/*=========================================================================

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: MeshKComplex.cxx,v $
  Language:  C++
  Date:      $Date: 2003/09/10 14:29:51 $
  Version:   $Revision: 1.15 $

  Copyright (c) Insight Software Consortium. All rights reserved.
  See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even 
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/

//  Software Guide : BeginLatex
//
//  The \doxygen{Mesh} class supports the representation of formal
//  topologies. In particular the concept of \emph{K-Complex} can be
//  correctly represented in the Mesh. An informal definition of K-Complex
//  may be as follows: a K-Complex is a topological structure in which for
//  every cell of dimension $N$, its boundary faces which are cells of
//  dimension $N-1$ also belong to the structure.
//
//  This section illustrates how to instantiate a K-Complex structure using the
//  mesh. The example structure is composed of one tetrahedron, its
//  four triangle faces, its six line edges and its four vertices.
//
//  \index{itk::Mesh!K-Complex}
//
//  Software Guide : EndLatex 


//  Software Guide : BeginLatex
//
//  The header files of all the cell types involved should be loaded along with
//  the header file of the mesh class.
//
//  \index{itk::LineCell!header}
//  \index{itk::VertexCell!header}
//  \index{itk::TriangleCell!header}
//  \index{itk::TetrahedronCell!header}
//
//  Software Guide : EndLatex 


// Software Guide : BeginCodeSnippet
#include "itkMesh.h"
#include "itkVertexCell.h"
#include "itkLineCell.h"
#include "itkTriangleCell.h"
#include "itkTetrahedronCell.h"
// Software Guide : EndCodeSnippet


int main()
{
  //  Software Guide : BeginLatex
  //  
  //  Then the PixelType is defined and the mesh type is instantiated with it.
  //  Note that the dimension of the space is three in this case.
  //
  //  \index{itk::Mesh!Instantiation}
  //  \index{itk::Mesh!PixelType}
  //
  //  Software Guide : EndLatex 

  // Software Guide : BeginCodeSnippet
  typedef float                             PixelType;
  typedef itk::Mesh< PixelType, 3 >         MeshType;
  // Software Guide : EndCodeSnippet


  //  Software Guide : BeginLatex
  //
  //  The cell type can now be instantiated using the traits
  //  taken from the Mesh.  
  //
  //  \index{itk::LineCell!Instantiation}
  //  \index{itk::VertexCell!Instantiation}
  //  \index{itk::TriangleCell!Instantiation}
  //  \index{itk::TetrahedronCell!Instantiation}
  //
  //  Software Guide : EndLatex 

  // Software Guide : BeginCodeSnippet
  typedef MeshType::CellType                CellType;
  typedef itk::VertexCell< CellType >       VertexType;
  typedef itk::LineCell< CellType >         LineType;
  typedef itk::TriangleCell< CellType >     TriangleType;
  typedef itk::TetrahedronCell< CellType >  TetrahedronType;
  // Software Guide : EndCodeSnippet


  //  Software Guide : BeginLatex
  //
  //  The mesh is created and the points associated with the vertices are
  //  inserted.  Note that there is an important distinction between the
  //  points in the mesh and the \doxygen{VertexCell} concept. A VertexCell
  //  is a cell of dimension zero. Its main difference as compared to a point
  //  is that the cell can be aware of neighborhood relationships with other
  //  cells. Points are not aware of the existence of cells. In fact, from
  //  the pure topological point of view, the coordinates of points in the
  //  mesh are completely irrelevant.  They may as well be absent from the
  //  mesh structure altogether.  VertexCells on the other hand are necessary
  //  to represent the full set of neighborhood relationships on the
  //  K-Complex.
  //
  //  The geometrical coordinates of the nodes of a regular tetrahedron can be
  //  obtained by taking every other node from a regular cube.
  //
  //  \index{itk::Mesh!New()}
  //  \index{itk::Mesh!SetPoint()}
  //  \index{itk::Mesh!PointType}
  //  \index{itk::Mesh!Pointer}
  //
  //  Software Guide : EndLatex 

