Messages

1

General / Re: Hashing sf::Event

« on: August 02, 2018, 03:04:07 pm »

I actually read about that on Google before trying it myself, but since sf::Event seems to use union for its members I don't know how to hash all the members like you say. Good point about the modifiers!

2

General / Hashing sf::Event

« on: August 02, 2018, 01:54:37 pm »

I wish to be able to hash sf::Event in a reliable manner, because I want to use events as keys in std::unordered_map. This is the best I've come up with so far:

int sfhash(const sf::Event & e) {
    int seed = 1000000 * e.type;
    int mod = 1;
    switch (e.type) {
        case sf::Event::KeyPressed:
            seed = seed + e.key.code;
            break;

        case sf::Event::KeyReleased:
            seed = -seed - e.key.code;
            mod = -1;
            break;

        case sf::Event::MouseButtonPressed:
            seed = seed + e.mouseButton.button;
            break;

        case sf::Event::MouseButtonReleased:
            seed = -seed - e.mouseButton.button;
            mod = -1;
            break;

        default:
            break;
    }
    if (sf::Keyboard::isKeyPressed(sf::Keyboard::LControl)
        || sf::Keyboard::isKeyPressed(sf::Keyboard::RControl))
    {
        seed += mod * 1000;
    }
    if (sf::Keyboard::isKeyPressed(sf::Keyboard::LShift)
        || sf::Keyboard::isKeyPressed(sf::Keyboard::RShift))
    {
        seed += mod * 2000;
    }
    if (sf::Keyboard::isKeyPressed(sf::Keyboard::LAlt)) {
        seed += mod * 3000;
    }
    return seed;
}

Can you tell me a reason why this will fail, or if there is a much simpler way to do it that I didn't think of?