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Add ray-simplex intersection

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This commit is contained in:
Nikita Lisitsa 2020-09-26 23:23:40 +03:00
parent d3b306f29e
commit 81cafa6f05
1 changed files with 40 additions and 0 deletions
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40
libs/geom/include/psemek/geom/intersection.hpp
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@ -7,7 +7,9 @@
#include <psemek/geom/box.hpp>
#include <psemek/geom/orientation.hpp>
#include <psemek/geom/contains.hpp>
#include <psemek/geom/gauss.hpp>
#include <optional>
#include <variant>
#include <type_traits>
@ -128,4 +130,42 @@ namespace psemek::geom
return !intersection(r, b).empty();
}
template <typename T, std::size_t N>
std::optional<T> intersection(ray<T, N> const & r, simplex<point<T, N>, N - 1> const & s)
{
geom::matrix<T, N, N> m;
geom::vector<T, N> b;
for (std::size_t i = 0; i < N; ++i)
{
m[i][0] = r.direction[i];
b[i] = s[0][i] - r.origin[i];
for (std::size_t j = 1; j < N; ++j)
{
m[i][j] = s[j][i] - s[0][i];
}
}
if (!geom::gauss(m, b))
return std::nullopt;
T sum{};
for (std::size_t j = 1; j < N; ++j)
{
if (b[j] >= T{}) return std::nullopt;
sum += (-b[j]);
}
if (sum > T{1}) return std::nullopt;
return b[0];
}
template <typename T, std::size_t N>
bool intersect(ray<T, N> const & r, simplex<T, N> const & s)
{
return static_cast<bool>(intersection(r, s));
}
}