[Linux] Unify Editor and Game raw mouse event handling

Signed-off-by: Chris Burel <burelc@amazon.com>

Code/Editor/Platform/Linux/Editor/Core/QtEditorApplication_linux.cpp

@@ -10,6 +10,8 @@
 
 #ifdef PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
 #include <AzFramework/XcbEventHandler.h>
+#include <AzFramework/XcbConnectionManager.h>
+#include <qpa/qplatformnativeinterface.h>
 #endif
 
 namespace Editor
@@ -23,16 +25,34 @@ namespace Editor
         return nullptr;
     }
 
+    xcb_connection_t* EditorQtApplicationXcb::GetXcbConnectionFromQt()
+    {
+        QPlatformNativeInterface* native = platformNativeInterface();
+        AZ_Warning("EditorQtApplicationXcb", native, "Unable to retrieve the native platform interface");
+        if (!native)
+        {
+            return nullptr;
+        }
+        return reinterpret_cast<xcb_connection_t*>(native->nativeResourceForIntegration(QByteArray("connection")));
+    }
+
+    void EditorQtApplicationXcb::OnStartPlayInEditor()
+    {
+        auto* interface = AzFramework::XcbConnectionManagerInterface::Get();
+        interface->SetEnableXInput(GetXcbConnectionFromQt(), true);
+    }
+
+    void EditorQtApplicationXcb::OnStopPlayInEditor()
+    {
+        auto* interface = AzFramework::XcbConnectionManagerInterface::Get();
+        interface->SetEnableXInput(GetXcbConnectionFromQt(), false);
+    }
+
     bool EditorQtApplicationXcb::nativeEventFilter([[maybe_unused]] const QByteArray& eventType, void* message, long*)
     {
         if (GetIEditor()->IsInGameMode())
         {
 #ifdef PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
-            // We need to handle RAW Input events in a separate loop. This is a workaround to enable XInput2 RAW Inputs using Editor mode.
-            // TODO To have this call here might be not be perfect.
-            AzFramework::XcbEventHandlerBus::Broadcast(&AzFramework::XcbEventHandler::PollSpecialEvents);
-
-            // Now handle the rest of the events.
             AzFramework::XcbEventHandlerBus::Broadcast(
                 &AzFramework::XcbEventHandler::HandleXcbEvent, static_cast<xcb_generic_event_t*>(message));
 #endif

Code/Editor/Platform/Linux/Editor/Core/QtEditorApplication_linux.h

@@ -6,19 +6,35 @@
  *
  */
 
+#if !defined(Q_MOC_RUN)
 #include <Editor/Core/QtEditorApplication.h>
+#include <AzToolsFramework/Entity/EditorEntityContextBus.h>
+#endif
+
+using xcb_connection_t = struct xcb_connection_t;
 
 namespace Editor
 {
-    class EditorQtApplicationXcb : public EditorQtApplication
+    class EditorQtApplicationXcb
+        : public EditorQtApplication
+        , public AzToolsFramework::EditorEntityContextNotificationBus::Handler
     {
         Q_OBJECT
     public:
         EditorQtApplicationXcb(int& argc, char** argv)
             : EditorQtApplication(argc, argv)
         {
+            // Connect bus to listen for OnStart/StopPlayInEditor events
+            AzToolsFramework::EditorEntityContextNotificationBus::Handler::BusConnect();
         }
 
+        xcb_connection_t* GetXcbConnectionFromQt();
+
+        ///////////////////////////////////////////////////////////////////////
+        // AzToolsFramework::EditorEntityContextNotificationBus overrides
+        void OnStartPlayInEditor() override;
+        void OnStopPlayInEditor() override;
+
         // QAbstractNativeEventFilter:
         bool nativeEventFilter(const QByteArray& eventType, void* message, long* result) override;
     };