prism/engine/math/include/vector.hpp

#pragma once

#include <array>
#include <cmath>
#include <type_traits>
#include <typeinfo>

namespace prism {
#define DEFINE_OPERATORS(Size)                                                                                         \
    constexpr Vector(const T scalar = T(0)) {                                                                          \
        for (std::size_t i = 0; i < (Size); i++)                                                                       \
            data[i] = scalar;                                                                                          \
    }                                                                                                                  \
    constexpr T& operator[](const size_t index) { return data[index]; }                                                \
    constexpr T operator[](const size_t index) const { return data[index]; }                                           \
    constexpr Vector& operator+=(const Vector rhs) {                                                                   \
        for (std::size_t i = 0; i < (Size); i++)                                                                       \
            data[i] += rhs[i];                                                                                         \
        return *this;                                                                                                  \
    }                                                                                                                  \
    constexpr Vector& operator-=(const Vector rhs) {                                                                   \
        for (std::size_t i = 0; i < (Size); i++)                                                                       \
            data[i] -= rhs[i];                                                                                         \
        return *this;                                                                                                  \
    }                                                                                                                  \
    constexpr Vector& operator*=(const Vector rhs) {                                                                   \
        for (std::size_t i = 0; i < (Size); i++)                                                                       \
            data[i] *= rhs[i];                                                                                         \
        return *this;                                                                                                  \
    }                                                                                                                  \
    constexpr Vector& operator/=(const T scalar) {                                                                     \
        for (std::size_t i = 0; i < (Size); i++)                                                                       \
            data[i] /= scalar;                                                                                         \
        return *this;                                                                                                  \
    }                                                                                                                  \
    constexpr T* ptr() const { return data.data(); }                                                                   \
    constexpr T* ptr() { return data.data(); }                                                                         \
    constexpr Vector operator-() const {                                                                               \
        Vector vec;                                                                                                    \
        for (std::size_t i = 0; i < (Size); i++)                                                                       \
            vec[i] = -data[i];                                                                                         \
        return vec;                                                                                                    \
    }

    template<std::size_t N, class T> struct Vector { std::array<T, N> data; };

    template<class T> struct Vector<2, T> {
        constexpr Vector(const T x_, const T y_) {
            x = x_;
            y = y_;
        }

        DEFINE_OPERATORS(2)

        union {
            std::array<T, 2> data;

            struct {
                T x, y;
            };
        };
    };

    template<class T> struct Vector<3, T> {
        constexpr Vector(const T x_, const T y_, const T z_) {
            x = x_;
            y = y_;
            z = z_;
        }

        DEFINE_OPERATORS(3)

        union {
            std::array<T, 3> data;

            struct {
                T x, y, z;
            };
        };
    };

    template<class T> struct alignas(16) Vector<4, T> {
        constexpr Vector(const T x_, const T y_, const T z_, const T w_) {
            x = x_;
            y = y_;
            z = z_;
            w = w_;
        }

        constexpr Vector(const Vector<3, T>& v, const float w = 0.0f) : x(v.x), y(v.y), z(v.z), w(w) {}

        DEFINE_OPERATORS(4)

        union {
            std::array<T, 4> data;

            struct {
                T x, y, z, w;
            };

            struct {
                Vector<3, T> xyz;
                T padding_xyz;
            };
        };
    };

    using float2 = Vector<2, float>;
    using float3 = Vector<3, float>;
    using float4 = Vector<4, float>;

    template<std::size_t N, class T> constexpr inline T dot(const Vector<N, T> lhs, const Vector<N, T> rhs) {
        T product = T(0.0);

        for (std::size_t i = 0; i < N; i++)
            product += lhs[i] * rhs[i];

        return product;
    }

    template<std::size_t N, class T> constexpr inline T length(const Vector<N, T> vec) {
        return sqrtf(dot(vec, vec));
    }

    template<std::size_t N, class T>
    constexpr inline Vector<N, T> lerp(const Vector<N, T> a, const Vector<N, T> b, const T t) {
        Vector<N, T> vec;
        for (std::size_t i = 0; i < N; i++)
            vec[i] = (T(1) - t) * a[i] + t * b[i];

