C++ 和 SFML，没有重载函数“sf::RenderWindow.draw()”的实例与参数列表匹配

Question

I am currently trying to make a simple pong game with SFML in C++. I consistently get the error in the main file.

#include <iostream>
#include "Ball.h"

Ball b;

int main()
{
    // create the window
    sf::RenderWindow window(sf::VideoMode(1200, 600), "My window");

    // run the program as long as the window is open
    while (window.isOpen())
    {
        // check all the window's events that were triggered since the last iteration of the loop
        sf::Event event;
        while (window.pollEvent(event))
        {
            // "close requested" event: we close the window
            if (event.type == sf::Event::Closed)
            window.close();
        }

        // clear the window with black color
        window.clear(sf::Color::Black);

        // draw everything here...
        window.draw(b);

        // end the current frame
        window.display();
    }

    return 0;
}

This is the ball.h file:

#pragma once
#include <iostream>
#include <SFML/Window.hpp>
#include <SFML/Graphics.hpp>
class Ball
{
public:
    double x, y;
    int Radius;

    void Render(int Rad, sf::Color BallColour) {
        sf::CircleShape shape(Rad);
        // set the shape color to green
        shape.setFillColor(BallColour);
    }
};

I am unsure as to why the error occurs. Any help would be appreciated.

Answer 1

sf::RenderWindow::draw requires an implementation of sf::Drawable . You can either pass sf::CircleShape (it's a sf::Drawable ) directly or implement sf::Drawable and delegate the call.

class Ball : public sf::Drawable {
public:
    double x, y;
    int Radius;

    void draw(sf::RenderTarget& target, sf::RenderStates states) const override {
      sf::CircleShape shape(Radius);
      shape.setFillColor(BallColour);
      shape.draw(target, states);
    }
};

Answer 2

You had not call function of render, you just wrote window.draw(b) , and programm dont know what do you mean. In Ball.h you should write:

 #pragma once
    #include <iostream>
    #include <SFML/Window.hpp>
    #include <SFML/Graphics.hpp>
    class Ball
    {
    public:
        double x, y;
        int Radius;
    
        void Render(int Rad, RenderWindow& window) {
            sf::CircleShape shape(Rad);
            // set the shape color to green
            shape.setFillColor(sf::Color::Green);
            shape.setPosition(600, 300);//SETTING POSITION OF THE BALL
            window.draw(shape);//if you know what is reference on variable, you will understand what is it
        }
    };

And in your main.cpp you shhould call your function Render:

#include <iostream>
#include "Ball.h"

int main()
{
    // create the window
    sf::RenderWindow window(sf::VideoMode(1200, 600), "My window");

    Ball b; //I advice you to create object of class in main function

    // run the program as long as the window is open
    while (window.isOpen())
    {
        // check all the window's events that were triggered since the last iteration of the loop
        sf::Event event;
        while (window.pollEvent(event))
        {
            // "close requested" event: we close the window
            if (event.type == sf::Event::Closed)
            window.close();
        }

        // clear the window with black color
        window.clear(sf::Color::Black);

        b.Render(10, window);// give the function reference on window

        // end the current frame
        window.display();
    }

    return 0;
}