1 files changed, 41 insertions, 11 deletions

diff --git a/Source/Core/InputCommon/ControllerInterface/DInput/DInput.cpp b/Source/Core/InputCommon/ControllerInterface/DInput/DInput.cpp
index d508de613a..f5e105dc45 100644
--- a/Source/Core/InputCommon/ControllerInterface/DInput/DInput.cpp
+++ b/Source/Core/InputCommon/ControllerInterface/DInput/DInput.cpp
@@ -16,6 +16,8 @@
 
 namespace ciface::DInput
 {
+static IDirectInput8* s_idi8 = nullptr;
+
 BOOL CALLBACK DIEnumDeviceObjectsCallback(LPCDIDEVICEOBJECTINSTANCE lpddoi, LPVOID pvRef)
 {
   ((std::list<DIDEVICEOBJECTINSTANCE>*)pvRef)->push_back(*lpddoi);
@@ -42,29 +44,57 @@ std::string GetDeviceName(const LPDIRECTINPUTDEVICE8 device)
   }
   else
   {
-    ERROR_LOG_FMT(PAD, "GetProperty(DIPROP_PRODUCTNAME) failed.");
+    ERROR_LOG_FMT(CONTROLLERINTERFACE, "GetProperty(DIPROP_PRODUCTNAME) failed.");
   }
 
   return result;
 }
 
+// Assumes hwnd had not changed from the previous call
 void PopulateDevices(HWND hwnd)
 {
-  // Remove unplugged devices.
+  if (!s_idi8 && FAILED(DirectInput8Create(GetModuleHandle(nullptr), DIRECTINPUT_VERSION,
+                                           IID_IDirectInput8, (LPVOID*)&s_idi8, nullptr)))
+  {
+    ERROR_LOG_FMT(CONTROLLERINTERFACE, "DirectInput8Create failed.");
+    return;
+  }
+
+  // Remove old (invalid) devices. No need to ever remove the KeyboardMouse device.
+  // Note that if we have 2+ DInput controllers, not fully repopulating devices
+  // will mean that a device with index "2" could persist while there is no device with index "0".
+  // This is slightly inconsistent as when we refresh all devices, they will instead reset, and
+  // that happens a lot (for uncontrolled reasons, like starting/stopping the emulation).
   g_controller_interface.RemoveDevice(
       [](const auto* dev) { return dev->GetSource() == DINPUT_SOURCE_NAME && !dev->IsValid(); });
 
-  IDirectInput8* idi8;
-  if (FAILED(DirectInput8Create(GetModuleHandle(nullptr), DIRECTINPUT_VERSION, IID_IDirectInput8,
-                                (LPVOID*)&idi8, nullptr)))
+  InitKeyboardMouse(s_idi8, hwnd);
+  InitJoystick(s_idi8, hwnd);
+}
+
+void ChangeWindow(HWND hwnd)
+{
+  if (s_idi8)  // Has init? Ignore if called before the first PopulateDevices()
   {
-    ERROR_LOG_FMT(PAD, "DirectInput8Create failed.");
-    return;
-  }
+    // The KeyboardMouse device is marked as virtual device, so we avoid removing it.
+    // We need to force all the DInput joysticks to be destroyed now, or recreation would fail.
+    g_controller_interface.RemoveDevice(
+        [](const auto* dev) {
+          return dev->GetSource() == DINPUT_SOURCE_NAME && !dev->IsVirtualDevice();
+        },
+        true);
 
-  InitKeyboardMouse(idi8, hwnd);
-  InitJoystick(idi8, hwnd);
+    SetKeyboardMouseWindow(hwnd);
+    InitJoystick(s_idi8, hwnd);
+  }
+}
 
-  idi8->Release();
+void DeInit()
+{
+  if (s_idi8)
+  {
+    s_idi8->Release();
+    s_idi8 = nullptr;
+  }
 }
 }  // namespace ciface::DInput