polygon.h

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/* Author: Zachary Kingston */

#ifndef SE2EZ_CORE_CGAL_POLYGON_
#define SE2EZ_CORE_CGAL_POLYGON_

#include <Eigen/Core>
#include <Eigen/Geometry>

#include <se2ez/core/class_forward.h>
#include <se2ez/core/math.h>

namespace se2ez
{
    /** \cond IGNORE */
    SE2EZ_CLASS_FORWARD(Geometry)
    /** \endcond */

    /** \brief Operations on geometry.
     */
    namespace geo
    {
        /** \brief Checks if a polygon is convex.
         *  \param[in] geometry Geometry to check (must be a polygon)
         *  \return Returns true if the polygon is convex, false otherwise.
         */
        bool isConvex(const Geometry &geometry);

        /** \brief Checks if a polygon is simple, that is, it has no holes.
         *  \param[in] geometry Geometry to check (must be a polygon)
         *  \return Returns true if the polygon is simple.
         */
        bool isSimple(const Geometry &geometry);

        /** \brief If not clockwise, reorders polygon vertices to be in clockwise orientation.
         *  \param[in,out] geometry Geometry to reorder.
         */
        void makeClockwise(Geometry &geometry);

        /** \brief If not counterclockwise, reorders polygon vertices to be in counterclockwise orientation.
         *  \param[in,out] geometry Geometry to reorder.
         */
        void makeCounterClockwise(Geometry &geometry);

        /** \brief Compute the area of a polygon.
         *  \param[in] geometry Geometry to compute area for.
         *  \return The signed area of the polygon (negative if clockwise, positive if counter).
         */
        double area(const Geometry &geometry);

        /** \brief Performs an approximate convex decomposition on the geometry.
         *  \param[in] geometry Geometry to decompose.
         *  \return A vector of the convex partitions of the original geometry.
         */
        std::vector<GeometryPtr> convexifyApproximate(const GeometryPtr &geometry);

        /** \brief Performs an optimal convex decomposition on the geometry.
         *  \param[in] geometry Geometry to decompose.
         *  \return A vector of the convex partitions of the original geometry.
         */
        std::vector<GeometryPtr> convexifyOptimal(const GeometryPtr &geometry);

        /** \brief "Shatters" a convex polygon into a fan of triangles using the first point as the root for
         all triangles.
         *  \param[in] geometry Geometry to shatter.
         *  \return A vector of triangle polygons from the original geometry.
         */
        std::vector<GeometryPtr> shatter(const GeometryPtr &geometry);
    }  // namespace geo
}  // namespace se2ez

#endif