Face class for navigating a DCEL mesh. More...

#include <EBGeometry_DCEL_Face.hpp>

Collaboration diagram for EBGeometry::DCEL::FaceT< T, Meta >:

[legend]

Public Types
using	Vec3 = Vec3T< T >
	Alias for vector type.

using	Vertex = VertexT< T, Meta >
	Alias for vertex type.

using	Edge = EdgeT< T, Meta >
	Alias for edge type.

using	Face = FaceT< T, Meta >
	Alias for face type.

using	VertexPtr = std::shared_ptr< Vertex >
	Alias for vertex pointer type.

using	EdgePtr = std::shared_ptr< Edge >
	Alias for edge pointer type.

using	FacePtr = std::shared_ptr< Face >
	Alias for face pointer type.

using	EdgeIterator = EdgeIteratorT< T, Meta >
	Alias for edge iterator.

Public Member Functions
	FaceT ()=default
	Default constructor. Sets the half-edge to zero and the inside/outside algorithm to crossing number algorithm.

	FaceT (const EdgePtr &a_edge)
	Partial constructor. Calls default constructor but associates a half-edge.

	FaceT (const Face &a_otherFace)
	Copy constructor.

	FaceT (Face &&a_otherFace)=default
	Move constructor.

	~FaceT ()=default
	Destructor (does nothing)

Face &	operator= (const Face &a_otherFace) noexcept
	Copy assignment operator.

Face &	operator= (Face &&a_otherFace)=default
	Move assignment operator.

void	define (const Vec3 &a_normal, const EdgePtr &a_edge) noexcept
	Define function which sets the normal vector and half-edge.

void	reconcile ()
	Reconcile face. This will compute the normal vector, area, centroid, and the 2D embedding of the polygon.

void	computePolygon2D ()
	Compute the 2D embedding of this polygon from the current normal vector and topology, without touching the normal vector, centroid, or area.

void	flipNormal () noexcept
	Flip the normal vector.

void	setHalfEdge (const EdgePtr &a_halfEdge) noexcept
	Set the half edge.

void	setMetaData (const Meta &a_metaData) noexcept
	Set the meta-data.

void	setInsideOutsideAlgorithm (typename Polygon2D< T >::InsideOutsideAlgorithm &a_algorithm) noexcept
	Set the inside/outside algorithm when determining if a point projects to the inside or outside of the polygon.

EdgePtr	getHalfEdge () noexcept
	Get the starting half-edge.

EdgePtr	getHalfEdge () const noexcept
	Get the starting half-edge (const overload).

Vec3T< T > &	getCentroid () noexcept
	Get modifiable centroid.

const Vec3T< T > &	getCentroid () const noexcept
	Get immutable centroid.

T &	getCentroid (const size_t a_dir) noexcept
	Get modifiable centroid position in specified coordinate direction.

const T &	getCentroid (const size_t a_dir) const noexcept
	Get immutable centroid position in specified coordinate direction.

Vec3T< T > &	getNormal () noexcept
	Get modifiable normal vector.

const Vec3T< T > &	getNormal () const noexcept
	Get immutable normal vector.

T &	getArea () noexcept
	Get modifiable polygon area (computed during reconcile()).

const T &	getArea () const noexcept
	Get immutable polygon area (computed during reconcile()).

Meta &	getMetaData () noexcept
	Get meta-data.

const Meta &	getMetaData () const noexcept
	Get meta-data (const overload)

T	signedDistance (const Vec3 &a_x0) const noexcept
	Compute the signed distance to a point.

T	unsignedDistance2 (const Vec3 &a_x0) const noexcept
	Compute the unsigned squared distance to a point.

std::vector< Vec3T< T > >	getAllVertexCoordinates () const
	Return the coordinates of all the vertices on this polygon.

std::vector< VertexPtr >	gatherVertices () const
	Return all the vertices on this polygon.

std::vector< EdgePtr >	gatherEdges () const
	Return all the half-edges on this polygon.

Vec3T< T >	getSmallestCoordinate () const
	Get the lower-left-most coordinate of this polygon face.

Vec3T< T >	getHighestCoordinate () const
	Get the upper-right-most coordinate of this polygon face.

