ON_SubDFaceRegion Class Reference

#include <opennurbs_subd.h>

Public Types
enum	ExtraordinarySource : unsigned char { ExtraordinarySource::Unset = 0, ExtraordinarySource::None = 1, ExtraordinarySource::Level0ExtraordinaryVertex = 2, ExtraordinarySource::Level1NgonCenterVertex = 3 }
	When a ON_SubDFaceRegion::Type is Extraordinary or ExtraordinaryAdjacent, the ExtraordinarySource enum indicates if the source of the extraordinary vertex was a level 0 extraordinary vertex or a level 1 extraordinary vertex at the center of a level 0 N-gon face. More...
enum	Type : unsigned char { Type::Unset = 0, Type::Ordinary = 1, Type::Extraordinary = 2, Type::ExtraordinaryAdjacent = 3 }
	ON_SubDFaceRegion::Type has meaning only for regions of a SubD face that result from two or more subdivisions. The Type is used in creating NURBS approximations of SubD near level 0 extraordinary vertices level 1 extraordinary vertices that result from subdividing level 0 faces that have 3 or 5 or more edges (also called N-gon faces). More...

Public Member Functions
	ON_SubDFaceRegion ()=default
	ON_SubDFaceRegion (const ON_SubDFaceRegion &)=default
	~ON_SubDFaceRegion ()=default
unsigned int	CornerIndexFromVertexId (unsigned int vertex_id) const
bool	IsValid (bool bSilentError) const
const ON_SubDFace *	Level0Face () const
	This is an expert user function that can return either Level0PersistentFace() or a transient face. Using this pointer depends on the constext. If you are not managing the entire creation process of the ON_SubDFaceRegion, you should be using Level0PersistentFace(). More...
const ON_SubDFace *	Level0PersistentFace () const
	An ON_SubDFaceRegion is a subdivision quad of a face. When that face is a level 0 face in an ON_SubD, it is called a persistent face. This function returns faces that have been set as persistent level 0 faces. More...
unsigned	Level0PersistentFaceId () const
	An ON_SubDFaceRegion is a subdivision quad of a face. When that face is a level 0 face in an ON_SubD, it is called a persistent face. This function returns faces that have been set as persistent level 0 faces. More...
const ON_SubDVertex *	Level0PersistentVertex () const
	An ON_SubDFaceRegion is a subdivision quad of a face. When that face is a level 0 face on from an ON_SubD, it is a persistent face and the level 1 quad has one corner at a face vertex. This vertex is returned by Level0PersistentVertex(). NOTE WELL: The caller must insure the parent ON_SubD exists before calling Level0PersistentVertex(). More...
unsigned	Level0PersistentVertexId () const
	An ON_SubDFaceRegion is a subdivision quad of a face. When that face is a level 0 face on from an ON_SubD, it is a persistent face and the level 1 quad has one corner at a face vertex. This vertex is returned by Level0PersistentVertex(). NOTE WELL: The caller must insure the parent ON_SubD exists before calling Level0PersistentVertex(). More...
ON_SubDFaceRegion &	operator= (const ON_SubDFaceRegion &)=default
void	Push (unsigned int quadrant_index)
ON_SubDFaceRegion::ExtraordinarySource	RegionExtraordinarySource () const
	RegionExtraordinarySource() applies only when RegionType() is Extraordinary or ExtraordinaryAdjacent and the region is a result of 2 or more subdivisions. More...
unsigned	RegionExtraordinaryValence () const
	When the region is near a leve 0 or leve 1 extraordinary vertex, this function returns the valence of the extraodinary vertex. When RegionExtraordinarySource() = Level0ExtraordinaryVertex, this is the number of faces and edges around the level 0 vertex. When RegionExtraordinarySource() = Level1NgonCenterVertex, this is the number edges around the level 0 ngon which is also the number of edges and faces around the level 1 extraordinary vertex at the center of the ngon. /// More...
ON_SubDFaceRegion::Type	RegionType () const
	RegionType() applys only when the regions is a result of 2 or more subdivisions. More...
const ON_wString	ToString () const
wchar_t *	ToString (wchar_t *s, size_t s_capacity) const

