vector2.h

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// Copyright © 2008-2021 Pioneer Developers. See AUTHORS.txt for details
// Licensed under the terms of the GPL v3. See licenses/GPL-3.txt
 
#pragma once
 
#ifndef _VECTOR2_H
#define _VECTOR2_H
 
#include "FloatComparison.h"
#include <math.h>
 
template <typename T>
struct other_floating_type {};
template <>
struct other_floating_type<float> {
    typedef double type;
};
template <>
struct other_floating_type<double> {
    typedef float type;
};
 
template <typename T>
class vector2 {
public:
    T x, y;
 
    vector2() :
        x(0.0f),
        y(0.0f) {}
    vector2(T _x, T _y) :
        x(_x),
        y(_y) {}
    explicit vector2(int v) :
        x(T(v)),
        y(T(v)) {}
    explicit vector2(unsigned int v) :
        x(T(v)),
        y(T(v)) {}
    explicit vector2(T v) :
        x(v),
        y(v) {}
    explicit vector2(const T v[2]) :
        x(v[0]),
        y(v[1]) {}
 
    // disallow implicit conversion between floating point sizes
    explicit vector2(const vector2<typename other_floating_type<T>::type> &v);
    explicit vector2(const typename other_floating_type<T>::type vals[2]);
 
    vector2 operator+(const vector2 &v) const { return vector2(x + v.x, y + v.y); }
    vector2 operator-(const vector2 &v) const { return vector2(x - v.x, y - v.y); }
    vector2 &operator+=(const vector2 &v)
    {
        x += v.x;
        y += v.y;
        return *this;
    }
    vector2 &operator-=(const vector2 &v)
    {
        x -= v.x;
        y -= v.y;
        return *this;
    }
    vector2 &operator*=(const T &a)
    {
        x *= a;
        y *= a;
        return *this;
    }
    vector2 operator-() const { return vector2(-x, -y); }
 
    bool operator==(const vector2 &a) const
    {
        return is_equal_exact(a.x, x) && is_equal_exact(a.y, y);
    }
    bool ExactlyEqual(const vector2 &a) const
    {
        return is_equal_exact(a.x, x) && is_equal_exact(a.y, y);
    }
 
    friend vector2 operator*(const vector2 &v, const T &a) { return vector2(v.x * a, v.y * a); }
    friend vector2 operator*(const T &a, const vector2 &v) { return v * a; }
    friend vector2 operator*(const vector2 &va, const vector2 &vb) { return vector2(va.x * vb.x, va.y * vb.y); }
    friend vector2 operator/(const vector2 &v, const T &a) { return vector2(v.x / a, v.y / a); }
    friend bool operator<(const vector2 &va, const vector2 &vb) { return va.LengthSqr() < vb.LengthSqr(); }
 
    T Length() const { return sqrt(x * x + y * y); }
    T LengthSqr() const { return x * x + y * y; }
    vector2 Normalized() const
    {
        const T invlen = 1.0f / sqrt(x * x + y * y);
        return vector2(x * invlen, y * invlen);
    }
    vector2 NormalizedSafe() const
    {
        const T lenSqr = x * x + y * y;
        if (lenSqr < 1e-18) // sqrt(lenSqr) < 1e-9
            return vector2(1, 0);
        else {
            const T invlen = sqrt(lenSqr);
            return vector2(x / invlen, y / invlen);
        }
    }
    vector2 Rotate(T alpha) // Rotate around center
    {
        return vector2(x * cos(alpha) - y * sin(alpha), y * cos(alpha) + x * sin(alpha));
    }
 
    void Print() const { printf("v(%f,%f)\n", x, y); }
};
 
template <>
inline vector2<float>::vector2() {}
template <>
inline vector2<double>::vector2() {}
template <>
inline vector2<float>::vector2(const vector2<double> &v) :
    x(float(v.x)),
    y(float(v.y)) {}
template <>
inline vector2<double>::vector2(const vector2<float> &v) :
    x(v.x),
    y(v.y) {}
 
typedef vector2<float> vector2f;
typedef vector2<double> vector2d;
 
#endif