What do we know about the combat AI?

[JimTheDinosaur]

I've been doing some testing with the AI's weapon selection and came up with these results:

AI does check for weapon:

- when he's out of ammo for his current weapon.

AI doesn't check for weapon:

- at the start of combat or with a new turn (e.g. even if he's unarmed and has a bazooka in his pocket, he won't bother with it).

What weapon does he choose:

- NOT the type of weapon he's run out of bullets for (so if he has a second 10mm SMG's, he will ignore it if his current one runs out).
- he completely ignores range (yes, even if you're out of range of his preferred weapon), value, ap cost, mag size, burst amount, weapon art, attack modes. At least, he ignores weapon art and attack modes when it comes to weapons within his prefered category (i.e. smg or pistol art, burst or single shot modes are irrelevant, knife or pistol animation are relevant). All he looks at is:
- min and max damage, BUT NOT IN THE WAY YOU EXPECT. Unless I've tested this wrong (I deleted all of my mod's scripts to be safe when doing it), the formula for weapon selection seems to be something close to Max Dam - Min Dam. Yes, you've read that right, Max Dam MINUS Min Dam.

I honestly hope I've tested this wrong, but check it out for yourself: if you set all of a 10mm smg's stats to that of a 10mm pistol's, the AI selects the 10mm SMG. But if you drop the 10mm pistol's min dam by 3 (for some reason that bothers me not 1 or 2), then he selects the 10mm pistol, decrease the max dam of the pistol by 1 again, then he selects the smg, decrease the min dam by 1 and he selects the pistol, etc. etc.

@phobos2077, you told me you could tell exactly what the AI was "thinking" by looking at the code, just not how to change these workings script-wise, right? Could you maybe tell me if I'm right and tell some other things you found that are interesting? If we can't change AI behavior through hookscripts we could possibly find other ways around it (e.g. block undesirable movement though hs_aiblocking or whatever it was called).

As for how to override weapon selection, it's easy enough in the case of being out of ammo: the AI does a final AP cost check with his out of ammo weapon, so in that case you can set the max damage of the weapon you want him to pick to 1000, then reset it the next AP cost check with the new weapon. I'd suggest making weapon selection purely contingent on cash value as an easy "fix" (given that value ideally already incorporates factors such as AP cost, range, damage, mag size, etc.).


Edit: As for AI AP use, this is what I've come up with

Using chems/reloading weapon: 2 AP per reload/chem used.
Changing weapon: 0 AP.

Seems the AI likes to cheat

edit 2: Aha! while AP cost doesn't matter when replacing an empty weapon in abstract, it does matter when the AI is low on AP, then he only selects a weapon he can use that very same turn.

edit 3: seems hard to think of a way to make the AI play by the rules, as he's impervious to the override in hs_useobj(on)... tho he could still be charged extra AP's, maybe subtracting them from the next turn if he runs over or something

 

[CPL]

Another thing they always do (even with any tweaking to burst fire always) is switch a weapon that has explosive damage (for example: I changed shotgun type weapons to have explosive damage in my game for the spread effect and to blow certain doors of their hinges) to another one if their target is next to either you or the rest of your crew. If a gecko happens to be right on Sulik and Vic, armed with a shotgun, is about to shoot it after shooting whatever else, then he'll switch it. That sort of thing. Sometimes, that annoys the shit out of me because I want them to use it when there is a crowd there and that happens.

 

[JimTheDinosaur]

Tho I've only tested with enemy AI, not party member AI, I'd guess that also has to do with max/min damage; I didn't notice caliber having any impact on the decision making.

Also, it's actually much easier to change the AI's weapon, namely through simply forcing a wield in hs_apcost. But this is riskier than the aforementioned approach because if he doesn't like the weapon type (e.g. a knife where he wants a gun), he'll freeze up entirely...

edit: hmm, seems this doesn't have to do with him getting the weapon he expects, just that when he's out of ammo he expects to get another ranged weapon (I think)... at least, force equiping a knife when not having an out of ammo weapon works "fine" (except he refuses to use the weapon the first turn and instead punches... going the more subtle route of making the AI think it's making the decision itself might be best all in all).