Static Public Member Functions
static int	CompareSourceLevel0IdAndType (const ON_SubDFaceRegion *lhs, const ON_SubDFaceRegion *rhs)
	CompareSourceLevel0IdAndType is used to sort regions from the same subdivision level around level 0 extraordinary vertices and level 1 extraordinary vertices at the center of ngons. This is typically done in the context of calculating NURBS approsimations for subdivision regions that an extraordinary vertex. The compare is done as follows. 1st compare is RegionExtraordinarySource(). Unset < None < Level0ExtraordinaryVertex < Level1NgonCenterVertex. If lhs and rhs have the same value of RegionExtraordinarySource(), the 2nd compare is the component id. If the common source is Level0ExtraordinaryVertex, the vertex ids of Level0PersistentVertex() are compared. Otherwise the face ids of Level0PersistentFace() are compared. If lhs and rhs have the same component id, the 3rd compare is RegionType(). Unset < Ordinary < Extraordinary < ExtraordinaryAdjacent. Typically, this sort is happing in the context where the Extraordinary regions are being replaced with NURBS approximations that are G2 with ExtraordinaryAdjacent regions. More...

Public Attributes
ON_SubDComponentRegion	m_edge_region [4]
ON_SubDComponentRegion	m_face_region
	Identifies a region of an ON_SubDFace. More...
ON_SubDSectorId	m_sector_id [4]
unsigned int	m_vertex_id [4] = {}

Static Public Attributes
static const ON_SubDFaceRegion	Empty

Member Enumeration Documentation

ExtraordinarySource

enum ON_SubDFaceRegion::ExtraordinarySource : unsigned char

strong

When a ON_SubDFaceRegion::Type is Extraordinary or ExtraordinaryAdjacent, the ExtraordinarySource enum indicates if the source of the extraordinary vertex was a level 0 extraordinary vertex or a level 1 extraordinary vertex at the center of a level 0 N-gon face.

Enumerator
Unset
None
Level0ExtraordinaryVertex	The regions are around a level 0 extraordinary vertex. These are smooth vertices that have 3 or 5 or more smooth edges.
Level1NgonCenterVertex	The regions are around a level 1 extraordinary vertex created at the center of a level 0 N-gon face. These level 1 vertices are smooth and have N smooth edges.

Type

enum ON_SubDFaceRegion::Type : unsigned char

strong

ON_SubDFaceRegion::Type has meaning only for regions of a SubD face that result from two or more subdivisions. The Type is used in creating NURBS approximations of SubD near level 0 extraordinary vertices level 1 extraordinary vertices that result from subdividing level 0 faces that have 3 or 5 or more edges (also called N-gon faces).

Enumerator
Unset
Ordinary	Ordinary subdivision regions are bounded by 4 smooth subdivision edges. Ordinary subdivision regions can be represents with a bibezier whose control points conincide whte the subdivided SubD's control points. Orindary regions do not chare a smooth edge with Extraordinary regions.
Extraordinary	Extraordinary subdivision regions are bounded by 4 smooth subdivision edges. Extraordinary subdivision regions have a corner at either a level 0 extraordinary vertex or a level 1 extraordinary vertex created at the center of a level 0 ngon face (3 or 5 or more edges). In general, the SubD limit surface of these regions cannot be exactly represented by an rational polynomial surface. No amount of subdivsion changes this in the general case. Thus, any bibezier or NURBS patch representing these regions is an approximation.
ExtraordinaryAdjacent	ExtraordinaryAdjacent subdivision regions are bounded by 4 smooth subdivision edges. ExtraordinaryAdjacent regions share an edge with Extraordinary regions. Mathematically, Ordindary and ExtraordinaryAdjacent regions have the same subdivion properties. ExtraordinaryAdjacent get a special identifying mark because they are used to specify boundary conditions for calculating NURBS patches that approximate Extraordinary regions. There are 2 ExtraordinaryAdjacent regions for each Extraordinary region. A subdivision levels>= 2, these regions can be exactly represented by a bicubicbezier patch with 16 control points equal to the SubD level 2 control points around the region.

