Specific Timeline member Variable makes EXCEPTION_ACCESS_VIOLATION

Development Programming & Scripting C++
, , , ,
1

First, here’s code :

//Constructor
AFPSurvivalCharacter::AFPSurvivalCharacter()
{
	// Set size for collision capsule
	GetCapsuleComponent()->InitCapsuleSize(55.f, 96.0f);

	// set our turn rates for input
	TurnRateGamepad = 45.f;

	// Create a CameraComponent	
	FirstPersonCameraComponent = CreateDefaultSubobject<UCameraComponent>(TEXT("FirstPersonCamera"));
	FirstPersonCameraComponent->SetupAttachment(GetCapsuleComponent());
	FirstPersonCameraComponent->SetRelativeLocation(FVector(-39.56f, 1.75f, 64.f)); // Position the camera
	FirstPersonCameraComponent->bUsePawnControlRotation = true;

	// Create a mesh component that will be used when being viewed from a '1st person' view (when controlling this pawn)
	Mesh1P = CreateDefaultSubobject<USkeletalMeshComponent>(TEXT("CharacterMesh1P"));
	Mesh1P->SetOnlyOwnerSee(true);
	Mesh1P->SetupAttachment(FirstPersonCameraComponent);
	Mesh1P->bCastDynamicShadow = false;
	Mesh1P->CastShadow = false;
	Mesh1P->SetRelativeRotation(FRotator(1.9f, -19.19f, 5.2f));
	Mesh1P->SetRelativeLocation(FVector(-0.5f, -4.4f, -155.7f));

	SprintMultiplier = 1.7f;
	CrouchMultiplier = 0.6f;

	SpeedMap.Reserve(3);

	SpeedMap.Add(EMovementState::Walking, GetCharacterMovement()->MaxWalkSpeed);
	SpeedMap.Add(EMovementState::Sprinting, GetCharacterMovement()->MaxWalkSpeed * SprintMultiplier);
	SpeedMap.Add(EMovementState::Crouching, GetCharacterMovement()->MaxWalkSpeed * CrouchMultiplier);
	SpeedMap.Add(EMovementState::Sliding, NULL);
	
	ButtonPressed.Reserve(2);

	ButtonPressed.Add("Sprint", false);
	ButtonPressed.Add("Crouch", false);
	
	CurrentJumpCount = 0;
	MaxJumpCount = 2;
	
	MovementState = EMovementState::Walking;
	PrevMovementState = EMovementState::Walking;
	
	SlideTimeline = CreateDefaultSubobject<UTimelineComponent>(TEXT("SlideTimeline"));
	SmoothCrouchingTimeline = CreateDefaultSubobject<UTimelineComponent>(TEXT("CrouchingTimeline"));
	CameraTiltTimeline = CreateDefaultSubobject<UTimelineComponent>(TEXT("TiltTimeline"));
	
	StandingCapsuleHalfHeight = GetCapsuleComponent()->GetScaledCapsuleHalfHeight();
	StandingCameraZOffset = GetFirstPersonCameraComponent()->GetRelativeLocation().Z;

	DefaultGroundFriction = GetCharacterMovement()->GroundFriction;
	DefaultBrakingDeceleration = GetCharacterMovement()->BrakingDecelerationWalking;
}

void AFPSurvivalCharacter::BeginPlay()
{
	// Call the base class  
	Super::BeginPlay();
	
	SlideTimelineFunction.BindUFunction(this, FName("SlideTimelineReturn"));
	SlideTimeline->AddEvent(0, SlideTimelineFunction);
	SlideTimeline->SetTimelineLength(1.0);
	SlideTimeline->SetLooping(true);
	
	CameraTiltTimelineFunction.BindUFunction(this, FName("CameraTiltReturn"));
	if(CameraTiltCurveFloat)
	{
		CameraTiltTimeline->AddInterpFloat(CameraTiltCurveFloat, CameraTiltTimelineFunction);
		CameraTiltTimeline->SetTimelineLength(0.3);
		CameraTiltTimeline->SetLooping(false);
	}
	
