UE5.2 LyraDemo源码阅读笔记（四）

上一篇（三）讲到在模式玩法UI点击Elimination进入淘汰赛模式。
UI选择点击Elimination后，触发蓝图W_HostSessionScreen的HostSession节点，有：
在这里插入图片描述
调用这个方法切换关卡后，会调用到LyraGameMode.cpp的
ALyraGameMode::InitGame(…)方法，也就是又开始重走一遍加载关卡相关内容的流程。

一、关于关卡Experience加载流程

1、切换关卡：CommonSessionSubSystem.cpp调用GetWorld()->ServerTravel(PendingTravelURL)切换到淘汰赛关卡。
2、初始化游戏：因为切换关卡，随后重新再触发ALyraGameMode.cpp的ALyraGameMode::InitGame()方法初始化关卡相关的Experience流程。
3、定位关卡ExperienceId：ALyraGameMode::HandleMatchAssignmentIfNotExpectingOne()，查找与当前淘汰赛关卡对应的ExperienceId。
4、设置ExperienceId：ALyraGameMode::OnMatchAssignmentGiven()里对ExperienceId进行赋值。
5、进行加载Experience数据资产：ULyraExperienceManagerComponent::SetCurrentExperience里对CurrentExperience赋值的同时，因为它设置了UPROPERTY(ReplicatedUsing=OnRep_CurrentExperience)，所以对它进行赋值时会调用同步方法OnRep_CurrentExperience::OnRep_CurrentExperience进行资源加载。
6、初始化Experience数据资产：加载完成后会调用ULyraExperienceManagerComponent::OnExperienceLoadComplete()，对Experience里带的插件进行加载。
代码 ULyraExperienceManagerComponent.cpp

void ULyraExperienceManagerComponent::OnExperienceFullLoadCompleted()
{
...auto ActivateListOfActions = [&Context](const TArray<UGameFeatureAction*>& ActionList){for (UGameFeatureAction* Action : ActionList){if (Action != nullptr){//@TODO: The fact that these don't take a world are potentially problematic in client-server PIE// The current behavior matches systems like gameplay tags where loading and registering apply to the entire process,// but actually applying the results to actors is restricted to a specific worldAction->OnGameFeatureRegistering();Action->OnGameFeatureLoading();Action->OnGameFeatureActivating(Context);}}};...
}

7、初始化Experience的插件列表：插件加载完成后，调用ULyraExperienceManagerComponent::OnExperienceFullLoadCompleted()这里会连续对插件里的Action列表进行注册、加载、激活。随后发出通知OnExperienceLoaded.Broadcast(CurrentExperience)。
8、生成玩家Pawn：Experience加载完成后发出通知后，触发LyraGameMode::InitGameState注册的方法ALyraGameMode::OnExperienceLoaded(const ULyraExperienceDefinition* CurrentExperience)，接着就在这个方法里调用RestartPlayer(PC)生成对应的玩家实体。