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  3. ULevelStreaming

ULevelStreaming

Abstract base class of container object encapsulating data required for streaming and providing interface for when a level should be streamed in and out of memory.

Unreal Engine C++ API Reference > Runtime > Engine > Engine

Inheritance Hierarchy

References

   
Module Engine
Header /Engine/Source/Runtime/Engine/Classes/Engine/LevelStreaming.h
Include #include "Engine/LevelStreaming.h"

Syntax

class ULevelStreaming : public UObject

Remarks

Abstract base class of container object encapsulating data required for streaming and providing interface for when a level should be streamed in and out of memory.

Variables

  Type Name Description
Public variable bool bClientOnlyVisible Applied to LoadedLevel
Public variable uint8: 1 bDisableDistanceStreaming Whether this level streaming object should be ignored by world composition distance streaming, so streaming state can be controlled by other systems (ex: in blueprints)
Public variable uint8: 1 bDrawOnLevelStatusMap If true, will be drawn on the 'level streaming status' map (STAT LEVELMAP console command)
Public variable uint8: 1 bGarbageCollectionClusteringEnabled If true, allows garbage collection clustering for the level.
Public variable uint8: 1 bIsStatic Whether this level only contains static actors that aren't affected by gameplay or replication.
Public variable uint8: 1 bLocked Whether this level is locked; that is, its actors are read-only.
Protected variable uint8: 1 bShouldBeLoaded Whether the level should be loaded
Public variable uint8: 1 bShouldBlockOnLoad Whether we want to force a blocking load
Public variable uint8: 1 bShouldBlockOnUnload Whether we want to force a blocking unload
Protected variable uint8: 1 bSkipClientUseMakingInvisibleTransactionRequest Whether the streaming level can safely skip making invisible transaction request from the client to the server
Protected variable uint8: 1 bSkipClientUseMakingVisibleTransactionRequest Whether the streaming level can safely skip making visible transaction request from the client to the server
Public variable TArray< TObjectPtr< ALevelStreamingVolume > > EditorStreamingVolumes The level streaming volumes bound to this level.
Public variable ECurrentState FailedToLoad  
Public variable TArray< FString > Keywords List of keywords to filter on in the level browser
Public variable float LastVolumeUnloadRequestTime Time of last volume unload request. Used in preventing spurious unload requests.
Public variable FLinearColor LevelColor The level color used for visualization. (Show -> Advanced -> Level Coloration)
Public variable FTransform LevelTransform Transform applied to actors after loading.
Protected variable TObjectPtr< class ULevel > LoadedLevel Pointer to Level object if currently loaded/ streamed in.
Public variable ECurrentState LoadedNotVisible  
Public variable ECurrentState LoadedVisible  
Public variable ECurrentState Loading  
Public variable TArray< FName > LODPackageNames LOD versions of this level
Public variable TArray< FName > LODPackageNamesToLoad LOD package names on disk
Public variable ECurrentState MakingInvisible  
Public variable ECurrentState MakingVisible  
Public variable float MinTimeBetweenVolumeUnloadRequests Cooldown time in seconds between volume-based unload requests.
Public variable FLevelStreamingVisibilityStatus OnLevelHidden Called when level is no longer visible, may not be removed from world yet
Public variable FLevelStreamingLoadedStatus OnLevelLoaded Called when level is streamed in
Public variable FLevelStreamingVisibilityStatus OnLevelShown Called when level is added to the world and is visible
Public variable FLevelStreamingLoadedStatus OnLevelUnloaded Called when level is streamed out
Public variable FName PackageNameToLoad If this isn't Name_None, then we load from this package on disk to the new package named PackageName
Protected variable TObjectPtr< class ULevel > PendingUnloadLevel Pointer to a Level object that was previously active and was replaced with a new LoadedLevel (for LOD switching)
Protected variable int32 StreamingPriority The relative priority of considering the streaming level.
Public variable ECurrentState Unloaded  
Protected variable TSoftObjectPtr< UWorld > WorldAsset The reference to the world containing the level to load

Constructors

  Type Name Description
Public function  

ULevelStreaming ( const FObjectInitializer& ObjectInitializer
)

  

Functions

  Type Name Description
Public function void  
Public function void

BeginClientNetVisibilityRequest ( bool bInShouldBeVisible
)