  // Software Guide : BeginCodeSnippet
  MeshType::Pointer  mesh = MeshType::New();

  MeshType::PointType   point0;
  MeshType::PointType   point1;
  MeshType::PointType   point2;
  MeshType::PointType   point3;

  point0[0] = -1; point0[1] = -1; point0[2] = -1; 
  point1[0] =  1; point1[1] =  1; point1[2] = -1; 
  point2[0] =  1; point2[1] = -1; point2[2] =  1; 
  point3[0] = -1; point3[1] =  1; point3[2] =  1; 

  mesh->SetPoint( 0, point0 );
  mesh->SetPoint( 1, point1 );
  mesh->SetPoint( 2, point2 );
  mesh->SetPoint( 3, point3 );
  // Software Guide : EndCodeSnippet


  //  Software Guide : BeginLatex
  //
  //  We proceed now to create the cells, associate them with the points and
  //  insert them on the mesh. Starting with the tetrahedron we write the
  //  following code.
  //
  //  \index{itk::AutoPointer!TakeOwnership()}
  //  \index{CellAutoPointer!TakeOwnership()}
  //  \index{CellType!creation}
  //  \index{itk::Mesh!SetCell()}
  //  \index{itk::TetrahedronCell!Instantiation}
  //  \index{itk::TetrahedronCell!SetPointId()}
  //
  //  Software Guide : EndLatex 


  // Software Guide : BeginCodeSnippet
  CellType::CellAutoPointer cellpointer;

  cellpointer.TakeOwnership( new TetrahedronType );
  cellpointer->SetPointId( 0, 0 );
  cellpointer->SetPointId( 1, 1 );
  cellpointer->SetPointId( 2, 2 );
  cellpointer->SetPointId( 3, 3 );
  mesh->SetCell( 0, cellpointer );
  // Software Guide : EndCodeSnippet

  //  Software Guide : BeginLatex
  //  
  //  Four triangular faces are created and associated with the mesh now.
  //  The first triangle connects points {0,1,2}.
  //
  //  \index{itk::TriangleCell!Instantiation}
  //  \index{itk::TriangleCell!SetPointId()}
  //
  //  Software Guide : EndLatex 


  // Software Guide : BeginCodeSnippet
  cellpointer.TakeOwnership( new TriangleType );
  cellpointer->SetPointId( 0, 0 );
  cellpointer->SetPointId( 1, 1 );
  cellpointer->SetPointId( 2, 2 );
  mesh->SetCell( 1, cellpointer );
  // Software Guide : EndCodeSnippet


  //  Software Guide : BeginLatex
  //  
  //  The second triangle connects points { 0, 2, 3 }
  //
  //  Software Guide : EndLatex 

  // Software Guide : BeginCodeSnippet
  cellpointer.TakeOwnership( new TriangleType );
  cellpointer->SetPointId( 0, 0 );
  cellpointer->SetPointId( 1, 2 );
  cellpointer->SetPointId( 2, 3 );
  mesh->SetCell( 2, cellpointer );
  // Software Guide : EndCodeSnippet
    

  //  Software Guide : BeginLatex
  //  
  //  The third triangle connects points { 0, 3, 1 }
  //
  //  Software Guide : EndLatex 

   // Software Guide : BeginCodeSnippet
  cellpointer.TakeOwnership( new TriangleType );
  cellpointer->SetPointId( 0, 0 );
  cellpointer->SetPointId( 1, 3 );
  cellpointer->SetPointId( 2, 1 );
  mesh->SetCell( 3, cellpointer );
  // Software Guide : EndCodeSnippet


  //  Software Guide : BeginLatex
  //  
  //  The fourth triangle connects points { 3, 2, 1 }
  //
  //  Software Guide : EndLatex 

  // Software Guide : BeginCodeSnippet
  cellpointer.TakeOwnership( new TriangleType );
  cellpointer->SetPointId( 0, 3 );
  cellpointer->SetPointId( 1, 2 );
  cellpointer->SetPointId( 2, 1 );
  mesh->SetCell( 4, cellpointer );
  // Software Guide : EndCodeSnippet

