Release Component causing crash

Development Programming & Scripting C++
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1

Hi there, I have been experiencing crashes while making my demo on UE4. The crash report said there was something wrong with the “Release Function” I have for my component:

void UGrabber::Grab()
{
	UE_LOG(LogTemp, Warning, TEXT("Grabbed"));
	FHitResult HitResult = GetFirstPhysicsBodyInReach();
	UPrimitiveComponent* ComponentGrab = HitResult.GetComponent();
	if (HitResult.GetActor())
	{
		PhysicsHandle->GrabComponentAtLocation(ComponentGrab, NAME_None, GetPlayerReach());
	}
	Grabbed = true;

}
void UGrabber::Release()
{
	UE_LOG(LogTemp, Warning, TEXT("Released"));
	int pulse = 1400;
	FHitResult HitResult = GetFirstPhysicsBodyInReach();
	UPrimitiveComponent* ComponentGrab = HitResult.GetComponent();
	if (Grabbed)
	{
		PhysicsHandle->ReleaseComponent();
		ComponentGrab->AddImpulse(
			GetWorld()->GetFirstPlayerController()->AActor::GetActorForwardVector() * pulse,
			NAME_None,
			true
		);
	}
	Grabbed = false;

And the error messsages:

LoginId:c1c6744445b8f3eac10f52a24f7db053
EpicAccountId:faa1a0f7440240ec8bc49902f8c952de

Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x0000000000000000

UE4Editor_Demo_9030!UGrabber::Release() [E:\Uprojectfold\Demo\Source\Demo\Grabber.cpp:135]
UE4Editor_Engine
UE4Editor_Engine
UE4Editor_Engine
UE4Editor_Engine
UE4Editor_Engine
UE4Editor_Engine
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
UE4Editor
kernel32
ntdll

The crashes started after I implemented the AddImpulse function.
Also my pawn gets really bouncy and moves uncontrollably if it runs into objects, what can I do to fix that?
Thx!

2

ComponentGrab might be nullptr.

Also, if Grabbed is a bool - you might want to use unreal engine coding standards and change its name to bGrabbed.

2 Likes
3

I think the same. If I were you I would test that code in debug mode, in order to see what it nullptr