/*
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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_SPHERE_HPP
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#define ANTKEEPER_GEOM_SPHERE_HPP
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#include "geom/bounding-volume.hpp"
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#include "geom/aabb.hpp"
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#include "math/math.hpp"
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#include <algorithm>
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namespace geom {
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/**
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* Bounding sphere.
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*/
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template <class T>
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struct sphere: public bounding_volume<T>
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{
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typedef math::vector<T, 3> vector_type;
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vector_type center;
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T radius;
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sphere(const vector_type& center, T radius);
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sphere();
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virtual bounding_volume_type get_bounding_volume_type() const;
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virtual bool intersects(const sphere<T>& sphere) const;
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virtual bool intersects(const aabb<T>& aabb) const;
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virtual bool contains(const sphere<T>& sphere) const;
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virtual bool contains(const aabb<T>& aabb) const;
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virtual bool contains(const vector_type& point) const;
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};
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template <class T>
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sphere<T>::sphere(const vector_type& center, T radius):
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center(center),
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radius(radius)
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{}
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template <class T>
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sphere<T>::sphere()
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{}
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template <class T>
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inline bounding_volume_type sphere<T>::get_bounding_volume_type() const
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{
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return bounding_volume_type::sphere;
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}
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template <class T>
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bool sphere<T>::intersects(const sphere<T>& sphere) const
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{
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vector_type d = center - sphere.center;
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float r = radius + sphere.radius;
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return (math::dot(d, d) <= r * r);
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}
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template <class T>
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bool sphere<T>::intersects(const aabb<T>& aabb) const
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{
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return aabb.intersects(*this);
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}
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template <class T>
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bool sphere<T>::contains(const sphere<T>& sphere) const
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{
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float containment_radius = radius - sphere.radius;
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if (containment_radius < T(0))
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return false;
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vector_type d = center - sphere.center;
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return (math::dot(d, d) <= containment_radius * containment_radius);
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}
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template <class T>
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bool sphere<T>::contains(const aabb<T>& aabb) const
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{
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T distance = T(0);
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vector_type a = center - aabb.min_point;
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vector_type b = center - aabb.max_point;
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distance += std::max(a.x * a.x, b.x * b.x);
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distance += std::max(a.y * a.y, b.y * b.y);
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distance += std::max(a.z * a.z, b.z * b.z);
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return (distance <= radius * radius);
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}
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template <class T>
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bool sphere<T>::contains(const vector_type& point) const
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{
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vector_type d = center - point;
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return (math::dot(d, d) <= radius * radius);
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}
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} // namespace geom
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#endif // ANTKEEPER_GEOM_SPHERE_HPP
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