TriangularQuadraticSpringsForceField.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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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License *
* for more details.                                                           *
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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)          *
*                                                                             *
* Contact information: contact@sofa-framework.org                             *
******************************************************************************/
#ifndef SOFA_COMPONENT_FORCEFIELD_TRIANGULARQUADRATICSPRINGSFORCEFIELD_H
#define SOFA_COMPONENT_FORCEFIELD_TRIANGULARQUADRATICSPRINGSFORCEFIELD_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>
#include <sofa/component/topology/TriangleData.h>
#include <sofa/component/topology/EdgeData.h>


namespace sofa
{

namespace component
{


namespace forcefield
{
using namespace sofa::helper;
using namespace sofa::defaulttype;
using namespace sofa::component::topology;


template<class DataTypes>
class TriangularQuadraticSpringsForceField : 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    ;


    class Mat3 : public fixed_array<Deriv,3>
    {
    public:
        Deriv operator*(const Deriv& v)
        {
            return Deriv((*this)[0]*v,(*this)[1]*v,(*this)[2]*v);
        }
        Deriv transposeMultiply(const Deriv& v) 
        {
            return Deriv(v[0]*((*this)[0])[0]+v[1]*((*this)[1])[0]+v[2]*((*this)[2][0]),
                v[0]*((*this)[0][1])+v[1]*((*this)[1][1])+v[2]*((*this)[2][1]),
                v[0]*((*this)[0][2])+v[1]*((*this)[1][2])+v[2]*((*this)[2][2]));
        }
    };

protected: 


  class EdgeRestInformation
    {
    public:
        Real  restLength;   // the rest length  
        Real  currentLength;    // the current edge length 
        Real  dl;  // the current unit direction
        Real stiffness;
        
        EdgeRestInformation() {
        }
    };

   class TriangleRestInformation
    {
    public:
        Real  gamma[3]; // the angular stiffness 
        Real stiffness[3]; // the elongation stiffness
        Mat3 DfDx[3]; 

        TriangleRestInformation() {
        }
    };
    
    TriangleData<TriangleRestInformation> triangleInfo;
    EdgeData<EdgeRestInformation> edgeInfo;
        
    sofa::core::componentmodel::topology::BaseMeshTopology* _topology;
    Data< VecCoord > _initialPoints;                                        

    bool updateMatrix;

    Data<Real> f_poissonRatio;
    Data<Real> f_youngModulus;
    Data<Real> f_dampingRatio;
    Data<bool> f_useAngularSprings; // whether angular springs should be included

    Real lambda;  
    Real mu;    
public:

    TriangularQuadraticSpringsForceField();

    virtual ~TriangularQuadraticSpringsForceField();

    virtual double getPotentialEnergy(const VecCoord& x);

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

    virtual Real getLambda() const { return lambda;}
    virtual Real getMu() const { return mu;}

    void setYoungModulus(const double modulus) {
        f_youngModulus.setValue((Real)modulus);
    }
    void setPoissonRatio(const double ratio) {
        f_poissonRatio.setValue((Real)ratio);
    }
    void includeAngularSprings(const bool useAngularSprings) {
        f_useAngularSprings.setValue(useAngularSprings);
    }


    // handle topological changes
    virtual void handleTopologyChange();

    void draw();
    void updateLameCoefficients();



protected :

    EdgeData<EdgeRestInformation> &getEdgeInfo() {return edgeInfo;}

    static void TRQSEdgeCreationFunction(int edgeIndex, void* param, EdgeRestInformation &ei,
                                         const Edge& ,  const sofa::helper::vector< unsigned int > &,
                                         const sofa::helper::vector< double >&);
    static void TRQSTriangleCreationFunction (int , void* , 
                            TriangleRestInformation &,
                            const Triangle& , const sofa::helper::vector< unsigned int > &, const sofa::helper::vector< double >&);
                                    

    static void TRQSTriangleDestroyFunction ( int , void* , TriangleRestInformation &);

};
} //namespace forcefield

} // namespace Components


} // namespace Sofa



#endif /* _TriangularQuadraticSpringsForceField_H_ */