Update modular viewport camera controller interface (#6282)

* update modular viewport camera controller interface to make follow behaviors easier

Signed-off-by: Tom Hulton-Harrop <82228511+hultonha@users.noreply.github.com>

* updates following PR feedback

Signed-off-by: Tom Hulton-Harrop <82228511+hultonha@users.noreply.github.com>

Gems/Atom/Tools/AtomToolsFramework/Code/Include/AtomToolsFramework/Viewport/ModularViewportCameraController.h

@@ -117,6 +117,9 @@ namespace AtomToolsFramework
         void StartTrackingTransform(const AZ::Transform& worldFromLocal) override;
         void StopTrackingTransform() override;
         bool IsTrackingTransform() const override;
+        void SetCameraPivotAttached(const AZ::Vector3& pivot) override;
+        void SetCameraPivotDetached(const AZ::Vector3& pivot) override;
+        void SetCameraOffset(const AZ::Vector3& offset) override;
 
     private:
         //! Combine the current camera transform with any potential roll from the tracked

Gems/Atom/Tools/AtomToolsFramework/Code/Include/AtomToolsFramework/Viewport/ModularViewportCameraControllerRequestBus.h

@@ -29,25 +29,31 @@ namespace AtomToolsFramework
         static const AZ::EBusAddressPolicy AddressPolicy = AZ::EBusAddressPolicy::ById;
         static const AZ::EBusHandlerPolicy HandlerPolicy = AZ::EBusHandlerPolicy::Single;
 
-        //! Begin a smooth transition of the camera to the requested transform.
+        //! Begins a smooth transition of the camera to the requested transform.
         //! @param worldFromLocal The transform of where the camera should end up.
         //! @return Returns true if the call began an interpolation and false otherwise. Calls to InterpolateToTransform
         //! will have no effect if an interpolation is currently in progress.
         virtual bool InterpolateToTransform(const AZ::Transform& worldFromLocal) = 0;
-
         //! Returns if the camera is currently interpolating to a new transform.
         virtual bool IsInterpolating() const = 0;
-
-        //! Start tracking a transform.
+        //! Starts tracking a transform.
         //! Store the current camera transform and move to the next camera transform.
         virtual void StartTrackingTransform(const AZ::Transform& worldFromLocal) = 0;
-
-        //! Stop tracking the set transform.
+        //! Stops tracking the set transform.
         //! The previously stored camera transform is restored.
         virtual void StopTrackingTransform() = 0;
-
-        //! Return if the tracking transform is set.
+        //! Returns if the tracking transform is set.
         virtual bool IsTrackingTransform() const = 0;
+        //! Sets the current camera pivot, moving the camera offset with it (the camera appears
+        //! to follow the pivot, staying the same distance away from it).
+        virtual void SetCameraPivotAttached(const AZ::Vector3& pivot) = 0;
+        //! Sets the current camera pivot, leaving the camera offset in-place (the camera will
+        //! stay fixed and the pivot will appear to move around on its own).
+        virtual void SetCameraPivotDetached(const AZ::Vector3& pivot) = 0;
+        //! Sets the current camera offset from the pivot.
+        //! @note The offset value is in the current space of the camera, not world space. Setting
+        //! a negative Z value will move the camera backwards from the pivot.
+        virtual void SetCameraOffset(const AZ::Vector3& offset) = 0;
 
     protected:
         ~ModularViewportCameraControllerRequests() = default;

Gems/Atom/Tools/AtomToolsFramework/Code/Source/Viewport/ModularViewportCameraController.cpp

@@ -279,6 +279,21 @@ namespace AtomToolsFramework
         return false;
     }
 
+    void ModularViewportCameraControllerInstance::SetCameraPivotAttached(const AZ::Vector3& pivot)
+    {
+        m_targetCamera.m_pivot = pivot;
+    }
+
+    void ModularViewportCameraControllerInstance::SetCameraPivotDetached(const AZ::Vector3& pivot)
+    {
+        AzFramework::MovePivotDetached(m_targetCamera, pivot);
+    }
+
+    void ModularViewportCameraControllerInstance::SetCameraOffset(const AZ::Vector3& offset)
+    {
+        m_targetCamera.m_offset = offset;
+    }
+
     bool ModularViewportCameraControllerInstance::IsInterpolating() const
     {
         return m_cameraMode == CameraMode::Animation;

