GameBoy\Keyboard::matchKey PHP Method

    public function matchKey($key)
    {
        //Maps a keyboard key to a gameboy key.
        //Order: Right, Left, Up, Down, A, B, Select, Start
        $keyIndex = array_search($key, Settings::$keyboardButtonMap);
        if ($keyIndex === false) {
            return -1;
        }
        return $keyIndex;
    }