A Nonuniform Rational B-Spline. More...

#include "nurbsCurve.h"

Inheritance diagram for NurbsCurve:

Classes
class	CV
Public Member Functions
	NurbsCurve (const ParametricCurve &pc)
	Constructs a NURBS curve equivalent to the indicated (possibly non-NURBS) curve.
	NurbsCurve (int order, int num_cvs, const float knots[], const LVecBase4f cvs[])
	Constructs a NURBS curve according to the indicated NURBS parameters.
virtual bool	convert_to_nurbs (ParametricCurve *nc) const
	Stores in the indicated NurbsCurve a NURBS representation of an equivalent curve.
virtual TypeHandle	force_init_type ()
CubicCurveseg *	get_curveseg (int ti)
	Returns the curve segment corresponding to the given index.
virtual LVecBase4f	get_cv (int n) const
	Returns the position in homogeneous space of the indicated CV.
virtual float	get_knot (int n) const
	Retrieves the value of the indicated knot.
virtual int	get_num_cvs () const
virtual int	get_num_knots () const
	Returns the number of knots on the curve.
virtual NurbsCurveInterface *	get_nurbs_interface ()
	Returns a pointer to the object as a NurbsCurveInterface object if it happens to be a NURBS-style curve; otherwise, returns NULL.
virtual int	get_order () const
virtual TypeHandle	get_type () const
virtual bool	insert_cv (float t)
	Inserts a new CV into the middle of the curve at the indicated parametric value.
virtual PandaNode *	make_copy () const
	Returns a newly-allocated PandaNode that is a shallow copy of this one.
virtual bool	rebuild_curveseg (int rtype0, float t0, const LVecBase4f &v0, int rtype1, float t1, const LVecBase4f &v1, int rtype2, float t2, const LVecBase4f &v2, int rtype3, float t3, const LVecBase4f &v3)
	Rebuilds the current curve segment (as selected by the most recent call to find_curve()) according to the specified properties (see CubicCurveseg::compute_seg).
virtual bool	recompute ()
	Recalculates the curve basis according to the latest position of the CV's, knots, etc.
virtual void	remove_all_cvs ()
	Removes all CV's from the curve.
virtual bool	remove_cv (int n)
	Removes the indicated CV from the curve.
virtual bool	set_cv (int n, const LVecBase4f &v)
	Repositions the indicated CV.
virtual bool	set_knot (int n, float t)
	Sets the value of the indicated knot.
virtual void	set_order (int order)
	Changes the order of the curve.
virtual bool	stitch (const ParametricCurve a, const ParametricCurve b)
	Regenerates this curve as one long curve: the first curve connected end-to-end with the second one.
virtual void	write (ostream &out, int indent_level=0) const
Static Public Member Functions
static TypeHandle	get_class_type ()
static void	init_type ()
static void	register_with_read_factory ()
	Initializes the factory for reading these things from Bam files.
Protected Member Functions
virtual int	append_cv_impl (const LVecBase4f &v)
	Adds a new CV to the end of the curve.
void	fillin (DatagramIterator &scan, BamReader *manager)
	Function that reads out of the datagram (or asks manager to read) all of the data that is needed to re-create this object and stores it in the appropiate place.
int	find_cv (float t)
	Finds the first knot whose value is >= t, or -1 if t is beyond the end of the curve.
virtual bool	format_egg (ostream &out, const string &name, const string &curve_type, int indent_level) const
	Formats the curve as an egg structure to write to the indicated stream.
virtual void	write_datagram (BamWriter *manager, Datagram &me)
	Function to write the important information in the particular object to a Datagram.
Static Protected Member Functions
static TypedWritable *	make_NurbsCurve (const FactoryParams &params)
	Factory method to generate an object of this type.
Protected Attributes
pvector< CV >	_cvs
int	_order

Detailed Description

A Nonuniform Rational B-Spline.

This class is actually implemented as a PiecewiseCurve made up of several CubicCurvesegs, each of which is created using the nurbs_basis() method. The list of CV's and knots is kept here, within the NurbsCurve class.

This class is the original Panda-native implementation of a NURBS curve. It is typedeffed as "NurbsCurve" and performs all NURBS curve functions if we do not have the NURBS++ library available.

However, if we *do* have the NURBS++ library, another class exists, the NurbsPPCurve, which is a wrapper around that library and provides some additional functionality. In that case, the other class is typedeffed to "NurbsCurve" instead of this one, and performs most of the NURBS curve functions. This class then becomes vestigial.

Definition at line 47 of file nurbsCurve.h.

