我在 SFML sf::RenderWindow 中只看到黑屏

Question

我尝试在一个 c++ windows 窗体项目（这里也是新的 :D）中使用 SFML 的优点（我还是新手）。我的想法是当事件发生时，此 SFML 窗口会弹出显示图像。我已经设法让 SFML 窗口在事件发生时弹出，但它只出现在空白屏幕上，但没有显示我想要的纹理......这是涉及 SFML 的代码摘录，带有 "// 。 ." 我会删掉不必要的代码：

BatteryAlarmDlg.h

class CBatteryAlarmDlg : public CDialog
{
    // ... 
    protected:
    // ...

    // timers
    Timer m_tPowerCheck; // the struct Timer has just two members - int id and int duration
    Timer m_tWindowRefresh;

    // sounds
    sf::SoundBuffer m_sfsbWarningMessageBuffer;
    sf::Sound m_sfsWarningMessageSound;
    std::string m_sPathToWarningMessageSoundFile;

    // sfml window management support
    sf::RenderWindow m_sfwChangePowerMessage;
    sf::Texture m_sftChangePowerMessage;
    sf::RectangleShape m_sfrChangePowerMessage;
    bool m_bIsWindowAlive;
    sf::Event m_sfeEvent;

    // ...
};

在上面的代码中，我只是声明了成员。

BatteryAlarmDlg.cpp

// ...
BOOL CBatteryAlarmDlg::OnInitDialog()
{
    // ...
    /// init timers ///
    m_tPowerCheck = Timer(42, 1000); // a timer with id == 42 and with a duration == 1,000 ms
    SetTimer(m_tPowerCheck.id, m_tPowerCheck.duration, nullptr);
    m_tWindowRefresh = Timer(1, 15);
    SetTimer(m_tWindowRefresh.id, m_tWindowRefresh.duration, nullptr);

    /// init sounds ///
    m_sPathToWarningMessageSoundFile = "warning-message-2.wav";
    if (!m_sfsbWarningMessageBuffer.loadFromFile(m_sPathToWarningMessageSoundFile))
    {
        MessageBox("Error loading of warning message sound file!");
    }
    m_sfsWarningMessageSound.setBuffer(m_sfsbWarningMessageBuffer);

    /// init messages windows ///
    m_sfwChangePowerMessage.setFramerateLimit(60);
    if (!m_sftChangePowerMessage.loadFromFile("ChagePowerMessage.png"))
    {
        MessageBox("Error loading of warning message image file!");
    }
    m_sfrChangePowerMessage.setSize
        (
            sf::Vector2f(m_sfwChangePowerMessage.getSize().x, m_sfwChangePowerMessage.getSize().y)
        );

    m_sfrChangePowerMessage.setPosition(0, 0);
    m_sfrChangePowerMessage.setTexture(&m_sftChangePowerMessage);
    m_bIsWindowAlive = false;

    return TRUE;  // return TRUE  unless you set the focus to a control
}
    // ...
void CBatteryAlarmDlg::OnTimer(UINT_PTR nIDEvent)
{
    if (nIDEvent == m_tPowerCheck.id)
    {

        if (GetSystemPowerStatus(&m_spsPower) == 0)
        {
            // message = "Error: Could not get the system power status!";
            MessageBox("Error: Could not get the system power status!");
        }       
        if (m_spsPower.ACLineStatus == 0 & m_iPowerChange == 1)
        {
            if (!m_sfwChangePowerMessage.isOpen())
            {
                m_sfwChangePowerMessage.create(sf::VideoMode(800, 600), "Battery allarm : System Power Changed!");
            }
            m_sfwChangePowerMessage.clear();
            m_sfwChangePowerMessage.draw(m_sfrChangePowerMessage);
            m_sfwChangePowerMessage.display();
            m_iPowerChange = 0;
            m_sfsWarningMessageSound.play();
            m_bIsWindowAlive = true;
        }

        if (m_spsPower.ACLineStatus == 1 & m_iPowerChange == 0)
        {
            m_iPowerChange = 1;
        }

    }


    if (nIDEvent = m_tWindowRefresh.id)
    {
        if (m_bIsWindowAlive)
        {
            while (m_sfwChangePowerMessage.pollEvent(m_sfeEvent))
            {
                if
                    (
                        m_sfeEvent.type == sf::Event::Closed ||
                        (m_sfeEvent.type == sf::Event::KeyPressed && m_sfeEvent.key.code == sf::Keyboard::Escape)
                    )
                {
                    m_bIsWindowAlive = false;
                }
            }

            m_sfwChangePowerMessage.clear();
            m_sfwChangePowerMessage.draw(m_sfrChangePowerMessage);

            m_sfwChangePowerMessage.display();
        }

        if(!m_bIsWindowAlive && m_sfwChangePowerMessage.isOpen())
        {
            m_sfwChangePowerMessage.close();
        }
    }
    CDialog::OnTimer(nIDEvent);
}

背后的基本思想是如果有一个事件并且第一个计时器（m_tPowerCheck 每 1 秒）用完，然后显示绘制图像的 SFML 窗口，然后播放声音。 每 15 毫秒 (m_tWindowRefresh) 检查 sfml 窗口是否打开并重绘图片 - 在这里我不确定是否有必要，因为这是一张静止图像，但最初我认为黑屏是因为我不刷新它不断地。但仍然 - 只有黑屏...：\

编辑：SFML 的声音效果很好。

Answer 1

您似乎将sf::RectangleShape m_sfrChangePowerMessage 的大小设置为sf::Vector2f(0,0)。 发生这种情况是因为您调用：

m_sfrChangePowerMessage.setSize
        (
            sf::Vector2f(m_sfwChangePowerMessage.getSize().x, m_sfwChangePowerMessage.getSize().y)
        );

在创建窗口之前：

m_sfwChangePowerMessage.create(sf::VideoMode(800, 600), "Battery allarm : System Power Changed!");

我的示例解决方案是替换

m_sfrChangePowerMessage.setSize
        (
            sf::Vector2f(m_sfwChangePowerMessage.getSize().x, m_sfwChangePowerMessage.getSize().y)
        );

致m_sfrChangePowerMessage.setSize(sf::Vector2f(800,600));

您也可能对Observer Pattern 感兴趣，它可能对您的申请有所帮助。