geometry_ops.h

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// SPDX-License-Identifier: GPL-2.0-only
//
// Copyright (c) 2006-2008 Marc Brooker and Michael Inggs
// Copyright (c) 2008-present FERS Contributors (see AUTHORS.md).
//
// See the GNU GPLv2 LICENSE file in the FERS project root for more information.
 
/**
 * @file geometry_ops.h
 * @brief Classes and operations for 3D geometry.
 */
 
#pragma once
 
#include <array>
#include <cmath>
 
#include "core/config.h"
 
namespace math
{
    class Vec3;
 
    /**
     * @class Matrix3
     * @brief A class representing a 3x3 matrix.
     */
    class Matrix3
    {
    public:
        std::array<RealType, 9> elements{}; ///< The 3x3 matrix elements
 
        /**
         * @brief Get the matrix data as a constant pointer.
         *
         * @return A constant pointer to the matrix elements.
         */
        [[nodiscard]] const RealType* getData() const noexcept { return elements.data(); }
 
        /**
         * @brief Get the matrix data as a modifiable pointer.
         *
         * @return A pointer to the matrix elements.
         */
        RealType* getData() noexcept { return elements.data(); }
    };
 
    /**
     * @class SVec3
     * @brief A class representing a vector in spherical coordinates.
     */
    class SVec3
    {
    public:
        RealType length{}; ///< The length of the vector
        RealType azimuth{}; ///< The azimuth angle of the vector
        RealType elevation{}; ///< The elevation angle of the vector
 
        SVec3() noexcept = default;
        SVec3(const SVec3&) noexcept = default;
        SVec3(SVec3&&) noexcept = default;
        SVec3& operator=(const SVec3&) noexcept = default;
        SVec3& operator=(SVec3&&) noexcept = default;
 
        /**
         * @brief Parameterized constructor for SVec3.
         *
         * @param length The length or magnitude of the vector.
         * @param azimuth The azimuthal angle of the vector.
         * @param elevation The elevation angle of the vector.
         */
        constexpr SVec3(const RealType length, const RealType azimuth, const RealType elevation) noexcept :
            length(length), azimuth(azimuth), elevation(elevation)
        {
        }
 
        /**
         * @brief Constructs a spherical vector from a rectangular Vec3.
         *
         * @param vec A rectangular vector (Vec3) to convert.
         */
        explicit SVec3(const Vec3& vec) noexcept;
 
        /**
         * @brief Scalar multiplication assignment for SVec3.
         *
         * @param b The scalar value.
         * @return A reference to the updated SVec3.
         */
        SVec3& operator*=(RealType b) noexcept;
 
        /**
         * @brief Scalar division assignment for SVec3.
         *
         * @param b The scalar value.
         * @return A reference to the updated SVec3.
         */
        SVec3& operator/=(RealType b) noexcept;
    };
 
    /**
     * @class Vec3
     * @brief A class representing a vector in rectangular coordinates.
     */
    class Vec3
    {
    public:
        RealType x{}; ///< The x component of the vector
        RealType y{}; ///< The y component of the vector
        RealType z{}; ///< The z component of the vector
 
        Vec3() noexcept = default;
        Vec3(const Vec3&) noexcept = default;
        Vec3(Vec3&&) noexcept = default;
        Vec3& operator=(const Vec3&) noexcept = default;
        Vec3& operator=(Vec3&&) noexcept = default;
 
        /**
         * @brief Parameterized constructor for Vec3.
         *
         * @param x The x component.
         * @param y The y component.
         * @param z The z component.
         */
        constexpr Vec3(const RealType x, const RealType y, const RealType z) noexcept : x(x), y(y), z(z) {}
 
        /**
         * @brief Constructs a rectangular vector from a spherical SVec3.
         *
         * @param svec A spherical vector (SVec3) to convert.
         */
        explicit Vec3(const SVec3& svec) noexcept;
 
        /**
         * @brief Addition assignment operator for Vec3.
         *
         * @param b The vector to add.
         * @return A reference to the updated Vec3.
         */
        Vec3& operator+=(const Vec3& b) noexcept;
 
