How do I duplicate a sprite on screen multiple times with each sprite having the same code?

Question

I'm trying to duplicate sprites on the screen, but I can't do that without making multiple sprites.

I found somebody else ask the same question but what I am trying to do is, for example, click somewhere in the window and make the sprite appear there. I tried to draw that sprite in two places on the screen (which worked) but I had also added collision for the sprite and the player sprite, which for some reason, did not stop the player from moving into the sprite.

 #include <SFML/Graphics.hpp>
 #include <SFML/Window/Keyboard.hpp>

bool collision(sf::FloatRect r1, sf::FloatRect r2)
{
    sf::FloatRect intersection;
    return r1.intersects(r2, intersection);
}

bool collision(sf::Shape const & r1, sf::Shape const & r2)
{
    return collision(r1.getGlobalBounds(), r2.getGlobalBounds());
}
int main(){
sf::RenderWindow window(sf::VideoMode(800,600),"INSERT_WINDOW_TITLE", 
sf::Style::Titlebar | sf::Style::Close);
sf::RectangleShape player(sf::Vector2f(20.f,20.f));
player.setFillColor(sf::Color::Blue);
sf::RectangleShape rect(sf::Vector2f(20.f,20.f));
rect.setFillColor(sf::Color::Red);
int mousex = 400;
int mousey = 240;
rect.setPosition(400,240);
while(window.isOpen()){
    sf::Event event;
    if(collision(player,rect) == false){
        if(sf::Keyboard::isKeyPressed(sf::Keyboard::W)) 
player.move(0.f,-1.f);
        if(sf::Keyboard::isKeyPressed(sf::Keyboard::S)) 
player.move(0.f,1.f);
        if(sf::Keyboard::isKeyPressed(sf::Keyboard::A)) 
player.move(-1.f,0.f);
        if(sf::Keyboard::isKeyPressed(sf::Keyboard::D)) 
player.move(1.f,0.f);
    }
    if(sf::Mouse::isButtonPressed(sf::Mouse::Left)){
        mousex = sf::Mouse::getPosition().x;
        mousey = sf::Mouse::getPosition().y;
    }
    while(window.pollEvent(event)){
         if (event.type == sf::Event::Closed)
            window.close();
    }
    window.clear(sf::Color::Black);
    window.draw(player);
rect.setPosition(400,240); // did not have any collision with this rect
    window.draw(rect);
rect.setPosition(mousex,mousey); // I set this position after the 
previous one, which is why it HAD collision
    window.draw(rect);
    window.display();
}
}

As you can see, I added comments to where the "error" occurred. The problem is that only the second sf::RectangleShape had collision and the sprite was being drawn too fast for any real collision (or at least that is what I am guessing). (I'm thinking about duplicating sprites without duplicating code 1000 times) How would I go about fixing this problem?

score 3 · Accepted Answer · answered Dec 27 '18 at 03:46

The problem is that you're only checking for collision once per loop. So, if you draw the rectangle twice, only one of them will collide. To resolve the problem, you should check

if(collision(player,rect) == false)

which, by the way, can be abbreviated to

if(!collision(player,rect))

again after you change the position of the rect on this line:

rect.setPosition(mousex,mousey); // I set this position after the previous one, which is why it HAD collision

How do I duplicate a sprite on screen multiple times with each sprite having the same code?

1 Answers1