UE网络-WithNetSerializer详解

发表于 2024-05-15 更新于 2024-04-30 分类于 UE ， UE网络， WithNetSerializer详解阅读次数：本文字数： 567 阅读时长 ≈ 2 分钟

WithNetSerializer是什么

在网络同步过程中, 序列化使用自定义结构体自身序列化函数:NetSerialize.

自定义结构体指定WithNetSerializer

USTRUCT()
struct FExampleStruct1
{
    GENERATED_USTRUCT_BODY()
public:
    UPROPERTY()
    int32		ExampleIntProperty;

    /**
     * @param Ar			FArchive to read or write from.
     * @param Map			PackageMap used to resolve references to UObject*
     * @param bOutSuccess	return value to signify if the serialization was succesfull (if false, an error will be logged by the calling function)
     *
     * @return return true if the serialization was fully mapped. If false, the property will be considered 'dirty' and will replicate again on the next update.
     *	This is needed for UActor* properties. If an actor's Actorchannel is not fully mapped, properties referencing it must stay dirty.
     *	Note that UPackageMap::SerializeObject returns false if an object is unmapped. Generally, you will want to return false from your ::NetSerialize
     *  if you make any calls to ::SerializeObject that return false.
     *
    */
    bool NetSerialize(FArchive& Ar, class UPackageMap* Map, bool& bOutSuccess);
};

template<>
struct TStructOpsTypeTraits< FExampleStruct1 > : public TStructOpsTypeTraitsBase2< FExampleStruct1 >
{
    enum
    {
        WithNetSerializer = true,
    };
};

将WithNetSerializer映射到EStructFlags::STRUCT_NetSerializeNative

构建UScriptStruct

在PreInit时候,构建UScriptStruct

将WithNetSerializer属性映射到EStructFlags::STRUCT_NetSerializeNative

构建UScriptStruct, 通过模板, 指定WithNetSerializer属性.

好了, 到此为止, 已经将我们指定的WithNetSerializer映射到EStructFlags::STRUCT_NetSerializeNative上了. 即UScriptStruct.StructFlags已经包含EStructFlags::STRUCT_NetSerializeNative属性.

将EStructFlags::STRUCT_NetSerializeNative映射到ERepParentFlags::IsNetSerialize

在创建RepLayout时(例如:FRepLayout::InitFromClass), 设置RepStruct信息.

这样, 就将STRUCT_NetSerializeNative属性映射成IsNetSerialize, 并存储在FRepParentCmd.Flags中.

使用ERepParentFlags::IsNetSerialize

通过1-4,已经将WithNetSerializer->EStructFlags::STRUCT_NetSerializeNative->ERepParentFlags::IsNetSerialize的转化讲清楚了, 并最终存储在FRepParentCmd.Flags中. 这里所说的使用ERepParentFlags::IsNetSerialize其实包括EStructFlags::STRUCT_NetSerializeNative和ERepParentFlags::IsNetSerialize的使用.

在序列化时候, 调用自身定义函数

--UNetDriver.TickFlush()
 |--UNetDriver.ServerReplicateActors()
 | |--UNetDriver.ServerReplicateActors_ProcessPrioritizedActors()
 | | |--UActorChannel.ReplicateActor()
 | | | |--FObjectReplicator.ReplicateProperties()
 | | | | |--FRepLayout.ReplicateProperties()
 | | | | | |--FRepLayout.SendProperties()
 | | | | | | |--FRepLayout.SendProperties_r()
 | | | | | | | |--FStructProperty.NetSerializeItem()
 | | | | | | | | |--FExampleStruct.NetSerialize()