标签：UPROPERTY World PIE FWorldContext WorldContext UWorld UE world
1 类图
前面对World和Level的关系和源码进行了简单分析，这里介绍WorldContext，同样首先给出类图。
2 WorldContext
在上一篇文章中对World概念及类型做出了简单的分析。那么World不止有一个，类型也不止有一个，UE中是使用什么对World进行管理呢？就是WorldContext。
首先卡看WorldContext代码：
/** FWorldContext
* A context for dealing with UWorlds at the engine level. As the engine brings up and destroys world, we need a way to keep straight
* what world belongs to what.
*
* WorldContexts can be thought of as a track. By default we have 1 track that we load and unload levels on. Adding a second context is adding
* a second track; another track of progression for worlds to live on.
*
* For the GameEngine, there will be one WorldContext until we decide to support multiple simultaneous worlds.
* For the EditorEngine, there may be one WorldContext for the EditorWorld and one for the PIE World.
*
* FWorldContext provides both a way to manage 'the current PIE UWorld*' as well as state that goes along with connecting/travelling to
* new worlds.
*
* FWorldContext should remain internal to the UEngine classes. Outside code should not keep pointers or try to manage FWorldContexts directly.
* Outside code can still deal with UWorld*, and pass UWorld*s into Engine level functions. The Engine code can look up the relevant context
* for a given UWorld*.
*
* For convenience, FWorldContext can maintain outside pointers to UWorld*s. For example, PIE can tie UWorld* UEditorEngine::PlayWorld to the PIE
* world context. If the PIE UWorld changes, the UEditorEngine::PlayWorld pointer will be automatically updated. This is done with AddRef() and
* SetCurrentWorld().
*
*/
USTRUCT()
struct FWorldContext
{
GENERATED_USTRUCT_BODY()
/**************************************************************/
TEnumAsByte<EWorldType::Type> WorldType;
FSeamlessTravelHandler SeamlessTravelHandler;
FName ContextHandle;
/** URL to travel to for pending client connect */
FString TravelURL;
/** TravelType for pending client connects */
uint8 TravelType;
/** URL the last time we traveled */
UPROPERTY()
struct FURL LastURL;
/** last server we connected to (for "reconnect" command) */
UPROPERTY()
struct FURL LastRemoteURL;
UPROPERTY()
UPendingNetGame * PendingNetGame;
/** A list of tag/array pairs that is used at LoadMap time to fully load packages that may be needed for the map/game with DLC, but we can't use DynamicLoadObject to load from the packages */
UPROPERTY()
TArray<struct FFullyLoadedPackagesInfo> PackagesToFullyLoad;
/**
* Array of package/ level names that need to be loaded for the pending map change. First level in that array is
* going to be made a fake persistent one by using ULevelStreamingPersistent.
*/
TArray<FName> LevelsToLoadForPendingMapChange;
/** Array of already loaded levels. The ordering is arbitrary and depends on what is already loaded and such. */
UPROPERTY()
TArray<class ULevel*> LoadedLevelsForPendingMapChange;
/** Human readable error string for any failure during a map change request. Empty if there were no failures. */
FString PendingMapChangeFailureDescription;
/** If true, commit map change the next frame. */
uint32 bShouldCommitPendingMapChange:1;
/** Handles to object references; used by the engine to e.g. the prevent objects from being garbage collected. */
UPROPERTY()
TArray<class UObjectReferencer*> ObjectReferencers;
UPROPERTY()
TArray<struct FLevelStreamingStatus> PendingLevelStreamingStatusUpdates;
UPROPERTY()
class UGameViewportClient* GameViewport;
UPROPERTY()
class UGameInstance* OwningGameInstance;
/** A list of active net drivers */
UPROPERTY(transient)
TArray<FNamedNetDriver> ActiveNetDrivers;
/** The PIE instance of this world, -1 is default */
int32 PIEInstance;
/** The Prefix in front of PIE level names, empty is default */
FString PIEPrefix;
/** The feature level that PIE world should use */
ERHIFeatureLevel::Type PIEWorldFeatureLevel;
/** Is this running as a dedicated server */
bool RunAsDedicated;
/** Is this world context waiting for an online login to complete (for PIE) */
bool bWaitingOnOnlineSubsystem;
/** Handle to this world context's audio device.*/
uint32 AudioDeviceID;
/** Custom description to be display in blueprint debugger UI */
FString CustomDescription;
// If > 0, tick this world at a fixed rate in PIE
float PIEFixedTickSeconds = 0.f;
float PIEAccumulatedTickSeconds = 0.f;
/**************************************************************/
/** Outside pointers to CurrentWorld that should be kept in sync if current world changes */
TArray<UWorld**> ExternalReferences;
/** Adds an external reference */
void AddRef(UWorld*& WorldPtr)
{
WorldPtr = ThisCurrentWorld;
ExternalReferences.AddUnique(&WorldPtr);
}
/** Removes an external reference */
void RemoveRef(UWorld*& WorldPtr)
{
ExternalReferences.Remove(&WorldPtr);
WorldPtr = nullptr;
}
/** Set CurrentWorld and update external reference pointers to reflect this*/
ENGINE_API void SetCurrentWorld(UWorld *World);
/** Collect FWorldContext references for garbage collection */
void AddReferencedObjects(FReferenceCollector& Collector, const UObject* ReferencingObject);
FORCEINLINE UWorld* World() const
{
return ThisCurrentWorld;
}
FWorldContext()
: WorldType(EWorldType::None)
, ContextHandle(NAME_None)
, TravelURL()
, TravelType(0)
, PendingNetGame(nullptr)
, bShouldCommitPendingMapChange(0)
, GameViewport(nullptr)
, OwningGameInstance(nullptr)
, PIEInstance(INDEX_NONE)
, PIEWorldFeatureLevel(ERHIFeatureLevel::Num)
, RunAsDedicated(false)
, bWaitingOnOnlineSubsystem(false)
, AudioDeviceID(INDEX_NONE)
, ThisCurrentWorld(nullptr)
{ }
private:
UWorld* ThisCurrentWorld;
};
标签：UPROPERTY,World,PIE,FWorldContext,WorldContext,UWorld,UE,world 来源： https://www.cnblogs.com/hxhspace/p/16139977.html
本站声明： 1. iCode9 技术分享网（下文简称本站）提供的所有内容，仅供技术学习、探讨和分享； 2. 关于本站的所有留言、评论、转载及引用，纯属内容发起人的个人观点，与本站观点和立场无关； 3. 关于本站的所有言论和文字，纯属内容发起人的个人观点，与本站观点和立场无关； 4. 本站文章均是网友提供，不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属；如您发现该文章侵犯了您的权益，可联系我们第一时间进行删除； 5. 本站为非盈利性的个人网站，所有内容不会用来进行牟利，也不会利用任何形式的广告来间接获益，纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。