vtkSimpleCellTessellator Class Reference

#include <vtkSimpleCellTessellator.h>

Inheritance diagram for vtkSimpleCellTessellator:

[legend]

Collaboration diagram for vtkSimpleCellTessellator:

[legend]

List of all members.

Detailed Description

helper class to perform cell tessellation

vtkSimpleCellTessellator is a helper class to perform adaptive tessellation of particular cell topologies. The major purpose for this class is to transform higher-order cell types (e.g., higher-order finite elements) into linear cells that can then be easily visualized by VTK. This class works in conjunction with the vtkGenericDataSet and vtkGenericAdaptorCell classes.

This algorithm is based on edge subdivision. An error metric along each edge is evaluated, and if the error is greater than some tolerance, the edge is subdivided (as well as all connected 2D and 3D cells). The process repeats until the error metric is satisfied. Since the algorithm is based on edge subdivision it inherently avoid T-junctions.

A significant issue addressed by this algorithm is to insure face compatibility across neigboring cells. That is, diagonals due to face triangulation must match to insure that the mesh is compatible. The algorithm employs a precomputed table to accelerate the tessellation process. The table was generated with the help of vtkOrderedTriangulator the basic idea is that the choice of diagonal is made only by considering the relative value of the point ids.

See also:: vtkGenericCellTessellator vtkGenericSubdivisionErrorMetric vtkAttributesErrorMetric vtkGeometricErrorMetric vtkViewDependentErrorMetric

Tests:: vtkSimpleCellTessellator (Tests)

Definition at line 69 of file vtkSimpleCellTessellator.h.


Public Types
typedef vtkGenericCellTessellator	Superclass
Public Member Functions
virtual const char *	GetClassName ()
virtual int	IsA (const char *type)
void	PrintSelf (ostream &os, vtkIndent indent)
void	Reset ()
void	Initialize (vtkGenericDataSet *ds)
int	GetFixedSubdivisions ()
int	GetMaxSubdivisionLevel ()
int	GetMaxAdaptiveSubdivisions ()
void	SetFixedSubdivisions (int level)
void	SetMaxSubdivisionLevel (int level)

virtual vtkGenericAdaptorCell *	GetGenericCell ()

void	TessellateFace (vtkGenericAdaptorCell cell, vtkGenericAttributeCollection att, vtkIdType index, vtkDoubleArray points, vtkCellArray cellArray, vtkPointData *internalPd)

void	Tessellate (vtkGenericAdaptorCell cell, vtkGenericAttributeCollection att, vtkDoubleArray points, vtkCellArray cellArray, vtkPointData *internalPd)

void	Triangulate (vtkGenericAdaptorCell cell, vtkGenericAttributeCollection att, vtkDoubleArray points, vtkCellArray cellArray, vtkPointData *internalPd)

void	SetSubdivisionLevels (int fixed, int maxLevel)
Static Public Member Functions
static vtkSimpleCellTessellator *	New ()
static int	IsTypeOf (const char *type)
static vtkSimpleCellTessellator *	SafeDownCast (vtkObject *o)
Protected Member Functions
	vtkSimpleCellTessellator ()
	~vtkSimpleCellTessellator ()
void	CopyPoint (vtkIdType pointId)
void	InsertEdgesIntoEdgeTable (vtkTriangleTile &tri)
void	RemoveEdgesFromEdgeTable (vtkTriangleTile &tri)
void	InsertPointsIntoEdgeTable (vtkTriangleTile &tri)
void	InsertEdgesIntoEdgeTable (vtkTetraTile &tetra)
void	RemoveEdgesFromEdgeTable (vtkTetraTile &tetra)
void	AllocateScalars (int size)
int	FindEdgeReferenceCount (double p1[3], double p2[3], vtkIdType &e1, vtkIdType &e2)
int	GetNumberOfCellsUsingFace (int faceId)
int	GetNumberOfCellsUsingEdge (int edgeId)
int	IsEdgeOnFace (double p1[3], double p2[3])
int	FindEdgeParent2D (double p1[3], double p2[3], int &localId)
int	FindEdgeParent (double p1[3], double p2[3], int &localId)
void	AllocatePointIds (int size)

