Line data    Source code

       1             : #pragma once
       2             : 
       3             : #include "elsaDefines.h"
       4             : #include "BoundingBox.h"
       5             : 
       6             : #include "spdlog/fmt/fmt.h"
       7             : 
       8             : #include <Eigen/Geometry>
       9             : #include <limits>
      10             : #include <optional>
      11             : #include <functional>
      12             : 
      13             : namespace elsa
      14             : {
      15             :     /**
      16             :      * @brief min helper function which behaves like the IEEE standard suggests
      17             :      *
      18             :      * @param[in] x first value to find minimum of
      19             :      * @param[in] y second value to find minimum of
      20             :      * @returns the smaller value of x and y
      21             :      *
      22             :      * This function is used, because it tries to suppress NaN's. This behavior is
      23             :      * crucial for edge cases of the intersection algorithm. std::min(x,y) does
      24             :      * not provide this security and should be avoided in this case
      25             :      */
      26             :     template <typename T1, typename T2>
      27             :     constexpr T1 minNum(T1 x, T2 y)
      28      260864 :     {
      29      260864 :         return std::not_equal_to<>()(y, y) ? x : (std::less<>()(x, y) ? x : y);
      30      260864 :     }
      31             : 
      32             :     /**
      33             :      * @brief max helper function which behaves like the IEEE standard suggests
      34             :      *
      35             :      * @param[in] x first value to find maximum of
      36             :      * @param[in] y second value to find maximum of
      37             :      * @returns the bigger value of x and y
      38             :      *
      39             :      * Same thing for NaN's as for the min function
      40             :      */
      41             :     template <typename T1, typename T2>
      42             :     constexpr T1 maxNum(T1 x, T2 y)
      43      496385 :     {
      44      496385 :         return std::not_equal_to<>()(y, y) ? x : (std::greater<>()(x, y) ? x : y);
      45      496385 :     }
      46             : 
      47             :     /**
      48             :      * @brief Helper struct for results of intersection tests
      49             :      */
      50             :     template <class data_t>
      51             :     struct IntersectionResult {
      52             :         /// the parameters for entry/exit points
      53             :         data_t _tmin, _tmax;
      54             : 
      55             :         /// default constructor
      56             :         IntersectionResult()
      57             :             : _tmin{std::numeric_limits<data_t>::infinity()},
      58             :               _tmax{std::numeric_limits<data_t>::infinity()}
      59           0 :         {
      60           0 :         }
      61             : 
      62             :         /// simple constructor with values tmin, tmax
      63      225770 :         IntersectionResult(data_t tmin, data_t tmax) : _tmin{tmin}, _tmax{tmax} {}
      64             :     };
      65             : 
      66             :     namespace detail
      67             :     {
      68             :         template <class data_t, int Dim>
      69             :         std::tuple<data_t, data_t, data_t, data_t>
      70             :             intersect(const BoundingBox& aabb, const Eigen::ParametrizedLine<data_t, Dim>& r);
      71             :     } // namespace detail
      72             : 
      73             :     /**
      74             :      * @brief Compute entry and exit point of ray in a volume (given as an AABB)
      75             :      *
      76             :      * If the ray is running along a border of the bounding box, the lower bound will
      77             :      * be counted as in the bounding and the upper bound will be  counted as outside.
      78             :      *
      79             :      * Method adapted from
      80             :      * https://tavianator.com/fast-branchless-raybounding-box-intersections-part-2-nans/
      81             :      *
      82             :      * @param[in] aabb the volume specified through an axis-aligned bounding box
      83             :      * @param[in] r the ray which we test for intersection with aabb
      84             :      *
      85             :      * @returns nullopt if the volume is not hit, otherwise IntersectionResult
      86             :      *          with entry/exit parameters tmin/tmax
      87             :      */
      88             :     template <class data_t, int Dim>
      89             :     std::optional<IntersectionResult<data_t>>
      90             :         intersectRay(const BoundingBox& aabb, const Eigen::ParametrizedLine<data_t, Dim>& r);
      91             : 
      92             :     /**
      93             :      * @brief Compute the intersection of a ray with the nearest x-plane
      94             :      *
      95             :      * @param[in] aabb the volume specified through an axis-aligned bounding box
      96             :      * @param[in] r the ray which we test for intersection with aabb
      97             :      *
      98             :      * @returns nullopt if the volume is not hit, otherwise IntersectionResult
      99             :      *          with entry/exit parameters tmin/tmax
     100             :      */
     101             :     template <class data_t, int Dim>
     102             :     std::optional<IntersectionResult<data_t>>
     103             :         intersectXPlanes(BoundingBox aabb, const Eigen::ParametrizedLine<data_t, Dim>& r);
     104             : } // namespace elsa
     105             : 
     106             : template <class data_t>
     107             : struct fmt::formatter<elsa::IntersectionResult<data_t>> {
     108             :     template <typename ParseContext>
     109             :     constexpr auto parse(ParseContext& ctx)
     110           0 :     {
     111           0 :         return ctx.begin();
     112           0 :     }
     113             : 
     114             :     template <typename FormatContext>
     115             :     auto format(const elsa::IntersectionResult<data_t>& hit, FormatContext& ctx)
     116           0 :     {
     117           0 :         return fmt::format_to(ctx.out(), "{{ tmin: {}, tmax: {} }}", hit._tmin, hit._tmax);
     118           0 :     }
     119             : };