Gems/AtomLyIntegration/EMotionFXAtom/Code/Tools/EMStudio/AnimViewportWidget.cpp

@@ -170,11 +170,32 @@ namespace EMStudio
                 targetPosition.GetX() - CameraDistance, targetPosition.GetY() + CameraDistance, targetPosition.GetZ() + CameraDistance);
             break;
         }
+
         GetViewportContext()->SetCameraTransform(AZ::Transform::CreateLookAt(cameraPosition, targetPosition));
+
+        AtomToolsFramework::ModularViewportCameraControllerRequestBus::Event(
+            GetViewportId(), &AtomToolsFramework::ModularViewportCameraControllerRequestBus::Events::SetCameraOffset,
+            AZ::Vector3::CreateAxisY(-CameraDistance));
     }
 
     void AnimViewportWidget::SetFollowCharacter(bool follow)
     {
+        if (follow)
+        {
+            AtomToolsFramework::ModularViewportCameraControllerRequestBus::Event(
+                GetViewportId(), &AtomToolsFramework::ModularViewportCameraControllerRequestBus::Events::SetCameraOffset,
+                AZ::Vector3::CreateAxisY(-CameraDistance));
+        }
+        else
+        {
+            AtomToolsFramework::ModularViewportCameraControllerRequestBus::Event(
+                GetViewportId(), &AtomToolsFramework::ModularViewportCameraControllerRequestBus::Events::SetCameraOffset,
+                AZ::Vector3::CreateZero());
+            AtomToolsFramework::ModularViewportCameraControllerRequestBus::Event(
+                GetViewportId(), &AtomToolsFramework::ModularViewportCameraControllerRequestBus::Events::SetCameraPivotAttached,
+                GetViewportContext()->GetCameraTransform().GetTranslation());
+        }
+
         m_followCharacter = follow;
     }
 
@@ -190,7 +211,7 @@ namespace EMStudio
     {
         auto viewportContext = GetViewportContext();
         auto windowSize = viewportContext->GetViewportSize();
-        // Prevent devided by zero
+        // Prevent division by zero
         const float height = AZStd::max<float>(aznumeric_cast<float>(windowSize.m_height), 1.0f);
         const float aspectRatio = aznumeric_cast<float>(windowSize.m_width) / height;
 
@@ -216,14 +237,10 @@ namespace EMStudio
     {
         if (m_followCharacter)
         {
-            // When follow charater move is enabled, we are adding the delta of the character movement to the camera per frame.
-            AZ::Vector3 camPos = GetViewportContext()->GetCameraTransform().GetTranslation();
-            camPos += m_renderer->GetCharacterCenter() - m_prevCharacterPos;
-            AZ::Transform newCamTransform = GetViewportContext()->GetCameraTransform();
-            newCamTransform.SetTranslation(camPos);
-            GetViewportContext()->SetCameraTransform(newCamTransform);
+            AtomToolsFramework::ModularViewportCameraControllerRequestBus::Event(
+                GetViewportId(), &AtomToolsFramework::ModularViewportCameraControllerRequestBus::Events::SetCameraPivotAttached,
+                m_renderer->GetCharacterCenter());
         }
-        m_prevCharacterPos = m_renderer->GetCharacterCenter();
     }
 
     void AnimViewportWidget::ToggleRenderFlag(EMotionFX::ActorRenderFlag flag)

Gems/AtomLyIntegration/EMotionFXAtom/Code/Tools/EMStudio/AnimViewportWidget.h

@@ -64,6 +64,5 @@ namespace EMStudio
         AZStd::shared_ptr<AzFramework::OrbitDollyScrollCameraInput> m_orbitDollyScrollCamera;
         EMotionFX::ActorRenderFlagBitset m_renderFlags;
         bool m_followCharacter = false;
-        AZ::Vector3 m_prevCharacterPos;
     };
 }