// Copyright 1998-2015 Epic Games, Inc. All Rights Reserved.


#include "LevelEditor.h"
#include "SLevelViewport.h"
#include "SLevelViewportToolBar.h"
#include "Editor/UnrealEd/Public/STransformViewportToolbar.h"
#include "LevelViewportLayout.h"
#include "LevelViewportTabContent.h"
#include "Runtime/Engine/Public/Slate/SceneViewport.h"
#include "EditorShowFlags.h"
#include "LevelViewportActions.h"
#include "SLevelEditor.h"
#include "AssetSelection.h"
#include "LevelEditorActions.h"
#include "Editor/UnrealEd/Public/Kismet2/DebuggerCommands.h"
#include "Layers/ILayers.h"
#include "Editor/UnrealEd/Public/DragAndDrop/ClassDragDropOp.h"
#include "Editor/UnrealEd/Public/DragAndDrop/AssetDragDropOp.h"
#include "Editor/UnrealEd/Public/DragAndDrop/ExportTextDragDropOp.h"
#include "Editor/UnrealEd/Public/DragAndDrop/BrushBuilderDragDropOp.h"
#include "Editor/SceneOutliner/Public/SceneOutliner.h"
#include "ScopedTransaction.h"
#include "LevelUtils.h"
#include "HighresScreenshotUI.h"
#include "SCaptureRegionWidget.h"
#include "ISettingsModule.h"
#include "BufferVisualizationData.h"
#include "EditorViewportCommands.h"
#include "Runtime/Engine/Classes/Engine/UserInterfaceSettings.h"
#include "Runtime/Engine/Classes/Engine/RendererSettings.h"
#include "SNotificationList.h"
#include "NotificationManager.h"
#include "SLevelViewportControlsPopup.h"
#include "Camera/CameraActor.h"
#include "GameFramework/WorldSettings.h"
#include "Engine/LocalPlayer.h"
#include "Engine/Selection.h"
#include "GameFramework/PlayerInput.h"
#include "GameFramework/PlayerController.h"
#include "SActorPilotViewportToolbar.h"
#include "SGameLayerManager.h"

static const FName LevelEditorName("LevelEditor");

#define LOCTEXT_NAMESPACE "LevelViewport"

// @todo Slate Hack: Disallow game UI to be used in play in viewport until GWorld problem is fixed
// Currently Slate has no knowledge of a world and cannot switch it before input events,etc
#define ALLOW_PLAY_IN_VIEWPORT_GAMEUI 1

namespace SLevelViewportPIEAnimation
{
	float const MouseControlLabelFadeout = 5.0f;
}

class FLevelViewportDropContextMenuImpl
{
public:
	/**
	 * Fills in menu options for the actor add/replacement submenu
	 *
	 * @param bReplace		true if we want to add a replace menu instead of add
	 * @param MenuBuilder	The menu to add items to
	 */
	static void FillDropAddReplaceActorMenu( bool bReplace, class FMenuBuilder& MenuBuilder );
};


SLevelViewport::SLevelViewport()
	: HighResScreenshotDialog( NULL )
	, ViewTransitionType( EViewTransition::None )
	, bViewTransitionAnimPending( false )
	, DeviceProfile("Default")
	, PIEOverlaySlotIndex(0)
	, bPIEHasFocus(false)
	, bPIEContainsFocus(false)
	, UserAllowThrottlingValue(0)
{
}

SLevelViewport::~SLevelViewport()
{
	// Clean up any actor preview viewports
	for (FViewportActorPreview& ActorPreview : ActorPreviews)
	{
		ActorPreview.bIsPinned = false;
	}
	PreviewActors( TArray< AActor* >() );

	FLevelViewportCommands::NewStatCommandDelegate.RemoveAll(this);

	FLevelEditorModule& LevelEditor = FModuleManager::GetModuleChecked<FLevelEditorModule>( LevelEditorName );
	LevelEditor.OnRedrawLevelEditingViewports().RemoveAll( this );
	LevelEditor.OnTakeHighResScreenShots().RemoveAll( this );
	LevelEditor.OnActorSelectionChanged().RemoveAll( this );
	LevelEditor.OnMapChanged().RemoveAll( this );
	GEngine->OnLevelActorDeleted().RemoveAll( this );

	GetMutableDefault<ULevelEditorViewportSettings>()->OnSettingChanged().RemoveAll( this );

	// If this viewport has a high res screenshot window attached to it, close it
	if (HighResScreenshotDialog.IsValid())
	{
		HighResScreenshotDialog.Pin()->RequestDestroyWindow();
		HighResScreenshotDialog.Reset();
	}
}

void SLevelViewport::HandleViewportSettingChanged(FName PropertyName)
{
	if ( PropertyName == TEXT("bPreviewSelectedCameras") )
	{
		OnPreviewSelectedCamerasChange();
	}
}

bool SLevelViewport::IsVisible() const
{
	// The viewport is visible if we don't have a parent layout (likely a floating window) or this viewport is visible in the parent layout
	return IsInForegroundTab() && SEditorViewport::IsVisible();
}

bool SLevelViewport::IsInForegroundTab() const
{
	return ViewportWidget.IsValid() && (!ParentLayout.IsValid() || ParentLayout.Pin()->IsLevelViewportVisible(*this));
}

void SLevelViewport::Construct(const FArguments& InArgs)
{
	GetMutableDefault<ULevelEditorViewportSettings>()->OnSettingChanged().AddRaw(this, &SLevelViewport::HandleViewportSettingChanged);

	ParentLayout = InArgs._ParentLayout;
	ParentLevelEditor = InArgs._ParentLevelEditor;
	ConfigKey = InArgs._ConfigKey;

	// Store border brushes for differentiating between active and inactive viewports
	ActiveBorder = FEditorStyle::GetBrush( "LevelViewport.ActiveViewportBorder" );
	NoBorder = FEditorStyle::GetBrush( "LevelViewport.NoViewportBorder" );
	DebuggingBorder = FEditorStyle::GetBrush( "LevelViewport.DebugBorder" );
	BlackBackground = FEditorStyle::GetBrush( "LevelViewport.BlackBackground" );
	StartingPlayInEditorBorder = FEditorStyle::GetBrush( "LevelViewport.StartingPlayInEditorBorder" );
	StartingSimulateBorder = FEditorStyle::GetBrush( "LevelViewport.StartingSimulateBorder" );
	ReturningToEditorBorder = FEditorStyle::GetBrush( "LevelViewport.ReturningToEditorBorder" );


	ConstructLevelEditorViewportClient( InArgs );

	SEditorViewport::Construct( SEditorViewport::FArguments() );

	ActiveViewport = SceneViewport;

	ConstructViewportOverlayContent();


	// If a map has already been loaded, this will test for it and copy the correct camera location out
	OnMapChanged( GWorld, EMapChangeType::LoadMap );

	// Important: We use raw bindings here because we are releasing our binding in our destructor (where a weak pointer would be invalid)
	// It's imperative that our delegate is removed in the destructor for the level editor module to play nicely with reloading.

	FLevelEditorModule& LevelEditor = FModuleManager::GetModuleChecked<FLevelEditorModule>( LevelEditorName );
	LevelEditor.OnRedrawLevelEditingViewports().AddRaw( this, &SLevelViewport::RedrawViewport );
	LevelEditor.OnTakeHighResScreenShots().AddRaw( this, &SLevelViewport::TakeHighResScreenShot );

	// Tell the level editor we want to be notified when selection changes
	LevelEditor.OnActorSelectionChanged().AddRaw( this, &SLevelViewport::OnActorSelectionChanged );

	// Tell the level editor we want to be notified when selection changes
	LevelEditor.OnMapChanged().AddRaw( this, &SLevelViewport::OnMapChanged );

	GEngine->OnLevelActorDeleted().AddRaw( this, &SLevelViewport::OnLevelActorsRemoved );
}

void SLevelViewport::ConstructViewportOverlayContent()
{
	PIEViewportOverlayWidget = SNew( SOverlay );

	int32 SlotIndex = 0;
#if ALLOW_PLAY_IN_VIEWPORT_GAMEUI
		ViewportOverlay->AddSlot( SlotIndex )
		[
			SAssignNew(GameLayerManager, SGameLayerManager)
			.SceneViewport(this, &SLevelViewport::GetGameSceneViewport)
			[
				PIEViewportOverlayWidget.ToSharedRef()
			]
		];

		++SlotIndex;
#endif

	ViewportOverlay->AddSlot( SlotIndex )
	.HAlign(HAlign_Right)
	[
		SAssignNew( ActorPreviewHorizontalBox, SHorizontalBox )
	];

	ViewportOverlay->AddSlot(SlotIndex)
	.VAlign(VAlign_Bottom)
	.HAlign(HAlign_Left)
	.Padding(5.0f)
	[
		SNew(SLevelViewportControlsPopup)
		.Visibility(this, &SLevelViewport::GetViewportControlsVisibility)
	];

	ViewportOverlay->AddSlot( SlotIndex )
	.VAlign( VAlign_Bottom )
	.HAlign( HAlign_Right )
	.Padding( 5.0f )
	[
		SNew(SVerticalBox)
		+ SVerticalBox::Slot()
		.AutoHeight()
		.Padding(2.0f, 1.0f, 2.0f, 1.0f)
		[
			SNew(SHorizontalBox)
			.Visibility(this, &SLevelViewport::GetCurrentFeatureLevelPreviewTextVisibility)
			// Current level label
			+ SHorizontalBox::Slot()
			.AutoWidth()
			.Padding(2.0f, 1.0f, 2.0f, 1.0f)
			[
				SNew(STextBlock)
				.Text(this, &SLevelViewport::GetCurrentFeatureLevelPreviewText, true)
				.Font(FEditorStyle::GetFontStyle(TEXT("MenuItem.Font")))
				.ShadowOffset(FVector2D(1, 1))
			]

			// Current level
			+ SHorizontalBox::Slot()
				.AutoWidth()
				.Padding(4.0f, 1.0f, 2.0f, 1.0f)
				[
					SNew(STextBlock)
					.Text(this, &SLevelViewport::GetCurrentFeatureLevelPreviewText, false)
					.Font(FEditorStyle::GetFontStyle(TEXT("MenuItem.Font")))
					.ColorAndOpacity(FLinearColor(0.4f, 1.0f, 1.0f))
					.ShadowOffset(FVector2D(1, 1))
				]
		]
		+ SVerticalBox::Slot()
		.AutoHeight()
		.Padding(2.0f, 1.0f, 2.0f, 1.0f)
		[
			SNew(SHorizontalBox)
			.Visibility(this, &SLevelViewport::GetCurrentLevelTextVisibility)
			// Current level label
			+ SHorizontalBox::Slot()
			.AutoWidth()
			.Padding(2.0f, 1.0f, 2.0f, 1.0f)
			[
				SNew(STextBlock)
				.Text(this, &SLevelViewport::GetCurrentLevelText, true)
				.Font(FEditorStyle::GetFontStyle(TEXT("MenuItem.Font")))
				.ShadowOffset(FVector2D(1, 1))
			]

			// Current level
			+ SHorizontalBox::Slot()
				.AutoWidth()
				.Padding(4.0f, 1.0f, 2.0f, 1.0f)
				[
					SNew(STextBlock)
					.Text(this, &SLevelViewport::GetCurrentLevelText, false)
					.Font(FEditorStyle::GetFontStyle(TEXT("MenuItem.Font")))
					.ColorAndOpacity(FLinearColor(0.4f, 1.0f, 1.0f))
					.ShadowOffset(FVector2D(1, 1))
				]
		]
	];

	// Add highres screenshot region capture editing widget
	ViewportOverlay->AddSlot(SlotIndex)
	.VAlign( VAlign_Fill )
	.HAlign( HAlign_Fill )
	.Padding( 0 )
		[
			SAssignNew(CaptureRegionWidget, SCaptureRegionWidget)
		];
}

void SLevelViewport::ConstructLevelEditorViewportClient( const FArguments& InArgs )
{
	LevelViewportClient = MakeShareable( new FLevelEditorViewportClient(SharedThis(this)) );

	// Default level viewport client values for settings that could appear in layout config ini
	FLevelEditorViewportInstanceSettings ViewportInstanceSettings;
	ViewportInstanceSettings.ViewportType = InArgs._ViewportType;
	ViewportInstanceSettings.PerspViewModeIndex = VMI_Lit;
	ViewportInstanceSettings.OrthoViewModeIndex = VMI_BrushWireframe;
	ViewportInstanceSettings.bIsRealtime = InArgs._Realtime;

	FEngineShowFlags EditorShowFlags(ESFIM_Editor);
	FEngineShowFlags GameShowFlags(ESFIM_Game);
		
	// Use config key if it exists to set up the level viewport client
	if(!ConfigKey.IsEmpty())
	{
		const FLevelEditorViewportInstanceSettings* const ViewportInstanceSettingsPtr = GetDefault<ULevelEditorViewportSettings>()->GetViewportInstanceSettings(ConfigKey);
		ViewportInstanceSettings = (ViewportInstanceSettingsPtr) ? *ViewportInstanceSettingsPtr : LoadLegacyConfigFromIni(ConfigKey, ViewportInstanceSettings);

		if(!ViewportInstanceSettings.EditorShowFlagsString.IsEmpty())
		{
			EditorShowFlags.SetFromString(*ViewportInstanceSettings.EditorShowFlagsString);
		}

		if(!ViewportInstanceSettings.GameShowFlagsString.IsEmpty())
		{
			GameShowFlags.SetFromString(*ViewportInstanceSettings.GameShowFlagsString);
		}

		if(!GetBufferVisualizationData().GetMaterial(ViewportInstanceSettings.BufferVisualizationMode))
		{
			ViewportInstanceSettings.BufferVisualizationMode = NAME_None;
		}
	}

	if(ViewportInstanceSettings.ViewportType == LVT_Perspective)
	{
		ApplyViewMode(ViewportInstanceSettings.PerspViewModeIndex, true, EditorShowFlags);
		ApplyViewMode(ViewportInstanceSettings.PerspViewModeIndex, true, GameShowFlags);
	}
	else
	{
		ApplyViewMode(ViewportInstanceSettings.OrthoViewModeIndex, false, EditorShowFlags);
		ApplyViewMode(ViewportInstanceSettings.OrthoViewModeIndex, false, GameShowFlags);
	}

	// Disabling some features for orthographic views. 
	if(ViewportInstanceSettings.ViewportType != LVT_Perspective)
	{
		EditorShowFlags.MotionBlur = 0;
		EditorShowFlags.Fog = 0;
		EditorShowFlags.DepthOfField = 0;
		GameShowFlags.MotionBlur = 0;
		GameShowFlags.Fog = 0;
		GameShowFlags.DepthOfField = 0;
	}

	EditorShowFlags.SetSnap(1);
	GameShowFlags.SetSnap(1);

	// Create level viewport client
	LevelViewportClient->ParentLevelEditor = ParentLevelEditor.Pin();
	LevelViewportClient->ViewportType = ViewportInstanceSettings.ViewportType;
	LevelViewportClient->bSetListenerPosition = false;
	LevelViewportClient->EngineShowFlags = EditorShowFlags;
	LevelViewportClient->LastEngineShowFlags = GameShowFlags;
	LevelViewportClient->CurrentBufferVisualizationMode = ViewportInstanceSettings.BufferVisualizationMode;
	LevelViewportClient->ExposureSettings = ViewportInstanceSettings.ExposureSettings;
	if(InArgs._ViewportType == LVT_Perspective)
	{
		LevelViewportClient->SetViewLocation( EditorViewportDefs::DefaultPerspectiveViewLocation );
		LevelViewportClient->SetViewRotation( EditorViewportDefs::DefaultPerspectiveViewRotation );
		LevelViewportClient->SetAllowMatineePreview(true);
	}
	LevelViewportClient->SetRealtime(ViewportInstanceSettings.bIsRealtime);
	LevelViewportClient->SetShowStats(ViewportInstanceSettings.bShowStats);
	if (ViewportInstanceSettings.bShowFPS_DEPRECATED)
	{
		GetMutableDefault<ULevelEditorViewportSettings>()->bSaveEngineStats = true;
		ViewportInstanceSettings.EnabledStats.AddUnique(TEXT("FPS"));
	}
	if (GetDefault<ULevelEditorViewportSettings>()->bSaveEngineStats)
	{
		GEngine->SetEngineStats(GetWorld(), LevelViewportClient.Get(), ViewportInstanceSettings.EnabledStats, true);
	}
	LevelViewportClient->VisibilityDelegate.BindSP( this, &SLevelViewport::IsVisible );
	LevelViewportClient->ImmersiveDelegate.BindSP( this, &SLevelViewport::IsImmersive );
	LevelViewportClient->bDrawBaseInfo = true;
	LevelViewportClient->bDrawVertices = true;
	LevelViewportClient->ViewFOV = LevelViewportClient->FOVAngle = ViewportInstanceSettings.FOVAngle;
	
	// Set the selection outline flag based on preferences
	LevelViewportClient->EngineShowFlags.SelectionOutline = GetDefault<ULevelEditorViewportSettings>()->bUseSelectionOutline;
	
	// Always composite editor objects after post processing in the editor
	LevelViewportClient->EngineShowFlags.CompositeEditorPrimitives = true;

	LevelViewportClient->SetViewModes(ViewportInstanceSettings.PerspViewModeIndex, ViewportInstanceSettings.OrthoViewModeIndex );
}

const FSceneViewport* SLevelViewport::GetGameSceneViewport() const
{
	return ActiveViewport.Get();
}

FReply SLevelViewport::OnKeyDown( const FGeometry& MyGeometry, const FKeyEvent& InKeyEvent )
{
	FReply Reply = FReply::Unhandled();

	if( HasPlayInEditorViewport() || LevelViewportClient->IsSimulateInEditorViewport() )
	{
		// Only process commands for pie when a play world is active
		FPlayWorldCommands::GlobalPlayWorldActions->ProcessCommandBindings( InKeyEvent );

		// Always handle commands in pie so they arent bubbled to editor only widgets
		Reply = FReply::Handled();
	}
	
	if( !IsPlayInEditorViewportActive() )
	{
		Reply = SEditorViewport::OnKeyDown(MyGeometry,InKeyEvent);


