4.6 Transition Guide

Development Programming & Scripting C++
22

Great to hear from you all!

:slight_smile:

:slight_smile:

:slight_smile:

Wherever you currently have



GENERATED_UCLASS_BODY()

you will want to replace it with



GENERATED_BODY()

So if you have a pure C++ class then no change is required!

:slight_smile:

23

RHI Feature Level



GetMaxRHIFeatureLevel( )

is now



GMaxRHIFeatureLevel
24

Honestly, this should be an official page. Dear Epic, please hire already. This board is going no where without him.

Thanks a ton for all your works man, following your guide step by step atm. Will report if I found any other error.

25

edit: Never mind, I forgot to update my shortcuts and open the project with the old 4.5 exe. Everything seems to work nicely now.

26

Moved my question to the answerhub: Bad name index (unknown exception) - Programming & Scripting - Epic Developer Community Forums

27
  • thanks so much for this guide. It’s super helpful and much appreciated.
28

If you were using slate at all in your previous project, expect a lot of errors now.

You’ll need to change:


#include "Slate.h"

to


#include "SlateBasics.h"

You’ll then get a whole bunch of other errors about how some classes aren’t being used properly. In the end i just removed slate entirely and i’m rebuilding my UI from UMG.

29

Anyone having problems with TMap? My project worked fine in the previous version but in 4.6 it crashes inexplicably…

Any assistance greatly appreciated.

Consider this post a “I think TMap has changed” :stuck_out_tongue:

30

I replied to your answer hub :slight_smile:

You’re welcome !

:slight_smile:

31

BlueprintImplementable Const Reference

In 4.6 I have to change this



virtual void BP_Event_SolusFootStepOccurred(FVector Location,TEnumAsByte<EPhysicalSurface> SurfaceType);

to this



virtual void BP_Event_SolusFootStepOccurred(FVector Location,**const **TEnumAsByte<EPhysicalSurface>**&** SurfaceType);

or it will not compile

I seem to recall a time when I could pass TEnumAsByte by value to a BP implementable event, but not any more.

It gives a very vague compile error now, saying the function “was not found”

So if you have any issues with this, try using const reference!

32

Er, or just pass the enum directly by value:


virtual void BP_Event_SolusFootStepOccurred(FVector Location, EPhysicalSurface SurfaceType);

TEnumAsByte is a storage construct. Its main use is to restrict size of an enum to a single byte, making the managed code able to predict the size of a stored enum as it otherwise varies by compiler.

You also get type safety as an added bonus, but if you care for that you really should be using either the namespace enum idiom or an enum class.

33

Yup that does work too!

For consistency with the code base I tend to use TEnumAsByte since it is required for UPROPERTY()

34

it is not required anymore if you use the new recommended way of declaring enums, which is the c++11 good style.

ie use enum class

35

Did the upgrade from 4.5.1 to 4.6 in the office today. This guide was handy, thanks!

36

oooooh thanks for that info!

I updated my Enum wiki accordingly.

EDIT: oh wooow, I’m loving the new C++11 enum, so much easier to work with :slight_smile:



[QUOTE=ambershee;191257]
Did the upgrade from 4.5.1 to 4.6  in the office today. This guide was handy, thanks!
[/QUOTE]


Great to hear from you Ambershee!

:)
37

Hi all, thank you **** for your efforts, very useful thread !

I too have problems with updating my project to 4.6,
I managed to fix everything else pretty fast, except that I can’t seem to spawn a blueprint.
I asked a question on answer hub last week:
I spent some more time on that and made several tests including struct FConstructorStatics way,
no luck so far, even if it compiled it didn’t work in the game.
Anyway I feel I’m getting close, will try to figure it out soon as I’ll have time.

Jurij

38

Talking about the new enum style.

How do you compare or use enum (like for a array index) without casting? It was transparent in the old way, but not with the new way.
ex: MyArray[MyEnumValue], now you have to do: MyArray(int32)MyEnumValue].
you can’t do that also : GetDisplayNameText(EnumValue). you must cast.

More how do you get the enum from a number?

Did I miss something?
Thanks,

Thanks,

39

It was transparent in the old way
[/QUOTE]

Nor should it ever have been. C style enums are not type safe, and implicit conversions thereof have been a recurrent source of errors. People have come up with workarounds like namespace enums to try and guarantee some sort of type safety, but it’s still imperfect because of those implicit conversions.

Just static_cast to/from enum class, it spells out what you mean to do and helps make sure you’re not implicitly casting the wrong thing by accident.

40

I replied to your Answerhub :slight_smile:

41

now you have to do: MyArray(int32)MyEnumValue].
you can’t do that also : GetDisplayNameText(EnumValue). you must cast.

More how do you get the enum from a number?

[/QUOTE]

If you are going to do that you should definitely use



MyArray**uint8**(MyEnumValue)]

Because the enum is really a byte as you can see :



UENUM(BlueprintType)		//"BlueprintType" to expose to Blueprints
enum class EVictoryEnum : **uint8**
{
        VE_Dance 	UMETA(DisplayName="Dance"),
        VE_Rain 	UMETA(DisplayName="Rain"),
	VE_Song	UMETA(DisplayName="Song")
};

It is of course not entirely recommended way of doing things, but int32 is simply out of the question under any circumstances :slight_smile:


G**etting Value**

You mentioned wanting to get an exact value of an enum, you can get exact value even like this if you want!



```


SCREENMSG2("bytecast", **uint8**(EVictoryKeyModifiers::Shift));


```



Again, I am not suggesting this is an ideal way to do things, I'm just answering the question :)

Enjoy!