爲什麼複製時調用析構函數？

Question

我有一個嚴重的問題，我使用默認的構造函數來初始化對象和一個帶參數的構造函數來複制DirectX接口。

SpriteBatch spriteBatch; //Creating an Object to SpriteBatch Class 

//This Function Gets Called when Device is Created with Parameter to Device 
void LoadContent(GraphicDevice graphicDevice) 
{ 
    /*Here is the Problem, When it Assigns to the Object it creates a Temp Object and 
    Destructor gets called where I free everything, I can't use the GraphicDevice after 
    this.*/ 

    spriteBatch = SpriteBatch(graphicDevice); 
} 


//SpriteBatch Class 

class SpriteBatch 
{ 
    GraphicDevice graphicDevice; 

    public: 
    SpriteBatch(); 
    SpriteBatch(GraphicDevice graphicDevice); 
    ~SpriteBatch(); 
} 

SpriteBatch::SpriteBatch() 
{ 
} 

SpriteBatch::SpriteBatch(GraphicDevice graphicDevice) 
{ 
    this->graphicDevice = graphicDevice; 
} 

SpriteBatch::~SpriteBatch() 
{ 
    graphicDevice-Release(); 
} 

我希望在程序結束時調用析構函數，而不是在複製兩個對象時調用析構函數。 我試圖重載賦值運算符和複製構造函數，但沒有幫助我。 有沒有辦法做到這一點？

Answer 1

通過引用傳遞，減少拷貝，臨時對象的數量和他們的破壞：

void LoadContent(GraphicDevice& graphicDevice) 
{ 
    spriteBatch = SpriteBatch(graphicDevice); 
} 

然後：

SpriteBatch::SpriteBatch(GraphicDevice& graphicDevice) 
    :graphicDevice(graphicDevice) 
{ 
} 

如果你想避免新GraphicDevice爲SpriteBatch每個實例，製作GraphicDevice graphicDevice;作爲參考：

GraphicDevice& graphicDevice; 

這將需要在所有SpriteBatch構造函數中初始化。

Answer 2

對graphicDevice使用shared_ptr，以便僅當引用計數達到零時纔會釋放它。你不應該在析構函數中首先處理這個問題。