gsHalfEdgeMesh< T >::Boundary Class Reference

Detailed Description

template<class T>
class gismo::gsHalfEdgeMesh< T >::Boundary

Class that maintains boundary of triangle mesh.

A Boundary class object is given by one or more chains of the boundary halfedges. The halfedges are ordered counter clockwise.

An object of the class can be constructed by a vector of all unordered halfedges of the mesh.

There are methods to get the number of halfedges, number of vertices, length, halfedge lengths, first and last halfedge, vertex indices, and distances between two vertices.

Public Member Functions
	Boundary ()
	Empty Constructor.
	Boundary (const std::vector< Halfedge > &halfedges)
	Constructor. More...
T	getDistanceBetween (const size_t &i, const size_t &j) const
	Get distance between vertices. More...
const std::vector< T >	getHalfedgeLengths () const
	Get halfedge lengths. More...
T	getLength () const
	Get length. More...
size_t	getNumberOfVertices () const
	Get number of vertices. More...
T	getShortestDistanceBetween (const size_t &i, const size_t &j, T precision) const
	Get distance between vertices. More...
const std::list< size_t >	getVertexIndices () const
	Get list of vertex indices in the chain. More...
bool	isVertexContained (const size_t &internVertexIndex) const
	Tells if vertex is contained in boundary chain. More...

Private Member Functions
const std::list< Halfedge >	findNonTwinHalfedges (const std::vector< Halfedge > &allHalfedges)
	Finds halfedges without twin halfedge. More...

Private Attributes
std::vector< Chain >	m_boundary
	boundary chains

Constructor & Destructor Documentation

Boundary

(

const std::vector< Halfedge > &

halfedges

)

Constructor.

Boundary is constructed from given halfedges. First all halfedges that do not have a twin halfedge contained in the input vector are found. Then the first halfedge is added to the chain. Step by step the algorithm tries to append a halfedge, non-fitting ones are stored in a queue temporary, until a suitable halfedge is found. All halfedges are put back together and this procedure repeats until the chain is closed AND all halfedges are appended.

Otherwise a error message is printed, input is not suitable.

Parameters

[in]

halfedges

vector of halfedges of the triangle mesh

Member Function Documentation

const std::list< typename gsHalfEdgeMesh< T >::Halfedge > findNonTwinHalfedges ( const std::vector< Halfedge > &  allHalfedges )

private

Finds halfedges without twin halfedge.

This private method takes a vector of unordered halfedges and finds the halfedges that do not have a twin halfedge contained in the same vector.

Parameters

[in]

allHalfedges

const std::vector<Halfedge>& - vector of all halfedges in the mesh

Returns

list of non-twin halfedges (boundary halfedges)

T getDistanceBetween ( const size_t &  i, const size_t &  j  ) const

inline

Get distance between vertices.

The distance between i-th and j-th vertex of the boundary chain is returned. In case i > j the distance between j-th and i-th vertex is returned, provided a closed chain. Otherwise a warning is printed

Parameters

[in]	i	number of the first vertex
[in]	j	number of the second vertex

Returns

(shortest) distance between i-th and j-th vertex

const std::vector<T> getHalfedgeLengths ( ) const

inline

Get halfedge lengths.

This function returns a vector of the ordered halfedge lengths, e. g. vector[i] = length of (i+1)-th halfedge

Returns

vector of halfedges

T getLength ( ) const

inline

Get length.

This function returns the length of the boundary, e.g. the sum of all the halfedge lengths.

Returns

length

size_t getNumberOfVertices ( ) const

inline

Get number of vertices.

This getter function returns the number of vertices of the triangle mesh.

Returns

number of vertices

T getShortestDistanceBetween ( const size_t &  i, const size_t &  j, T  precision  ) const

inline

Get distance between vertices.

The distance between i-th and j-th vertex of the boundary chain is returned. In case the chain is closed, it is checked wheter the distance in a clockwise or counterclockwise direction is shorter, and this one is returned.

Parameters

[in]	i	number of the first vertex
[in]	j	number of the second vertex
[in]	precision	tolerance

Returns

(shortest) distance between vertices

const std::list<size_t > getVertexIndices ( ) const

inline

Get list of vertex indices in the chain.

This method returns a list of all counter-clockwise ordered indices of the boundary.

Returns

list of vertex indices

bool isVertexContained ( const size_t &  internVertexIndex ) const

inline

Tells if vertex is contained in boundary chain.

Parameters

[in]

internVertexIndex

index of the searched point (from m_boundary)

Returns

TRUE if it is contained and FALSE otherwise