snoopy/src/vec3.h

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2020-06-01 02:49:50 +02:00
#pragma once
#include <cmath>
#include <iostream>
class vec3
{
public:
vec3() : e{0,0,0} {}
vec3(double e0, double e1, double e2) : e{e0, e1, e2} {}
double x() const { return e[0]; }
double y() const { return e[1]; }
double z() const { return e[2]; }
vec3 operator-() const { return vec3(-e[0], -e[1], -e[2]); }
double operator[](int i) const { return e[i]; }
double& operator[](int i) { return e[i]; }
vec3& operator+=(const vec3 &v)
{
e[0] += v.e[0];
e[1] += v.e[1];
e[2] += v.e[2];
return *this;
}
vec3& operator*=(const double t)
{
e[0] *= t;
e[1] *= t;
e[2] *= t;
return *this;
}
vec3& operator/=(const double t)
{
return *this *= 1 / t;
}
double length() const
{
return std::sqrt(lengthSquared());
}
double lengthSquared() const
{
return e[0]*e[0] + e[1]*e[1] + e[2]*e[2];
}
public:
double e[3];
};
// type aliases for vec3
using point3 = vec3; // 3D point
using colour = vec3; // RGB colour
// utility functions
inline std::ostream& operator<<(std::ostream &out, const vec3 &v)
{
return out << v.e[0] << ' ' << v.e[1] << ' ' << v.e[2];
}
inline vec3 operator+(const vec3 &u, const vec3 &v)
{
return vec3(u.e[0] + v.e[0], u.e[1] + v.e[1], u.e[2] + v.e[2]);
}
inline vec3 operator-(const vec3 &u, const vec3 &v)
{
return vec3(u.e[0] - v.e[0], u.e[1] - v.e[1], u.e[2] - v.e[2]);
}
inline vec3 operator*(const vec3 &u, const vec3 &v)
{
return vec3(u.e[0] * v.e[0], u.e[1] * v.e[1], u.e[2] * v.e[2]);
}
inline vec3 operator*(double t, const vec3 &v)
{
return vec3(t * v.e[0], t * v.e[1], t * v.e[2]);
}
inline vec3 operator*(const vec3 &v, double t)
{
return t * v;
}
inline vec3 operator/(vec3 v, double t)
{
return (1 / t) * v;
}
inline double dot(const vec3 &u, const vec3 &v)
{
return u.e[0] * v.e[0]
+ u.e[1] * v.e[1]
+ u.e[2] * v.e[2];
}
inline vec3 cross(const vec3 &u, const vec3 &v)
{
return vec3(u.e[1] * v.e[2] - u.e[2] * v.e[1],
u.e[2] * v.e[0] - u.e[0] * v.e[2],
u.e[0] * v.e[1] - u.e[1] * v.e[0]);
}
inline vec3 unitVector(vec3 v)
{
return v / v.length();
}