void	InitTetraTile (vtkTetraTile &root, vtkIdType localIds, vtkIdType ids, int edgeIds, int faceIds)

void	TriangulateTriangle (vtkGenericAdaptorCell cell, vtkIdType localIds, vtkIdType ids, int edgeIds, vtkGenericAttributeCollection att, vtkDoubleArray points, vtkCellArray cellArray, vtkPointData internalPd)

int	FacesAreEqual (int *originalFace, int face[3])
Protected Attributes
vtkGenericEdgeTable *	EdgeTable
vtkGenericAdaptorCell *	GenericCell
double *	Scalars
int	ScalarsCapacity
int	PointOffset
vtkGenericCellIterator *	CellIterator
vtkGenericAttributeCollection *	AttributeCollection
vtkGenericDataSet *	DataSet
vtkIdType	NumberOfPoints
int	FixedSubdivisions
int	MaxSubdivisionLevel
int	CurrentSubdivisionLevel
vtkOrderedTriangulator *	Triangulator
vtkCellArray *	Connectivity
vtkPolygon *	Polygon
vtkIdList *	TriangleIds
vtkIdType *	PointIds
int	PointIdsCapacity

vtkDoubleArray *	TessellatePoints
vtkCellArray *	TessellateCellArray
vtkPointData *	TessellatePointData

int *	EdgeIds
int *	FaceIds
Friends
class	vtkTetraTile
class	vtkTriangleTile

Member Typedef Documentation

typedef vtkGenericCellTessellator vtkSimpleCellTessellator::Superclass

Reimplemented from vtkGenericCellTessellator.

Definition at line 73 of file vtkSimpleCellTessellator.h.

Constructor & Destructor Documentation

vtkSimpleCellTessellator::vtkSimpleCellTessellator ( ) [protected]

vtkSimpleCellTessellator::~vtkSimpleCellTessellator ( ) [protected]

Member Function Documentation

static vtkSimpleCellTessellator* vtkSimpleCellTessellator::New ( ) [static]

Create an object with Debug turned off, modified time initialized to zero, and reference counting on.

Reimplemented from vtkObject.

virtual const char* vtkSimpleCellTessellator::GetClassName ( ) [virtual]

Reimplemented from vtkGenericCellTessellator.

static int vtkSimpleCellTessellator::IsTypeOf ( const char * name ) [static]

Return 1 if this class type is the same type of (or a subclass of) the named class. Returns 0 otherwise. This method works in combination with vtkTypeRevisionMacro found in vtkSetGet.h.

Reimplemented from vtkGenericCellTessellator.

virtual int vtkSimpleCellTessellator::IsA ( const char * name ) [virtual]

Return 1 if this class is the same type of (or a subclass of) the named class. Returns 0 otherwise. This method works in combination with vtkTypeRevisionMacro found in vtkSetGet.h.

Reimplemented from vtkGenericCellTessellator.

static vtkSimpleCellTessellator* vtkSimpleCellTessellator::SafeDownCast ( vtkObject * o ) [static]

Reimplemented from vtkGenericCellTessellator.

void vtkSimpleCellTessellator::PrintSelf	(	ostream &	os,
		vtkIndent	indent
	)			`[virtual]`

Methods invoked by print to print information about the object including superclasses. Typically not called by the user (use Print() instead) but used in the hierarchical print process to combine the output of several classes.

Reimplemented from vtkGenericCellTessellator.

virtual vtkGenericAdaptorCell* vtkSimpleCellTessellator::GetGenericCell ( ) [virtual]

Get the higher order cell in order to access the evaluation function.

void vtkSimpleCellTessellator::TessellateFace	(	vtkGenericAdaptorCell *	cell,
		vtkGenericAttributeCollection *	att,
		vtkIdType	index,
		vtkDoubleArray *	points,
		vtkCellArray *	cellArray,
		vtkPointData *	internalPd
	)			`[virtual]`

Tessellate a face of a 3D `cell'. The face is specified by the index value. The result is a set of smaller linear triangles in `cellArray' with `points' and point data `internalPd'.

