vector.hpp

// Copyright Take Vos 2021.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include "../rapid/numeric_array.hpp"
 
namespace hi::inline v1 {
namespace geo {
 
template<int D>
class vector {
public:
    static_assert(D == 2 || D == 3, "Only 2D or 3D vectors are supported");
 
    constexpr vector(vector const&) noexcept = default;
    constexpr vector(vector&&) noexcept = default;
    constexpr vector& operator=(vector const&) noexcept = default;
    constexpr vector& operator=(vector&&) noexcept = default;
 
    template<int E>
    requires(E < D) [[nodiscard]] constexpr vector(vector<E> const& other) noexcept : _v(static_cast<f32x4>(other))
    {
        hi_axiom(holds_invariant());
    }
 
    template<int E>
    requires(E > D) [[nodiscard]] constexpr explicit vector(vector<E> const& other) noexcept : _v(static_cast<f32x4>(other))
    {
        for (std::size_t i = D; i != E; ++i) {
            _v[i] = 0.0f;
        }
        hi_axiom(holds_invariant());
    }
 
    [[nodiscard]] constexpr explicit operator f32x4() const noexcept
    {
        return _v;
    }
 
    [[nodiscard]] constexpr explicit vector(f32x4 const& other) noexcept : _v(other)
    {
        hi_axiom(holds_invariant());
    }
 
    [[nodiscard]] constexpr vector() noexcept : _v(0.0f, 0.0f, 0.0f, 0.0f) {}
 
    [[nodiscard]] constexpr vector(float x, float y) noexcept requires(D == 2) : _v(x, y, 0.0f, 0.0f) {}
 
    [[nodiscard]] constexpr vector(float x, float y, float z = 0.0f) noexcept requires(D == 3) : _v(x, y, z, 0.0f) {}
 
    [[nodiscard]] constexpr float& x() noexcept
    {
        return _v.x();
    }
 
    [[nodiscard]] constexpr float& y() noexcept
    {
        return _v.y();
    }
 
    [[nodiscard]] constexpr float& z() noexcept requires(D == 3)
    {
        return _v.z();
    }
 
    [[nodiscard]] constexpr float const& x() const noexcept
    {
        return _v.x();
    }
 
    [[nodiscard]] constexpr float const& y() const noexcept
    {
        return _v.y();
    }
 
    [[nodiscard]] constexpr float const& z() const noexcept requires(D == 3)
    {
        return _v.z();
    }
 
    [[nodiscard]] constexpr vector operator-() const noexcept
    {
        hi_axiom(holds_invariant());
        return vector{-_v};
    }
 
    template<int E>
    requires(E <= D) constexpr vector& operator+=(vector<E> const& rhs) noexcept
    {
        hi_axiom(holds_invariant() && rhs.holds_invariant());
        _v = _v + static_cast<f32x4>(rhs);
        return *this;
    }
 
    [[nodiscard]] constexpr friend vector operator+(vector const& lhs, vector const& rhs) noexcept
    {
        hi_axiom(lhs.holds_invariant() && rhs.holds_invariant());
        return vector{lhs._v + rhs._v};
    }
 
    [[nodiscard]] constexpr friend vector operator-(vector const& lhs, vector const& rhs) noexcept
    {
        hi_axiom(lhs.holds_invariant() && rhs.holds_invariant());
        return vector{lhs._v - rhs._v};
    }
 
    [[nodiscard]] constexpr friend vector operator*(vector const& lhs, float const& rhs) noexcept
    {
        hi_axiom(lhs.holds_invariant());
        return vector{lhs._v * rhs};
    }
 
    [[nodiscard]] constexpr friend vector operator*(float const& lhs, vector const& rhs) noexcept
    {
        hi_axiom(rhs.holds_invariant());
        return vector{f32x4::broadcast(lhs) * rhs._v};
    }
 
    [[nodiscard]] constexpr friend bool operator==(vector const& lhs, vector const& rhs) noexcept
    {
        hi_axiom(lhs.holds_invariant() && rhs.holds_invariant());
        return lhs._v == rhs._v;
    }
 
    [[nodiscard]] constexpr friend float squared_hypot(vector const& rhs) noexcept
    {
        hi_axiom(rhs.holds_invariant());
        return squared_hypot<element_mask>(rhs._v);
    }
 
    [[nodiscard]] constexpr friend float hypot(vector const& rhs) noexcept
    {
        hi_axiom(rhs.holds_invariant());
        return hypot<element_mask>(rhs._v);
    }
 
    [[nodiscard]] constexpr friend float rcp_hypot(vector const& rhs) noexcept
    {
        hi_axiom(rhs.holds_invariant());
        return rcp_hypot<element_mask>(rhs._v);
    }
 
