Initial revision.

src/Lib/Optimize/genstrips.cxx

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+// genstrips.cxx -- Optimize a collection of individual triangles into
+//                  strips.
+//
+// Written by Curtis Olson, started May 2000.
+//
+// Copyright (C) 2000  Curtis L. Olson  - curt@flightgear.org
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of the
+// License, or (at your option) any later version.
+//
+// This program 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
+// General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+//
+// $Id$
+
+
+#include <simgear/compiler.h>
+
+#include "genstrips.hxx"
+
+
+// make sure the list is expanded at least to hold "n" and then push
+// "i" onto the back of the "n" list.
+static void add_and_expand( opt_list& by_node, int n, int i ) {
+    int_list empty;
+
+    int size = (int)by_node.size();
+    if ( size > n ) {
+	// ok
+    } else {
+	// cout << "capacity = " << by_node.capacity() << endl;
+	// cout << "size = " << size << "  n = " << n
+	//      << " need to push = " << n - size + 1 << endl;
+	for ( int i = 0; i < n - size + 1; ++i ) {
+	    by_node.push_back(empty);
+	}
+    }
+
+    by_node[n].push_back(i);
+}
+
+
+// generate a set of tri-strips from a random collection of triangles.
+// Note, the triangle verticies are integer indices into a vertex list
+// and not actual vertex data.
+opt_list tgGenStrips( const triele_list tris ) {
+
+    triele_list remaining = tris;
+
+    while ( remaining.size() ) {
+	// traverse the triangle list and for each node, build a list of
+	// triangles that attach to it.
+
+	// cout << "building by_node list" << endl;
+	opt_list by_node;
+	by_node.clear();
+
+	for ( int i = 0; i < (int)remaining.size(); ++i ) {
+	    int n1 = remaining[i].get_n1();
+	    int n2 = remaining[i].get_n2();
+	    int n3 = remaining[i].get_n3();
+
+	    add_and_expand( by_node, n1, i );
+	    add_and_expand( by_node, n2, i );
+	    add_and_expand( by_node, n3, i );
+	}
+
+	// find the least connected triangle (this is a popular
+	// heuristic for starting finding a good set of triangle
+	// strips.)
+
+	int min_size = 32768;
+	int min_tri = -1;
+	for ( int i = 0; i < (int)remaining.size(); ++i ) {
+	    int n1 = remaining[i].get_n1();
+	    int n2 = remaining[i].get_n2();
+	    int n3 = remaining[i].get_n3();
+	    int metric = 0;
+
+	    metric += by_node[n1].size();
+	    metric += by_node[n2].size();
+	    metric += by_node[n3].size();
+
+	    if ( metric < min_size ) {
+		min_size = metric;
+		min_tri = i;
+	    }
+	}
+    }
+}
+
+

src/Lib/Optimize/genstrips.hxx

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+// genstrips.hxx -- Optimize a collection of individual triangles into
+//                  strips.
+//
+// Written by Curtis Olson, started May 2000.
+//
+// Copyright (C) 2000  Curtis L. Olson  - curt@flightgear.org
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of the
+// License, or (at your option) any later version.
+//
+// This program 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
+// General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+//
+// $Id$
+
+
+#ifndef _GENSTRIPS_HXX
+#define _GENSTRIPS_HXX
+
+
+#ifndef __cplusplus                                                          
+# error This library requires C++
+#endif                                   
+
+
+#include <simgear/compiler.h>
+
+#include <vector>
+
+#include <simgear/math/fg_types.hxx>
+
+#include <Triangulate/trieles.hxx>
+
+FG_USING_STD(vector);
+
+
+typedef vector < int_list > opt_list;
+typedef opt_list::iterator opt_list_iterator;
+typedef opt_list::const_iterator const_opt_list_iterator;
+
+
+// generate a set of tri-strips from a random collection of triangles.
+// Note, the triangle verticies are integer indices into a vertex list
+// and not actual vertex data.
+opt_list tgGenStrips( const triele_list tris );
+
+
+#endif // _GENSTRIPS_HXX
+
+