First checkin for OpenMesh 2.0

git-svn-id: http://www.openmesh.org/svnrepo/OpenMesh/trunk@2 fdac6126-5c0c-442c-9429-916003d36597

Tools/Decimater/ModNormalFlippingT.hh

@@ -0,0 +1,175 @@
+//=============================================================================
+//                                                                            
+//                               OpenMesh                                     
+//        Copyright (C) 2003 by Computer Graphics Group, RWTH Aachen          
+//                           www.openmesh.org                                 
+//                                                                            
+//-----------------------------------------------------------------------------
+//                                                                            
+//                                License                                     
+//                                                                            
+//   This library 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, version 2.1.                           
+//                                                                             
+//   This library 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 Lesser General Public          
+//   License along with this library; if not, write to the Free Software       
+//   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.                 
+//                                                                            
+//-----------------------------------------------------------------------------
+//                                                                            
+//   $Revision: 1802 $
+//   $Date: 2008-05-19 11:55:07 +0200 (Mo, 19. Mai 2008) $
+//                                                                            
+//=============================================================================
+
+/** \file ModNormalFlippingT.hh
+    
+ */
+
+//=============================================================================
+//
+//  CLASS ModNormalFlipping
+//
+//=============================================================================
+
+
+#ifndef OPENMESH_DECIMATER_MODNORMALFLIPPING_HH
+#define OPENMESH_DECIMATER_MODNORMALFLIPPING_HH
+
+
+//== INCLUDES =================================================================
+
+#include <OpenMesh/Tools/Decimater/ModBaseT.hh>
+
+//== NAMESPACES ===============================================================
+
+namespace OpenMesh { // BEGIN_NS_OPENMESH
+namespace Decimater { // BEGIN_NS_DECIMATER
+
+
+//== CLASS DEFINITION =========================================================
+
+/** Decimating module to avoid flipping of faces.
+ *  
+ *  This module can be used only as a binary module. The criterion
+ *  of allowing/disallowing the collapse is the angular deviation between
+ *  the face normal of the orignal faces and normals of the faces after the
+ *  collapse. The collapse will pass the test, if the deviation is below
+ *  a given threshold.
+ */	      
+template <typename DecimaterT>
+class ModNormalFlippingT : public ModBaseT< DecimaterT >
+{ 
+public:
+
+  DECIMATING_MODULE( ModNormalFlippingT, DecimaterT, NormalFlipping );
+
+public:
+  
+  /// Constructor
+  ModNormalFlippingT( DecimaterT &_dec) : Base(_dec, true)
+  {
+    set_max_normal_deviation( 90.0f );
+  }
+  
+
+  ~ModNormalFlippingT() 
+  { }
+  
+
+public:
+  
+  /** Compute collapse priority due to angular deviation of face normals
+   *  before and after a collapse.
+   *
+   *  -# Compute for each adjacent face of \c _ci.v0 the face
+   *  normal if the collpase would be executed.  
+   *
+   *  -# Prevent the collapse, if the angle between the original and the
+   *  new normal is below a given threshold.
+   *  
+   *  \param _ci The collapse description
+   *  \return LEGAL_COLLAPSE or ILLEGAL_COLLAPSE
+   *
+   *  \see set_max_normal_deviation()
+   */
+  float collapse_priority(const CollapseInfo& _ci)
+  {
+    // simulate collapse
+    Base::mesh().set_point(_ci.v0, _ci.p1);
+    
+    // check for flipping normals
+    typename Mesh::ConstVertexFaceIter vf_it(Base::mesh(), _ci.v0);
+    typename Mesh::FaceHandle          fh;
+    typename Mesh::Scalar              c(1.0);
+    
+    for (; vf_it; ++vf_it) 
+    {
+      fh = vf_it.handle();
+      if (fh != _ci.fl && fh != _ci.fr)
+      {
+        typename Mesh::Normal n1 = Base::mesh().normal(fh);
+        typename Mesh::Normal n2 = Base::mesh().calc_face_normal(fh);
+
+        c = dot(n1, n2);
+        
+        if (c < min_cos_)
+          break;
+      }
+    }
+      
+    // undo simulation changes
+    Base::mesh().set_point(_ci.v0, _ci.p0);
+
+    return float( (c < min_cos_) ? Base::ILLEGAL_COLLAPSE : Base::LEGAL_COLLAPSE );
+  }
+
+
+
+public:
+   
+  /// get normal deviation
+  float max_normal_deviation() const { return max_deviation_ / M_PI * 180.0; }
+  
+  /// \deprecated
+  float normal_deviation() const { return max_normal_deviation(); }
+  
+  /** Set normal deviation
+   *  
+   *  Set the maximum angular deviation of the orignal normal and the new
+   *  normal in degrees.
+   */
+  void set_max_normal_deviation(float _f) { 
+    max_deviation_ = _f / 180.0 * M_PI; 
+    min_cos_       = cos(max_deviation_);
+  }
+
+  /// \deprecated
+  void set_normal_deviation(float _f) 
+  { set_max_normal_deviation(_f); }
+  
+private:
+
+  // hide this method
+  void set_binary(bool _b) {}
+   
+private:
+
+  // maximum normal deviation
+  double max_deviation_, min_cos_;
+};
+
+
+//=============================================================================
+} // END_NS_DECIMATER
+} // END_NS_OPENMESH
+//=============================================================================
+#endif // OPENACG_MODNORMALFLIPPING_HH defined
+//=============================================================================
+