BMP 的完整屏幕截图。 bliting 和保存的问题

Question

我想截取部分屏幕并将其保存为 BMP。为了保存图片，我计划使用 SOIL。我得到的位 bliting 函数 here.

代码：

bool saveScreen(string path)
{
    string name;
    SYSTEMTIME sm;
    GetSystemTime(&sm);
    name = to_string(sm.wHour) + to_string(sm.wMinute) + to_string(sm.wSecond) + to_string(sm.wMilliseconds) 
    + "_" + to_string(sm.wDay) + to_string(sm.wMonth) + to_string(sm.wYear);

    path = /*path + "/" +*/ name + ".bmp";
    const char *charPath = path.c_str();

    BITMAPINFO bmi;
    auto& hdr = bmi.bmiHeader;
    hdr.biSize = sizeof(bmi.bmiHeader);
    hdr.biWidth = screenWidth;
    hdr.biHeight = screenHeight;
    hdr.biPlanes = 1;
    hdr.biBitCount = 32;
    hdr.biCompression = BI_RGB;
    hdr.biSizeImage = 0;
    hdr.biXPelsPerMeter = 0;
    hdr.biYPelsPerMeter = 0;
    hdr.biClrUsed = 0;
    hdr.biClrImportant = 0;

    unsigned char* bitmapBits;
    HDC hdc = GetDC(NULL);
    HDC hBmpDc = CreateCompatibleDC(hdc);

    BITMAP bm;
    HBITMAP hBmp = CreateDIBSection(hdc, &bmi, DIB_RGB_COLORS, (void**)&bitmapBits, nullptr, 0);
    SelectObject(hBmpDc, hBmp);
    BitBlt(hBmpDc, 0, 0, screenWidth, 1024, hdc, 0, 0, SRCCOPY);

    vector< unsigned char > buf(screenWidth* screenHeight* 3);

    glPixelStorei(GL_PACK_ALIGNMENT, 1);
    glReadPixels(0, 0, screenWidth, screenHeight, GL_RGB, GL_UNSIGNED_BYTE, bitmapBits);

    int texture = SOIL_save_image(charPath, SOIL_SAVE_TYPE_BMP, screenWidth, screenHeight, 3, bitmapBits);

    return texture;
}

关于输出我得到这个：

Broken BMP

它看起来像 RGBA/RGB 问题，但我没有在任何地方设置 RGBA。我在代码中遗漏了什么？截图的正确方式是？

Answer 1

您创建了 32 bpp 图像，但是将 3 传递给 SOIL_save_image 表示它是 24 bpp 图像。

BMP 的完整屏幕截图。 bliting 和保存的问题

Full screenshot to BMP. Issue with bliting and saving

c++

opengl

winapi

soil