Precondition:

cell_exists: cell!=0

valid_dimension: cell->GetDimension()==3

valid_index_range: (index>=0) && (index<cell->GetNumberOfBoundaries(2))

att_exists: att!=0

points_exists: points!=0

cellArray_exists: cellArray!=0

internalPd_exists: internalPd!=0

Implements vtkGenericCellTessellator.

void vtkSimpleCellTessellator::Tessellate	(	vtkGenericAdaptorCell *	cell,
		vtkGenericAttributeCollection *	att,
		vtkDoubleArray *	points,
		vtkCellArray *	cellArray,
		vtkPointData *	internalPd
	)			`[virtual]`

Tessellate a 3D `cell'. The result is a set of smaller linear tetrahedra in `cellArray' with `points' and point data `internalPd'.

Precondition:

cell_exists: cell!=0

valid_dimension: cell->GetDimension()==3

att_exists: att!=0

points_exists: points!=0

cellArray_exists: cellArray!=0

internalPd_exists: internalPd!=0

Implements vtkGenericCellTessellator.

void vtkSimpleCellTessellator::Triangulate	(	vtkGenericAdaptorCell *	cell,
		vtkGenericAttributeCollection *	att,
		vtkDoubleArray *	points,
		vtkCellArray *	cellArray,
		vtkPointData *	internalPd
	)			`[virtual]`

Triangulate a 2D `cell'. The result is a set of smaller linear triangles in `cellArray' with `points' and point data `internalPd'.

Precondition:

cell_exists: cell!=0

valid_dimension: cell->GetDimension()==2

att_exists: att!=0

points_exists: points!=0

cellArray_exists: cellArray!=0

internalPd_exists: internalPd!=0

Implements vtkGenericCellTessellator.

void vtkSimpleCellTessellator::Reset ( )

Reset the output for repeated use of this class.

void vtkSimpleCellTessellator::Initialize ( vtkGenericDataSet * ds ) [virtual]

Initialize the tessellator with a data set `ds'.

Implements vtkGenericCellTessellator.

int vtkSimpleCellTessellator::GetFixedSubdivisions ( )

Return the number of fixed subdivisions. It is used to prevent from infinite loop in degenerated cases. For order 3 or higher, if the inflection point is exactly on the mid-point, error metric will not detect that a subdivision is required. 0 means no fixed subdivision: there will be only adaptive subdivisions. The algorithm first performs `GetFixedSubdivisions' non adaptive subdivisions followed by at most `GetMaxAdaptiveSubdivisions' adaptive subdivisions. Hence, there are at most `GetMaxSubdivisionLevel' subdivisions.

Postcondition:: positive_result: result>=0 && result<=GetMaxSubdivisionLevel()

int vtkSimpleCellTessellator::GetMaxSubdivisionLevel ( )

Return the maximum level of subdivision. It is used to prevent from infinite loop in degenerated cases. For order 3 or higher, if the inflection point is exactly on the mid-point, error metric will not detect that a subdivision is required. 0 means no subdivision, neither fixed nor adaptive.

Postcondition:: positive_result: result>=GetFixedSubdivisions()

int vtkSimpleCellTessellator::GetMaxAdaptiveSubdivisions ( )

Return the maximum number of adaptive subdivisions.

Postcondition:: valid_result: result==GetMaxSubdivisionLevel()-GetFixedSubdivisions()

void vtkSimpleCellTessellator::SetFixedSubdivisions ( int level )

Set the number of fixed subdivisions. See GetFixedSubdivisions() for more explanations.

Precondition:: positive_level: level>=0 && level<=GetMaxSubdivisionLevel()

Postcondition:: is_set: GetFixedSubdivisions()==level

void vtkSimpleCellTessellator::SetMaxSubdivisionLevel ( int level )

Set the maximum level of subdivision. See GetMaxSubdivisionLevel() for more explanations.

