The result of a NurbsCurveEvaluator. More...

#include "nurbsCurveResult.h"

Inheritance diagram for NurbsCurveResult:

Classes
class	AdaptiveSample
Public Member Functions
	NurbsCurveResult (const NurbsBasisVector &basis, const LVecBase4 vecs[], const NurbsVertex *verts, int num_vertices)
	The constructor automatically builds up the result as the product of the indicated set of basis matrices and the indicated table of control vertex positions.
void	adaptive_sample (PN_stdfloat tolerance)
	Determines the set of subdivisions necessary to approximate the curve with a set of linear segments, no point of which is farther than tolerance units from the actual curve.
PN_stdfloat	eval_extended_point (PN_stdfloat t, int d)
	Evaluates the curve in n-dimensional space according to the extended vertices associated with the curve in the indicated dimension.
bool	eval_extended_points (PN_stdfloat t, int d, PN_stdfloat result[], int num_values)
	Simultaneously performs eval_extended_point on a contiguous sequence of dimensions.
bool	eval_point (PN_stdfloat t, LVecBase3 &point)
	Computes the point on the curve corresponding to the indicated value in parametric time.
PN_stdfloat	eval_segment_extended_point (int segment, PN_stdfloat t, int d) const
	Evaluates the curve in n-dimensional space according to the extended vertices associated with the curve in the indicated dimension.
void	eval_segment_extended_points (int segment, PN_stdfloat t, int d, PN_stdfloat result[], int num_values) const
	Simultaneously performs eval_extended_point on a contiguous sequence of dimensions.
void	eval_segment_point (int segment, PN_stdfloat t, LVecBase3 &point) const
	Evaluates the point on the curve corresponding to the indicated value in parametric time within the indicated curve segment.
void	eval_segment_tangent (int segment, PN_stdfloat t, LVecBase3 &tangent) const
	As eval_segment_point, but computes the tangent to the curve at the indicated point.
bool	eval_tangent (PN_stdfloat t, LVecBase3 &tangent)
	Computes the tangent to the curve at the indicated point in parametric time.
PN_stdfloat	get_end_t () const
	Returns the last legal value of t on the curve.
int	get_num_samples () const
	Returns the number of sample points generated by the previous call to adaptive_sample().
int	get_num_segments () const
	Returns the number of piecewise continuous segments within the curve.
const LPoint3 &	get_sample_point (int n) const
	Returns the point on the curve of the nth sample point generated by the previous call to adaptive_sample().
PN_stdfloat	get_sample_t (int n) const
	Returns the t value of the nth sample point generated by the previous call to adaptive_sample().
PN_stdfloat	get_segment_t (int segment, PN_stdfloat t) const
	Accepts a t value in the range [0, 1], and assumed to be relative to the indicated segment (as in eval_segment_point()), and returns the corresponding t value in the entire curve (as in eval_point()).
PN_stdfloat	get_start_t () const
	Returns the first legal value of t on the curve.
	MAKE_SEQ (get_sample_ts, get_num_samples, get_sample_t)
	MAKE_SEQ (get_sample_points, get_num_samples, get_sample_points)

Detailed Description

The result of a NurbsCurveEvaluator.

This object represents a curve in a particular coordinate space. It can return the point and/or tangent to the curve at any point.

This is not related to NurbsCurve, CubicCurveseg or any of the ParametricCurve-derived objects in this module. It is a completely parallel implementation of NURBS curves, and will probably eventually replace the whole ParametricCurve class hierarchy.

Definition at line 38 of file nurbsCurveResult.h.

Constructor & Destructor Documentation

NurbsCurveResult::NurbsCurveResult	(	const NurbsBasisVector &	basis,
		const LVecBase4	vecs[],
		const NurbsVertex *	verts,
		int	num_vertices
	)

The constructor automatically builds up the result as the product of the indicated set of basis matrices and the indicated table of control vertex positions.

Definition at line 27 of file nurbsCurveResult.cxx.

References NurbsBasisVector::get_basis(), NurbsBasisVector::get_num_segments(), NurbsBasisVector::get_order(), NurbsBasisVector::get_vertex_index(), LMatrix4f::set_row(), and LVecBase4f::zero().

Member Function Documentation

void NurbsCurveResult::adaptive_sample ( PN_stdfloat tolerance )

Determines the set of subdivisions necessary to approximate the curve with a set of linear segments, no point of which is farther than tolerance units from the actual curve.

After this call, you may walk through the resulting set of samples with get_num_samples(), get_sample_t(), and get_sample_point().

Definition at line 211 of file nurbsCurveResult.cxx.

References LVecBase3f::almost_equal(), eval_segment_point(), NurbsBasisVector::get_from(), and NurbsBasisVector::get_num_segments().

PN_stdfloat NurbsCurveResult::eval_extended_point	(	PN_stdfloat	t,
		int	d
	)		`[inline]`

Evaluates the curve in n-dimensional space according to the extended vertices associated with the curve in the indicated dimension.

Definition at line 91 of file nurbsCurveResult.I.

References eval_segment_extended_point(), and NurbsBasisVector::scale_t().

bool NurbsCurveResult::eval_extended_points	(	PN_stdfloat	t,
		int	d,
		PN_stdfloat	result[],
		int	num_values
	)		`[inline]`

Simultaneously performs eval_extended_point on a contiguous sequence of dimensions.

The dimensions evaluated are d through (d + num_values - 1); the results are filled into the num_values elements in the indicated result array.

