在 SFML 中将生命周期 function 添加到 object

Question

I am currently trying to create an object which after a certain period of time appears on screen. The object appears but it does so immediately and is visible. How would I change this so the object starts off screen and then moves onscreen after a certain interval of time? In my header file I have the function:

void time(sf::Time 15, int x_pos, int y_pos){
// spawn = true;
body-> setPosition(x_pos,y_pos);
}

and in the cpp file I have:

Game(int size,std::string title){
    win = new sf::RenderWindow(sf::VideoMode(size,size),title);
    powerup = new Powerup(-1,-1);
int x_pos = rand() % 100 + 1;
int y_pos = rand() % 100 + 1;
}
void run(){
    while (win->isOpen()){
        Event e;
        while (win->pollEvent(e)){
            if(e.type == Event::Closed){
                win->close();
            }

I have gotten thus far but don't know how to ensure that it is right.

Answer 1

I decided to make the object handle itself via update function, you can always change it and manage it from while window.isOpen() or wherever else you would like to.

Object

Object{
public:
    Object(sf::Vector2f position) : object(sf::Vector2f(20.f,20.f)){//object size = {20, 20}
        is_visible = false;
        object.setPosition(position);
    }
    void update(float deltaTime){
        if(!is_visible){//hidden        
            spawnTimer += deltaTime;
            if(spawnTimer>=10.f)//10 seconds
                setVisible(true);
        }
    }
    void setVisible(bool& is_visible){
        this->is_visible = is_visible;
    }
    const bool& isVisible() const {
        return is_visible;
    }
private:
    float spawnTimer;
    bool is_visible;
    sf::RectangleShape object;
};

Main

main(){
    sf::RenderWindow window(sf::VideoMode(size, size), title);
    sf::Clock clock;
    float deltaTime = 0.f;
    Object myObject(sf::Vector2f(100.f,100.f);
    while(window.isOpen()){
        deltaTime = clock.restart().asSeconds();
        //skipped events handling since it is irrelevant    
        myObject.update(deltaTime);
        
        //rendering
        window.clear();
        if(myObject.isVisible)//if is visible draw it
            //draw myObject
        //...
        window.display();
    }
}