/*
RepRap
------
The Replicating Rapid Prototyper Project
Copyright (C) 2005
Adrian Bowyer & The University of Bath
http://reprap.org
Principal author:
Adrian Bowyer
Department of Mechanical Engineering
Faculty of Engineering and Design
University of Bath
Bath BA2 7AY
U.K.
e-mail: A.Bowyer@bath.ac.uk
RepRap is free; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
Licence as published by the Free Software Foundation; either
version 2 of the Licence, or (at your option) any later version.
RepRap 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
Library General Public Licence for more details.
For this purpose the words "software" and "library" in the GNU Library
General Public Licence are taken to mean any and all computer programs
computer files data results documents and other copyright information
available from the RepRap project.
You should have received a copy of the GNU Library General Public
Licence along with RepRap; if not, write to the Free
Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA,
or see
http://www.gnu.org/
=====================================================================
RrRectangle: 2D rectangles
First version 20 May 2005
This version: 1 May 2006 (Now in CVS - no more comments here)
*/
package org.reprap.geometry.polyhedra;
import org.reprap.geometry.polygons.Interval;
/**
* A 2D box is an X and a Y interval
*/
public class Box
{
/**
* Compass directions
*/
public static final byte rr_N = 1;
public static final byte rr_E = 2;
public static final byte rr_S = 4;
public static final byte rr_W = 8;
public static final byte rr_U = 16;
public static final byte rr_D = 32;
/**
* X interval
*/
private Interval x = null;
/**
* Y interval
*/
private Interval y = null;
/**
* Z interval
*/
private Interval z = null;
/**
* Anyone home?
*/
private boolean empty;
/**
* Default is empty
*/
public Box()
{
empty = true;
}
/**
* Copy constructor
*/
public Box(Box b)
{
x = new Interval(b.x);
y = new Interval(b.y);
z = new Interval(b.z);
empty = b.empty;
}
/**
* Make from any diagonal corners
* @param sw
* @param ne
*/
public Box(Point3D a, Point3D b)
{
x = new Interval(Math.min(a.x(), b.x()), Math.max(a.x(), b.x()));
y = new Interval(Math.min(a.y(), b.y()), Math.max(a.y(), b.y()));
y = new Interval(Math.min(a.z(), b.z()), Math.max(a.z(), b.z()));
empty = x.empty() || y.empty() || z.empty();
}
/**
* Make from X and Y intervals
* @param sw
* @param ne
*/
public Box(Interval xi, Interval yi, Interval zi)
{
x = new Interval(xi);
y = new Interval(yi);
z = new Interval(zi);
empty = x.empty() || y.empty() || z.empty();
}
/**
* @return Return the x interval
*/
public Interval x() { return x; }
/**
* @return Return the y interval
*
*/
public Interval y() { return y; }
/**
* @return Return the z interval
*
*/
public Interval z() { return z; }
/**
*
* @return
*/
public boolean empty() { return empty; }
/**
* Expand the box to incorporate another box or a point
* @param a
*/
public void expand(Box a)
{
if(a.empty)
return;
if(empty)
{
empty = false;
x = new Interval(a.x);
y = new Interval(a.y);
z = new Interval(a.z);
} else
{
x.expand(a.x);
y.expand(a.y);
z.expand(a.z);
}
}
/**
* Shrink or grow by a given distance
* @param dist
* @return
*/
public Box offset(double dist)
{
return new Box(new Interval(x.low() - dist, x.high() + dist),
new Interval(y.low() - dist, y.high() + dist),
new Interval(z.low() - dist, z.high() + dist));
}
/**
* Move somewhere else
* @param p
* @return
*/
public Box translate(Point3D p)
{
return new Box(new Interval(x.low() + p.x(), x.high() + p.x()),
new Interval(y.low() + p.y(), y.high() + p.y()),
new Interval(z.low() + p.z(), z.high() + p.z()));
}
/**
* @param a
*/
public void expand(Point3D a)
