maspack.geometry

Class NURBSCurve3d

java.lang.Object

maspack.geometry.NURBSObject

maspack.geometry.NURBSCurveBase

maspack.geometry.NURBSCurve3d

All Implemented Interfaces:

HasRenderProps, IsRenderable, IsSelectable, Renderable

public class NURBSCurve3d
extends NURBSCurveBase

Implements a NURBS curve

Field Summary

Fields inherited from class maspack.geometry.NURBSCurveBase

CLOSED, init, OPEN

Fields inherited from interface maspack.render.IsRenderable

TRANSPARENT, TWO_DIMENSIONAL

Constructor Summary

Constructors

Constructor and Description
NURBSCurve3d() Creates an empty NURBS curve.
NURBSCurve3d(int d, int type, Vector4d[] ctrlPnts, double[] knots) Creates an open or closed NURBS curve with a specified degree, knots, and control points.

Method Summary

Modifier and Type	Method and Description
void	eval(Point3d pnt, double u) Evaluates the point on this curve for parameter u.
Point3d[]	evalPoints(int npnts) Returns a set of points evaluated along the curve at intervals which are evenly spaced with respect to the curve parameter.
double	findPoint(Point3d pnt, double umin, double umax) Finds a u value for a given curve point within a specified interval of the curve.
void	set(NURBSCurve3d curve)

Methods inherited from class maspack.geometry.NURBSCurveBase

addControlPoint, computeControlPolygonLength, convertToBezier, createRenderProps, createUniformKnots, getDegree, getKnot, getKnotIndex, getKnots, getRange, getResolution, getType, insertKnot, isBezier, isBSpline, isClosed, numKnots, read, read, removeControlPoint, render, reset, set, set, set, setBezier, setCircle, setRange, setResolution, setUniformCubic, write, write

Methods inherited from class maspack.geometry.NURBSObject

controlPointIsSelected, getControlPoint, getControlPoints, getDrawControlShape, getLineWidth, getObjToWorld, getObjToWorld, getPointSize, getRenderHints, getRenderProps, getSelection, isSelectable, numControlPoints, numSelectionQueriesNeeded, prerender, render, selectControlPoint, setDrawControlShape, setLineWidth, setObjToWorld, setPointSize, setRenderProps, transform, updateBounds, write, write

Methods inherited from class java.lang.Object

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

Constructor Detail

NURBSCurve3d

public NURBSCurve3d()

Creates an empty NURBS curve.

NURBSCurve3d

public NURBSCurve3d(int d,
                    int type,
                    Vector4d[] ctrlPnts,
                    double[] knots)

Creates an open or closed NURBS curve with a specified degree, knots, and control points. For more information on these arguments, see set.

Parameters:

d - degree of the curve

type - curve type, which must be either OPEN or CLOSED.

ctrlPnts - control points

knots - knot values

Throws:

java.lang.IllegalArgumentException - if constraints on the arguments are violated

See Also:

NURBSCurveBase.set(int,int,Vector4d[],double[])

Method Detail

evalPoints

public Point3d[] evalPoints(int npnts)

Returns a set of points evaluated along the curve at intervals which are evenly spaced with respect to the curve parameter.

Parameters:

npnts - number of points to create

Returns:

array of evaluated points

eval

public void eval(Point3d pnt,
                 double u)

Evaluates the point on this curve for parameter u. If necessary, u is clipped to the range [ustart, uend].

Specified by:

eval in class NURBSCurveBase

Parameters:

pnt - returns the curve point value

u - curve parameter value

findPoint

public double findPoint(Point3d pnt,
                        double umin,
                        double umax)

Finds a u value for a given curve point within a specified interval of the curve. If the point is not actually on the specified interval, this routine attempts to return the u value for the nearest curve point. It should be noted that one point may correspond to multiple u values.

This routine uses an iterative golden section search, and so is not particularly fast.

Parameters:

pnt - point to search for

umin - minimum u valu for the interval

umax - maximum u valu for the interval

Returns:

u value for the point closest to pnt within the interval.

set

public void set(NURBSCurve3d curve)