		// If we are in immersive mode and the event was not handled, we will check to see if the the 
		//  optional parent level editor is set.  If it is, we give it a chance to handle the key event.
		//  This command forwarding is currently only needed when in immersive mode because in that case 
		//  the SLevelEditor is not a direct parent of the viewport.  
		if ( this->IsImmersive() && !Reply.IsEventHandled() )
		{
			TSharedPtr<SLevelEditor> ParentLevelEditorSharedPtr = ParentLevelEditor.Pin();
			if( ParentLevelEditorSharedPtr.IsValid() )
			{
				Reply = ParentLevelEditorSharedPtr->OnKeyDownInViewport( MyGeometry, InKeyEvent );
			}
		}
	}
	return Reply;
}

void SLevelViewport::OnDragEnter( const FGeometry& MyGeometry, const FDragDropEvent& DragDropEvent )
{
	// Prevent OnDragEnter from reentering because it will affect the drop preview placement and management.
	// This may happen currently if an unloaded class is dragged from the class viewer and a slow task is triggered,
	// which re-ticks slate and triggers another mouse move.
	static bool bDragEnterReentranceGuard = false;
	if ( !bDragEnterReentranceGuard )
	{
		bDragEnterReentranceGuard = true;
		// Don't execute the dragdrop op if the current level is locked.
		// This prevents duplicate warning messages firing on DragEnter and Placement.
		ULevel* CurrentLevel = (GetWorld()) ? GetWorld()->GetCurrentLevel() : NULL;

		if ( CurrentLevel && !FLevelUtils::IsLevelLocked(CurrentLevel) )
		{
			if ( HandleDragObjects(MyGeometry, DragDropEvent) )
			{
				if ( HandlePlaceDraggedObjects(MyGeometry, DragDropEvent, /*bCreateDropPreview=*/true) )
				{
					DragDropEvent.GetOperation()->SetDecoratorVisibility(false);
				}
			}
		}
		
		bDragEnterReentranceGuard = false;
	}
}

void SLevelViewport::OnDragLeave( const FDragDropEvent& DragDropEvent )
{
	if ( LevelViewportClient->HasDropPreviewActors() )
	{
		LevelViewportClient->DestroyDropPreviewActors();
	}

	if (DragDropEvent.GetOperation().IsValid())
	{
		DragDropEvent.GetOperation()->SetDecoratorVisibility(true);
	}
}

bool SLevelViewport::HandleDragObjects(const FGeometry& MyGeometry, const FDragDropEvent& DragDropEvent)
{
	bool bValidDrag = false;
	TArray<FAssetData> SelectedAssetDatas;

	TSharedPtr< FDragDropOperation > Operation = DragDropEvent.GetOperation();
	if (!Operation.IsValid())
	{
		return false;
	}

	if (Operation->IsOfType<FClassDragDropOp>())
	{
		auto ClassOperation = StaticCastSharedPtr<FClassDragDropOp>( Operation );

		bValidDrag = true;

		for (int32 DroppedAssetIdx = 0; DroppedAssetIdx < ClassOperation->ClassesToDrop.Num(); ++DroppedAssetIdx)
		{
			new(SelectedAssetDatas)FAssetData(ClassOperation->ClassesToDrop[DroppedAssetIdx].Get());
		}
	}
	else if (Operation->IsOfType<FUnloadedClassDragDropOp>())
	{
		bValidDrag = true;
	}
	else if (Operation->IsOfType<FExportTextDragDropOp>())
	{
		bValidDrag = true;
	}
	else if (Operation->IsOfType<FBrushBuilderDragDropOp>())
	{
		bValidDrag = true;

		auto BrushOperation = StaticCastSharedPtr<FBrushBuilderDragDropOp>( Operation );

		new(SelectedAssetDatas) FAssetData(BrushOperation->GetBrushBuilder().Get());
	}
	else
	{
		SelectedAssetDatas = AssetUtil::ExtractAssetDataFromDrag( DragDropEvent );

		if ( SelectedAssetDatas.Num() > 0 )
		{
			bValidDrag = true;
		}
	}

	// Update cached mouse position
	if ( bValidDrag )
	{
		// Grab viewport to offset click position correctly
		FIntPoint ViewportOrigin, ViewportSize;
		LevelViewportClient->GetViewportDimensions(ViewportOrigin, ViewportSize);

		// Save off the local mouse position from the drop point for potential use later (with Drag Drop context menu)
		CachedOnDropLocalMousePos = MyGeometry.AbsoluteToLocal( DragDropEvent.GetScreenSpacePosition() );
		CachedOnDropLocalMousePos.X -= ViewportOrigin.X;
		CachedOnDropLocalMousePos.Y -= ViewportOrigin.Y;
	}

	// Update the currently dragged actor if it exists
	bool bDroppedObjectsVisible = true;
	if (LevelViewportClient->UpdateDropPreviewActors(CachedOnDropLocalMousePos.X, CachedOnDropLocalMousePos.Y, DroppedObjects, bDroppedObjectsVisible))
	{
		// if dragged actors were hidden, show decorator
		Operation->SetDecoratorVisibility(! bDroppedObjectsVisible);
	}

	Operation->SetCursorOverride(TOptional<EMouseCursor::Type>());

	FText HintText;

	// Determine if we can drop the assets
	for ( auto InfoIt = SelectedAssetDatas.CreateConstIterator(); InfoIt; ++InfoIt )
	{
		const FAssetData& AssetData = *InfoIt;

		// Ignore invalid assets
		if ( !AssetData.IsValid() )
		{
			continue;
		}
		
		FDropQuery DropResult = LevelViewportClient->CanDropObjectsAtCoordinates(CachedOnDropLocalMousePos.X, CachedOnDropLocalMousePos.Y, AssetData);
		
		if ( !DropResult.bCanDrop )
		{
			// At least one of the assets can't be dropped.
			Operation->SetCursorOverride(EMouseCursor::SlashedCircle);
			return false;
		}
		else
		{
			if ( HintText.IsEmpty() )
			{
				HintText = DropResult.HintText;
			}
		}
	}

	if ( Operation->IsOfType<FAssetDragDropOp>() )
	{
		auto AssetOperation = StaticCastSharedPtr<FAssetDragDropOp>(DragDropEvent.GetOperation());
		AssetOperation->SetToolTip(HintText, NULL);
	}

	return bValidDrag;
}

FReply SLevelViewport::OnDragOver( const FGeometry& MyGeometry, const FDragDropEvent& DragDropEvent )
{
	if ( HandleDragObjects(MyGeometry, DragDropEvent) )
	{
		return FReply::Handled();
	}

	return FReply::Unhandled();
}

bool SLevelViewport::HandlePlaceDraggedObjects(const FGeometry& MyGeometry, const FDragDropEvent& DragDropEvent, bool bCreateDropPreview)
{
	bool bAllAssetWereLoaded = false;
	bool bValidDrop = false;
	UActorFactory* ActorFactory = NULL;

	TSharedPtr< FDragDropOperation > Operation = DragDropEvent.GetOperation();
	if (!Operation.IsValid())
	{
		return false;
	}

	// Don't handle the placement if we couldn't handle the drag
	if (!HandleDragObjects(MyGeometry, DragDropEvent))
	{
		return false;
	}

	if (Operation->IsOfType<FClassDragDropOp>())
	{
		auto ClassOperation = StaticCastSharedPtr<FClassDragDropOp>( Operation );

		DroppedObjects.Empty();

		// Check if the asset is loaded, used to see if the context menu should be available
		bAllAssetWereLoaded = true;

		for (int32 DroppedAssetIdx = 0; DroppedAssetIdx < ClassOperation->ClassesToDrop.Num(); ++DroppedAssetIdx)
		{
			UObject* Object = ClassOperation->ClassesToDrop[DroppedAssetIdx].Get();

			if(Object)
			{
				DroppedObjects.Add(Object);
			}
			else
			{	
				bAllAssetWereLoaded = false;
			}
		}

		bValidDrop = true;
	}
	else if (Operation->IsOfType<FUnloadedClassDragDropOp>())
	{
		TSharedPtr<FUnloadedClassDragDropOp> DragDropOp = StaticCastSharedPtr<FUnloadedClassDragDropOp>( Operation );

		DroppedObjects.Empty();

		// Check if the asset is loaded, used to see if the context menu should be available
		bAllAssetWereLoaded = true;

		TArray< FClassPackageData >& AssetArray = *(DragDropOp->AssetsToDrop.Get());
		for (int32 DroppedAssetIdx = 0; DroppedAssetIdx < AssetArray.Num(); ++DroppedAssetIdx)
		{
			bValidDrop = true;

			FString& AssetName = AssetArray[DroppedAssetIdx].AssetName;

			// Check to see if the asset can be found, otherwise load it.
			UObject* Object = FindObject<UObject>(NULL, *AssetName);
			if(Object == NULL)
			{
				// Check to see if the dropped asset was a blueprint
				const FString& PackageName = AssetArray[DroppedAssetIdx].GeneratedPackageName;
				Object = FindObject<UObject>(NULL, *FString::Printf(TEXT("%s.%s"), *PackageName, *AssetName));

				if ( Object == NULL )
				{
					// Load the package.
					GWarn->BeginSlowTask( LOCTEXT("OnDrop_FullyLoadPackage", "Fully Loading Package For Drop"), true, false );
					UPackage* Package = LoadPackage(NULL, *PackageName, LOAD_NoRedirects );
					if (Package)
					{
						Package->FullyLoad();
					}
					GWarn->EndSlowTask();

					Object = FindObject<UObject>(Package, *AssetName);
				}
			}

			// Check again if it has been loaded, if not, mark that all were not loaded and move on.
			if(Object)
			{
				DroppedObjects.Add(Object);
			}
			else
			{	
				bAllAssetWereLoaded = false;
			}
		}
	}
	else if (Operation->IsOfType<FAssetDragDropOp>())
	{
		bValidDrop = true;
		DroppedObjects.Empty();

		TSharedPtr<FAssetDragDropOp> DragDropOp = StaticCastSharedPtr<FAssetDragDropOp>( Operation );

		ActorFactory = DragDropOp->ActorFactory.Get();

		bAllAssetWereLoaded = true;
		for (int32 AssetIdx = 0; AssetIdx < DragDropOp->AssetData.Num(); ++AssetIdx)
		{
			const FAssetData& AssetData = DragDropOp->AssetData[AssetIdx];

			UObject* Asset = AssetData.GetAsset();
			if ( Asset != NULL )
			{
				DroppedObjects.Add( Asset );
			}
			else
			{
				bAllAssetWereLoaded = false;
			}
		}
	}
	// OLE drops are blocking which causes problem when positioning and maintaining the drop preview
	// Drop preview is disabled when dragging from external sources
	else if ( !bCreateDropPreview && Operation->IsOfType<FExternalDragOperation>() )
	{
		bValidDrop = true;
		DroppedObjects.Empty();

		TArray<FAssetData> DroppedAssetDatas = AssetUtil::ExtractAssetDataFromDrag(DragDropEvent);

		bAllAssetWereLoaded = true;
		for (int32 AssetIdx = 0; AssetIdx < DroppedAssetDatas.Num(); ++AssetIdx)
		{
			const FAssetData& AssetData = DroppedAssetDatas[AssetIdx];

			UObject* Asset = AssetData.GetAsset();
			if ( Asset != NULL )
			{
				DroppedObjects.Add( Asset );
			}
			else
			{
				bAllAssetWereLoaded = false;
			}
		}
	}
	else if ( Operation->IsOfType<FExportTextDragDropOp>() )
	{
		bValidDrop = true;

		TSharedPtr<FExportTextDragDropOp> DragDropOp = StaticCastSharedPtr<FExportTextDragDropOp>( Operation );

		// Check if the asset is loaded, used to see if the context menu should be available
		bAllAssetWereLoaded = true;
		DroppedObjects.Empty();

		// Create a container object to hold the export text and pass it into the actor placement code
		UExportTextContainer* NewContainer = NewObject<UExportTextContainer>();
		NewContainer->ExportText = DragDropOp->ActorExportText;
		DroppedObjects.Add(NewContainer);
	}
	else if ( Operation->IsOfType<FBrushBuilderDragDropOp>() )
	{
		bValidDrop = true;
		DroppedObjects.Empty();

		TSharedPtr<FBrushBuilderDragDropOp> DragDropOp = StaticCastSharedPtr<FBrushBuilderDragDropOp>( Operation );

		if(DragDropOp->GetBrushBuilder().IsValid())
		{
			DroppedObjects.Add(DragDropOp->GetBrushBuilder().Get());
		}
	}

	if ( bValidDrop )
	{
		// Grab the hit proxy, used for the (potential) context menu
		HHitProxy* HitProxy = LevelViewportClient->Viewport->GetHitProxy(CachedOnDropLocalMousePos.X, CachedOnDropLocalMousePos.Y);

		// If Ctrl is down, pop in the context menu
		const bool bShowDropContextMenu = !bCreateDropPreview && DragDropEvent.IsControlDown() && ( !HitProxy || !( HitProxy->IsA( HWidgetAxis::StaticGetType() ) ) );
		bool bDropSuccessful = false;

		// Make sure the drop preview is destroyed
		LevelViewportClient->DestroyDropPreviewActors();

		if( !bShowDropContextMenu || !bCreateDropPreview )
		{
			// Otherwise just attempt to drop the object(s)
			TArray< AActor* > TemporaryActors;
			// Only select actor on drop
			const bool SelectActor = !bCreateDropPreview;
			bDropSuccessful = LevelViewportClient->DropObjectsAtCoordinates(CachedOnDropLocalMousePos.X, CachedOnDropLocalMousePos.Y, DroppedObjects, TemporaryActors, false, bCreateDropPreview, SelectActor, ActorFactory);
		}
		else if ( bAllAssetWereLoaded && DroppedObjects.Num() > 0 )
		{
			TWeakPtr< SWindow > ContextMenuWindow = FSlateApplication::Get().PushMenu( SharedThis( this ),
				BuildViewportDragDropContextMenu(), DragDropEvent.GetScreenSpacePosition(), FPopupTransitionEffect( FPopupTransitionEffect::ContextMenu ) );
			bDropSuccessful = true;
		}

		// Give the editor focus (quick Undo/Redo support after a drag drop operation)
		if(ParentLevelEditor.IsValid())
		{
			FGlobalTabmanager::Get()->DrawAttentionToTabManager(ParentLevelEditor.Pin()->GetTabManager());
		}

		if(bDropSuccessful)
		{
			SetKeyboardFocusToThisViewport();
		}

		return bDropSuccessful;
	}
	
	return false;
}

FReply SLevelViewport::OnDrop( const FGeometry& MyGeometry, const FDragDropEvent& DragDropEvent )
{
	ULevel* CurrentLevel = (GetWorld()) ? GetWorld()->GetCurrentLevel() : NULL;

	if (CurrentLevel && !FLevelUtils::IsLevelLocked(CurrentLevel))
	{
		return HandlePlaceDraggedObjects(MyGeometry, DragDropEvent, /*bCreateDropPreview=*/false) ? FReply::Handled() : FReply::Unhandled();
	}
	else
	{
		FNotificationInfo Info(LOCTEXT("Error_OperationDisallowedOnLockedLevel", "The requested operation could not be completed because the level is locked."));
		Info.ExpireDuration = 3.0f;
		FSlateNotificationManager::Get().AddNotification(Info);
		return FReply::Handled();
	}
}


void SLevelViewport::Tick( const FGeometry& AllottedGeometry, const double InCurrentTime, const float InDeltaTime )
{
	SEditorViewport::Tick( AllottedGeometry, InCurrentTime, InDeltaTime );

	const bool bContainsFocus = HasFocusedDescendants();

	// When we have focus we update the 'Allow Throttling' option in slate to be disabled so that interactions in the
	// viewport with Slate widgets that are part of the game, don't throttle.
	if ( GEditor->PlayWorld != nullptr && bPIEContainsFocus != bContainsFocus )
	{
		// We can arrive at this point before creating throttling manager (which registers the cvar), so create it explicitly.
		static const FSlateThrottleManager & ThrottleManager = FSlateThrottleManager::Get();
		static IConsoleVariable* AllowThrottling = IConsoleManager::Get().FindConsoleVariable(TEXT("Slate.bAllowThrottling"));
		check(AllowThrottling);

		if ( bContainsFocus )
		{
			UserAllowThrottlingValue = AllowThrottling->GetInt();
			AllowThrottling->Set(0);
		}
		else
		{
			AllowThrottling->Set(UserAllowThrottlingValue);
		}

		bPIEContainsFocus = bContainsFocus;
	}

	// We defer starting animation playback because very often there may be a large hitch after the frame in which
	// the animation was triggered, and we don't want to start animating until after that hitch.  Otherwise, the
	// user could miss part of the animation, or even the whole thing!
	if( bViewTransitionAnimPending )
	{
		ViewTransitionAnim.Play(this->AsShared());
		bViewTransitionAnimPending = false;
	}

	// If we've completed a transition, then start animating back to our regular border.  We
	// do this so that we can avoid a popping artifact after PIE/SIE ends.
	if( !ViewTransitionAnim.IsPlaying() && ViewTransitionType != EViewTransition::None )
	{
		if(ViewTransitionType == EViewTransition::StartingPlayInEditor)
		{
			if(PIEOverlaySlotIndex)
			{
				PIEOverlayAnim = FCurveSequence(0.0f, SLevelViewportPIEAnimation::MouseControlLabelFadeout, ECurveEaseFunction::CubicInOut);
				PIEOverlayAnim.Play(this->AsShared());
			}
		}
		ViewTransitionType = EViewTransition::None;
		ViewTransitionAnim = FCurveSequence( 0.0f, 0.25f, ECurveEaseFunction::QuadOut );
		ViewTransitionAnim.PlayReverse(this->AsShared());
	}

	if(IsPlayInEditorViewportActive() && bPIEHasFocus != ActiveViewport->HasMouseCapture())
	{
		bPIEHasFocus = ActiveViewport->HasMouseCapture();
		PIEOverlayAnim = FCurveSequence(0.0f, SLevelViewportPIEAnimation::MouseControlLabelFadeout, ECurveEaseFunction::CubicInOut);
		PIEOverlayAnim.Play(this->AsShared());
	}

	// Update actor preview viewports, if we have any
	UpdateActorPreviewViewports();

#if STATS
	// Check to see if there are any new stat group which need registering with the viewports
	extern CORE_API void CheckForRegisteredStatGroups();
	CheckForRegisteredStatGroups();
#endif
}


TSharedRef< SWidget > SLevelViewport::BuildViewportDragDropContextMenu()
{
	// Get all menu extenders for this context menu from the level editor module
	FLevelEditorModule& LevelEditorModule = FModuleManager::GetModuleChecked<FLevelEditorModule>( LevelEditorName );
	TArray<FLevelEditorModule::FLevelViewportMenuExtender_SelectedObjects> MenuExtenderDelegates = LevelEditorModule.GetAllLevelViewportDragDropContextMenuExtenders();

	TArray<TSharedPtr<FExtender>> Extenders;
	for (int32 i = 0; i < MenuExtenderDelegates.Num(); ++i)
	{
		if (MenuExtenderDelegates[i].IsBound())
		{
			Extenders.Add(MenuExtenderDelegates[i].Execute(CommandList.ToSharedRef(), DroppedObjects));
		}
	}
	TSharedPtr<FExtender> MenuExtender = FExtender::Combine(Extenders);

	// Builds a context menu used to perform specific actions on actors selected within the editor
	const bool bShouldCloseWindowAfterMenuSelection = true;
	FMenuBuilder ViewportContextMenuBuilder( bShouldCloseWindowAfterMenuSelection, CommandList, MenuExtender );
	{
		FLevelViewportDropContextMenuImpl::FillDropAddReplaceActorMenu( false, ViewportContextMenuBuilder );

