C++ Spline SetStartAndEnd crash

Development Programming & Scripting
1

So I am working on a script that adds meshes to a spline in the constructor.

But when compiling I keep getting a crash on the following line:

SMC->SetStartAndEnd(Start, StartTang, End, EndTang);

If that line is removed everything is working fine… Here is the full code.

ABSSpline::ABSSpline(const class FObjectInitializer& PCIP)
	: Super(PCIP)
{
	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;

	SplineComponent = PCIP.CreateDefaultSubobject<USplineComponent>(this, TEXT("Spline"));
	
	RootComponent = SplineComponent;

	if (SplineComponent)
	{
		SplineComponent->SetMobility(EComponentMobility::Movable);
	}

	UStaticMesh* Cyl = Cast<UStaticMesh>(StaticLoadObject(UStaticMesh::StaticClass(), NULL, TEXT("/Engine/BasicShapes/Cylinder.Cylinder")));
	
	for (int i = 0; i < SplineComponent->GetNumSplinePoints() - 2; i++)
	{
		SMC = PCIP.CreateDefaultSubobject<USplineMeshComponent>(this, TEXT("SplineMesh"));
		SMC->SetStaticMesh(Cyl);
		SMC->SetMobility(EComponentMobility::Movable);
		SMC->ForwardAxis = ESplineMeshAxis::Z;
		SMC->AttachTo(SplineComponent);
		FVector Start, StartTang, End, EndTang;
		SplineComponent->GetLocalLocationAndTangentAtSplinePoint(i, Start, StartTang);
		SplineComponent->GetLocalLocationAndTangentAtSplinePoint(i+1, End, EndTang);
		if (!Start.ContainsNaN() && !StartTang.ContainsNaN() && !End.ContainsNaN() && !EndTang.ContainsNaN())
		{
			SMC->SetStartAndEnd(Start, StartTang, End, EndTang);
		}
	}
}

The break is pointing to

bool UWorld::AreActorsInitialized() const
{
	return PersistentLevel && PersistentLevel->Actors.Num() && bActorsInitialized;
}

In World.cpp

And the errors in the output I get is:

'UE4Editor.exe' (Win32): Loaded 'C:\Windows\System32\mswsock.dll'. Cannot find or open the PDB file.
'UE4Editor.exe' (Win32): Loaded 'D:\Projects\MobileApps\BallGame\Binaries\Win64\UE4Editor-BallGame.dll'. Symbols loaded.
First-chance exception at 0x00007FF984454F40 (UE4Editor-Engine.dll) in UE4Editor.exe: 0xC0000005: Access violation reading location 0x0000000000000068.
Unhandled exception at 0x00007FF984454F40 (UE4Editor-Engine.dll) in UE4Editor.exe: 0xC0000005: Access violation reading location 0x0000000000000068.

But I have no clue what that has to do with anything…

Anyone who has an idea?

2

I found the problem, The line that causes the problem should be executed in an OnConstruction function. But this works slightly different then the construction script in blueprints (These refresh when moving the object and OnConstruction only on placing or changing variables)

Blueprint construction works a bit better so I switched to that.