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- /*
- * Copyright (C) 2021 Christopher J. Howard
- *
- * This file is part of Antkeeper source code.
- *
- * Antkeeper source code is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * Antkeeper source code is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
- */
-
- #ifndef ANTKEEPER_GEOM_AABB_HPP
- #define ANTKEEPER_GEOM_AABB_HPP
-
- #include "bounding-volume.hpp"
- #include "sphere.hpp"
- #include "math/math.hpp"
- #include <limits>
-
- namespace geom {
-
- /**
- * Axis-aligned bounding box.
- */
- template <class T>
- struct aabb: public bounding_volume<T>
- {
- typedef math::vector<T, 3> vector_type;
- typedef math::matrix<T, 4, 4> matrix_type;
- typedef math::transform<T> transform_type;
-
- vector_type min_point;
- vector_type max_point;
-
- /**
- * Transforms an AABB.
- *
- * @param a AABB to be transformed.
- * @param t Transform by which the AABB should be transformed.
- * @return Transformed AABB.
- */
- static aabb transform(const aabb& a, const transform_type& t);
-
- /**
- * Transforms an AABB.
- *
- * @param a AABB to be transformed.
- * @param m Matrix by which the AABB should be transformed.
- * @return Transformed AABB.
- */
- static aabb transform(const aabb& a, const matrix_type& m);
-
- aabb(const vector_type& min_point, const vector_type& max_point);
- aabb();
-
- virtual bounding_volume_type get_bounding_volume_type() const;
- virtual bool intersects(const sphere<T>& sphere) const;
- virtual bool intersects(const aabb<T>& aabb) const;
- virtual bool contains(const sphere<T>& sphere) const;
- virtual bool contains(const aabb<T>& aabb) const;
- virtual bool contains(const vector_type& point) const;
-
- /**
- * Returns the position of the specified corner.
- *
- * @param index Index of a corner.
- * @return Position of the specified corner.
- */
- vector_type corner(int index) const noexcept;
- };
-
- template <class T>
- aabb<T> aabb<T>::transform(const aabb& a, const transform_type& t)
- {
- vector_type min_point = {std::numeric_limits<T>::infinity(), std::numeric_limits<T>::infinity(), std::numeric_limits<T>::infinity()};
- vector_type max_point = {-std::numeric_limits<T>::infinity(), -std::numeric_limits<T>::infinity(), -std::numeric_limits<T>::infinity()};
-
- for (std::size_t i = 0; i < 8; ++i)
- {
- vector_type transformed_corner = math::mul(t, a.corner(i));
-
- for (std::size_t j = 0; j < 3; ++j)
- {
- min_point[j] = std::min<T>(min_point[j], transformed_corner[j]);
- max_point[j] = std::max<T>(max_point[j], transformed_corner[j]);
- }
- }
-
- return {min_point, max_point};
- }
-
- template <class T>
- aabb<T> aabb<T>::transform(const aabb& a, const matrix_type& m)
- {
- vector_type min_point = {std::numeric_limits<T>::infinity(), std::numeric_limits<T>::infinity(), std::numeric_limits<T>::infinity()};
- vector_type max_point = {-std::numeric_limits<T>::infinity(), -std::numeric_limits<T>::infinity(), -std::numeric_limits<T>::infinity()};
-
- for (std::size_t i = 0; i < 8; ++i)
- {
- vector_type corner = a.corner(i);
- math::vector<T, 4> transformed_corner = math::mul(m, math::vector<T, 4>{corner.x, corner.y, corner.z, T(1)});
-
- for (std::size_t j = 0; j < 3; ++j)
- {
- min_point[j] = std::min<T>(min_point[j], transformed_corner[j]);
- max_point[j] = std::max<T>(max_point[j], transformed_corner[j]);
- }
- }
-
- return {min_point, max_point};
- }
-
- template <class T>
- aabb<T>::aabb(const vector_type& min_point, const vector_type& max_point):
- min_point(min_point),
- max_point(max_point)
- {}
-
- template <class T>
- aabb<T>::aabb()
- {}
-
- template <class T>
- inline bounding_volume_type aabb<T>::get_bounding_volume_type() const
- {
- return bounding_volume_type::aabb;
- }
-
- template <class T>
- bool aabb<T>::intersects(const sphere<T>& sphere) const
- {
- const vector_type radius_vector = {sphere.radius, sphere.radius, sphere.radius};
- return aabb<T>(min_point - radius_vector, max_point + radius_vector).contains(sphere.center);
- }
-
- template <class T>
- bool aabb<T>::intersects(const aabb<T>& aabb) const
- {
- if (max_point.x < aabb.min_point.x || min_point.x > aabb.max_point.x)
- return false;
- if (max_point.y < aabb.min_point.y || min_point.y > aabb.max_point.y)
- return false;
- if (max_point.z < aabb.min_point.z || min_point.z > aabb.max_point.z)
- return false;
- return true;
- }
-
- template <class T>
- bool aabb<T>::contains(const sphere<T>& sphere) const
- {
- if (sphere.center.x - sphere.radius < min_point.x || sphere.center.x + sphere.radius > max_point.x)
- return false;
- if (sphere.center.y - sphere.radius < min_point.y || sphere.center.y + sphere.radius > max_point.y)
- return false;
- if (sphere.center.z - sphere.radius < min_point.z || sphere.center.z + sphere.radius > max_point.z)
- return false;
- return true;
- }
-
- template <class T>
- bool aabb<T>::contains(const aabb<T>& aabb) const
- {
- if (aabb.min_point.x < min_point.x || aabb.max_point.x > max_point.x)
- return false;
- if (aabb.min_point.y < min_point.y || aabb.max_point.y > max_point.y)
- return false;
- if (aabb.min_point.z < min_point.z || aabb.max_point.z > max_point.z)
- return false;
- return true;
- }
-
- template <class T>
- bool aabb<T>::contains(const vector_type& point) const
- {
- if (point.x < min_point.x || point.x > max_point.x)
- return false;
- if (point.y < min_point.y || point.y > max_point.y)
- return false;
- if (point.z < min_point.z || point.z > max_point.z)
- return false;
- return true;
- }
-
- template <class T>
- typename aabb<T>::vector_type aabb<T>::corner(int index) const noexcept
- {
- return
- {
- ((index >> 2) & 1) ? max_point[0] : min_point[0],
- ((index >> 1) & 1) ? max_point[1] : min_point[1],
- ((index >> 0) & 1) ? max_point[2] : min_point[2]
- };
- }
-
- } // namespace geom
-
- #endif // ANTKEEPER_GEOM_AABB_HPP
-
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