Force_Gravity.h

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#ifndef SimTK_SIMBODY_FORCE_GRAVITY_H_
#define SimTK_SIMBODY_FORCE_GRAVITY_H_
/* -------------------------------------------------------------------------- *
 *                      SimTK Core: SimTK Simbody(tm)                         *
 * -------------------------------------------------------------------------- *
 * This is part of the SimTK Core biosimulation toolkit originating from      *
 * Simbios, the NIH National Center for Physics-Based Simulation of           *
 * Biological Structures at Stanford, funded under the NIH Roadmap for        *
 * Medical Research, grant U54 GM072970. See https://simtk.org.               *
 *                                                                            *
 * Portions copyright (c) 2010 Stanford University and the Authors.           *
 * Authors: Michael Sherman                                                   *
 * Contributors:                                                              *
 *                                                                            *
 * Permission is hereby granted, free of charge, to any person obtaining a    *
 * copy of this software and associated documentation files (the "Software"), *
 * to deal in the Software without restriction, including without limitation  *
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,   *
 * and/or sell copies of the Software, and to permit persons to whom the      *
 * Software is furnished to do so, subject to the following conditions:       *
 *                                                                            *
 * The above copyright notice and this permission notice shall be included in *
 * all copies or substantial portions of the Software.                        *
 *                                                                            *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR *
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,   *
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL    *
 * THE AUTHORS, CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,    *
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR      *
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE  *
 * USE OR OTHER DEALINGS IN THE SOFTWARE.                                     *
 * -------------------------------------------------------------------------- */

#include "SimTKcommon.h"
#include "simbody/internal/Force.h"

namespace SimTK {

class SimTK_SIMBODY_EXPORT Force::Gravity : public Force {
public:


//------------------------------------------------------------------------------

Gravity(GeneralForceSubsystem&          forces, 
        const SimbodyMatterSubsystem&   matter,
        const Vec3&                     gravity);

Gravity(GeneralForceSubsystem&          forces, 
        const SimbodyMatterSubsystem&   matter,
        const UnitVec3&                 down,
        Real                            g,
        Real                            zeroHeight = 0);

Gravity& setDefaultGravityVector(const Vec3& gravity);

Gravity& setDefaultDownDirection(const UnitVec3& down);

Gravity& setDefaultMagnitude(Real g);

Gravity& setDefaultZeroHeight(Real zeroHeight);

Vec3 getDefaultGravityVector() const;
const UnitVec3& getDefaultDownDirection() const;
Real getDefaultMagnitude() const;
Real getDefaultZeroHeight() const;

//------------------------------------------------------------------------------

const Gravity& setGravityVector(State& state, const Vec3& gravity) const;

const Gravity& setDownDirection(State&           state,
                                const UnitVec3&  down) const;
const Gravity& setMagnitude(State& state, Real g) const;
const Gravity& setZeroHeight(State& state, Real hz) const;

Vec3 getGravityVector(const State& state) const;
const UnitVec3& getDownDirection(const State& state) const;
Real getMagnitude(const State& state) const;
Real getZeroHeight(const State& state) const;

//------------------------------------------------------------------------------

Real getPotentialEnergy(const State& state) const;
const SpatialVec& 
    getBodyForce(const State& state, MobilizedBodyIndex mobod) const;

// Particles aren't supported yet so don't show this in Doxygen.
const Vec3& 
    getParticleForce(const State& state, ParticleIndex particle) const;

// Don't show this in Doxygen.
SimTK_INSERT_DERIVED_HANDLE_DECLARATIONS(Gravity, GravityImpl, Force);
};

} // namespace SimTK

#endif // SimTK_SIMBODY_FORCE_GRAVITY_H_