LyraStarterGame_5.6 Experience系统加载流程详细实现-程序员充电站

1. 加载流程概述

Lyra的Experience系统采用异步加载模式，确保游戏在加载过程中保持响应性。完整的加载流程包含以下状态转换：

Unloaded → Loading → LoadingGameFeatures → ExecutingActions → Loaded

2. 详细流程实现

2.1 设置当前经验

voidULyraExperienceManagerComponent::SetCurrentExperience(FPrimaryAssetId ExperienceId){ULyraAssetManager&AssetManager=ULyraAssetManager::Get();FSoftObjectPath AssetPath=AssetManager.GetPrimaryAssetPath(ExperienceId);TSubclassOf<ULyraExperienceDefinition>AssetClass=Cast<UClass>(AssetPath.TryLoad());check(AssetClass);constULyraExperienceDefinition*Experience=GetDefault<ULyraExperienceDefinition>(AssetClass);check(Experience!=nullptr);check(CurrentExperience==nullptr);CurrentExperience=Experience;StartExperienceLoad();}

关键实现点：

通过ULyraAssetManager获取经验资源路径
尝试加载资源类并转换为ULyraExperienceDefinition类型
验证经验有效性并设置为当前经验
调用StartExperienceLoad()开始加载流程

2.2 开始经验加载

voidULyraExperienceManagerComponent::StartExperienceLoad(){check(CurrentExperience!=nullptr);check(LoadState==ELyraExperienceLoadState::Unloaded);UE_LOG(LogLyraExperience,Log,TEXT("EXPERIENCE: StartExperienceLoad(CurrentExperience = %s, %s)"),*CurrentExperience->GetPrimaryAssetId().ToString(),*GetClientServerContextString(this));LoadState=ELyraExperienceLoadState::Loading;ULyraAssetManager&AssetManager=ULyraAssetManager::Get();TSet<FPrimaryAssetId>BundleAssetList;TSet<FSoftObjectPath>RawAssetList;BundleAssetList.Add(CurrentExperience->GetPrimaryAssetId());for(constTObjectPtr<ULyraExperienceActionSet>&ActionSet:CurrentExperience->ActionSets){if(ActionSet!=nullptr){BundleAssetList.Add(ActionSet->GetPrimaryAssetId());}}TArray<FName>BundlesToLoad;BundlesToLoad.Add(FLyraBundles::Equipped);constENetMode OwnerNetMode=GetOwner()->GetNetMode();constboolbLoadClient=GIsEditor||(OwnerNetMode!=NM_DedicatedServer);constboolbLoadServer=GIsEditor||(OwnerNetMode!=NM_Client);if(bLoadClient)BundlesToLoad.Add(UGameFeaturesSubsystemSettings::LoadStateClient);if(bLoadServer)BundlesToLoad.Add(UGameFeaturesSubsystemSettings::LoadStateServer);TSharedPtr<FStreamableHandle>BundleLoadHandle=nullptr;if(BundleAssetList.Num()>0){BundleLoadHandle=AssetManager.ChangeBundleStateForPrimaryAssets(BundleAssetList.Array(),BundlesToLoad,{},false,FStreamableDelegate(),FStreamableManager::AsyncLoadHighPriority);}TSharedPtr<FStreamableHandle>RawLoadHandle=nullptr;if(RawAssetList.Num()>0){RawLoadHandle=AssetManager.LoadAssetList(RawAssetList.Array(),FStreamableDelegate(),FStreamableManager::AsyncLoadHighPriority,TEXT("StartExperienceLoad()"));}TSharedPtr<FStreamableHandle>Handle=nullptr;if(BundleLoadHandle.IsValid()&&RawLoadHandle.IsValid()){Handle=AssetManager.GetStreamableManager().CreateCombinedHandle({BundleLoadHandle,RawLoadHandle});}else{Handle=BundleLoadHandle.IsValid()?BundleLoadHandle:RawLoadHandle;}FStreamableDelegate OnAssetsLoadedDelegate=FStreamableDelegate::CreateUObject(this,&ThisClass::OnExperienceLoadComplete);if(!Handle.IsValid()||Handle->HasLoadCompleted()){FStreamableHandle::ExecuteDelegate(OnAssetsLoadedDelegate);}else{Handle->BindCompleteDelegate(OnAssetsLoadedDelegate);Handle->BindCancelDelegate(FStreamableDelegate::CreateLambda([OnAssetsLoadedDelegate](){OnAssetsLoadedDelegate.ExecuteIfBound();}));}TSet<FPrimaryAssetId>PreloadAssetList;if(PreloadAssetList.Num()>0){AssetManager.ChangeBundleStateForPrimaryAssets(PreloadAssetList.Array(),BundlesToLoad,{});}}

