how to decide whether a linear approximation to nonlinear geometry or field should be subdivided More...

#include <vtkEdgeSubdivisionCriterion.h>

Inheritance diagram for vtkEdgeSubdivisionCriterion:

Collaboration diagram for vtkEdgeSubdivisionCriterion:

Public Types
typedef vtkObject	Superclass

Public Types inherited from vtkObject
typedef vtkObjectBase	Superclass

Public Member Functions
virtual int	IsA (const char *type)

vtkEdgeSubdivisionCriterion *	NewInstance () const

virtual void	PrintSelf (ostream &os, vtkIndent indent)

virtual bool	EvaluateEdge (const double p0, double p1, const double *p2, int field_start)=0

virtual int	PassField (int sourceId, int sourceSize, vtkStreamingTessellator *t)

virtual void	ResetFieldList ()

virtual bool	DontPassField (int sourceId, vtkStreamingTessellator *t)

const int *	GetFieldIds () const

const int *	GetFieldOffsets () const

int	GetOutputField (int fieldId) const

int	GetNumberOfFields () const

Public Member Functions inherited from vtkObject
vtkObject *	NewInstance () const

virtual void	DebugOn ()

virtual void	DebugOff ()

bool	GetDebug ()

void	SetDebug (bool debugFlag)

virtual void	Modified ()

virtual unsigned long	GetMTime ()

unsigned long	AddObserver (unsigned long event, vtkCommand *, float priority=0.0f)

unsigned long	AddObserver (const char event, vtkCommand , float priority=0.0f)

vtkCommand *	GetCommand (unsigned long tag)

void	RemoveObserver (vtkCommand *)

void	RemoveObservers (unsigned long event, vtkCommand *)

void	RemoveObservers (const char event, vtkCommand )

int	HasObserver (unsigned long event, vtkCommand *)

int	HasObserver (const char event, vtkCommand )

void	RemoveObserver (unsigned long tag)

void	RemoveObservers (unsigned long event)

void	RemoveObservers (const char *event)

void	RemoveAllObservers ()

int	HasObserver (unsigned long event)

int	HasObserver (const char *event)

template<class U , class T >
unsigned long	AddObserver (unsigned long event, U observer, void(T::*callback)(), float priority=0.0f)

template<class U , class T >
unsigned long	AddObserver (unsigned long event, U observer, void(T::callback)(vtkObject , unsigned long, void *), float priority=0.0f)

template<class U , class T >
unsigned long	AddObserver (unsigned long event, U observer, bool(T::callback)(vtkObject , unsigned long, void *), float priority=0.0f)

int	InvokeEvent (unsigned long event, void *callData)

int	InvokeEvent (const char event, void callData)

int	InvokeEvent (unsigned long event)

int	InvokeEvent (const char *event)

Public Member Functions inherited from vtkObjectBase
const char *	GetClassName () const

virtual void	Delete ()

virtual void	FastDelete ()

void	Print (ostream &os)

virtual void	Register (vtkObjectBase *o)

virtual void	UnRegister (vtkObjectBase *o)

void	SetReferenceCount (int)

void	PrintRevisions (ostream &)

virtual void	PrintHeader (ostream &os, vtkIndent indent)

virtual void	PrintTrailer (ostream &os, vtkIndent indent)

int	GetReferenceCount ()

Static Public Member Functions
static int	IsTypeOf (const char *type)

static vtkEdgeSubdivisionCriterion *	SafeDownCast (vtkObjectBase *o)

Static Public Member Functions inherited from vtkObject
static int	IsTypeOf (const char *type)

static vtkObject *	SafeDownCast (vtkObjectBase *o)

static vtkObject *	New ()

static void	BreakOnError ()

static void	SetGlobalWarningDisplay (int val)

static void	GlobalWarningDisplayOn ()

static void	GlobalWarningDisplayOff ()

static int	GetGlobalWarningDisplay ()

Static Public Member Functions inherited from vtkObjectBase
static int	IsTypeOf (const char *name)

static vtkObjectBase *	New ()

Protected Member Functions
virtual vtkObjectBase *	NewInstanceInternal () const

	vtkEdgeSubdivisionCriterion ()

virtual	~vtkEdgeSubdivisionCriterion ()

bool	ViewDependentEval (const double p0, double p1, double p1_actual, const double p2, int field_start, vtkMatrix4x4 viewtrans, const double pixelSize, double allowableChordErr) const

bool	FixedFieldErrorEval (const double p0, double p1, double p1_actual, const double p2, int field_start, int field_criteria, double *allowableFieldErr) const