Precondition:: positive_level: level>=GetFixedSubdivisions()

Postcondition:: is_set: level==GetMaxSubdivisionLevel()

void vtkSimpleCellTessellator::SetSubdivisionLevels	(	int	fixed,
		int	maxLevel
	)

Set both the number of fixed subdivisions and the maximum level of subdivisions. See GetFixedSubdivisions(), GetMaxSubdivisionLevel() and GetMaxAdaptiveSubdivisions() for more explanations.

Precondition:: positive_fixed: fixed>=0
valid_range: fixed<=maxLevel

Postcondition:: fixed_is_set: fixed==GetFixedSubdivisions()
maxLevel_is_set: maxLevel==GetMaxSubdivisionLevel()

void vtkSimpleCellTessellator::CopyPoint ( vtkIdType pointId ) [protected]

Extract point `pointId' from the edge table to the output point and output point data.

void vtkSimpleCellTessellator::InsertEdgesIntoEdgeTable ( vtkTriangleTile & tri ) [protected]

void vtkSimpleCellTessellator::RemoveEdgesFromEdgeTable ( vtkTriangleTile & tri ) [protected]

void vtkSimpleCellTessellator::InsertPointsIntoEdgeTable ( vtkTriangleTile & tri ) [protected]

void vtkSimpleCellTessellator::InsertEdgesIntoEdgeTable ( vtkTetraTile & tetra ) [protected]

void vtkSimpleCellTessellator::RemoveEdgesFromEdgeTable ( vtkTetraTile & tetra ) [protected]

void vtkSimpleCellTessellator::InitTetraTile	(	vtkTetraTile &	root,
		vtkIdType *	localIds,
		vtkIdType *	ids,
		int *	edgeIds,
		int *	faceIds
	)			`[protected]`

Initialize `root' with the sub-tetra defined by the `localIds' points on the complex cell, `ids' are the global ids over the mesh of those points. The sub-tetra is also defined by the ids of its edges and of its faces relative to the complex cell. -1 means that the edge or the face of the sub-tetra is not an original edge or face of the complex cell.

Precondition:

cell_exists: this->GenericCell!=0

localIds_exists: localIds!=0

localIds_size: sizeof(localIds)==4

ids_exists: ids!=0

ids_size: sizeof(ids)==4

edgeIds_exists: edgeIds!=0

edgeIds_size: sizeof(edgeIds)==6

faceIds_exists: faceIds!=0

faceIds_size: sizeof(faceIds)==4

void vtkSimpleCellTessellator::TriangulateTriangle	(	vtkGenericAdaptorCell *	cell,
		vtkIdType *	localIds,
		vtkIdType *	ids,
		int *	edgeIds,
		vtkGenericAttributeCollection *	att,
		vtkDoubleArray *	points,
		vtkCellArray *	cellArray,
		vtkPointData *	internalPd
	)			`[protected]`

Triangulate a triangle of `cell'. This triangle can be the top-level triangle if the cell is a triangle or a toplevel sub-triangle is the cell is a polygon, or a triangular face of a 3D cell or a top-level sub-triangle of a face of a 3D cell if the face is not a triangle. Arguments `localIds', `ids' and `edgeIds' have the same meaning than for InitTetraTile.

Precondition:

cell_exists: cell!=0

localIds_exists: localIds!=0

localIds_size: sizeof(localIds)==3

ids_exists: ids!=0

ids_size: sizeof(ids)==3

edgeIds_exists: edgeIds!=0

edgeIds_size: sizeof(edgeIds)==3

void vtkSimpleCellTessellator::AllocateScalars ( int size ) [protected]

Allocate some memory if Scalars does not exists or is smaller than size.