Constructor & Destructor Documentation

NurbsCurve::NurbsCurve ( const ParametricCurve & pc )

Constructs a NURBS curve equivalent to the indicated (possibly non-NURBS) curve.

Definition at line 44 of file nurbsCurve.cxx.

References ParametricCurve::convert_to_nurbs().

NurbsCurve::NurbsCurve	(	int	order,
		int	num_cvs,
		const float	knots[],
		const LVecBase4f	cvs[]
	)

Constructs a NURBS curve according to the indicated NURBS parameters.

Definition at line 60 of file nurbsCurve.cxx.

References recompute(), and set_knot().

Member Function Documentation

int NurbsCurve::append_cv_impl ( const LVecBase4f & v ) [protected, virtual]

Adds a new CV to the end of the curve.

Creates a new knot value by adding 1 to the last knot value. Returns the index of the new CV.

Implements NurbsCurveInterface.

Definition at line 515 of file nurbsCurve.cxx.

References get_knot().

bool NurbsCurve::convert_to_nurbs ( ParametricCurve * nc ) const [virtual]

Stores in the indicated NurbsCurve a NURBS representation of an equivalent curve.

Returns true if successful, false otherwise.

Reimplemented from NurbsCurveInterface.

Definition at line 492 of file nurbsCurve.cxx.

References ParametricCurve::set_curve_type().

void NurbsCurve::fillin	(	DatagramIterator &	scan,
		BamReader *	manager
	)		`[protected, virtual]`

Function that reads out of the datagram (or asks manager to read) all of the data that is needed to re-create this object and stores it in the appropiate place.

Reimplemented from PiecewiseCurve.

Definition at line 608 of file nurbsCurve.cxx.

References DatagramIterator::get_float64(), DatagramIterator::get_int8(), DatagramIterator::get_uint32(), and LVecBase4f::read_datagram().

Referenced by make_NurbsCurve().

int NurbsCurve::find_cv ( float t ) [protected]

Finds the first knot whose value is >= t, or -1 if t is beyond the end of the curve.

Definition at line 540 of file nurbsCurve.cxx.

Referenced by insert_cv().

bool NurbsCurve::format_egg	(	ostream &	out,
		const string &	name,
		const string &	curve_type,
		int	indent_level
	)		const `[protected, virtual]`

Formats the curve as an egg structure to write to the indicated stream.

Returns true on success, false on failure.

Reimplemented from NurbsCurveInterface.

Definition at line 528 of file nurbsCurve.cxx.

CubicCurveseg * NurbsCurve::get_curveseg ( int ti ) [inline]

Returns the curve segment corresponding to the given index.

Reimplemented from PiecewiseCurve.

Definition at line 22 of file nurbsCurve.I.

LVecBase4f NurbsCurve::get_cv ( int n ) const [virtual]

Returns the position in homogeneous space of the indicated CV.

Implements NurbsCurveInterface.

Definition at line 257 of file nurbsCurve.cxx.

References LVecBase4f::zero().

float NurbsCurve::get_knot ( int n ) const [virtual]

Retrieves the value of the indicated knot.

Implements NurbsCurveInterface.

Definition at line 290 of file nurbsCurve.cxx.

Referenced by append_cv_impl(), insert_cv(), rebuild_curveseg(), and recompute().

int NurbsCurve::get_num_knots ( ) const [virtual]

Returns the number of knots on the curve.

Implements NurbsCurveInterface.

Definition at line 141 of file nurbsCurve.cxx.

Referenced by set_knot().

NurbsCurveInterface * NurbsCurve::get_nurbs_interface ( ) [virtual]

Returns a pointer to the object as a NurbsCurveInterface object if it happens to be a NURBS-style curve; otherwise, returns NULL.

Reimplemented from ParametricCurve.

Definition at line 480 of file nurbsCurve.cxx.

bool NurbsCurve::insert_cv ( float t ) [virtual]

Inserts a new CV into the middle of the curve at the indicated parametric value.

This doesn't change the shape or timing of the curve; however, it is irreversible: if the new CV is immediately removed, the curve will be changed. Returns true if successful, false otherwise.

Implements NurbsCurveInterface.

Definition at line 158 of file nurbsCurve.cxx.

References find_cv(), and get_knot().

PandaNode * NurbsCurve::make_copy ( ) const [virtual]

Returns a newly-allocated PandaNode that is a shallow copy of this one.

It will be a different pointer, but its internal data may or may not be shared with that of the original PandaNode. No children will be copied.