{
if(empty)
{
empty = false;
x = new Interval(a.x(), a.x());
y = new Interval(a.y(), a.y());
z = new Interval(a.z(), a.z());
} else
{
x.expand(a.x());
y.expand(a.y());
z.expand(a.z());
}
}
/**
* Corner points and center
* @return NE cornerpoint
*/
public Point3D nel()
{
return new Point3D(x.high(), y.high(), z.low());
}
public Point3D neh()
{
return new Point3D(x.high(), y.high(), z.high());
}
/**
* @return SW cornerpoint
*/
public Point3D swl()
{
return new Point3D(x.low(), y.low(), z.low());
}
public Point3D swh()
{
return new Point3D(x.low(), y.low(), z.high());
}
/**
* @return SE cornerpoint
*/
public Point3D sel()
{
return new Point3D(x.high(), y.low(), z.low());
}
public Point3D seh()
{
return new Point3D(x.high(), y.low(), z.high());
}
/**
* @return NW cornerpoint
*/
public Point3D nwl()
{
return new Point3D(x.low(), y.high(), z.low());
}
public Point3D nwh()
{
return new Point3D(x.low(), y.high(), z.high());
}
/**
* @return Centre point
*/
public Point3D centre()
{
return new Point3D(x.cen(), y.cen(), z.cen());
}
/**
* Scale the box by a factor about its center
* @param f
* @return scaled box object
*/
public Box scale(double f)
{
Box r = new Box();
if(empty)
return r;
f = 0.5*f;
Point3D p = new Point3D(x.length()*f, y.length()*f, z.length()*f);
Point3D c = centre();
r.expand(Point3D.add(c, p));
r.expand(Point3D.sub(c, p));
return r;
}
/**
* Convert to a string
*/
public String toString()
{
if(empty)
return "<empty>";
return "<BOX x:" + x.toString() + ", y:" + y.toString() + ", z:" + z.toString() + ">";
}
/**
* Squared diagonal
* @return squared diagonal of the box
*/
public double dSquared()
{
if(empty)
return 0;
return Point3D.dSquared(swl(), neh());
}
// /**
// * Squared distance to a point
// * @return minimal squared distance to a point from one of the corners of the box
// */
// public double dSquared(Point3D p)
// {
// if(empty)
// return Double.POSITIVE_INFINITY;
// byte b = pointRelative(p);
// double d1 = Double.POSITIVE_INFINITY, d2 = Double.POSITIVE_INFINITY;
// switch(b)
// {
// case 0:
// return 0;
//
// case 1:
// d1 = Point2D.dSquared(p, nw());
// d2 = Point2D.dSquared(p, ne());
// break;
//
// case 2:
// d1 = Point2D.dSquared(p, ne());
// d2 = Point2D.dSquared(p, se());
// break;
//
// case 3:
// return Point2D.dSquared(p, ne());
//
// case 4:
// d1 = Point2D.dSquared(p, sw());
// d2 = Point2D.dSquared(p, se());
// break;
//
// case 6:
// return Point2D.dSquared(p, se());
//
// case 8:
// d1 = Point2D.dSquared(p, sw());
// d2 = Point2D.dSquared(p, nw());
// break;
//
// case 9:
// return Point2D.dSquared(p, nw());
//
// case 12:
// return Point2D.dSquared(p, sw());
//
// default:
// Debug.e("RrRectangle.dSquared(): dud value from point_relative()!");
// }
//
// return Math.min(d1, d2);
//
// }
/**
* Where is a point relative to a box?
* @param p
* @return relative position of a point p (E, W, N or S)
*/
public byte pointRelative(Point3D p)
{
byte result = 0;
if(p.x() >= x.high())
result |= rr_E;
if(p.x() < x.low())
result |= rr_W;
if(p.y() >= y.high())
result |= rr_N;
if(p.y() < y.low())
result |= rr_S;
if(p.z() >= z.high())
result |= rr_U;
if(p.z() < z.low())
result |= rr_D;
return result;
}
/**
* Intersection
* @param a
* @param b
* @return
*/
public static Box intersection(Box a, Box b)
{
if(a.empty)
return a;
if(b.empty)
return b;
return new Box(Interval.intersection(a.x, b.x), Interval.intersection(a.y, b.y), Interval.intersection(a.z, b.z));
}
/**
* Union
* @param a
* @param b
* @return
*/
public static Box union(Box a, Box b)
{
if(a.empty)
return b;
if(b.empty)
return a;
return new Box(Interval.union(a.x, b.x), Interval.union(a.y, b.y), Interval.union(a.z, b.z));
}
}