Constructor & Destructor Documentation

ON_SubDFaceRegion() [1/2]

ON_SubDFaceRegion::ON_SubDFaceRegion ( )

default

~ON_SubDFaceRegion()

ON_SubDFaceRegion::~ON_SubDFaceRegion ( )

default

ON_SubDFaceRegion() [2/2]

ON_SubDFaceRegion::ON_SubDFaceRegion ( const ON_SubDFaceRegion &  )

default

Member Function Documentation

CompareSourceLevel0IdAndType()

static int ON_SubDFaceRegion::CompareSourceLevel0IdAndType ( const ON_SubDFaceRegion *  lhs, const ON_SubDFaceRegion *  rhs  )

static

CompareSourceLevel0IdAndType is used to sort regions from the same subdivision level around level 0 extraordinary vertices and level 1 extraordinary vertices at the center of ngons. This is typically done in the context of calculating NURBS approsimations for subdivision regions that an extraordinary vertex. The compare is done as follows. 1st compare is RegionExtraordinarySource(). Unset < None < Level0ExtraordinaryVertex < Level1NgonCenterVertex. If lhs and rhs have the same value of RegionExtraordinarySource(), the 2nd compare is the component id. If the common source is Level0ExtraordinaryVertex, the vertex ids of Level0PersistentVertex() are compared. Otherwise the face ids of Level0PersistentFace() are compared. If lhs and rhs have the same component id, the 3rd compare is RegionType(). Unset < Ordinary < Extraordinary < ExtraordinaryAdjacent. Typically, this sort is happing in the context where the Extraordinary regions are being replaced with NURBS approximations that are G2 with ExtraordinaryAdjacent regions.

Parameters

lhs
rhs

Returns

CornerIndexFromVertexId()

unsigned int ON_SubDFaceRegion::CornerIndexFromVertexId

(

unsigned int

vertex_id

)

const

Returns: If vertex_id > 0 and there is a unique element of m_vertex_id[] with the same value, the index of that element is returned (0,1,2 or 3). Otherwise ON_UNSET_UNINT_INDEX is returned.

IsValid()

bool ON_SubDFaceRegion::IsValid

(

bool

bSilentError

)

const

Level0Face()

const ON_SubDFace* ON_SubDFaceRegion::Level0Face

(

)

const

This is an expert user function that can return either Level0PersistentFace() or a transient face. Using this pointer depends on the constext. If you are not managing the entire creation process of the ON_SubDFaceRegion, you should be using Level0PersistentFace().

Returns

A persistent or transient face that depends on the context of this ON_SubDFaceRegion class.

Level0PersistentFace()

const ON_SubDFace* ON_SubDFaceRegion::Level0PersistentFace

(

)

const

An ON_SubDFaceRegion is a subdivision quad of a face. When that face is a level 0 face in an ON_SubD, it is called a persistent face. This function returns faces that have been set as persistent level 0 faces.

Returns

A pointer to the level 0 persistent face. It is the caller's responsibility to check for a nullptr and to insure the parent ON_SubD exists before dereferencing this pointer.

Level0PersistentFaceId()

unsigned ON_SubDFaceRegion::Level0PersistentFaceId

(

)

const

An ON_SubDFaceRegion is a subdivision quad of a face. When that face is a level 0 face in an ON_SubD, it is called a persistent face. This function returns faces that have been set as persistent level 0 faces.

Returns

The id of the level 0 persistent face or 0 if it is not available.

Level0PersistentVertex()

const ON_SubDVertex* ON_SubDFaceRegion::Level0PersistentVertex

(

)

const

An ON_SubDFaceRegion is a subdivision quad of a face. When that face is a level 0 face on from an ON_SubD, it is a persistent face and the level 1 quad has one corner at a face vertex. This vertex is returned by Level0PersistentVertex(). NOTE WELL: The caller must insure the parent ON_SubD exists before calling Level0PersistentVertex().

