vec3.hpp

#ifndef RAY_TRACING_IN_A_WEEKEND_VEC3_H
#define RAY_TRACING_IN_A_WEEKEND_VEC3_H

#include <cmath>
#include <vector>


class vec3 {
public:
    vec3() = default;

    vec3(double e0, double e1, double e2)
    {
        e = {e0, e1, e2};
    }

    inline double x() const { return e[0]; }

    inline double y() const { return e[1]; }

    inline double z() const { return e[2]; }

    inline double r() const { return e[0]; }

    inline double g() const { return e[1]; }

    inline double b() const { return e[2]; }

    inline const vec3 &operator+() const { return *this; }

    inline vec3 operator-() const { return vec3(-e[0], -e[1], -e[2]); }

    inline double operator[](int i) const { return e[i]; }

    inline double &operator[](int i) { return e[i]; };

    inline vec3 &operator+=(const vec3 &v2);

    inline vec3 &operator-=(const vec3 &v);

    inline vec3 &operator*=(const vec3 &v);

    inline vec3 &operator/=(const vec3 &v);

    inline vec3 &operator*=(const double t);

    inline vec3 &operator/=(const double t);

    inline double length() const { return sqrt(e[0] * e[0] + e[1] * e[1] + e[2] * e[2]); }

    inline double squared_length() const { return e[0] * e[0] + e[1] * e[1] + e[2] * e[2]; }

    inline void make_unit_vector();

    std::vector<double> e{0, 0, 0};
};

//------------- impl

inline std::istream &operator>>(std::istream &is, vec3 &t) {
    is >> t.e[0] >> t.e[1] >> t.e[2];
    return is;
}

inline std::ostream &operator<<(std::ostream &os, const vec3 &t) {
    os << t.e[0] << " " << t.e[1] << " " << t.e[2];
    return os;
}

inline void vec3::make_unit_vector() {
    double k = 1.0 / sqrt(e[0] * e[0] + e[1] * e[1] + e[2] * e[2]);
    e[0] *= k;
    e[1] *= k;
    e[2] *= k;
}

inline vec3 operator+(const vec3 &v1, const vec3 &v2) {
    return vec3{v1.e[0] + v2.e[0],
                v1.e[1] + v2.e[1],
                v1.e[2] + v2.e[2]};
}

inline vec3 operator-(const vec3 &v1, const vec3 &v2) {
    return vec3{v1.e[0] - v2.e[0],
                v1.e[1] - v2.e[1],
                v1.e[2] - v2.e[2]};
}

inline vec3 operator*(const vec3 &v1, const vec3 &v2) {
    return vec3{v1.e[0] * v2.e[0],
                v1.e[1] * v2.e[1],
                v1.e[2] * v2.e[2]};
}

inline vec3 operator/(const vec3 &v1, const vec3 &v2) {
    return vec3{v1.e[0] / v2.e[0],
                v1.e[1] / v2.e[1],
                v1.e[2] / v2.e[2]};
}

inline vec3 operator*(double t, const vec3 &v1) {
    return vec3{t * v1.e[0],
                t * v1.e[1],
                t * v1.e[2]};
}

inline vec3 operator/(vec3 &v1, double t) {
    return vec3{v1.e[0] / t,
                v1.e[1] / t,
                v1.e[2] / t};
}

inline vec3 operator/(vec3 &&v1, double t) {
    return vec3{v1.e[0] / t,
                v1.e[1] / t,
                v1.e[2] / t};
}

inline vec3 operator*(const vec3 &v1, double t) {
    return t * v1;
}

inline double dot(const vec3 &v1, const vec3 &v2) {
    return v1.e[0] * v2.e[0]
           + v1.e[1] * v2.e[1]
           + v1.e[2] * v2.e[2];
}

inline vec3 cross(const vec3 &v1, const vec3 &v2) {
    return vec3{
            v1.e[1] * v2.e[2] - v1.e[2] * v2.e[1],
            -(v1.e[0] * v2.e[2] - v1.e[2] * v2.e[0]),
            v1.e[0] * v2.e[1] - v1.e[1] * v2.e[0]
    };
}

inline vec3& vec3::operator+=(const vec3 &v) {
    e[0] += v.e[0];
    e[1] += v.e[1];
    e[2] += v.e[2];
    return *this;
}

inline vec3& vec3::operator*=(const vec3 &v) {
    e[0] *= v.e[0];
    e[1] *= v.e[1];
    e[2] *= v.e[2];
    return *this;
}

inline vec3& vec3::operator/=(const vec3 &v) {
    e[0] /= v.e[0];
    e[1] /= v.e[1];
    e[2] /= v.e[2];
    return *this;
}

inline vec3& vec3::operator-=(const vec3 &v) {
    e[0] -= v.e[0];
    e[1] -= v.e[1];
    e[2] -= v.e[2];
    return *this;
}

inline vec3& vec3::operator*=(const double t) {
    e[0] *= t;
    e[1] *= t;
    e[2] *= t;
    return *this;
}

inline vec3& vec3::operator/=(const double t) {
    double k = 1.0/t;
    e[0] *= k;
    e[1] *= k;
    e[2] *= k;
    return *this;
}

inline vec3 unit_vector(vec3 v)
{
    return v / v.length();
}

#endif //RAY_TRACING_IN_A_WEEKEND_VEC3_H