Crafter.Math/Crafter.Math-Misc.cppm

/*
Crafter.Math
Copyright (C) 2025 Catcrafts
Catcrafts.net

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 3.0 of the License, or (at your option) any later version.

This library 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
*/

module;

#include <cstdint>
#include <stdfloat>
#include <numeric>

export module Crafter.Math:Misc;

export namespace Crafter {
    //-------------------------------------------------------------------------------------
    // DirectXMathMisc.inl -- SIMD C++ Math library
    //
    // Copyright (c) Microsoft Corporation.
    // Licensed under the MIT License.
    //
    // http://go.microsoft.com/fwlink/?LinkID=615560
    //-------------------------------------------------------------------------------------
    constexpr float XM_PI = 3.141592654f;
    constexpr float XM_2PI = 6.283185307f;
    constexpr float XM_1DIVPI = 0.318309886f;
    constexpr float XM_1DIV2PI = 0.159154943f;
    constexpr float XM_PIDIV2 = 1.570796327f;
    constexpr float XM_PIDIV4 = 0.785398163f;


    inline void XMScalarSinCos(float* pSin, float* pCos, float  Value) noexcept
    {
        // Map Value to y in [-pi,pi], x = 2*pi*quotient + remainder.
        float quotient = XM_1DIV2PI * Value;
        if (Value >= 0.0f)
        {
            quotient = static_cast<float>(static_cast<int>(quotient + 0.5f));
        }
        else
        {
            quotient = static_cast<float>(static_cast<int>(quotient - 0.5f));
        }
        float y = Value - XM_2PI * quotient;

        // Map y to [-pi/2,pi/2] with sin(y) = sin(Value).
        float sign;
        if (y > XM_PIDIV2)
        {
            y = XM_PI - y;
            sign = -1.0f;
        }
        else if (y < -XM_PIDIV2)
        {
            y = -XM_PI - y;
            sign = -1.0f;
        }
        else
        {
            sign = +1.0f;
        }

        float y2 = y * y;

        // 11-degree minimax approximation
        *pSin = (((((-2.3889859e-08f * y2 + 2.7525562e-06f) * y2 - 0.00019840874f) * y2 + 0.0083333310f) * y2 - 0.16666667f) * y2 + 1.0f) * y;

        // 10-degree minimax approximation
        float p = ((((-2.6051615e-07f * y2 + 2.4760495e-05f) * y2 - 0.0013888378f) * y2 + 0.041666638f) * y2 - 0.5f) * y2 + 1.0f;
        *pCos = sign * p;
    }

    constexpr float ToRadian(float degrees) {
        return degrees * (std::numbers::pi / 180);
    }
}