[ARTICLE] Explanation on how I used GameSparks Matchmaking and AWS Dedicated Server

[ryanjon2040]

@Muzaheed;622740

@ryanjon2040, do that technique works on both side of host server and client ?

Yes.

@Muzaheed;622740

where did u keep your code for game spark’s BlueprintAssignable(listener and game spark component both have these events) events ?

In my custom Game Instance class.

@Muzaheed;622740

but on client side whenever client join to a session and a new world gets loaded then the GameMode and actor both get deleted. so i lose all my data stored in there and also the code.

Game Mode doesn’t exist on clients. If you try to cast your game mode in client it will always return null. If you want data throughout the entire game (i.e: even after loading new level) you need to save your data inside Game Instance because they exist till you exit the game completely.

[Muzaheed (ahsan Muzaheed)]

i have tried your code sample.
sadly in 4.11, whenever a new level was loading the UGameSparksComponent stored in UMyCustomGameInstance was getting delated. and a new one was created by new AExampleGameMode() and was stored in UMyCustomGameInstance .
and i dont want that.
may be it works differently in latest version of ue4.

@ryanjon2040, do that technique works on both side of host server and client ?

no idea. how the UGameSparksComponent was getting survived on client side during joining to server.
from my knowledge ,all sceneComponent supposed to be getting collected by garbage collector.
hence no sceneComponent can survive on client side.
and sadly UGameSparksComponent is a sceneComponent .

i dediced to modify the GameSparks plugin as it’s source code available. and i hope i will be able to make it bypass garbage collection.

anyway thanks for all the answers

[ryanjon2040]

@Muzaheed;623068

i have tried your code sample.
sadly in 4.11, whenever a new level was loading the UGameSparksComponent stored in UMyCustomGameInstance was getting delated. and a new one was created by new AExampleGameMode() and was stored in UMyCustomGameInstance .
and i dont want that.
may be it works differently in latest version of ue4.

no idea. how the UGameSparksComponent was getting survived on client side during joining to server.
from my knowledge ,all sceneComponent supposed to be getting collected by garbage collector.
hence no sceneComponent can survive on client side.
and sadly UGameSparksComponent is a sceneComponent .

i dediced to modify the GameSparks plugin as it’s source code available. and i hope i will be able to make it bypass garbage collection.

anyway thanks for all the answers

For the GameSparksComponent in your GameInstance class, did you mark it as UPROPERTY()?

like this for example:

UPROPERTY()
UGameSparksComponent* GameSparksComponent;

[Muzaheed (ahsan Muzaheed)]

@ryanjon2040;623085

For the GameSparksComponent in your GameInstance class, did you mark it as UPROPERTY()?

like this for example:

UPROPERTY()
UGameSparksComponent* GameSparksComponent;

yes.

here in the video i showed what is happening with that sample code.

[video]https://youtu.be/5M16p-X8LyM[/video]

I also have attached the source code of gamemmode , game instance and modefied version of my UGameSparksComponent.

basically , to detect if existing UGameSparksComponent is a new one or previous one , i have added this variable in it :

const float aaaa = FMath::FRandRange(0.00, 99993.9999);

and then in UMyCustomGameInstance i was continuously printing the UGameSparksComponent stored in UMyCustomGameInstance 's
UGameSparksComponent* GameSparksComponent pointer.

in the video u will see that after hosting the GameSparksComponent gets cleared by garbage collector and set to null.

anyway, i have figure out a solution by modifying the gamespark plugin. most probably i will send them a pull request too.

[ryanjon2040]

If you dont want GameSparksComponent getting garbage collected then you should remove UPROPERTY() from it. If you look at my code example above you can see I never added UPROPERTY() for GameSparksComponent in GameInstance class.

Change from this:

UPROPERTY()
UGameSparksComponent* GameSparksComponent;

to this:

UGameSparksComponent* GameSparksComponent;

See attachment also.

[Muzaheed (ahsan Muzaheed)]

If you dont want GameSparksComponent getting garbage collected then you should remove UPROPERTY() from it.

actually i was given the opposite concept.
i added that UPROPERTY based on this line:
https://wiki.unrealengine.com/UPROPERTY

"Garbage Collection

Any Object that has at least one valid pointer stored inside a UPROPERTY will not be Garbage Collected (GC)."

Also i was informed:

"All components get garbage collected at some point. The UPROPERTY dec means that pointer adds a reference count to the object it points at. Without the UPROPERTY a reference isn’t added, so the object may be garbage collected at some points making the pointer invalid.

"

Game Instance persists throughout the entire play session, IIRC, while a game mode will pretty much only be active during one particular level.
Also, IIRC UPROPERTY being there doesn’t effect GC of UObject types other than letting the GC know that you’re referencing the object.
So while the GC may not collect the UObject, it’s not because the UPROPERTY was removed.

If you’ve got a pointer to a UObject type (anything prefixed with U or A in UE4), you need to put UPROPERTY above it. If you dont, it can be GC at any point. There are some exceptions- but you would know if those exceptions apply to your type.

UPROPERTY simply marks the pointer as a reference within the garbage collection system, which cleans up any un-referenced memory (to put it simply).
What ryanjon2040 probably meant is that if you want to manage the pointer directly, without it being tracked by GC, then you can remove the UPROPERTY macro. That isn’t the case though.
Unreal Property System (Reflection) - Unreal Engine
https://i.gyazo.com/d38227298ff62d256eaddeb7d92e731f.png

still i did the test after removing UPROPERTY .
now it is crashing while checking.
Bcz it is now null.
strange part is that it is not giving true for (if (GameSparksComponent == nullptr))
No idea.why

[delVhar]

Thanks for this, it’s incredibly relevant to me, and I’ll probably have some questions for you soon.

How have you handled horizontal scaling in your AWS instance with regards to talking back to Gamesparks? Was there much work required or was it “automagic” based on your AWS setup?

[Muzaheed (ahsan Muzaheed)]

@delVhar;626939

Thanks for this, it’s incredibly relevant to me, and I’ll probably have some questions for you soon.

How have you handled horizontal scaling in your AWS instance with regards to talking back to Gamesparks? Was there much work required or was it “automagic” based on your AWS setup?

u have to do it by yourself. there are some open source tools for it.
the only thing in this matter GS helps is that it can provide u how many player is playing on each server. also GS can help u by providing player geographical location.

[rajpootathar]

bump + following. I have been trying to find solution its almost been 2 weeks now.

[anonymous_user_233758bf]

are there any video tutorials for this out there yet?
the community would thrive from some solid videos on this subject