Text is flickering

[Miraz]

Hello !

Im drawing player position on top of screen and it's flickering, why ?

void RenderingThread(sf::RenderWindow* window)
{
    // Rendering loop
    cout << "Starting rendering loop"<< endl;
    while(window->isOpen())
    {
        // Clear window
        window->clear(sf::Color::White);

        // draw...
        window->draw(pSprite);
        window->draw(StaticText);

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

void InitSettings()
{
    if(font.loadFromFile("Prototype.ttf")){
     StaticText.setFont(font);
     StaticText.setCharacterSize(20);
     StaticText.setColor(sf::Color::Red);
     StaticText.setPosition(0,0);
     }

}

 

This line is inside my main loop

StaticText.setString("pPositionX: " + ToString(pPositionX) + " pPositionY: " + ToString(pPositionY) );

[Jesper Juhl]

Try this http://www.sfml-dev.org/documentation/2.1/classsf_1_1Window.php#a59041c4556e0351048f8aff366034f61

[Miraz]

Hi Jesper Juhl, it's still flickering ! i also limited my fps to 60.

[Jesper Juhl]

Either use framerate limit or vertical sync. Never both at the same time - they interact badly (this is documented in the tutorials).

[AlexAUT]

I'm guessing you are using one thread for rendering and one thread for your "main" loop. And now both threads try to access the sf::Text instance at the same time = race condition = undefined behaviour = flickering.

If so, use a mutex to protect the variable or just don't use 2threads, because you won't gain any performance advantage out of it


AlexAUT

[StormWingDelta]

Multi-Threading will only be useful for larger projects to say the least so I wouldn't recommend using it either until you have to.  Could be the main cause of the issues you are having.  Now if you've completely split rendering and updating and have the two threads right you shouldn't be getting any flickering unless the update and rendering loops have too much time between them.

[Miraz]

Thank you for multiple responds, this forum is very helpfull when needed !

Indeed i use other thread to draw stuff on screen, i tought it is good to separate tasks on own threads. Im now clearing renderthread and implenting rendering in main loop. I also made decision to use VSYNC , not frame limiter.

I will update here if more problems occurs on text flickering!