ControllerInterface: Implement ChangeWindow on DInput without recreating the devices

Also polished DInput code in general to try and mitigate issue 11702.
Added a lot of logging and comments.

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.
-  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)))
+  if (!s_idi8 && FAILED(DirectInput8Create(GetModuleHandle(nullptr), DIRECTINPUT_VERSION,
+                                           IID_IDirectInput8, (LPVOID*)&s_idi8, nullptr)))
   {
-    ERROR_LOG_FMT(PAD, "DirectInput8Create failed.");
+    ERROR_LOG_FMT(CONTROLLERINTERFACE, "DirectInput8Create failed.");
     return;
   }
 
-  InitKeyboardMouse(idi8, hwnd);
-  InitJoystick(idi8, hwnd);
+  // 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(); });
 
-  idi8->Release();
+  InitKeyboardMouse(s_idi8, hwnd);
+  InitJoystick(s_idi8, hwnd);
+}
+
+void ChangeWindow(HWND hwnd)
+{
+  if (s_idi8)  // Has init? Ignore if called before the first PopulateDevices()
+  {
+    // 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);
+
+    SetKeyboardMouseWindow(hwnd);
+    InitJoystick(s_idi8, hwnd);
+  }
+}
+
+void DeInit()
+{
+  if (s_idi8)
+  {
+    s_idi8->Release();
+    s_idi8 = nullptr;
+  }
 }
 }  // namespace ciface::DInput

Source/Core/InputCommon/ControllerInterface/DInput/DInput.h

@@ -20,4 +20,6 @@ BOOL CALLBACK DIEnumDevicesCallback(LPCDIDEVICEINSTANCE lpddi, LPVOID pvRef);
 std::string GetDeviceName(const LPDIRECTINPUTDEVICE8 device);
 
 void PopulateDevices(HWND hwnd);
+void ChangeWindow(HWND hwnd);
+void DeInit();
 }  // namespace ciface::DInput

Source/Core/InputCommon/ControllerInterface/DInput/DInputKeyboardMouse.cpp

@@ -6,7 +6,8 @@
 
 #include <algorithm>
 
-#include <fmt/format.h>
+#include "Common/Logging/Log.h"
+#include "Core/Core.h"
 
 #include "InputCommon/ControllerInterface/ControllerInterface.h"
 #include "InputCommon/ControllerInterface/DInput/DInput.h"
@@ -54,15 +55,18 @@ static const struct
 #include "InputCommon/ControllerInterface/DInput/NamedKeys.h"  // NOLINT
 };
 
-// Prevent duplicate keyboard/mouse devices.
-static bool s_keyboard_mouse_exists = false;
+// Prevent duplicate keyboard/mouse devices. Modified by more threads.
+static bool s_keyboard_mouse_exists;
+static HWND s_hwnd;
 
 void InitKeyboardMouse(IDirectInput8* const idi8, HWND hwnd)
 {
   if (s_keyboard_mouse_exists)
     return;
 
-  // mouse and keyboard are a combined device, to allow shift+click and stuff
+  s_hwnd = hwnd;
+
+  // Mouse and keyboard are a combined device, to allow shift+click and stuff
   // if that's dumb, I will make a VirtualDevice class that just uses ranges of inputs/outputs from
   // other devices
   // so there can be a separated Keyboard and mouse, as well as combined KeyboardMouse
@@ -70,6 +74,8 @@ void InitKeyboardMouse(IDirectInput8* const idi8, HWND hwnd)
   LPDIRECTINPUTDEVICE8 kb_device = nullptr;
   LPDIRECTINPUTDEVICE8 mo_device = nullptr;
 
