Added tutorial on deleting geometry

git-svn-id: http://www.openmesh.org/svnrepo/OpenMesh/trunk@156 fdac6126-5c0c-442c-9429-916003d36597

Doc/Tutorial/07b-delete_geometry/delete_geometry.cc

+//=============================================================================
+//                                                                            
+//                               OpenMesh                                     
+//      Copyright (C) 2001-2005 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 Library General Public License as published  
+//   by the Free Software Foundation, version 2.                             
+//                                                                             
+//   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         
+//   Library General Public License for more details.                          
+//                                                                            
+//   You should have received a copy of the GNU Library General Public         
+//   License along with this library; if not, write to the Free Software       
+//   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.                 
+//                                                                            
+//-----------------------------------------------------------------------------
+//                                                                            
+//   $Revision: 83 $
+//   $Date: 2009-02-27 17:31:45 +0100 (Fri, 27 Feb 2009) $
+//                                                                            
+//=============================================================================
+
+
+#include <iostream>
+// -------------------- OpenMesh
+#include <OpenMesh/Core/IO/MeshIO.hh>
+#include <OpenMesh/Core/Mesh/PolyMesh_ArrayKernelT.hh>
+#include <OpenMesh/Core/System/config.h>
+#include <OpenMesh/Core/Mesh/Status.hh>
+
+// ----------------------------------------------------------------------------
+
+struct MyTraits : public OpenMesh::DefaultTraits
+{
+  VertexAttributes(OpenMesh::Attributes::Status);
+  FaceAttributes(OpenMesh::Attributes::Status);
+  EdgeAttributes(OpenMesh::Attributes::Status);
+};
+
+
+typedef OpenMesh::PolyMesh_ArrayKernelT<MyTraits>  MyMesh;
+
+
+// ----------------------------------------------------------------------------
+// Build a simple cube and delete it except one face
+  
+int main()
+{
+  MyMesh mesh;
+
+  // generate vertices
+
+  MyMesh::VertexHandle vhandle[8];
+  MyMesh::FaceHandle   fhandle[6];
+
+  vhandle[0] = mesh.add_vertex(MyMesh::Point(-1, -1,  1));
+  vhandle[1] = mesh.add_vertex(MyMesh::Point( 1, -1,  1));
+  vhandle[2] = mesh.add_vertex(MyMesh::Point( 1,  1,  1));
+  vhandle[3] = mesh.add_vertex(MyMesh::Point(-1,  1,  1));
+  vhandle[4] = mesh.add_vertex(MyMesh::Point(-1, -1, -1));
+  vhandle[5] = mesh.add_vertex(MyMesh::Point( 1, -1, -1));
+  vhandle[6] = mesh.add_vertex(MyMesh::Point( 1,  1, -1));
+  vhandle[7] = mesh.add_vertex(MyMesh::Point(-1,  1, -1));
+
+
+  // generate (quadrilateral) faces
+
+  std::vector<MyMesh::VertexHandle>  tmp_face_vhandles;
+
+  tmp_face_vhandles.clear();
+  tmp_face_vhandles.push_back(vhandle[0]);
+  tmp_face_vhandles.push_back(vhandle[1]);
+  tmp_face_vhandles.push_back(vhandle[2]);
+  tmp_face_vhandles.push_back(vhandle[3]);
+  fhandle[0] = mesh.add_face(tmp_face_vhandles);
+ 
+  tmp_face_vhandles.clear();
+  tmp_face_vhandles.push_back(vhandle[7]);
+  tmp_face_vhandles.push_back(vhandle[6]);
+  tmp_face_vhandles.push_back(vhandle[5]);
+  tmp_face_vhandles.push_back(vhandle[4]);
+  fhandle[1] = mesh.add_face(tmp_face_vhandles);
+ 
+  tmp_face_vhandles.clear();
+  tmp_face_vhandles.push_back(vhandle[1]);
+  tmp_face_vhandles.push_back(vhandle[0]);
+  tmp_face_vhandles.push_back(vhandle[4]);
+  tmp_face_vhandles.push_back(vhandle[5]);
+  fhandle[2] = mesh.add_face(tmp_face_vhandles);
+ 
+
+  tmp_face_vhandles.clear();
+  tmp_face_vhandles.push_back(vhandle[2]);
+  tmp_face_vhandles.push_back(vhandle[1]);
+  tmp_face_vhandles.push_back(vhandle[5]);
+  tmp_face_vhandles.push_back(vhandle[6]);
+  fhandle[3] = mesh.add_face(tmp_face_vhandles);
+
+
+  tmp_face_vhandles.clear();
+  tmp_face_vhandles.push_back(vhandle[3]);
+  tmp_face_vhandles.push_back(vhandle[2]);
+  tmp_face_vhandles.push_back(vhandle[6]);
+  tmp_face_vhandles.push_back(vhandle[7]);
+  fhandle[4] = mesh.add_face(tmp_face_vhandles);
+ 
+
+  tmp_face_vhandles.clear();
+  tmp_face_vhandles.push_back(vhandle[0]);
+  tmp_face_vhandles.push_back(vhandle[3]);
+  tmp_face_vhandles.push_back(vhandle[7]);
+  tmp_face_vhandles.push_back(vhandle[4]);
+  fhandle[5] = mesh.add_face(tmp_face_vhandles);
+
+  // And now delete all faces and vertices
+  // except face (vh[7], vh[6], vh[5], vh[4])
+  // whose handle resides in fhandle[1]
+
+   
+  // Delete face 0
+  mesh.delete_face(fhandle[0], false);
+  // ... face 2
+  mesh.delete_face(fhandle[2], false);
+  // ... face 3
+  mesh.delete_face(fhandle[3], false);
+  // ... face 4
+  mesh.delete_face(fhandle[4], false);
+  // ... face 5
+  mesh.delete_face(fhandle[5], false);
+  
+
+  // If isolated vertices result in a face deletion
+  // they have to be deleted manually. If you want this
+  // to happen automatically, change the second parameter
+  // to true.
+
+  // Now delete the isolated vertices 0, 1, 2 and 3
+  mesh.delete_vertex(vhandle[0], false);
+  mesh.delete_vertex(vhandle[1], false);
+  mesh.delete_vertex(vhandle[2], false);
+  mesh.delete_vertex(vhandle[3], false);
+
+  // Delete all elements that are marked as deleted
+  // from memory.
+  mesh.garbage_collection();
+
+  // write mesh to output.obj
+  try {
+  	if ( !OpenMesh::IO::write_mesh(mesh, "output.off") ) {
+	  std::cerr << "Cannot write mesh to file 'output.off'" << std::endl;
+  	  return 1;
+        }
+  }
+  catch( std::exception& x )
+  {
+    std::cerr << x.what() << std::endl;
+    return 1;
+  }
+ 
+  return 0;
+}

