的Win32消息泵和std ::線程用於創建OpenGL上下文和渲染

Question

如果我有一個做以下的功能：

bool foo::init() 
{ 
    [Code that creates window] 
    std::thread run(std::bind(&foo::run, this)); 

    while (GetMessage(&msg, NULL, 0, 0)) { 
     TranslateMessage(&msg); 
     DispatchMessage(&msg); 
    } 
} 

其中行程被定義爲：

void foo::run() 
{ 
    [Code that creates initial opengl context] 
    [Code that recreates window based on new PixelFormat using wglChoosePixelFormatARB] 
    [Code that creates new opengl context using wglCreateContextAttribsARB] 

    do { 
     [Code that handles rendering] 
    } while (!terminate); 
} 

由於窗口在渲染線程上重新創建，並且消息泵將在主線程上執行，這被認爲是安全的？ WndProc會被調用什麼函數？上面的代碼可能被認爲是不好的設計，但這不是我所感興趣的。我只對定義的行爲感興趣。

Answer 1

Win32窗口綁定到創建它的線程。 只有那個線程可以接收和發送窗口的消息，而只有那個線程可以銷燬這個窗口。

因此，如果您在工作線程內重新創建窗口，那麼該線程必須接管管理窗口並分派其消息的責任。

否則，您需要將窗口的重新創建委託給主線程，以便它保留在最初創建它的同一個線程中。

bool foo::init() 
{ 
    [Code that creates window] 

    std::thread run(std::bind(&foo::run, this)); 

    while (GetMessage(&msg, NULL, 0, 0)) { 
     if (recreate needed) { 
      [Code that recreates window and signals worker thread] 
      continue; 
     } 
     TranslateMessage(&msg); 
     DispatchMessage(&msg); 
    } 
} 

void foo::run() 
{ 
    [Code that creates initial opengl context] 

    [Code that asks main thread to recreate window based on new PixelFormat using wglChoosePixelFormatARB, and waits for signal that the recreate is finished] 

    [Code that creates new opengl context using wglCreateContextAttribsARB] 

    do { 
     [Code that handles rendering] 
    } while (!terminate); 
} 

否則，調用在主線程wglChoosePixelFormatARB()開始工作線程之前，並存儲所選擇的PixelFormat其中線程可以訪問它。

bool foo::init() 
{ 
    [Code that creates window] 
    [Code that gets PixelFormat using wglChoosePixelFormatARB] 

    std::thread run(std::bind(&foo::run, this)); 

    while (GetMessage(&msg, NULL, 0, 0)) { 
     TranslateMessage(&msg); 
     DispatchMessage(&msg); 
    } 
} 

void foo::run() 
{ 
    [Code that creates opengl context using wglCreateContextAttribsARB] 

    do { 
     [Code that handles rendering] 
    } while (!terminate); 
}