	SmoothCrouchTimelineFunction.BindUFunction(this, FName("SmoothCrouchTimelineReturn"));
	if(SmoothCrouchingCurveFloat)
	{
                //Error! WHY??????
		SmoothCrouchingTimeline->AddInterpFloat(SmoothCrouchingCurveFloat, SmoothCrouchTimelineFunction);
		SmoothCrouchingTimeline->SetTimelineLength(0.3);
		SmoothCrouchingTimeline->SetLooping(false);
	}
}

void AFPSurvivalCharacter::SmoothCrouchTimelineReturn(float Value)
{
	const auto CrouchedHeight = GetCharacterMovement()->GetCrouchedHalfHeight();
	GetCapsuleComponent()->SetCapsuleHalfHeight(FMath::Lerp(CrouchedHeight, StandingCapsuleHalfHeight, Value));

	const auto RelativeLocation = FirstPersonCameraComponent->GetRelativeLocation();
	FirstPersonCameraComponent->SetRelativeLocation(FVector(RelativeLocation.X, RelativeLocation.Y, (FMath::Lerp(CrouchedHeight, StandingCameraZOffset, Value))));
}

void AFPSurvivalCharacter::SlideTimelineReturn()
{
	const auto SlideDirection = CalculateFloorInfluence(GetCharacterMovement()->CurrentFloor.HitResult.Normal);

	GetCharacterMovement()->AddForce(SlideDirection);

	if(GetVelocity().Length() > SpeedMap[EMovementState::Sprinting])
	{
		auto velocity = GetVelocity();
		velocity.Normalize();
		
		GetCharacterMovement()->Velocity = velocity * SpeedMap[EMovementState::Sprinting];
	}
	if(GetVelocity().Length() < SpeedMap[EMovementState::Crouching])
	{
		ResolveMovementState();
	}
}

and here’s Crash Log…

Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x00000000000000f0

UnrealEditor_Engine!FTimeline::AddInterpFloat() [D:uild++UE5SyncEngineSourceRuntimeEnginePrivateTimeline.cpp:114]

UnrealEditor_Engine!UTimelineComponent::AddInterpFloat() [D:uild++UE5SyncEngineSourceRuntimeEnginePrivateTimeline.cpp:777]

UnrealEditor_FPSurvival_4743!AFPSurvivalCharacter::BeginPlay() [C:UserskcjseDesktopProject-FPSurvivalSourceFPSurvivalFPSurvivalCharacter.cpp:93]

UnrealEditor_Engine!AActor::DispatchBeginPlay() [D:uild++UE5SyncEngineSourceRuntimeEnginePrivateActor.cpp:3849]

and Github Repo - (Project-FPSurvival/FPSurvivalCharacter.cpp at main · kcjsend2/Project-FPSurvival · GitHub)

When I access member function of SmoothCrouchingTimeline, UE5 crashes.
Project is based on FPS Template.

I try to figure this out for three days, but I CANT FIND ANYTHING WRONG…
Spelling, GC, UPROPERTY, UFUNCTION… Everything looks fine, but it doesn’t work.
this makes me pain a lot… please help.

2

If you breakpoint in BeginPlay() on the CameraTiltTimeline->AddInterpFloat(CameraTiltCurveFloat, CameraTiltTimelineFunction); line, is CameraTiltTimeline null?

3

CameraTiltTimeline is Not Null, but I found that SmoothCrouchingTimeline is NULL!
why is this happens? I think it was Initialized in Constructor…

4

‘SmoothCrouchingTimeline’ is surely initialized in Constructor of AFPSurvivalCharacter, but when BeginPlay Executed, it just become NULL value…
I have no idea why this is happening.

5

I’d add a check with a log or ensure before you dereference the pointer, just to stop it crashing. What does your header look like? Is SmoothCrouchingTimeline a UPROPERTY? Is there a particular instance in the world that’s breaking - if you remove it and add a new one, does that also break?

6

Yes, SmoothCrouchingTimeline is UPROPERTY, and next one - there’s nothing occurs breaking, it’s just basic FPS template scene. so there’s just box, floors, etc…

7

I know it sounds really weird, but changing IDE from Rider to VS solved the problem…

8

Ah you may have just needed a clean rebuild. Object/intermediate files can very occasionally get in a bad state.