sphere.hpp

 
#ifndef UFO_GEOMETRY_SPHERE_HPP
#define UFO_GEOMETRY_SPHERE_HPP
 
// UFO
#include <ufo/geometry/aabb.hpp>
#include <ufo/numeric/vec.hpp>
 
// STL
#include <concepts>
#include <cstddef>
#include <format>
#include <iostream>
#include <numbers>
 
namespace ufo
{
template <std::size_t Dim = 3, std::floating_point T = float>
struct Sphere {
    using value_type = T;
 
    Vec<Dim, T> center_;
 
    T radius;
 
    constexpr Sphere() noexcept = default;
 
    constexpr Sphere(Vec<Dim, T> const& center, T radius) noexcept
        : center_(center), radius(radius)
    {
    }
 
    constexpr Sphere(Sphere const&) noexcept = default;
 
    template <std::convertible_to<T> U>
    constexpr explicit Sphere(Sphere<Dim, U> const& other) noexcept
        : center_(Vec<Dim, T>(other.center())), radius(static_cast<T>(other.radius))
    {
    }
 
    [[nodiscard]] static constexpr std::size_t dimension() noexcept { return Dim; }
 
    [[nodiscard]] constexpr Vec<Dim, T>& center() noexcept { return center_; }
 
    [[nodiscard]] constexpr Vec<Dim, T> const& center() const noexcept { return center_; }
 
    [[nodiscard]] constexpr T diameter() const noexcept { return radius * T(2); }
 
    [[nodiscard]] constexpr AABB<Dim, T> aabb() const noexcept
    {
        return AABB<Dim, T>(center_, radius);
    }
 
    [[nodiscard]] constexpr bool isDegenerate() const noexcept { return radius < T(0); }
 
    [[nodiscard]] constexpr T volume() const noexcept
    {
        if constexpr (1 == Dim) {
            return diameter();
        } else if constexpr (2 == Dim) {
            return std::numbers::pi_v<T> * radius * radius;
        } else if constexpr (3 == Dim) {
            return (T(4) / T(3)) * std::numbers::pi_v<T> * radius * radius * radius;
        } else if constexpr (4 == Dim) {
            return (std::numbers::pi_v<T> * std::numbers::pi_v<T> * radius * radius * radius *
                    radius) /
                   T(2);
        } else {
            return T(0);
        }
    }
 
    [[nodiscard]] bool operator==(Sphere const&) const = default;
};
 
//
// Deduction guides
//
 
template <std::size_t Dim, std::floating_point T>
Sphere(Vec<Dim, T>, T) -> Sphere<Dim, T>;
 
template <std::size_t Dim, std::floating_point T>
std::ostream& operator<<(std::ostream& out, Sphere<Dim, T> const& sphere)
{
    return out << "Center: [" << sphere.center() << "], Radius: " << sphere.radius;
}
 
template <std::floating_point T>
using Sphere1 = Sphere<1, T>;
template <std::floating_point T>
using Sphere2 = Sphere<2, T>;
template <std::floating_point T>
using Sphere3 = Sphere<3, T>;
template <std::floating_point T>
using Sphere4 = Sphere<4, T>;
 
using Sphere1f = Sphere<1, float>;
using Sphere2f = Sphere<2, float>;
using Sphere3f = Sphere<3, float>;
using Sphere4f = Sphere<4, float>;
 
using Sphere1d = Sphere<1, double>;
using Sphere2d = Sphere<2, double>;
using Sphere3d = Sphere<3, double>;
using Sphere4d = Sphere<4, double>;
 
}  // namespace ufo
 
template <std::size_t Dim, std::floating_point T>
  requires std::formattable<T, char>
struct std::formatter<ufo::Sphere<Dim, T>> {
    constexpr auto parse(std::format_parse_context& ctx) { return ctx.begin(); }
 
    auto format(ufo::Sphere<Dim, T> const& sphere, std::format_context& ctx) const
    {
        return std::format_to(ctx.out(), "Center: [{}], Radius: {}", sphere.center(),
                              sphere.radius);
    }
};
 
#endif  // UFO_GEOMETRY_SPHERE_HPP