Returns

A pointer to the level 0 persistent vertex. It is the caller's responsibility to check for a nullptr and to insure the parent ON_SubD exists before dereferencing this pointer.

Level0PersistentVertexId()

unsigned ON_SubDFaceRegion::Level0PersistentVertexId

(

)

const

An ON_SubDFaceRegion is a subdivision quad of a face. When that face is a level 0 face on from an ON_SubD, it is a persistent face and the level 1 quad has one corner at a face vertex. This vertex is returned by Level0PersistentVertex(). NOTE WELL: The caller must insure the parent ON_SubD exists before calling Level0PersistentVertex().

Returns

The id of the level 0 persistent vertex or 0 if it is not available.

operator=()

ON_SubDFaceRegion& ON_SubDFaceRegion::operator= ( const ON_SubDFaceRegion &  )

default

Push()

void ON_SubDFaceRegion::Push

(

unsigned int

quadrant_index

)

RegionExtraordinarySource()

ON_SubDFaceRegion::ExtraordinarySource ON_SubDFaceRegion::RegionExtraordinarySource

(

)

const

RegionExtraordinarySource() applies only when RegionType() is Extraordinary or ExtraordinaryAdjacent and the region is a result of 2 or more subdivisions.

Returns

RegionExtraordinaryValence()

unsigned ON_SubDFaceRegion::RegionExtraordinaryValence

(

)

const

When the region is near a leve 0 or leve 1 extraordinary vertex, this function returns the valence of the extraodinary vertex. When RegionExtraordinarySource() = Level0ExtraordinaryVertex, this is the number of faces and edges around the level 0 vertex. When RegionExtraordinarySource() = Level1NgonCenterVertex, this is the number edges around the level 0 ngon which is also the number of edges and faces around the level 1 extraordinary vertex at the center of the ngon. ///

Returns

If RegionExtraordinarySource() is Level0ExtraordinaryVertex or Level1NgonCenterVertex, the valance of the extraordinary vertex is returned. Otherwise 0 is returned.

RegionType()

ON_SubDFaceRegion::Type ON_SubDFaceRegion::RegionType

(

)

const

RegionType() applys only when the regions is a result of 2 or more subdivisions.

Returns

ToString() [1/2]

const ON_wString ON_SubDFaceRegion::ToString

(

)

const

ToString() [2/2]

wchar_t* ON_SubDFaceRegion::ToString	(	wchar_t *	s,
		size_t	s_capacity
	)		const

Member Data Documentation

Empty

const ON_SubDFaceRegion ON_SubDFaceRegion::Empty

static

m_edge_region

ON_SubDComponentRegion ON_SubDFaceRegion::m_edge_region[4]

When the face region is a quad, m_edge_region[4] identifies regions of ON_SubDEdge elements. When the face region is a sub-quad, these edges may be null or have null ON_SubDEdge pointers and the ids will be zero or ON_SubDComponentRegion::IsTransientId() will be true. When ON_SubDComponentRegion::IsTransientId() is true, the id does not identify a persistent edge in the ON_SubD.

m_face_region

ON_SubDComponentRegion ON_SubDFaceRegion::m_face_region

Identifies a region of an ON_SubDFace.

m_sector_id

ON_SubDSectorId ON_SubDFaceRegion::m_sector_id[4]

mutable

When a vertex is exceptional, a NURBS conversion is typically an approximation of the SubD around the exceptional vertex. There are a variety of post processes that can be applied in this case and the processes need to be applied sector by sector. Note well that when a level zero face is an N-gon with N != 4, the face subdivision point is an exceptional smooth vertex with valence = N. In this case the corresponding m_vertex_id[] value will be zero.

m_vertex_id

unsigned int ON_SubDFaceRegion::m_vertex_id[4] = {}

mutable

If set, these are the vertice ids at the region's limit surface corners. m_vertex_id[] is mutable because these values appear during recursive calculations. When the face region is a sub-quad, these ids will be zero or ON_SubDComponentRegion::IsTransientId() will be true. When ON_SubDComponentRegion::IsTransientId() is true, the id does not identify a persistent vertex in the ON_SubD.