    [[nodiscard]] constexpr friend vector normalize(vector const& rhs) noexcept
    {
        hi_axiom(rhs.holds_invariant());
        return vector{normalize<element_mask>(rhs._v)};
    }
 
    [[nodiscard]] constexpr friend float dot(vector const& lhs, vector const& rhs) noexcept
    {
        hi_axiom(lhs.holds_invariant() && rhs.holds_invariant());
        return dot<element_mask>(lhs._v, rhs._v);
    }
 
    [[nodiscard]] constexpr friend float det(vector const& lhs, vector const& rhs) noexcept requires (D == 2)
    {
        hi_axiom(lhs.holds_invariant() && rhs.holds_invariant());
        return lhs.x() * rhs.y() - lhs.y() * rhs.x();
    }
 
    template<int E>
    [[nodiscard]] friend constexpr auto min(vector const& lhs, vector<E> const& rhs) noexcept
    {
        return vector<std::max(D, E)>{min(static_cast<f32x4>(lhs), static_cast<f32x4>(rhs))};
    }
 
    template<int E>
    [[nodiscard]] friend constexpr auto max(vector const& lhs, vector<E> const& rhs) noexcept
    {
        return vector<std::max(D, E)>{max(static_cast<f32x4>(lhs), static_cast<f32x4>(rhs))};
    }
 
    [[nodiscard]] friend constexpr vector round(vector const& rhs) noexcept
    {
        return vector{round(static_cast<f32x4>(rhs))};
    }
 
    [[nodiscard]] friend constexpr vector ceil(vector const& rhs) noexcept
    {
        return vector{ceil(static_cast<f32x4>(rhs))};
    }
 
    [[nodiscard]] friend constexpr vector floor(vector const& rhs) noexcept
    {
        return vector{floor(static_cast<f32x4>(rhs))};
    }
 
    [[nodiscard]] constexpr bool holds_invariant() const noexcept
    {
        return _v.w() == 0.0f && (D == 3 || _v.z() == 0.0f);
    }
 
    [[nodiscard]] friend std::string to_string(vector const& rhs) noexcept
    {
        if constexpr (D == 2) {
            return std::format("({}, {})", rhs._v.x(), rhs._v.y());
        } else if constexpr (D == 3) {
            return std::format("({}, {}, {})", rhs._v.x(), rhs._v.y(), rhs._v.z());
        } else {
            hi_static_no_default();
        }
    }
 
    friend std::ostream& operator<<(std::ostream& lhs, vector const& rhs) noexcept
    {
        return lhs << to_string(rhs);
    }
 
private:
    f32x4 _v;
 
    static constexpr std::size_t element_mask = (1_uz << D) - 1;
};
 
[[nodiscard]] constexpr vector<2> cross(vector<2> const& rhs) noexcept
{
    hi_axiom(rhs.holds_invariant());
    return vector<2>{cross_2D(static_cast<f32x4>(rhs))};
}
 
[[nodiscard]] constexpr vector<2> normal(vector<2> const& rhs) noexcept
{
    hi_axiom(rhs.holds_invariant());
    return normalize(cross(rhs));
}
 
[[nodiscard]] constexpr vector<3> normal(vector<3> const& rhs, float angle) noexcept
{
    if (angle != 0.0f) {
        hi_not_implemented();
    }
    return normal(vector<2>{f32x4{rhs}.xy00()});
}
 
[[nodiscard]] constexpr float cross(vector<2> const& lhs, vector<2> const& rhs) noexcept
{
    hi_axiom(lhs.holds_invariant() && rhs.holds_invariant());
    return cross_2D(static_cast<f32x4>(lhs), static_cast<f32x4>(rhs));
}
 
[[nodiscard]] constexpr vector<3> cross(vector<3> const& lhs, vector<3> const& rhs) noexcept
{
    hi_axiom(lhs.holds_invariant() && rhs.holds_invariant());
    return vector<3>{cross_3D(static_cast<f32x4>(lhs), static_cast<f32x4>(rhs))};
}
 
} // namespace geo
 
using vector2 = geo::vector<2>;
using vector3 = geo::vector<3>;
 
} // namespace hi::inline v1
 
template<typename CharT>
struct std::formatter<hi::geo::vector<2>, CharT> {
    auto parse(auto& pc)
    {
        return pc.end();
    }
 
    auto format(hi::geo::vector<2> const& t, auto& fc)
    {
        return std::vformat_to(fc.out(), "({}, {})", std::make_format_args(t.x(), t.y()));
    }
};
 
template<typename CharT>
struct std::formatter<hi::geo::vector<3>, CharT> : std::formatter<float, CharT> {
    auto parse(auto& pc)
    {
        return pc.end();
    }
 
    auto format(hi::geo::vector<3> const& t, auto& fc)
    {
        return std::vformat_to(fc.out(), "({}, {}, {})", std::make_format_args(t.x(), t.y(), t.z()));
    }
};