/*
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* Copyright (C) 2023 Christopher J. Howard
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*
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* This file is part of Antkeeper source code.
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*
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* Antkeeper source code is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Antkeeper source code is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef ANTKEEPER_GEOM_PRIMITIVES_HYPERRECTANGLE_HPP
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#define ANTKEEPER_GEOM_PRIMITIVES_HYPERRECTANGLE_HPP
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#include <engine/math/vector.hpp>
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#include <algorithm>
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#include <cmath>
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namespace geom {
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namespace primitives {
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/**
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* *n*-dimensional axis-aligned rectangle.
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*
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* @tparam T Real type.
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* @tparam N Number of dimensions.
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*/
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template <class T, std::size_t N>
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struct hyperrectangle
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{
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/// Vector type.
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using vector_type = math::vector<T, N>;
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/// Minimum extent of the hyperrectangle.
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vector_type min;
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/// Maximum extent of the hyperrectangle.
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vector_type max;
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/**
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* Tests whether a point is contained within this hyperrectangle.
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*
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* @param point Point to test for containment.
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*
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* @return `true` if the point is contained within this hyperrectangle, `false` otherwise.
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*/
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[[nodiscard]] constexpr bool contains(const vector_type& point) const noexcept
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{
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for (std::size_t i = 0; i < N; ++i)
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{
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if (point[i] < min[i] || point[i] > max[i])
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{
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return false;
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}
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}
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return true;
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}
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/**
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* Tests whether another hyperrectangle is contained within this hyperrectangle.
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*
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* @param other Hyperrectangle to test for containment.
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*
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* @return `true` if the hyperrectangle is contained within this hyperrectangle, `false` otherwise.
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*/
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[[nodiscard]] constexpr bool contains(const hyperrectangle& other) const noexcept
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{
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for (std::size_t i = 0; i < N; ++i)
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{
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if (other.min[i] < min[i] || other.max[i] > max[i])
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{
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return false;
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}
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}
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return true;
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}
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/// Returns the center position of the hyperrectangle.
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[[nodiscard]] inline constexpr vector_type center() const noexcept
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{
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return (min + max) / T{2};
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}
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/**
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* Calculates the signed distance from the hyperrectangle to a point.
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*
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* @param point Input point.
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*
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* @return Signed distance from the hyperrectangle to @p point.
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*/
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[[nodiscard]] T distance(const vector_type& point) const noexcept
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{
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const vector_type d = math::abs(point - center()) - extents();
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return math::length(math::max(vector_type::zero(), d)) + std::min<T>(T{0}, math::max(d));
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}
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/**
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* Calculates the closest point on the hyperrectangle to a point.
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*
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* @param point Input point.
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*
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* @return Closest point on the hyperrectangle to @p point.
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*/
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[[nodiscard]] constexpr vector_type closest_point(const vector_type& point) const noexcept
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{
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const vector_type c = center();
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const vector_type p = point - c;
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const vector_type d = math::abs(p) - extents();
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const T m = std::min<T>(T{0}, math::max(d));
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vector_type r;
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for (std::size_t i = 0; i < N; ++i)
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{
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r[i] = c[i] + std::copysign(d[i] >= m ? d[i] : T{0}, p[i]);
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}
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return r;
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}
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/**
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* Extends the hyperrectangle to include a point.
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*
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* @param point Point to include in the hyperrectangle.
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*/
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void extend(const vector_type& point) noexcept
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{
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min = math::min(min, point);
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max = math::max(max, point);
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}
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/**
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* Extends the hyperrectangle to include another hyperrectangle.
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*
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* @param other Hyperrectangle to include in this hyperrectangle.
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*/
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void extend(const hyperrectangle& other) noexcept
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{
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min = math::min(min, other.min);
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max = math::max(max, other.max);
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}
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/**
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* Tests whether another hyperrectangle intersects this hyperrectangle.
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*
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* @param other Hyperrectangle to test for intersection.
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*
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* @return `true` if the hyperrectangle intersects this hyperrectangle, `false` otherwise.
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*/
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[[nodiscard]] constexpr bool intersects(const hyperrectangle& other) const noexcept
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{
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for (std::size_t i = 0; i < N; ++i)
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{
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if (other.min[i] > max[i] || other.max[i] < min[i])
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{
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return false;
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}
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}
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return true;
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}
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/// Calculates the size of the hyperrectangle.
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[[nodiscard]] inline constexpr vector_type size() const noexcept
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{
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return max - min;
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}
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/// Calculates the extents of the hyperrectangle.
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[[nodiscard]] inline constexpr vector_type extents() const noexcept
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{
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return size() / T{2};
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}
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/**
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* Returns `false` if any coordinates of `min` are greater than `max`.
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*/
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[[nodiscard]] constexpr bool valid() const noexcept
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{
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for (std::size_t i = 0; i < N; ++i)
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{
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if (min[i] > max[i])
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{
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return false;
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}
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}
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return true;
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}
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/// Calculates the volume of the hyperrectangle.
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[[nodiscard]] constexpr T volume() const noexcept
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{
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T v = max[0] - min[0];
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for (std::size_t i = 1; i < N; ++i)
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{
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v *= max[i] - min[i];
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}
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return v;
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}
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/**
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* Returns the nth corner of the hyperrectangle.
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*
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* @param index Index of a corner.
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*/
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[[nodiscard]] constexpr vector_type corner(std::size_t index) const noexcept
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{
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vector_type p;
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for (std::size_t i = 0; i < N; ++i)
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{
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p[i] = ((index >> ((N - 1) - i)) & 1) ? max[i] : min[i];
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}
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return p;
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}
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};
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} // namespace primitives
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using namespace primitives;
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} // namespace geom
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#endif // ANTKEEPER_GEOM_PRIMITIVES_HYPERRECTANGLE_HPP
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