Doc/tutorial_01.docu

-/** \page tutorial_01 First Steps
+/** \page tutorial_01 First Steps - Building a cude
 
 This small example shows:
 \li How to declare your type \c MyMesh,
@@ -61,4 +61,4 @@ included first.
 
 \include build_cube.cc
 
-**/
\ No newline at end of file
+**/

Doc/tutorial_07b.docu

+/** \page tutorial_07b Deleting geometry elements
+
+This small example shows how to remove faces and vertices from a mesh.
+
+We basically use the geometry created in \ref tutorial_01.
+
+If we want our mesh class to be able to remove vertices, faces or (half-) edges
+we have to extend the default traits for our mesh class.
+Vertices, faces and (half-)edges need the OpenMesh::Attributes::Status attribute
+which is used to hold the flag "deleted" if an element is deleted.
+
+The struct which defines the mesh traits then looks like this:
+
+\dontinclude delete_geometry.cc
+\skipline struct
+\until };
+
+After having created the geometry of the cube one can delete faces and vertices
+by simply calling delete_vertices() (delete_faces() or delete_edges() respectiely).
+
+In this example we delete all faces excpet one and the corresponding vertices.
+The code looks like this
+
+\dontinclude delete_geometry.cc
+\skipline // Delete face 0
+\until mesh.delete_vertex(vhandle[3], false);
+
+Now the deleted faces and vertices are marked as "deleted" internally.
+Call garbage_collection() to definitely remove them from memory.
+
+\dontinclude delete_geometry.cc
+\skipline // Delete all
+\until mesh.garbage_collection();
+
+The full source code of the example:
+
+\include delete_geometry.cc
+
+**/
\ No newline at end of file

Doc/tutorial_main.docu

@@ -35,8 +35,9 @@ repeatedly replacing each vertex' position by the center of gravity
 <li> \ref tutorial_05
 <li> \ref tutorial_06
 <li> \ref tutorial_07
+<li> \ref tutorial_07b
 <li> \ref tutorial_08
 <li> \ref tutorial_09
 </ol>
 
-*/
\ No newline at end of file
+*/