+  // These are "virtual" system devices, so they are always there even if we have no physical
+  // mouse and keyboard plugged into the computer
   if (SUCCEEDED(idi8->CreateDevice(GUID_SysKeyboard, &kb_device, nullptr)) &&
       SUCCEEDED(kb_device->SetDataFormat(&c_dfDIKeyboard)) &&
       SUCCEEDED(kb_device->SetCooperativeLevel(nullptr, DISCL_BACKGROUND | DISCL_NONEXCLUSIVE)) &&
@@ -77,16 +83,23 @@ void InitKeyboardMouse(IDirectInput8* const idi8, HWND hwnd)
       SUCCEEDED(mo_device->SetDataFormat(&c_dfDIMouse2)) &&
       SUCCEEDED(mo_device->SetCooperativeLevel(nullptr, DISCL_BACKGROUND | DISCL_NONEXCLUSIVE)))
   {
-    g_controller_interface.AddDevice(std::make_shared<KeyboardMouse>(kb_device, mo_device, hwnd));
+    g_controller_interface.AddDevice(std::make_shared<KeyboardMouse>(kb_device, mo_device));
     return;
   }
 
+  ERROR_LOG_FMT(CONTROLLERINTERFACE, "KeyboardMouse device failed to be created");
+
   if (kb_device)
     kb_device->Release();
   if (mo_device)
     mo_device->Release();
 }
 
+void SetKeyboardMouseWindow(HWND hwnd)
+{
+  s_hwnd = hwnd;
+}
+
 KeyboardMouse::~KeyboardMouse()
 {
   s_keyboard_mouse_exists = false;
@@ -105,9 +118,8 @@ KeyboardMouse::~KeyboardMouse()
 }
 
 KeyboardMouse::KeyboardMouse(const LPDIRECTINPUTDEVICE8 kb_device,
-                             const LPDIRECTINPUTDEVICE8 mo_device, HWND hwnd)
-    : m_kb_device(kb_device), m_mo_device(mo_device), m_hwnd(hwnd), m_last_update(GetTickCount()),
-      m_state_in()
+                             const LPDIRECTINPUTDEVICE8 mo_device)
+    : m_kb_device(kb_device), m_mo_device(mo_device), m_last_update(GetTickCount()), m_state_in()
 {
   s_keyboard_mouse_exists = true;
 
@@ -160,11 +172,11 @@ void KeyboardMouse::UpdateCursorInput()
 
   // Get the cursor position relative to the upper left corner of the current window
   // (separate or render to main)
-  ScreenToClient(m_hwnd, &point);
+  ScreenToClient(s_hwnd, &point);
 
-  // Get the size of the current window. (In my case Rect.top and Rect.left was zero.)
+  // Get the size of the current window (in my case Rect.top and Rect.left was zero).
   RECT rect;
-  GetClientRect(m_hwnd, &rect);
+  GetClientRect(s_hwnd, &rect);
 
   // Width and height are the size of the rendering window. They could be 0
   const auto win_width = std::max(rect.right - rect.left, 1l);
@@ -236,6 +248,11 @@ int KeyboardMouse::GetSortPriority() const
   return 5;
 }
 
+bool KeyboardMouse::IsVirtualDevice() const
+{
+  return true;
+}
+
 // names
 std::string KeyboardMouse::Key::GetName() const
 {

Source/Core/InputCommon/ControllerInterface/DInput/DInputKeyboardMouse.h

@@ -16,6 +16,7 @@ namespace ciface::DInput
 void InitKeyboardMouse(IDirectInput8* const idi8, HWND hwnd);
 
 using RelativeMouseState = RelativeInputState<Common::TVec3<LONG>>;
+void SetKeyboardMouseWindow(HWND hwnd);
 
 class KeyboardMouse : public Core::Device
 {
@@ -96,13 +97,13 @@ private:
 public:
   void UpdateInput() override;
 
-  KeyboardMouse(const LPDIRECTINPUTDEVICE8 kb_device, const LPDIRECTINPUTDEVICE8 mo_device,
-                HWND hwnd);
+  KeyboardMouse(const LPDIRECTINPUTDEVICE8 kb_device, const LPDIRECTINPUTDEVICE8 mo_device);
   ~KeyboardMouse();
 
   std::string GetName() const override;
   std::string GetSource() const override;
   int GetSortPriority() const override;
+  bool IsVirtualDevice() const override;
 
 private:
   void UpdateCursorInput();
@@ -110,8 +111,6 @@ private:
   const LPDIRECTINPUTDEVICE8 m_kb_device;
   const LPDIRECTINPUTDEVICE8 m_mo_device;
 
-  const HWND m_hwnd;
-
   DWORD m_last_update;
   State m_state_in;
 };