Protected Member Functions inherited from vtkObject
	vtkObject ()

virtual	~vtkObject ()

virtual void	RegisterInternal (vtkObjectBase *, int check)

virtual void	UnRegisterInternal (vtkObjectBase *, int check)

void	InternalGrabFocus (vtkCommand mouseEvents, vtkCommand keypressEvents=NULL)

void	InternalReleaseFocus ()

Protected Member Functions inherited from vtkObjectBase
	vtkObjectBase ()

virtual	~vtkObjectBase ()

virtual void	CollectRevisions (ostream &)

virtual void	ReportReferences (vtkGarbageCollector *)

	vtkObjectBase (const vtkObjectBase &)

void	operator= (const vtkObjectBase &)

Protected Attributes
int *	FieldIds

int *	FieldOffsets

int	NumberOfFields

Protected Attributes inherited from vtkObject
bool	Debug

vtkTimeStamp	MTime

vtkSubjectHelper *	SubjectHelper

Protected Attributes inherited from vtkObjectBase
vtkAtomicInt32	ReferenceCount

vtkWeakPointerBase **	WeakPointers

Detailed Description

how to decide whether a linear approximation to nonlinear geometry or field should be subdivided

$Date$ $Revision$

Descendants of this abstract class are used to decide whether a piecewise linear approximation (triangles, lines, ... ) to some nonlinear geometry should be subdivided. This decision may be based on an absolute error metric (chord error) or on some view-dependent metric (chord error compared to device resolution) or on some abstract metric (color error). Or anything else, really. Just so long as you implement the EvaluateEdge member, all will be well.

See also: vtkDataSetSubdivisionAlgorithm vtkStreamingTessellator

Tests:: vtkEdgeSubdivisionCriterion (Tests)

Definition at line 47 of file vtkEdgeSubdivisionCriterion.h.

Member Typedef Documentation

typedef vtkObject vtkEdgeSubdivisionCriterion::Superclass

Definition at line 50 of file vtkEdgeSubdivisionCriterion.h.

Constructor & Destructor Documentation

vtkEdgeSubdivisionCriterion::vtkEdgeSubdivisionCriterion ( )

protected

virtual vtkEdgeSubdivisionCriterion::~vtkEdgeSubdivisionCriterion ( )

protectedvirtual

Member Function Documentation

static int vtkEdgeSubdivisionCriterion::IsTypeOf ( const char * type )

static

virtual int vtkEdgeSubdivisionCriterion::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 vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkObject.

Reimplemented in vtkDataSetEdgeSubdivisionCriterion.

static vtkEdgeSubdivisionCriterion* vtkEdgeSubdivisionCriterion::SafeDownCast ( vtkObjectBase * o )

static

virtual vtkObjectBase* vtkEdgeSubdivisionCriterion::NewInstanceInternal ( ) const

protectedvirtual

Reimplemented from vtkObject.

Reimplemented in vtkDataSetEdgeSubdivisionCriterion.

vtkEdgeSubdivisionCriterion* vtkEdgeSubdivisionCriterion::NewInstance ( ) const

virtual void vtkEdgeSubdivisionCriterion::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 vtkObject.

Reimplemented in vtkDataSetEdgeSubdivisionCriterion.

virtual bool vtkEdgeSubdivisionCriterion::EvaluateEdge	(	const double *	p0,
		double *	p1,
		const double *	p2,
		int	field_start
	)

pure virtual

You must implement this member function in a subclass. It will be called by vtkStreamingTessellator for each edge in each primitive that vtkStreamingTessellator generates.

