/*
* The JTS Topology Suite is a collection of Java classes that
* implement the fundamental operations required to validate a given
* geo-spatial data set to a known topological specification.
*
* Copyright (C) 2001 Vivid Solutions
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* For more information, contact:
*
* Vivid Solutions
* Suite #1A
* 2328 Government Street
* Victoria BC V8T 5G5
* Canada
*
* (250)385-6040
* www.vividsolutions.com
*/
package com.vividsolutions.jts.math;
import com.vividsolutions.jts.geom.Coordinate;
/**
* Models a plane in 3-dimensional Cartesian space.
*
* @author mdavis
*
*/
public class Plane3D {
/**
* Enums for the 3 coordinate planes
*/
public static final int XY_PLANE = 1;
public static final int YZ_PLANE = 2;
public static final int XZ_PLANE = 3;
private Vector3D normal;
private Coordinate basePt;
public Plane3D(Vector3D normal, Coordinate basePt)
{
this.normal = normal;
this.basePt = basePt;
}
/**
* Computes the oriented distance from a point to the plane.
* The distance is:
* <ul>
* <li><b>positive</b> if the point lies above the plane (relative to the plane normal)
* <li><b>zero</b> if the point is on the plane
* <li><b>negative</b> if the point lies below the plane (relative to the plane normal)
* </ul>
*
* @param p the point to compute the distance for
* @return the oriented distance to the plane
*/
public double orientedDistance(Coordinate p) {
Vector3D pb = new Vector3D(p, basePt);
double pbdDotNormal = pb.dot(normal);
if (Double.isNaN(pbdDotNormal))
throw new IllegalArgumentException("3D Coordinate has NaN ordinate");
double d = pbdDotNormal / normal.length();
return d;
}
/**
* Computes the axis plane that this plane lies closest to.
* <p>
* Geometries lying in this plane undergo least distortion
* (and have maximum area)
* when projected to the closest axis plane.
* This provides optimal conditioning for
* computing a Point-in-Polygon test.
*
* @return the index of the closest axis plane.
*/
public int closestAxisPlane() {
double xmag = Math.abs(normal.getX());
double ymag = Math.abs(normal.getY());
double zmag = Math.abs(normal.getZ());
if (xmag > ymag) {
if (xmag > zmag)
return YZ_PLANE;
else
return XY_PLANE;
}
// y >= x
else if (zmag > ymag) {
return XY_PLANE;
}
// y >= z
return XZ_PLANE;
}
}