If a window is open, only update joystick connections on WM_DEVICECHANGE message

src/SFML/Window/Win32/JoystickImpl.cpp

@@ -44,10 +44,13 @@ namespace
         bool connected;
         sf::Clock timer;
     };
-
     const sf::Time connectionRefreshDelay = sf::milliseconds(500);
+
     ConnectionCache connectionCache[sf::Joystick::Count];
 
+    // If true, will only update when WM_DEVICECHANGE message is received
+    bool lazyUpdates = false;
+
     // Get a system error string from an error code
     std::string getErrorString(DWORD error)
     {
@@ -150,19 +153,7 @@ namespace priv
 void JoystickImpl::initialize()
 {
     // Perform the initial scan and populate the connection cache
-    for (unsigned int i = 0; i < Joystick::Count; ++i)
+    updateConnections();
-    {
-        ConnectionCache& cache = connectionCache[i];
-
-        // Check if the joystick is connected
-        JOYINFOEX joyInfo;
-        joyInfo.dwSize = sizeof(joyInfo);
-        joyInfo.dwFlags = 0;
-        cache.connected = joyGetPosEx(JOYSTICKID1 + i, &joyInfo) == JOYERR_NOERROR;
-
-        // start the timeout
-        cache.timer.restart();
-    }
 }
 
 
@@ -176,27 +167,39 @@ void JoystickImpl::cleanup()
 ////////////////////////////////////////////////////////////
 bool JoystickImpl::isConnected(unsigned int index)
 {
-    // We check the connection state of joysticks only every N milliseconds,
-    // because of a strange (buggy?) behavior of joyGetPosEx when joysticks
-    // are just plugged/unplugged -- it takes really long and kills the app performances
     ConnectionCache& cache = connectionCache[index];
-    if (cache.timer.getElapsedTime() > connectionRefreshDelay)
+    if (!lazyUpdates && cache.timer.getElapsedTime() > connectionRefreshDelay)
     {
-        cache.timer.restart();
-
         JOYINFOEX joyInfo;
         joyInfo.dwSize = sizeof(joyInfo);
         joyInfo.dwFlags = 0;
-
         cache.connected = joyGetPosEx(JOYSTICKID1 + index, &joyInfo) == JOYERR_NOERROR;
-        return cache.connected;
+
-    }
+        cache.timer.restart();
-    else
-    {
-        return cache.connected;
     }
+    return cache.connected;
 }
 
+////////////////////////////////////////////////////////////
+void JoystickImpl::setLazyUpdates(bool status)
+{
+    lazyUpdates = status;
+}
+
+////////////////////////////////////////////////////////////
+void JoystickImpl::updateConnections()
+{
+    for (unsigned int i = 0; i < Joystick::Count; ++i)
+    {
+        JOYINFOEX joyInfo;
+        joyInfo.dwSize = sizeof(joyInfo);
+        joyInfo.dwFlags = 0;
+        ConnectionCache& cache = connectionCache[i];
+        cache.connected = joyGetPosEx(JOYSTICKID1 + i, &joyInfo) == JOYERR_NOERROR;
+
+        cache.timer.restart();
+    }
+}
 
 ////////////////////////////////////////////////////////////
 bool JoystickImpl::open(unsigned int index)

src/SFML/Window/Win32/JoystickImpl.hpp

@@ -77,6 +77,20 @@ public:
     ////////////////////////////////////////////////////////////
     static bool isConnected(unsigned int index);
 
+    ////////////////////////////////////////////////////////////
+    /// \brief Enable or disable lazy enumeration updates
+    ///
+    /// \param status Whether to rely on windows triggering enumeration updates
+    ///
+    ////////////////////////////////////////////////////////////
+    static void setLazyUpdates(bool status);
+
+    ////////////////////////////////////////////////////////////
+    /// \brief Update the connection status of all joysticks
+    ///
+    ////////////////////////////////////////////////////////////
+    static void updateConnections();
+
     ////////////////////////////////////////////////////////////
     /// \brief Open the joystick
     ///

src/SFML/Window/Win32/WindowImplWin32.cpp

@@ -55,10 +55,15 @@
     #define MAPVK_VK_TO_VSC (0)
 #endif
 
+// Avoid including <Dbt.h> just for one define
+#ifndef DBT_DEVNODES_CHANGED
+    #define DBT_DEVNODES_CHANGED 0x0007
+#endif
 
 namespace
 {
-    unsigned int               windowCount      = 0;
+    unsigned int               windowCount      = 0; // Windows owned by SFML
+    unsigned int               handleCount      = 0; // All window handles
     const wchar_t*             className        = L"SFML_Window";
     sf::priv::WindowImplWin32* fullscreenWindow = NULL;
 
@@ -141,6 +146,12 @@ m_cursorGrabbed   (false)
 
     if (m_handle)
     {
+        // If we're the first window handle, we only need to poll for joysticks when WM_DEVICECHANGE message is received
+        if (handleCount == 0)
+            JoystickImpl::setLazyUpdates(true);
+
+        ++handleCount;
+
         // We change the event procedure of the control (it is important to save the old one)
         SetWindowLongPtrW(m_handle, GWLP_USERDATA, reinterpret_cast<LONG_PTR>(this));
         m_callback = SetWindowLongPtrW(m_handle, GWLP_WNDPROC, reinterpret_cast<LONG_PTR>(&WindowImplWin32::globalOnEvent));
@@ -202,6 +213,15 @@ m_cursorGrabbed   (m_fullscreen)
     // Create the window
     m_handle = CreateWindowW(className, title.toWideString().c_str(), win32Style, left, top, width, height, NULL, NULL, GetModuleHandle(NULL), this);
 
+    // If we're the first window handle, we only need to poll for joysticks when WM_DEVICECHANGE message is received
+    if (m_handle)
+    {
+        if (handleCount == 0)
+            JoystickImpl::setLazyUpdates(true);
+
+        ++handleCount;
+    }
+    
     // By default, the OS limits the size of the window the the desktop size,
     // we have to resize it after creation to apply the real size
     setSize(Vector2u(mode.width, mode.height));
@@ -222,6 +242,15 @@ WindowImplWin32::~WindowImplWin32()
     if (m_icon)
         DestroyIcon(m_icon);
 
+    // If it's the last window handle we have to poll for joysticks again
+    if (m_handle)
+    {
+        --handleCount;
+
+        if (handleCount == 0)
+            JoystickImpl::setLazyUpdates(false);
+    }
+
     if (!m_callback)
     {
         // Destroy the window
@@ -936,6 +965,13 @@ void WindowImplWin32::processEvent(UINT message, WPARAM wParam, LPARAM lParam)
             pushEvent(event);
             break;
         }
+        case WM_DEVICECHANGE:
+        {
+            // Some sort of device change has happened, update joystick connections
+            if (wParam == DBT_DEVNODES_CHANGED)
+                JoystickImpl::updateConnections();
+            break;
+        }
     }
 }