com.badlogic.gdx.math

Class BSpline<T extends Vector<T>>

java.lang.Object

com.badlogic.gdx.math.BSpline<T>

All Implemented Interfaces:

Path<T>

public class BSpline<T extends Vector<T>>
extends Object
implements Path<T>

Author:

Xoppa

Field Summary

Fields

Modifier and Type	Field and Description
boolean	continuous
T[]	controlPoints
int	degree
Array<T>	knots
int	spanCount

Constructor Summary

Constructors

Constructor and Description
BSpline()
BSpline(T[] controlPoints, int degree, boolean continuous)

Method Summary

Modifier and Type	Method and Description
float	approximate(T v)
float	approximate(T in, int near)
float	approximate(T in, int start, int count)
float	approxLength(int samples)
static <T extends Vector<T>> T	calculate(T out, float t, T[] points, int degree, boolean continuous, T tmp) Calculates the n-degree b-spline value for the given position (t).
static <T extends Vector<T>> T	calculate(T out, int i, float u, T[] points, int degree, boolean continuous, T tmp) Calculates the n-degree b-spline value for the given span (i) at the given position (u).
static <T extends Vector<T>> T	cubic_derivative(T out, float t, T[] points, boolean continuous, T tmp) Calculates the cubic b-spline derivative for the given position (t).
static <T extends Vector<T>> T	cubic_derivative(T out, int i, float u, T[] points, boolean continuous, T tmp) Calculates the cubic b-spline derivative for the given span (i) at the given position (u).
static <T extends Vector<T>> T	cubic(T out, float t, T[] points, boolean continuous, T tmp) Calculates the cubic b-spline value for the given position (t).
static <T extends Vector<T>> T	cubic(T out, int i, float u, T[] points, boolean continuous, T tmp) Calculates the cubic b-spline value for the given span (i) at the given position (u).
static <T extends Vector<T>> T	derivative(T out, float t, T[] points, int degree, boolean continuous, T tmp) Calculates the n-degree b-spline derivative for the given position (t).
static <T extends Vector<T>> T	derivative(T out, int i, float u, T[] points, int degree, boolean continuous, T tmp) Calculates the n-degree b-spline derivative for the given span (i) at the given position (u).
T	derivativeAt(T out, float t)
T	derivativeAt(T out, int span, float u)
float	locate(T v)
int	nearest(T in)
int	nearest(T in, int start, int count)
BSpline	set(T[] controlPoints, int degree, boolean continuous)
T	valueAt(T out, float t)
T	valueAt(T out, int span, float u)

Methods inherited from class java.lang.Object

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

Field Detail

controlPoints

public T extends Vector<T>[] controlPoints

knots

public Array<T extends Vector<T>> knots

degree

public int degree

continuous

public boolean continuous

spanCount

public int spanCount

Constructor Detail

BSpline

public BSpline()

BSpline

public BSpline(T[] controlPoints,
               int degree,
               boolean continuous)

Method Detail

cubic

public static <T extends Vector<T>> T cubic(T out,
                                            float t,
                                            T[] points,
                                            boolean continuous,
                                            T tmp)

Calculates the cubic b-spline value for the given position (t).

Parameters:

out - The Vector to set to the result.

t - The position (0<=t<=1) on the spline

points - The control points

continuous - If true the b-spline restarts at 0 when reaching 1

tmp - A temporary vector used for the calculation

Returns:

The value of out

cubic_derivative

public static <T extends Vector<T>> T cubic_derivative(T out,
                                                       float t,
                                                       T[] points,
                                                       boolean continuous,
                                                       T tmp)

Calculates the cubic b-spline derivative for the given position (t).

Parameters:

out - The Vector to set to the result.

t - The position (0<=t<=1) on the spline

points - The control points

continuous - If true the b-spline restarts at 0 when reaching 1

tmp - A temporary vector used for the calculation

Returns:

The value of out

cubic

public static <T extends Vector<T>> T cubic(T out,
                                            int i,
                                            float u,
                                            T[] points,
                                            boolean continuous,
                                            T tmp)

Calculates the cubic b-spline value for the given span (i) at the given position (u).

Parameters:

out - The Vector to set to the result.

i - The span (0<=i

u - The position (0<=u<=1) on the span

points - The control points

continuous - If true the b-spline restarts at 0 when reaching 1

tmp - A temporary vector used for the calculation

Returns:

The value of out

cubic_derivative

public static <T extends Vector<T>> T cubic_derivative(T out,
                                                       int i,
                                                       float u,
                                                       T[] points,
                                                       boolean continuous,
                                                       T tmp)

Calculates the cubic b-spline derivative for the given span (i) at the given position (u).

