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Add geom::polygon_contains

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This commit is contained in:
Nikita Lisitsa 2022-12-15 20:10:57 +03:00
parent 9f045c18a8
commit d01a8186d8
1 changed files with 28 additions and 0 deletions
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28
libs/geom/include/psemek/geom/contains.hpp
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@ -5,6 +5,7 @@
#include <psemek/geom/point.hpp> #include <psemek/geom/point.hpp>
#include <psemek/geom/simplex.hpp> #include <psemek/geom/simplex.hpp>
#include <psemek/geom/orientation.hpp> #include <psemek/geom/orientation.hpp>
#include <psemek/util/range.hpp>
namespace psemek::geom namespace psemek::geom
{ {
@ -55,4 +56,31 @@ namespace psemek::geom
return contains(default_robust_tag, t, p); return contains(default_robust_tag, t, p);
} }
template <typename Iterator, typename T>
bool polygon_contains(Iterator begin, Iterator end, point<T, 2> const & p)
{
int count = 0;
for (auto it = begin, prev = std::prev(end); it != end; prev = it++)
{
auto p0 = *prev;
auto p1 = *it;
if (p0[1] > p1[1])
std::swap(p0, p1);
if (p0[1] <= p[1] && p[1] < p1[1])
{
if (orientation(p0, p1, p) == sign_t::positive)
++count;
}
}
return (count % 2) == 1;
}
template <typename Polygon, typename T>
bool polygon_contains(Polygon const & polygon, point<T, 2> const & p)
{
return polygon_contains(util::begin(polygon), util::end(polygon), p);
}
} }