No error, but cannot display sf::Text from class.

[Alg450]

Hi,

I'm sort of new to C++ and SFML, so if this is something obvious I apologize. I want to save myself some time by defining a button class, which will contain an instance of an sf::RectangleShape (for the background / body of the button) and an instance of sf::Text (for the tooltip / functional discription, etc). Right now I'm just trying to display both the text and the button, there is no logic for checking for clicks, or anything like that. When I compile and run the code shown below, I get no errors. I expect the code to draw a background (which it does) a small red square (defined within the class button, which it does) a line of text in blue (defined within the class button, which it doesn't draw). and a line of text in green (defined within main(), which it does, this was primarily to test if I was just using the sf::Font and sf::Text member functions incorrectly). I want to know why the text defined in the class isn't being drawn.

#include <SFML/Graphics.hpp>
sf::RenderWindow window(sf::VideoMode(800,600), "Class Test",sf::Style::Titlebar|sf::Style::Close);

class button
{
private:
    sf::RectangleShape rect;
    sf::Text text;
public:
    void setup(sf::Font font)
    {
        rect.setFillColor(sf::Color::Red);
        rect.setSize(sf::Vector2f(10,10));
        rect.setPosition(5,5);

        text.setColor(sf::Color::Blue);
        text.setString("Hello World");
        text.setPosition(30,30);

        text.setFont(font);
    }
    void drawit()
    {
        window.draw(rect);
        window.draw(text);
    }
};

int main()
{
    sf::Texture backgroundt;
    if (!backgroundt.loadFromFile("resources/background.png"))
    {
        return EXIT_FAILURE;
    }
    sf::Sprite backgrounds(backgroundt);
    sf::Event event;
    window.setFramerateLimit(60);
    window.setVerticalSyncEnabled(true);

    sf::Font fonty;
    if(!fonty.loadFromFile("resources/sansation.ttf"))
    {
        return EXIT_FAILURE;
    }

    sf::Text texty;

    texty.setColor(sf::Color::Green);
    texty.setString("Hello World");
    texty.setPosition(50,50);

    texty.setFont(fonty);

    button buddy;
    buddy.setup(fonty);

    while(window.isOpen())
    {
        while (window.pollEvent(event))
        {
            if ((event.type == sf::Event::Closed)||((event.type == sf::Event::KeyPressed)&&(event.key.code == sf::Keyboard::Escape)))
            {
                window.close();
            }
        }
        window.clear();
        window.draw(backgrounds);
        window.draw(texty);
        buddy.drawit();
        window.display();
    }
    return EXIT_SUCCESS;
}
 

[Laurent]

I want to know why the text defined in the class isn't being drawn.

Bevcause it uses a local copy of the font, which is destroyed at the end of the setup function. You should rather pass the font by reference.

[Alg450]

Thanks, I modified my code thusly and it worked:

    void setup(sf::Font* font)
    {
        rect.setFillColor(sf::Color::Red);
        rect.setSize(sf::Vector2f(10,10));
        rect.setPosition(5,5);

        text.setColor(sf::Color::Blue);
        text.setString("Hello World");
        text.setPosition(30,30);

        text.setFont(*font);
    }

...

buddy.setup(&fonty);

[Hiura]

Quick tip: use a reference instead of a pointer.

Why? Because with a pointer you can get nullptr (or 0, or NULL). With a reference you know the variable is bound to an actual sf::Font object. Hence, less bugs.

Beside that, you don't need to use the dereference operator on your pointer.