  //  Software Guide : BeginLatex
  //  
  //  Note how the \code{CellAutoPointer} is reused every time. Reminder: the
  //  \doxygen{AutoPointer} loses ownership of the cell when it is passed as
  //  an argument of the \code{SetCell()} method. The AutoPointer is attached
  //  to a new cell by using the \code{TakeOwnership()} method.
  //
  //  The construction of the K-Complex continues now with the creation of the
  //  six lines on the tetrahedron edges.
  //
  //  \index{itk::LineCell!Instantiation}
  //  \index{itk::LineCell!SetPointId()}
  //
  //  Software Guide : EndLatex 

  // Software Guide : BeginCodeSnippet
  cellpointer.TakeOwnership( new LineType );
  cellpointer->SetPointId( 0, 0 );
  cellpointer->SetPointId( 1, 1 );
  mesh->SetCell( 5, cellpointer );

  cellpointer.TakeOwnership( new LineType );
  cellpointer->SetPointId( 0, 1 );
  cellpointer->SetPointId( 1, 2 );
  mesh->SetCell( 6, cellpointer );

  cellpointer.TakeOwnership( new LineType );
  cellpointer->SetPointId( 0, 2 );
  cellpointer->SetPointId( 1, 0 );
  mesh->SetCell( 7, cellpointer );

  cellpointer.TakeOwnership( new LineType );
  cellpointer->SetPointId( 0, 1 );
  cellpointer->SetPointId( 1, 3 );
  mesh->SetCell( 8, cellpointer );

  cellpointer.TakeOwnership( new LineType );
  cellpointer->SetPointId( 0, 3 );
  cellpointer->SetPointId( 1, 2 );
  mesh->SetCell( 9, cellpointer );

  cellpointer.TakeOwnership( new LineType );
  cellpointer->SetPointId( 0, 3 );
  cellpointer->SetPointId( 1, 0 );
  mesh->SetCell( 10, cellpointer );
  // Software Guide : EndCodeSnippet


  //  Software Guide : BeginLatex
  //  
  //  Finally the zero dimensional cells represented by the
  //  \doxygen{VertexCell} are created and inserted in the mesh.
  //
  //  Software Guide : EndLatex 

  // Software Guide : BeginCodeSnippet
  cellpointer.TakeOwnership( new VertexType );
  cellpointer->SetPointId( 0, 0 );
  mesh->SetCell( 11, cellpointer );

  cellpointer.TakeOwnership( new VertexType );
  cellpointer->SetPointId( 0, 1 );
  mesh->SetCell( 12, cellpointer );

  cellpointer.TakeOwnership( new VertexType );
  cellpointer->SetPointId( 0, 2 );
  mesh->SetCell( 13, cellpointer );

  cellpointer.TakeOwnership( new VertexType );
  cellpointer->SetPointId( 0, 3 );
  mesh->SetCell( 14, cellpointer );
  // Software Guide : EndCodeSnippet


  // Print out the number of points and the number of cells.
  std::cout << "# Points= " << mesh->GetNumberOfPoints() << std::endl;
  std::cout << "# Cell  = " << mesh->GetNumberOfCells() << std::endl;


  //  Software Guide : BeginLatex
  //
  //  At this point the Mesh contains four points and fourteen cells.  The
  //  points can be visited using PointContainer iterators 
  //
  // \index{itk::Mesh!PointsContainer}
  // \index{itk::Mesh!PointsIterators}
  // \index{itk::Mesh!GetPoints()}
  // \index{PointsContainer!Begin()}
  // \index{PointsContainer!End()}
  //
  //  Software Guide : EndLatex 

  // Software Guide : BeginCodeSnippet
  typedef MeshType::PointsContainer::ConstIterator  PointIterator;
  PointIterator pointIterator = mesh->GetPoints()->Begin();
  PointIterator pointEnd      = mesh->GetPoints()->End();
  
  while( pointIterator != pointEnd )