💿🐜 Antkeeper source code
https://antkeeper.com
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139 lines
3.5 KiB
139 lines
3.5 KiB
/*
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* Copyright (C) 2021 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_PRIMITIVE_HYPERSPHERE_HPP
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#define ANTKEEPER_GEOM_PRIMITIVE_HYPERSPHERE_HPP
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#include "math/constants.hpp"
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#include "math/vector.hpp"
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namespace geom {
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namespace primitive {
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/**
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* *n*-dimensional sphere.
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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 hypersphere
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{
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typedef math::vector<T, N> vector_type;
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/// Hypersphere center.
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vector_type center;
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/// Hypersphere radius.
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T radius;
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/**
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* Tests whether a point is contained within this hypersphere.
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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 hypersphere, `false` otherwise.
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*/
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constexpr bool contains(const vector_type& point) const noexcept
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{
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return math::sqr_distance(center, point) <= radius * radius;
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}
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/**
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* Tests whether another hypersphere is contained within this hypersphere.
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*
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* @param other Hypersphere to test for containment.
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*
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* @return `true` if the hypersphere is contained within this hypersphere, `false` otherwise.
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*/
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constexpr bool contains(const hypersphere& other) const noexcept
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{
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const T containment_radius = radius - other.radius;
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if (containment_radius < T{0})
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return false;
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return math::sqr_distance(center, other.center) <= containment_radius * containment_radius;
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}
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/**
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* Calculates the signed distance from the hypersphere 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 hypersphere to @p point.
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*/
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T distance(const vector_type& point) const noexcept
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{
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return math::distance(center, point) - radius;
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}
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/**
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* Tests whether another hypersphere intersects this hypersphere.
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*
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* @param other Hypersphere to test for intersection.
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*
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* @return `true` if the hypersphere intersects this hypersphere, `false` otherwise.
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*/
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constexpr bool intersects(const hypersphere& other) const noexcept
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{
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const T intersection_radius = radius + other.radius;
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return math::sqr_distance(center, other.center) <= intersection_radius * intersection_radius;
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}
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/**
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* Volume calculation helper function.
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*
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* @tparam M Dimension.
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*
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* @param r Radius.
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*
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* @return Volume.
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*/
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/// @private
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/// @{
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template <std::size_t M>
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static constexpr T volume(T r) noexcept
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{
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return (math::two_pi<T> / static_cast<T>(M)) * r * r * volume<M - 2>(r);
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}
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template <>
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static constexpr T volume<1>(T r) noexcept
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{
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return r * T{2};
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}
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template <>
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static constexpr T volume<0>(T r) noexcept
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{
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return T{1};
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}
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/// @}
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/// Calculates the volume of the hypersphere.
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inline constexpr T volume() const noexcept
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{
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return volume<N>(radius);
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}
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};
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} // namespace primitive
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} // namespace geom
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#endif // ANTKEEPER_GEOM_PRIMITIVE_HYPERSPHERE_HPP
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