Reworking Cover - limitations and possibilities

[Zybertryx]

Greets,

 

I've been thinking about the problem of the cover bonus constants and how, at around 65 Aim, it's pretty well implemented, but when aim climbs higher cover becomes more and more meaningless. The really counter-intuitive thing regarding this though is that when in full view without cover (flanking) only the Aim of the attacker matters. And in those situations it never feels like enough. In the early game, cover works for both sides quite well (to due modest aim values) but when you leap off a roof 5 tiles away from an unobstructed Sectoid to get a flanking shot only to read "68%" - and then to miss - then eyebrows are rightly raised.

 

There's been talk here about how shoddy XCOM soldiers are regarding their marksmanship. Increasing Aim cures the flanking issue but renders cover more and more flavourless. I've thought of a great solution, though I'm not sure it's possible; the way the Squadsight Aim Penalty modlet works had me wondering if a similar post-native code function interjection could work to make cover more important.

 

What I think would make the tactical game much better is if a flanking shot earned the attacker +20 Aim. This would need to be balanced by keeping the base Aim of both aliens - and especially XCOM - relatively low through the game compared to Vanilla's superhero creep.

 

65 Aim vs target in High Cover = 25% chance. ( minus 40)

65 Aim vs target in Low Cover = 45% chance. (minus 20)

65 Aim vs Flanked target = 85% chance. (plus 20)

 

These would then be adjusted for range as normal.

 

That would solve the issue perfectly, no?

 

Balance wise it would warrant nerfing the Aim Bonus per level to avoid 100+ base Aim end-game toons (I think base Aim of 80 - 85 should be the upper limit). Starting Aim could even be reduced to 60. It would also make scopes and aim enhancing perks like Executioner much more useful. (Executioner feels a little superfluous on superhero snipers with scopes as is).

 

For those who want more realism from the tactical game, with cover being ever significant and with much more emphasis on positioning, range and flanking, this would be a great solution.

 

Thoughts?

 

And, can it be done?

Edited July 8, 2013 by Zybertryx

[Amineri]

I'll not try and weigh in on whether it would be balanced or not. I suspect that some people will like it and some won't, which is perfectly fine by me.

 

The easy part is adding +20 aim if the unit being fired at is exposed or flanked. This can be done quite easily in Adjust To Hit.

 

With the existing UI mod from the squadsight penalty mod, this to-hit adjustment should be reflected in most places in the UI. The targeting reticle, the icon number, the small tactical HUD info window, and the total to-hit chance displayed in the large tactical HUD info window (the "German Mode shot info" window, as it's refered to in-game).

 

So what is the hard part?

 

1) Adding in a new "exposed / flanked" to-hit bonus line in the large tactical HUD info window. Would basically have to add some code similar to how the Squadsight mod did it.

 

2) The really hard part : making the AI aware of the changes in the to-hit function. The squadsight mod doesn't really affect the AI much because the AI doesn't use squadsight for many troops. The to-hit penalties from the squadsight mod would affect the aliens, but the AI doesn't have to plan around it because the units don't have the ability.

 

First off, the AI retrieves the to-hit values directly, not using the UI functions (no reason to), so the first mod required is to make sure that the AI even is getting the correct to-hit values when assessing its priorities.

 

Changing the basic to-hit values for units that are exposed / flanked means that blowing cover / flanking becomes much more important, which means the AI would need to be adjusted to place greater emphasis on tactics the destroy cover or flank enemies, or it will become increasinly ineffective. Adjusting the tactics of the AI is going to be the really tricky part, I think.

[Bertilsson]

Is it possible to modify the defense-value of cover?

If modifying it to 40/60 and changing all units defense -20 or aim +20 in dfg.ini I think it would be the same result?

 

With the side effect that reaction shots suddenly became easier to hit... so perhaps a little nerfing to them would be needed in either case?

[Zybertryx]

As far as I know it's not possible to change the base cover values. I guess as my suggestion above is at least possible, it would be doable in a similar way, but it would require three changes (low, high, flank), with three more changes to the AI and UI etc rather than just the one I'm suggesting here (flank).

 

I wrote a wall (which anticipates your comment) as I'm utterly convinced this is the way to go.

 

 

 

Oh joy, I'm chuffed to hear that adding the +20 Aim bonus for flanking is the easy part!

 

Just to make the point more clear, the intention isn't really to make flanking easier/better, it's to make cover more significant. It's to make the game harder but smarter. By lowering the base Aim from say 60 (rookie) to 80ish (colonel - 85 for snipers or so - or even less, would need some playtesting) then high cover would always be an issue and low cover would likewise remain credible. If one simply overhauls the Aim values for XCOM and the aliens currently then yes cover becomes more significant, but flanking becomes an eye-roller joke too. I'm thinking primarily about how easily my high end toons kill aliens in low and even high cover and how rage inducing being killed by a solitary low end alien while in high cover is too.

