#ifndef GEOMETRY_H

#define GEOMETRY_H

#include <cmath></cmath>

typedef double Real;

class Vector2 {

public:

    union {

        struct { Real x, y; };

        struct { Real c[2]; };

    };

    explicit Vector2(Real x = 0, Real y = 0):

        x(x), y(y) { }

    Real len_sqr() const { return x*x + y*y; }

    Real len() const { return sqrt(len_sqr()); }

};

class Vector3 {

public:

    union {

        struct { Real x, y, z; };

        struct { Real r, g, b; };

        struct { Real c[3]; };

    };

    explicit Vector3(Real x = 0, Real y = 0, Real z = 0):

        x(x), y(y), z(z) { }

    Vector3 operator+(const Vector3 &v) const

        { return Vector3(x+v.x, y+v.y, z+v.z); }

    Vector3 operator-(const Vector3 &v) const

        { return Vector3(x-v.x, y-v.y, z-v.z); }

    Real operator*(const Vector3 &v) const

        { return x*v.x + y*v.y + z*v.z; }

    Vector3 operator*(Real k) const

        { return Vector3(x*k, y*k, z*k); }

    Vector3 cross(const Vector3 &v) const

        { return Vector3(y*v.z - z*v.y, z*v.x - x*v.z, x*v.y - y*v.x); }

    Real len_sqr() const { return x*x + y*y + z*z; }

    Real len() const { return sqrt(len_sqr()); }

};

class Vector4 {

public:

    union {

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

        struct { Real r, g, b, a; };

        struct { Real c[4]; };

    };

    explicit Vector4(Real x = 0, Real y = 0, Real z = 0, Real w = 0):

        x(x), y(y), z(z), w(w) { }

};

#endif