		// If any actors are in the current editor selection, add submenu for swapping out those actors with an asset from the chosen factory
		if( GEditor->GetSelectedActorCount() > 0 && !AssetSelectionUtils::IsBuilderBrushSelected() )
		{
			FLevelViewportDropContextMenuImpl::FillDropAddReplaceActorMenu( true, ViewportContextMenuBuilder );
		}

		if(DroppedObjects.Num() > 0)
		{
			// Grab the hit proxy, used for determining which object we're potentially targeting
			const HHitProxy* DroppedUponProxy = LevelViewportClient->Viewport->GetHitProxy(CachedOnDropLocalMousePos.X, CachedOnDropLocalMousePos.Y);
			UObject* FirstDroppedObject = DroppedObjects[0];

			// If we're using a material asset, check if the apply material option(s) should be added
			if(DroppedUponProxy && Cast<UMaterialInterface>(FirstDroppedObject) && LevelViewportClient->CanApplyMaterialToHitProxy(DroppedUponProxy))
			{
				ViewportContextMenuBuilder.BeginSection("ApplyMaterial");
				{
					ViewportContextMenuBuilder.AddMenuEntry( FLevelViewportCommands::Get().ApplyMaterialToActor );
				}
				ViewportContextMenuBuilder.EndSection();
			}
		}
	}

	return ViewportContextMenuBuilder.MakeWidget();
}

void SLevelViewport::OnMapChanged( UWorld* World, EMapChangeType::Type MapChangeType )
{
	if( World && ( ( World == GetWorld() ) || ( World->EditorViews[LevelViewportClient->ViewportType].CamUpdated ) ) )
	{
		if( MapChangeType == EMapChangeType::LoadMap )
		{
			if (World->EditorViews[LevelViewportClient->ViewportType].CamOrthoZoom == 0.0f)
			{
				World->EditorViews[LevelViewportClient->ViewportType].CamOrthoZoom = DEFAULT_ORTHOZOOM;
			}
	
			ResetNewLevelViewFlags();

			bool bInitializedOrthoViewport = false;
			for (int32 ViewportType = 0; ViewportType < LVT_MAX; ViewportType++)
			{
				if (ViewportType == LVT_Perspective || !bInitializedOrthoViewport)
				{
					LevelViewportClient->SetInitialViewTransform(
						static_cast<ELevelViewportType>(ViewportType),
						World->EditorViews[ViewportType].CamPosition,
						World->EditorViews[ViewportType].CamRotation,
						World->EditorViews[ViewportType].CamOrthoZoom);

					if (ViewportType != LVT_Perspective)
					{
						bInitializedOrthoViewport = true;
					}
				}
			}
		}
		else if( MapChangeType == EMapChangeType::SaveMap )
		{
			//@todo there could potentially be more than one of the same viewport type.  This effectively takes the last one of a specific type
			World->EditorViews[LevelViewportClient->ViewportType] = 
				FLevelViewportInfo( 
					LevelViewportClient->GetViewLocation(),
					LevelViewportClient->GetViewRotation(), 
					LevelViewportClient->GetOrthoZoom() );
		}
		else if( MapChangeType == EMapChangeType::NewMap )
		{
		
			ResetNewLevelViewFlags();

			LevelViewportClient->ResetViewForNewMap();
		}
		World->EditorViews[LevelViewportClient->ViewportType].CamUpdated = false;

		RedrawViewport(true);
	}
}

void SLevelViewport::OnLevelActorsRemoved(AActor* InActor)
{
	// Kill any existing actor previews that have expired
	for( int32 PreviewIndex = 0; PreviewIndex < ActorPreviews.Num(); ++PreviewIndex )
	{
		AActor* ExistingActor = ActorPreviews[PreviewIndex].Actor.Get();
		if ( !ExistingActor || ExistingActor == InActor )
		{
			// decrement index so we don't miss next preview after deleting
			RemoveActorPreview( PreviewIndex-- );
		}
	}
}

void FLevelViewportDropContextMenuImpl::FillDropAddReplaceActorMenu( bool bReplace, FMenuBuilder& MenuBuilder )
{
	// Builds a submenu for the Drag Drop context menu used to replace all actors in the current editor selection with a different asset
	TArray<FAssetData> SelectedAssets;
	AssetSelectionUtils::GetSelectedAssets( SelectedAssets );

	FAssetData TargetAssetData;
	if ( SelectedAssets.Num() > 0 )
	{
		TargetAssetData = SelectedAssets.Top();
	}

	TArray< FActorFactoryAssetProxy::FMenuItem > SelectedAssetMenuOptions;
	FActorFactoryAssetProxy::GenerateActorFactoryMenuItems( TargetAssetData, &SelectedAssetMenuOptions, false );

	if(SelectedAssetMenuOptions.Num() > 0)
	{
		FText AddReplaceTitle = (bReplace)? FText::GetEmpty() : LOCTEXT("DragDropContext_AddAsType", "Add As Type");

		MenuBuilder.BeginSection("AddReplace", AddReplaceTitle);
		{
			for( int32 ItemIndex = 0; ItemIndex < SelectedAssetMenuOptions.Num(); ++ItemIndex )
			{
				const FActorFactoryAssetProxy::FMenuItem& MenuItem = SelectedAssetMenuOptions[ItemIndex];
	
				if ( bReplace )
				{
					FUIAction Action( FExecuteAction::CreateStatic( &FLevelEditorActionCallbacks::ReplaceActors_Clicked, MenuItem.FactoryToUse, MenuItem.AssetData ) );
	
					FText MenuEntryName = FText::Format( NSLOCTEXT("LevelEditor", "ReplaceActorMenuFormat", "Replace with {0}"), MenuItem.FactoryToUse->GetDisplayName() );
					if ( MenuItem.AssetData.IsValid() )
					{
						MenuEntryName = FText::Format( NSLOCTEXT("LevelEditor", "ReplaceActorUsingAssetMenuFormat", "Replace with {0}: {1}"), 
							MenuItem.FactoryToUse->GetDisplayName(), 
							FText::FromName( MenuItem.AssetData.AssetName ) );
					}
				}
				else
				{
					FUIAction Action( FExecuteAction::CreateStatic( &FLevelEditorActionCallbacks::AddActor_Clicked, MenuItem.FactoryToUse, MenuItem.AssetData, false ) );
				
					FText MenuEntryName = FText::Format( NSLOCTEXT("SLevelViewport", "AddActorMenuFormat", "Add {0}"), MenuItem.FactoryToUse->GetDisplayName() );
					if ( MenuItem.AssetData.IsValid() )
					{
						MenuEntryName = FText::Format( NSLOCTEXT("SLevelViewport", "AddActorUsingAssetMenuFormat", "Add {0}: {1}"), 
							MenuItem.FactoryToUse->GetDisplayName(), 
							FText::FromName( MenuItem.AssetData.AssetName ) );
					}
				}
			}
		}
		MenuBuilder.EndSection();
	}
}

/**
 * Bound event Triggered via FLevelViewportCommands::ApplyMaterialToActor, attempts to apply a material selected in the content browser
 * to an actor being hovered over in the Editor viewport.
 */ 
void SLevelViewport::OnApplyMaterialToViewportTarget()
{
	if(DroppedObjects.Num() > 0)
	{
		// Grab the hit proxy, used for determining which object we're potentially targeting
		const HHitProxy* DroppedUponProxy = LevelViewportClient->Viewport->GetHitProxy(CachedOnDropLocalMousePos.X, CachedOnDropLocalMousePos.Y);
		UObject* FirstDroppedObject = DroppedObjects[0];

		// Ensure we're dropping a material asset and our target is an acceptable receiver
		if(DroppedUponProxy && Cast<UMaterialInterface>(FirstDroppedObject) && LevelViewportClient->CanApplyMaterialToHitProxy(DroppedUponProxy))
		{
			// Drop the object, but ensure we're only affecting the target actor, not whatever may be in the current selection
			TArray< AActor* > TemporaryActors;
			LevelViewportClient->DropObjectsAtCoordinates(CachedOnDropLocalMousePos.X,CachedOnDropLocalMousePos.Y, DroppedObjects, TemporaryActors, true);
		}
	}
}

void SLevelViewport::BindCommands()
{
	SEditorViewport::BindCommands();

	FUICommandList& UICommandListRef = *CommandList;

	BindOptionCommands( UICommandListRef );
	BindViewCommands( UICommandListRef );
	BindShowCommands( UICommandListRef );
	BindDropCommands( UICommandListRef );

	if ( ParentLevelEditor.IsValid() )
	{
		UICommandListRef.Append(ParentLevelEditor.Pin()->GetLevelEditorActions().ToSharedRef());
	}

	UICommandListRef.SetCanProduceActionForCommand( FUICommandList::FCanProduceActionForCommand::CreateSP(this, &SLevelViewport::CanProduceActionForCommand) );
}
	
void SLevelViewport::BindOptionCommands( FUICommandList& CommandList )
{
	const FLevelViewportCommands& ViewportActions = FLevelViewportCommands::Get();

	CommandList.MapAction( 
		ViewportActions.AdvancedSettings,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnAdvancedSettings ) );

	CommandList.MapAction( 
		ViewportActions.ToggleMaximize,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnToggleMaximizeMode ),
		FCanExecuteAction::CreateSP( this, &SLevelViewport::CanToggleMaximizeMode ) );

	
	CommandList.MapAction(
		ViewportActions.ToggleGameView,
		FExecuteAction::CreateSP( this, &SLevelViewport::ToggleGameView ),
		FCanExecuteAction::CreateSP( this, &SLevelViewport::CanToggleGameView ),
		FIsActionChecked::CreateSP( this, &SLevelViewport::IsInGameView ) );

	CommandList.MapAction(
		ViewportActions.ToggleImmersive,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnToggleImmersive),
		FCanExecuteAction(),
		FIsActionChecked::CreateSP( this, &SLevelViewport::IsImmersive ) );


	CommandList.MapAction(
		ViewportActions.AllowMatineePreview,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnToggleAllowMatineePreview ),
		FCanExecuteAction(),
		FIsActionChecked::CreateSP( this, &SLevelViewport::DoesAllowMatineePreview )
		);


	CommandList.MapAction(
		ViewportActions.CreateCamera,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnCreateCameraActor ),
		FCanExecuteAction(),
		FCanExecuteAction::CreateSP( this, &SLevelViewport::IsPerspectiveViewport ) 
		);

	CommandList.MapAction(
		ViewportActions.HighResScreenshot,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnTakeHighResScreenshot ),
		FCanExecuteAction()
		);

	CommandList.MapAction(
		ViewportActions.ToggleActorPilotCameraView,
		FExecuteAction::CreateSP(this, &SLevelViewport::ToggleActorPilotCameraView),
		FCanExecuteAction(),
		FIsActionChecked::CreateSP( this, &SLevelViewport::IsLockedCameraViewEnabled )
		);

	// Map each bookmark action
	for( int32 BookmarkIndex = 0; BookmarkIndex < AWorldSettings::MAX_BOOKMARK_NUMBER; ++BookmarkIndex )
	{
		CommandList.MapAction( 
			ViewportActions.JumpToBookmarkCommands[BookmarkIndex],
			FExecuteAction::CreateSP( this, &SLevelViewport::OnJumpToBookmark, BookmarkIndex )
			);

		CommandList.MapAction( 
			ViewportActions.SetBookmarkCommands[BookmarkIndex],
			FExecuteAction::CreateSP( this, &SLevelViewport::OnSetBookmark, BookmarkIndex )
			);

		CommandList.MapAction( 
			ViewportActions.ClearBookmarkCommands[BookmarkIndex],
			FExecuteAction::CreateSP( this, &SLevelViewport::OnClearBookMark, BookmarkIndex )
			);
	}

	CommandList.MapAction(
		ViewportActions.ClearAllBookMarks,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnClearAllBookMarks )		
		);
}

void SLevelViewport::BindViewCommands( FUICommandList& CommandList )
{
	const FLevelViewportCommands& ViewportActions = FLevelViewportCommands::Get();

	CommandList.MapAction(
		ViewportActions.FindInLevelScriptBlueprint,
		FExecuteAction::CreateSP( this, &SLevelViewport::FindSelectedInLevelScript ),
		FCanExecuteAction::CreateSP( this, &SLevelViewport::CanFindSelectedInLevelScript ) 
		);

	CommandList.MapAction(
		ViewportActions.EjectActorPilot,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnActorUnlock ),
		FCanExecuteAction::CreateSP( this, &SLevelViewport::CanExecuteActorUnlock )
		);

	CommandList.MapAction(
		ViewportActions.PilotSelectedActor,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnActorLockSelected ),
		FCanExecuteAction::CreateSP( this, &SLevelViewport::CanExecuteActorLockSelected )
		);

	CommandList.MapAction(
		ViewportActions.ViewportConfig_OnePane,
		FExecuteAction::CreateSP(this, &SLevelViewport::OnSetViewportConfiguration, LevelViewportConfigurationNames::OnePane),
		FCanExecuteAction(),
		FIsActionChecked::CreateSP(this, &SLevelViewport::IsViewportConfigurationSet, LevelViewportConfigurationNames::OnePane));

	CommandList.MapAction(
		ViewportActions.ViewportConfig_TwoPanesH,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnSetViewportConfiguration, LevelViewportConfigurationNames::TwoPanesHoriz ),
		FCanExecuteAction(),
		FIsActionChecked::CreateSP( this, &SLevelViewport::IsViewportConfigurationSet, LevelViewportConfigurationNames::TwoPanesHoriz ));

	CommandList.MapAction(
		ViewportActions.ViewportConfig_TwoPanesV,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnSetViewportConfiguration, LevelViewportConfigurationNames::TwoPanesVert ),
		FCanExecuteAction(),
		FIsActionChecked::CreateSP( this, &SLevelViewport::IsViewportConfigurationSet, LevelViewportConfigurationNames::TwoPanesVert ));

	CommandList.MapAction(
		ViewportActions.ViewportConfig_ThreePanesLeft,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnSetViewportConfiguration, LevelViewportConfigurationNames::ThreePanesLeft ),
		FCanExecuteAction(),
		FIsActionChecked::CreateSP( this, &SLevelViewport::IsViewportConfigurationSet, LevelViewportConfigurationNames::ThreePanesLeft ));

	CommandList.MapAction(
		ViewportActions.ViewportConfig_ThreePanesRight,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnSetViewportConfiguration, LevelViewportConfigurationNames::ThreePanesRight ),
		FCanExecuteAction(),
		FIsActionChecked::CreateSP( this, &SLevelViewport::IsViewportConfigurationSet, LevelViewportConfigurationNames::ThreePanesRight ));

	CommandList.MapAction(
		ViewportActions.ViewportConfig_ThreePanesTop,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnSetViewportConfiguration, LevelViewportConfigurationNames::ThreePanesTop ),
		FCanExecuteAction(),
		FIsActionChecked::CreateSP( this, &SLevelViewport::IsViewportConfigurationSet, LevelViewportConfigurationNames::ThreePanesTop ));

	CommandList.MapAction(
		ViewportActions.ViewportConfig_ThreePanesBottom,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnSetViewportConfiguration, LevelViewportConfigurationNames::ThreePanesBottom ),
		FCanExecuteAction(),
		FIsActionChecked::CreateSP( this, &SLevelViewport::IsViewportConfigurationSet, LevelViewportConfigurationNames::ThreePanesBottom ));

	CommandList.MapAction(
		ViewportActions.ViewportConfig_FourPanesLeft,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnSetViewportConfiguration, LevelViewportConfigurationNames::FourPanesLeft ),
		FCanExecuteAction(),
		FIsActionChecked::CreateSP( this, &SLevelViewport::IsViewportConfigurationSet, LevelViewportConfigurationNames::FourPanesLeft ));

	CommandList.MapAction(
		ViewportActions.ViewportConfig_FourPanesRight,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnSetViewportConfiguration, LevelViewportConfigurationNames::FourPanesRight ),
		FCanExecuteAction(),
		FIsActionChecked::CreateSP( this, &SLevelViewport::IsViewportConfigurationSet, LevelViewportConfigurationNames::FourPanesRight ));

	CommandList.MapAction(
		ViewportActions.ViewportConfig_FourPanesTop,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnSetViewportConfiguration, LevelViewportConfigurationNames::FourPanesTop ),
		FCanExecuteAction(),
		FIsActionChecked::CreateSP( this, &SLevelViewport::IsViewportConfigurationSet, LevelViewportConfigurationNames::FourPanesTop ));

	CommandList.MapAction(
		ViewportActions.ViewportConfig_FourPanesBottom,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnSetViewportConfiguration, LevelViewportConfigurationNames::FourPanesBottom ),
		FCanExecuteAction(),
		FIsActionChecked::CreateSP( this, &SLevelViewport::IsViewportConfigurationSet, LevelViewportConfigurationNames::FourPanesBottom ));

	CommandList.MapAction(
		ViewportActions.ViewportConfig_FourPanes2x2,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnSetViewportConfiguration, LevelViewportConfigurationNames::FourPanes2x2 ),
		FCanExecuteAction(),
		FIsActionChecked::CreateSP( this, &SLevelViewport::IsViewportConfigurationSet, LevelViewportConfigurationNames::FourPanes2x2 ));


	// Map Buffer visualization mode actions
	for (FLevelViewportCommands::TBufferVisualizationModeCommandMap::TConstIterator It = ViewportActions.BufferVisualizationModeCommands.CreateConstIterator(); It; ++It)
	{
		const FLevelViewportCommands::FBufferVisualizationRecord& Record = It.Value();
		CommandList.MapAction(
			Record.Command,
			FExecuteAction::CreateSP( this, &SLevelViewport::ChangeBufferVisualizationMode, Record.Name ),
			FCanExecuteAction(),
			FIsActionChecked::CreateSP( this, &SLevelViewport::IsBufferVisualizationModeSelected, Record.Name ) );
	}
}


void SLevelViewport::BindShowCommands( FUICommandList& CommandList )
{
	CommandList.MapAction( 
		FLevelViewportCommands::Get().UseDefaultShowFlags,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnUseDefaultShowFlags, false ) );

	const TArray<FShowFlagData>& ShowFlagData = GetShowFlagMenuItems();

	// Bind each show flag to the same delegate.  We use the delegate payload system to figure out what show flag we are dealing with
	for( int32 ShowFlag = 0; ShowFlag < ShowFlagData.Num(); ++ShowFlag )
	{
		const FShowFlagData& SFData = ShowFlagData[ShowFlag];

		// NOTE: There should be one command per show flag so using ShowFlag as the index to ShowFlagCommands is acceptable
		CommandList.MapAction(
			FLevelViewportCommands::Get().ShowFlagCommands[ ShowFlag ].ShowMenuItem,
			FExecuteAction::CreateSP( this, &SLevelViewport::ToggleShowFlag, SFData.EngineShowFlagIndex ),
			FCanExecuteAction(),
			FIsActionChecked::CreateSP( this, &SLevelViewport::IsShowFlagEnabled, SFData.EngineShowFlagIndex ) );
	}