Protected Member Functions
void	computeCentroid ()
	Compute the centroid position of this polygon.

void	computeNormal ()
	Compute the normal position of this polygon.

void	computeArea ()
	Compute the area of this polygon and cache it in m_area.

void	normalizeNormalVector () noexcept
	Normalize the normal vector, ensuring it has a length of 1.

Vec3T< T >	projectPointIntoFacePlane (const Vec3 &a_p) const noexcept
	Compute the projection of a point onto the polygon face plane.

bool	isPointInsideFace (const Vec3 &a_p) const noexcept
	Check if a point projects to inside or outside the polygon face.

Protected Attributes
std::weak_ptr< Edge >	m_halfEdge
	This polygon's half-edge. A valid face will always have this set.

Vec3	m_normal = Vec3::zeros()
	Polygon face normal vector.

Vec3	m_centroid = Vec3::zeros()
	Polygon face centroid position.

Meta	m_metaData {}
	Meta-data attached to this face.

T	m_area {T(0)}
	Cached polygon face area (stored by reconcile()).

std::shared_ptr< Polygon2D< T > >	m_poly2 = nullptr
	2D embedding of this polygon. This is the 2D view of the current object projected along its normal vector cardinal.

Polygon2D< T >::InsideOutsideAlgorithm	m_poly2Algorithm = Polygon2D<T>::InsideOutsideAlgorithm::CrossingNumber
	Algorithm for inside/outside tests.

Detailed Description

template<class T, class Meta>
class EBGeometry::DCEL::FaceT< T, Meta >

Face class for navigating a DCEL mesh.

Class which represents a polygon face in a double-edge connected list (DCEL).

Template Parameters

T	Floating-point precision type.
Meta	User-defined metadata type.

This class is a polygon face in a DCEL mesh. It contains pointer storage to one of the half-edges that circulate the inside of the polygon face, as well as having a normal vector, a centroid, and an area. This class supports signed distance computations. These computations require algorithms that compute e.g. the winding number of the polygon, or the number of times a ray cast passes through it. Thus, one of its central features is that it can be embedded in 2D by projecting it along the cardinal direction of its normal vector. To be fully consistent with a DCEL structure the class stores a reference to one of its half edges, but for performance reasons it also stores references to the other half edges.

Note: To compute the distance from a point to the face one must determine if the point projects "inside" or "outside" the polygon. There are several algorithms for this, and by default this class uses a crossing number algorithm.

Template Parameters

T	Floating-point precision type.
Meta	User-defined metadata type.

Constructor & Destructor Documentation

◆ FaceT() [1/3]

template<class T , class Meta >

EBGeometry::DCEL::FaceT< T, Meta >::FaceT ( const EdgePtr & a_edge )

Partial constructor. Calls default constructor but associates a half-edge.

Parameters

[in] a_edge Half-edge

◆ FaceT() [2/3]

template<class T , class Meta >

EBGeometry::DCEL::FaceT< T, Meta >::FaceT ( const Face & a_otherFace )

Copy constructor.

Copies the normal vector, half-edge pointer, centroid, and area from the other face. Meta-data (m_metaData), the 2D embedding (m_poly2), and the inside/outside algorithm (m_poly2Algorithm) are deliberately NOT copied – they default-construct instead; use setMetaData() and reconcile() afterwards if they need to be (re)populated. Rationale: m_halfEdge is a back-reference into a specific mesh's topology (same as VertexT/EdgeT's copy constructors), so copying it wholesale is not topologically meaningful in general, but is occasionally useful. m_normal, m_centroid, and m_area are plain geometric/cached values with no such concern, so they are copied like any other value. operator=(const Face&) has identical semantics.

Parameters

[in] a_otherFace Other face to copy from.

◆ FaceT() [3/3]

template<class T , class Meta >

EBGeometry::DCEL::FaceT< T, Meta >::FaceT ( Face && a_otherFace )

default

Move constructor.

Unlike the copy constructor, this transfers the entire state (including m_metaData, m_poly2, and m_poly2Algorithm) from a_otherFace, since moving relocates a single object's identity. Defaulted (memberwise move) rather than hand-written: explicitly defaulting is required here since the presence of a user-declared copy constructor would otherwise suppress the implicitly-generated move constructor. Not marked noexcept since Meta is an unconstrained template parameter whose move constructor is not guaranteed to be noexcept.

