TriangleFEMForceField.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    *
* the Free Software Foundation; either version 2.1 of the License, or (at     *
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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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#ifndef SOFA_COMPONENT_FORCEFIELD_TRIANGLEFEMFORCEFIELD_H
#define SOFA_COMPONENT_FORCEFIELD_TRIANGLEFEMFORCEFIELD_H

#if !defined(__GNUC__) || (__GNUC__ > 3 || (_GNUC__ == 3 && __GNUC_MINOR__ > 3))
#pragma once
#endif

#include <sofa/core/componentmodel/behavior/ForceField.h>
#include <sofa/core/componentmodel/topology/BaseMeshTopology.h>
#include <sofa/defaulttype/Vec.h>
#include <sofa/defaulttype/Mat.h>


// corotational triangle from
// @InProceedings{NPF05,
//   author       = "Nesme, Matthieu and Payan, Yohan and Faure, Fran\c{c}ois",
//   title        = "Efficient, Physically Plausible Finite Elements",
//   booktitle    = "Eurographics (short papers)",
//   month        = "august",
//   year         = "2005",
//   editor       = "J. Dingliana and F. Ganovelli",
//   keywords     = "animation, physical model, elasticity, finite elements",
//   url          = "http://www-evasion.imag.fr/Publications/2005/NPF05"
// }



namespace sofa
{

namespace component
{

namespace forcefield
{

using namespace sofa::defaulttype;


template<class DataTypes>
class TriangleFEMForceField : public core::componentmodel::behavior::ForceField<DataTypes>, public virtual core::objectmodel::BaseObject
{
public:
  typedef core::componentmodel::behavior::ForceField<DataTypes> Inherited;
    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    ;

    typedef sofa::core::componentmodel::topology::BaseMeshTopology::index_type Index;
    typedef sofa::core::componentmodel::topology::BaseMeshTopology::Triangle Element;
    typedef sofa::core::componentmodel::topology::BaseMeshTopology::SeqTriangles VecElement;

    static const int SMALL = 1;                                     
    static const int LARGE = 0;                                     

protected:
//    component::MechanicalObject<DataTypes>* _object;

    typedef Vec<6, Real> Displacement;                              

    typedef Mat<3, 3, Real> MaterialStiffness;                      
    typedef sofa::helper::vector<MaterialStiffness> VecMaterialStiffness;    
    VecMaterialStiffness _materialsStiffnesses;                     

    typedef Mat<6, 3, Real> StrainDisplacement;                     
    typedef sofa::helper::vector<StrainDisplacement> VecStrainDisplacement; 
    VecStrainDisplacement _strainDisplacements;                     

    typedef Mat<3, 3, Real > Transformation;                        


    sofa::core::componentmodel::topology::BaseMeshTopology* _mesh;
    const VecElement *_indexedElements;
    Data< VecCoord > _initialPoints; 
//     int _method; ///< the computation method of the displacements
//     Real _poissonRatio;
//     Real _youngModulus;
//     Real _dampingRatio;

public:

    TriangleFEMForceField();

    //virtual const char* getTypeName() const { return "TriangleFEMForceField"; }

    virtual ~TriangleFEMForceField();


    virtual void init();
    virtual void reinit();
    virtual void addForce (VecDeriv& f, const VecCoord& x, const VecDeriv& v);
    
    virtual void addDForce (VecDeriv& df, const VecDeriv& dx);
        
    virtual double getPotentialEnergy(const VecCoord& x);


    void draw();

    int method;
    Data<std::string> f_method;
    Data<Real> f_poisson;
    Data<Real> f_young;
    Data<Real> f_damping;

    Real getPoisson() { return f_poisson.getValue(); }
    void setPoisson(Real val) { f_poisson.setValue(val); }
    Real getYoung() { return f_young.getValue(); }
    void setYoung(Real val) { f_young.setValue(val); }
    Real getDamping() { return f_damping.getValue(); }
    void setDamping(Real val) { f_damping.setValue(val); }
    int  getMethod() { return method; }
    void setMethod(int val) { method = val; }

//     component::MechanicalObject<DataTypes>* getObject()
//     {
//         return _object;
//     }

protected :

    virtual void applyStiffness( VecCoord& f, Real h, const VecCoord& x );
    void computeStrainDisplacement( StrainDisplacement &J, Coord a, Coord b, Coord c);
    void computeMaterialStiffnesses();
    void computeForce( Displacement &F, const Displacement &Depl, const MaterialStiffness &K, const StrainDisplacement &J );

    void initSmall();
    void accumulateForceSmall( VecCoord& f, const VecCoord & p, Index elementIndex, bool implicit = false );
    void accumulateDampingSmall( VecCoord& f, Index elementIndex );
    void applyStiffnessSmall( VecCoord& f, Real h, const VecCoord& x );

    sofa::helper::vector< helper::fixed_array <Coord, 3> > _rotatedInitialElements;   
    sofa::helper::vector< Transformation > _rotations;
    void initLarge();
    void computeRotationLarge( Transformation &r, const VecCoord &p, const Index &a, const Index &b, const Index &c);
    void accumulateForceLarge( VecCoord& f, const VecCoord & p, Index elementIndex, bool implicit=false );
    void accumulateDampingLarge( VecCoord& f, Index elementIndex );
    void applyStiffnessLarge( VecCoord& f, Real h, const VecCoord& x );
};


} // namespace forcefield

} // namespace component

} // namespace sofa

#endif