rotate3.hpp

// Copyright Take Vos 2021-2022.
// 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 "vector3.hpp"
 
namespace hi { inline namespace v1 {
 
class rotate3 {
public:
    using array_type = simd<float, 4>;
    using value_type = array_type::value_type;
 
    constexpr rotate3(rotate3 const&) noexcept = default;
    constexpr rotate3(rotate3&&) noexcept = default;
    constexpr rotate3& operator=(rotate3 const&) noexcept = default;
    constexpr rotate3& operator=(rotate3&&) noexcept = default;
    constexpr rotate3() noexcept : _v(0.0f, 0.0f, 1.0f, 0.0f) {}
 
    [[nodiscard]] rotate3(float angle, vector3 axis) noexcept : _v()
    {
        hi_axiom(axis.holds_invariant());
        hi_axiom(std::abs(hypot(axis) - 1.0f) < 0.0001f);
 
        hilet half_angle = angle * 0.5f;
        hilet C = std::cos(half_angle);
        hilet S = std::sin(half_angle);
 
        _v = static_cast<f32x4>(axis) * S;
        _v.w() = C;
    }
 
    [[nodiscard]] constexpr explicit operator array_type() const noexcept
    {
        return _v;
    }
 
 
 
    
 
    //std::pair<float, vector3> angle_and_axis() const noexcept
    //{
    //    hilet rcp_length = rcp_hypot<0b0111>(_v);
    //    hilet length = 1.0f / rcp_length;
    //
    //    return {2.0f * std::atan2(length), vector3{_v.xyz0() * rcp_length}};
    //}
 
private:
    array_type _v;
};
 
}} // namespace hi::v1