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1   // ******************************************************************************
2   //
3   // Title:       Force Field X.
4   // Description: Force Field X - Software for Molecular Biophysics.
5   // Copyright:   Copyright (c) Michael J. Schnieders 2001-2025.
6   //
7   // This file is part of Force Field X.
8   //
9   // Force Field X is free software; you can redistribute it and/or modify it
10  // under the terms of the GNU General Public License version 3 as published by
11  // the Free Software Foundation.
12  //
13  // Force Field X is distributed in the hope that it will be useful, but WITHOUT
14  // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
15  // FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
16  // details.
17  //
18  // You should have received a copy of the GNU General Public License along with
19  // Force Field X; if not, write to the Free Software Foundation, Inc., 59 Temple
20  // Place, Suite 330, Boston, MA 02111-1307 USA
21  //
22  // Linking this library statically or dynamically with other modules is making a
23  // combined work based on this library. Thus, the terms and conditions of the
24  // GNU General Public License cover the whole combination.
25  //
26  // As a special exception, the copyright holders of this library give you
27  // permission to link this library with independent modules to produce an
28  // executable, regardless of the license terms of these independent modules, and
29  // to copy and distribute the resulting executable under terms of your choice,
30  // provided that you also meet, for each linked independent module, the terms
31  // and conditions of the license of that module. An independent module is a
32  // module which is not derived from or based on this library. If you modify this
33  // library, you may extend this exception to your version of the library, but
34  // you are not obligated to do so. If you do not wish to do so, delete this
35  // exception statement from your version.
36  //
37  // ******************************************************************************
38  package ffx.numerics.quickhull;
39  
40  /**
41   * Represents vertices of the hull, as well as the points from which it is
42   * formed.
43   *
44   * @author John E. Lloyd, Fall 2004
45   * @author Michael J. Schnieders
46   * @since 1.0
47   */
48  public class Vertex {
49  
50    /**
51     * Spatial point associated with this vertex.
52     */
53    Point3d pnt;
54  
55    /**
56     * Back index into an array.
57     */
58    int index;
59  
60    /**
61     * List forward link.
62     */
63    Vertex prev;
64  
65    /**
66     * List backward link.
67     */
68    Vertex next;
69  
70    /**
71     * Current face that this vertex is outside of.
72     */
73    Face face;
74  
75    /**
76     * Constructs a vertex and sets its coordinates to 0.
77     */
78    public Vertex() {
79      pnt = new Point3d();
80    }
81  
82    /**
83     * Constructs a vertex with the specified coordinates and index.
84     *
85     * @param x   x-coordinate of the vertex
86     * @param y   y-coordinate of the vertex
87     * @param z   z-coordinate of the vertex
88     * @param idx index associated with the vertex in an external array
89     */
90    public Vertex(double x, double y, double z, int idx) {
91      pnt = new Point3d(x, y, z);
92      index = idx;
93    }
94  
95  }