	// Show Volumes
	{
		// Map 'Show All' and 'Hide All' commands
		CommandList.MapAction(
			FLevelViewportCommands::Get().ShowAllVolumes,
			FExecuteAction::CreateSP( this, &SLevelViewport::OnToggleAllVolumeActors, true ) );

		CommandList.MapAction(
			FLevelViewportCommands::Get().HideAllVolumes,
			FExecuteAction::CreateSP( this, &SLevelViewport::OnToggleAllVolumeActors, false ) );

		// Get all known volume classes
		TArray< UClass* > VolumeClasses;
		UUnrealEdEngine::GetSortedVolumeClasses(&VolumeClasses);

		for( int32 VolumeClassIndex = 0; VolumeClassIndex < VolumeClasses.Num(); ++VolumeClassIndex )
		{
			CommandList.MapAction(
				FLevelViewportCommands::Get().ShowVolumeCommands[ VolumeClassIndex ].ShowMenuItem,
				FExecuteAction::CreateSP( this, &SLevelViewport::ToggleShowVolumeClass, VolumeClassIndex ),
				FCanExecuteAction(),
				FIsActionChecked::CreateSP( this, &SLevelViewport::IsVolumeVisible, VolumeClassIndex ) );
		}
	}

	// Show Layers
	{
		// Map 'Show All' and 'Hide All' commands
		CommandList.MapAction(
			FLevelViewportCommands::Get().ShowAllLayers,
			FExecuteAction::CreateSP( this, &SLevelViewport::OnToggleAllLayers, true ) );

		CommandList.MapAction(
			FLevelViewportCommands::Get().HideAllLayers,
			FExecuteAction::CreateSP( this, &SLevelViewport::OnToggleAllLayers, false ) );
	}

	// Show Sprite Categories
	{
		// Map 'Show All' and 'Hide All' commands
		CommandList.MapAction(
			FLevelViewportCommands::Get().ShowAllSprites,
			FExecuteAction::CreateSP( this, &SLevelViewport::OnToggleAllSpriteCategories, true ) );

		CommandList.MapAction(
			FLevelViewportCommands::Get().HideAllSprites,
			FExecuteAction::CreateSP( this, &SLevelViewport::OnToggleAllSpriteCategories, false ) );

		// Bind each show flag to the same delegate.  We use the delegate payload system to figure out what show flag we are dealing with
		for( int32 CategoryIndex = 0; CategoryIndex < GUnrealEd->SpriteIDToIndexMap.Num(); ++CategoryIndex )
		{
			CommandList.MapAction(
				FLevelViewportCommands::Get().ShowSpriteCommands[ CategoryIndex ].ShowMenuItem,
				FExecuteAction::CreateSP( this, &SLevelViewport::ToggleSpriteCategory, CategoryIndex ),
				FCanExecuteAction(),
				FIsActionChecked::CreateSP( this, &SLevelViewport::IsSpriteCategoryVisible, CategoryIndex ) );
		}
	}

	// Show Stat Categories
	{
		// Map 'Hide All' command
		CommandList.MapAction(
			FLevelViewportCommands::Get().HideAllStats,
			FExecuteAction::CreateSP(this, &SLevelViewport::OnToggleAllStatCommands, false));

		for (auto StatCatIt = FLevelViewportCommands::Get().ShowStatCatCommands.CreateConstIterator(); StatCatIt; ++StatCatIt)
		{
			const TArray< FLevelViewportCommands::FShowMenuCommand >& ShowStatCommands = StatCatIt.Value();
			for (int32 StatIndex = 0; StatIndex < ShowStatCommands.Num(); ++StatIndex)
			{
				const FLevelViewportCommands::FShowMenuCommand& StatCommand = ShowStatCommands[StatIndex];
				BindStatCommand(StatCommand.ShowMenuItem, StatCommand.LabelOverride.ToString());
			}
		}

		// Bind a listener here for any additional stat commands that get registered later.
		FLevelViewportCommands::NewStatCommandDelegate.AddRaw(this, &SLevelViewport::BindStatCommand);
	}
}

void SLevelViewport::BindDropCommands( FUICommandList& CommandList )
{
	CommandList.MapAction( 
		FLevelViewportCommands::Get().ApplyMaterialToActor,
		FExecuteAction::CreateSP( this, &SLevelViewport::OnApplyMaterialToViewportTarget ) );
}


void SLevelViewport::BindStatCommand(const TSharedPtr<FUICommandInfo> InMenuItem, const FString& InCommandName)
{
	CommandList->MapAction(
		InMenuItem,
		FExecuteAction::CreateSP(this, &SLevelViewport::ToggleStatCommand, InCommandName),
		FCanExecuteAction(),
		FIsActionChecked::CreateSP(this, &SLevelViewport::IsStatCommandVisible, InCommandName));
}

const FSlateBrush* SLevelViewport::OnGetViewportBorderBrush() const
{
	const FSlateBrush* BorderBrush = NULL;
	if( FSlateApplication::Get().IsNormalExecution() )
	{
		// Only show the active border if we have a valid client, its the current client being edited and we arent in immersive (in immersive there is only one visible viewport)
		if( LevelViewportClient.IsValid() && LevelViewportClient.Get() == GCurrentLevelEditingViewportClient && !IsImmersive() )
		{
			BorderBrush = ActiveBorder;
		}
		else
		{
			BorderBrush = NoBorder;
		}

		// If a PIE/SIE/Editor transition just completed, then we'll draw a border effect to draw attention to it
		if( ViewTransitionAnim.IsPlaying() )
		{
			switch( ViewTransitionType )
			{
				case EViewTransition::FadingIn:
					BorderBrush = BlackBackground;
					break;

				case EViewTransition::StartingPlayInEditor:
					BorderBrush = StartingPlayInEditorBorder;
					break;

				case EViewTransition::StartingSimulate:
					BorderBrush = StartingSimulateBorder;
					break;

				case EViewTransition::ReturningToEditor:
					BorderBrush = ReturningToEditorBorder;
					break;
			}
		}
	}
	else
	{
		BorderBrush = DebuggingBorder;
	}

	return BorderBrush;
}

FSlateColor SLevelViewport::OnGetViewportBorderColorAndOpacity() const
{
	auto ColorAndOpacity = FLinearColor::White;
	if( FSlateApplication::Get().IsNormalExecution() )
	{
		if( ViewTransitionAnim.IsPlaying() )
		{
			ColorAndOpacity = FLinearColor( 1.0f, 1.0f, 1.0f, 1.0f - ViewTransitionAnim.GetLerp() );
		}
	}
	return ColorAndOpacity;
}

EVisibility SLevelViewport::OnGetViewportContentVisibility() const
{
	// Do not show any of the viewports inner slate content (active viewport borders, etc) when we are playing in editor and in immersive mode
	// as they are meaningless in that situation
	EVisibility BaseVisibility = SEditorViewport::OnGetViewportContentVisibility();
	if (BaseVisibility != EVisibility::Visible)
	{
		return BaseVisibility;
	}
	return IsPlayInEditorViewportActive() && IsImmersive() ? EVisibility::Collapsed : EVisibility::Visible;
}

EVisibility SLevelViewport::GetToolBarVisibility() const
{
	// Do not show the toolbar if this viewport has a play in editor session
	return IsPlayInEditorViewportActive() ? EVisibility::Collapsed : OnGetViewportContentVisibility();
}

EVisibility SLevelViewport::GetMaximizeToggleVisibility() const
{
	bool bIsMaximizeSupported = false;
	bool bShowMaximizeToggle = false;
	TSharedPtr<FLevelViewportLayout> LayoutPinned = ParentLayout.Pin();
	if (LayoutPinned.IsValid())
	{
		bIsMaximizeSupported = LayoutPinned->IsMaximizeSupported();
		bShowMaximizeToggle = !LayoutPinned->IsTransitioning();
	}

	// Do not show the maximize/minimize toggle when in immersive mode
	return (!bIsMaximizeSupported || IsImmersive()) ? EVisibility::Collapsed : (bShowMaximizeToggle ? EVisibility::Visible : EVisibility::Hidden);
}

EVisibility SLevelViewport::GetCloseImmersiveButtonVisibility() const
{
	// Do not show the Immersive toggle button when not in immersive mode
	return IsImmersive() ? EVisibility::Visible : EVisibility::Collapsed;
}

EVisibility SLevelViewport::GetTransformToolbarVisibility() const
{
	FLevelEditorModule& LevelEditorModule = FModuleManager::GetModuleChecked<FLevelEditorModule>( LevelEditorName );
	TSharedPtr<ILevelViewport> ActiveLevelViewport = LevelEditorModule.GetFirstActiveViewport();

	// Am I the ActiveLevelViewport? 
	if( ActiveLevelViewport.Get() == this )
	{
		// Only return visible if we are/were the active viewport. 
		return EVisibility::Visible;
	}

	return EVisibility::Hidden;
}

bool SLevelViewport::IsMaximized() const
{
	if( ParentLayout.IsValid() )
	{
		return ParentLayout.Pin()->IsViewportMaximized( *this );
	}

	// Assume the viewport is always maximized if we have no layout for some reason
	return true;
}

TSharedRef<FEditorViewportClient> SLevelViewport::MakeEditorViewportClient() 
{
	return LevelViewportClient.ToSharedRef();
}

TSharedPtr<SWidget> SLevelViewport::MakeViewportToolbar()
{

	// Build our toolbar level toolbar
	TSharedRef< SLevelViewportToolBar > ToolBar =
		SNew( SLevelViewportToolBar )
		.Viewport( SharedThis( this ) )
		.Visibility( this, &SLevelViewport::GetToolBarVisibility )
		.IsEnabled( FSlateApplication::Get().GetNormalExecutionAttribute() );


	return 
		SNew(SVerticalBox)
		.Visibility( EVisibility::SelfHitTestInvisible )
		+SVerticalBox::Slot()
		.AutoHeight()
		.VAlign(VAlign_Top)
		[
			ToolBar
		]
		+SVerticalBox::Slot()
		.VAlign(VAlign_Top)
		.HAlign(HAlign_Left)
		[
			SNew(SActorPilotViewportToolbar)
			.Viewport( SharedThis( this ) )
			.Visibility(this, &SLevelViewport::GetLockedIconVisibility)
		];
}

void SLevelViewport::OnUndo()
{
	GUnrealEd->Exec( GetWorld(), TEXT("TRANSACTION UNDO") );
}

void SLevelViewport::OnRedo()
{
	GUnrealEd->Exec(  GetWorld(), TEXT("TRANSACTION REDO") );
}

bool SLevelViewport::CanExecuteUndo() const
{
	return GUnrealEd->Trans->CanUndo() && FSlateApplication::Get().IsNormalExecution();
}

bool SLevelViewport::CanExecuteRedo() const
{
	return GUnrealEd->Trans->CanRedo() && FSlateApplication::Get().IsNormalExecution();
}

void SLevelViewport::OnAdvancedSettings()
{
	FModuleManager::LoadModuleChecked<ISettingsModule>("Settings").ShowViewer("Editor", "LevelEditor", "Viewport");
}

void SLevelViewport::OnToggleImmersive()
{
	if( ParentLayout.IsValid() ) 
	{
		bool bWantImmersive = !IsImmersive();
		bool bWantMaximize = IsMaximized();

		// We always want to animate in response to user-interactive toggling of maximized state
		const bool bAllowAnimation = true;

		ParentLayout.Pin()->RequestMaximizeViewport( SharedThis( this ), bWantMaximize, bWantImmersive, bAllowAnimation );
	}
}

bool SLevelViewport::IsImmersive() const
{
	if( ParentLayout.IsValid() )
	{
		return ParentLayout.Pin()->IsViewportImmersive( *this );
	}

	// Assume the viewport is not immersive if we have no layout for some reason
	return false;
}

void SLevelViewport::OnCreateCameraActor()
{		
	// Find the perspective viewport we were using
	FViewport* pViewPort = GEditor->GetActiveViewport();
	FLevelEditorViewportClient* ViewportClient = NULL;
	for( int32 iView = 0; iView < GEditor->LevelViewportClients.Num(); iView++ )
	{		
		if( GEditor->LevelViewportClients[ iView ]->IsPerspective() && GEditor->LevelViewportClients[ iView ]->Viewport == pViewPort )
		{
			ViewportClient = GEditor->LevelViewportClients[ iView ];
			break;
		}
	}

	if( ViewportClient == NULL )
	{
		// May fail to find viewport if shortcut key was pressed on an ortho viewport, if so early out.
		// This function only works on perspective viewports so new camera can match perspective camera.
		return;
	}

	const FScopedTransaction Transaction(NSLOCTEXT("LevelViewport", "CreateCameraHere", "Create Camera Here"));

	// Set new camera to match viewport
	ACameraActor* pNewCamera = ViewportClient->GetWorld()->SpawnActor<ACameraActor>();
	pNewCamera->SetActorLocation( ViewportClient->GetViewLocation(), false );
	pNewCamera->SetActorRotation( ViewportClient->GetViewRotation() );
	pNewCamera->CameraComponent->FieldOfView = ViewportClient->ViewFOV;

	// Deselect any currently selected actors
	GUnrealEd->SelectNone( true, true );
	GEditor->GetSelectedActors()->DeselectAll();
	GEditor->GetSelectedObjects()->DeselectAll();

	// Select newly created Camera
	TArray<UObject *> SelectedActors;
	GEditor->SelectActor( pNewCamera, true, false );
	SelectedActors.Add( pNewCamera );

	// Send notification about actors that may have changed
	ULevel::LevelDirtiedEvent.Broadcast();
	
	// Update the details window with the actors we have just selected
	GUnrealEd->UpdateFloatingPropertyWindowsFromActorList( SelectedActors );

	// Redraw viewports to show new camera
	GEditor->RedrawAllViewports();	
}

bool SLevelViewport::IsPerspectiveViewport() const
{
	bool bIsPerspective = false;
	FViewport* pViewPort = GEditor->GetActiveViewport();
	if( pViewPort && pViewPort->GetClient()->IsOrtho() == false )
	{
		bIsPerspective = true;
	}
	return bIsPerspective;
}

void SLevelViewport::OnTakeHighResScreenshot()
{
	HighResScreenshotDialog = SHighResScreenshotDialog::OpenDialog(ActiveViewport, CaptureRegionWidget);
}

void SLevelViewport::ToggleGameView()
{
	if( LevelViewportClient->IsPerspective() )
	{
		bool bGameViewEnable = !LevelViewportClient->IsInGameView();

		LevelViewportClient->SetGameView(bGameViewEnable);
	}
}

bool SLevelViewport::CanToggleGameView() const
{
	return LevelViewportClient->IsPerspective();
}

bool SLevelViewport::IsInGameView() const
{
	return LevelViewportClient->IsInGameView();
}


void SLevelViewport::ChangeBufferVisualizationMode( FName InName )
{
	LevelViewportClient->SetViewMode(VMI_VisualizeBuffer);
	LevelViewportClient->CurrentBufferVisualizationMode = InName;
}

bool SLevelViewport::IsBufferVisualizationModeSelected( FName InName ) const
{
	return LevelViewportClient->IsViewModeEnabled( VMI_VisualizeBuffer ) && LevelViewportClient->CurrentBufferVisualizationMode == InName;	
}

void SLevelViewport::OnToggleAllVolumeActors( bool bVisible )
{
	// Reinitialize the volume actor visibility flags to the new state.  All volumes should be visible if "Show All" was selected and hidden if it was not selected.
	LevelViewportClient->VolumeActorVisibility.Init( bVisible, LevelViewportClient->VolumeActorVisibility.Num() );

	// Update visibility based on the new state
	// All volume actor types should be taken since the user clicked on show or hide all to get here
	GUnrealEd->UpdateVolumeActorVisibility( NULL, LevelViewportClient.Get() );
}

/** Called when the user toggles a volume visibility from Volumes sub-menu. **/
void SLevelViewport::ToggleShowVolumeClass( int32 VolumeID )
{
	TArray< UClass* > VolumeClasses;
	UUnrealEdEngine::GetSortedVolumeClasses(&VolumeClasses);

	// Get the corresponding volume class for the clicked menu item.
	UClass *SelectedVolumeClass = VolumeClasses[ VolumeID ];

	LevelViewportClient->VolumeActorVisibility[ VolumeID ] = !LevelViewportClient->VolumeActorVisibility[ VolumeID ];

	// Update the found actors visibility based on the new bitfield
	GUnrealEd->UpdateVolumeActorVisibility( SelectedVolumeClass, LevelViewportClient.Get() );
}

/** Called to determine if vlume class is visible. **/
bool SLevelViewport::IsVolumeVisible( int32 VolumeID ) const
{
	return LevelViewportClient->VolumeActorVisibility[ VolumeID ];
}

/** Called when a user selects show or hide all from the layers visibility menu. **/
void SLevelViewport::OnToggleAllLayers( bool bVisible )
{	
	if (bVisible)
	{
		// clear all hidden layers
		LevelViewportClient->ViewHiddenLayers.Empty();
	}
	else
	{
		// hide them all
		TArray<FName> AllLayerNames;
		GEditor->Layers->AddAllLayerNamesTo(AllLayerNames);
		LevelViewportClient->ViewHiddenLayers = AllLayerNames;
	}

	// update actor visibility for this view
	GEditor->Layers->UpdatePerViewVisibility(LevelViewportClient.Get());

	LevelViewportClient->Invalidate(); 
}

/** Called when the user toggles a layer from Layers sub-menu. **/
void SLevelViewport::ToggleShowLayer( FName LayerName )
{
	int32 HiddenIndex = LevelViewportClient->ViewHiddenLayers.Find(LayerName);
	if ( HiddenIndex == INDEX_NONE )
	{
		LevelViewportClient->ViewHiddenLayers.Add(LayerName);
	}
	else
	{
		LevelViewportClient->ViewHiddenLayers.RemoveAt(HiddenIndex);
	}

	// update actor visibility for this view
	GEditor->Layers->UpdatePerViewVisibility(LevelViewportClient.Get(), LayerName);

	LevelViewportClient->Invalidate(); 
}

/** Called to determine if a layer is visible. **/
bool SLevelViewport::IsLayerVisible( FName LayerName ) const
{
	return LevelViewportClient->ViewHiddenLayers.Find(LayerName) == INDEX_NONE;
}

FViewport* SLevelViewport::GetActiveViewport() 
{ 
	return ActiveViewport->GetViewport(); 
}

void SLevelViewport::OnFocusViewportToSelection() 
{
	GUnrealEd->Exec( GetWorld(), TEXT("CAMERA ALIGN ACTIVEVIEWPORTONLY") );
}

/** Called when the user selects show or hide all from the sprite sub-menu. **/
void SLevelViewport::OnToggleAllSpriteCategories( bool bVisible )
{
	LevelViewportClient->SetAllSpriteCategoryVisibility( bVisible );
	LevelViewportClient->Invalidate();
}

/** Called when the user toggles a category from the sprite sub-menu. **/
void SLevelViewport::ToggleSpriteCategory( int32 CategoryID )
{
	LevelViewportClient->SetSpriteCategoryVisibility( CategoryID, !LevelViewportClient->GetSpriteCategoryVisibility( CategoryID ) );
	LevelViewportClient->Invalidate();
}

