maspack.geometry

Class ConvexPolygon3d

java.lang.Object

maspack.geometry.Polygon3d

maspack.geometry.ConvexPolygon3d

All Implemented Interfaces:

java.lang.Iterable<PolygonVertex3d>

public class ConvexPolygon3d
extends Polygon3d

Constructor Summary

Constructors

Constructor and Description
ConvexPolygon3d()
ConvexPolygon3d(double[] coords)
ConvexPolygon3d(Point3d[] pnts)

Method Summary

Modifier and Type	Method and Description
double	area()
<P extends Point3d> void	computeAndSetHull(java.util.List<P> input, Vector3d nrml, double angTol) Computes the convex hull, with respect to a given normal direction, of a set of input points, and places its contents in this Polygon3d.
void	computeCentroid(Vector3d centroid)
static <P extends Point3d> java.util.ArrayList<P>	computeHull(java.util.List<P> input, Vector3d nrml, double angTol) Computes the convex hull, with respect to a given normal direction, of a set of input points.
static <P extends Point3d> int[]	computeHullIndices(java.util.List<P> input, Vector3d nrml, double angTol) Computes the indices of the convex hull, with respect to a given normal direction, of a set of input points.
void	computeNormal(Vector3d nrm)
static <P extends Point3d> java.util.ArrayList<P>	computeOld(java.util.Collection<P> input, Vector3d nrml, double tol) Computes the convex hull, with respect to a given normal direction, of a set of input points.
double	getTolerance()
void	intersectHalfSpace(Plane plane)
void	setTolerance(double tol)

Methods inherited from class maspack.geometry.Polygon3d

addVertexAfter, appendVertex, clear, computeCentroid, computePlanarArea, epsilonEquals, equals, getBounds, getFirstVertex, getLastVertex, getMaxCoordinate, getPoints, getVertices, inverseTransform, isConvex, isConvex, isEmpty, iterator, numVertices, prependVertex, scan, set, set, set, set, toString, toString, toString, transform, updateBounds

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

ConvexPolygon3d

public ConvexPolygon3d()

ConvexPolygon3d

public ConvexPolygon3d(double[] coords)

ConvexPolygon3d

public ConvexPolygon3d(Point3d[] pnts)

Method Detail

getTolerance

public double getTolerance()

setTolerance

public void setTolerance(double tol)

area

public double area()

computeCentroid

public void computeCentroid(Vector3d centroid)

intersectHalfSpace

public void intersectHalfSpace(Plane plane)

computeNormal

public void computeNormal(Vector3d nrm)

computeOld

public static <P extends Point3d> java.util.ArrayList<P> computeOld(java.util.Collection<P> input,
                                                                    Vector3d nrml,
                                                                    double tol)

Computes the convex hull, with respect to a given normal direction, of a set of input points. In other words, the points are culled such their projection into the plane defined by the normal forms a convex hull in that plane. Te algorithm is based on a 3D version of the Graham Scan algorithm, which is O(n log n).

computeHullIndices

public static <P extends Point3d> int[] computeHullIndices(java.util.List<P> input,
                                                           Vector3d nrml,
                                                           double angTol)

Computes the indices of the convex hull, with respect to a given normal direction, of a set of input points. See computeHull(java.util.List<P>, maspack.matrix.Vector3d, double) for details.

Parameters:

input - points from which to compute the hull

nrml - normal vector for the plane with respect to which the hull should be computed

angTol - if > 0, specifies an angular tolerance which should be used to remove nearly colinear points

Returns:

list of the indices of the point in input which form the hull, in counter-clockwise order

computeHull

public static <P extends Point3d> java.util.ArrayList<P> computeHull(java.util.List<P> input,
                                                                     Vector3d nrml,
                                                                     double angTol)

Computes the convex hull, with respect to a given normal direction, of a set of input points. The algorithm works by projecting the points into a plane associated with the normal, and then computing the indices of the 2D convex hull in that plane, using ConvexPolygon2d.computeHullIndices(java.util.Collection<maspack.matrix.Point2d>, double). Point values along the normal are ignored.

Parameters:

input - points from which to compute the hull

nrml - normal vector for the plane with respect to which the hull should be computed

angTol - if > 0, specifies an angular tolerance which should be used to remove nearly colinear points

Returns:

a list of points, copied from input, which form the hull in counter-clockwise order

computeAndSetHull

public <P extends Point3d> void computeAndSetHull(java.util.List<P> input,
                                                  Vector3d nrml,
                                                  double angTol)

Computes the convex hull, with respect to a given normal direction, of a set of input points, and places its contents in this Polygon3d. See computeHull(List,Vector3d,double) for details.

Parameters:

input - points from which to compute the hull

nrml - normal vector for the plane with respect to which the hull should be computed

angTol - if > 0, specifies an angular tolerance which should be used to remove nearly colinear points