关键实现点：

验证当前经验有效性和加载状态
记录加载日志，包含经验ID和客户端/服务器上下文
转换状态为ELyraExperienceLoadState::Loading
构建要加载的资源列表，包括经验定义和相关动作集
根据网络模式（客户端/服务器/编辑器）确定要加载的资源包
使用FStreamableHandle进行异步资源加载
支持合并多个加载请求，提高效率
绑定资源加载完成回调
支持预加载额外资源（当前留空）

2.3 经验资源加载完成

voidULyraExperienceManagerComponent::OnExperienceLoadComplete(){check(LoadState==ELyraExperienceLoadState::Loading);check(CurrentExperience!=nullptr);UE_LOG(LogLyraExperience,Log,TEXT("EXPERIENCE: OnExperienceLoadComplete(CurrentExperience = %s, %s)"),*CurrentExperience->GetPrimaryAssetId().ToString(),*GetClientServerContextString(this));GameFeaturePluginURLs.Reset();autoCollectGameFeaturePluginURLs=[This=this](constUPrimaryDataAsset*Context,constTArray<FString>&FeaturePluginList){for(constFString&PluginName:FeaturePluginList){FString PluginURL;if(UGameFeaturesSubsystem::Get().GetPluginURLByName(PluginName,/*out*/PluginURL)){This->GameFeaturePluginURLs.AddUnique(PluginURL);}else{ensureMsgf(false,TEXT("OnExperienceLoadComplete failed to find plugin URL from PluginName %s for experience %s - fix data, ignoring for this run"),*PluginName,*Context->GetPrimaryAssetId().ToString());}}};CollectGameFeaturePluginURLs(CurrentExperience,CurrentExperience->GameFeaturesToEnable);for(constTObjectPtr<ULyraExperienceActionSet>&ActionSet:CurrentExperience->ActionSets){if(ActionSet!=nullptr){CollectGameFeaturePluginURLs(ActionSet,ActionSet->GameFeaturesToEnable);}}NumGameFeaturePluginsLoading=GameFeaturePluginURLs.Num();if(NumGameFeaturePluginsLoading>0){LoadState=ELyraExperienceLoadState::LoadingGameFeatures;for(constFString&PluginURL:GameFeaturePluginURLs){ULyraExperienceManager::NotifyOfPluginActivation(PluginURL);UGameFeaturesSubsystem::Get().LoadAndActivateGameFeaturePlugin(PluginURL,FGameFeaturePluginLoadComplete::CreateUObject(this,&ThisClass::OnGameFeaturePluginLoadComplete));}}else{OnExperienceFullLoadCompleted();}}

关键实现点：

验证加载状态和当前经验有效性
记录资源加载完成日志
收集游戏特性插件URL的Lambda函数
从经验定义和动作集中收集需要加载的游戏特性插件
转换状态为ELyraExperienceLoadState::LoadingGameFeatures
异步加载并激活游戏特性插件
支持无插件情况下直接完成加载

2.4 游戏特性插件加载完成

voidULyraExperienceManagerComponent::OnGameFeaturePluginLoadComplete(constUE::GameFeatures::FResult&Result){NumGameFeaturePluginsLoading--;if(NumGameFeaturePluginsLoading==0){OnExperienceFullLoadCompleted();}}

