TensorForceField.h

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/******************************************************************************
*       SOFA, Simulation Open-Framework Architecture, version 1.0 beta 3      *
*                (c) 2006-2008 MGH, INRIA, USTL, UJF, CNRS                    *
*                                                                             *
* 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    *
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* your option) any later version.                                             *
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License *
* for more details.                                                           *
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* You should have received a copy of the GNU Lesser General Public License    *
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA.          *
*******************************************************************************
*                               SOFA :: Modules                               *
*                                                                             *
* Authors: The SOFA Team and external contributors (see Authors.txt)          *
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* Contact information: contact@sofa-framework.org                             *
******************************************************************************/
#ifndef SOFA_COMPONENT_FORCEFIELD_TENSORFORCEFIELD_H
#define SOFA_COMPONENT_FORCEFIELD_TENSORFORCEFIELD_H


#include <sofa/core/componentmodel/behavior/ForceField.h>
#include <sofa/component/MechanicalObject.h>


namespace sofa
{

namespace component
{

namespace forcefield
{

template <class DataTypes>
class TensorForceField : public core::componentmodel::behavior::BaseForceField
{
public:

  TensorForceField (const char *filename);

    
  TensorForceField (component::MechanicalObject<DataTypes>* object,
                        const char* filename);

   
  virtual void addForce ();

  
  virtual void addDForce();
  
  virtual double getPotentialEnergy();

  void draw();


public:
  typedef typename DataTypes::VecCoord VecCoord;
  typedef typename DataTypes::VecDeriv VecDeriv;
  typedef typename DataTypes::Coord    Coord   ;
  typedef typename DataTypes::Deriv    Deriv   ;
  typedef typename Coord::value_type   Real    ;
    class VertexTensor {
    public:
      Real tensor[3][3];
        
      void resetToNull() {
          for (int i = 0; i < 3; ++i) {
            for (int j = 0; j < 3; ++j) {
              tensor[i][j] = 0.0;
            }
          }
      }

    }; //class VertexTensor



    class Edge {
    public:
        int index;
      
        int vertex[2];
      
    }; // class Edge



    class EdgeTensor {
    public:
      Real tensor[3][3];
      
      void resetToNull() {
          for (int i = 0; i < 3; ++i) {
            for (int j = 0; j < 3; ++j) {
              tensor[i][j] = 0.0;
            }
          }
      }

    }; // class EdgeTensor



    class Triangle {
    public:
        int index;
      
        int vertex[3];
      
      double shapeVector[3];
      double squareRestArea;
      
    }; // class Triangle



    class Tetrahedron {
    public:
        int index;
      
        int vertex  [4];
        int edge    [6];
        int triangle[4];

      Real triangleShapeVector[4][3];
        Real restVolume;
      
    }; // class Tetrahedron


private: 
    // Mechanical Object containing this Force Field
    component::MechanicalObject<DataTypes>* object_;
    // damping factor
    Real alpha_;
    // Lame coefficient
    Real lambda_, mu_;
    sofa::helper::vector< Coord >    vertex_      ;
    sofa::helper::vector< Edge >         edge_        ;
    sofa::helper::vector< Triangle >     triangle_    ;
    sofa::helper::vector< Tetrahedron >  tetrahedron_ ;
    sofa::helper::vector< VertexTensor > vertexTensor_;
    sofa::helper::vector< EdgeTensor >   edgeTensor_  ;

private:
    // load the topological informations from a file.
    void load(const char *filename);
    
    // initialize the tensors
    void initialize();
    
    // search for the edge connecting the given vertices, create it if not found
    int getEdge(const int v0, const int v1);
    
    // search for the triangle connecting the given vertices, create it if not found
    int getTriangle(const int v0, const int v1, const int v2);
    
    // add the elastic tensors for this tetrahedron
    void addElasticTensors(Tetrahedron& tetra);
    
}; // class TensorForceField



} // namespace forcefield

} // namespace component

} // namespace sofa

#endif /* _TENSORMASSFORCEFIELD_H_ */