How to convert screenshot to uint8_t array - c++

Question

I'm trying to somehow get screenshot from uint8 array of RGB, but for example this code doesn't work:
#include <torch/torch.h>
#include <iostream>
#include <Windows.h>
#include <gdiplus.h>
#include <gdipluspixelformats.h> // PixelFormat24bppRGB
#include <vector>
#include <cstdlib>
#pragma comment(lib, "gdiplus.lib")
int main()
{
Gdiplus::GdiplusStartupInput input;
ULONG_PTR token;
Gdiplus::GdiplusStartup(&token, &input, NULL);
const int mWidth = 1920;
const int mHeight = 1080;
std::vector<uint8_t> pixels;
Gdiplus::BitmapData bmpData;
DWORD start = GetTickCount64();
HDC hdcScreen = GetDC(NULL);
BITMAPINFO bmpInfo;
bmpInfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
bmpInfo.bmiHeader.biWidth = mWidth;
bmpInfo.bmiHeader.biHeight = mHeight;
bmpInfo.bmiHeader.biPlanes = 1;
bmpInfo.bmiHeader.biBitCount = 24;
bmpInfo.bmiHeader.biCompression = BI_RGB;
HDC scComDC = CreateCompatibleDC(hdcScreen);
BitBlt(
scComDC,
0,0,
mWidth,
mHeight,
hdcScreen,
0,0,
SRCCOPY
);
LPDWORD lpPixel;
HBITMAP display = CreateDIBSection(scComDC, &bmpInfo, DIB_RGB_COLORS, (void**)&lpPixel, NULL, 0);
ReleaseDC(NULL,hdcScreen);
DeleteDC(scComDC);
LOGPALETTE lpPalette;
lpPalette.palVersion = 0x0300;
lpPalette.palNumEntries = 1;
lpPalette.palPalEntry[0].peRed =
lpPalette.palPalEntry[0].peGreen =
lpPalette.palPalEntry[0].peBlue =
lpPalette.palPalEntry[0].peFlags = NULL;
HPALETTE hPalette = CreatePalette(&lpPalette);
auto image = Gdiplus::Bitmap::FromHBITMAP(display, hPalette);
int bWidth = image->GetWidth();
int bHeight = image->GetHeight();
std::cout << image << std::endl;
std::cout << bWidth << std::endl;
std::cout << bHeight << std::endl;
auto stride = 3 * bWidth;
pixels.resize(stride * bHeight);
Gdiplus::Rect rect(0, 0, bWidth, bHeight);
image->LockBits(&rect, Gdiplus::ImageLockModeRead, PixelFormat24bppRGB, &bmpData);
for (int y = 0; y < bHeight; ++y) {
memcpy(pixels.data() + y * stride, (byte*)bmpData.Scan0 + y * bmpData.Stride, stride);
}
image->UnlockBits(&bmpData);
DWORD end = GetTickCount64();
std::cout << end - start << "ms\n";
while (true){
int inint;
std::cin >> inint;
if (inint == -1) {
break;
}
std::cout << ">> " << +pixels[inint*3]
<< "," << +pixels[inint * 3 + 1]
<< "," << +pixels[inint * 3 + 2]
<< "\n";
}
Gdiplus::GdiplusShutdown(token);
//system("PAUSE");
return 1;
}
I cannot successfully convert pixels to vector by running this program. It returns 0,0,0 indicating that all pixels are black.
I think I'm right around memcpy, since I was able to array successfully with
auto image = Gdiplus::Bitmap::FromFile(L"C:\sample.jpg");
but when I use Bitmap::FromHBITMAP(display, hPalette);, it doesn't work at all.
get screenshot from uint8 array of RGB