/** Called to determine if a category from the sprite sub-menu is visible. **/
bool SLevelViewport::IsSpriteCategoryVisible( int32 CategoryID ) const
{
	return LevelViewportClient->GetSpriteCategoryVisibility( CategoryID );
}

void SLevelViewport::OnToggleAllStatCommands( bool bVisible )
{
	check(bVisible == 0);
	// If it's in the array, it's visible so just toggle it again
	const TArray<FString>* EnabledStats = LevelViewportClient->GetEnabledStats();
	check(EnabledStats);
	while (EnabledStats->Num() > 0)
	{
		const FString& CommandName = EnabledStats->Last();
		ToggleStatCommand(CommandName);
	}
}

void SLevelViewport::OnUseDefaultShowFlags(bool bUseSavedDefaults)
{
	// cache off the current viewmode as it gets trashed when applying FEngineShowFlags()
	const EViewModeIndex CachedViewMode = LevelViewportClient->GetViewMode();

	// Setting show flags to the defaults should not stomp on the current viewmode settings.
	LevelViewportClient->SetGameView(false);

	// Get default save flags
	FEngineShowFlags EditorShowFlags(ESFIM_Editor);
	FEngineShowFlags GameShowFlags(ESFIM_Game);

	if (bUseSavedDefaults && !ConfigKey.IsEmpty())
	{
		FLevelEditorViewportInstanceSettings ViewportInstanceSettings;
		ViewportInstanceSettings.ViewportType = LevelViewportClient->ViewportType;

		// Get saved defaults if specified
		const FLevelEditorViewportInstanceSettings* const ViewportInstanceSettingsPtr = GetDefault<ULevelEditorViewportSettings>()->GetViewportInstanceSettings(ConfigKey);
		ViewportInstanceSettings = ViewportInstanceSettingsPtr ? *ViewportInstanceSettingsPtr : LoadLegacyConfigFromIni(ConfigKey, ViewportInstanceSettings);

		if (!ViewportInstanceSettings.EditorShowFlagsString.IsEmpty())
		{
			EditorShowFlags.SetFromString(*ViewportInstanceSettings.EditorShowFlagsString);
		}

		if (!ViewportInstanceSettings.GameShowFlagsString.IsEmpty())
		{
			GameShowFlags.SetFromString(*ViewportInstanceSettings.GameShowFlagsString);
		}
	}

	// this trashes the current viewmode!
	LevelViewportClient->EngineShowFlags = EditorShowFlags;
	// Restore the state of SelectionOutline based on user settings
	LevelViewportClient->EngineShowFlags.SelectionOutline = GetDefault<ULevelEditorViewportSettings>()->bUseSelectionOutline;
	LevelViewportClient->LastEngineShowFlags = GameShowFlags;

	// re-apply the cached viewmode, as it was trashed with FEngineShowFlags()
	ApplyViewMode(CachedViewMode, LevelViewportClient->IsPerspective(), LevelViewportClient->EngineShowFlags);
	ApplyViewMode(CachedViewMode, LevelViewportClient->IsPerspective(), LevelViewportClient->LastEngineShowFlags);

	// set volume / layer / sprite visibility defaults
	if (!bUseSavedDefaults)
	{
		LevelViewportClient->InitializeVisibilityFlags();
		GUnrealEd->UpdateVolumeActorVisibility(NULL, LevelViewportClient.Get());
		GEditor->Layers->UpdatePerViewVisibility(LevelViewportClient.Get());
	}

	LevelViewportClient->Invalidate();
}


void SLevelViewport::SetKeyboardFocusToThisViewport()
{
	if( ensure( ViewportWidget.IsValid() ) )
	{
			// Set keyboard focus directly
		FSlateApplication::Get().SetKeyboardFocus( ViewportWidget.ToSharedRef() );
	}
}


void SLevelViewport::SaveConfig(const FString& ConfigName)
{
	// When we startup the editor we always start it up in IsInGameView()=false mode
	FEngineShowFlags& EditorShowFlagsToSave = LevelViewportClient->IsInGameView() ? LevelViewportClient->LastEngineShowFlags : LevelViewportClient->EngineShowFlags;
	FEngineShowFlags& GameShowFlagsToSave = LevelViewportClient->IsInGameView() ? LevelViewportClient->EngineShowFlags : LevelViewportClient->LastEngineShowFlags;

	FLevelEditorViewportInstanceSettings ViewportInstanceSettings;
	ViewportInstanceSettings.ViewportType = LevelViewportClient->ViewportType;
	ViewportInstanceSettings.PerspViewModeIndex = LevelViewportClient->GetPerspViewMode();
	ViewportInstanceSettings.OrthoViewModeIndex = LevelViewportClient->GetOrthoViewMode();
	ViewportInstanceSettings.EditorShowFlagsString = EditorShowFlagsToSave.ToString();
	ViewportInstanceSettings.GameShowFlagsString = GameShowFlagsToSave.ToString();
	ViewportInstanceSettings.BufferVisualizationMode = LevelViewportClient->CurrentBufferVisualizationMode;
	ViewportInstanceSettings.ExposureSettings = LevelViewportClient->ExposureSettings;
	ViewportInstanceSettings.FOVAngle = LevelViewportClient->FOVAngle;
	ViewportInstanceSettings.bIsRealtime = LevelViewportClient->IsRealtime();
	ViewportInstanceSettings.bShowStats = LevelViewportClient->ShouldShowStats();
	if (GetDefault<ULevelEditorViewportSettings>()->bSaveEngineStats)
	{
		const TArray<FString>* EnabledStats = NULL;

		// If the selected viewport is currently hosting a PIE session, we need to make sure we copy to stats from the active viewport
		// Note: This happens if you close the editor while it's running because SwapStatCommands gets called after the config save when shutting down.
		if (IsPlayInEditorViewportActive())
		{
			EnabledStats = ActiveViewport->GetClient()->GetEnabledStats();
		}
		else
		{
			EnabledStats = LevelViewportClient->GetEnabledStats();
		}

		check(EnabledStats);
		ViewportInstanceSettings.EnabledStats = *EnabledStats;
	}
	GetMutableDefault<ULevelEditorViewportSettings>()->SetViewportInstanceSettings(ConfigName, ViewportInstanceSettings);
}


FLevelEditorViewportInstanceSettings SLevelViewport::LoadLegacyConfigFromIni(const FString& InConfigKey, const FLevelEditorViewportInstanceSettings& InDefaultSettings)
{
	FLevelEditorViewportInstanceSettings ViewportInstanceSettings = InDefaultSettings;

	const FString& IniSection = FLayoutSaveRestore::GetAdditionalLayoutConfigIni();

	{
		int32 ViewportTypeAsInt = ViewportInstanceSettings.ViewportType;
		GConfig->GetInt(*IniSection, *(InConfigKey + TEXT(".Type")), ViewportTypeAsInt, GEditorPerProjectIni);
		ViewportInstanceSettings.ViewportType = (ViewportTypeAsInt == -1 || ViewportTypeAsInt == 255) ? LVT_None : static_cast<ELevelViewportType>(ViewportTypeAsInt); // LVT_None used to be -1 or 255

		if(ViewportInstanceSettings.ViewportType == LVT_None)
		{
			ViewportInstanceSettings.ViewportType = LVT_Perspective;
		}
	}
	
	GConfig->GetString(*IniSection, *(InConfigKey + TEXT(".EditorShowFlags")), ViewportInstanceSettings.EditorShowFlagsString, GEditorPerProjectIni);
	GConfig->GetString(*IniSection, *(InConfigKey + TEXT(".GameShowFlags")), ViewportInstanceSettings.GameShowFlagsString, GEditorPerProjectIni);
		
	// A single view mode index has been deprecated in favor of separate perspective and orthographic settings
	EViewModeIndex LegacyViewModeIndex = VMI_Unknown;
	{
		int32 LegacyVMIAsInt = VMI_Unknown;
		GConfig->GetInt(*IniSection, *(InConfigKey+TEXT(".ViewModeIndex")), LegacyVMIAsInt, GEditorPerProjectIni);
		LegacyViewModeIndex = (LegacyVMIAsInt == -1) ? VMI_Unknown : static_cast<EViewModeIndex>(LegacyVMIAsInt); // VMI_Unknown used to be -1
	}

	if(!GConfig->GetInt(*IniSection, *(InConfigKey+TEXT(".PerspViewModeIndex")), (int32&)ViewportInstanceSettings.PerspViewModeIndex, GEditorPerProjectIni))
	{
		if(ViewportInstanceSettings.ViewportType == LVT_Perspective)
		{
			// This viewport may pre-date the ViewModeIndex setting (VMI_Unknown), if so, try to be backward compatible
			ViewportInstanceSettings.PerspViewModeIndex = (LegacyViewModeIndex == VMI_Unknown) ? FindViewMode(LevelViewportClient->EngineShowFlags) : LegacyViewModeIndex;
		}
		else
		{
			// Default to Lit for a perspective viewport
			ViewportInstanceSettings.PerspViewModeIndex = VMI_Lit;
		}
	}

	if(!GConfig->GetInt(*IniSection, *(InConfigKey+TEXT(".OrthoViewModeIndex")), (int32&)ViewportInstanceSettings.OrthoViewModeIndex, GEditorPerProjectIni))
	{
		// Default to Brush Wireframe for an orthographic viewport
		ViewportInstanceSettings.OrthoViewModeIndex = (ViewportInstanceSettings.ViewportType != LVT_Perspective && LegacyViewModeIndex != VMI_Unknown) ? LegacyViewModeIndex : VMI_BrushWireframe;
	}

	{
		FString BufferVisualizationModeString;
		if(GConfig->GetString(*IniSection, *(InConfigKey+TEXT(".BufferVisualizationMode")), BufferVisualizationModeString, GEditorPerProjectIni))
		{
			ViewportInstanceSettings.BufferVisualizationMode = *BufferVisualizationModeString;
		}
	}
	
	{
		FString ExposureSettingsString;
		if(GConfig->GetString(*IniSection, *(InConfigKey + TEXT(".ExposureSettings")), ExposureSettingsString, GEditorPerProjectIni))
		{
			ViewportInstanceSettings.ExposureSettings.SetFromString(*ExposureSettingsString);
		}
	}

	GConfig->GetBool(*IniSection, *(InConfigKey + TEXT(".bIsRealtime")), ViewportInstanceSettings.bIsRealtime, GEditorPerProjectIni);
	GConfig->GetBool(*IniSection, *(InConfigKey + TEXT(".bWantStats")), ViewportInstanceSettings.bShowStats, GEditorPerProjectIni);
	GConfig->GetBool(*IniSection, *(InConfigKey + TEXT(".bWantFPS")), ViewportInstanceSettings.bShowFPS_DEPRECATED, GEditorPerProjectIni);
	GConfig->GetFloat(*IniSection, *(InConfigKey + TEXT(".FOVAngle")), ViewportInstanceSettings.FOVAngle, GEditorPerProjectIni);

	return ViewportInstanceSettings;
}


void SLevelViewport::OnSetBookmark( int32 BookmarkIndex )
{
	GLevelEditorModeTools().SetBookmark( BookmarkIndex, LevelViewportClient.Get() );
}

void SLevelViewport::OnJumpToBookmark( int32 BookmarkIndex )
{
	const bool bShouldRestoreLevelVisibility = true;
	GLevelEditorModeTools().JumpToBookmark( BookmarkIndex, bShouldRestoreLevelVisibility, LevelViewportClient.Get() );
}

void SLevelViewport::OnClearBookMark( int32 BookmarkIndex )
{
	GLevelEditorModeTools().ClearBookmark( BookmarkIndex, LevelViewportClient.Get() );
}

void SLevelViewport::OnClearAllBookMarks()
{
	GLevelEditorModeTools().ClearAllBookmarks( LevelViewportClient.Get() );
}

void SLevelViewport::OnToggleAllowMatineePreview()
{
	// Reset the FOV of Viewport for cases where we have been previewing the matinee with a changing FOV
	LevelViewportClient->ViewFOV = LevelViewportClient->AllowMatineePreview() ? LevelViewportClient->ViewFOV : LevelViewportClient->FOVAngle;

	LevelViewportClient->SetAllowMatineePreview( !LevelViewportClient->AllowMatineePreview() );
	LevelViewportClient->Invalidate( false );
}

bool SLevelViewport::DoesAllowMatineePreview() const
{
	return LevelViewportClient->AllowMatineePreview();
}

void SLevelViewport::OnIncrementPositionGridSize()
{
	GEditor->GridSizeIncrement();
	GEditor->RedrawLevelEditingViewports();
}

void SLevelViewport::OnDecrementPositionGridSize()
{
	GEditor->GridSizeDecrement();
	GEditor->RedrawLevelEditingViewports();
}

void SLevelViewport::OnIncrementRotationGridSize()
{
	GEditor->RotGridSizeIncrement();
	GEditor->RedrawLevelEditingViewports();
}
	
void SLevelViewport::OnDecrementRotationGridSize()
{
	GEditor->RotGridSizeDecrement();
	GEditor->RedrawLevelEditingViewports();
}

void SLevelViewport::OnActorLockToggleFromMenu(AActor* Actor)
{
	if (Actor != NULL)
	{
		const bool bLockNewActor = Actor != LevelViewportClient->GetActiveActorLock().Get();

		// Lock the new actor if it wasn't the same actor that we just unlocked
		if (bLockNewActor)
		{
			// Unlock the previous actor
			OnActorUnlock();

			LockActorInternal(Actor);
		}
	}
}

bool SLevelViewport::IsActorLocked(const TWeakObjectPtr<AActor> Actor) const
{
	return LevelViewportClient->IsActorLocked(Actor);
}

bool SLevelViewport::IsAnyActorLocked() const
{
	return LevelViewportClient->IsAnyActorLocked();
}

void SLevelViewport::ToggleActorPilotCameraView()
{
	LevelViewportClient->bLockedCameraView = !LevelViewportClient->bLockedCameraView;
}

bool SLevelViewport::IsLockedCameraViewEnabled() const
{
	return LevelViewportClient->bLockedCameraView;
}

void SLevelViewport::FindSelectedInLevelScript()
{
	GUnrealEd->FindSelectedActorsInLevelScript();
}

bool SLevelViewport::CanFindSelectedInLevelScript() const
{
	AActor* Actor = GEditor->GetSelectedActors()->GetTop<AActor>();
	return (Actor != NULL);
}

void SLevelViewport::OnActorUnlock()
{
	if (AActor* LockedActor = LevelViewportClient->GetActiveActorLock().Get())
	{
		// Check to see if the locked actor was previously overriding the camera settings
		if (CanGetCameraInformationFromActor(LockedActor))
		{
			// Reset the settings
			LevelViewportClient->ViewFOV = LevelViewportClient->FOVAngle;
		}

		LevelViewportClient->SetActorLock(nullptr);

		// remove roll and pitch from camera when unbinding from actors
		GEditor->RemovePerspectiveViewRotation(true, true, false);

		// If we had a camera actor locked, and it was selected, then we should re-show the inset preview
		OnPreviewSelectedCamerasChange();
	}
}

bool SLevelViewport::CanExecuteActorUnlock() const
{
	return IsAnyActorLocked();
}

void SLevelViewport::OnActorLockSelected()
{
	USelection* ActorSelection = GEditor->GetSelectedActors();
	if (1 == ActorSelection->Num())
	{
		AActor* Actor = CastChecked<AActor>(ActorSelection->GetSelectedObject(0));
		LockActorInternal(Actor);
	}
}

bool SLevelViewport::CanExecuteActorLockSelected() const
{
	USelection* ActorSelection = GEditor->GetSelectedActors();
	if (1 == ActorSelection->Num())
	{
		return true;
	}
	return false;
}

bool SLevelViewport::IsSelectedActorLocked() const
{
	USelection* ActorSelection = GEditor->GetSelectedActors();
	if (1 == ActorSelection->Num() && IsAnyActorLocked())
	{
		AActor* Actor = CastChecked<AActor>(ActorSelection->GetSelectedObject(0));
		if (LevelViewportClient->GetActiveActorLock().Get() == Actor)
		{
			return true;
		}
	}
	return false;
}

float SLevelViewport::GetActorLockSceneOutlinerColumnWidth()
{
	return 18.0f;	// 16.0f for the icons and 2.0f padding
}

TSharedRef< ISceneOutlinerColumn > SLevelViewport::CreateActorLockSceneOutlinerColumn( ISceneOutliner& SceneOutliner ) const
{
	/**
	 * A custom column for the SceneOutliner which shows whether an actor is locked to a viewport
	 */
	class FCustomColumn : public ISceneOutlinerColumn
	{
	public:
		/**
		 *	Constructor
		 */
		FCustomColumn( const SLevelViewport* const InViewport )
			: Viewport(InViewport)
		{
		}

		virtual ~FCustomColumn()
		{
		}

		//////////////////////////////////////////////////////////////////////////
		// Begin ISceneOutlinerColumn Implementation

		virtual FName GetColumnID() override
		{
			return FName( "LockedToViewport" );
		}

		virtual SHeaderRow::FColumn::FArguments ConstructHeaderRowColumn() override
		{
			return SHeaderRow::Column( GetColumnID() )
				.FixedWidth(SLevelViewport::GetActorLockSceneOutlinerColumnWidth())
				[
					SNew( SSpacer )
				];
		}

		virtual const TSharedRef< SWidget > ConstructRowWidget( SceneOutliner::FTreeItemRef TreeItem, const STableRow<SceneOutliner::FTreeItemPtr>& InRow ) override
		{
			struct FConstructWidget : SceneOutliner::FColumnGenerator
			{
				const SLevelViewport* Viewport;
				FConstructWidget(const SLevelViewport* InViewport) : Viewport(InViewport) {}

				virtual TSharedRef<SWidget> GenerateWidget(SceneOutliner::FActorTreeItem& ActorItem) const override
				{
					AActor* Actor = ActorItem.Actor.Get();
					if (!Actor)
					{
						return SNullWidget::NullWidget;
					}

					const bool bLocked = Viewport->IsActorLocked(Actor);

					return SNew(SBox)
						.WidthOverride(SLevelViewport::GetActorLockSceneOutlinerColumnWidth())
						.Padding(FMargin(2.0f, 0.0f, 0.0f, 0.0f))
						[
							SNew(SImage)
							.Image(FEditorStyle::GetBrush(bLocked ? "PropertyWindow.Locked" : "PropertyWindow.Unlocked"))
							.ColorAndOpacity(bLocked ? FLinearColor::White : FLinearColor(1.0f, 1.0f, 1.0f, 0.5f))
						];	
				}
			};

			FConstructWidget Visitor(Viewport);
			TreeItem->Visit(Visitor);

			if (Visitor.Widget.IsValid())
			{
				return Visitor.Widget.ToSharedRef();	
			}
			else
			{
				return SNullWidget::NullWidget;
			}
		}

