1. Network Architecture

2.Replication

Information is synchronized from the server to the customer service (one-way), only Actor and its derived classes have the ability of Replication

type

Actor Replication（类）
Property Replication
Compoenent Replication (component)

Two meanings of Actor Replication

1. The server is generated, and the client is also generated (a replication object is generated on the server)

2. All attributes of the current Actor are copied, components are copied, and the master switch of RPC

Enable Actor Replication

Blueprint: Check "Replication"

C++：bReplication = true；

In the constructor in the cpp file

Example demo

Switch Has Authority (Authority: equivalent to the server, Remote: equivalent to the client)

Test the setup while connected to the Internet

unchecked

After checking

Property Replication (setting method for attribute replication)

Blueprint: Replication of the property is set to Replicated

Set on the server side, if the server-side Replication is not set to Replicated, the client cannot see the attribute

Before not set

after setting

C++：

Add UPROPERTY(Replication) before the attribute
In the .cpp file, add in the GetLifetimeReplicatedProps function: DOREPLIFETIME (class name, variable name) does not need to declare this function

Add attribute
VisibleAnywhere: also visible in the blueprint

add header file

RepNotift (replication notification)

If a variable is set to Rep_Notify, both the server and the client receiving the value can call a custom function when the variable is replicated

C++ only calls functions on the client side

Blueprint: Replication of the attribute is set to RepNotify, which is automatically generated

When the attribute Replication is set to RepNotify, an ONRep function will be automatically generated

The set variable will change after setting

Both the server and the client in the blueprint can call

c++：UPROPERTY(ReolicatedUsing=xxx)

make variable copyable

3.Ownership

As many players join as there are several Connections

The role of ownership

RPC needs to determine which client will execute the RPC running on the client
Actor replication and connection dependencies
Actor property copy condition when owner is involved

Set/Change/Get Ownership

SpawnActor (there is Owner in SpawnParanmeters)
SetOwner
Possess(OnPossess->PosssesssedBy->SetOwner),UnPossess

4.Actor Role

Authority: have control

Simulated Proxy: simulated proxy

Autonomous Proxy: Autonomous Proxy

Server: server, Client: client. big smiley face

5.RPC

Similar to a function call, but not necessarily executed locally

can be realised:

The client calls the server to execute
The server calls the client to execute

Can not have a return value, the default is "unreliable" (can be set to reliable: Reliable)

RPC settings

blueprint:

The Replicates option of the CustomEvent custom event is set to

Run On Server (server execution)
Run On Owning Client (client execution)
Net MultiCast (all endpoints do)

C++

To declare a function as RPC, simply put

Server
Client
NetMulticast

keyword added to the UFUNCTION declaration

example

First check Replication to make it replicable

concrete blueprint

detailed blueprint

Authorrity: on behalf of the server, Remote: on behalf of the client

Is Locally Controlled: Whether it is a local controller, and whether it is a big smiley face

Get Local Role: get the local role, and the smiling face (judging whether it is a big smiling face)

The client call event is generated on the server side,

Server-side implementation only (server generates one, client copies one)

Client-only implementation (two clients spawned by the server, replicating itself)

all achieved

Test Multicast

Only press the right mouse button on the server to print, and both the server and the client will print

Test Server

Only server side printing

Test Client

Create a GameMode first (because GameMode only exists on the server side)

Blueprints in GameMode

Event onPostLogin: Called when a player connects

Get Remote Role: Get the remote role

Get Local Role: Get the local role

Has Authority: Whether it is Authority (equivalent to whether it is a server)

final blueprint

GameMode

Call Test Client

Call Test Multicast