Game crashes when I try to get surface type

Development World Creation
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1

I wrote a very ugly function to trace to the floor and get the surface type and play a footstep sound. The problem is that it crashes when I try assigning the surface type from the hit result to an EPhysicalSurface variable. Here’s the whole function:

void AAdNoctvmPlayerCharacter::DoFootstep()
{
	AAdNoctvmPlayerController* PC = Cast<AAdNoctvmPlayerController>(Controller);
	
	FCollisionQueryParams Params = FCollisionQueryParams(FName(TEXT("FootstepTrace")), true, this);
	FVector Start = GetActorLocation();
	FVector End = Start + FVector(0, 0, -100);
	FHitResult HitResult;
	
	bool bHit = GetWorld()->LineTraceSingle(HitResult, Start, End, ECollisionChannel::ECC_PhysicsBody, Params);
	
	if (PC)
	{
		if (bHit)
		{
			EPhysicalSurface Surf = HitResult.PhysMaterial->SurfaceType;
	
			if (Surf == EPhysicalSurface::SurfaceType_Default)
			{
				PC->ClientPlaySoundAtLocation(DefaultFootstep, GetActorLocation(), 1, 1);
				NoiseEmitter->MakeNoise(this, 1, GetActorLocation());
				GEngine->AddOnScreenDebugMessage(-1, 1.f, FColor::Yellow, TEXT("Played footstep sound"));
			}
			else if (Surf == EPhysicalSurface::SurfaceType1) // brick
			{
				PC->ClientPlaySoundAtLocation(DefaultFootstep, GetActorLocation(), 1, 1);
				NoiseEmitter->MakeNoise(this, 1, GetActorLocation());
				GEngine->AddOnScreenDebugMessage(-1, 1.f, FColor::Yellow, TEXT("Played footstep sound"));
			}
			else if (Surf == EPhysicalSurface::SurfaceType2) // cobblestone
			{
				PC->ClientPlaySoundAtLocation(DefaultFootstep, GetActorLocation(), 1, 1);
				NoiseEmitter->MakeNoise(this, 1, GetActorLocation());
				GEngine->AddOnScreenDebugMessage(-1, 1.f, FColor::Yellow, TEXT("Played footstep sound"));
			}
			else if (Surf == EPhysicalSurface::SurfaceType3) // glass
			{
				PC->ClientPlaySoundAtLocation(TileFootstep, GetActorLocation(), 1, 1);
				NoiseEmitter->MakeNoise(this, 1, GetActorLocation());
				GEngine->AddOnScreenDebugMessage(-1, 1.f, FColor::Yellow, TEXT("Played footstep sound"));
			}
			else if (Surf == EPhysicalSurface::SurfaceType4) // gravel
			{
				PC->ClientPlaySoundAtLocation(DefaultFootstep, GetActorLocation(), 1, 1);
				NoiseEmitter->MakeNoise(this, 1, GetActorLocation());
				GEngine->AddOnScreenDebugMessage(-1, 1.f, FColor::Yellow, TEXT("Played footstep sound"));
			}
			else if (Surf == EPhysicalSurface::SurfaceType5) // wood
			{
				PC->ClientPlaySoundAtLocation(WoodFootstep, GetActorLocation(), 1, 1);
				NoiseEmitter->MakeNoise(this, 1, GetActorLocation());
				GEngine->AddOnScreenDebugMessage(-1, 1.f, FColor::Yellow, TEXT("Played footstep sound"));
			}
			else
			{
				return; // don't make a sound
			}
		}
	}
}

This is the callstack: !Name:VibgyorAccess violation - code c0000005 (first/second chance not avail - Pastebin.com

The last line executed is EPhysicalSurface Surf = HitResult.PhysMaterial->SurfaceType;

Anyone know what’s wrong with my code?

2

You need to make sure HitResult.PhysMaterial is not null before accessing its data members. If its null then you can’t proceed with what you are doing after it.

3

Man, I’m stupid. That should have been obvious. Thanks!