Parameters

[in,out] a_otherFace Other face.

Member Function Documentation

◆ computePolygon2D()

template<class T , class Meta >

void EBGeometry::DCEL::FaceT< T, Meta >::computePolygon2D ( )

inline

Compute the 2D embedding of this polygon from the current normal vector and topology, without touching the normal vector, centroid, or area.

Unlike reconcile(), this does not recompute the normal vector, so it is safe to call after manually restoring a normal vector (e.g. when deep-copying a face and preserving whatever normal it had, including one set via flipNormal()) without having that normal silently overwritten by a geometrically-derived one.

Note: The face must be complete with half edges and there can be no dangling edges.

◆ define()

template<class T , class Meta >

void EBGeometry::DCEL::FaceT< T, Meta >::define	(	const Vec3 &	a_normal,
		const EdgePtr &	a_edge
	)

inlinenoexcept

Define function which sets the normal vector and half-edge.

Parameters

[in]	a_normal	Normal vector
[in]	a_edge	Half edge

◆ gatherEdges()

template<class T , class Meta >

std::vector< EdgePtr > EBGeometry::DCEL::FaceT< T, Meta >::gatherEdges ( ) const

inline

Return all the half-edges on this polygon.

This builds a list of all the edges and returns it.

Returns: Vector of shared pointers to all half-edges on this polygon.

◆ gatherVertices()

template<class T , class Meta >

std::vector< VertexPtr > EBGeometry::DCEL::FaceT< T, Meta >::gatherVertices ( ) const

inline

Return all the vertices on this polygon.

This builds a list of all the vertices and returns it.

Returns: Vector of shared pointers to all vertices on this polygon.

◆ getAllVertexCoordinates()

template<class T , class Meta >

std::vector< Vec3T< T > > EBGeometry::DCEL::FaceT< T, Meta >::getAllVertexCoordinates ( ) const

inline

Return the coordinates of all the vertices on this polygon.

This builds a list of all the vertex coordinates and returns it.

Returns: Vector of 3D coordinates of all vertices on this polygon.

◆ getArea() [1/2]

template<class T , class Meta >

const T & EBGeometry::DCEL::FaceT< T, Meta >::getArea ( ) const

inlinenoexcept

Get immutable polygon area (computed during reconcile()).

Returns: Const reference to m_area.

◆ getArea() [2/2]

template<class T , class Meta >

T & EBGeometry::DCEL::FaceT< T, Meta >::getArea ( )

inlinenoexcept

Get modifiable polygon area (computed during reconcile()).

Returns: Reference to m_area.

◆ getCentroid() [1/4]

template<class T , class Meta >

const Vec3T< T > & EBGeometry::DCEL::FaceT< T, Meta >::getCentroid ( ) const

inlinenoexcept

Get immutable centroid.

Returns: Const reference to the centroid vector.

◆ getCentroid() [2/4]

template<class T , class Meta >

Vec3T< T > & EBGeometry::DCEL::FaceT< T, Meta >::getCentroid ( )

inlinenoexcept

Get modifiable centroid.

Returns: Reference to the centroid vector.

◆ getCentroid() [3/4]

template<class T , class Meta >

const T & EBGeometry::DCEL::FaceT< T, Meta >::getCentroid ( const size_t a_dir ) const

inlinenoexcept

Get immutable centroid position in specified coordinate direction.

Parameters

[in] a_dir Coordinate direction

Returns: Const reference to the a_dir-th coordinate of the centroid.

◆ getCentroid() [4/4]

template<class T , class Meta >

T & EBGeometry::DCEL::FaceT< T, Meta >::getCentroid ( const size_t a_dir )

inlinenoexcept

Get modifiable centroid position in specified coordinate direction.

Parameters

[in] a_dir Coordinate direction

Returns: Reference to the a_dir-th coordinate of the centroid.

◆ getHalfEdge() [1/2]

template<class T , class Meta >

EdgePtr EBGeometry::DCEL::FaceT< T, Meta >::getHalfEdge ( ) const

inlinenoexcept

Get the starting half-edge (const overload).

