imstkPbdBaryPointToPointConstraint.h

/*
** This file is part of the Interactive Medical Simulation Toolkit (iMSTK)
** iMSTK is distributed under the Apache License, Version 2.0.
** See accompanying NOTICE for details.
*/

#pragma once

#include "imstkPbdCollisionConstraint.h"

namespace imstk
{
class PbdBaryPointToPointConstraint : public PbdCollisionConstraint
{
public:
    PbdBaryPointToPointConstraint() : PbdCollisionConstraint(0, 0) { }
    ~PbdBaryPointToPointConstraint() override = default;

    IMSTK_TYPE_NAME(PbdBaryPointToPointConstraint)

    double getRestLength() const { return m_restLength; }
    void setRestLength(const double length) { m_restLength = length; }

    Vec3d computeInterpolantDifference(PbdState& bodies) const;

    void initConstraintToRest(
        PbdState& bodies,
        const std::vector<PbdParticleId>& ptIdsA,
        const std::vector<double>& weightsA,
        const std::vector<PbdParticleId>& ptIdsB,
        const std::vector<double>& weightsB,
        const double stiffnessA, const double stiffnessB);

    void initConstraint(
        const std::vector<PbdParticleId>& ptIdsA,
        const std::vector<double>& weightsA,
        const std::vector<PbdParticleId>& ptIdsB,
        const std::vector<double>& weightsB,
        const double stiffnessA, const double stiffnessB,
        const double restLength = 0.0);

    bool computeValueAndGradient(PbdState& bodies,
                                 double& c, std::vector<Vec3d>& dcdx) override;

    double getRestValue() const { return m_restLength; }

protected:
    double m_restLength = 0.0;
    // Bary weights A and B ordered in sequence
    std::vector<double> m_weights;
};
} // namespace imstk