Package toxi.geom

Class Spline2D

java.lang.Object

toxi.geom.Spline2D

Direct Known Subclasses:

ParticlePath2D

public class Spline2D
extends Object

This is a generic 3D B-Spline class for curves of arbitrary length, control handles and patches are created and joined automatically as described here: ibiblio.org/e-notes/ Splines/Bint.htm

Thanks to a bug report by Aaron Meyers (http://universaloscillation.com) the toLineStrip2D(int) method has a slightly changed behaviour from version 0014 onwards. In earlier versions erroneous duplicate points would be added near each given control point, which lead to various weird results.

The new behaviour of the curve interpolation/computation is described in the docs for the toLineStrip2D(int) method below.

Version:

0014 Added user adjustable curve tightness control, 0015 Added JAXB annotations and List support for dynamic building of spline

Field Summary

Fields

Modifier and Type	Field	Description
BernsteinPolynomial	bernstein
float[]	bi
Vec2D[]	coeffA
static final int	DEFAULT_RES
static final float	DEFAULT_TIGHTNESS
Vec2D[]	delta
List<Vec2D>	pointList

Constructor Summary

Constructors

Constructor	Description
Spline2D()	Constructs an empty spline container with default curve tightness.
Spline2D(List<Vec2D> rawPoints)
Spline2D(List<Vec2D> rawPoints, BernsteinPolynomial b, float tightness)
Spline2D(Vec2D[] pointArray)
Spline2D(Vec2D[] pointArray, BernsteinPolynomial b, float tightness)

Method Summary

Modifier and Type	Method	Description
Spline2D	add(float x, float y)
Spline2D	add(ReadonlyVec2D p)	Adds a copy of the given point to the list of control points.
final int	getNumPoints()	Returns the number of control points.
List<Vec2D>	getPointList()
float	getTightness()
Spline2D	setPointList(List<Vec2D> plist)	Overrides the current control points with the given list.
Spline2D	setTightness(float tightness)	Sets the tightness for future curve interpolation calls.
LineStrip2D	toLineStrip2D(int res)	Computes all curve vertices based on the resolution/number of subdivisions requested.
void	updateCoefficients()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

DEFAULT_TIGHTNESS

public static final float DEFAULT_TIGHTNESS

See Also:

• Constant Field Values

DEFAULT_RES

public static final int DEFAULT_RES

See Also:

• Constant Field Values

pointList

public List<Vec2D> pointList

bernstein

public BernsteinPolynomial bernstein

delta

public Vec2D[] delta

coeffA

public Vec2D[] coeffA

bi

public float[] bi

Constructor Details

Spline2D

public Spline2D()

Constructs an empty spline container with default curve tightness. You need to populate the spline manually by using add(ReadonlyVec2D) .

Spline2D

public Spline2D(List<Vec2D> rawPoints)

Parameters:

rawPoints - list of control point vectors

Spline2D

public Spline2D(List<Vec2D> rawPoints,
 BernsteinPolynomial b,
 float tightness)

Parameters:

rawPoints - list of control point vectors

b - predefined Bernstein polynomial (good for reusing)

tightness - default curve tightness used for the interpolated vertices setTightness(float)

Spline2D

public Spline2D(Vec2D[] pointArray)

Parameters:

pointArray - array of control point vectors

Spline2D

public Spline2D(Vec2D[] pointArray,
 BernsteinPolynomial b,
 float tightness)

Parameters:

pointArray - array of control point vectors

b - predefined Bernstein polynomial (good for reusing)

tightness - default curve tightness used for the interpolated vertices setTightness(float)

Method Details

add

public Spline2D add(float x,
 float y)

add

public Spline2D add(ReadonlyVec2D p)

Adds a copy of the given point to the list of control points.

Parameters:

p -

Returns:

itself

getNumPoints

public final int getNumPoints()

Returns the number of control points.

Returns:

the numP

getPointList

public List<Vec2D> getPointList()

Returns:

the pointList

getTightness

public float getTightness()

Returns:

the spline3d tightness

Since:

0014 (rev.216)

See Also:

• setTightness(float)

setPointList

public Spline2D setPointList(List<Vec2D> plist)

Overrides the current control points with the given list.

Parameters:

plist - the pointList to set

Returns:

itself

setTightness

public Spline2D setTightness(float tightness)

Sets the tightness for future curve interpolation calls. Default value is 0.25. A value of 0.0 equals linear interpolation between the given curve input points. Curve behaviour for values outside the 0.0 .. 0.5 interval is unspecified and becomes increasingly less intuitive. Negative values are possible too and create interesting results (in some cases).

Parameters:

tightness - the tightness value used for the next call to toLineStrip2D(int)

Since:

0014 (rev. 216)

toLineStrip2D

public LineStrip2D toLineStrip2D(int res)

Computes all curve vertices based on the resolution/number of subdivisions requested. The higher, the more vertices are computed:

(number of control points - 1) * resolution + 1

Since version 0014 the automatic placement of the curve handles can also be manipulated via the setTightness(float) method.

Parameters:

res - the number of vertices to be computed per segment between original control points (incl. control point always at the start of each segment)

Returns:

list of Vec2D vertices along the curve

updateCoefficients

public void updateCoefficients()