FWcore::window::window(int _width, int _height, int _bpp, bool _fullscr){   // window creator class constructor
    // todo: make allow to create more window, with custom callback proc (for develop)
    width       = _width;
    height      = _height;
    fullscreen  =_fullscr;
    bpp         =_bpp;

    for (int i=0; i<256; i++) keys[i]=false;    // reset keys

    WNDCLASS wc = {
        CS_VREDRAW |CS_HREDRAW | CS_OWNDC,
        mainloopCallbackProc,   // <- custoimize
        0, 0,
        GetModuleHandle(0),
        static_cast<HICON>( LoadImage(GetModuleHandle( 0 ),
            MAKEINTRESOURCE(IDI_ICON1),
            IMAGE_ICON, 32, 32,
            LR_DEFAULTSIZE)),
        0,  0,  0,
        "WINCLASS" };   // <- customize

    if( !RegisterClass(&wc) ){
        MessageBox (HWND_DESKTOP, "Cannot register window class.", "Error", MB_OK | MB_ICONEXCLAMATION);
        exit(1);
    }

    DWORD windowframe = NULL;
    if( fullscreen ) {
        DEVMODE screenSettings;
        ZeroMemory( &screenSettings, sizeof( screenSettings ) );
        screenSettings.dmSize       = sizeof( screenSettings );
        screenSettings.dmPelsWidth  = width;
        screenSettings.dmPelsHeight = height;
        screenSettings.dmBitsPerPel = bpp;
        screenSettings.dmFields     = DM_BITSPERPEL | DM_PELSWIDTH | DM_PELSHEIGHT;

        long reso = ChangeDisplaySettings( &screenSettings, CDS_FULLSCREEN );
        if( reso != DISP_CHANGE_SUCCESSFUL ) {
            MessageBox( 0, "Could not initialize fullscreen window.", "Fatal error", MB_OK );
            exit(1); // elvileg jónak kell elennie mindig.
        }
        windowframe = NULL;
        ShowCursor( false );
    } else {
        windowframe = WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU ;
    }
    hWnd = CreateWindowEx( NULL, "WINCLASS", MAIN_WINDOW_TITLE,
        WS_POPUP | WS_VISIBLE | WS_CLIPSIBLINGS | WS_CLIPCHILDREN | windowframe,
        0, 0, width, height, NULL, NULL, GetModuleHandle( 0 ), NULL );

    if( hWnd == NULL ){
        MessageBox (HWND_DESKTOP, "cannot create window", "Error", MB_OK | MB_ICONEXCLAMATION);
        exit(1);
    }

    hDc = GetDC(hWnd);

    ShowWindow( hWnd, SW_SHOWDEFAULT );
    UpdateWindow( hWnd );
}