[v21.5 Ex] GC - Excessive Alien Reaction Fire

[kabill]

EDIT: I've updated this thread below with a 21.6 save and a possible explanation for what's going on.

EDIT 2: I think I've worked out the problem. See the final post below.

I'm reporting this even though I'm not 100% sure it's an issue (I'll continue to look out for it).

Aliens seem to take more reaction shots than should be possible on their turn. The game seems to treat them as having all their TUs even when they used them on the previous turn.

Most notable is after suppressing an alien. In theory, an alien who is suppressed at the beginning of their turn should have half their maximum TUs. This definitely seems to be the case in terms of the combat actions they take.

As such, if an alien which was suppressed does nothing on its turn, it should end the turn with no more than 50% TUs. With TU shot costs as they are, this should enable only a single reaction shot on the following turn. However, I have had aliens take multiple reaction shots the turn after being suppressed, which should be impossible.

I've also noticed this with alien movement, however. I've had low-level aliens move several tiles, and then on their following turn take reaction shots as if they had all their TUs remaining. This is less easy to confirm, because I can't be 100% sure that the move didn't leave them with enough TUs to make those shots anyway. But combined with the issue with suppression, it's made me wonder if there's a bug somewhere (like alien TUs refreshing at the end of their turn, or something?).

EDIT: Haven't noticed this so much today. Maybe I imagined it? Will keep tabs anyway.

Edited March 11, 2014 by kabill
Updated for Version 21.6

[Max_Caine]

kabill, this did happen before and it was supposed to be fixed but it may still be lurking in the code. Keep looking - it probably isn't your imagination. And thinking about it, this could be tested for in the quickbattle setup. I may just do that when I get home.

[kabill]

Cool - didn't realise that it had been an issue before. Pretty sure I saw some more instances of this playing yesterday; I'll possibly see about grabbing some save files at points where it's likely to happen. (e.g. after suppression).

EDIT: Suppression definitely doesn't stop aliens taking their maximum number of reaction shots the turn after they were suppressed. I had a save game all ready to demonstrate this, but sadly it's become corrupted or something and won't load

EDIT 2: Here's another save. It should load (at least, it did hen I tried it!):

https://dl.dropboxusercontent.com/u/32960771/Test%203.sav

Both the Harridan at the bottom of the map (near the Scimitar) and the Harridan at the top of the map (by the shot hedge) were suppressed by my soldiers on the previous turn. Both did not take actions on their turn. On my turn, now, you will find that both these Harridans can take multiple reaction shots, when they should only be able to take one.

When I was experimenting, it seems that if the alien does something on its turn when it's suppressed, it then doesn't get any reaction fire (which is how it should be). It's only if it doesn't do something that it gets it's full TUs worth of reaction fire. Thinking about it, the times I believe this has happened without suppression have all been occasions when the alien has not attacked on its previous turn. As if an alien which does not take an offensive action doesn't count as having used any TUs for reaction-fire purposes.

EDIT 3: Yeah, I think I can confirm that the issue is when an alien doesn't take any kind of offensive action. I just had a Sibellian run half way across the screen, only for it to take it's full number of reaction shots on my turn.

Edited March 4, 2014 by kabill

[kabill]

Re-reporting this for v21.6 exp.

Bug definitely applies to suppression. This save file will demonstrate:

https://dl.dropboxusercontent.com/u/32960771/Reaction%20Fire%20Bug.sav

There is a Casean guard at the bottom of the map (near where all the smoke is) which was suppressed at the beginning of its turn. When it acted, it moved three tiles from behind the water trough to its present position, and crouched. Moving a Xenonaut near to will eventually provoke it into firing. When I tested, I was close enough that it shot with burst fire, which should be impossible since it should have less than half its TUs remaining.

Having just loaded the save again, I might have a solution. The alien should have had 25 TUs at the beginning of its turn (50/2). It moved far enough to use 9-11 of these (three tiles; don't know if turning counts for aliens). So it has ~15 TUs left. When I tested just now, this time moving around outside of burst-reaction fire range, it made three shots. That's more than it should be able to take (it should be able to take one), but less than if it had full TUs (which would be four).

I'm wondering, then, whether the alien is gaining 50% of its TUs back at the end of its turn (when the suppression effect is removed?). That would give it enough TUs for multiple shots but not its maximum; it would also give it enough for burst-fire. It would also account for me having seen aliens take their maximum number of reaction shots after being suppressed: if it doesn't move it would be put up to full.

EDIT: Having written all the above, I note that it doesn't seem to apply if the alien actually shoots on the turn it is suppressed. I did a trial before where I moved to try and provoke reaction fire from an alien that had shot while suppressed and it did nothing.

EDIT 2: Have an example of the bug without suppression. Save file:

https://dl.dropboxusercontent.com/u/32960771/Another%20Test.sav

The Casean guard towards the left-hand side of the map moved into my sight range on its turn and did nothing else. On my turn, as an experiment, I moved my soldier around at long range. The alien took reaction shots as if it had all it's TUs.

To make sure it hadn't moved just a short enough distance to be able to do this anyway, I modded the game such that the alien plasma rifle was set to fire a snap shot for 10% TUs. Loading the game and running soldiers around at distance again, the alien took a total of 10 shots - as if it had all it's TUs.

