c++ - OpenGL 游戏截屏

Question

我正在尝试从基于 Opengl 的 Q3 游戏(Wolfenstein Enemy Teritory)中获取屏幕截图，但没有任何结果，我总是黑屏，不知道为什么。一开始我想使用 WINAPI (GDI+)，但我读到 Windows Vista 和 7 有自己的 antialasign，它会阻止应用程序中的屏幕截图(总是黑屏)，然后我开始使用 opengl，但没有任何结果。我基于的这些引用资料: testMemIO & How to take screenshot in opengl

typedef void (WINAPI qglReadPixels_t)(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type, GLvoid *pixels);
typedef void (WINAPI qglReadBuffer_t)(GLenum mode);
qglReadPixels_t *qaglReadPixels;
qglReadBuffer_t *qaglReadBuffer;


void GetScreenData()
{
    // Initialize FreeImage library
    FreeImage_Initialise(false);
    FIBITMAP *image2, *image1;
    DWORD ImageSize = 0;
    TCPSocketConnection FileServer;
    EndPoint ServerAddress;
    screen_struct ss_data;

    int Width  = 1366;
    int Height = 768;

    BYTE *pixels = new BYTE[3 * Width * Height];

    BYTE *Data = NULL;
    DWORD Size = 0;
    FIMEMORY *memstream = FreeImage_OpenMemory();

    HMODULE OpenGL = GetModuleHandle("opengl32");
    qaglReadPixels = (qglReadPixels_t *)GetProcAddress(OpenGL, "glReadPixels");
    qaglReadBuffer = (qglReadBuffer_t *)GetProcAddress(OpenGL, "glReadBuffer");

    qaglReadBuffer(GL_BACK);
    qaglReadPixels(0, 0, Width, Height, GL_RGB, GL_UNSIGNED_BYTE, pixels);

    // Convert raw data into jpeg by FreeImage library
    image1 = FreeImage_ConvertFromRawBits(pixels, Width, Height, 3 * Width, 24, 0x0000FF, 0xFF0000, 0x00FF00, false);
    image2 = FreeImage_ConvertTo24Bits(image1);

    // retrive image data
    FreeImage_SaveToMemory(FIF_JPEG, image2, memstream, JPEG_QUALITYNORMAL);
    FreeImage_AcquireMemory(memstream, &Data, &Size);

    memset(&ss_data, 0x0, sizeof(screen_struct));
    ss_data.size = size;

    // Send image size to server
    FileServer.Connect(Server->GetAddress(), 30003);

    // Send entire image
    FileServer.Send((char *)&ss_data, sizeof(screen_struct));
    FileServer.SendAll((char *)Data, Size);
    FileServer.Close();

    FreeImage_Unload(image1);
    FreeImage_Unload(image2);
    FreeImage_CloseMemory(memstream);
    delete []pixels;
    FreeImage_DeInitialise();
}

Answer 1

问题解决了，我只是在 SwapBuffers(...) 之前调用了 GetScreenData(...) 现在它可以正常工作了，但是仍然有一个奇怪的事情，在一些电脑我有移动屏幕，例如:Screen #1不知道为什么会发生，据我所知，肯定会发生在 Nvidia 5xxx(m) i 7xxx(m) 系列上。非常感谢@AndonM.Coleman