Returns: Starting half-edge, or nullptr.

◆ getHalfEdge() [2/2]

template<class T , class Meta >

EdgePtr EBGeometry::DCEL::FaceT< T, Meta >::getHalfEdge ( )

inlinenoexcept

Get the starting half-edge.

Returns a shared_ptr obtained by locking the internal weak_ptr (see the class-level note on ownership near m_halfEdge). Returns nullptr if the edge has been destroyed, which should not happen while the owning mesh is alive.

Returns: Starting half-edge, or nullptr.

◆ getHighestCoordinate()

template<class T , class Meta >

Vec3T< T > EBGeometry::DCEL::FaceT< T, Meta >::getHighestCoordinate ( ) const

inline

Get the upper-right-most coordinate of this polygon face.

Returns: Upper-right-most coordinate of this polygon face.

◆ getMetaData() [1/2]

template<class T , class Meta >

const Meta & EBGeometry::DCEL::FaceT< T, Meta >::getMetaData ( ) const

inlinenoexcept

Get meta-data (const overload)

Returns: Const reference to the metadata.

◆ getMetaData() [2/2]

template<class T , class Meta >

Meta & EBGeometry::DCEL::FaceT< T, Meta >::getMetaData ( )

inlinenoexcept

Get meta-data.

Returns: Reference to the metadata.

◆ getNormal() [1/2]

template<class T , class Meta >

const Vec3T< T > & EBGeometry::DCEL::FaceT< T, Meta >::getNormal ( ) const

inlinenoexcept

Get immutable normal vector.

Returns: Const reference to the normal vector.

◆ getNormal() [2/2]

template<class T , class Meta >

Vec3T< T > & EBGeometry::DCEL::FaceT< T, Meta >::getNormal ( )

inlinenoexcept

Get modifiable normal vector.

Returns: Reference to the normal vector.

◆ getSmallestCoordinate()

template<class T , class Meta >

Vec3T< T > EBGeometry::DCEL::FaceT< T, Meta >::getSmallestCoordinate ( ) const

inline

Get the lower-left-most coordinate of this polygon face.

Returns: Lower-left-most coordinate of this polygon face.

◆ isPointInsideFace()

template<class T , class Meta >

bool EBGeometry::DCEL::FaceT< T, Meta >::isPointInsideFace ( const Vec3 & a_p ) const

inlineprotectednoexcept

Check if a point projects to inside or outside the polygon face.

Parameters

[in] a_p Point in space

Returns: Returns true if a_p projects to inside the polygon and false otherwise.

◆ operator=() [1/2]

template<class T , class Meta >

Face & EBGeometry::DCEL::FaceT< T, Meta >::operator= ( const Face & a_otherFace )

noexcept

Copy assignment operator.

Has the same semantics as the copy constructor; see its documentation.

Parameters

[in] a_otherFace Other face.

Returns: Reference to (*this).

◆ operator=() [2/2]

template<class T , class Meta >

Face & EBGeometry::DCEL::FaceT< T, Meta >::operator= ( Face && a_otherFace )

default

Move assignment operator.

Has the same full-state-transfer semantics as the move constructor (defaulted memberwise move; see its documentation for why this must be defaulted explicitly).

Parameters

[in,out] a_otherFace Other face.

Returns: Reference to (*this).

◆ projectPointIntoFacePlane()

template<class T , class Meta >

Vec3T< T > EBGeometry::DCEL::FaceT< T, Meta >::projectPointIntoFacePlane ( const Vec3 & a_p ) const

inlineprotectednoexcept

Compute the projection of a point onto the polygon face plane.

Parameters

[in] a_p Point in space

Returns: Projected point in the face plane.

◆ reconcile()

template<class T , class Meta >

void EBGeometry::DCEL::FaceT< T, Meta >::reconcile ( )

inline

Reconcile face. This will compute the normal vector, area, centroid, and the 2D embedding of the polygon.

Note: "Everything" must be set before doing this, i.e. the face must be complete with half edges and there can be no dangling edges.

◆ setHalfEdge()

template<class T , class Meta >

void EBGeometry::DCEL::FaceT< T, Meta >::setHalfEdge ( const EdgePtr & a_halfEdge )

inlinenoexcept

Set the half edge.

