第六章3D介面類

這本書的第六章主要寫了一個工具類,用作之前所描述的概念中向量的計算還有一些運算子的過載,是用C++寫的。

因經驗等原因.我對程式碼設計方面還不是很瞭解，也沒有系統學習過C++,,總之先貼出本書章節中的C++程式碼。

#include<math.h>


class Vector3 {
public:
	float x, y, z;
	//建構函式
	//預設建構函式,不執行任何操作
	Vector3() {}
	//複製建構函式
	Vector3(const Vector3 &a) : x(a.x), y(a.y), z(a.z){}
	//帶引數的建構函式,用三個值完成初始化
	Vector3(float nx, float ny, float nz) :x(nx), y(ny), z(nz){}
	//標準物件操作
	//堅持C語言的習慣,過載賦值運算子,並返回引用,以實現左值。
	Vector3 &operator = (const Vector3 &a){
		x = a.x; y = a.y; z = a.z;
		return *this;
	}

	// 過載 "" == "" 操作符
	bool operator == (const Vector3 &a) const{
		return x == a.x && y == a.y && z == a.z;
	}
	bool operator != (const Vector3 &a) const{
		return x != a.x || y != a.y || z != a.z;
	}
	//向量運算
	//置為零向量
	void zero() { x = y = z = 0.0f; };
	//過載一元"-"運算子
	Vector3 operator - () const { return Vector3(-x, -y, -z); };
	//過載二元 "+" 和 "-" 運算子
	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);
	}
	//與標量的乘、除法
	Vector3 operator *(float a) const{
		return Vector3(x * a, y * a, z * a);
	}

	Vector3 operator /(float a) const{
		float oneOverA = 1.0f / a; //注意:這裡不對"除零"進行檢查
		return Vector3(x * oneOverA, y * oneOverA, z *oneOverA);
	}
	//過載自反運算子
	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;
	}
	Vector3 &operator *= (float 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;
	}
	//向量標準化
	void normalize(){
		float magSq = x * x + y * y + z * z;
		if (magSq > 0.0f){ //檢查除零
			float oneOverMag = 1.0f / sqrt(magSq);
			x *= oneOverMag;
			y *= oneOverMag;
			z *= oneOverMag;
		}
	}
	//向量點乘,過載標準的乘法運算子
	float operator * (const Vector3 &a) const {
		return x * a.x + y * a.y + z * a.z;
	}
};
//
//非成員變數
//


//求向量模

inline float vectorMag(const Vector3 &a){
	return sqrt(a.x * a.x + a.y * a.y + a.z * a.z);
}
//向量叉乘
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
};
}

//實現標量左值
inline Vector3 operator *(float k, const Vector3 &v){
	return Vector3(k*v.x, k*v.y, k*v.z);
}
//計算兩次間的距離
inline float distance(const Vector3 &a, const Vector3 &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);
}
//全域性變數

//提供一個全域性零向量
extern const Vector3 kZeroVector;

float vectorMag(const Vector3 &a);
 

感謝vs的類圖功能，讓我省去了畫類圖的時間。

下面本人由於Unity的關係對於C#還是比較熟悉的，想把這段 改成C#形式後用。

class Vector3D
{
    public float x, y, z;
    //建構函式
    //預設建構函式,不執行任何操作
    Vector3D() { }
    //複製建構函式
    Vector3D(Vector3D a)
    {
        this.x = a.x;
        this.y = a.y;
        this.z = a.z;
    }
    //帶引數的建構函式,用三個值完成初始化
    Vector3D(float nx, float ny, float nz)
    {
        this.x = nx;
        this.y = ny;
        this.z = nz;
    }
    //標準物件操作
    //堅持C語言的習慣,過載賦值運算子,並返回引用,以實現左值。
    //!---C#不支援過載“=“運算子---!//
    // 過載 "" == "" 操作符
    public static bool operator ==(Vector3D a, Vector3D b)
    {
        return b.x == a.x && b.y == a.y && b.z == a.z;
    }
    // 過載 "" != "" 操作符
    public static bool operator !=(Vector3D a, Vector3D b)
    {
        return b.x != a.x || b.y != a.y || b.z != a.z;
    }
    //向量運算
    //置為零向量
    void zero() { x = y = z = 0.0f; }
    //過載一元"-"運算子
    Vector3D operator +(Vector3D a, Vector3D b)
    {
        return new Vector3D(a.x + b.x, a.y + a.y, a.z + b.z);
    }
    Vector3D operator -(Vector3D a, Vector3D b)
    {
        return new Vector3D(b.x - a.x, b.y - a.y, b.z - a.z);
    }
    //與標量的乘、除法
    Vector3D operator *(float a, Vector3D b)
    {
        return new Vector3D(b.x * a, b.y * a, b.z * a);
    }

    Vector3D operator /(float a, Vector3D b)
    {
        float oneOverA = 1.0f / a; //注意:這裡不對"除零"進行檢查
        return new Vector3D(b.x * oneOverA, b.y * oneOverA, b.z * oneOverA);
    }

    //C#不能顯示過載*=，+=，-=，、=自反運算子，已經嵌入在了一元運算子之中

    ////向量標準化
    void normalize()
    {
        float magSq = x * x + y * y + z * z;
        if (magSq > 0.0f)
        { //檢查除零
            float oneOverMag = (float)(1.0f / System.Math.Sqrt(magSq));
            x *= oneOverMag;
            y *= oneOverMag;
            z *= oneOverMag;
        }
    }
    //向量點乘,過載標準的乘法運算子
    float operator *(Vector3D a, Vector3D b)
    {
        return b.x * a.x + b.y * a.y + b.z * a.z;
    }
  public const Vector3D kZeroVector = new Vector3D();
}