vec3.h

#ifndef VEC3H
#define VEC3H

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

class vec3
{

  public:
	vec3() {}
	vec3(float e0, float e1, float e2)
	{
		e[0] = e0;
		e[1] = e1;
		e[2] = e2;
	}

	inline float x() const { return e[0]; }
	inline float y() const { return e[1]; }
	inline float z() const { return e[2]; }
	inline float r() const { return e[0]; }
	inline float g() const { return e[1]; }
	inline float 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 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]);
	}
	inline float squared_length() const
	{
		return e[0] * e[0] + e[1] * e[1] + e[2] * e[2];
	}
	inline void make_unit_vector();

	float e[3];
};

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()
{
	float 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*(float t, const vec3 &v)
{
	return vec3(t * v.e[0], t * v.e[1], t * v.e[2]);
}

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

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

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

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]);
}

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 float t)
{
	e[0] *= t;
	e[1] *= t;
	e[2] *= t;
	return *this;
}

inline vec3 &vec3::operator/=(const float t)
{
	float 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