text: // ----------------------------------------------------------------------------
  // -                        Open3D: www.open3d.org                            -
  // ----------------------------------------------------------------------------
  // The MIT License (MIT)
  //
  // Copyright (c) 2018 www.open3d.org
  //
  // 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 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.
  // ----------------------------------------------------------------------------
  
  #pragma once
  
  #include <vector>
  #include <memory>
  #include <Eigen/Core>
  #include <Open3D/Geometry/Geometry3D.h>
  
  namespace open3d {
  namespace geometry {
  
  class PointCloud;
  class TriangleMesh;
  
  class VoxelGrid : public Geometry3D {
  public:
      VoxelGrid() : Geometry3D(Geometry::GeometryType::VoxelGrid){};
      ~VoxelGrid() override{};
  
  public:
      void Clear() override;
      bool IsEmpty() const override;
      Eigen::Vector3d GetMinBound() const override;
      Eigen::Vector3d GetMaxBound() const override;
      void Transform(const Eigen::Matrix4d &transformation) override;
  
  public:
      VoxelGrid &operator+=(const VoxelGrid &voxelgrid);
      VoxelGrid operator+(const VoxelGrid &voxelgrid) const;
  
  public:
      bool HasVoxels() const { return voxels_.size() > 0; }
  
      bool HasColors() const {
          return voxels_.size() > 0 && colors_.size() == voxels_.size();
      }
  
  public:
      double voxel_size_;
      Eigen::Vector3d origin_;
      std::vector<Eigen::Vector3i> voxels_;
      std::vector<Eigen::Vector3d> colors_;
  };
  
  std::shared_ptr<VoxelGrid> CreateSurfaceVoxelGridFromPointCloud(
          const PointCloud &input, double voxel_size);
  
  }  // namespace geometry
  }  // namespace open3d
  