 Begin a client instigated NetVisibility request
Public function Static void

BroadcastLevelLoadedStatus ( UWorld* PersistentWorld,
FName LevelPackageName,
bool bLoaded
)

 Traverses all streaming level objects in the persistent world and in all inner worlds and calls appropriate delegate for streaming objects that refer specified level
Public function Static void

BroadcastLevelVisibleStatus ( UWorld* PersistentWorld,
FName LevelPackageName,
bool bVisible
)

 Traverses all streaming level objects in the persistent world and in all inner worlds and calls appropriate delegate for streaming objects that refer specified level
Protected function bool Returns whether the streaming level can make invisible (can call RemoveFromWorld).
Protected function bool Returns whether the streaming level can make visible (can call AddToWorld).
Public function Virtual Const bool Returns whether level status can be replicated from the server to the client
Public function void Sets the LoadedLevel value to NULL
Public function ULevelStreaming *

CreateInstance ( const FString& UniqueInstanceName
)

 Creates a new instance of this streaming level with a provided unique instance name
Public function Static void

DebugDrawLegend ( const UWorld* World,
UCanvas* Canvas,
const FVector2D& Offset
)

 Utility that draws a legend of level streaming status
Public function Static bool Whether client should be using making invisible transaction requests to the server (default value).
Public function Static bool Whether client should be using making visible transaction requests to the server (default value).
Public function Static PRAGMA_DISABLE_DEPRECATION_WARNINGS const TCHAR *

EnumToString ( ECurrentState InCurrentState
)

  
Public function Static ULevelStreaming *

FindStreamingLevel ( const ULevel* Level
)

  
Public function Const const FName & Get the folder path for this level for use in the world browser. Only available in editor builds
Public function Virtual Const TOptional< FFolder::FRootObject >  
Public function Const bool Returns if the streaming level has requested to be unloaded and removed.
Public function Const int32 Returns the world composition level LOD index.
Public function ALevelScriptActor * Returns the Level Script Actor of the level if the level is loaded and valid
Public function Const ELevelStreamingState  
Public function Const EStreamingStatus Used for debugging Level's status
Public function Static FColor

GetLevelStreamingStatusColor ( EStreamingStatus Status
)

 Utility that gets a color for a particular level status
Public function Static const TCHAR *

GetLevelStreamingStatusDisplayName ( EStreamingStatus Status
)

 Utility that returns a string for a streaming level status
Public function Const ULevel * Gets a pointer to the LoadedLevel value
Protected function Const FName  
Public function Const int32 Sets the relative priority of considering the streaming level.
Public function Const bool Returns the value of bShouldBeVisible.
Public function Const bool Returns if the streaming level should be visible in the editor.
Public function FBox Get a bounding box around the streaming volumes associated with this LevelStreaming object
Public function Virtual Const UWorld * Returns the UWorld that triggered the streaming of this streaming level.
Public function Virtual Const UWorld *  
Public function Const const TSoftObjectPtr< UWorld > & Returns a constant reference to the world asset this streaming level object references
Public function Virtual Const FName Gets the package name for the world asset referred to by this level streaming as an FName
Public function Const FString Gets the package name for the world asset referred to by this level streaming
Public function Virtual Const const IWorldPartitionCell *  
Public function Const bool Returns whether the streaming level has loaded a level.
Public function Const bool Returns whether the streaming level is in the loading state.
Public function Const bool Returns whether streaming level is loaded
Public function Const bool Returns whether streaming level is visible
Public function Const bool Returns whether level has streaming state change pending
Public function Virtual Const bool Returns if the streaming level can be modified by user
Public function Const bool Returns false if the level package associated to that streaming level is invalid.
Public function Const bool

IsWaitingForNetVisibilityTransactionAck ( ENetLevelVisibilityRequest InRequestType
)

 Check if we are waiting for a making visible or invisible streaming transaction
Protected function Virtual void Called by SetLoadedLevel
Protected function void  
Protected function void  
Protected function void

PrepareLoadedLevel ( ULevel* InLevel,
UPackage* InLevelPackage,
int32 InPIEInstanceID
)

 Sets loaded level, fixups for PIE, notifies level is loaded, apply necessary modifications on level once loaded.
Public function Static void

RemoveLevelAnnotation ( const ULevel* Level
)

  
Public function void After a sub level is reloaded in the editor the cache state needs to be refreshed.
Public function void Remove duplicates in EditorStreamingVolumes list
Public function void

