polyhedron_volume.hh

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/*
 * Copyright (C) 2019 Open Source Robotics Foundation
 *
 * 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.
 *
*/

#pragma once

#include <cassert>
#include <vector>
#include <gazebo/common/common.hh>
#include <ignition/math/Vector3.hh>
#include <ignition/math/Quaternion.hh>

namespace buoyancy
{
  struct Plane
  {
    Plane();

    ignition::math::Vector3d normal;

    float offset;
  };

  struct Volume
  {
    Volume();

    Volume& operator+=(const Volume& rhs);

    double volume;

    ignition::math::Vector3d centroid;
  };

  class Polyhedron
  {
    public: struct Face
    {
      Face() = default;

      Face(int i1, int i2, int i3);

      int i1, i2, i3;
    };

    public: static Polyhedron makeCube(double x,
                                       double y,
                                       double z);

    public: static Polyhedron makeCylinder(double r,
                                           double l,
                                           int n);

    public: Volume ComputeFullVolume();

    public: Volume SubmergedVolume(const ignition::math::Vector3d &x,
                                   const ignition::math::Quaterniond &q,
                                   Plane &plane);

    private: static Volume tetrahedronVolume(const ignition::math::Vector3d& v1,
                                             const ignition::math::Vector3d& v2,
                                             const ignition::math::Vector3d& v3,
                                             const ignition::math::Vector3d& p =
                                        ignition::math::Vector3d({0., 0., 0.}));

    private: static Volume clipTriangle(const ignition::math::Vector3d& v1,
                                        const ignition::math::Vector3d& v2,
                                        const ignition::math::Vector3d& v3,
                                        double d1,
                                        double d2,
                                        double d3,
                                        const ignition::math::Vector3d& p =
                                      ignition::math::Vector3d({0., 0., 0.}));

    private: std::vector<ignition::math::Vector3d> vertices;

    private: std::vector<Face> faces;

    private: const double EPSILON = 1e-6;
  };  // class Polyhedron
}