		// End ISceneOutlinerColumn Implementation
		//////////////////////////////////////////////////////////////////////////

	private:
		const SLevelViewport* Viewport;
	};

	return MakeShareable( new FCustomColumn( this ) );
}

void SLevelViewport::RedrawViewport( bool bInvalidateHitProxies )
{
	if ( bInvalidateHitProxies )
	{
		// Invalidate hit proxies and display pixels.
		LevelViewportClient->Viewport->Invalidate();
		
		// Also update preview viewports
		for( auto ActorPreviewIt = ActorPreviews.CreateConstIterator(); ActorPreviewIt; ++ActorPreviewIt )
		{
			auto& CurActorPreview = *ActorPreviewIt;

			CurActorPreview.LevelViewportClient->Viewport->Invalidate();
		}
	}
	else
	{
		// Invalidate only display pixels.
		LevelViewportClient->Viewport->InvalidateDisplay();

		// Also update preview viewports
		for( auto ActorPreviewIt = ActorPreviews.CreateConstIterator(); ActorPreviewIt; ++ActorPreviewIt )
		{
			auto& CurActorPreview = *ActorPreviewIt;

			CurActorPreview.LevelViewportClient->Viewport->InvalidateDisplay();
		}
	}
}

bool SLevelViewport::CanToggleMaximizeMode() const
{
	TSharedPtr<FLevelViewportLayout> ParentLayoutPinned = ParentLayout.Pin();
	return (ParentLayoutPinned.IsValid() && ParentLayoutPinned->IsMaximizeSupported() && !ParentLayoutPinned->IsTransitioning());
}

void  SLevelViewport::OnToggleMaximizeMode()
{
	OnToggleMaximize();
}

FReply SLevelViewport::OnToggleMaximize()
{
	TSharedPtr<FLevelViewportLayout> ParentLayoutPinned = ParentLayout.Pin();
	if (ParentLayoutPinned.IsValid() && ParentLayoutPinned->IsMaximizeSupported())
	{
		OnFloatingButtonClicked();

		bool bWantImmersive = IsImmersive();
		bool bWantMaximize = IsMaximized();

		//When in Immersive mode we always want to toggle back to normal editing mode while retaining the previous maximized state
		if( bWantImmersive )
		{
			bWantImmersive = false;
		}
		else
		{
			bWantMaximize = !bWantMaximize;
		}

		// We always want to animate in response to user-interactive toggling of maximized state
		const bool bAllowAnimation = true;

		ParentLayoutPinned->RequestMaximizeViewport(SharedThis(this), bWantMaximize, bWantImmersive, bAllowAnimation);
	}
	return FReply::Handled();
}


void SLevelViewport::MakeImmersive( const bool bWantImmersive, const bool bAllowAnimation )
{
	if( ensure( ParentLayout.IsValid() ) ) 
	{
		const bool bWantMaximize = IsMaximized();
		ParentLayout.Pin()->RequestMaximizeViewport( SharedThis( this ), bWantMaximize, bWantImmersive, bAllowAnimation );
	}
}

/**
 * Registers a game viewport with the Slate application so that specific messages can be routed directly to this level viewport if it is an active PIE viewport
 */
void SLevelViewport::RegisterGameViewportIfPIE()
{
	if(ActiveViewport->IsPlayInEditorViewport())
	{
		FSlateApplication::Get().RegisterGameViewport(ViewportWidget.ToSharedRef());
	}
}

bool SLevelViewport::HasPlayInEditorViewport() const
{
	return ActiveViewport->IsPlayInEditorViewport() || ( InactiveViewport.IsValid() && InactiveViewport->IsPlayInEditorViewport() );
}

bool SLevelViewport::IsPlayInEditorViewportActive() const
{
	return ActiveViewport->IsPlayInEditorViewport();
}

void SLevelViewport::OnActorSelectionChanged(const TArray<UObject*>& NewSelection, bool bForceRefresh)
{
	// On the first actor selection after entering Game View, enable the selection show flag
	if (IsVisible() && IsInGameView() && NewSelection.Num() != 0)
	{
		LevelViewportClient->EngineShowFlags.ModeWidgets = 1;
		LevelViewportClient->EngineShowFlags.Selection = 1;
		LevelViewportClient->EngineShowFlags.SelectionOutline = GetDefault<ULevelEditorViewportSettings>()->bUseSelectionOutline;
	}


	// Check to see if we have any actors that we should preview.  Only do this if we're the active level viewport client.
	// NOTE: We don't actively monitor which viewport is "current" and remove views, etc.  This ends up OK though because
	//       the camera PIP views will feel "sticky" in the viewport that was active when you last selected objects
	//       to preview!
	if (GetDefault<ULevelEditorViewportSettings>()->bPreviewSelectedCameras && GCurrentLevelEditingViewportClient == LevelViewportClient.Get())
	{
		PreviewSelectedCameraActors();
	}
	else
	{
		// We're no longer the active viewport client, so remove any existing previewed actors
		PreviewActors(TArray<AActor*>());
	}
}



void SLevelViewport::PreviewSelectedCameraActors()
{
	TArray<AActor*> ActorsToPreview;

	for (FSelectionIterator SelectionIt( *GEditor->GetSelectedActors()); SelectionIt; ++SelectionIt)
	{
		AActor* SelectedActor = CastChecked<AActor>( *SelectionIt );

		if (LevelViewportClient->IsLockedToActor(SelectedActor))
		{
			// If this viewport is already locked to the specified camera, then we don't need to do anything
		}
		else if (CanGetCameraInformationFromActor(SelectedActor))
		{
			ActorsToPreview.Add(SelectedActor);
		}
	}

	PreviewActors( ActorsToPreview );
}


class SActorPreview : public SCompoundWidget
{

public:

	~SActorPreview();

	SLATE_BEGIN_ARGS( SActorPreview )
		: _ViewportWidth( 240 ),
		  _ViewportHeight( 180 ) {}

		/** Width of the viewport */
		SLATE_ARGUMENT( int32, ViewportWidth )

		/** Height of the viewport */
		SLATE_ARGUMENT( int32, ViewportHeight )

		/** Actor being previewed.*/
		SLATE_ARGUMENT( TWeakObjectPtr< AActor >, PreviewActor )

		/** Parent Viewport this preview is part of.*/
		SLATE_ARGUMENT( TWeakPtr<SLevelViewport>, ParentViewport )

	SLATE_END_ARGS()

	/** Called by Slate to construct this widget */
	void Construct( const FArguments& InArgs );


	/** @return	Returns this actor preview's viewport widget */
	const TSharedRef< SViewport > GetViewportWidget() const
	{
		return ViewportWidget.ToSharedRef();
	}


	/** SWidget overrides */
	virtual void OnMouseEnter( const FGeometry& MyGeometry, const FPointerEvent& MouseEvent ) override;
	virtual void OnMouseLeave( const FPointerEvent& MouseEvent ) override;

	/** Highlight this preview window by flashing the border. Will replay the curve sequence if it is already in the middle of a highlight. */
	void Highlight();

private:

	/** Called when an actor in the world is selected */
	void OnActorSelected(UObject* InActor);

	/** @return Returns the color and opacity to use for this widget */
	FLinearColor GetColorAndOpacity() const;

	/** @return Returns the border color and opacity to use for this widget (FSlateColor version) */
	FSlateColor GetBorderColorAndOpacity() const;

	/** @return Gets the name of the preview actor.*/
	FText OnReadText() const;

	/** @return Gets the Width of the preview viewport.*/
	FOptionalSize OnReadWidth() const;

	/** @return Gets the Height of the preview viewport.*/
	FOptionalSize OnReadHeight() const;

	/** @return Get the Width to wrap the preview actor name at.*/
	float OnReadTextWidth() const;

	/** Called when the pin preview button is clicked */
	FReply OnTogglePinnedButtonClicked();

	/** Swap between the pinned and unpinned icons */
	const FSlateBrush* GetPinButtonIconBrush() const;

	/** @return the tooltip to display when hovering over the pin button */
	FText GetPinButtonToolTipText() const;
	
	/** Viewport widget for this actor preview */
	TSharedPtr< SViewport > ViewportWidget;

	/** Actor being previewed.*/
	TWeakObjectPtr< AActor > PreviewActorPtr;

	/** Parent Viewport this preview is part of.*/
	TWeakPtr<SLevelViewport> ParentViewport;

	/** Curve sequence for fading in and out */
	FCurveSequence FadeSequence;

	/** Curve sequence for flashing the border (highlighting) when a pinned preview is re-selected */
	FCurveSequence HighlightSequence;

	/** Padding around the preview actor name */
	static const float PreviewTextPadding;
};

const float SActorPreview::PreviewTextPadding = 3.0f;

SActorPreview::~SActorPreview()
{
	USelection::SelectObjectEvent.RemoveAll(this);
}

void SActorPreview::Construct( const FArguments& InArgs )
{
	const int32 HorizSpacingBetweenViewports = 18;
	const int32 PaddingBeforeBorder = 6;

	USelection::SelectObjectEvent.AddRaw(this, &SActorPreview::OnActorSelected);

	// We don't want the border to be hit testable, since it would just get in the way of other
	// widgets that are added to the viewport overlay.
	this->SetVisibility(EVisibility::SelfHitTestInvisible);

	this->ChildSlot
	[
		SNew(SBorder)
		.Padding(0)

		.Visibility(EVisibility::SelfHitTestInvisible)

		.BorderImage(FEditorStyle::GetBrush("NoBorder"))
		.HAlign(HAlign_Right)
		.VAlign(VAlign_Bottom)
		.Padding(FMargin(0, 0, PaddingBeforeBorder, PaddingBeforeBorder))
		[
			SNew( SOverlay )
			+SOverlay::Slot()
			[
				SNew( SBorder )
					// We never want the user to be able to interact with this viewport.  Clicks should go right though it!
					.Visibility( EVisibility::HitTestInvisible )

					.Padding( 16.0f )
					.BorderImage( FEditorStyle::GetBrush( "UniformShadow_Tint" ) )

					.BorderBackgroundColor( this, &SActorPreview::GetBorderColorAndOpacity )
					.ColorAndOpacity( this, &SActorPreview::GetColorAndOpacity )

					[
						SNew( SBox )
							.WidthOverride( this, &SActorPreview::OnReadWidth )
							.HeightOverride(this, &SActorPreview::OnReadHeight )
							[
								SNew( SOverlay )
									+SOverlay::Slot()
									[
										SAssignNew( ViewportWidget, SViewport )
											.RenderDirectlyToWindow( false )
											.IsEnabled( FSlateApplication::Get().GetNormalExecutionAttribute() )
											.EnableGammaCorrection( false )		// Scene rendering handles gamma correction
											.EnableBlending( true )
									]
									
									+SOverlay::Slot()
									.Padding(PreviewTextPadding)
									.HAlign(HAlign_Center)
									[
										SNew( STextBlock )
											.Text( this, &SActorPreview::OnReadText )
											.Font( FSlateFontInfo( FPaths::EngineContentDir() / TEXT("Slate/Fonts/Roboto-Bold.ttf"), 10 ) )
											.ShadowOffset( FVector2D::UnitVector )
											.WrapTextAt( this, &SActorPreview::OnReadTextWidth )
									]
							]
					]
				
			]
			+SOverlay::Slot()
			.HAlign(HAlign_Left)
			.VAlign(VAlign_Bottom)
			.Padding( 24.0f )
			[
				// Create a button to pin/unpin this viewport
				SNew( SButton )
					.ContentPadding(0)
					.ForegroundColor( FSlateColor::UseForeground() )
					.ButtonStyle( FEditorStyle::Get(), "ToggleButton" )

					.IsFocusable(false)
					[
						SNew( SImage )
							.Visibility( EVisibility::Visible )	
							.Image( this, &SActorPreview::GetPinButtonIconBrush )
					]

					// Bind the button's "on clicked" event to our object's method for this
					.OnClicked( this, &SActorPreview::OnTogglePinnedButtonClicked )
					.Visibility( EVisibility::Visible )

					// Pass along the block's tool-tip string
					.ToolTipText( this, &SActorPreview::GetPinButtonToolTipText )
			]
		]
	];

	// Setup animation curve for fading in and out.  Note that we add a bit of lead-in time on the fade-in
	// to avoid hysteresis as the user moves the mouse over the view
	{
		/** The amount of time to wait before fading in after the mouse leaves */
		const float TimeBeforeFadingIn = 0.5f;

		/** The amount of time spent actually fading in or out */
		const float FadeTime = 0.25f;

		FadeSequence = FCurveSequence( TimeBeforeFadingIn, FadeTime );

		// Start fading in!
		FadeSequence.Play(this->AsShared(), false, TimeBeforeFadingIn);	// Skip the initial time delay and just fade straight in
	}

	HighlightSequence = FCurveSequence(0.f, 0.5f, ECurveEaseFunction::Linear);

	PreviewActorPtr = InArgs._PreviewActor;
	ParentViewport = InArgs._ParentViewport;
}

FReply SActorPreview::OnTogglePinnedButtonClicked()
{
	TSharedPtr<SLevelViewport> ParentViewportPtr = ParentViewport.Pin();

	if (ParentViewportPtr.IsValid())
	{
			ParentViewportPtr->ToggleActorPreviewIsPinned(PreviewActorPtr);
	}

	return FReply::Handled();
}

const FSlateBrush* SActorPreview::GetPinButtonIconBrush() const
{
	const FSlateBrush* IconBrush = NULL;

	TSharedPtr<SLevelViewport> ParentViewportPtr = ParentViewport.Pin();

	if (ParentViewportPtr.IsValid())
	{
		if ( ParentViewportPtr->IsActorPreviewPinned(PreviewActorPtr) )
		{
			IconBrush = FEditorStyle::GetBrush( "ViewportActorPreview.Pinned" );
		}
		else
		{
			IconBrush = FEditorStyle::GetBrush( "ViewportActorPreview.Unpinned" );
		}

	}

	return IconBrush;
}

FText SActorPreview::GetPinButtonToolTipText() const
{
	FText CurrentToolTipText = LOCTEXT("PinPreviewActorTooltip", "Pin Preview");

	TSharedPtr<SLevelViewport> ParentViewportPtr = ParentViewport.Pin();

	if (ParentViewportPtr.IsValid())
	{
		if ( ParentViewportPtr->IsActorPreviewPinned(PreviewActorPtr) )
		{
			CurrentToolTipText = LOCTEXT("UnpinPreviewActorTooltip", "Unpin Preview");
		}
	}
		
	return CurrentToolTipText;
}


void SActorPreview::OnMouseEnter( const FGeometry& MyGeometry, const FPointerEvent& MouseEvent )
{
	SCompoundWidget::OnMouseEnter( MyGeometry, MouseEvent );

	// The viewport could potentially be moved around inside the toolbar when the mouse is captured
	// If that is the case we do not play the fade transition
	if( !FSlateApplication::Get().IsUsingHighPrecisionMouseMovment() )
	{
		if( FadeSequence.IsPlaying() )
		{
			if( FadeSequence.IsForward() )
			{
				// Fade in is already playing so just force the fade out curve to the end so we don't have a "pop" 
				// effect from quickly resetting the alpha
				FadeSequence.JumpToStart();
			}
		}
		else
		{
			FadeSequence.PlayReverse(this->AsShared());
		}
	}
}


void SActorPreview::OnMouseLeave( const FPointerEvent& MouseEvent )
{
	SCompoundWidget::OnMouseLeave( MouseEvent );

	// The viewport could potentially be moved around inside the toolbar when the mouse is captured
	// If that is the case we do not play the fade transition
	if( !FSlateApplication::Get().IsUsingHighPrecisionMouseMovment() )
	{
		if( FadeSequence.IsPlaying() )
		{
			if( FadeSequence.IsInReverse() )
			{
				FadeSequence.Reverse();
			}
		}
		else
		{
			FadeSequence.Play(this->AsShared());
		}
	}

	// Now is a good time to check if we need to remove any PreviewActors that might have been un-pinned
	TSharedPtr<SLevelViewport> ParentViewportPtr = ParentViewport.Pin();
	if (ParentViewportPtr.IsValid())
	{
		ParentViewportPtr->OnPreviewSelectedCamerasChange();
	}
}


FLinearColor SActorPreview::GetColorAndOpacity() const
{
	FLinearColor Color = FLinearColor::White;
	
	const float HoveredOpacity = 0.4f;
	const float NonHoveredOpacity = 1.0f;

	Color.A = FMath::Lerp( HoveredOpacity, NonHoveredOpacity, FadeSequence.GetLerp() );

	return Color;
}

void SActorPreview::OnActorSelected(UObject* InActor)
{
	if (InActor && InActor == PreviewActorPtr && InActor->IsSelected())
	{
		TSharedPtr<SLevelViewport> ParentViewportPtr = ParentViewport.Pin();
		const bool bIsPreviewPinned = ParentViewportPtr.IsValid() && ParentViewportPtr->IsActorPreviewPinned(PreviewActorPtr);

		if (bIsPreviewPinned)
		{
			Highlight();
		}
	}
}

void SActorPreview::Highlight()
{
	HighlightSequence.JumpToStart();
	HighlightSequence.Play(this->AsShared());
}

FSlateColor SActorPreview::GetBorderColorAndOpacity() const
{
	FLinearColor Color(0.f, 0.f, 0.f, 0.5f);

	if (HighlightSequence.IsPlaying())
	{
		static const FName SelectionColorName("SelectionColor");
		const FLinearColor SelectionColor = FEditorStyle::Get().GetSlateColor(SelectionColorName).GetSpecifiedColor().CopyWithNewOpacity(0.5f);
		
		const float Interp = FMath::Sin(HighlightSequence.GetLerp()*6*PI) / 2 + 1;
		Color = FMath::Lerp(SelectionColor, Color, Interp);
	}
	
	return Color;
}

FText SActorPreview::OnReadText() const
{
	if( PreviewActorPtr.IsValid() )
	{
		return FText::FromString(PreviewActorPtr.Get()->GetActorLabel());
	}
	else
	{
		return FText::GetEmpty();
	}
}

FOptionalSize SActorPreview::OnReadWidth() const
{
	const float PreviewHeight = OnReadHeight().Get();

	// See if the preview actor wants to constrain the aspect ratio first
	if (AActor* PreviewActor = PreviewActorPtr.Get())
	{
		FMinimalViewInfo CameraInfo;
		if (SLevelViewport::GetCameraInformationFromActor(PreviewActor, /*out*/ CameraInfo))
		{
			if (CameraInfo.bConstrainAspectRatio && (CameraInfo.AspectRatio > 0.0f))
			{
				return PreviewHeight * CameraInfo.AspectRatio;
			}
		}
	}

