使用矢量 push_back 代码创建对象副本时遇到问题

Question

每次我按下 space 按钮时，我都在尝试复制 RectangleShape rect1，但我并没有这样做，它似乎只是在我释放 space键。我不明白为什么，有人帮我吗？

这是我的代码：

int main() {

class shape {
public:
    RectangleShape rect1;
};

shape getShape;
getShape.rect1.setSize(Vector2f(100, 100));
getShape.rect1.setFillColor(Color(0, 255, 50, 30));

RenderWindow window(sf::VideoMode(800, 600), "SFML Game"); 
window.setFramerateLimit(60);          

window.setKeyRepeatEnabled(false);

bool play = true;
Event event;    
while (play == true) {

    while (window.pollEvent(event)) {
        if (event.type == Event::Closed) {
            play = false;
        }
    }

    window.clear();

    vector <shape> Vec;

    if (Keyboard::isKeyPressed(Keyboard::Space)) {
        Vec.push_back(getShape);
    }

    for (int i = 0; i < Vec.size(); ++i) {
        window.draw(Vec[i].rect1);
    }

    window.display();
}

window.close();
return 0;
}

Answer 1

你需要把vector放在循环外面，否则你每次都会创建一个新的空的：

int main() {
    // If you need to use this class in something other than main,
    // you will need to move it outside of main.
    class shape {
    public:
        RectangleShape rect1;
    };

    // But in this particular case you don't even need a class,
    // why not just use RectangleShape?
    shape getShape;
    getShape.rect1.setSize(Vector2f(100, 100));
    getShape.rect1.setFillColor(Color(0, 255, 50, 30));

    RenderWindow window(sf::VideoMode(800, 600), "SFML Game"); 
    window.setFramerateLimit(60);          

    window.setKeyRepeatEnabled(false);

    bool play = true;
    Event event;
    std::vector<shape> Vec; // Put your vector here!

    // play is already a bool, so you don't need == true
    while (play) {
        while (window.pollEvent(event)) {
            if (event.type == Event::Closed) {
                play = false;
            }
        }

        window.clear();

        if (Keyboard::isKeyPressed(Keyboard::Space)) {
            Vec.push_back(getShape);
        }

        for (int i = 0; i < Vec.size(); ++i) {
            window.draw(Vec[i].rect1);
        }

        window.display();
    }

    window.close();
    return 0;
}

使用矢量 push_back 代码创建对象副本时遇到问题

having trouble creating copies of objects using vector push_back code

c++

sfml