Vector3.h

// Copyright 2021 SMS
// License(Apache-2.0)

#pragma once

#include <cfloat>
#include <cmath>

class Vector3
{
public:
    float x = 0.0f;
    float y = 0.0f;
    float z = 0.0f;

    Vector3() = default;

    Vector3(float x, float y, float z);

    float size() const;

    float sizeSquared() const;

    float distance(const Vector3& point) const;

    float distanceSquared(const Vector3& point) const;

    Vector3& normalize();

    float dot(const Vector3& v) const;

    float angle() const;

    void rotate(const Vector3& point, float angle);

    Vector3 getMidPoint(const Vector3& p) const;

    float&   operator[](size_t index);
    bool     operator==(const Vector3& v) const;
    bool     operator!=(const Vector3& v) const;
    Vector3  operator*(float n) const;
    Vector3  operator/(float n) const;
    Vector3  operator+(const Vector3& v) const;
    Vector3  operator-(const Vector3& v) const;
    Vector3  operator-() const;
    Vector3& operator+=(const Vector3& v);
    Vector3& operator-=(const Vector3& v);
    Vector3& operator*=(float n);
    Vector3& operator/=(float n);

    static const Vector3 unit; // (1, 1, 1)
    static const Vector3 zero; // (0, 0, 0)

    static const Vector3 up;    // (0, 1, 0)
    static const Vector3 down;  // (0, -1, 0)
    static const Vector3 right; // (-1, 0, 0)
    static const Vector3 left;  // (1, 0, 0)
    static const Vector3 front; // (0, 0, -1)
    static const Vector3 back;  // (0, 0, 1)
};

using Point3 = Vector3; // TODO: 使用齐次坐标时, w 不等于 0 时, 点的坐标为 (x/w, y/w, z/w).
using Vec3   = Vector3;