关键实现点：

递减正在加载的插件计数
当所有插件加载完成后，调用最终完成函数

2.5 经验完全加载完成

voidULyraExperienceManagerComponent::OnExperienceFullLoadCompleted(){check(LoadState!=ELyraExperienceLoadState::Loaded);if(LoadState!=ELyraExperienceLoadState::LoadingChaosTestingDelay){constfloatDelaySecs=LyraConsoleVariables::GetExperienceLoadDelayDuration();if(DelaySecs>0.0f){FTimerHandle DummyHandle;LoadState=ELyraExperienceLoadState::LoadingChaosTestingDelay;GetWorld()->GetTimerManager().SetTimer(DummyHandle,this,&ThisClass::OnExperienceFullLoadCompleted,DelaySecs,/*bLooping=*/false);return;}}LoadState=ELyraExperienceLoadState::ExecutingActions;FGameFeatureActivatingContext Context;constFWorldContext*ExistingWorldContext=GEngine->GetWorldContextFromWorld(GetWorld());if(ExistingWorldContext){Context.SetRequiredWorldContextHandle(ExistingWorldContext->ContextHandle);}autoActivateListOfActions=[&Context](constTArray<UGameFeatureAction*>&ActionList){for(UGameFeatureAction*Action:ActionList){if(Action!=nullptr){Action->OnGameFeatureRegistering();Action->OnGameFeatureLoading();Action->OnGameFeatureActivating(Context);}}};ActivateListOfActions(CurrentExperience->Actions);for(constTObjectPtr<ULyraExperienceActionSet>&ActionSet:CurrentExperience->ActionSets){if(ActionSet!=nullptr){ActivateListOfActions(ActionSet->Actions);}}LoadState=ELyraExperienceLoadState::Loaded;OnExperienceLoaded_HighPriority.Broadcast(CurrentExperience);OnExperienceLoaded_HighPriority.Clear();OnExperienceLoaded.Broadcast(CurrentExperience);OnExperienceLoaded.Clear();OnExperienceLoaded_LowPriority.Broadcast(CurrentExperience);OnExperienceLoaded_LowPriority.Clear();#if!UE_SERVERULyraSettingsLocal::Get()->OnExperienceLoaded();#endif}

关键实现点：

验证非已加载状态
支持混沌测试延迟（用于模拟加载延迟）
转换状态为ELyraExperienceLoadState::ExecutingActions
创建游戏特性激活上下文，包含世界上下文信息
激活动作列表的Lambda函数
执行经验定义和动作集中的所有动作（注册→加载→激活）
转换状态为ELyraExperienceLoadState::Loaded
按优先级广播加载完成事件：
- 高优先级（核心功能）
- 普通优先级
- 低优先级
在客户端调用本地设置的经验加载完成回调

3. 网络同步机制

Lyra的Experience系统支持网络同步，确保客户端和服务器使用相同的经验配置：

voidULyraExperienceManagerComponent::OnRep_CurrentExperience(){StartExperienceLoad();}voidULyraExperienceManagerComponent::GetLifetimeReplicatedProps(TArray<FLifetimeProperty>&OutLifetimeProps)const{Super::GetLifetimeReplicatedProps(OutLifetimeProps);DOREPLIFETIME(ThisClass,CurrentExperience);}

关键实现点：

当前经验通过DOREPLIFETIME宏自动复制到客户端
客户端在收到复制的经验后，自动调用StartExperienceLoad()开始加载
加载流程在客户端和服务器上独立执行，但最终结果一致

4. 加载状态管理

Experience系统使用ELyraExperienceLoadState枚举管理加载状态：

enumclassELyraExperienceLoadState{Unloaded,// 未加载状态Loading,// 加载经验资源LoadingGameFeatures,// 加载游戏特性插件LoadingChaosTestingDelay,// 混沌测试延迟ExecutingActions,// 执行经验动作Loaded,// 完全加载完成Deactivating// 停用经验};

5. 加载流程的取消和清理

系统支持加载过程中的取消处理：

Handle->BindCancelDelegate(FStreamableDelegate::CreateLambda([OnAssetsLoadedDelegate](){OnAssetsLoadedDelegate.ExecuteIfBound();}));

在组件结束时，会尝试停用已激活的游戏特性插件：

voidULyraExperienceManagerComponent::EndPlay(constEEndPlayReason::Type EndPlayReason){Super::EndPlay(EndPlayReason);for(constFString&PluginURL:GameFeaturePluginURLs){if(ULyraExperienceManager::RequestToDeactivatePlugin(PluginURL)){UGameFeaturesSubsystem::Get().DeactivateGameFeaturePlugin(PluginURL);}}// 停用和清理动作// ...}

6. 加载状态查询

boolULyraExperienceManagerComponent::IsExperienceLoaded()const{return(LoadState==ELyraExperienceLoadState::Loaded)&&(CurrentExperience!=nullptr);}constULyraExperienceDefinition*ULyraExperienceManagerComponent::GetCurrentExperienceChecked()const{check(LoadState==ELyraExperienceLoadState::Loaded);check(CurrentExperience!=nullptr);returnCurrentExperience;}