ue4-Network相关-变量同步

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蓝图 or c++ 的 变量同步

变量同步

  • 变量同步的原则是：一定要在服务端修改该变量，也就是rpc调用 Run On Server方法（ue4-Network相关-rpc调用）中修改该变量，才会根据变量属性是否为 Replicated 决定是否同步给 服务器和所有客户端

  • 蓝图中同步：

  • c++中同步：

    1. 在变量中加入标记 Replicated

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      UPROPERTY(Replicated, EditAnywhere, BlueprintReadWrite, Category = AMyNetCharacter)
      	int32 Cash;

    2. 重写 AActor 的 GetLifetimeReplicatedProps 方法，加入需要同步的变量 Cash

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      #include "Net/UnrealNetwork.h" //包含net相关头文件

      void AMyNetCharacter::GetLifetimeReplicatedProps(TArray<FLifetimeProperty>& OutLifetimeProps) const
      {
      	Super::GetLifetimeReplicatedProps(OutLifetimeProps);
      	DOREPLIFETIME(AMyNetCharacter, Cash);
      }

  1. 在构造函数中修改成员 bReplicates 为 true

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    AMyNetCharacter::AMyNetCharacter()
    {
    	Cash = 456;
    	bReplicates = true;
    }

    • 变量标记的可选值，和蓝图对应，意思差不多

      • NotReplicated：服务端不会同步给所有客户端
      • Replicated：在服务端修改，会同步给其他客户端
      • ReplicatedUsing：选择这个的时候，需要指定一个 Var 改变时对应的 OnRep_Var（命名无特殊要求，不过还是按照蓝图生成的规则以 OnRep_ 前缀）,一定要加上 UFUNCTION 给反射系统，在服务端修改 Var 的时候会回调这个 OnRep_Var 方法。规则和 Replicated 差不多，示例如下： 
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        UFUNCTION(BlueprintCallable, Category = AMyNetCharacter)
        	virtual void OnRep_Money();

        void AMyNetCharacter::OnRep_Money()
        {
        	FString msg = FString::Printf(TEXT("--- OnRep_Money money:%d"), Money);
        	GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, *msg);
        }

        	// 指定回调函数为 OnRep_Money
        	UPROPERTY(ReplicatedUsing = OnRep_Money, EditAnywhere, BlueprintReadWrite, Category = AMyNetCharacter)
        		int32 Money;

        	//重写的 GetLifetimeReplicatedProps 方法中加入需要同步的变量
        	DOREPLIFETIME(AMyNetCharacter, Money);

    • 参考：https://docs-origin.unrealengine.com/latest/INT/Gameplay/Networking/Actors/Properties/index.html

有条件的同步给不同链接中的actor的变量

  • 会在服务端同步 Replicated 变量给所有客户端前做二次检查，满足条件的客户端才会被同步
  • 实际的作用场景，例如：本机控制的actor的一些属性，本地修改（假修改），同时告诉服务端修改（真实修改，同时做校验），然后同步给除本机外的所有客户端上的该actor修改，因为本机已经自己修改了。

  1. 做法和上面差不多，只需要修改第二步， DOREPLIFETIME_CONDITION

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    	UPROPERTY(Replicated, EditAnywhere, BlueprintReadWrite, Category = AMyNetCharacter)
    		int32 Item1;

    void AMyNetCharacter::GetLifetimeReplicatedProps(TArray<FLifetimeProperty>& OutLifetimeProps) const
    {
    	Super::GetLifetimeReplicatedProps(OutLifetimeProps);

    	DOREPLIFETIME_CONDITION(AMyNetCharacter, Item1, COND_AutonomousOnly); //只给自己控制的actor同步Item1变量
    }

  2. 然后在rpc调用服务端方法修改Item1变量，就能看到只有自己控制的actor中Item1改变了，其他客户端的没有改变，是因为这个 COND_AutonomousOnly 标记。
    这里写图片描述

  • c++中的控制条件枚举

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    /** Secondary condition to check before considering the replication of a lifetime property. */
    UENUM(BlueprintType)
    enum ELifetimeCondition
    {
    	COND_None = 0							UMETA(DisplayName = "None"),							// This property has no condition, and will send anytime it changes
    	COND_InitialOnly = 1					UMETA(DisplayName = "Initial Only"),					// This property will only attempt to send on the initial bunch
    	COND_OwnerOnly = 2						UMETA(DisplayName = "Owner Only"),						// This property will only send to the actor's owner
    	COND_SkipOwner = 3						UMETA(DisplayName = "Skip Owner"),						// This property send to every connection EXCEPT the owner
    	COND_SimulatedOnly = 4					UMETA(DisplayName = "Simulated Only"),					// This property will only send to simulated actors
    	COND_AutonomousOnly = 5					UMETA(DisplayName = "Autonomous Only"),					// This property will only send to autonomous actors
    	COND_SimulatedOrPhysics = 6				UMETA(DisplayName = "Simulated Or Physics"),			// This property will send to simulated OR bRepPhysics actors
    	COND_InitialOrOwner = 7					UMETA(DisplayName = "Initial Or Owner"),				// This property will send on the initial packet, or to the actors owner
    	COND_Custom = 8							UMETA(DisplayName = "Custom"),							// This property has no particular condition, but wants the ability to toggle on/off via SetCustomIsActiveOverride
    	COND_ReplayOrOwner = 9					UMETA(DisplayName = "Replay Or Owner"),					// This property will only send to the replay connection, or to the actors owner
    	COND_ReplayOnly = 10					UMETA(DisplayName = "Replay Only"),						// This property will only send to the replay connection
    	COND_SimulatedOnlyNoReplay = 11			UMETA(DisplayName = "Simulated Only No Replay"),		// This property will send to actors only, but not to replay connections
    	COND_SimulatedOrPhysicsNoReplay = 12	UMETA(DisplayName = "Simulated Or Physics No Replay"),	// This property will send to simulated Or bRepPhysics actors, but not to replay connections
    	COND_Max = 13							UMETA(Hidden)
    };

  • 蓝图中则有个 Replication Condition 下拉选项：
    这里写图片描述

  • 参考：https://docs-origin.unrealengine.com/latest/INT/Gameplay/Networking/Actors/Properties/Conditions/index.html