UE5 C++如何获取场景组件引用并调用开门交互方法

我在Unreal Engine 5用C++实现开门功能：从Sketchfab下载的门模型轴心位于中心，因此创建了Actor类ADoor1，给它添加UDoorSceneComponent作为根组件，将门Mesh挂载到该Scene Component上并调整位置，让Scene Component的轴心落在门的左下角。

已在角色类APlayerCharacter中实现Interact函数，当角色看向门并按下E键时触发；同时在UDoorSceneComponent中编写了OnInteract函数，负责将门旋转90度。当前的问题是不知道如何从角色类中调用这个OnInteract函数。

UDoorSceneComponent的OnInteract代码：

void UDoorSceneComponent::OnInteract()
{
    GEngine->AddOnScreenDebugMessage(-1, 15.0f, FColor::Yellow, TEXT("The function is called"));
    FRotator NewRotation = GetRelativeRotation();
    NewRotation.Yaw -= 90;
    SetRelativeRotation(NewRotation);
}

角色类APlayerCharacter的Interact代码：

void APlayerCharacter::Interact()
{
    FHitResult HitResult;

    //Makes an invisible line between the Start and End point
    FVector Start = FollowCamera->GetComponentLocation();
    FVector End = Start + FollowCamera->GetForwardVector() * InteractLengh;
    
    // if something is between the line then it stores the information in HitResult
    GetWorld()->LineTraceSingleByChannel(HitResult, Start, End, ECollisionChannel::ECC_Visibility);

    // Cast to Door. will return a nullptr if the object between Start and End wasnt the door
    ADoor1* DoorCast = Cast<ADoor1>(HitResult.GetActor());

    // if Door exists (not a nullptr) run the open door funcion
    if(DoorCast)
    {
        // Got the actor refrence
        AActor* Door1Act = UGameplayStatics::GetActorOfClass(GetWorld(), ADoor1::StaticClass());
        ADoor1* Door1Cast = Cast<ADoor1>(Door1Act);
        if(Door1Cast == nullptr)
        {
            GEngine->AddOnScreenDebugMessage(-1, 15.0f, FColor::Yellow, TEXT("nullptr"));
        }
        else
        {
            GEngine->AddOnScreenDebugMessage(-1, 15.0f, FColor::Yellow, TEXT("not nullptr"));
        }
    }
}

补充：我在ADoor1类中添加了默认值为true的bool变量test，在角色类的Interact函数中判断该变量为true时显示调试信息，运行后能成功显示。因此确定需要获取ADoor1类中UDoorSceneComponent的引用，但不知道具体实现方法。

步骤1：在ADoor1类中暴露UDoorSceneComponent引用 #

在ADoor1.h中，将UDoorSceneComponent声明为可访问的成员变量，用UPROPERTY标记让引擎识别：

// ADoor1.h
#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "DoorSceneComponent.h"
#include "Door1.generated.h"

UCLASS()
class YOURPROJECT_API ADoor1 : public AActor
{
    GENERATED_BODY()
    
public:    
    ADoor1();

    // 暴露DoorSceneComponent，允许外部访问
    UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = "Door")
    UDoorSceneComponent* DoorSceneComp;

protected:
    virtual void BeginPlay() override;

public:    
    virtual void Tick(float DeltaTime) override;
};

在ADoor1.cpp的构造函数中初始化该组件并设置为根组件：

// ADoor1.cpp
#include "Door1.h"

ADoor1::ADoor1()
{
    PrimaryActorTick.bCanEverTick = true;

    // 创建并初始化DoorSceneComponent
    DoorSceneComp = CreateDefaultSubobject<UDoorSceneComponent>(TEXT("DoorSceneComp"));
    RootComponent = DoorSceneComp;

    // 此处添加门Mesh挂载到DoorSceneComp的代码（你之前的实现逻辑）
}

步骤2：在角色类中调用OnInteract函数 #

修改角色类的Interact函数，直接通过LineTrace命中的DoorCast获取DoorSceneComp并调用OnInteract：

void APlayerCharacter::Interact()
{
    FHitResult HitResult;

    FVector Start = FollowCamera->GetComponentLocation();
    FVector End = Start + FollowCamera->GetForwardVector() * InteractLengh;
    
    GetWorld()->LineTraceSingleByChannel(HitResult, Start, End, ECollisionChannel::ECC_Visibility);

    ADoor1* DoorCast = Cast<ADoor1>(HitResult.GetActor());

    if(DoorCast)
    {
        // 检查DoorSceneComp是否有效，调用OnInteract
        if(DoorCast->DoorSceneComp)
        {
            DoorCast->DoorSceneComp->OnInteract();
            GEngine->AddOnScreenDebugMessage(-1, 15.0f, FColor::Green, TEXT("调用门交互函数成功"));
        }
        else
        {
            GEngine->AddOnScreenDebugMessage(-1, 15.0f, FColor::Red, TEXT("门组件为空"));
        }
    }
    else
    {
        GEngine->AddOnScreenDebugMessage(-1, 15.0f, FColor::Red, TEXT("未检测到可交互的门"));
    }
}

关键注意事项 #

• 确保UDoorSceneComponent的OnInteract函数是public权限，否则外部类无法调用：

  // DoorSceneComponent.h
  public:
      void OnInteract();
  

• 移除原代码中UGameplayStatics::GetActorOfClass的逻辑，该方法会获取场景中第一个ADoor1实例，而非玩家实际看向的门，会导致交互逻辑错误。

内容的提问来源于stack exchange，提问作者rdex999