vec3.h

#ifndef VEC3_H
#define VEC3_H

#include <math.h>
#include <stdlib.h>
#include <iostream>
#include <stdio.h>
#include <thread>

//
// This is a standard implementation of 3D vectors. Adopted from textbook *Ray tracing in one weekend*
//

class vec3 {
public:
    vec3() {}

    vec3(float e0, float e1, float e2) {
        e[0] = e0;
        e[1] = e1;
        e[2] = e2;
    } //constructor (x,y,z)

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

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

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

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

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

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

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

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

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

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

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

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

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

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


    float e[3];
};


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

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

//overload operator plus
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]);
}

//overload operator minus
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]);
}

//overload operator multiply (vector multiplication)
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]);
}

//overload operator divide (vector division)
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]);
}

//overload operator multiply (scalar multiplication)
inline vec3 operator*(float t, const vec3 &v) {
    return vec3(t * v.e[0], t * v.e[1], t * v.e[2]);
}

//overload operator divide (scalar division)
inline vec3 operator/(vec3 v, float t) {
    return vec3(v.e[0] / t, v.e[1] / t, v.e[2] / t);
}

//overload operator multiply (scalar multiplication)
inline vec3 operator*(const vec3 &v, float t) {
    return vec3(t * v.e[0], t * v.e[1], t * v.e[2]);
}


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

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

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

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

//overload operator multiply-assign (scalar multiplication)
inline vec3 &vec3::operator*=(const float t) {
    e[0] *= t;
    e[1] *= t;
    e[2] *= t;
    return *this;
}

//overload operator divide-assign (scalar division)
inline vec3 &vec3::operator/=(const float t) {
    float k = 1.0 / t;

    e[0] *= k;
    e[1] *= k;
    e[2] *= k;
    return *this;
}

//compute dot product on two vectors
inline float 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];
}

//compute cross product on two vectors
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]));
}

//compute the unit vector in the direction of that vector
inline vec3 unit_vector(vec3 v) {
    return v / v.length();
}


#endif //VEC3_H