Random Access Violation crashing

[mectorn]

Hello everyone. I have a test function on a UObject script that gets called when I press LMB from another script. When I spam click it the game crashes with this:

Exception thrown at 0x000000020000005D in UnrealEditor-Win64-DebugGame.exe: 0xC0000005: Access violation executing location 0x000000020000005D.

Unhandled exception at 0x000000020000005D in UnrealEditor-Win64-DebugGame.exe: 0xC0000005: Access violation executing location 0x000000020000005D.

This happens every time, but I have to spam fire button for about 1 minute for it to crash.

{
    FHitResult hitInfo;

    if (!PlayerCamera)
    {
        GEngine->AddOnScreenDebugMessage(-1, 35.0, FColor::Red, "Null Ptr Camera");
        return;
    }

    FVector EndVector = PlayerCamera->GetCameraLocation() + PlayerCamera->GetActorForwardVector() * 900;

    bool hitBool = GetWorld()->LineTraceSingleByObjectType(hitInfo, PlayerCamera->GetCameraLocation(), EndVector, ECollisionChannel::ECC_PhysicsBody);

    if (hitBool) {
        FVector hitPoint = hitInfo.ImpactPoint;
        AActor* MyActor = hitInfo.GetActor();

        if (MyActor)
        {

            UStaticMeshComponent* Mesh = Cast<UStaticMeshComponent>(MyActor->GetRootComponent());
            if (Mesh)
            {
                Mesh->AddImpulseAtLocation(PlayerCamera->GetActorForwardVector() * 1500, hitPoint);
            }
            else
            {
                GEngine->AddOnScreenDebugMessage(-1, 35.0, FColor::Red, "Null Ptr mesh");
            }
        }
        else
        {
            GEngine->AddOnScreenDebugMessage(-1, 35.0, FColor::Red, "Null Ptr actor");
        }

    }
}

Also VS adds breakpoint symbol to bool hitBool = GetWorld()->LineTraceSingleByObjectType(hitInfo, PlayerCamera->GetCameraLocation(), EndVector, ECollisionChannel::ECC_PhysicsBody); line after the crash.

[NeoGothique (SJ Barras)]

Probably post the stack trace or run it with the debugger, it is possible GetWorld() returns null and you are using it without a check

[mectorn]

I’ve tried creating UWorld variable for the world and now the program crashes after I use GetWorld(). Is there something wrong with using GetWorld() inside an UObject?

[NeoGothique (SJ Barras)]

I believe it is not fully implemented in UObject the same way as it is in AActor for example, you can use GEngine->GetWorld() for a more global method

[mectorn]

This has fixed the crash but now I see that it always returns null pointer

[NeoGothique (SJ Barras)]

Seems there are some extra considerations when using GetWorld() inside a UObject:

Where to get the WorldContextObject when World is null?

This was amazing! I’ve been stuck for days trying to figure this out! For those wondering, I’ve tried the following method but it kept crashing UE since they were returning NULL UWorld* World = GEngine->GameViewport->GetWorld();

GetWorld is null in UObject classes

In my source i’m using “action” classes which inherit UObject to perform multiple actions on the character. When calling the GetWorld() inside the action classes, it return null. CurrentAction = NewObject<USwatAction>(this, FocusedActorAction, FName(TEXT("CharacterAction")), RF_Standalone); CurrentAction->StartAction(TargetActor); where CurrentAction and ActionClass are TSubclassOf<class USwatAction> FocusedActorAction; class USwatAction* CurrentAction; My game crashes on calling th…

[mectorn]

Thank you. I’ve decided to just add an AActor variable to the script and get world through it and it works.