001: /*
002: * $RCSfile: EdgeTable.java,v $
003: *
004: * Copyright (c) 2007 Sun Microsystems, Inc. All rights reserved.
005: *
006: * Redistribution and use in source and binary forms, with or without
007: * modification, are permitted provided that the following conditions
008: * are met:
009: *
010: * - Redistribution of source code must retain the above copyright
011: * notice, this list of conditions and the following disclaimer.
012: *
013: * - Redistribution in binary form must reproduce the above copyright
014: * notice, this list of conditions and the following disclaimer in
015: * the documentation and/or other materials provided with the
016: * distribution.
017: *
018: * Neither the name of Sun Microsystems, Inc. or the names of
019: * contributors may be used to endorse or promote products derived
020: * from this software without specific prior written permission.
021: *
022: * This software is provided "AS IS," without a warranty of any
023: * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
024: * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
025: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY
026: * EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL
027: * NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF
028: * USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
029: * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR
030: * ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL,
031: * CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND
032: * REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF OR
033: * INABILITY TO USE THIS SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
034: * POSSIBILITY OF SUCH DAMAGES.
035: *
036: * You acknowledge that this software is not designed, licensed or
037: * intended for use in the design, construction, operation or
038: * maintenance of any nuclear facility.
039: *
040: * $Revision: 1.4 $
041: * $Date: 2007/02/09 17:20:18 $
042: * $State: Exp $
043: */
044:
045: package com.sun.j3d.utils.geometry;
046:
047: import java.util.HashMap;
048: import java.util.Iterator;
049: import java.util.Set;
050: import com.sun.j3d.utils.geometry.Edge;
051:
052: class EdgeTable {
053:
054: private HashMap edgeTable;
055: private static final int DEBUG = 0;
056:
057: Integer get(int a, int b) {
058: return (Integer) edgeTable.get(new Edge(a, b));
059: } // End of get()
060:
061: Integer get(Edge e) {
062: return (Integer) edgeTable.get(e);
063: } // End of get()
064:
065: // This function creates a table used to connect the triangles.
066: // Here's how it works. If a triangle is made of indices 12,
067: // 40, and 51, then edge(12, 40) gets 51, edge(40, 51) gets 12,
068: // and edge(51, 12) gets 40. This lets us quickly move from
069: // triangle to triangle without saving a lot of extra data.
070: EdgeTable(int triangleIndices[]) {
071: // We'll have one edge for each vertex
072: edgeTable = new HashMap(triangleIndices.length * 2);
073:
074: // Fill in table
075: Edge e;
076: for (int t = 0; t < triangleIndices.length; t += 3) {
077: // Put all 3 edges of triangle into table
078: for (int v = 0; v < 3; v++) {
079: e = new Edge(triangleIndices[t + v], triangleIndices[t
080: + ((v + 1) % 3)]);
081:
082: if (edgeTable.get(e) != null) {
083: if ((DEBUG & 1) != 0) {
084: System.out
085: .println("EdgeTable Error: duplicate edge ("
086: + triangleIndices[t + v]
087: + ", "
088: + triangleIndices[t
089: + ((v + 1) % 3)] + ").");
090: }
091: } else {
092: // Store index of 3rd vertex (across from edge)
093: edgeTable.put(e, new Integer(t + ((v + 2) % 3)));
094: }
095: }
096: }
097:
098: if ((DEBUG & 1) != 0) {
099: System.out.println("Edge Table:");
100: Iterator list = edgeTable.keySet().iterator();
101: while (list.hasNext()) {
102: Edge edge = (Edge) list.next();
103: System.out.println(" (" + edge.v1 + ", " + edge.v2
104: + ") = " + get(edge.v1, edge.v2));
105: }
106: }
107: } // End of constructor EdgeTable
108:
109: } // End of class EdgeTable
110:
111: // End of file EdgeTable.java
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