Crash in Editor using a custom HUD derived Blueprint

Development Programming & Scripting Blueprint
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1

When basing a Blueprint on a custom HUD-Class like the one in A new, community-hosted Unreal Engine Wiki - Announcements - Unreal Engine Forums the Editor crashes when trying to enter the Blueprint-Editor.

Access violation - code c0000005 (first/second chance not available)

UE4Editor_MyProject8_8245!AMainMenuHUD::PostInitializeComponents() + 456 bytes [c:\users\clemens\documents\unreal projects\myproject8\source\myproject8\mainmenuhud.cpp:19]
UE4Editor_Engine!AActor::PostActorConstruction() …

2

Hello Thesbu,

I have a few questions for you that will help narrow down what issue it is that you are experiencing.

Quick questions:

  1. What version of the engine are you using?
  2. Can you reproduce this in a clean project?
  3. If so, could you provide a detailed set up steps to reproduce this issue on our end?
  4. Could you provide a screen shot of any blueprints that may be involved with this issue?
  5. Are you receiving any errors?
  6. If so, could you provide them?
3

Hi Rudy,

I. 4.7.2

II. Yes

III.I Create Code like in the linked Wiki-Tutorial and make it working (e.g. Set Game Mode)

III.II Create a new Blueprint based on the custom C+±HUD

III.III Try Editing the newly created Blueprint

III.IV Editor Crash while loading the Blueprint-Editor

IV. No Blueprints existing (Clean Project only with C+±Classes)

V. + VI. See End of original Posting

4

Hello Thesbu,

I followed the tutorial that you were using and I was unable to reproduce the crash that you mentioned. Could you provide the code that was used for the blueprint that you are having issues with?

5

Hi Rudy,

 #include "MyProject11.h"
#include "MyHUD.h"
#include "SMyCompoundWidget.h"

AMyHUD::AMyHUD(const FObjectInitializer& ObjectInitializer) : Super(ObjectInitializer)
{
}

void AMyHUD::PostInitializeComponents()
{
	Super::PostInitializeComponents();

	SAssignNew(Widget, SMyCompoundWidget).MyHUD(this);
	if (GEngine->IsValidLowLevel())
	{	GEngine->GameViewport->AddViewportWidgetContent(SNew(SWeakWidget).PossiblyNullContent(Widget.ToSharedRef()));
	}	
}

As you can see the differences are only:

  • The Project Name

  • The ClassName for the HUD-Class + CompoundWidget-Class

  • The Name of the Widget-Variable in the Hud-Class

  • The Name of the Slate-Parameter

Nothing of that should make a real difference. The Code compiles and works.

If you would like me to provide something else, I will, but, as said, my Code is the same (only Names differ) as in the Tutorial. I made that sure a couple of times now.

6

Hi Rudy,
I now solved the Problem by including a null-Check for the GENIGNE-GameViewport:

void AMyHUD::PostInitializeComponents()
{
	Super::PostInitializeComponents();

	SAssignNew(Widget, SMyCompoundWidget).MyHUDl(this);
	if (GEngine->IsValidLowLevel())
	{
	  
		if (GEngine->GameViewport != nullptr)		
		{	GEngine->GameViewport->AddViewportWidgetContent(SNew(SWeakWidget).PossiblyNullContent(Widget.ToSharedRef()));
            }
	}
}

But there remains the Question, why you could not reproduce the Bug!

Maybe the Tutorial should be extended by null-checks for GEngine + GEngine->GameViewport.

7

Hello Thesbu,

I am using version 4.7.3 of the engine. This may have made the difference in this case. However, I am happy to hear that your issue has been resolved. I will be sure to make a suggestion to the docs team. Thank you for your time and information.

Make it a great day.