[C++][代码库]Vector3空间向量类

本文用C++实现一个简单的Vector3类的功能，暂时有的功能是：

1 + - * /算术运算

2 向量的数量积，又叫：点乘

3 向量的向量积，又叫：叉乘

4 向量单位化（normalization)

//Vecotr3.h
#pragma once  

extern const double uZero;  

class Vector3
{
    float x, y, z;
public:
    Vector3():x(0), y(0), z(0){}
    Vector3(float x1, float y1, float z1):x(x1), y(y1), z(z1){}
    Vector3(const Vector3 &v);
    ~Vector3();
    void operator=(const Vector3 &v);
    Vector3 operator+(const Vector3 &v);
    Vector3 operator-(const Vector3 &v);
    Vector3 operator/(const Vector3 &v);
    Vector3 operator*(const Vector3 &v);
    Vector3 operator+(float f);
    Vector3 operator-(float f);
    Vector3 operator/(float f);
    Vector3 operator*(float f);
    float dot(const Vector3 &v);
    float length();
    void normalize();
    Vector3 crossProduct(const Vector3 &v);
    void printVec3();
};  

//Vector3.cpp
#include"Plane.h"
#include<iostream>  

const double uZero = 1e-6;  

//复制构造函数，必须为常量引用参数，否则编译不通过
Vector3::Vector3(const Vector3 &v):x(v.x), y(v.y), z(v.z)
{
}  

Vector3::~Vector3()
{
}  

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

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

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

Vector3 Vector3::operator/(const Vector3 &v)
{
    if (fabsf(v.x) <= uZero || fabsf(v.y) <= uZero || fabsf(v.z) <= uZero)
    {
        std::cerr<<"Over flow!\n";
        return *this;
    }
    return Vector3(x/v.x, y/v.y, z/v.z);
}  

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

Vector3 Vector3::operator+(float f)
{
    return Vector3(x+f, y+f, z+f);
}  

Vector3 Vector3::operator-(float f)
{
    return Vector3(x-f, y-f, z-f);
}  

Vector3 Vector3::operator/(float f)
{
    if (fabsf(f) < uZero)
    {
        std::cerr<<"Over flow!\n";
        return *this;
    }
    return Vector3(x/f, y/f, z/f);
}  

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

float Vector3::dot(const Vector3 &v)
{
    return x*v.x + y*v.y + z*v.z;
}  

float Vector3::length()
{
    return sqrtf(dot(*this));
}  

void Vector3::normalize()
{
    float len = length();
    if (len < uZero) len = 1;
    len = 1/len;  

    x *= len;
    y *= len;
    z *= len;
}  

/*
Cross Product叉乘公式
aXb = | i,  j,  k  |
     | a.x a.y a.z|
     | b.x b.y b.z| = (a.x*b.z -a.z*b.y)i + (a.z*b.x - a.x*b.z)j + (a.x+b.y - a.y*b.x)k
*/
Vector3 Vector3::crossProduct(const Vector3 &v)
{
    return Vector3(y * v.z - z * v.y,
                z * v.x - x * v.z,
                x * v.y - y * v.x);
}  

void Vector3::printVec3()
{
    std::cout<<"("<<x<<", "<<y<<", "<<z<<")"<<std::endl;
}  

测试主程序：

#include<iostream>
#include<vector>
#include"Vector3.h"  

using namespace std;  

int main()
{
    Vector3 v31;
    Vector3 v32(2.0f,3.0f,4.0f);
    Vector3 v33(v32 - 1.0f);
    cout<<"We have original Vector3s:\n";
    v31.printVec3();
    v32.printVec3();
    v33.printVec3();  

    cout<<"v32 crossproduct v33 is:\n";
    Vector3 v3233 = v32.crossProduct(v33);
    v3233.printVec3();  

    cout<<"Now we normalize them:\n";
    v31.normalize();
    v32.normalize();
    v33.normalize();
    v3233.normalize();
    v31.printVec3();
    v32.printVec3();
    v33.printVec3();
    v3233.printVec3();  

    system("pause");
    return 0;
}  

运算结果：