        /**
         * @brief Subtraction assignment operator for Vec3.
         *
         * @param b The vector to subtract.
         * @return A reference to the updated Vec3.
         */
        Vec3& operator-=(const Vec3& b) noexcept;
 
        /**
         * @brief Multiplication assignment operator for Vec3.
         *
         * @param b The vector to multiply by.
         * @return A reference to the updated Vec3.
         */
        Vec3& operator*=(const Vec3& b) noexcept;
 
        /**
         * @brief Matrix multiplication assignment for Vec3.
         *
         * @param m The matrix to multiply by.
         * @return A reference to the updated Vec3.
         */
        Vec3& operator*=(const Matrix3& m) noexcept;
 
        /**
         * @brief Scalar multiplication assignment for Vec3.
         *
         * @param b The scalar value.
         * @return A reference to the updated Vec3.
         */
        Vec3& operator*=(RealType b) noexcept;
 
        /**
         * @brief Scalar division assignment for Vec3.
         *
         * @param b The scalar value.
         * @return A reference to the updated Vec3.
         */
        Vec3& operator/=(RealType b) noexcept;
 
        /**
         * @brief Addition operator for Vec3.
         *
         * @param value The scalar value to add.
         * @return The resulting vector.
         */
        Vec3 operator+(const RealType value) const { return {x + value, y + value, z + value}; }
 
        Vec3 operator-() const { return {-x, -y, -z}; }
 
        /**
         * @brief Calculates the length (magnitude) of the vector.
         *
         * @return The length of the vector.
         */
        [[nodiscard]] RealType length() const noexcept { return std::sqrt(x * x + y * y + z * z); }
    };
 
    /**
     * @brief Computes the dot product of two Vec3 vectors.
     *
     * @param a The first vector.
     * @param b The second vector.
     * @return The dot product of the vectors.
     */
    inline RealType dotProduct(const Vec3& a, const Vec3& b) noexcept { return a.x * b.x + a.y * b.y + a.z * b.z; }
 
    // Cross product
    // Note: This function is not used in the codebase
    /*inline Vec3 crossProduct(const Vec3& a, const Vec3& b) noexcept
    {
        return {a.y * b.z - a.z * b.y, a.z * b.x - a.x * b.z, a.x * b.y - a.y * b.x};
    }*/
 
    /// Multiplies two Vec3 vectors component-wise
    inline Vec3 operator*(const Vec3& a, const Vec3& b) noexcept { return {a.x * b.x, a.y * b.y, a.z * b.z}; }
 
    /// Adds two Vec3 vectors component-wise
    inline Vec3 operator+(const Vec3& a, const Vec3& b) noexcept { return {a.x + b.x, a.y + b.y, a.z + b.z}; }
 
    /// Subtracts two Vec3 vectors component-wise
    inline Vec3 operator-(const Vec3& a, const Vec3& b) noexcept { return {a.x - b.x, a.y - b.y, a.z - b.z}; }
 
    /// Divides two Vec3 vectors component-wise
    inline Vec3 operator/(const Vec3& a, const Vec3& b) { return {a.x / b.x, a.y / b.y, a.z / b.z}; }
 
    /// Multiplies a Vec3 vector by a scalar value
    inline Vec3 operator*(const Vec3& a, const RealType b) noexcept { return {a.x * b, a.y * b, a.z * b}; }
 
    /// Divides a Vec3 vector by a scalar value
    inline Vec3 operator/(const Vec3& a, const RealType b) noexcept { return {a.x / b, a.y / b, a.z / b}; }
 
    /// Divides a scalar value by a Vec3 vector
    inline Vec3 operator/(const RealType a, const Vec3& b) noexcept { return {a / b.x, a / b.y, a / b.z}; }
 
    /// Adds two SVec3 vectors
    SVec3 operator+(const SVec3& a, const SVec3& b) noexcept;
 
    /// Subtracts two SVec3 vectors
    SVec3 operator-(const SVec3& a, const SVec3& b) noexcept;
}