虚幻引擎 GameState 介绍

// MyGameState.h
#pragma once

#include "CoreMinimal.h"
#include "GameFramework/GameStateBase.h"
#include "Net/UnrealNetwork.h"
#include "MyGameState.generated.h"

UCLASS()
class MYGAME_API AMyGameState : public AGameStateBase
{
    GENERATED_BODY()

public:
    AMyGameState();

    // 团队分数（会自动同步到所有客户端）
    UPROPERTY(Replicated, BlueprintReadOnly, Category = "Score")
    int32 TeamAScore;

    UPROPERTY(Replicated, BlueprintReadOnly, Category = "Score")
    int32 TeamBScore;

    // 当前游戏阶段（如 WaitingToStart、InProgress、GameOver）
    UPROPERTY(Replicated, BlueprintReadOnly, Category = "GameState")
    FName CurrentGamePhase;

    // 服务器端修改分数的函数（蓝图可调用）
    UFUNCTION(BlueprintCallable, Category = "Score")
    void AddScoreToTeamA(int32 Points);

    UFUNCTION(BlueprintCallable, Category = "Score")
    void AddScoreToTeamB(int32 Points);

protected:
    virtual void GetLifetimeReplicatedProps(TArray<FLifetimeProperty>& OutLifetimeProps) const override;
};

// MyGameState.cpp
#include "MyGameState.h"
#include "Net/UnrealNetwork.h"

AMyGameState::AMyGameState()
{
    TeamAScore = 0;
    TeamBScore = 0;
    CurrentGamePhase = TEXT("WaitingToStart");
}

void AMyGameState::AddScoreToTeamA(int32 Points)
{
    // 关键：仅在服务器上修改复制属性！
    if (!HasAuthority())
    {
        return;
    }
    
    TeamAScore += Points;
    
    // 分数变化后，检查胜利条件（示例）
    if (TeamAScore >= 5)
    {
        CurrentGamePhase = TEXT("GameOver");
        // 可选择在此处广播游戏结束事件
    }
}

void AMyGameState::AddScoreToTeamB(int32 Points)
{
    if (!HasAuthority())
    {
        return;
    }
    
    TeamBScore += Points;
    
    if (TeamBScore >= 5)
    {
        CurrentGamePhase = TEXT("GameOver");
    }
}

void AMyGameState::GetLifetimeReplicatedProps(TArray<FLifetimeProperty>& OutLifetimeProps) const
{
    Super::GetLifetimeReplicatedProps(OutLifetimeProps);
    
    // 注册需要复制的属性
    DOREPLIFETIME(AMyGameState, TeamAScore);
    DOREPLIFETIME(AMyGameState, TeamBScore);
    DOREPLIFETIME(AMyGameState, CurrentGamePhase);
}