RenameForPIE ( int PIEInstanceID,
bool bKeepWorldAssetName
)

 Rename package name to PIE appropriate name
Protected function Virtual bool

RequestLevel ( UWorld* PersistentWorld,
bool bAllowLevelLoadRequests,
EReqLevelBlock BlockPolicy
)

 Try to find loaded level in memory, issue a loading request otherwise
Protected function Virtual bool

RequestVisibilityChange ( bool bVisible
)

 Prepare the transition to the new state.
Protected function void

SetCurrentState ( ELevelStreamingState NewState
)

 Updates the current state of the streaming level and notifies any observers.
Public function void

SetFolderPath ( const FName& InFolderPath
)

 Sets the folder path for this level in the world browser. Only available in editor builds
Public function void

SetIsRequestingUnloadAndRemoval ( bool bInIsRequestingUnloadAndRemoval
)

 Sets if the streaming level should be unloaded and removed.
Public function void

SetLevelLODIndex ( int32 LODIndex
)

 Sets the world composition level LOD index and marks the streaming level as requiring consideration.
Protected function Virtual void

SetLoadedLevel ( ULevel* Level
)

 Sets the value of LoadedLevel
Public function void

SetPriority ( int32 NewPriority
)

 Sets the relative priority of considering the streaming level.
Public function Virtual void

SetShouldBeLoaded ( bool bInShouldBeLoaded
)

 Virtual that can be overridden to change whether a streaming level should be loaded.
Public function void

SetShouldBeVisible ( bool bInShouldBeVisible
)

 Sets the should be visible flag and marks the streaming level as requiring consideration.
Public function void

SetShouldBeVisibleInEditor ( bool bInShouldBeVisibleInEditor
)

 Sets if the streaming level should be visible in the editor.
Public function Virtual void

SetWorldAsset ( const TSoftObjectPtr< UWorld >& NewWorldAsset
)

 Setter for WorldAsset.
Public function void

SetWorldAssetByPackageName ( FName InPackageName
)

 Sets the world asset based on the package name assuming it contains a world of the same name.
Public function Virtual Const bool  
Public function Virtual Const bool Return whether this level should be present in memory which in turn tells the streaming code to stream it in.
Public function Virtual Const bool Return whether this level should be visible/ associated with the world if it is loaded.
Public function Virtual Const bool  
Public function Virtual Const bool Returns whether level should start to render only when it will be fully added to the world or not.
Public function Static bool If true level streaming can reuse an unloaded level that wasn't GC'd yet.
Public function Static bool If true server will wait for client acknowledgment before making treating streaming levels as visible for the client
Public function Virtual Const bool Returns if the streaming level is visible in LevelCollectionModel
Public function void

UpdateNetVisibilityTransactionState ( bool bInShouldBeVisible,
FNetLevelVisibilityTransactionId TransactionId
)

 Set the current state of the current visibility/streaming transaction

Overridden from UObject

  Type Name Description
Public function Virtual void

PostEditChangeProperty ( FPropertyChangedEvent& PropertyChangedEvent
)

 Called when a property on this object has been modified externally
Public function Virtual void Override Pre/PostEditUndo functions to handle editor transform
Public function Virtual void Do any object-specific cleanup required immediately after loading an object.
Public function Virtual void Handles reading, writing, and reference collecting using FArchive.

Classes

  Type Name Description
Public struct FLevelAnnotation Annotation for fast inverse lookup.  
Public struct FPackageNameMatcher Matcher for searching streaming levels by PackageName  

Enums

  Type Name Description
Public enum EReqLevelBlock    

Constants

Name Description
LevelAnnotations  

Deprecated Variables

  Type Name Description
Public variable ECurrentState: uint8 { Removed = (uint8)ELevelStreamingState::Removed pad0 ULevelStreaming::ECurrentState has been replaced by ELevelStreamingState
Public variable FColor DrawColor_DEPRECATED Deprecated level color used for visualization.
Public variable FName PackageName_DEPRECATED Deprecated name of the package containing the level to load.

Deprecated Functions

  Type Name Description
Public function Const PRAGMA_DISABLE_DEPRECATION_WARNINGSECurrentState ULevelStreaming::ECurrentState has been replaced by ELevelStreamingState. Use GetLevelStreamingState instead.

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