UPROPERTY deleted after C++ Constructor in blueprint subclass

Development Programming & Scripting C++
1

I have a problem that I found a workaround for but I’m wondering if anyone can explain what happened and why.

I have a UPROPERTY UTextureRenderTarget2D* in my AHUD subclass in C++. I assigned it using NewObject() in the constructor, and draw it in DrawHUD(). The code looks roughly like this:


In MyHUD.h:
	UPROPERTY()
	UTextureRenderTarget2D* Minimap;

In MyHUD.cpp:
AMyHUD::AMyHUD(const FObjectInitializer& ObjectInitializer)
	: Super(ObjectInitializer)
{
	Minimap = NewObject<UTextureRenderTarget2D>();
	Minimap->CompressionSettings = TextureCompressionSettings::TC_EditorIcon;
	Minimap->LODGroup = TextureGroup::TEXTUREGROUP_UI;
	Minimap->InitAutoFormat(600, 600);
}

void AMyHUD::DrawHUD()
{
	if (Minimap != nullptr) {
		DrawTexture(Minimap, ...);
	}
}

This worked great until I subclassed my HUD with a blueprint. Everything in the blueprint worked except for the minimap. After putting in some print statements, I found that the Minimap texture was being created, but deleted as soon as the constructor finished, so when it got to DrawHUD() it was null and didn’t draw anything. I moved the call to NewObject() to BeginPlay() and now the blueprint works, but I’m very confused why my pointer marked as a UPROPERTY() was being deleted ONLY as a blueprint, but working fine in C++. Anyone happen to know what’s going on here?

2

You should never call NewObject inside a constructor, in fact I thought that would give you an error.

Try this instead:


Minimap = CreateDefaultSubobject< UTextureRenderTarget2D >(TEXT("MyMinimap"));