hmi.math
Class HermiteSpline

java.lang.Object
  hmi.math.HermiteSpline

public final class HermiteSpline
extends Object

Hermite spline A cubic, acceleration-continu spline going fluently through equidistant (with distant 1) interpolation points. The acceleration in these points is calculated using Catmull-Rom: Px'=0.5*(P(x-1)-P(x+1))

Author:

Herwin van Welbergen

Field Summary

private float[]	interpolationPoints
private float	m0
private float	mn

Constructor Summary

HermiteSpline()
Constructor, m0, mn and interpolation points have to be set manually when this zero-argument constructor is used

HermiteSpline(float[] val)
Constructor, speed=0 at start and end points

HermiteSpline(float[] val, float startSpeed, float endSpeed)
Constructor

Method Summary

float	eval(float t) Get the interpolation value at time t
static float	getValue(float t, float p_1, float p0, float p1, float p2) Gets the value of the hermite spline at point p0 < t < p1
static float	getValueCustomSpeed(float t, float p0, float p1, float m0, float m1) Get the interpolation value for custom speed at interpolation points p0 and p1
private static double	H0(double t)
private static double	H1(double t)
private static double	H2(double t)
private static double	H3(double t)
void	setInterpolationPoints(float[] interpolationPoints)
void	setM0(float m0)
void	setMn(float mn)

Methods inherited from class java.lang.Object

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

Field Detail

interpolationPoints

private float[] interpolationPoints

m0

private float m0

mn

private float mn

Constructor Detail

HermiteSpline

public HermiteSpline()

Constructor, m0, mn and interpolation points have to be set manually when this zero-argument constructor is used

HermiteSpline

public HermiteSpline(float[] val)

Constructor, speed=0 at start and end points

Parameters:

val - points to interpolate through

HermiteSpline

public HermiteSpline(float[] val,
                     float startSpeed,
                     float endSpeed)

Constructor

Parameters:

val - points to interpolate through

startSpeed - speed at p0

endSpeed - speed at pn

Method Detail

H0

private static double H0(double t)

H1

private static double H1(double t)

H2

private static double H2(double t)

H3

private static double H3(double t)

eval

public float eval(float t)

Get the interpolation value at time t

Parameters:

t - time

Returns:

the interpolation value, interpolationPoints[interpolationPoints.length-1] if t >= interpolationPoints.length-1

getValueCustomSpeed

public static float getValueCustomSpeed(float t,
                                        float p0,
                                        float p1,
                                        float m0,
                                        float m1)

Get the interpolation value for custom speed at interpolation points p0 and p1

Parameters:

t - time 0<=t<=1

p0 - 1st interpolation point

p1 - 2nd interpolation point

m0 - speed at p0

m1 - speed at p1

Returns:

the interpolation value

getValue

public static float getValue(float t,
                             float p_1,
                             float p0,
                             float p1,
                             float p2)

Gets the value of the hermite spline at point p0 < t < p1

Parameters:

t - time

p_1 - point p-1

p0 - point p0

p1 - point p1

p2 - point p2

Returns:

the interpolation value

setInterpolationPoints

public void setInterpolationPoints(float[] interpolationPoints)

Parameters:

interpolationPoints - The interpolationPoints to set.

setM0

public void setM0(float m0)

Parameters:

m0 - The m0 to set.

setMn

public void setMn(float mn)

Parameters:

mn - The mn to set.