height_map.h

Go to the documentation of this file.

/******************************************************************************
Copyright (c) 2018, Alexander W. Winkler. All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.

* Neither the name of the copyright holder nor the names of its
  contributors may be used to endorse or promote products derived from
  this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
******************************************************************************/

#ifndef TOWR_HEIGHT_MAP_H_
#define TOWR_HEIGHT_MAP_H_

#include <memory>
#include <vector>
#include <Eigen/Dense>

#include "variables/cartesian_dimensions.h"

namespace towr {

class HeightMap {
public:
  using Ptr      = std::shared_ptr<HeightMap>;
  using Vector3d = Eigen::Vector3d;

  enum Direction { Normal, Tangent1, Tangent2 };

  HeightMap() = default;
  virtual ~HeightMap () = default;

  virtual double GetHeight(double x, double y) const = 0;

  double GetDerivativeOfHeightWrt(Dim2D dim, double x, double y) const;

  Vector3d GetNormalizedBasis(Direction direction, double x, double y) const;

  Vector3d GetDerivativeOfNormalizedBasisWrt(Direction direction, Dim2D dim,
                                             double x, double y) const;
  double GetFrictionCoeff() const { return friction_coeff_; };

protected:
  double friction_coeff_ = 0.5;

private:
  using DimDerivs = std::vector<Dim2D>; 

  Vector3d GetBasis(Direction direction, double x, double y,
                    const DimDerivs& dim_deriv= {}) const;

  Vector3d GetNormal(double x,   double y, const DimDerivs& = {}) const;
  Vector3d GetTangent1(double x, double y, const DimDerivs& = {}) const;
  Vector3d GetTangent2(double x, double y, const DimDerivs& = {}) const;

  double GetSecondDerivativeOfHeightWrt(Dim2D dim1, Dim2D dim2,
                                        double x, double y) const;

  Vector3d GetDerivativeOfNormalizedVectorWrtNonNormalizedIndex(
      const Vector3d& non_normalized, int index) const;

  // first derivatives that must be implemented by the user
  virtual double GetHeightDerivWrtX(double x, double y) const { return 0.0; };
  virtual double GetHeightDerivWrtY(double x, double y) const { return 0.0; };

  // second derivatives with respect to first letter, then second
  virtual double GetHeightDerivWrtXX(double x, double y) const { return 0.0; };
  virtual double GetHeightDerivWrtXY(double x, double y) const { return 0.0; };
  virtual double GetHeightDerivWrtYX(double x, double y) const { return 0.0; };
  virtual double GetHeightDerivWrtYY(double x, double y) const { return 0.0; };
};

} /* namespace towr */

#endif /* TOWR_HEIGHT_MAP_H_ */