Flickering image using sfml 2.0

[dignus93]

Hi there,
I'm using CodeBlocks, sfml 2.0, Windows 10.
I'm having some flickering image troubles. If I set the background the image doesn't even appear, if i remove the background the image appears but it flickers.
I show my main and my Graphic class.

  #include <iostream>
    #include "Card.h"
    #include "Special_Card.h"
    #include "Deck.h"
    #include "time.h"
    #include "Graphic.h"
    #include <SFML/Window.hpp>
    #include <SFML/Graphics.hpp>
    #include <string>
    #include <vector>
    #include <memory>
    #include <string>
    #include <sstream>
    using namespace std;

    int main()
    {
        Graphic * graphic = new Graphic(0);
        sf::RenderWindow window;
        Deck deck0;
        deck0.buildDeck();
        graphic->CreateWindow(window, deck0);
    }
 

And this my graphic class definition

    #include "Graphic.h"
    #include "SFML/Graphics.hpp"
    #include <iostream>
    #include <string>
    #include "Card.h"
    #include <string>
    #include <sstream>

    Graphic::Graphic(int offset)
    {
        this->offset = offset;
    }

    int Graphic::CreateWindow(sf::RenderWindow& window, Deck &deck0)
    {
        sf::Vector2i screenDimensions(800, 600);
       
        //Dimension of Window
        window.create(sf::VideoMode(screenDimensions.x, screenDimensions.y), "BlackJack", sf::Style::Titlebar | sf::Style::Close);

        int index = 0;
        window.setKeyRepeatEnabled(false);

        //set the background
        sf::Texture bTexture;
        sf::Sprite bImage;
        if(!bTexture.loadFromFile("Background.png"))
            std::cout<< "Error" <<std::endl;

        bImage.setTexture(bTexture);
        bImage.setScale(1.0, (float)screenDimensions.y / bTexture.getSize().y);

        //MAIN LOOP----------------------
        while(window.isOpen())
        {
            sf::Event Event;
            while(window.pollEvent(Event))
            {
                switch(Event.type)
                {
                //chiude la finestra quando premi il tasto chiudi
                case sf::Event::Closed:
                    window.close();
                    break;

                //fa qualcosa quando premi il tasto h sulla tastiera
                case sf::Event::KeyPressed:
                    if(Event.key.code == sf::Keyboard::H)
                    {

                            Card * y = deck0.dealFirst();
                            drawCard(window,y->graphNumber,y->getSeed(),offset);   //THIS IS THE FUNCTION WHICH DRAW THE IMAGE
                            offset = offset + 100;
                            window.display();

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

                    break;
                }
            }
            window.draw(bImage);   //if I comment this the images appears but they flickers
            window.display();
        }
    }
 

[Hapax]

Don't forget to clear the window.

Remember:

window.clear();
window.draw();
window.display();

[dignus93]

I solved a part of the problem. You have illuminate me with this window.clear() function (it is really important). Now I want to ask: if i set a background and an image on it, i will call window.clear() at the beginning of the main while then I will call the draw function for the background and after the draw function for the image. Finally i will call the window.display() function? Is this the right order?

[G.]

Yes.

[dignus93]

ok I have solved the problem of flickering. Now the problem is that the function don't do what I want.
This "CreateWindow" function has the main loop. In the main loop I want a fixed background and, every time I press the H button, I want to draw a Card on the background. What's the problem here? My function draw the cards but when I press H the previous card is deleted and the next card is drawn.
This is something about the event I think, because every time an event happens (I move the mouse, I press an other key etc) the previous card is deleted...   

[Hapax]

I suppose it would depend on what your drawCard function does...

Remember that you need to draw everything visible every single frame. If there are multiple cards, you need to draw multiple cards between clear and display.

Also, only clear and display the window once per frame.