	// Otherwise try to match the parent viewport's aspect ratio
	if ( ParentViewport.IsValid() )
	{
		return PreviewHeight * ParentViewport.Pin()->GetActiveViewport()->GetDesiredAspectRatio();
	}

	return PreviewHeight * 1.7777f;
}

FOptionalSize SActorPreview::OnReadHeight() const
{
	const float MinimumHeight = 32;
	// Also used as parent height in case valid parent viewport is not set
	const float MaximumHeight = 428;
	// Used to make sure default viewport scale * parent viewport height = roughly same size as original windows
	const float PreviewScalingFactor = 0.06308f;

	float ParentHeight = MaximumHeight;
	if ( ParentViewport.IsValid() )
	{
		ParentHeight = ParentViewport.Pin()->GetActiveViewport()->GetSizeXY().Y;
	}
	return FMath::Clamp( GetDefault<ULevelEditorViewportSettings>()->CameraPreviewSize * ParentHeight * PreviewScalingFactor, MinimumHeight, MaximumHeight );
}

float SActorPreview::OnReadTextWidth() const
{
	return OnReadWidth().Get() - (PreviewTextPadding*2.0f);
}

void SLevelViewport::PreviewActors( const TArray< AActor* >& ActorsToPreview )
{
	TArray< AActor* > NewActorsToPreview;
	TArray< AActor* > ActorsToStopPreviewing;

	// Look for actors that we no longer want to preview
	for( auto ActorPreviewIt = ActorPreviews.CreateConstIterator(); ActorPreviewIt; ++ActorPreviewIt )
	{
		auto ExistingActor = ActorPreviewIt->Actor.Get();
		if( ExistingActor != NULL )
		{
			auto bShouldKeepActor = false;
			for( auto ActorIt = ActorsToPreview.CreateConstIterator(); ActorIt; ++ActorIt )
			{
				auto CurActor = *ActorIt;
				if( CurActor != NULL && CurActor == ExistingActor )
				{
					bShouldKeepActor = true;
					break;
				}
			}

			if( !bShouldKeepActor )
			{
				// We were asked to stop previewing this actor
				ActorsToStopPreviewing.AddUnique( ExistingActor );
			}
		}
	}

	// Look for any new actors that we aren't previewing already
	for( auto ActorIt = ActorsToPreview.CreateConstIterator(); ActorIt; ++ActorIt )
	{
		auto CurActor = *ActorIt;

		// Check to see if we're already previewing this actor.  If we are, we'll just skip it
		auto bIsAlreadyPreviewed = false;
		for( auto ExistingPreviewIt = ActorPreviews.CreateConstIterator(); ExistingPreviewIt; ++ExistingPreviewIt )
		{
			// There could be null actors in this list as we haven't actually removed them yet.
			auto ExistingActor = ExistingPreviewIt->Actor.Get();
			if( ExistingActor != NULL && CurActor == ExistingActor )
			{
				// Already previewing this actor.  Ignore it.
				bIsAlreadyPreviewed = true;
				break;
			}
		}

		if( !bIsAlreadyPreviewed )
		{
			// This is a new actor that we want to preview.  Let's set that up.
			NewActorsToPreview.Add( CurActor );
		}
	}


	// Kill any existing actor previews that we don't want or have expired
	for( int32 PreviewIndex = 0; PreviewIndex < ActorPreviews.Num(); ++PreviewIndex )
	{
		AActor* ExistingActor = ActorPreviews[PreviewIndex].Actor.Get();
		if ( ExistingActor == NULL )
		{
			// decrement index so we don't miss next preview after deleting
			RemoveActorPreview( PreviewIndex-- );
		}
		else
		{
			if ( !ActorPreviews[PreviewIndex].bIsPinned )
			{
				for( auto ActorIt = ActorsToStopPreviewing.CreateConstIterator(); ActorIt; ++ActorIt )
				{
					auto CurActor = *ActorIt;
					if( ExistingActor == CurActor )
					{
						// Remove this preview!
						// decrement index so we don't miss next preview after deleting
						RemoveActorPreview( PreviewIndex-- );
						break;
					}
				}
			}
		}
	}

	// Create previews for any actors that we need to
	if( NewActorsToPreview.Num() > 0 )
	{
		for( auto ActorIt = NewActorsToPreview.CreateConstIterator(); ActorIt; ++ActorIt )
		{
			auto CurActor = *ActorIt;

			TSharedPtr< FLevelEditorViewportClient > ActorPreviewLevelViewportClient = MakeShareable( new FLevelEditorViewportClient(SharedThis(this)) );
			{
				// NOTE: We don't bother setting ViewLocation, ViewRotation, etc, here.  This is because we'll call
				//       PushControllingActorDataToViewportClient() below which will do this!

				// ParentLevelEditor is used for summoning context menus, which should never happen for these preview
				// viewports, but we'll keep the relationship intact anyway.
				ActorPreviewLevelViewportClient->ParentLevelEditor = ParentLevelEditor.Pin();

				ActorPreviewLevelViewportClient->ViewportType = LVT_Perspective;
				ActorPreviewLevelViewportClient->bSetListenerPosition = false;	// Preview viewports never be a listener

				// Never draw the axes indicator in these small viewports
				ActorPreviewLevelViewportClient->bDrawAxes = false;

				// Default to "game" show flags for camera previews
				// Still draw selection highlight though
				ActorPreviewLevelViewportClient->EngineShowFlags = FEngineShowFlags(ESFIM_Game);
				ActorPreviewLevelViewportClient->EngineShowFlags.Selection = 1;
				ActorPreviewLevelViewportClient->LastEngineShowFlags = FEngineShowFlags(ESFIM_Editor);
				
				// We don't use view modes for preview viewports
				ActorPreviewLevelViewportClient->SetViewMode( VMI_Unknown );

				// User should never be able to interact with this viewport
				ActorPreviewLevelViewportClient->bDisableInput = true;

				// Never allow Matinee to possess these views
				ActorPreviewLevelViewportClient->SetAllowMatineePreview( false );

				// Our preview viewport is always visible if our owning SLevelViewport is visible, so we hook up
				// to the same IsVisible method
				ActorPreviewLevelViewportClient->VisibilityDelegate.BindSP( this, &SLevelViewport::IsVisible );

				// Push actor transform to view.  From here on out, this will happen automatically in FLevelEditorViewportClient::Tick.
				// The reason we allow the viewport client to update this is to avoid off-by-one-frame issues when dragging actors around.
				ActorPreviewLevelViewportClient->SetActorLock( CurActor );
				ActorPreviewLevelViewportClient->UpdateViewForLockedActor();
			}

			TSharedPtr< SActorPreview > ActorPreviewWidget = SNew(SActorPreview)
				.PreviewActor(CurActor)
				.ParentViewport(SharedThis(this));

			auto ActorPreviewViewportWidget = ActorPreviewWidget->GetViewportWidget();

			TSharedPtr< FSceneViewport > ActorPreviewSceneViewport = MakeShareable( new FSceneViewport( ActorPreviewLevelViewportClient.Get(), ViewportWidget ) );
			{
				ActorPreviewLevelViewportClient->Viewport = ActorPreviewSceneViewport.Get();
				ActorPreviewViewportWidget->SetViewportInterface( ActorPreviewSceneViewport.ToSharedRef() );
			}

			FViewportActorPreview& NewActorPreview = *new( ActorPreviews ) FViewportActorPreview;
			NewActorPreview.Actor = CurActor;
			NewActorPreview.LevelViewportClient = ActorPreviewLevelViewportClient;
			NewActorPreview.SceneViewport = ActorPreviewSceneViewport;
			NewActorPreview.PreviewWidget = ActorPreviewWidget;
			NewActorPreview.bIsPinned = false;

			// Add our new widget to our viewport's overlay
			// @todo camerapip: Consider using a canvas instead of an overlay widget -- our viewports get SQUASHED when the view shrinks!
			ActorPreviewHorizontalBox->AddSlot()
			.AutoWidth()
			[
				ActorPreviewWidget.ToSharedRef()
			];
		}

		// OK, at least one new preview viewport was added, so update settings for all views immediately.
		// This will also be repeated every time the SLevelViewport is ticked, just to make sure that
		// feature such as "real-time" mode stay in sync.
		UpdateActorPreviewViewports();
	}
}

void SLevelViewport::ToggleActorPreviewIsPinned(TWeakObjectPtr<AActor> ActorToTogglePinned)
{
	if (ActorToTogglePinned.IsValid())
	{
		AActor* ActorToTogglePinnedPtr = ActorToTogglePinned.Get();

		for (FViewportActorPreview& ActorPreview : ActorPreviews)
		{
			if ( ActorPreview.Actor.IsValid() )
			{
				if ( ActorToTogglePinnedPtr == ActorPreview.Actor.Get() )
				{
					ActorPreview.ToggleIsPinned();
				}
			}
		}
	}
}



bool SLevelViewport::IsActorPreviewPinned( TWeakObjectPtr<AActor> PreviewActor )
{
	if (PreviewActor.IsValid())
	{
		AActor* PreviewActorPtr = PreviewActor.Get();

		for (FViewportActorPreview& ActorPreview : ActorPreviews)
		{
			if ( ActorPreview.Actor.IsValid() )
			{
				if ( PreviewActorPtr == ActorPreview.Actor.Get() )
				{
					return ActorPreview.bIsPinned;
				}
			}
		}
	}

	return false;
}

void SLevelViewport::UpdateActorPreviewViewports()
{
	// Look for actors that we no longer want to preview
	for( auto ActorPreviewIt = ActorPreviews.CreateConstIterator(); ActorPreviewIt; ++ActorPreviewIt )
	{
		auto& CurActorPreview = *ActorPreviewIt;

		CurActorPreview.LevelViewportClient->SetRealtime( LevelViewportClient->IsRealtime() );
		CurActorPreview.LevelViewportClient->bDrawBaseInfo = LevelViewportClient->bDrawBaseInfo;
		CurActorPreview.LevelViewportClient->bDrawVertices = LevelViewportClient->bDrawVertices;
		CurActorPreview.LevelViewportClient->EngineShowFlags.SelectionOutline = LevelViewportClient->EngineShowFlags.SelectionOutline;
		CurActorPreview.LevelViewportClient->EngineShowFlags.CompositeEditorPrimitives = LevelViewportClient->EngineShowFlags.CompositeEditorPrimitives;
	}
}

void SLevelViewport::OnPreviewSelectedCamerasChange()
{
	// Check to see if previewing selected cameras is enabled and if we're the active level viewport client.
	if (GetDefault<ULevelEditorViewportSettings>()->bPreviewSelectedCameras && GCurrentLevelEditingViewportClient == LevelViewportClient.Get())
	{
		PreviewSelectedCameraActors();
	}
	else
	{
		// We're either not the active viewport client or preview selected cameras option is disabled, so remove any existing previewed actors
		PreviewActors(TArray<AActor*>());
	}
}

void SLevelViewport::SetDeviceProfileString( const FString& ProfileName )
{
	DeviceProfile = ProfileName;
}

bool SLevelViewport::IsDeviceProfileStringSet( FString ProfileName ) const
{
	return DeviceProfile == ProfileName;
}

FString SLevelViewport::GetDeviceProfileString( ) const
{
	return DeviceProfile;
}

FText SLevelViewport::GetCurrentFeatureLevelPreviewText( bool bDrawOnlyLabel ) const
{
	FText LabelName;
	FText FeatureLevelText;

	if (bDrawOnlyLabel)
	{
		LabelName = LOCTEXT("FeatureLevelLabel", "Feature Level:");
	}
	else
	{
		auto* World = GetWorld();
		if (World != nullptr)
		{
			const auto FeatureLevel = World->FeatureLevel;
			if (FeatureLevel != GMaxRHIFeatureLevel)
			{
				FName FeatureLevelName;
				GetFeatureLevelName(FeatureLevel, FeatureLevelName);
				FeatureLevelText = FText::Format(LOCTEXT("FeatureLevel", "{0}"), FText::FromName(FeatureLevelName));
			}
		}
	}
	
	if (bDrawOnlyLabel)
	{
		return LabelName;
	}

	return FeatureLevelText;
}

FText SLevelViewport::GetCurrentLevelText( bool bDrawOnlyLabel ) const
{
	// Display the current level and current level grid volume in the status bar
	FText LabelName;
	FText CurrentLevelName;

	
	if( ActiveViewport.IsValid() && (&GetLevelViewportClient() == GCurrentLevelEditingViewportClient) && GetWorld() && GetWorld()->GetCurrentLevel() != nullptr )
	{
		if( ActiveViewport->GetPlayInEditorIsSimulate() || !ActiveViewport->GetClient()->GetWorld()->IsGameWorld() )
		{
			if(bDrawOnlyLabel)
			{
				LabelName = LOCTEXT("CurrentLevelLabel", "Level:");
			}
			else
			{
				// Get the level name (without the number at the end)
				FText ActualLevelName = FText::FromString(FPackageName::GetShortFName(GetWorld()->GetCurrentLevel()->GetOutermost()->GetFName()).GetPlainNameString());

				if(GetWorld()->GetCurrentLevel() == GetWorld()->PersistentLevel)
				{
					FFormatNamedArguments Args;
					Args.Add(TEXT("ActualLevelName"), ActualLevelName);
					CurrentLevelName = FText::Format(LOCTEXT("LevelName", "{0} (Persistent)"), ActualLevelName);
				}
				else
				{
					CurrentLevelName = ActualLevelName;
				}
			}

			if(bDrawOnlyLabel)
			{
				return LabelName;
			}
		}
	}

	return CurrentLevelName;
}

EVisibility SLevelViewport::GetCurrentLevelTextVisibility() const
{
	EVisibility ContentVisibility = OnGetViewportContentVisibility();
	if (ContentVisibility == EVisibility::Visible)
	{
		ContentVisibility = EVisibility::SelfHitTestInvisible;
	}
	return (&GetLevelViewportClient() == GCurrentLevelEditingViewportClient) ? ContentVisibility : EVisibility::Collapsed;
}

EVisibility SLevelViewport::GetCurrentFeatureLevelPreviewTextVisibility() const
{
	if (GetWorld())
	{
		return (GetWorld()->FeatureLevel != GMaxRHIFeatureLevel) ? EVisibility::SelfHitTestInvisible : EVisibility::Collapsed;
	}
	else
	{
		return EVisibility::Collapsed;
	}
}

EVisibility SLevelViewport::GetViewportControlsVisibility() const
{
	// Do not show the controls if this viewport has a play in editor session
	// or is not the current viewport
	return (&GetLevelViewportClient() == GCurrentLevelEditingViewportClient && !IsPlayInEditorViewportActive()) ? OnGetViewportContentVisibility() : EVisibility::Collapsed;
}

void SLevelViewport::OnSetViewportConfiguration(FName ConfigurationName)
{
	TSharedPtr<FLevelViewportLayout> LayoutPinned = ParentLayout.Pin();
	if (LayoutPinned.IsValid())
	{
		TSharedPtr<FLevelViewportTabContent> ViewportTabPinned = LayoutPinned->GetParentTabContent().Pin();
		if (ViewportTabPinned.IsValid())
		{
			ViewportTabPinned->SetViewportConfiguration(ConfigurationName);
			// Viewport clients are going away.  Any current one is invalid.
			GCurrentLevelEditingViewportClient = nullptr;
			FSlateApplication::Get().DismissAllMenus();
		}
	}
}

bool SLevelViewport::IsViewportConfigurationSet(FName ConfigurationName) const
{
	TSharedPtr<FLevelViewportLayout> LayoutPinned = ParentLayout.Pin();
	if (LayoutPinned.IsValid())
	{
		TSharedPtr<FLevelViewportTabContent> ViewportTabPinned = LayoutPinned->GetParentTabContent().Pin();
		if (ViewportTabPinned.IsValid())
		{
			return ViewportTabPinned->IsViewportConfigurationSet(ConfigurationName);
		}
	}
	return false;
}

void SLevelViewport::StartPlayInEditorSession(UGameViewportClient* PlayClient, const bool bInSimulateInEditor)
{
	check( !HasPlayInEditorViewport() );

	check( !InactiveViewport.IsValid() );

	// Ensure our active viewport is for level editing
	check( ActiveViewport->GetClient() == LevelViewportClient.Get() );
	// Save camera settings that may be adversely affected by PIE, so that they may be restored later
	LevelViewportClient->PrepareCameraForPIE();

	// Here we will swap the editor viewport client out for the client for the play in editor session
	InactiveViewport = ActiveViewport;
	// Store the content in the viewport widget (editor tool bar etc) so we can show the game UI content if it has any
	InactiveViewportWidgetEditorContent = ViewportWidget->GetContent();

	// Remove keyboard focus to send a focus lost message to the widget to clean up any saved state from the viewport interface thats about to be swapped out
	// Focus will be set when the game viewport is registered
	FSlateApplication::Get().ClearKeyboardFocus(EFocusCause::SetDirectly);

	ActiveViewport = MakeShareable( new FSceneViewport( PlayClient, ViewportWidget ) );
	ActiveViewport->SetPlayInEditorViewport( true );

	// Whether to start with the game taking mouse control or leaving it shown in the editor
	ActiveViewport->SetPlayInEditorGetsMouseControl(GetDefault<ULevelEditorPlaySettings>()->GameGetsMouseControl);
	ActiveViewport->SetPlayInEditorIsSimulate(bInSimulateInEditor);
	
	ActiveViewport->OnPlayWorldViewportSwapped( *InactiveViewport );

	PlayClient->SetViewportOverlayWidget( TSharedPtr<SWindow>(), PIEViewportOverlayWidget.ToSharedRef() );
	PlayClient->SetGameLayerManager(GameLayerManager);

	// Our viewport widget should start rendering the new viewport for the play in editor scene
	ViewportWidget->SetViewportInterface( ActiveViewport.ToSharedRef() );

	// Let the viewport client know what viewport it is associated with
	PlayClient->Viewport = ActiveViewport.Get();

	// Register the new viewport widget with Slate for viewport specific message routing.
	FSlateApplication::Get().RegisterGameViewport( ViewportWidget.ToSharedRef() ); 

	// Kick off a quick transition effect (border graphics)
	ViewTransitionType = EViewTransition::StartingPlayInEditor;
	ViewTransitionAnim = FCurveSequence( 0.0f, 1.5f, ECurveEaseFunction::CubicOut );
	bViewTransitionAnimPending = true;
	GEditor->PlayEditorSound( TEXT( "/Engine/EditorSounds/GamePreview/StartPlayInEditor_Cue.StartPlayInEditor_Cue" ) );

	bPIEHasFocus = ActiveViewport->HasMouseCapture();

	ULevelEditorPlaySettings const* EditorPlayInSettings = GetDefault<ULevelEditorPlaySettings>();
	check(EditorPlayInSettings);

	if(EditorPlayInSettings->ShowMouseControlLabel)
	{
		ELabelAnchorMode AnchorMode = EditorPlayInSettings->MouseControlLabelPosition.GetValue();

		ShowMouseCaptureLabel(AnchorMode);
	}

	GEngine->BroadcastLevelActorListChanged();
}

EVisibility SLevelViewport::GetMouseCaptureLabelVisibility() const
{
	if (GEditor->PlayWorld)
	{
		// Show the label if the local player's PC isn't set to show the cursor
		auto const TargetPlayer = GEngine->GetLocalPlayerFromControllerId(GEditor->PlayWorld, 0);
		if (TargetPlayer && TargetPlayer->PlayerController && !TargetPlayer->PlayerController->bShowMouseCursor)
		{
			return EVisibility::HitTestInvisible;
		}
	}

	return EVisibility::Collapsed;
}

FLinearColor SLevelViewport::GetMouseCaptureLabelColorAndOpacity() const
{
	static const FName DefaultForegroundName("DefaultForeground");

