空间向量类Vector3的C++实现

浏览数：96 / 时间：2015年06月08日

提要

两年前的我写下了这篇文章 - 向量类的实现。现在看来，这代码真是略显丑陋。

于是，重新写吧。

参照了一下Unity3d 的Vector3类的接口。话不多说，上代码。

编译器：gcc 4.6.3

代码清单

vector3.h

#ifndef VECTOR3_H
#define VECTOR3_H

#include <math.h>
#include <assert.h>
#include <iostream>
#define PI 3.14159265
using namespace std;

class Vector3
{
    public:
        float x;
        float y;
        float z;
        Vector3();
        Vector3(float x, float y, float z);
        ~Vector3();
        bool HasNaNs() const;
        void set(float _x, float _y, float _z);

        //Static functions
        static Vector3 back();
        static Vector3 down();
        static Vector3 forward();
        static Vector3 left();
        static Vector3 one();
        static Vector3 right();
        static Vector3 up();
        static Vector3 zero();

        float magnitude() const;
        float sqrtMagnitude() const;
        Vector3 normalized();

        //Operators
        //Add two Vectors
        Vector3 operator+(const Vector3 &v) const;
        //Subtracts one vector from another
        Vector3 operator-(const Vector3 &v) const;
        Vector3 operator*(float num) const;
        Vector3 operator/(float num) const;
        Vector3 &operator+=(const Vector3 &v);
        Vector3 &operator-=(const Vector3 &v);
        Vector3 &operator*=(float num);
        Vector3 &operator/=(float num);
        //Returns true if vectors different.
        bool operator!=(Vector3 &v) const;

        friend std::ostream& operator<<(std::ostream& output,const Vector3& v)
        {
            output<<"("<<v.x<<","<<v.y<<","<<v.z<<")"<<"\n";
            return output;
        }

           //Static Functions
        //Calculate angle between two vectors.
        static float Angle(const Vector3 &from, const Vector3 &to)
        {
            double c, d;
            c = from.x*to.x + from.y*to.y + from.z*to.z;
            d = sqrt(from.x*from.x + from.y*from.y + from.z*from.z) * sqrt(to.x*to.x + to.y*to.y + to.z*to.z);
            return acos(c/d) * 180.0 / PI;
        }

        //Get dot result of two vector2.
        static inline float Dot(const Vector3 &v1, const Vector3 &v2)
        {
            return v1.x * v2.x + v1.y * v2.y + v1.z * v2.z;
        }

        //Get cross result of two vector2.
        static inline Vector3 Cross(const Vector3 &v1, const Vector3 &v2)
        {
            return Vector3((v1.y * v2.z) - (v1.z * v2.y),
                           (v1.z * v2.x) - (v1.x * v2.z),
                           (v1.x * v2.y) - (v1.y * v2.x));
        }
        //Get a normalized vector3 from a given vector3.
        static inline Vector3 Normalize(const Vector3 &v1)
        {
            float tmpLength = v1.magnitude();
            return Vector3(v1.x/tmpLength, v1.y/tmpLength, v1.z/tmpLength);
        }

        //Construct a coordinateSystem by a given vector3. v2 and v3 are output.
        static inline void CoordinateSystem(const Vector3 &v1, Vector3 *v2, Vector3 *v3)
        {
            if(fabsf(v1.x) > fabsf(v1.y))
            {
                float invLen = 1.0f / sqrtf(v1.x*v1.x + v1.z*v1.z);
                *v2 = Vector3(-v1.z * invLen, 0.0f, v1.x * invLen);
            }else
            {
                float invLen = 1.0f / sqrt(v1.y*v1.y + v1.z*v1.z);
                *v2 = Vector3(0.0f, v1.z * invLen, -v1.y * invLen);
            }
            *v3 = Vector3::Cross(v1, *v2);
        }

        static Vector3 ClampMagnitude();
        static Vector3 Lerp(const Vector3 &v1, const Vector3 &v2);
        static Vector3 OrthoNormalize();
    protected:
    private:


};

#endif // VECTOR3_H

vector3.cpp

#include "vector3.h"

Vector3::Vector3()
{
    x = y = z = 0.0f;
}

Vector3::Vector3(float _x, float _y, float _z):x(_x),y(_y),z(_z)
{
    assert(!HasNaNs());
}


Vector3::~Vector3()
{
    //dtor
}

bool Vector3::HasNaNs() const
{
    return isnan(x) || isnan(y) || isnan(z);
}

Vector3 Vector3::one()
{
    return Vector3(1, 1, 1);
}

float Vector3::magnitude() const
{

    return sqrt(x*x + y*y + z*z);

}

float Vector3::sqrtMagnitude() const
{
    return x*x + y*y + z*z;
}

void Vector3::set(float _x, float _y, float _z)
{
    x = _x;
    y = _y;
    z = _z;
}

Vector3 Vector3::operator+(const Vector3 &v) const
{
    return Vector3(x + v.x, y+ v.y, z+ v.z);
}

Vector3 Vector3::operator-(const Vector3 &v) const
{
    return Vector3(x - v.x, y - v.y, z - v.z);
}

Vector3 Vector3::operator*(float num) const
{
    return Vector3(num*x, num*y, num*z);
}

Vector3 Vector3::operator/(float num) const
{
    return Vector3(x/num, y/num, z/num);
}

Vector3& Vector3::operator*=(float num)
{
    x *= num; y *= num; z *= num;
    return *this;
}

Vector3& Vector3::operator/=(float num)
{
    x /= num; y /= num; z /= num;
    return *this;
}

Vector3& Vector3::operator+=(const Vector3 &v)
{
    x += v.x; y += v.y; z += v.z;
    return *this;
}

Vector3& Vector3::operator-=(const Vector3 &v)
{
    x -= v.x; y -= v.y; z -= v.z;
    return *this;
}

bool Vector3::operator!=(Vector3 &v) const
{
    return x==v.x && y==v.y && z==v.z;
}


Vector3 Vector3::normalized()
{
    float tmpLength = this->magnitude();
    return Vector3(x/tmpLength, y/tmpLength, z/tmpLength);
}

测试代码

#include <iostream>
#include "vector3.h"

using namespace std;

int main()
{
    Vector3 v1,v2,v3;
    v1=Vector3(1.0,-1.0,0.0);
    v2=Vector3(-1.0,-1.0,0.0);
    cout<<"v1: "<<v1<<endl;
    v2=v2/2;
    cout<<"v2: "<<v2<<endl;
    cout<<"Angle: "<<Vector3::Angle(v1, v2)<<endl;
    v3=Vector3::Cross(v1,v2);
    float a=Vector3::Dot(v1,v2);
    cout<<"v1 dotMul v2:"<<a<<endl;
    cout<<"v3.Length:"<<v3.magnitude()<<endl;
    Vector3 v4 = v3.normalized();
    cout<<"v3 After nomarlize:"<<v4<<endl;
    return 0;
}

运行结果