Precondition:: positive_size: size>0

int vtkSimpleCellTessellator::FindEdgeReferenceCount	(	double	p1[3],
		double	p2[3],
		vtkIdType &	e1,
		vtkIdType &	e2
	)			`[protected]`

int vtkSimpleCellTessellator::GetNumberOfCellsUsingFace ( int faceId ) [protected]

int vtkSimpleCellTessellator::GetNumberOfCellsUsingEdge ( int edgeId ) [protected]

int vtkSimpleCellTessellator::IsEdgeOnFace	(	double	p1[3],
		double	p2[3]
	)			`[protected]`

Is the edge defined by vertices (`p1',`p2') in parametric coordinates on some edge of the original tetrahedron? If yes return on which edge it is, else return -1.

Precondition:: p1!=p2
p1 and p2 are in bounding box (0,0,0) (1,1,1)

Postcondition:: valid_result: (result==-1) || ( result>=0 && result<=5 )

int vtkSimpleCellTessellator::FindEdgeParent2D	(	double	p1[3],
		double	p2[3],
		int &	localId
	)			`[protected]`

Return 1 if the parent of edge defined by vertices (`p1',`p2') in parametric coordinates, is an edge; 3 if there is no parent (the edge is inside). If the parent is an edge, return its id in `localId'.

Precondition:: p1!=p2
p1 and p2 are in bounding box (0,0,0) (1,1,1)

Postcondition:: valid_result: (result==1)||(result==3)

int vtkSimpleCellTessellator::FindEdgeParent	(	double	p1[3],
		double	p2[3],
		int &	localId
	)			`[protected]`

Return 1 if the parent of edge defined by vertices (`p1',`p2') in parametric coordinates, is an edge; 2 if the parent is a face, 3 if there is no parent (the edge is inside). If the parent is an edge or a face, return its id in `localId'.

Precondition:: p1!=p2
p1 and p2 are in bounding box (0,0,0) (1,1,1)

Postcondition:: valid_result: result>=1 && result<=3

void vtkSimpleCellTessellator::AllocatePointIds ( int size ) [protected]

Allocate some memory if PointIds does not exist or is smaller than size.

Precondition:: positive_size: size>0

int vtkSimpleCellTessellator::FacesAreEqual	(	int *	originalFace,
		int	face[3]
	)			`[protected]`

Are the faces `originalFace' and `face' equal? The result is independent from any order or orientation.

Precondition:: originalFace_exists: originalFace!=0

Friends And Related Function Documentation

friend class vtkTetraTile [friend]

Definition at line 356 of file vtkSimpleCellTessellator.h.

friend class vtkTriangleTile [friend]

Definition at line 357 of file vtkSimpleCellTessellator.h.

Member Data Documentation

vtkGenericEdgeTable* vtkSimpleCellTessellator::EdgeTable [protected]

HashTable instead of vtkPointLocator

Definition at line 188 of file vtkSimpleCellTessellator.h.

vtkGenericAdaptorCell* vtkSimpleCellTessellator::GenericCell [protected]

To access the higher order cell from third party library

Definition at line 236 of file vtkSimpleCellTessellator.h.

double* vtkSimpleCellTessellator::Scalars [protected]

Scalar buffer used to save the interpolate values of the attributes The capacity is at least the number of components of the attribute collection ot the current cell.

Definition at line 252 of file vtkSimpleCellTessellator.h.

int vtkSimpleCellTessellator::ScalarsCapacity [protected]

Definition at line 253 of file vtkSimpleCellTessellator.h.

int vtkSimpleCellTessellator::PointOffset [protected]

Number of double value to skip to go to the next point into Scalars array It is 6+attributeCollection->GetNumberOfComponents()

Definition at line 257 of file vtkSimpleCellTessellator.h.

vtkGenericCellIterator* vtkSimpleCellTessellator::CellIterator [protected]

Used to iterate over edges boundaries in GetNumberOfCellsUsingEdges()

Definition at line 260 of file vtkSimpleCellTessellator.h.

vtkGenericAttributeCollection* vtkSimpleCellTessellator::AttributeCollection [protected]

To access the higher order field from third party library

Definition at line 263 of file vtkSimpleCellTessellator.h.