Mutiple Articy Players Playing Same Flow

Mon 27. Jan 2020, 20:24

So for our NPC's we're handling our AI via Articy. We put an Aritcy Flow Player, an ArticyFlowHanlder script (ours, which handles the OnFlowPlayerPaused() and OnBranchesUpdated() callbacks), and a Behavior script on each NPC. The Behavor stuff is just a simple coroutine that does simple actions with random delays so that all NPC's won't look like they're doing the exact same thing at the same time.

The AI itself is a custom flow fragment, which contains input pins to multiple Behavior fragments that are chosen via global variables. One the Behavior fragment is reached, it calls the NPC's Behavior script to do it's thing. Once the behavior is done, the output pin points to a Jump, which jumps back to the AI fragment. Rince, repeat.

This worked fine when we only had one AI flow object being used at once. However, when we tried using the same AI flow fragment on multiple Articy Flow Player/ArticyFlowHandler objects, they began tripping over each other. It was like every time one of the AI fragments would get to the jump point, it would trigger every other NPC's flow player in the scene that was using the same AI flow fragment, even though they all had their own individual Players.

Is this expected behavior? IE if you have multiple flow players all using the same flow fragment, when the flow fragment changes it calls every single flow player that's referencing it? And if so, is there a way that we can specificy a specific Flow Player that's called from the flow fragment itself?
Thanks!
-Mike
MikeRifRaf
 
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Re: Mutiple Articy Players Playing Same Flow

Tue 28. Jan 2020, 09:36

Hi MikeRifRaf,

first i want to clear a potential misconception: when you say "using the same Flowfragment" it is more or less just reading it. Articy Objects in unity don't store any value for a specific flow player, they only contain data for their general flow structure. Any additional data necessary is stored on each individual flow player. That being said, i don't see any particular reason why 2 flow players should "trip" over each other but that doesn't mean there isn't an unknown bug.

It was like every time one of the AI fragments would get to the jump point, it would trigger every other NPC's flow player in the scene that was using the same AI flow fragment, even though they all had their own individual Players.


Once a single instance of a flow player is paused it only resumes with a direct call to Play() or indirectly (via StartOn) otherwise there should be no reason why it continues resuming. Especially i don't see any reason what could cause FlowPlayer A to let FlowPlayer B resume.

If you have more information regarding this issue let me know!

Best regards

Nico
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Re: Mutiple Articy Players Playing Same Flow

Tue 28. Jan 2020, 15:27

Hm...what you're describing is the behavior I was expecting. Let me do some more tests and I'll get back to you.
Thanks!
-Mike
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Re: Mutiple Articy Players Playing Same Flow

Tue 28. Jan 2020, 16:36

OK I ran some more thorough tests (with console output) and here's a more visual explanation of what's happening and the behavior I'm seeing. Hopefully I'm just missing something.

Our AI frags are just lonely custom Template frags hanging out in the project. I created one for the Crew of our ship.
Image

Inside each node is just a very simple setup:
Image

The purple node is what we call a Behavior. So each NPC has it's own ArticyFlowPlayer() script which is set to start on Crew AI and our own custom FlowHandler() that deals with the ArticyFlowPlayer callbacks for pauses and branches. Also, while it may seem like using an ArticyFlowPlayer() to handle this would be unnecessary, this is just a simplified version of what a normal AI frag is like. Normally, there's multiple purple Behavior nodes that have conditionals on their input pins, so what happens is that at the start of each loop the ArticyFlowPlayer() handles the conditions and tells us which of the nodes is valid via OnBranchesUpdated(). So what our code does is save the current pause object that was passed via OnFlowPlayerPaused(), then when OnBranchesUpdated() is called right afterwards we check the situation and if we're paused on a Behavior we start the Behavior code. The Behavior code is coroutine that takes the info from the Behavior and executes it with some random delays thrown in to make sure all NPC's don't act exactly alike. Once the coroutine done, it lets the FlowHandler() know that it's done and it proceeds to continue the flow, which is just to get to the jump, jump back to the AI, get to the Behavior, repeat.

I've added some print statements in our FlowHandler() code that lets us know when we're about to begin the Behavior code and when it ends. I added time stamps as well. Here's what happens when only one NPC (Grunfeld) is using this setup:
Image

So as you can see the Behavior starts, some time passes, the behavior ends and then it's restarted again very quickly (I think it's just three frames because we don't pause on connections or pins).

Now when I have the same AI frag on two NPC's, here's what happens:
Image

So what's happening is that Carver and Grunfeld star their Behaviors, Carvers ends, he gets his flow going again which causes a restart of the behavior, but when he does that Grunfeld's flow player is going again as well which causes his Behavior to start agiain before the previous one was done. His flow player should still be waiting for the callback from his own Behavior before continuing, but it's being continued after Carver restarts his (part of why I think this is what's happening is that the time stamp for both Carver and Grunfeld's 2nd start is the same. You'd expect it to be the same the first time but the 2nd time they should start at different times unless the randomizer happened to choose the exact same values, which would be rare since it's a random float). The error message is something I put in the code. I set a flag to true at the start of the Behavior coroutine and set it to false at the end, so in the FlowHandler() code if you're trying to start the Behavior again before it's finished it lets us know. So the error shows up before Grunfeld starts his Behavior again, which he shouldn't because his Behavior hasn't finished yet, only Carvers. If you stop and start the scene multiple times the error switches back between the two characters. This is the part what I think Grunfeld's flow player is getting restarted by Carver's flow player, which doesn't make sense because they each have their own flow player on their game object, but they share the same AI frag.

Now if I make a duplicate copy of the AI frag and have each NPC's ArticyFlowPlayer start on one of the two individual nodes (NPC Crew 1 and NPC Crew 2), you get this:
Image

This is the expected behavior in that each Behavior starts, runs, ends, and repeats all without the the Behaviors not starting until the previous Behavior finishes (note how the time stamps for every start after the first are different due to the random times involved with the Behaviors).

So this is pretty much a cleaner test of what I was encountering when I posted the original message about things tripping over each other. It's still very possible that I'm doing something wrong but I simplified the scene so that pretty much Carver and Grunfeld just running their AI loops is all that's going on. I hope this helps and makes sense! Let me know if you need any more info.
Thanks!
-Mike
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Re: Mutiple Articy Players Playing Same Flow

Fri 31. Jan 2020, 10:27

Hi MikeRifRaf,

first thank you for this detailed report, much appreciated and helpful indeed!
QA is going to test it and see if we can reproduce similar behavior. I will get back to you once i know more.

Best regards

Nico
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Re: Mutiple Articy Players Playing Same Flow

Mon 3. Feb 2020, 20:09

No problem at all! I just sincerely hope that it doesn't turn out to be a waste of your QA time because it was user error :D
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Re: Mutiple Articy Players Playing Same Flow

Tue 11. Feb 2020, 15:09

Hi MikeRifRaf,

Unfortunately, we were not able to reproduce this issue.
Is it possible that you send us a project (Unity + Articy) where the issue occurs?


Best regards,

Chris
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[Articy] Christian Schildt
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Re: Mutiple Articy Players Playing Same Flow

Wed 11. Mar 2020, 18:10

Hey there. Sorry it's been a while we got massively side tracked with mini game stuff. Once we're back to normal i'll see if my boss will allow me to whip up a small project with the issue and get it to ya asap.
Thanks!
-Mike
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