c++ - SFML sf::Mouse::getPosition 方法无法写入正确的参数

Question

我的问题是，我已经在 Game::HandleInput() 方法中编写了这段代码，但我无法使 sf::Mouse::getPosition() 方法获取鼠标相对于窗口的坐标。没有争论，我不会得到错误。但是，船不能正常旋转。我试过 getPosition(m_window) 和 getPosition(&m_window)。我收到此错误:

no instance of overloaded function "sf::Mouse::getPosition" matches the argument list

编辑:更新了 WINDOW.H

Window.h:

class Window{
    //Constructers
public:
    Window();
    Window(const std::string& l_title, const sf::Vector2u& l_size);

    ...
private:
    sf::RenderWindow m_window;
    ...
}

编辑:添加了 WINDOW.CPP 的完整代码:

Window.cpp:

#include "Window.h"

Window::Window() {
    Setup("Window", sf::Vector2u(640, 480));
}
Window::Window(const std::string& l_title, const sf::Vector2u& l_size) {
    Setup(l_title, l_size);
}
Window::~Window() {
    Destroy();
}

void Window::Setup(const std::string& l_title,
    const sf::Vector2u& l_size)
{
    m_windowTitle = l_title;
    m_windowSize = l_size;
    m_isFullscreen = false;
    m_isDone = false;
    Create();
}
void Window::Create() {
    auto style = (m_isFullscreen ? sf::Style::Fullscreen
        : sf::Style::Default);
    m_window.create({ m_windowSize.x, m_windowSize.y, 32 },
        m_windowTitle, style);
}
void Window::Destroy() {
    m_window.close();
}
void Window::Update() {
    sf::Event event;
    while (m_window.pollEvent(event)) {
        if (event.type == sf::Event::Closed) {
            m_isDone = true;
        }
        else if (event.type == sf::Event::KeyPressed &&
            event.key.code == sf::Keyboard::F5)
        {
            ToggleFullscreen();
        }
    }
}
void Window::ToggleFullscreen() {
    m_isFullscreen = !m_isFullscreen;
    Destroy();
    Create();
}
void Window::BeginDraw() { m_window.clear(sf::Color::Black); }
void Window::EndDraw() { m_window.display(); }

bool Window::IsDone() { return m_isDone; }
bool Window::IsFullscreen() { return m_isFullscreen; }
sf::Vector2u Window::GetWindowSize() { return m_windowSize; }

void Window::Draw(sf::Drawable& l_drawable){
    m_window.draw(l_drawable);
}

编辑:更新了游戏。H

游戏.h:

class Game{
public:
    Game();
    ~Game();
    void HandleInput();
    void Update();
    void Render();
    Window* GetWindow();
private:
    ...
    Window m_window;
    ...
}

编辑:更新游戏.CPP

游戏.cpp:

Game::Game() : m_window("Multiplayer Space Shooter Game", sf::Vector2u(800, 600)) {
    // Setting up class members.
    m_shipText.loadFromFile("C:\\Users\\AliTeo\\Desktop\\Piksel çalışmaları\\ship_pixel2.png");
    m_ship.setTexture(m_shipText);
    m_ship.setOrigin(m_shipText.getSize().x / 2, m_shipText.getSize().y / 2);
    m_ship.setPosition(320, 240);
}
void Game::HandleInput() {
    ...
    //Get the angle between ship and mouse.
    //Error if there is an argument in getPosition()
    m_angle = atan2(sf::Mouse::getPosition().y - m_ship.getPosition().y, sf::Mouse::getPosition().x - m_ship.getPosition().x); //TO DO: getPosition(&Relative To)
    m_angle *= 180 / m_PI;
    ...
}
Window* Game::GetWindow() { return &m_window; }

编辑:添加了 MAIN.CPP

Main.cpp

int main() {
    Game game;
    while (!game.GetWindow()->IsDone()) {
        game.HandleInput();
        game.Update();
        game.Render();
    }
}

Answer 1

首先让我给你一个我认为是重现你的问题的最小例子:

#include <SFML/Graphics.hpp>

class MyWindow {
public:
    MyWindow()
    : m_window({800, 600, 32}, "my window title") {}

private:
    sf::RenderWindow m_window;
};

int main() {
    MyWindow window;
    sf::Mouse::getPosition(window);
}

这段代码无法编译(诚然，编译后不会做任何有趣的事情，但这不是重点)。我怀疑如果您尝试编译它，它会给您带来与您当前遇到的错误相同的错误。

请注意，这是我们在谈论 MCVE 时所期望的: 这段代码简短、简单，显示了错误，如果不是因为错误，也可以编译。

此外，它使错误变得非常清楚，如果您尝试自己想出一个 MCVE，您可能已经解决了您的问题而无需在此处发布问题，这肯定会节省您的时间。

---

对比你的代码:

m_angle = atan2(sf::Mouse::getPosition().y - m_ship.getPosition().y
               ,sf::Mouse::getPosition().x - m_ship.getPosition().x
               );
//TO DO: getPosition(Relative To)

这段代码是合法的，但你解释说它不正确，你想把它变成类似这样的东西:

m_angle = atan2(sf::Mouse::getPosition(m_window).y - m_ship.getPosition().y
               ,sf::Mouse::getPosition(m_window).x - m_ship.getPosition().x
               );
//TO DO: getPosition(Relative To)

...无法编译。

但是，在此范围内 m_window 是一个 Window 而不是 sf::RenderWindow!

问题是您正在传递对封装 sf::RenderWindow，但不能转换为 sf::Window& 本身。因此，您不能将其传递给 sf::Mouse::getPosition它不需要任何东西或 sf::Window&，但肯定不是 Window& 或 MyWindow&。

---

有很多方法可以解决这个问题。下面介绍了其中两个:

#include <SFML/Graphics.hpp>

class MyWindow {
public:
    MyWindow()
    : m_window({800, 600, 32}, "my window title") {}

    // you could add an accessor
    const sf::Window& getSfmlWindow() const { return m_window; }

    // you may also expose a method to get the mouse position
    // relatively to this window
    const sf::Vector2i getMousePosition() const {
        return sf::Mouse::getPosition(m_window);
    }

private:
    sf::RenderWindow m_window;
};

int main() {
    MyWindow window;
    sf::Vector2i mouse_position;
    // this won't work! window isn't convertible to sf::Window&
    // mouse_position = sf::Mouse::getPosition(window);

    // using the accessor
    mouse_position = sf::Mouse::getPosition(window.getSfmlWindow());

    // or the exposed method
    mouse_position = window.getMousePosition();
}