Messages

1

Graphics / Re: sf::Texture::~Texture() Crashes App On Exit

« on: November 15, 2016, 04:30:48 pm »

Even if this isn't the cause of the error, your use of threads is rather dangerous.

Thanks for the quick reply. I've felt it was error prone, but now you confirmed it, haha. Thanks for the explanation.

I managed to apply a quick-fix by eliminating the callback and querying the state every frame, like this:

Code: [Select]

if (download.isComplete()) {
    std::string data = download.getData();
    texture.loadFromMemory(data.c_str(), data.length());
    sprite.setTexture(texture);
}

But it's not what I wanted originally. So I guess my question changes to: How do I achieve this using a callback function? Do you have any suggestions on how to improve the code?

2

Graphics / sf::Texture::~Texture() Crashes App On Exit

« on: November 15, 2016, 02:05:49 pm »

Hello peeps,

I've been using SFML for quite some time now, and I have to say that I absolutely love it.

Currently I'm building a game engine + all sorts of tools for my future games, and I just threw together this little file downloader that can be used in combination with SFML resources' loadFromMemory() function.

It all works fine, the image is displayed correctly, but when I close the application, it crashes with an EXC_BAD_ACCESS error and shows me the assemly code for the destructor of the Texture and for some releasePool() method. I cannot seem to figure out why this is happening. It works without any problems with sf::Font and sf::SoundBuffer. Please help.

Download.cpp

(click to show/hide)

Download::Download(const URL& url) :
m_data(),
m_url(url),
m_size(0),
m_state(Stopped),
m_function([](bool, const std::string&) {}){
    fetchMetadata();
}

Download::~Download() {
    m_thread.join();
}

void Download::onComplete(std::function<void (bool success, const std::string&)> function) {
    m_function = function;
}

void Download::start() {
    m_state = Downloading;
   
    m_thread = std::thread(&Download::run, this);
}

int Download::getSize() const {
    return m_size;
}

Download::State Download::getState() const {
    return m_state;
}

bool Download::isComplete() const {
    return m_state == Complete;
}

void Download::fetchMetadata() {
    sf::Http http(m_url.getProtocol() + "://" + m_url.getHost());
    sf::Http::Request request(m_url.getPath(), sf::Http::Request::Head);
    sf::Http::Response response = http.sendRequest(request);

    if (response.getStatus() == sf::Http::Response::Ok) {
        m_size = std::stoi(response.getField("Content-Length"));
    }
}

void Download::run() {
    sf::Http http(m_url.getProtocol() + "://" + m_url.getHost());
    sf::Http::Request request(m_url.getPath(), sf::Http::Request::Get);
    sf::Http::Response response = http.sendRequest(request);
   
    bool success;
   
    if (response.getStatus() == sf::Http::Response::Ok) {
        m_state = Complete;
        m_data = response.getBody();
        success = true;
    } else {
        m_state = Error;
        success = false;
    }
   
    if (m_function) {
        m_function(success, m_data);
    }
}
 

main.cpp

(click to show/hide)

int main(int argc, const char * argv[]) {
    sf::Texture texture;
    sf::Sprite sprite;
   
    URL url("http://r.ddmcdn.com/s_f/o_1/cx_633/cy_0/cw_1725/ch_1725/w_720/APL/uploads/2014/11/too-cute-doggone-it-video-playlist.jpg");
    Download download(url);
   
    download.onComplete([&](bool success, const std::string& data) {
        texture.loadFromMemory(data.c_str(), data.length());
        sprite.setTexture(texture);
    });
   
    download.start();

    sf::RenderWindow window(sf::VideoMode::getDesktopMode(), "Downloading...");

    while (window.isOpen()) {
        sf::Event event;

        while (window.pollEvent(event)) {
            if (event.type == sf::Event::Closed) {
                window.close();
            }
        }

        window.clear(sf::Color(60, 60, 60));

        window.draw(sprite);

        window.display();
    }

    return 0;
}
 

If I replace sf::Texture and sf::Sprite with sf::Font and sf::Text respectively (and change the URL obviously), there is no problem at all.