Implemented in vtkDataSetEdgeSubdivisionCriterion.

virtual int vtkEdgeSubdivisionCriterion::PassField	(	int	sourceId,
		int	sourceSize,
		vtkStreamingTessellator *	t
	)

virtual

This is a helper routine called by PassFields() which you may also call directly; it adds sourceSize to the size of the output vertex field values. The offset of the sourceId field in the output vertex array is returned. -1 is returned if sourceSize would force the output to have more than vtkStreamingTessellator::MaxFieldSize field values per vertex.

virtual void vtkEdgeSubdivisionCriterion::ResetFieldList ( )

virtual

Don't pass any field values in the vertex pointer. This is used to reset the list of fields to pass after a successful run of vtkStreamingTessellator.

virtual bool vtkEdgeSubdivisionCriterion::DontPassField	(	int	sourceId,
		vtkStreamingTessellator *	t
	)

virtual

This does the opposite of PassField(); it removes a field from the output (assuming the field was set to be passed). Returns true if any action was taken, false otherwise.

const int * vtkEdgeSubdivisionCriterion::GetFieldIds ( ) const

inline

Return the map from output field id to input field ids. That is, field i of any output vertex from vtkStreamingTessellator will be associated with GetFieldIds()[i] on the input mesh.

Definition at line 157 of file vtkEdgeSubdivisionCriterion.h.

const int * vtkEdgeSubdivisionCriterion::GetFieldOffsets ( ) const

inline

Return the offset into an output vertex array of all fields. That is, field i of any output vertex, p, from vtkStreamingTessellator will have its first entry at p[GetFieldOffsets()[i] ] .

Definition at line 158 of file vtkEdgeSubdivisionCriterion.h.

int vtkEdgeSubdivisionCriterion::GetOutputField ( int fieldId ) const

Return the output ID of an input field. Returns -1 if fieldId is not set to be passed to the output.

int vtkEdgeSubdivisionCriterion::GetNumberOfFields ( ) const

inline

Return the number of fields being evaluated at each output vertex. This is the length of the arrays returned by GetFieldIds() and GetFieldOffsets().

Definition at line 159 of file vtkEdgeSubdivisionCriterion.h.

bool vtkEdgeSubdivisionCriterion::ViewDependentEval	(	const double *	p0,
		double *	p1,
		double *	p1_actual,
		const double *	p2,
		int	field_start,
		vtkMatrix4x4 *	viewtrans,
		const double *	pixelSize,
		double	allowableChordErr
	)		const

protected

Perform the core logic for a view-dependent subdivision. Returns true if subdivision should occur, false otherwise. This is to be used by subclasses once the mesh-specific evaluation routines have been called to get the actual (as opposed to linearly interpolated) midpoint coordinates. Currently, this handles only geometry, but could conceivably test scalar fields as well.

Parameters

p0	is the first endpoint of the edge
p1	is the linearly interpolated midpoint of the edge
p1_actual	is the actual midpoint of the edge
p2	is the second endpoint of the edge
field_start	is the offset into the above arrays indicating where the scalar field values start (when isosurfacing, the embedding dimension may be smaller than the number of parametric coordinates).
viewtrans	is the viewing transform (from model to screen coordinates). Applying this transform to p0, p1, etc., should yield screen-space coordinates.
pixelSize	is the width and height of a pixel in screen space coordinates.
allowableChordErr	is the maximum allowable distance between p1 and p1_actual, in multiples of pixelSize, before subdivision will occur.

bool vtkEdgeSubdivisionCriterion::FixedFieldErrorEval	(	const double *	p0,
		double *	p1,
		double *	p1_actual,
		const double *	p2,
		int	field_start,
		int	field_criteria,
		double *	allowableFieldErr
	)		const

protected

Perform the core logic for a fixed multi-criterion, scalar-field based subdivision. Returns true if subdivision should occur, false otherwise. This is to be used by subclasses once the mesh-specific evaluation routines have been called to get the actual (as opposed to linearly interpolated) midpoint geometry and field values. Only field values are tested (not geometry) because you can save yourself field evaluations if you check the geometry yourself and it fails the test.

Parameters

p0	is the first endpoint of the edge
p1	is the linearly interpolated midpoint of the edge
p1_actual	is the actual midpoint of the edge
p2	is the second endpoint of the edge
field_start	is the offset into the above arrays indicating where the scalar field values start (when isosurfacing, the embedding dimension may be smaller than the number of parametric coordinates).
field_criteria	is a bitfield specifying which fields (of the fields specified by PassField or PassFields) are to be considered for subdivision. Thus, you may pass fields to the output mesh without using them as subdivision criteria. In than case, the allowableFieldErr will have an empty entry for those fields.
allowableFieldErr	is an array of tolerances, one for each field passed to the output. If the linearly interpolated and actual midpoint values for any field are greater than the value specified here, the member will return true.