Parameters:

out - The Vector to set to the result.

i - The span (0<=i

u - The position (0<=u<=1) on the span

points - The control points

continuous - If true the b-spline restarts at 0 when reaching 1

tmp - A temporary vector used for the calculation

Returns:

The value of out

calculate

public static <T extends Vector<T>> T calculate(T out,
                                                float t,
                                                T[] points,
                                                int degree,
                                                boolean continuous,
                                                T tmp)

Calculates the n-degree b-spline value for the given position (t).

Parameters:

out - The Vector to set to the result.

t - The position (0<=t<=1) on the spline

points - The control points

degree - The degree of the b-spline

continuous - If true the b-spline restarts at 0 when reaching 1

tmp - A temporary vector used for the calculation

Returns:

The value of out

derivative

public static <T extends Vector<T>> T derivative(T out,
                                                 float t,
                                                 T[] points,
                                                 int degree,
                                                 boolean continuous,
                                                 T tmp)

Calculates the n-degree b-spline derivative for the given position (t).

Parameters:

out - The Vector to set to the result.

t - The position (0<=t<=1) on the spline

points - The control points

degree - The degree of the b-spline

continuous - If true the b-spline restarts at 0 when reaching 1

tmp - A temporary vector used for the calculation

Returns:

The value of out

calculate

public static <T extends Vector<T>> T calculate(T out,
                                                int i,
                                                float u,
                                                T[] points,
                                                int degree,
                                                boolean continuous,
                                                T tmp)

Calculates the n-degree b-spline value for the given span (i) at the given position (u).

Parameters:

out - The Vector to set to the result.

i - The span (0<=i

u - The position (0<=u<=1) on the span

points - The control points

degree - The degree of the b-spline, only 3 is supported

continuous - If true the b-spline restarts at 0 when reaching 1

tmp - A temporary vector used for the calculation

Returns:

The value of out

derivative

public static <T extends Vector<T>> T derivative(T out,
                                                 int i,
                                                 float u,
                                                 T[] points,
                                                 int degree,
                                                 boolean continuous,
                                                 T tmp)

Calculates the n-degree b-spline derivative for the given span (i) at the given position (u).

Parameters:

out - The Vector to set to the result.

i - The span (0<=i

u - The position (0<=u<=1) on the span

points - The control points

degree - The degree of the b-spline, only 3 is supported

continuous - If true the b-spline restarts at 0 when reaching 1

tmp - A temporary vector used for the calculation

Returns:

The value of out

set

public BSpline set(T[] controlPoints,
                   int degree,
                   boolean continuous)

valueAt

public T valueAt(T out,
                 float t)

Specified by:

valueAt in interface Path<T extends Vector<T>>

Returns:

The value of the path at t where 0<=t<=1

valueAt

public T valueAt(T out,
                 int span,
                 float u)

Returns:

The value of the spline at position u of the specified span

derivativeAt

public T derivativeAt(T out,
                      float t)

Specified by:

derivativeAt in interface Path<T extends Vector<T>>

derivativeAt

public T derivativeAt(T out,
                      int span,
                      float u)

Returns:

The derivative of the spline at position u of the specified span

nearest

public int nearest(T in)

Returns:

The span closest to the specified value

nearest

public int nearest(T in,
                   int start,
                   int count)

Returns:

The span closest to the specified value, restricting to the specified spans.

approximate

public float approximate(T v)

Specified by:

approximate in interface Path<T extends Vector<T>>

Returns:

The approximated value (between 0 and 1) on the path which is closest to the specified value. Note that the implementation of this method might be optimized for speed against precision, see Path.locate(Object) for a more precise (but more intensive) method.

approximate

public float approximate(T in,
                         int start,
                         int count)

approximate

public float approximate(T in,
                         int near)

locate

public float locate(T v)

Specified by:

locate in interface Path<T extends Vector<T>>

Returns:

The precise location (between 0 and 1) on the path which is closest to the specified value. Note that the implementation of this method might be CPU intensive, see Path.approximate(Object) for a faster (but less precise) method.

approxLength

public float approxLength(int samples)

Specified by:

approxLength in interface Path<T extends Vector<T>>

Parameters:

samples - The amount of divisions used to approximate length. Higher values will produce more precise results, but will be more CPU intensive.

Returns:

An approximated length of the spline through sampling the curve and accumulating the euclidean distances between the sample points.