Fix mouse capture behavior for Editor Viewport (#3417)

* first pass of fixes for cursor capture and context menu

Signed-off-by: hultonha <hultonha@amazon.co.uk>

* restore previous behavior of HandleMouseMoveEvent

Signed-off-by: hultonha <hultonha@amazon.co.uk>

* tidy-up from previous cursor/input changes

Signed-off-by: hultonha <hultonha@amazon.co.uk>

* add missing casts

Signed-off-by: hultonha <hultonha@amazon.co.uk>

* small updates to support tests

Signed-off-by: hultonha <hultonha@amazon.co.uk>

* additional tests and some tidy-up

Signed-off-by: hultonha <hultonha@amazon.co.uk>

* small updates before publishing PR (comment/naming updates)

Signed-off-by: hultonha <hultonha@amazon.co.uk>

* add missing parameter to MouseInteractionEvent constructor

Signed-off-by: hultonha <hultonha@amazon.co.uk>

Code/Framework/AzFramework/AzFramework/Viewport/CameraInput.cpp

@@ -144,6 +144,7 @@ namespace AzFramework
         if (const auto& cursor = AZStd::get_if<CursorEvent>(&event))
         {
             m_cursorState.SetCurrentPosition(cursor->m_position);
+            m_cursorState.SetCaptured(cursor->m_captured);
         }
         else if (const auto& horizontalMotion = AZStd::get_if<HorizontalMotionEvent>(&event))
         {
@@ -790,17 +791,24 @@ namespace AzFramework
                 const auto* position = inputChannel.GetCustomData<AzFramework::InputChannel::PositionData2D>();
                 AZ_Assert(position, "Expected PositionData2D but found nullptr");
 
-                return CursorEvent{ ScreenPoint(
-                    static_cast<int>(position->m_normalizedPosition.GetX() * windowSize.m_width),
-                    static_cast<int>(position->m_normalizedPosition.GetY() * windowSize.m_height)) };
+                auto currentCursorState = AzFramework::SystemCursorState::Unknown;
+                AzFramework::InputSystemCursorRequestBus::EventResult(
+                    currentCursorState, inputDeviceId, &AzFramework::InputSystemCursorRequestBus::Events::GetSystemCursorState);
+
+                const auto x = position->m_normalizedPosition.GetX() * aznumeric_cast<float>(windowSize.m_width);
+                const auto y = position->m_normalizedPosition.GetY() * aznumeric_cast<float>(windowSize.m_height);
+                return CursorEvent{ ScreenPoint(aznumeric_cast<int>(AZStd::lround(x)), aznumeric_cast<int>(AZStd::lround(y))),
+                                    currentCursorState == AzFramework::SystemCursorState::ConstrainedAndHidden };
             }
             else if (inputChannelId == InputDeviceMouse::Movement::X)
             {
-                return HorizontalMotionEvent{ aznumeric_cast<int>(inputChannel.GetValue()) };
+                const auto x = inputChannel.GetValue();
+                return HorizontalMotionEvent{ aznumeric_cast<int>(AZStd::lround(x)) };
             }
             else if (inputChannelId == InputDeviceMouse::Movement::Y)
             {
-                return VerticalMotionEvent{ aznumeric_cast<int>(inputChannel.GetValue()) };
+                const auto y = inputChannel.GetValue();
+                return VerticalMotionEvent{ aznumeric_cast<int>(AZStd::lround(y)) };
             }
             else if (inputChannelId == InputDeviceMouse::Movement::Z)
             {

Code/Framework/AzFramework/AzFramework/Viewport/CameraInput.h

@@ -88,6 +88,7 @@ namespace AzFramework
     struct CursorEvent
     {
         ScreenPoint m_position;
+        bool m_captured = false;
     };
 
     struct ScrollEvent

Code/Framework/AzFramework/AzFramework/Viewport/CursorState.h

@@ -21,6 +21,8 @@ namespace AzFramework
         [[nodiscard]] ScreenVector CursorDelta() const;
         //! Call this in a 'handle event' call to update the most recent cursor position.
         void SetCurrentPosition(const ScreenPoint& currentPosition);
+        //! Set whether the cursor is currently being constrained (and hidden).
+        void SetCaptured(bool captured);
         //! Call this in an 'update' call to copy the current cursor position to the last
         //! cursor position.
         void Update();
@@ -28,8 +30,14 @@ namespace AzFramework
     private:
         AZStd::optional<ScreenPoint> m_lastCursorPosition;
         AZStd::optional<ScreenPoint> m_currentCursorPosition;
+        bool m_captured = false;
     };
 
+    inline void CursorState::SetCaptured(const bool captured)
+    {
+        m_captured = captured;
+    }
+
     inline void CursorState::SetCurrentPosition(const ScreenPoint& currentPosition)
     {
         m_currentCursorPosition = currentPosition;
@@ -44,9 +52,16 @@ namespace AzFramework
 
     inline void CursorState::Update()
     {
-        if (m_currentCursorPosition.has_value())
+        if (!m_captured)
         {
-            m_lastCursorPosition = m_currentCursorPosition;
+            if (m_currentCursorPosition.has_value())
+            {
+                m_lastCursorPosition = m_currentCursorPosition;
+            }
+        }
+        else
+        {
+            m_currentCursorPosition = m_lastCursorPosition;
         }
     }
 } // namespace AzFramework