Fixing camera panning and zooming

Gems/Atom/Tools/MaterialEditor/Code/Include/Atom/Viewport/InputController/MaterialEditorViewportInputControllerBus.h

@@ -53,6 +53,9 @@ namespace MaterialEditor
         //! Modify camera's field of view
         //! @param value field of view in degrees
         virtual void SetFieldOfView(float value) = 0;
+
+        //! Check if camera is looking directly at a model
+        virtual bool IsCameraCentered() const = 0;
     };
 
     using MaterialEditorViewportInputControllerRequestBus = AZ::EBus<MaterialEditorViewportInputControllerRequests>;

Gems/Atom/Tools/MaterialEditor/Code/Source/Viewport/InputController/Behavior.cpp

@@ -76,11 +76,35 @@ namespace MaterialEditor
     void Behavior::TickInternal([[maybe_unused]] float x, [[maybe_unused]] float y, float z)
     {
         m_distanceToTarget = m_distanceToTarget - z;
+
+        bool isCameraCentered = false;
+        MaterialEditorViewportInputControllerRequestBus::BroadcastResult(
+            isCameraCentered,
+            &MaterialEditorViewportInputControllerRequestBus::Handler::IsCameraCentered);
+
+        // if camera is looking at the model (locked to the model) we don't want to zoom past the model's center
+        if (isCameraCentered)
+        {
+            m_distanceToTarget = AZ::GetMax(m_distanceToTarget, 0.0f);
+        }
+
         AZ::Transform transform = AZ::Transform::CreateIdentity();
         AZ::TransformBus::EventResult(transform, m_cameraEntityId, &AZ::TransformBus::Events::GetLocalTM);
         AZ::Vector3 position = m_targetPosition -
             transform.GetRotation().TransformVector(AZ::Vector3::CreateAxisY(m_distanceToTarget));
         AZ::TransformBus::Event(m_cameraEntityId, &AZ::TransformBus::Events::SetLocalTranslation, position);
+
+        // if camera is not locked to the model, move its focal point so we can free look
+        if (!isCameraCentered)
+        {
+            m_targetPosition += transform.GetRotation().TransformVector(AZ::Vector3::CreateAxisY(z));
+            MaterialEditorViewportInputControllerRequestBus::Broadcast(
+                &MaterialEditorViewportInputControllerRequestBus::Handler::SetTargetPosition,
+                m_targetPosition);
+            MaterialEditorViewportInputControllerRequestBus::BroadcastResult(
+                m_distanceToTarget,
+                &MaterialEditorViewportInputControllerRequestBus::Handler::GetDistanceToTarget);
+        }
     }
 
     float Behavior::GetSensitivityX()

Gems/Atom/Tools/MaterialEditor/Code/Source/Viewport/InputController/MaterialEditorViewportInputController.cpp

@@ -96,6 +96,7 @@ namespace MaterialEditor
     void MaterialEditorViewportInputController::SetTargetPosition(const AZ::Vector3& targetPosition)
     {
         m_targetPosition = targetPosition;
+        m_isCameraCentered = false;
     }
 
     float MaterialEditorViewportInputController::GetDistanceToTarget() const
@@ -246,6 +247,7 @@ namespace MaterialEditor
         cameraPosition = cameraRotation.TransformVector(cameraPosition);
         AZ::Transform cameraTransform = AZ::Transform::CreateFromQuaternionAndTranslation(cameraRotation, cameraPosition);
         AZ::TransformBus::Event(m_cameraEntityId, &AZ::TransformBus::Events::SetLocalTM, cameraTransform);
+        m_isCameraCentered = true;
 
         // reset model
         AZ::Transform modelTransform = AZ::Transform::CreateIdentity();
@@ -258,6 +260,12 @@ namespace MaterialEditor
         AZ::RPI::ScenePtr scene = AZ::RPI::RPISystemInterface::Get()->GetDefaultScene();
         auto skyBoxFeatureProcessorInterface = scene->GetFeatureProcessor<AZ::Render::SkyBoxFeatureProcessorInterface>();
         skyBoxFeatureProcessorInterface->SetCubemapRotationMatrix(rotationMatrix);
+
+        if (m_behavior)
+        {
+            m_behavior->End();
+            m_behavior->Start();
+        }
     }
 
     void MaterialEditorViewportInputController::SetFieldOfView(float value)
@@ -265,6 +273,11 @@ namespace MaterialEditor
         Camera::CameraRequestBus::Event(m_cameraEntityId, &Camera::CameraRequestBus::Events::SetFovDegrees, value);
     }
 
+    bool MaterialEditorViewportInputController::IsCameraCentered() const
+    {
+        return m_isCameraCentered;
+    }
+
     void MaterialEditorViewportInputController::CalculateExtents()
     {
         AZ::TransformBus::EventResult(m_modelCenter, m_targetEntityId, &AZ::TransformBus::Events::GetLocalTranslation);

Gems/Atom/Tools/MaterialEditor/Code/Source/Viewport/InputController/MaterialEditorViewportInputController.h

@@ -45,6 +45,7 @@ namespace MaterialEditor
         void GetExtents(float& distanceMin, float& distanceMax) const override;
         void Reset() override;
         void SetFieldOfView(float value) override;
+        bool IsCameraCentered() const override;
 
         // AzFramework::ViewportControllerInstance interface overrides...
         bool HandleInputChannelEvent(const AzFramework::ViewportControllerInputEvent& event) override;
@@ -95,6 +96,8 @@ namespace MaterialEditor
         float m_distanceMin = 1.0f;
         //! Maximum distance from camera to target
         float m_distanceMax = 10.0f;
+        //! True if camera is centered on a model
+        bool m_isCameraCentered = true;
 
         static constexpr float MaxDistanceMultiplier = 2.5f;
         static constexpr float StartingDistanceMultiplier = 2.0f;

Gems/Atom/Tools/MaterialEditor/Code/Source/Viewport/InputController/PanCameraBehavior.cpp

@@ -34,10 +34,8 @@ namespace MaterialEditor
             targetPosition);
     }
 
-    void PanCameraBehavior::TickInternal(float x, float y, float z)
+    void PanCameraBehavior::TickInternal(float x, float y, [[maybe_unused]] float z)
     {
-        Behavior::TickInternal(x, y, z);
-
         AZ::Transform transform = AZ::Transform::CreateIdentity();
         AZ::TransformBus::EventResult(transform, m_cameraEntityId, &AZ::TransformBus::Events::GetLocalTM);
         AZ::Quaternion rotation = transform.GetRotation();