aabb.hpp

/*
 Copyright (c) 2026 ETIB Corporation
 
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 */
 
#pragma once
 
#include <algorithm>
#include <concepts>
#include <cstddef>
#include <iterator>
#include <limits>
#include <ostream>
#include <span>
#include <type_traits>
 
#include <glm/geometric.hpp>
#include <glm/vec3.hpp>
 
#include <utility/math/vector.hpp>
 
namespace utility::math
{
    template<CanBeVectorComponent T>
    class Aabb
    {
        static_assert(
            std::is_floating_point_v<T>,
            "Aabb requires a floating-point component type (float or double)");
 
        public:
        Aabb(void)
            : _min(std::numeric_limits<T>::max())
            , _max(std::numeric_limits<T>::lowest())
        {
        }
 
        Aabb(const Vector<T, 3> &min, const Vector<T, 3> &max)
            : _min(min)
            , _max(max)
        {
        }
 
        template<std::input_iterator Iterator,
                 std::sentinel_for<Iterator> Sentinel>
        static Aabb fromPoints(Iterator first, Sentinel last)
        {
            Aabb box;
            for (; first != last; ++first) {
                box.include(*first);
            }
            return box;
        }
 
        static Aabb fromPoints(std::span<const Vector<T, 3>> points)
        {
            return fromPoints(points.begin(), points.end());
        }
 
        void include(const Vector<T, 3> &point) noexcept
        {
            for (std::size_t i = 0; i < 3; ++i) {
                _min[i] = std::min(_min[i], point[i]);
                _max[i] = std::max(_max[i], point[i]);
            }
        }
 
        void include(const Aabb &other) noexcept
        {
            if (other.isEmpty()) {
                return;
            }
            include(other._min);
            include(other._max);
        }
 
        [[nodiscard]] Vector<T, 3> center(void) const noexcept
        {
            return _min * T { 0.5 } + _max * T { 0.5 };
        }
 
        [[nodiscard]] Vector<T, 3> extents(void) const noexcept
        {
            return isEmpty() ? Vector<T, 3>(T { 0 }) : (_max - _min);
        }
 
        [[nodiscard]] Vector<T, 3> halfSize(void) const noexcept
        {
            return extents() * T { 0.5 };
        }
 
        [[nodiscard]] T radius(void) const noexcept
        {
            return static_cast<T>(glm::length(
                static_cast<const glm::vec<3, T> &>(halfSize())));
        }
 
        [[nodiscard]] Vector<T, 3>
            positiveVertex(const Vector<T, 3> &normal) const noexcept
        {
            Vector<T, 3> result;
            for (std::size_t i = 0; i < 3; ++i) {
                result[i] = (normal[i] >= T { 0 }) ? _max[i] : _min[i];
            }
            return result;
        }
 
        [[nodiscard]] bool contains(const Vector<T, 3> &point) const noexcept
        {
            if (isEmpty()) {
                return false;
            }
            for (std::size_t i = 0; i < 3; ++i) {
                if (point[i] < _min[i] || point[i] > _max[i]) {
                    return false;
                }
            }
            return true;
        }
 
        [[nodiscard]] bool intersects(const Aabb &other) const noexcept
        {
            if (isEmpty() || other.isEmpty()) {
                return false;
            }
            for (std::size_t i = 0; i < 3; ++i) {
                if (_min[i] > other._max[i] || other._min[i] > _max[i]) {
                    return false;
                }
            }
            return true;
        }
 
        [[nodiscard]] bool isEmpty(void) const noexcept
        {
            for (std::size_t i = 0; i < 3; ++i) {
                if (_min[i] > _max[i]) {
                    return true;
                }
            }
            return false;
        }
 
        [[nodiscard]] Vector<T, 3> getMin(void) const noexcept
        {
            return _min;
        }
 
        [[nodiscard]] Vector<T, 3> getMax(void) const noexcept
        {
            return _max;
        }
 
        private:
        Vector<T, 3> _min;  
        Vector<T, 3> _max;  
    };
 
    using AabbF = Aabb<float>;
 
    using AabbD = Aabb<double>;
 
    std::ostream &operator<<(std::ostream &stream, const AabbF &box);
 
    std::ostream &operator<<(std::ostream &stream, const AabbD &box);
 
}    // namespace utility::math