	FSlateColor SlateColor = FEditorStyle::GetSlateColor(DefaultForegroundName);
	FLinearColor Col = SlateColor.IsColorSpecified() ? SlateColor.GetSpecifiedColor() : FLinearColor::White; 

	float Alpha = 0.0f;
	
	if(ViewTransitionAnim.IsPlaying() && ViewTransitionType == EViewTransition::StartingPlayInEditor)
	{
		Alpha = ViewTransitionAnim.GetLerp();
	}
	else if(PIEOverlayAnim.IsPlaying())
	{
		Alpha = 1.0f - PIEOverlayAnim.GetLerp();
	}
	
	return Col.CopyWithNewOpacity(Alpha);
}

FText SLevelViewport::GetMouseCaptureLabelText() const
{
	if(ActiveViewport->HasMouseCapture())
	{
		// Only need to fetch the exec binding once since it can't change
		// but better than hard coding to the current binding.
		static FInputChord Chord(EKeys::F1, EModifierKey::Shift);
		static bool bInitedChord = false;
		if(!bInitedChord)
		{
			ULocalPlayer* const TargetPlayer = GEngine->GetLocalPlayerFromControllerId(GetWorld(), 0);
			if (TargetPlayer && TargetPlayer->PlayerController && TargetPlayer->PlayerController->PlayerInput)
			{
				FKeyBind Binding = TargetPlayer->PlayerController->PlayerInput->GetExecBind(TEXT("ShowMouseCursor"));
				Chord = FInputChord(Binding.Key, EModifierKey::FromBools(Binding.Control, Binding.Alt, Binding.Shift, Binding.Cmd));
				bInitedChord = true;
			}
		}

		FFormatNamedArguments Args;
		Args.Add( TEXT("InputText"), Chord.GetInputText() );
		return FText::Format( LOCTEXT("ShowMouseCursorLabel", "{InputText} for Mouse Cursor"), Args );
	}
	else
	{
		return LOCTEXT("GameMouseControlLabel", "Click for Mouse Control");
	}
}

void SLevelViewport::ShowMouseCaptureLabel(ELabelAnchorMode AnchorMode)
{
	static_assert((EVerticalAlignment)((ELabelAnchorMode::LabelAnchorMode_TopLeft / 3) + 1) == EVerticalAlignment::VAlign_Top && (EHorizontalAlignment)((ELabelAnchorMode::LabelAnchorMode_TopLeft % 3) + 1) == EHorizontalAlignment::HAlign_Left, "Alignment from ELabelAnchorMode error.");
	static_assert((EVerticalAlignment)((ELabelAnchorMode::LabelAnchorMode_TopCenter / 3) + 1) == EVerticalAlignment::VAlign_Top && (EHorizontalAlignment)((ELabelAnchorMode::LabelAnchorMode_TopCenter % 3) + 1) == EHorizontalAlignment::HAlign_Center, "Alignment from ELabelAnchorMode error.");
	static_assert((EVerticalAlignment)((ELabelAnchorMode::LabelAnchorMode_TopRight / 3) + 1) == EVerticalAlignment::VAlign_Top && (EHorizontalAlignment)((ELabelAnchorMode::LabelAnchorMode_TopRight % 3) + 1) == EHorizontalAlignment::HAlign_Right, "Alignment from ELabelAnchorMode error.");
	
	static_assert((EVerticalAlignment)((ELabelAnchorMode::LabelAnchorMode_CenterLeft / 3) + 1) == EVerticalAlignment::VAlign_Center && (EHorizontalAlignment)((ELabelAnchorMode::LabelAnchorMode_CenterLeft % 3) + 1) == EHorizontalAlignment::HAlign_Left, "Alignment from ELabelAnchorMode error.");
	static_assert((EVerticalAlignment)((ELabelAnchorMode::LabelAnchorMode_Centered / 3) + 1) == EVerticalAlignment::VAlign_Center && (EHorizontalAlignment)((ELabelAnchorMode::LabelAnchorMode_Centered % 3) + 1) == EHorizontalAlignment::HAlign_Center, "Alignment from ELabelAnchorMode error.");
	static_assert((EVerticalAlignment)((ELabelAnchorMode::LabelAnchorMode_CenterRight / 3) + 1) == EVerticalAlignment::VAlign_Center && (EHorizontalAlignment)((ELabelAnchorMode::LabelAnchorMode_CenterRight % 3) + 1) == EHorizontalAlignment::HAlign_Right, "Alignment from ELabelAnchorMode error.");
	
	static_assert((EVerticalAlignment)((ELabelAnchorMode::LabelAnchorMode_BottomLeft / 3) + 1) == EVerticalAlignment::VAlign_Bottom && (EHorizontalAlignment)((ELabelAnchorMode::LabelAnchorMode_BottomLeft % 3) + 1) == EHorizontalAlignment::HAlign_Left, "Alignment from ELabelAnchorMode error.");
	static_assert((EVerticalAlignment)((ELabelAnchorMode::LabelAnchorMode_BottomCenter / 3) + 1) == EVerticalAlignment::VAlign_Bottom && (EHorizontalAlignment)((ELabelAnchorMode::LabelAnchorMode_BottomCenter % 3) + 1) == EHorizontalAlignment::HAlign_Center, "Alignment from ELabelAnchorMode error.");
	static_assert((EVerticalAlignment)((ELabelAnchorMode::LabelAnchorMode_BottomRight / 3) + 1) == EVerticalAlignment::VAlign_Bottom && (EHorizontalAlignment)((ELabelAnchorMode::LabelAnchorMode_BottomRight % 3) + 1) == EHorizontalAlignment::HAlign_Right, "Alignment from ELabelAnchorMode error.");
	
	EVerticalAlignment VAlign = (EVerticalAlignment)((AnchorMode/3)+1);
	EHorizontalAlignment HAlign = (EHorizontalAlignment)((AnchorMode%3)+1);
	
	SOverlay::FOverlaySlot& Slot = ViewportOverlay->AddSlot();
	PIEOverlaySlotIndex = Slot.ZOrder;

	Slot.HAlign(HAlign)
	.VAlign(VAlign)
	[
		SNew( SBorder )
		.BorderImage( FEditorStyle::GetBrush("NoBorder") )
		.Visibility(this, &SLevelViewport::GetMouseCaptureLabelVisibility)
		.ColorAndOpacity( this, &SLevelViewport::GetMouseCaptureLabelColorAndOpacity )
		.ForegroundColor( FLinearColor::White )
		.Padding(15.0f)
		[
			SNew( SButton )
			.ButtonStyle( FEditorStyle::Get(), "EditorViewportToolBar.MenuButton" )
			.IsFocusable(false)
			.ButtonColorAndOpacity( FSlateColor(FLinearColor::Black) )
			.ForegroundColor( FLinearColor::White )
			[
				SNew( SHorizontalBox )
				+ SHorizontalBox::Slot()
				.MaxWidth(32.f)
				.VAlign(VAlign_Center)
				.Padding(0.0f, 2.0f, 2.0f, 2.0f)
				[
					SNew( SVerticalBox )
					+ SVerticalBox::Slot()
					.MaxHeight(16.f)
					[
						SNew(SImage)
						.Image(FEditorStyle::GetBrush("LevelViewport.CursorIcon"))
					]
				]
				+ SHorizontalBox::Slot()
				.AutoWidth()
				.VAlign(VAlign_Center)
				.HAlign(HAlign_Center)
				.Padding(2.0f, 2.0f)
				[
					SNew(STextBlock)
					.Text(this, &SLevelViewport::GetMouseCaptureLabelText)
					.Font( FSlateFontInfo( FPaths::EngineContentDir() / TEXT("Slate/Fonts/Roboto-Bold.ttf"), 9 ) )
					.ColorAndOpacity(FLinearColor::White)
				]
			]
		]
	];
}

void SLevelViewport::HideMouseCaptureLabel()
{
	ViewportOverlay->RemoveSlot(PIEOverlaySlotIndex);
	PIEOverlaySlotIndex = 0;
}

void SLevelViewport::ResetNewLevelViewFlags()
{
	ChangeExposureSetting(FEditorViewportCommands::AutoExposureRadioID);

	const bool bUseSavedDefaults = true;
	OnUseDefaultShowFlags(bUseSavedDefaults);
}

void SLevelViewport::EndPlayInEditorSession()
{
	check( HasPlayInEditorViewport() );

	FSlateApplication::Get().UnregisterGameViewport();

	check( InactiveViewport.IsValid() );

	if( IsPlayInEditorViewportActive() )
	{
		ActiveViewport->OnPlayWorldViewportSwapped(*InactiveViewport);

		// Play in editor viewport was active, swap back to our level editor viewport
		ActiveViewport->SetViewportClient( NULL );

		// We should be the only thing holding on to viewports
		check( ActiveViewport.IsUnique() );

		ActiveViewport = InactiveViewport;
	
		// Ensure our active viewport is for level editing
		check( ActiveViewport->GetClient() == LevelViewportClient.Get() );

		// Restore camera settings that may be adversely affected by PIE
		LevelViewportClient->RestoreCameraFromPIE();
		RedrawViewport(true);
	}
	else
	{
		InactiveViewport->SetViewportClient( NULL );
	}

	// Reset the inactive viewport
	InactiveViewport.Reset();

	// Viewport widget should begin drawing the editor viewport
	ViewportWidget->SetViewportInterface( ActiveViewport.ToSharedRef() );
	ViewportWidget->SetContent( InactiveViewportWidgetEditorContent );

	// No longer need to store the content 
	InactiveViewportWidgetEditorContent.Reset();

	if(PIEOverlaySlotIndex)
	{
		HideMouseCaptureLabel();
	}

	// Kick off a quick transition effect (border graphics)
	ViewTransitionType = EViewTransition::ReturningToEditor;
	ViewTransitionAnim = FCurveSequence( 0.0f, 1.5f, ECurveEaseFunction::CubicOut );
	bViewTransitionAnimPending = true;
	GEditor->PlayEditorSound( TEXT( "/Engine/EditorSounds/GamePreview/EndPlayInEditor_Cue.EndPlayInEditor_Cue" ) );

	GEngine->BroadcastLevelActorListChanged();
}

void SLevelViewport::SwapViewportsForSimulateInEditor()
{
	// Ensure our active viewport was the play in editor viewport
	check( IsPlayInEditorViewportActive() );
	
	// Remove the mouse control label - not relevant for SIE
	if(PIEOverlaySlotIndex)
	{
		HideMouseCaptureLabel();
	}

	// Unregister the game viewport with slate which will release mouse capture and lock
	FSlateApplication::Get().UnregisterGameViewport();

	// Swap between the active and inactive viewport
	TSharedPtr<FSceneViewport> TempViewport = ActiveViewport;
	ActiveViewport = InactiveViewport;
	InactiveViewport = TempViewport;

	ViewportWidget->SetContent( InactiveViewportWidgetEditorContent );

	// Resize the viewport to be the same size the previously active viewport
	// When starting in immersive mode its possible that the viewport has not been resized yet
	ActiveViewport->OnPlayWorldViewportSwapped( *InactiveViewport );
	
	ViewportWidget->SetViewportInterface( ActiveViewport.ToSharedRef() );

	// Kick off a quick transition effect (border graphics)
	ViewTransitionType = EViewTransition::StartingSimulate;
	ViewTransitionAnim = FCurveSequence( 0.0f, 1.5f, ECurveEaseFunction::CubicOut );
	bViewTransitionAnimPending = true;
	GEditor->PlayEditorSound( TEXT( "/Engine/EditorSounds/GamePreview/PossessPlayer_Cue.PossessPlayer_Cue" ) );
}


void SLevelViewport::SwapViewportsForPlayInEditor()
{
	// Ensure our inactive viewport was the play in editor viewport
	check( !IsPlayInEditorViewportActive() && HasPlayInEditorViewport() );
	
	// Put the mouse control label up again.
	ULevelEditorPlaySettings const* EditorPlayInSettings = GetDefault<ULevelEditorPlaySettings>();
	check(EditorPlayInSettings);
	
	if(EditorPlayInSettings->ShowMouseControlLabel)
	{
		ELabelAnchorMode AnchorMode = EditorPlayInSettings->MouseControlLabelPosition.GetValue();
		
		ShowMouseCaptureLabel(AnchorMode);
	}

	// Swap between the active and inactive viewport
	TSharedPtr<FSceneViewport> TempViewport = ActiveViewport;
	ActiveViewport = InactiveViewport;
	InactiveViewport = TempViewport;

	// Resize the viewport to be the same size the previously active viewport
	// When starting in immersive mode its possible that the viewport has not been resized yet
	ActiveViewport->OnPlayWorldViewportSwapped( *InactiveViewport );

	InactiveViewportWidgetEditorContent = ViewportWidget->GetContent();
	ViewportWidget->SetViewportInterface( ActiveViewport.ToSharedRef() );

	// Register the game viewport with slate which will capture the mouse and lock it to the viewport
	FSlateApplication::Get().RegisterGameViewport( ViewportWidget.ToSharedRef() );

	// Kick off a quick transition effect (border graphics)
	ViewTransitionType = EViewTransition::StartingPlayInEditor;
	ViewTransitionAnim = FCurveSequence( 0.0f, 1.5f, ECurveEaseFunction::CubicOut );
	bViewTransitionAnimPending = true;
	GEditor->PlayEditorSound( TEXT( "/Engine/EditorSounds/GamePreview/EjectFromPlayer_Cue.EjectFromPlayer_Cue" ) );
}


void SLevelViewport::OnSimulateSessionStarted()
{
	// Kick off a quick transition effect (border graphics)
	ViewTransitionType = EViewTransition::StartingSimulate;
	ViewTransitionAnim = FCurveSequence( 0.0f, 1.5f, ECurveEaseFunction::CubicOut );
	bViewTransitionAnimPending = true;
	GEditor->PlayEditorSound( TEXT( "/Engine/EditorSounds/GamePreview/StartSimulate_Cue.StartSimulate_Cue" ) );
	 
	// Make sure the viewport's hit proxies are invalidated.  If not done, clicking in the viewport could select an editor world actor
	ActiveViewport->InvalidateHitProxy();
}


void SLevelViewport::OnSimulateSessionFinished()
{
	// Kick off a quick transition effect (border graphics)
	ViewTransitionType = EViewTransition::ReturningToEditor;
	ViewTransitionAnim = FCurveSequence( 0.0f, 1.5f, ECurveEaseFunction::CubicOut );
	bViewTransitionAnimPending = true;
	GEditor->PlayEditorSound( TEXT( "/Engine/EditorSounds/GamePreview/EndSimulate_Cue.EndSimulate_Cue" ) );

	// Make sure the viewport's hit proxies are invalidated.  If not done, clicking in the viewport could select a pie world actor
	ActiveViewport->InvalidateHitProxy();
}

EVisibility SLevelViewport::GetLockedIconVisibility() const
{
	return IsAnyActorLocked() ? EVisibility::Visible : EVisibility::Collapsed;
}

FText SLevelViewport::GetLockedIconToolTip() const
{
	FText ToolTip;
	if (IsAnyActorLocked())
	{
		ToolTip = FText::Format( LOCTEXT("ActorLockedIcon_ToolTip", "Viewport Locked to {0}"), FText::FromString( LevelViewportClient->GetActiveActorLock().Get()->GetActorLabel() ) );
	}

	return ToolTip;
}

UWorld* SLevelViewport::GetWorld() const
{
	return ParentLevelEditor.IsValid() ? ParentLevelEditor.Pin()->GetWorld() : NULL;
}

void SLevelViewport::RemoveActorPreview( int32 PreviewIndex )
{
	// Remove widget from viewport overlay
	ActorPreviewHorizontalBox->RemoveSlot( ActorPreviews[PreviewIndex].PreviewWidget.ToSharedRef() );

	// Clean up our level viewport client
	if( ActorPreviews[PreviewIndex].LevelViewportClient.IsValid() )
	{
		ActorPreviews[PreviewIndex].LevelViewportClient->Viewport = NULL;
	}

	// Remove from our list of actor previews.  This will destroy our level viewport client and viewport widget.
	ActorPreviews.RemoveAt( PreviewIndex );
}

void SLevelViewport::AddOverlayWidget(TSharedRef<SWidget> OverlaidWidget)
{
	ViewportOverlay->AddSlot()
	[
		OverlaidWidget
	];
}

void SLevelViewport::RemoveOverlayWidget(TSharedRef<SWidget> OverlaidWidget)
{
	ViewportOverlay->RemoveSlot(OverlaidWidget);
}

bool SLevelViewport::CanProduceActionForCommand(const TSharedRef<const FUICommandInfo>& Command) const
{

	FLevelEditorModule& LevelEditorModule = FModuleManager::GetModuleChecked<FLevelEditorModule>( LevelEditorName );
	TSharedPtr<ILevelViewport> ActiveLevelViewport = LevelEditorModule.GetFirstActiveViewport();
	if ( ActiveLevelViewport.IsValid() )
	{
		return ActiveLevelViewport == SharedThis(this);
	}

	return false;
}

void SLevelViewport::LockActorInternal(AActor* NewActorToLock)
{
	if (NewActorToLock != NULL)
	{
		LevelViewportClient->SetActorLock(NewActorToLock);
		if (LevelViewportClient->IsPerspective() && LevelViewportClient->GetActiveActorLock().IsValid())
		{
			LevelViewportClient->MoveCameraToLockedActor();
		}
	}

	// Make sure the inset preview is closed if we are locking a camera that was already part of the selection set and thus being previewed.
	OnPreviewSelectedCamerasChange();
}

bool SLevelViewport::GetCameraInformationFromActor(AActor* Actor, FMinimalViewInfo& out_CameraInfo)
{
	// @todo camerapip: Could support actors other than cameras too!  (Character views?)
	//@TODO: CAMERA: Support richer camera interactions in SIE; this may shake out naturally if everything uses camera components though
	if (UCameraComponent* CameraComponent = Actor->FindComponentByClass<UCameraComponent>())
	{
		CameraComponent->GetCameraView(0.0f, out_CameraInfo);
		return true;
	}

	return false;
}

bool SLevelViewport::CanGetCameraInformationFromActor(AActor* Actor)
{
	FMinimalViewInfo CameraInfo;

	return GetCameraInformationFromActor(Actor, /*out*/ CameraInfo);
}

void SLevelViewport::TakeHighResScreenShot()
{
	if( LevelViewportClient.IsValid() )
	{
		LevelViewportClient->TakeHighResScreenShot();
	}
}

void SLevelViewport::OnFloatingButtonClicked()
{
	// if one of the viewports floating buttons has been clicked, update the global viewport ptr
	LevelViewportClient->SetLastKeyViewport();
}

#undef LOCTEXT_NAMESPACE