调用 AI MoveToLocation 时 Unreal 崩溃

Question

我首先在 Blueprint 中测试了以下代码，并希望将其翻译成 C++。我正在尝试创建一个带有 triggerSphere 的 npc，它激活 onOverlap 并让 Npc 朝玩家来自的相反方向走开。当我玩虚幻编辑器并靠近 Npc 时，它会崩溃。问题出在 AiController 的 MoveToLocation 上，但我不知道为什么。

这是蓝图（如果质量不好，请见谅）

这里是 Npc 的 AiController 文件 .h 文件：

#include "CoreMinimal.h"
#include "AIController.h"
#include "SpiderAIController.generated.h"

/**
 * 
 */
UCLASS()
class SPIDERPROJECT0710_API ASpiderAIController : public AAIController
{
    GENERATED_BODY()

protected:
    virtual void BeginPlay() override;
    
    

public:
    UFUNCTION()
    void WalkAway(FVector Location, float Var); 
};

.cpp

#include "SpiderAIController.h"

void ASpiderAIController::BeginPlay()
 {
    Super::BeginPlay();   
 }

 void ASpiderAIController::WalkAway(FVector Location, float Var)
 {
    
    MoveToLocation(Location, Var);
 }

这里是 Npc 的文件：

.h 文件的必要部分

private:
    UPROPERTY(VisibleAnywhere, Category = "Switch Components")         class USphereComponent* TriggerSphere;

    UPROPERTY()
    class ASpiderAIController* AIController;
     
    UFUNCTION()
    void OnOverlapBegin(class UPrimitiveComponent* OverlappedComp, class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult);

    
    //UFUNCTION()
    //void OnOverlapEnd(class UPrimitiveComponent* OverlappedComp, class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex);

};

cpp 文件：

#include "SpiderCharacter.h"
#include "Components/SphereComponent.h"
#include "SpiderAIController.h"

// Sets default values
ASpiderCharacter::ASpiderCharacter()
{
    // Set this character to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
    PrimaryActorTick.bCanEverTick = true;

    TriggerSphere = CreateDefaultSubobject<USphereComponent>(TEXT("Trigger Sphere"));
    TriggerSphere->InitSphereRadius(105.0f);
    TriggerSphere->SetCollisionProfileName(TEXT("Trigger"));
    TriggerSphere->SetupAttachment(RootComponent);

    TriggerSphere->OnComponentBeginOverlap.AddDynamic(this, &ASpiderCharacter::OnOverlapBegin); 
    AIController = Cast<ASpiderAIController>(GetController());

    
}

void ASpiderCharacter::OnOverlapBegin(class UPrimitiveComponent* OverlappedComp, class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult)
{
    if (OtherActor && (OtherActor != this) && OtherComp) 
    {
        //get Location and Roation of PlayerCharacter
        FVector PlayerPosition = GetWorld()->GetFirstPlayerController()->GetPawn()->GetActorLocation();
        FRotator PlayerRotation = GetWorld()->GetFirstPlayerController()->GetPawn()->GetActorRotation();
        FVector NewLocation = FVector(PlayerPosition.X -500.f,PlayerPosition.Y - 500.f, PlayerPosition.Z);
        float Var = 100.f;

        SetActorRotation(PlayerRotation);
        AIController->WalkAway(NewLocation, Var);
        //SetActorLocation(NewLocation);

        
        UE_LOG(LogTemp,Warning,TEXT("MyCharacter's Location is %s"),  *OtherActor->GetName());
    }
} 

来自 Unreal 的错误消息：

LoginId:c4c2e10f47cd9a4f6992fd821aae5406 EpicAccountId:92760ac7ea0e4f249688fd7737d3a55d

Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x00000000000003b0

UE4Editor_AIModule UE4Editor_SpiderProject0710_4739!ASpiderAIController::WalkAway() [C:\Users\alexa\OneDrive\Desktop\Udemy\Unreal Engine\SpiderProject0710\Source\SpiderProject0710\SpiderAIController.cpp:19] 
UE4Editor_SpiderProject0710_4739!ASpiderCharacter::OnOverlapBegin() [C:\Users\alexa\OneDrive\Desktop\Udemy\Unreal Engine\SpiderProject0710\Source\SpiderProject0710\SpiderCharacter.cpp:62] 
UE4Editor_SpiderProject0710_4739!ASpiderCharacter::execOnOverlapBegin() [C:\Users\alexa\OneDrive\Desktop\Udemy\Unreal Engine\SpiderProject0710\Intermediate\Build\Win64\UE4Editor\Inc\SpiderProject0710\SpiderCharacter.gen.cpp:38] 
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_Engine
UE4Editor_Engine
UE4Editor_Engine
UE4Editor_Engine
UE4Editor_Engine
UE4Editor_Engine
UE4Editor_Engine
UE4Editor_Engine
UE4Editor_Engine
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UE4Editor_Engine
UE4Editor_Engine
UE4Editor_Engine
UE4Editor_Core
UE4Editor_Core
UE4Editor_Core
UE4Editor_Engine
UE4Editor_Engine
UE4Editor_Engine
UE4Editor_Engine
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor
UE4Editor
UE4Editor
UE4Editor
UE4Editor
kernel32
ntdll