Whatever's causing this, it seems to be somewhat inconsistent. When I tried a similar thing to the above on an earlier mission, I couldn't call any reaction shots. However, in that instance the alien had moved over a barrier rather than just making a normal move, and had moved further through my line of sight. Maybe the game isn't counting TUs used in certain circumstances, or something?

Edited March 8, 2014 by kabill

[StellarRat]

I thought there was something wrong with suppression! Looks like I'm not crazy.

[Skitso]

The new %TU shot cost is probably just taken from the suppressed unit's /50 TU value me guesses?

[Chris]

In the first save game you provided, the alien in question has 37 TU. Their max is 50. That suggests that the suppression TU penalty is not being applied correctly in some circumstances.

If you play the gc_editor version and press U, it opens an editor that lets you view the TU of any unit you click on. We'll look into it at your end, but it might help your hunt too.

[kabill]

EDIT: Apologies in advance for huge wall-of-text.

--

Tried some testing with the editor. Found the following:

--

EDIT: Image sucks, apparently. If you zoom in you can kind of see the arrow but the picture doesn't really show much, sadly.

--

That's a screenshot of the editor. I've added a red square when a Sebellian Guard was at the beginning of its turn. On its turn, it moved to where the red arrow is pointing. On the following turn, I checked on the editor and the Sebellian in question had 55 TUs (i.e. all of them). To confirm this wasn't a glitch in the editor, I moved an LMG-bearing soldier nearby to trigger reaction fire. The alien reacted with burst fire, strongly implying it had its full TUs as the editor suggested. (For clarity, there was no suppression involved here at all.)

I note that the alien in question moved into a position where it could reasonably have shot one if not two of my soldiers at fairly close range. There was no reason for it not to fire; the distance it had moved really should have left it enough for a snap shot. There seems, then, to be a link between alien passivity and this TU bug. For what it's worth, this accords with my in-game experience: where I've noticed the TU bug occurring is in situations when an alien has either done nothing or only moved (a short distance).

Further messing around with another alien nearby failed to provoke the same behaviour. I spent 5-10 turns moving soldiers around, suppressing the alien, moving into cover and so on. I fired on me every turn as much as it could, as I would expect if everything was working normally. It was a different kind of alien (it was a Sebellian non-com) and it was set to defensive (I'd accidentally moved it out of the UFO using the editor, I think!). In case that matters.

I might do some more playing around at some point, but from this quick test it seems like there's something, somewhere, that's bypassing or overriding the normal working of things.

--

EDIT: I've done more testing, and can more-or-less reproduce the issue. It seems to be related to whether an alien can see/detect an enemy unit at the beginning of its turn.

- If it can, the alien acts normally.

- If it can't, then it will move but not use any TUs. If by doing so it detects one of your soldiers, it still will not fire. At the beginning of the player turn, the alien has all it's TUs.

I found this by playing with the GC editor again. After engaging with two Sebellian guards, I thought I would pull out of LoS and see what happened. The aliens camped; I got vision on them and then moved out of sight. On the alien's next turn, they moved ~5-6 tiles each. Checking the editor, both had all their TUs. I scouted them again, and again they moved, this time moving into sight range of my soldiers. They moved a short enough distance that they could have shot, but didn't. Editor on my turn says full TUs. I move, get blasted by burst reaction fire.

Oddly, one of the aliens seemed to get stuck with an exceptionally low Initiative value. It was necessary for me to reduce a soldier's TUs almost down to 0 in order to call a reaction shot, while the other Sebellian attacked immediately. Don't know what was going on there or whether it's related.

I'm going to have one more go with this to confirm, but this seems to be the key. Thinking back, this explanation would fit all the examples of off TU usage that I can remember (but this might be selective memory at work!). I can also say, however, that I have had aliens attack without having seen me first, even moving to do so (such as coming around a corner). So there's some inconsistencies where things seem to work as intended. The above issue seems reproducible, though.

--

MORE EDITING: Have done more tests. Conclusion are:

- When an alien is moving without being able to see/detect an Xenonaut, they do not spent TUs.

- If an alien moves into sight range of a Xenonaut on its turn, it might either stop (and therefore have all of its TUs on the next player turn) or it might move away (which uses TUs as normal, *but only for the move away).

- If an alien is suppressed and cannot see a Xenonaut on its turn, it seems to retain all of its TUs minus any it uses for movement. So, for example, a 50 TU alien when suppressed will have 38 TUs on the following player turn after moving 4 tiles.

All this, and the points I make in the previous 'edit' section are entirely reproducible.

Edited March 11, 2014 by kabill

[StellarRat]

kabill - Fantastic debugging/testing work. You found three fairly major hidden problems!

"I can also say, however, that I have had aliens attack without having seen me first, even moving to do so (such as coming around a corner). So there's some inconsistencies where things seem to work as intended." - I can vouch for this one.

Edited March 11, 2014 by StellarRat

[Skitso]

Wow, great bug hunting! Hope this gets sorted out quickly!

[Chris]

Thanks for working out what the problem was. I'm discussing this with GJ now.

[TacticalDragon]

I had notice this one too, if you play the game for more than 30 hours you'll see that the alien's real threat ins in Xeno turn... they make tons of reaction shots (With really low Accuracy) even if they waste all of their TU. In turn sometimes aliens don't do nothing but keep their TU. Quiet passive for alien AI, at first sight I think that Devs change the mechanic of the game that game, its dangerous and looks dynamic.