Spline Class Reference

Splines. More...

#include <math/gzmath.hh>

Public Member Functions
	Spline ()
	constructor More...
	~Spline ()
	destructor More...
void	AddPoint (const Vector3 &_pt)
	Adds a control point to the end of the spline. More...
void	Clear ()
	Clears all the points in the spline. More...
Vector3	GetPoint (unsigned int _index) const
	Gets the detail of one of the control points of the spline. More...
unsigned int	GetPointCount () const
	Gets the number of control points in the spline. More...
Vector3	GetTangent (unsigned int _index) const
	Get the tangent value for a point. More...
double	GetTension () const
	Get the tension value. More...
Vector3	Interpolate (double _t) const
	Returns an interpolated point based on a parametric value over the whole series. More...
Vector3	Interpolate (unsigned int _fromIndex, double _t) const
	Interpolates a single segment of the spline given a parametric value. More...
void	RecalcTangents ()
	Recalculates the tangents associated with this spline. More...
void	SetAutoCalculate (bool _autoCalc)
	Tells the spline whether it should automatically calculate tangents on demand as points are added. More...
void	SetTension (double _t)
	Set the tension parameter. More...
void	UpdatePoint (unsigned int _index, const Vector3 &_value)
	Updates a single point in the spline. More...

Protected Attributes
bool	autoCalc
	when true, the tangents are recalculated when the control point change More...
Matrix4	coeffs
	Matrix of coefficients. More...
std::vector< Vector3 >	points
	control points More...
std::vector< Vector3 >	tangents
	tangents More...
double	tension
	Tension of 0 = Catmull-Rom spline, otherwise a Cardinal spline. More...

Detailed Description

Splines.

Constructor & Destructor Documentation

Spline

(

)

constructor

~Spline

(

)

destructor

Member Function Documentation

void AddPoint

(

const Vector3 &

_pt

)

Adds a control point to the end of the spline.

Parameters

[in]

_pt

point to add

void Clear

(

)

Clears all the points in the spline.

Vector3 GetPoint

(

unsigned int

_index

)

const

Gets the detail of one of the control points of the spline.

Parameters

[in]

_index

the control point index

Returns

the control point, or [0,0,0] and a message on the error stream

unsigned int GetPointCount

(

)

const

Gets the number of control points in the spline.

Returns

the count

Vector3 GetTangent

(

unsigned int

_index

)

const

Get the tangent value for a point.

Parameters

[in]

_index

the control point index

double GetTension

(

)

const

Get the tension value.

Returns

The value of the tension, which is between 0.0 and 1.0

Vector3 Interpolate

(

double

_t

)

const

Returns an interpolated point based on a parametric value over the whole series.

Parameters

[in]

_t

parameter (range 0 to 1)

Vector3 Interpolate	(	unsigned int	_fromIndex,
		double	_t
	)		const

Interpolates a single segment of the spline given a parametric value.

Parameters

[in]	_fromIndex	The point index to treat as t = 0. fromIndex + 1 is deemed to be t = 1
[in]	_t	Parametric value

void RecalcTangents

(

)

Recalculates the tangents associated with this spline.

Remarks

If you tell the spline not to update on demand by calling setAutoCalculate(false) then you must call this after completing your updates to the spline points.

void SetAutoCalculate

(

bool

_autoCalc

)

Tells the spline whether it should automatically calculate tangents on demand as points are added.

Remarks

The spline calculates tangents at each point automatically based on the input points. Normally it does this every time a point changes. However, if you have a lot of points to add in one go, you probably don't want to incur this overhead and would prefer to defer the calculation until you are finished setting all the points. You can do this by calling this method with a parameter of 'false'. Just remember to manually call the recalcTangents method when you are done.

Parameters

[in]

_autoCalc

If true, tangents are calculated for you whenever a point changes. If false, you must call reclacTangents to recalculate them when it best suits.

void SetTension

(

double

_t

)

Set the tension parameter.

A value of 0 = Catmull-Rom spline.

Parameters

[in]

_t

Tension value between 0.0 and 1.0

void UpdatePoint	(	unsigned int	_index,
		const Vector3 &	_value
	)

Updates a single point in the spline.

Remarks

an error to the error stream is printed when the index is out of bounds

Parameters

[in]	_index	the control point index
[in]	_value	the new position

Member Data Documentation

bool autoCalc

protected

when true, the tangents are recalculated when the control point change

Matrix4 coeffs

protected

Matrix of coefficients.

std::vector<Vector3> points

protected

control points

std::vector<Vector3> tangents

protected

tangents

double tension

protected

Tension of 0 = Catmull-Rom spline, otherwise a Cardinal spline.

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

• Spline.hh