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Add n-dim versions of orientation(points) and add orientation(vectors)

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This commit is contained in:
Nikita Lisitsa 2020-09-30 07:22:27 +03:00
parent 767eb786d5
commit 4bb287eb70
2 changed files with 38 additions and 22 deletions
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50
libs/geom/include/psemek/geom/orientation.hpp
View file

@ -14,25 +14,6 @@
namespace psemek::geom namespace psemek::geom
{ {
// TODO: generic implementation
template <typename T>
#ifdef PSEMEK_GEOM_ROBUST_PREDICATES
std::enable_if_t<!std::is_floating_point_v<T>, sign_t>
#else
sign_t
#endif
orientation(point<T, 2> const & p0, point<T, 2> const & p1, point<T, 2> const & p2)
{
T const d = det(p1 - p0, p2 - p0);
if (d > T{})
return sign_t::positive;
else if (d < T{})
return sign_t::negative;
else
return sign_t::zero;
}
#ifdef PSEMEK_GEOM_ROBUST_PREDICATES #ifdef PSEMEK_GEOM_ROBUST_PREDICATES
template <typename T> template <typename T>
std::enable_if_t<std::is_floating_point_v<T>, sign_t> std::enable_if_t<std::is_floating_point_v<T>, sign_t>
@ -59,10 +40,15 @@ namespace psemek::geom
} }
#endif #endif
template <typename T> template <typename T, std::size_t N, typename ... Vectors>
sign_t orientation(point<T, 3> const & p0, point<T, 3> const & p1, point<T, 3> const & p2, point<T, 3> const & p3) #ifdef PSEMEK_GEOM_ROBUST_PREDICATES
std::enable_if_t<!std::is_floating_point_v<T>, sign_t>
#else
sign_t
#endif
orientation(vector<T, N> const & v1, Vectors const & ... vs)
{ {
T const d = det(p0 - p3, p1 - p3, p2 - p3); T const d = det(v1, vs...);
if (d > T{}) if (d > T{})
return sign_t::positive; return sign_t::positive;
@ -72,4 +58,24 @@ namespace psemek::geom
return sign_t::zero; return sign_t::zero;
} }
template <typename T, std::size_t N, typename ... Points>
#ifdef PSEMEK_GEOM_ROBUST_PREDICATES
std::enable_if_t<!std::is_floating_point_v<T>, sign_t>
#else
sign_t
#endif
orientation(point<T, N> const & p0, Points const & ... ps)
{
auto o = orientation((ps - p0)...);
if constexpr ((N % 2) == 0)
{
return o;
}
else
{
return inverse(o);
}
}
} }

10
libs/geom/include/psemek/geom/sign.hpp
View file

@ -23,4 +23,14 @@ namespace psemek::geom
return o; return o;
} }
inline sign_t inverse(sign_t s)
{
switch (s)
{
case sign_t::positive: return sign_t::negative;
case sign_t::zero: return sign_t::zero;
case sign_t::negative: return sign_t::positive;
}
}
} }