Reimplemented from PandaNode.

Definition at line 97 of file nurbsCurve.cxx.

TypedWritable * NurbsCurve::make_NurbsCurve ( const FactoryParams & params ) [static, protected]

Factory method to generate an object of this type.

Definition at line 568 of file nurbsCurve.cxx.

References fillin().

Referenced by register_with_read_factory().

bool NurbsCurve::rebuild_curveseg	(	int	rtype0,
		float	t0,
		const LVecBase4f &	v0,
		int	rtype1,
		float	t1,
		const LVecBase4f &	v1,
		int	rtype2,
		float	t2,
		const LVecBase4f &	v2,
		int	rtype3,
		float	t3,
		const LVecBase4f &	v3
	)		`[virtual]`

Rebuilds the current curve segment (as selected by the most recent call to find_curve()) according to the specified properties (see CubicCurveseg::compute_seg).

Returns true if possible, false if something goes horribly wrong.

Reimplemented from PiecewiseCurve.

Definition at line 351 of file nurbsCurve.cxx.

References CubicCurveseg::compute_seg(), LMatrix4f::get_col(), get_knot(), LMatrix4f::set_col(), and LVecBase4f::zero().

bool NurbsCurve::recompute ( ) [virtual]

Recalculates the curve basis according to the latest position of the CV's, knots, etc.

Until this function is called, adjusting the NURBS parameters will have no visible effect on the curve. Returns true if the resulting curve is valid, false otherwise.

Reimplemented from ParametricCurve.

Definition at line 312 of file nurbsCurve.cxx.

References get_knot(), and PiecewiseCurve::insert_curveseg().

Referenced by NurbsCurve(), and stitch().

void NurbsCurve::register_with_read_factory ( ) [static]

Initializes the factory for reading these things from Bam files.

Reimplemented from PandaNode.

Definition at line 558 of file nurbsCurve.cxx.

References BamReader::get_factory(), make_NurbsCurve(), and Factory< Type >::register_factory().

void NurbsCurve::remove_all_cvs ( ) [virtual]

Removes all CV's from the curve.

Implements NurbsCurveInterface.

Definition at line 231 of file nurbsCurve.cxx.

bool NurbsCurve::remove_cv ( int n ) [virtual]

Removes the indicated CV from the curve.

Returns true if the CV index was valid, false otherwise.

Implements NurbsCurveInterface.

Definition at line 216 of file nurbsCurve.cxx.

bool NurbsCurve::set_cv	(	int	n,
		const LVecBase4f &	v
	)		`[virtual]`

Repositions the indicated CV.

Returns true if successful, false otherwise.

Implements NurbsCurveInterface.

Definition at line 243 of file nurbsCurve.cxx.

bool NurbsCurve::set_knot	(	int	n,
		float	t
	)		`[virtual]`

Sets the value of the indicated knot.

There are get_num_cvs() + _order knot values, but the first _order - 1 and the last 1 knot values cannot be changed. It is also an error to set a knot value outside the range of its neighbors.

Implements NurbsCurveInterface.

Definition at line 274 of file nurbsCurve.cxx.

References get_num_knots().

Referenced by NurbsCurve().

void NurbsCurve::set_order ( int order ) [virtual]

Changes the order of the curve.

Must be a value from 1 to 4. Can only be done when there are no cv's.

Implements NurbsCurveInterface.

Definition at line 108 of file nurbsCurve.cxx.

bool NurbsCurve::stitch	(	const ParametricCurve *	a,
		const ParametricCurve *	b
	)		`[virtual]`

Regenerates this curve as one long curve: the first curve connected end-to-end with the second one.

Either a or b may be the same as 'this'.

Returns true if successful, false on failure or if the curve type does not support stitching.

Reimplemented from ParametricCurve.

Definition at line 425 of file nurbsCurve.cxx.

References recompute().

void NurbsCurve::write_datagram	(	BamWriter *	manager,
		Datagram &	me
	)		`[protected, virtual]`

Function to write the important information in the particular object to a Datagram.

Reimplemented from PiecewiseCurve.

Definition at line 585 of file nurbsCurve.cxx.

References Datagram::add_float64(), Datagram::add_int8(), Datagram::add_uint32(), and LVecBase4f::write_datagram().

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

panda/src/parametrics/nurbsCurve.h
panda/src/parametrics/nurbsCurve.cxx
panda/src/parametrics/nurbsCurve.I

NurbsCurve Class Reference

Classes

Public Member Functions

Static Public Member Functions

Protected Member Functions

Static Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation