https://stackoverflow.com/posts/70620450

class Something {
private:
    // Console window, console stream handles.
    HDC    cwd;
    HANDLE chd;
    HWND   cwn;

    // ... //

    // Rendering
    uint32_t* frontBuf;
    uint32_t* backBuf;
    size_t    gbufSize;

    // ... //

public:
    // ... //

    // Intiailizes/prepares the application.
    void Initialize() {
        // get handles
        cwd = GetDC(GetConsoleWindow());
        chd = GetStdHandle(STD_OUTPUT_HANDLE);
        cwn = GetConsoleWindow();

        // prepare for rendering
        gbufSize = sizeof(uint32_t) * w * h;
        backBuf  = (uint32_t*)malloc(gbufSize);
        frontBuf = (uint32_t*)malloc(gbufSize);

        // ... //
    }

    // ... //

    // Swaps front and back buffers and
    // displays the new front buffer on the screen.
    void GSwap() {
        // swap pointers
        uint32_t* frontTmp = frontBuf;
        frontBuf = backBuf;
        backBuf = frontTmp;

        // clear new back buffer
        memset(backBuf, 0, gbufSize);

        // draw on screen
        /* ??? */
    }

    size_t GFlatten(int x, int y) {
        return y * h + x;
    }

    void GSetPixel(int x, int y, uint32_t color) {
        backBuf[GFlatten(x, y)] = color;
    }

    void GFillRect(int x, int y, int w, int h, uint32_t color) {
        for (int ix = x; ix < x + w; ix++) {
            for (int iy = y; iy < y + h; iy++) {
                GSetPixel(ix, iy, color);
            }
        }
    }

    void GFillScreen(uint32_t color) {
        memset(backBuf, color, gbufSize);
    }

};