Vector3的C++简单实现。

来自借来的图书3D数学基础：图形与游戏开发。记录一下。

#ifndef VECTOR3_H_INCLUDED#define VECTOR3_H_INCLUDEDclass Vector3{public:    float x,y,z;    Vector3() {}    Vector3(){const Vector3 &a} : x(a.x),y(a.y),z(a.z) {}    Vector3(float nx,float ny,float nz) : x(nx),y(ny),z(nz) {}    Vector3 &operator =(const Vector3 &a){        x = a.x;        y = a.y;        z = a.z;    }    bool operator ==(const Vector3 &a){        return x == a.x && y == a.y && z == a.z;    }    bool operator !=(const Vector3 &a){        return x != a.x || y != a.y || z != a.z;    }    void zero() {        x = y = z = 0.0f;    }    Vector3 operator - () const {    	return Vector3(-x,-y,-z);    }    Vector3 operator +(const Vector3 &a) const{    	return Vector3(x + a.x, y + a.y, z + a.z);    }    Vector3 operator -(const Vector3 &a) const{        return Vector3(x - a.x,y-a.y,z-a.z);    }    Vector3 operator *(float a ) const {    	return Vector3(x * a, y * a, z * a);    }    Vector3 operator /(float a) const {    	float oneOverA = 1.0f / a;    	return Vector3(x*oneOverA,y*oneOverA,z*oneOverA);    }    Vector3 &operator +=(const Vector3 &a){    	x += a.x;    	y += a.y;    	z += a.z;    	return *this;    }    Vector3 &operator -=(const Vector3 &a){    	x-= a.x;    	y-= a.y;    	z-= a.z;    	return *this;    }    Vector &operator *=(Vector3 &a){    	x *= a;    	y *= a;    	z *= a;    	return *this;    }    Vector3 &operator /=(float a){    	float oneOverA = 1.0f /a;    	x *= oneOverA；    	y *= oneOverA；    	z *= oneOverA；    	return *this;    }    void normalize(){    	float magSq = x*x + y*y + z*z;    	if(magSq > 0.0f){    		float oneOverMag = 1.0f/sqrt(magSq);    		x *= oneOverMag;    		y *= oneOverMag;    		z *= oneOverMag;    	}    }    float operator * (const Vector3 &a){    	return x * a.x + y * a.y + z * a.z;    }};inline float vectorMag(const Vector3 &a){	return sqrt(a.x * a.x , a.y * a.y, a.z * a.z);}inline Vector3 crossProduct(const Vector3 &a,const Vector3 &b){	return Vector3(		a.y * b.z - a.z * b.y,		a.z * b.x - a.x * b.z;		a.x * b.y - a.y * b.x;		)}inline Vector3 operator * (float k,const Vector &v){	return Vector3(k*v.x,k*v.y,k*v.z);}inline float distance(const Vector3 &a,const Vector &b){	float dx = a.x - b.x;	float dy = a.y - b.y;	float dz = a.z - b.z;	return sqrt(dx * dx,dy * dy,dz * dz);}extern const Vector3 kZeroVector;#endif // VECTOR3_H_INCLUDED