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 * $Id$
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#pragma once

#include <pcl/point_types.h>
#include <pcl/surface/processing.h>

namespace pcl
{

  /** \brief The ear clipping triangulation algorithm.
    * The code is inspired by Flavien Brebion implementation, which is
    * in n^3 and does not handle holes.
    * \author Nicolas Burrus
    * \ingroup surface
    */
  class PCL_EXPORTS EarClipping : public MeshProcessing
  {
    public:
      using Ptr = shared_ptr<EarClipping>;
      using ConstPtr = shared_ptr<const EarClipping>;

      using MeshProcessing::input_mesh_;
      using MeshProcessing::initCompute;
      /** \brief Empty constructor */
      EarClipping () = default;

    protected:
      /** \brief a Pointer to the point cloud data. */
      pcl::PointCloud<pcl::PointXYZ>::Ptr points_;

      /** \brief This method should get called before starting the actual computation. */
      bool
      initCompute () override;

      /** \brief The actual surface reconstruction method. 
        * \param[out] output the output polygonal mesh 
        */
      void
      performProcessing (pcl::PolygonMesh &output) override;

      /** \brief Triangulate one polygon. 
        * \param[in] vertices the set of vertices
        * \param[out] output the resultant polygonal mesh
        */
      void
      triangulate (const Vertices& vertices, PolygonMesh& output);

      /** \brief Compute the signed area of a polygon. 
        * \param[in] vertices the vertices representing the polygon 
        */
      float
      area (const Indices& vertices);

      /** \brief Check if the triangle (u,v,w) is an ear. 
        * \param[in] u the first triangle vertex 
        * \param[in] v the second triangle vertex 
        * \param[in] w the third triangle vertex 
        * \param[in] vertices a set of input vertices
        */
      bool
      isEar (int u, int v, int w, const Indices& vertices);

      /** \brief Check if p is inside the triangle (u,v,w). 
        * \param[in] u the first triangle vertex 
        * \param[in] v the second triangle vertex 
        * \param[in] w the third triangle vertex 
        * \param[in] p the point to check
        */
      bool
      isInsideTriangle (const Eigen::Vector3f& u,
                        const Eigen::Vector3f& v,
                        const Eigen::Vector3f& w,
                        const Eigen::Vector3f& p);

      /** \brief Compute the cross product between 2D vectors.
       * \param[in] p1 the first 2D vector
       * \param[in] p2 the first 2D vector
       */
      float
      crossProduct (const Eigen::Vector2f& p1, const Eigen::Vector2f& p2) const
      {
        return p1[0]*p2[1] - p1[1]*p2[0];
      }

  };

}
