EBGeometry::RayForm< S, class > Struct Template Reference

How to ray trace a shape directly, instead of marching its signed distance. More...

#include <EBGeometry_Ray.hpp>

Detailed Description

template<class S, class = void>
struct EBGeometry::RayForm< S, class >

How to ray trace a shape directly, instead of marching its signed distance.

The primary template is empty: a shape has no ray form, and the queries march it. A specialisation for a shape type S gives it one, through the functions it defines; they are found by their signatures, so one with a wrong signature is not used (static_assert(hasRayForm<S, T>) checks it):

template <class T>
struct EBGeometry::RayForm<MyShape<T>>
{
  EBGEOMETRY_HOST_DEVICE static HitT<T>
  firstHit(const MyShape<T>& a_shape, const RayT<T>& a_ray, T a_tMin, T a_tMax, const RayOptions<T>& a_options) noexcept;
 
  EBGEOMETRY_HOST_DEVICE static void
  spans(const MyShape<T>& a_shape, const RayT<T>& a_ray, T a_tMin, T a_tMax, const RayOptions<T>& a_options,
        bool a_firstOnly, RaySpansT<T>& a_spans) noexcept;
};

firstHit() makes the shape a ray form: it returns the first crossing in [a_tMin, a_tMax], entering or leaving, with every field of HitT filled in. The others are optional. spans() writes where the ray is inside the object over [a_tMin, a_tMax] (see RaySpansT), which is what an intersection, difference or complement of the shape with others needs to be traced exactly (the ends carry no normal: the composition calls firstHit() near the crossing it ends at for that); a_firstOnly says that only the first crossing is needed (the list may then stop after it, its horizon there). Without spans(), a composition finds the spans by calling firstHit() from one crossing to the next. intersects(), with firstHit()'s arguments and returning HitStatus, is a yes/no query that can stop at the first crossing it finds; without it, intersects() calls firstHit(). The second template parameter is for partial specialisations that depend on a condition.

Template Parameters

S	Shape type.

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The documentation for this struct was generated from the following file:

• Source/EBGeometry_Ray.hpp