- added random number generator to Core/Utils that generates a double between 0.0 and 1.0 with garantueed precision

- use this random number generator for the McDecimater under Windows, since RAND_MAX is not large enough

git-svn-id: http://www.openmesh.org/svnrepo/OpenMesh/trunk@713 fdac6126-5c0c-442c-9429-916003d36597

src/OpenMesh/Core/Utils/RandomNumberGenerator.cc

@@ -0,0 +1,95 @@
+/*===========================================================================*\
+ *                                                                           *
+ *                               OpenMesh                                    *
+ *      Copyright (C) 2001-2011 by Computer Graphics Group, RWTH Aachen      *
+ *                           www.openmesh.org                                *
+ *                                                                           *
+ *---------------------------------------------------------------------------* 
+ *  This file is part of OpenMesh.                                           *
+ *                                                                           *
+ *  OpenMesh 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 3 of           *
+ *  the License, or (at your option) any later version with the              *
+ *  following exceptions:                                                    *
+ *                                                                           *
+ *  If other files instantiate templates or use macros                       *
+ *  or inline functions from this file, or you compile this file and         *
+ *  link it with other files to produce an executable, this file does        *
+ *  not by itself cause the resulting executable to be covered by the        *
+ *  GNU Lesser General Public License. This exception does not however       *
+ *  invalidate any other reasons why the executable file might be            *
+ *  covered by the GNU Lesser General Public License.                        *
+ *                                                                           *
+ *  OpenMesh 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 LesserGeneral Public          *
+ *  License along with OpenMesh.  If not,                                    *
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+ *                                                                           *
+\*===========================================================================*/ 
+
+/*===========================================================================*\
+ *                                                                           *             
+ *   $Revision: 362 $                                                         *
+ *   $Date: 2011-01-26 10:21:12 +0100 (Mi, 26 Jan 2011) $                   *
+ *                                                                           *
+\*===========================================================================*/
+
+
+//=============================================================================
+//
+//  Helper Functions for generating a random number between 0.0 and 1.0 with
+//  a garantueed resolution
+//
+//=============================================================================
+
+
+//== INCLUDES =================================================================
+
+
+#include <OpenMesh/Core/Utils/RandomNumberGenerator.hh>
+
+
+//== NAMESPACES ===============================================================
+
+
+namespace OpenMesh {
+
+
+//== IMPLEMENTATION ===========================================================
+
+RandomNumberGenerator::RandomNumberGenerator(const double _resolution) :
+  resolution_(_resolution),
+  iterations_(1),
+  maxNum_(RAND_MAX)
+{
+  double tmp = resolution_;
+  while (tmp > (double(RAND_MAX) + 1) ) {
+    iterations_++;
+    tmp /= (double(RAND_MAX) + 1);
+  } 
+
+  for ( unsigned int i = 0 ; i < iterations_ - 1; ++i ) {
+    maxNum_ *= (RAND_MAX + 1);
+  }
+}
+
+//-----------------------------------------------------------------------------
+
+double RandomNumberGenerator::getRand() const {
+  double randNum = 0.0;
+  for ( unsigned int i = 0 ; i < iterations_; ++i ) {
+    randNum *= (RAND_MAX + 1);
+    randNum += rand();
+  }
+
+  return randNum / maxNum_;
+}
+   
+//=============================================================================
+} // namespace OpenMesh
+//=============================================================================