Messages

1

System / Problem with threads on Linux

« on: July 15, 2017, 03:46:05 pm »

I am trying to separate the event thread and the rendering thread in my game.

To try it out, I ran the following code from the SFML tutorials :

void renderingThread(sf::RenderWindow* window)
{
    // the rendering loop
    while (window->isOpen())
    {
        // draw...

        // end the current frame
        window->display();
    }
}

int main()
{
    // create the window (remember: it's safer to create it in the main thread due to OS limitations)
    sf::RenderWindow window(sf::VideoMode(800, 600), "OpenGL");

    // deactivate its OpenGL context
    window.setActive(false);

    // launch the rendering thread
    sf::Thread thread(&renderingThread, &window);
    thread.launch();

    // the event/logic/whatever loop
    while (window.isOpen())
    {
        sf::Event event;
        while (window.pollEvent(event)) {
            if (event.type == sf::Event::Closed) window.close();
        }
    }

    return 0;
}
 

However, after compiling and running this program, I get this error :

Code: [Select]

[xcb] Unknown request in queue while dequeuing
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
test: xcb_io.c:165: dequeue_pending_request: Assertion `!xcb_xlib_unknown_req_in_deq' failed.
Aborted (core dumped)

I read in this topic that this problem can be solved by calling XInitThreads(), but that it is a bad solution, because not only is it not cross-platform, but it adds overhead and might slow down everything.

It is explicitly stated in the tutorials to manage events in the main thread, which is the case here, so I think it is a bit misleading to promote a solution that is not cross platform in the tutorials.

I also tested it with std::thread and i get the same results.
I sometimes get this error message repeated multiple times : `Error while creating udev enumerator`, so I believe the problem comes from SFML.

For information, my OS is manjaro Linux, and I use SFML 2.4.2.

2

Graphics / Re: Is it worth it to create as few sprites as possible

« on: July 05, 2016, 02:31:22 pm »

thank you very much for your help

3

Graphics / Is it worth it to create as few sprites as possible

« on: July 05, 2016, 01:25:17 pm »

I am currently making a game with SFML and I wonder if I should reuse the same sf::Sprite to draw all of the entities that are on screen.
For example, if I wanted to draw 20 entities with the same texture, should I make them share the same sprite and move it to the position of the entity before drawing it or is it ok to use 20 sprites sharing the same sf::Texture ?

Same question for the terrain because there are much more sprites involved.

I am worried about slowing the game a lot, but I read that the important thing was to reuse the same texture instance so I am not sure that it is necessary to reuse the same sprite for every entity.