Definition at line 110 of file nurbsCurveResult.I.

References eval_segment_extended_points(), and NurbsBasisVector::scale_t().

bool NurbsCurveResult::eval_point	(	PN_stdfloat	t,
		LVecBase3 &	point
	)		`[inline]`

Computes the point on the curve corresponding to the indicated value in parametric time.

Returns true if the t value is valid, false otherwise.

Definition at line 54 of file nurbsCurveResult.I.

References eval_segment_point(), and NurbsBasisVector::scale_t().

PN_stdfloat NurbsCurveResult::eval_segment_extended_point	(	int	segment,
		PN_stdfloat	t,
		int	d
	)		const

Evaluates the curve in n-dimensional space according to the extended vertices associated with the curve in the indicated dimension.

Definition at line 118 of file nurbsCurveResult.cxx.

References NurbsBasisVector::get_basis(), NurbsVertex::get_extended_vertex(), NurbsBasisVector::get_num_segments(), NurbsBasisVector::get_order(), LMatrix4f::get_row(), and NurbsBasisVector::get_vertex_index().

Referenced by eval_extended_point().

void NurbsCurveResult::eval_segment_extended_points	(	int	segment,
		PN_stdfloat	t,
		int	d,
		PN_stdfloat	result[],
		int	num_values
	)		const

Simultaneously performs eval_extended_point on a contiguous sequence of dimensions.

The dimensions evaluated are d through (d + num_values - 1); the results are filled into the num_values elements in the indicated result array.

Definition at line 162 of file nurbsCurveResult.cxx.

References NurbsBasisVector::get_basis(), NurbsVertex::get_extended_vertex(), NurbsBasisVector::get_num_segments(), NurbsBasisVector::get_order(), LMatrix4f::get_row(), and NurbsBasisVector::get_vertex_index().

Referenced by eval_extended_points().

void NurbsCurveResult::eval_segment_point	(	int	segment,
		PN_stdfloat	t,
		LVecBase3 &	point
	)		const

Evaluates the point on the curve corresponding to the indicated value in parametric time within the indicated curve segment.

t should be in the range [0, 1].

The curve is internally represented as a number of connected (or possibly unconnected) piecewise continuous segments. The exact number of segments for a particular curve depends on the knot vector, and is returned by get_num_segments(). Normally, eval_point() is used to evaluate a point along the continuous curve, but when you care more about local continuity, you can use eval_segment_point() to evaluate the points along each segment.

Definition at line 81 of file nurbsCurveResult.cxx.

Referenced by adaptive_sample(), and eval_point().

void NurbsCurveResult::eval_segment_tangent	(	int	segment,
		PN_stdfloat	t,
		LVecBase3 &	tangent
	)		const

As eval_segment_point, but computes the tangent to the curve at the indicated point.

The tangent vector will not necessarily be normalized, and could be zero, particularly at the endpoints.

Definition at line 101 of file nurbsCurveResult.cxx.

Referenced by eval_tangent().

bool NurbsCurveResult::eval_tangent	(	PN_stdfloat	t,
		LVecBase3 &	tangent
	)		`[inline]`

Computes the tangent to the curve at the indicated point in parametric time.

This tangent vector will not necessarily be normalized, and could be zero. See also eval_point().

Definition at line 73 of file nurbsCurveResult.I.

References eval_segment_tangent(), and NurbsBasisVector::scale_t().

PN_stdfloat NurbsCurveResult::get_end_t ( ) const [inline]

Returns the last legal value of t on the curve.

Definition at line 42 of file nurbsCurveResult.I.

References NurbsBasisVector::get_end_t().

int NurbsCurveResult::get_num_samples ( ) const [inline]

Returns the number of sample points generated by the previous call to adaptive_sample().

Definition at line 154 of file nurbsCurveResult.I.

int NurbsCurveResult::get_num_segments ( ) const [inline]

Returns the number of piecewise continuous segments within the curve.

This number is usually not important unless you plan to call eval_segment_point().

Definition at line 130 of file nurbsCurveResult.I.

References NurbsBasisVector::get_num_segments().

const LPoint3 & NurbsCurveResult::get_sample_point ( int n ) const [inline]

Returns the point on the curve of the nth sample point generated by the previous call to adaptive_sample().

For tangents, or extended points, you should use get_sample_t() and pass it into eval_tangent() or eval_extended_point().

Definition at line 182 of file nurbsCurveResult.I.

References LPoint3f::zero().

PN_stdfloat NurbsCurveResult::get_sample_t ( int n ) const [inline]

Returns the t value of the nth sample point generated by the previous call to adaptive_sample().

Definition at line 165 of file nurbsCurveResult.I.

PN_stdfloat NurbsCurveResult::get_segment_t	(	int	segment,
		PN_stdfloat	t
	)		const `[inline]`

Accepts a t value in the range [0, 1], and assumed to be relative to the indicated segment (as in eval_segment_point()), and returns the corresponding t value in the entire curve (as in eval_point()).

Definition at line 143 of file nurbsCurveResult.I.

References NurbsBasisVector::get_from(), and NurbsBasisVector::get_to().

PN_stdfloat NurbsCurveResult::get_start_t ( ) const [inline]

Returns the first legal value of t on the curve.

Usually this is 0.0.

Definition at line 32 of file nurbsCurveResult.I.

References NurbsBasisVector::get_start_t().

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

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

Classes

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation