先添加一个普通类，

Vector3.h，

// Vector3.h: interface for the Vector3 class.
//
//

#if !defined(AFX_VECTOR3_H__53D34D26_95FF_4377_BD54_57F4271918A4__INCLUDED_)
#define AFX_VECTOR3_H__53D34D26_95FF_4377_BD54_57F4271918A4__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#include <cmath>
 
class Vector3 {
public:
    float x, y, z;
 
    // 构造函数
    Vector3() : x(0.0f), y(0.0f), z(0.0f) {}
    Vector3(float x, float y, float z) : x(x), y(y), z(z) {}
 
    // 访问器
    float getX() const { return x; }
    float getY() const { return y; }
    float getZ() const { return z; }
 
    // 修改