GEngine - GetWorld() return NULL?

Development Programming & Scripting
1

How to get Real World pointer ?
This return NULL >>

UWorld* wp = GEngine->GetWorld();
2

Every class derived from AActor can use GetWorld() to access the World it is currently spawned in:

including APlayerController, AHUD, AGameMode, AGameState, and so on.

You can call GetWorld() in UGameViewport to get the World it’s related to at the moment, you can call GetWorld() in UGameInstance.

I think it’s enough to not worry about getting it in whatever place you need. I can’t check now, but as I remember GEngine is a static, to also get a GetWorld(), so you are doing it correctly.

The only thing that comes to my mind when considering your problem, is the place you invoke your GetWorld() in. Isn’t it a constructor of some class? Try to do it in BeginPlay() overridden method.

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3

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "Kismet/BlueprintFunctionLibrary.h"
#include "my_Center_Mouse.generated.h"

/**
 * 
 */
UCLASS()
class MYPROJECT_API Umy_Center_Mouse : public UBlueprintFunctionLibrary
{
	GENERATED_BODY()
	
	
	public:

	UFUNCTION(BlueprintCallable, Category = "111")
	static void my_Center_Mouse();
	
};
4

// Fill out your copyright notice in the Description page of Project Settings.

#include "MyProject.h"
#include "my_Center_Mouse.h"


void Umy_Center_Mouse::my_Center_Mouse()
{
	UWorld* wp = GEngine->GetWorld();

	if( !wp )
	{
		GEngine->AddOnScreenDebugMessage(-1, 15.0f, FColor::Yellow, TEXT("GEngine->GetWorld() return NULL"));
		return;
	}
	
	APlayerController* pc = GEngine->GetWorld()->GetFirstPlayerController();
	FViewport* vp = pc->GetLocalPlayer()->ViewportClient->Viewport;

	FIntPoint scrRes = GEngine->GameUserSettings->GetScreenResolution();
	vp->SetMouse(scrRes.X / 2, scrRes.Y / 2);
}
1 Like
5

Thank You for reply - but how me get this Real world PTR during extending UBlueprintFunctionLibrary…

6

Every UObject has the GetWorld() function, however it is not implemented for all of them since for most it doesn’t make sense. GEngine is a UEngine object, which is a static object that persists from game start to game end. During it’s lifetime multiple different worlds can be loaded, so it can’t return specific world to you. Since you have a blueprint function library you want to use a world context object to get the current world, which can look like this:

UFUNCTION(BlueprintCallable, Category = Misc, meta = (WorldContext = WorldContextObject))
		static bool RandomFunc(UObject * WorldContextObject);

.Cpp:

UWorld * World = GEngine->GetWorldFromContextObject(WorldContextObject);
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7

See Fluppi393’s answer.

8

Well explained, sir.

9

Okay - then be better use in bluePrints - Get Player Controller( 0 )
which return APlayerController*… from them can execute target code…

I thinked already has Static Function in C++ to do this without BP…
Someone CALLBACK function or something else…

Some information understand - need better investigate UE4…

10

UGameplayStatics::GetPlayerController also needs a world context object :wink:
If you declare the function like I wrote before, the WorldContextObject will automatically be assigned in blueprints and you don’t see it as a node.

11

If you want GetWorld() at UObject, Use this code

void UserWidget::TempFunc()
{
UObject* NewObj = NewObject(this); // use outer as a userwidget
}

3 Likes