Answer 1

我发现了问题。我需要在 BeginPlay 上获取 PlayerPawn 和 AiController，而不是在类构造函数中。我也重构了代码。

npc .h：

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Character.h"
#include "SpiderCharacter.generated.h"

UCLASS()
class SPIDERPROJECT0710_API ASpiderCharacter : public ACharacter
{
    GENERATED_BODY()

public:
    // Sets default values for this character's properties
    ASpiderCharacter();

protected:
    // Called when the game starts or when spawned
    virtual void BeginPlay() override;

public: 
    // Called every frame
    virtual void Tick(float DeltaTime) override;

    // Called to bind functionality to input
    virtual void SetupPlayerInputComponent(class UInputComponent* PlayerInputComponent) override;


private:
    UPROPERTY(VisibleAnywhere, Category = "Switch Components")         class USphereComponent* TriggerSphere;

    UPROPERTY()
    class ASpiderAIController* AIController;

    UPROPERTY()
    class APawn* PlayerPawn;
     
    UFUNCTION()
    void OnOverlapBegin(class UPrimitiveComponent* OverlappedComp, class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult);

    
    //UFUNCTION()
    //void OnOverlapEnd(class UPrimitiveComponent* OverlappedComp, class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex);

};

和 cpp：

#include "SpiderCharacter.h"
#include "Components/SphereComponent.h"
#include "SpiderAIController.h"
#include "Kismet/GameplayStatics.h"

// Sets default values
ASpiderCharacter::ASpiderCharacter()
{
    // Set this character to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
    PrimaryActorTick.bCanEverTick = true;

    TriggerSphere = CreateDefaultSubobject<USphereComponent>(TEXT("Trigger Sphere"));
    TriggerSphere->InitSphereRadius(105.0f);
    TriggerSphere->SetCollisionProfileName(TEXT("Trigger"));
    TriggerSphere->SetupAttachment(RootComponent);

    TriggerSphere->OnComponentBeginOverlap.AddDynamic(this, &ASpiderCharacter::OnOverlapBegin); 
    


    
}

// Called when the game starts or when spawned
void ASpiderCharacter::BeginPlay()
{
    Super::BeginPlay();
    AIController = Cast<ASpiderAIController>(GetController());
    PlayerPawn = UGameplayStatics::GetPlayerPawn(GetWorld(), 0);
    //UE_LOG(LogTemp,Warning,TEXT("MyCharacter is %s"),  *PlayerPawn->GetName());
    
}

// Called every frame
void ASpiderCharacter::Tick(float DeltaTime)
{
    Super::Tick(DeltaTime);

}

// Called to bind functionality to input
void ASpiderCharacter::SetupPlayerInputComponent(UInputComponent* PlayerInputComponent)
{
    Super::SetupPlayerInputComponent(PlayerInputComponent);

}

//Overlap Function
void ASpiderCharacter::OnOverlapBegin(class UPrimitiveComponent* OverlappedComp, class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult)
{
    if (OtherActor && (OtherActor != this) && OtherComp) 
    {
        //get Location and Roation of PlayerCharacter
        //FVector PlayerPosition = GetWorld()->GetFirstPlayerController()->GetPawn()->GetActorLocation();
        //FRotator PlayerRotation = GetWorld()->GetFirstPlayerController()->GetPawn()->GetActorRotation();
        FVector PlayerPosition = PlayerPawn->GetActorLocation();
        FRotator PlayerRotation = PlayerPawn->GetActorRotation();

        FVector NewLocation = FVector(PlayerPosition.X -500.f,PlayerPosition.Y - 500.f, PlayerPosition.Z);
        float Var = 100.f;

        SetActorRotation(PlayerRotation);
        AIController->WalkAway(NewLocation, Var);
        //SetActorLocation(NewLocation);

        
        UE_LOG(LogTemp,Warning,TEXT("MyCharacter's Location is %s"),  *OtherActor->GetName());
    }
}