Parameters

[in] a_halfEdge Half edge

◆ setInsideOutsideAlgorithm()

template<class T , class Meta >

void EBGeometry::DCEL::FaceT< T, Meta >::setInsideOutsideAlgorithm ( typename Polygon2D< T >::InsideOutsideAlgorithm & a_algorithm )

inlinenoexcept

Set the inside/outside algorithm when determining if a point projects to the inside or outside of the polygon.

Parameters

[in] a_algorithm Desired algorithm

Note: See CD_DCELAlgorithms.H for options (and CD_DCELPolyImplem.H for how the algorithms operate).

◆ setMetaData()

template<class T , class Meta >

void EBGeometry::DCEL::FaceT< T, Meta >::setMetaData ( const Meta & a_metaData )

inlinenoexcept

Set the meta-data.

Parameters

[in] a_metaData Meta-data.

◆ signedDistance()

template<class T , class Meta >

T EBGeometry::DCEL::FaceT< T, Meta >::signedDistance ( const Vec3 & a_x0 ) const

inlinenoexcept

Compute the signed distance to a point.

Parameters

[in] a_x0 Point in space

This algorithm operates by checking if the input point projects to the inside of the polygon. If it does then the distance is just the projected distance onto the polygon plane and the sign is well-defined. Otherwise, we check the distance to the edges of the polygon.

Returns: Signed distance to the face; sign determined by normal direction.

◆ unsignedDistance2()

template<class T , class Meta >

T EBGeometry::DCEL::FaceT< T, Meta >::unsignedDistance2 ( const Vec3 & a_x0 ) const

inlinenoexcept

Compute the unsigned squared distance to a point.

Parameters

[in] a_x0 Point in space

This algorithm operates by checking if the input point projects to the inside of the polygon. If it does then the distance is just the projected distance onto the polygon plane. Otherwise, we check the distance to the edges of the polygon.

Returns: Squared unsigned distance to the face.

Member Data Documentation

◆ m_halfEdge

template<class T , class Meta >

std::weak_ptr<Edge> EBGeometry::DCEL::FaceT< T, Meta >::m_halfEdge

protected

This polygon's half-edge. A valid face will always have this set.

Stored as a weak_ptr: the edge is owned by the mesh's own edge list, and a plain shared_ptr here would form a reference cycle with EdgeT::m_face (and, transitively, with EdgeT::m_nextEdge/m_pairEdge and VertexT::m_outgoingEdge) that shared_ptr's reference counting can never collect.

◆ m_metaData

template<class T , class Meta >

Meta EBGeometry::DCEL::FaceT< T, Meta >::m_metaData {}

protected

Meta-data attached to this face.

Value-initialized so that every constructor leaves it in a defined state: for a fundamental Meta type (e.g. short, int), a member with no initializer and no explicit mention in a constructor's member-initializer list is left indeterminate, not zero.

The documentation for this class was generated from the following files:

Source/EBGeometry_DCEL.hpp
Source/EBGeometry_DCEL_Face.hpp

Public Types

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ FaceT() [1/3]

◆ FaceT() [2/3]

◆ FaceT() [3/3]

Member Function Documentation

◆ computePolygon2D()

◆ define()

◆ gatherEdges()

◆ gatherVertices()

◆ getAllVertexCoordinates()

◆ getArea() [1/2]

◆ getArea() [2/2]

◆ getCentroid() [1/4]

◆ getCentroid() [2/4]

◆ getCentroid() [3/4]

◆ getCentroid() [4/4]

◆ getHalfEdge() [1/2]

◆ getHalfEdge() [2/2]

◆ getHighestCoordinate()

◆ getMetaData() [1/2]

◆ getMetaData() [2/2]

◆ getNormal() [1/2]

◆ getNormal() [2/2]

◆ getSmallestCoordinate()

◆ isPointInsideFace()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ projectPointIntoFacePlane()

◆ reconcile()

◆ setHalfEdge()

◆ setInsideOutsideAlgorithm()

◆ setMetaData()

◆ signedDistance()

◆ unsignedDistance2()

Member Data Documentation

◆ m_halfEdge

◆ m_metaData