface_mesh_parameterization::Circular_border_arc_length_parameterizer_3 This class parameterizes the border of a 3D surface onto a circle, with an arc-length parameterizatio... Definition: Circular_border_parameterizer_3.h:244
  SolverTraits_ | must be a model of `SparseLinearAlgebraTraits_d`. Note that the system is not symmetric because border vertices are not removed 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: CGAL::Eigen_solver_traits< Eigen::BiCGSTAB<Eigen_sparse_matrix<double>::EigenType, Eigen::IncompleteLUT< double > > > CGAL::Eigen_solver_traits

See also
  `CGAL::Surface_mesh_parameterization::Discrete_authalic_parameterizer_3<TriangleMesh, BorderParameterizer, SolverTraits>`
  `CGAL::Surface_mesh_parameterization::ARAP_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.

## Public Member Functions
| Iterative_authalic_parameterizer_3 (Border_parameterizer border_parameterizer=Border_parameterizer(), Solver_traits sparse_la=Solver_traits())
| Constructor.
template<typename VertexUVmap , typename VertexIndexMap >
void | initialize_system_from_mesh_border (Matrix &A, Vector &Bu, Vector &Bv, const Triangle_mesh &tmesh, halfedge_descriptor bhd, VertexUVmap uvmap, VertexIndexMap vimap) const
| initializes `A`, `Bu`, and `Bv` after border parameterization.
template<typename VertexUVmap , typename VertexIndexMap , typename VertexParameterizedMap >
Error_code | parameterize (Triangle_mesh &tmesh, halfedge_descriptor bhd, VertexUVmap uvmap, VertexIndexMap vimap, VertexParameterizedMap vpmap, const unsigned int &iterations=15)
| computes a one-to-one mapping from a triangular 3D surface mesh to a piece of the 2D space.

## Protected Member Functions
Border_parameterizer & | get_border_parameterizer ()
| Get the object that maps the surface's border onto a 2D space.
Solver_traits & | get_linear_algebra_traits ()
| Get the sparse linear algebra (traits object to access the linear system).

## Constructor & Destructor Documentation

## ◆ Iterative_authalic_parameterizer_3()

template<class TriangleMesh_ , class BorderParameterizer_ = Default, class SolverTraits_ = Default>

CGAL::Surface_mesh_parameterization::Iterative_authalic_parameterizer_3< TriangleMesh_, BorderParameterizer_, SolverTraits_ >::Iterative_authalic_parameterizer_3 | ( | Border_parameterizer | border_parameterizer = `Border_parameterizer()`,
|  | Solver_traits | sparse_la = `Solver_traits()`
| ) |  |

Constructor.

Parameters

  border_parameterizer | Object that maps the surface's border to 2D space
  sparse_la | Traits object to access a sparse linear system

## Member Function Documentation

## ◆ initialize_system_from_mesh_border()

template<class TriangleMesh_ , class BorderParameterizer_ = Default, class SolverTraits_ = Default>
template<typename VertexUVmap , typename VertexIndexMap >

void CGAL::Surface_mesh_parameterization::Iterative_authalic_parameterizer_3< TriangleMesh_, BorderParameterizer_, SolverTraits_ >::initialize_system_from_mesh_border | ( | Matrix & | A,
|  | Vector & | Bu,
|  | Vector & | Bv,
|  | const Triangle_mesh & | tmesh,
|  | halfedge_descriptor | bhd,
|  | VertexUVmap | uvmap,
|  | VertexIndexMap | vimap
| ) |  | const

initializes `A`, `Bu`, and `Bv` after border parameterization.

Fill the border vertices' lines in both linear systems: "u = constant" and "v = constant".

Template Parameters

  VertexUVmap | must be a model of `ReadWritePropertyMap` with `boost::graph_traits<Triangle_mesh>::vertex_descriptor` as key type and Point_2 (type deduced from `Triangle_mesh` using `Kernel_traits`) as value type.
  VertexIndexMap | must be a model of `ReadablePropertyMap` with `boost::graph_traits<Triangle_mesh>::vertex_descriptor` as key type and a unique integer as value type.

Parameters

  A | the matrix in both linear system
  Bu | the right hand side vector in the linear system of x coordinates
  Bv | the right hand side vector in the linear system of y coordinates
  tmesh | a triangulated surface
  bhd | a halfedge descriptor on the boundary of `mesh`
  uvmap | an instantiation of the class `VertexUVmap`
  vimap | an instantiation of the class `VertexIndexMap`

Precondition
  Vertices must be indexed (`vimap` must be initialized).
  `A`, `Bu`, and `Bv` must be allocated.
  Border vertices must be parameterized.

## ◆ parameterize()

template<class TriangleMesh_ , class BorderParameterizer_ = Default, class SolverTraits_ = Default>
template<typename VertexUVmap , typename VertexIndexMap , typename VertexParameterizedMap >

Error_code CGAL::Surface_mesh_parameterization::Iterative_authalic_parameterizer_3< TriangleMesh_, BorderParameterizer_, SolverTraits_ >::parameterize | ( | Triangle_mesh & | tmesh,
|  | halfedge_descriptor | bhd,
|  | VertexUVmap | uvmap,
|  | VertexIndexMap | vimap,
|  | VertexParameterizedMap | vpmap,
|  | const unsigned int & | iterations = `15`
| ) |  |

computes a one-to-one mapping from a triangular 3D surface mesh to a piece of the 2D space.

The mapping is piecewise linear (linear in each triangle). The result is the `(u,v)` pair image of each vertex of the 3D surface.

Template Parameters

  VertexUVmap | must be a model of `ReadWritePropertyMap` with `boost::graph_traits<Triangle_mesh>::vertex_descriptor` as key type and Point_2 (type deduced from `Triangle_mesh` using `Kernel_traits`) as value type.
  VertexIndexMap | must be a model of `ReadablePropertyMap` with `boost::graph_traits<Triangle_mesh>::vertex_descriptor` as key type and a unique integer as value type.
  VertexParameterizedMap | must be a model of `ReadWritePropertyMap` with `boost::graph_traits<Triangle_mesh>::vertex_descriptor` as key type and a Boolean as value type.

Parameters

  tmesh | a triangulated surface
  bhd | a halfedge descriptor on the boundary of `mesh`
  uvmap | an instantiation of the class `VertexUVmap`
  vimap | an instantiation of the class `VertexIndexMap`
  vpmap | an instantiation of the class `VertexParameterizedMap`
  iterations | an integer number of iterations to run the parameterization

Precondition
  `tmesh` must be a triangular mesh.
  The mesh border must be mapped onto a convex polygon.
  The vertices must be indexed (`vimap` must be initialized).