LinearSpring.h

// This file is a part of the OpenSurgSim project.
// Copyright 2013, SimQuest Solutions Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef SURGSIM_PHYSICS_LINEARSPRING_H
#define SURGSIM_PHYSICS_LINEARSPRING_H

#include "SurgSim/Physics/Spring.h"

namespace SurgSim
{
namespace Math
{
class OdeState;
}
namespace Physics
{
class MassSpringModel;

class LinearSpring : public Spring
{
public:
    LinearSpring(size_t nodeId0, size_t nodeId1);

    explicit LinearSpring(const std::shared_ptr<Math::OdeState> state, size_t nodeId0, size_t nodeId1, double stiffness,
        double damping);

    explicit LinearSpring(const std::shared_ptr<MassSpringModel> massSpring, size_t nodeId0, size_t nodeId1,
        double stiffness, double damping);

    void initialize(const SurgSim::Math::OdeState& state) override;

    void setStiffness(double stiffness);

    double getStiffness() const;

    void setDamping(double damping);

    double getDamping() const;

    void setRestLength(double restLength);

    double getRestLength() const;

    void addForce(const SurgSim::Math::OdeState& state, SurgSim::Math::Vector* F, double scale = 1.0) override;

    void addDamping(const SurgSim::Math::OdeState& state, SurgSim::Math::SparseMatrix* D, double scale = 1.0) override;

    void addStiffness(const SurgSim::Math::OdeState& state, SurgSim::Math::SparseMatrix* K,
                      double scale = 1.0) override;

    void addFDK(const SurgSim::Math::OdeState& state, SurgSim::Math::Vector* F,
                SurgSim::Math::SparseMatrix* D, SurgSim::Math::SparseMatrix* K) override;

    void addMatVec(const SurgSim::Math::OdeState& state, double alphaD, double alphaK,
                   const SurgSim::Math::Vector& vector, SurgSim::Math::Vector* F) override;

    bool operator ==(const Spring& spring) const;

    bool operator !=(const Spring& spring) const;

protected:
    bool computeDampingAndStiffness(const SurgSim::Math::OdeState& state,
                                    SurgSim::Math::Matrix33d* De,
                                    SurgSim::Math::Matrix33d* Ke);

private:
    double m_restLength;

    double m_stiffness;

    double m_damping;
};

}; // namespace Physics

}; // namespace SurgSim

#endif // SURGSIM_PHYSICS_LINEARSPRING_H