        return vec;
    }

    template<std::size_t N, class T> constexpr inline Vector<N, T> normalize(const Vector<N, T> vec) {
        Vector<N, T> result;

        const float len = length(vec);
        for (std::size_t i = 0; i < N; i++)
            result[i] = vec[i] / len;

        return result;
    }

    constexpr inline float3 cross(const float3 u, const float3 v) {
        return float3(u.y * v.z - u.z * v.y, u.z * v.x - u.x * v.z, u.x * v.y - u.y * v.x);
    }

    inline float distance(const float3 lhs, const float3 rhs) {
        const float diffX = lhs.x - rhs.x;
        const float diffY = lhs.y - rhs.y;
        const float diffZ = lhs.z - rhs.z;

        return std::sqrt((diffX * diffX) + (diffY * diffY) + (diffZ * diffZ));
    }

    template<std::size_t N, class T> constexpr inline T norm(const Vector<N, T> vec) {
        T val = T(0);
        for (std::size_t i = 0; i < N; i++)
            val += abs(vec[i]);

        return sqrtf(dot(vec, vec));
    }
} // namespace prism

template<std::size_t N, class T>
constexpr inline bool operator==(const prism::Vector<N, T> lhs, const prism::Vector<N, T> rhs) {
    bool is_equal = true;
    for (std::size_t i = 0; i < N; i++) {
        if (lhs[i] != rhs[i])
            is_equal = false;
    }

    return is_equal;
}

template<std::size_t N, class T>
constexpr inline bool operator!=(const prism::Vector<N, T> lhs, const prism::Vector<N, T> rhs) {
    return !(lhs == rhs);
}

template<std::size_t N, class T>
constexpr inline prism::Vector<N, T> operator-(const prism::Vector<N, T> lhs, const prism::Vector<N, T> rhs) {
    prism::Vector<N, T> vec;
    for (std::size_t i = 0; i < N; i++)
        vec[i] = lhs[i] - rhs[i];

    return vec;
}

template<std::size_t N, class T>
constexpr inline prism::Vector<N, T> operator+(const prism::Vector<N, T> lhs, const prism::Vector<N, T> rhs) {
    prism::Vector<N, T> vec;
    for (std::size_t i = 0; i < N; i++)
        vec[i] = lhs[i] + rhs[i];

    return vec;
}

template<std::size_t N, class T>
constexpr inline prism::Vector<N, T> operator*(const prism::Vector<N, T> lhs, const prism::Vector<N, T> rhs) {
    prism::Vector<N, T> vec;
    for (std::size_t i = 0; i < N; i++)
        vec[i] = lhs[i] * rhs[i];

    return vec;
}

template<std::size_t N, class T>
constexpr inline prism::Vector<N, T> operator+(const prism::Vector<N, T> lhs, const T scalar) {
    prism::Vector<N, T> vec;
    for (std::size_t i = 0; i < N; i++)
        vec[i] = lhs[i] + scalar;

    return vec;
}

template<std::size_t N, class T>
constexpr inline prism::Vector<N, T> operator*(const prism::Vector<N, T> lhs, const T scalar) {
    prism::Vector<N, T> vec;
    for (std::size_t i = 0; i < N; i++)
        vec[i] = lhs[i] * scalar;

    return vec;
}

template<std::size_t N, class T>
constexpr inline prism::Vector<N, T> operator/(const prism::Vector<N, T> lhs, const prism::Vector<N, T> rhs) {
    prism::Vector<N, T> vec;
    for (std::size_t i = 0; i < N; i++)
        vec[i] = lhs[i] / rhs[i];

    return vec;
}

template<std::size_t N, class T>
constexpr inline prism::Vector<N, T> operator/(const prism::Vector<N, T> lhs, const T scalar) {
    prism::Vector<N, T> vec;
    for (std::size_t i = 0; i < N; i++)
        vec[i] = lhs[i] / scalar;

    return vec;
}