 

As for the AI, I didn't really think too much about that as being a problem, although now that you mention it, I agree it would be helpful. Would also create the potential for fewer, smarter aliens on maps to remain a challenge for even high level 6 man XCOM squads. More aliens per map (given the limited size of the majority of the maps) is a crude solution to keeping the game challenging - a necessary evil for us all currently.

 

I'd be curious to try out the +20 Aim for flanking thing in isolation to see how it plays though.

 

In experimenting with giving aliens radically high mobility or radically high hit points I discovered that they behave differently anyway. Those with high mobility really do become aggressive flankers (because they already know that flanking is better and they have a wider range of good positioning options) and those with high hit-points become reckless killing machines (often even ignoring cover or overwatch altogether for a better shot). So, because the AI already knows that a flanking shot is preferable to any other shot, much of the "tricky part" is already covered or might only need a small tweak in 'weighting'.

 

I think now you're absolutely right that they'd need to know it adds +20 Aim to ensure they take that into account when deciding whether to stay put or to move for a better shot though, but that's all I think they'd need; just to know about it. As for greater emphasis on blowing cover and so on, alien plasma can again be made volatile and destructive, their misses would ruin the environment thereby exposing your braves and dynamically changing the battlefield (encouraging movement, even tactical retreats).

 

Having the UI update for the player would also be nice and would polish the change but is the least of the three factors imo. You imply that much of it, excepting a flank specific entry on the ingame "More info" (F1) screen, might already be compatible for those running the Squadsight modlet. Awesome.

 

I know you didn't want to weigh in on balance, I wrote all of the above to lay out my reasoning and motive more fully for any others reading and to hopefully get the seed planted! I see no negatives and a world of positives by doing this. It would be similar to making High Cover minus 60 and Low Cover minus 30 given the high aim per level trends of our mods (which largely solves the low end flanking silliness but makes the current 40/20 cover bonus pretty trivial late game).

 

Edited July 8, 2013 by Zybertryx

[Zybertryx]

An update for those interested.

The modlet is live and operational but, as it firstly requires a particular implementation of the SquadSight Aim Penalty modlet to be spliced in, I'm not yet going to cough up the Hex in a find/replace manner (it's too my.upk specific atm). I'll try to get a more generic version happening (I guess I could zero the Squadsight Penalty and give a complete replace of the entire function for those who want a Squadsight Penalty free variant) and maybe even a Long War 1.9 or latest Merciless compatible offering.

Alien Head Icon and Small Window Aim indicator are updating, no "F1" Menu entry yet. Looks to be problematic. DGC Aim values rebalanced accordingly.

Already feels intuitively satisfying. The very worst XCOM soldiers (as well as day one Sectoids) are now very dangerous things when the conditions are favorable (when flanking or shooting at exposed targets). Base Aim nerfed to both improve the significance of cover long term and to moderate the flanking/exposed buff (to avoid 100+% shots when unaided by extreme proximity, painters, scopes and/or Colonel level Aim values), end-game stat trends nerfed in kind. It's much more the perks and equipment that separate the men from the boys now.

Bertilsson correctly anticipated reaction fire shots becoming a little severe with these changes (and I worried that Oppourtunist would become ridiculously murderous). I'm happy to announce that the Aim buff is firstly easily alterable (2C ## style) and secondly that it now only applies to flanking shots and shots at exposed standing targets. If it's not a reaction shot and it is a flanking shot or an attack against an exposed target then the attacker receives the bonus Aim to that shot. Under all other conditions it will play as normal.

Musing AI priority tweaks (for flanking) but still seeing how it plays out in isolation for now. Closed beta. I can say with conviction that there's no going back from this for me now, this is the definitive XCOM! This is the latest addition to a thorough overhaul I've been working on for a while (and my first working attempt at proper rescripting rather than mere integer replacement or swapping entire functions for functions ripped shamelessly from your own mod packages).

 

I used to be a tabletop wargamer. . . my credentials. Necromunda ftw. :ermm: :geek: :biggrin: :devil:

The logic:

^^^^^^^^ SquadSightStuff ^^^^^^^^^

if(!IsReactionShot())
{
if(GetPrimaryTarget().IsFlankedBy(m_kUnit))
{
iAdjustedHitChance += 15;
}
if(!GetPrimaryTarget().IsInCover())
{
iAdjustedHitChance += 15;
}
}
}
else
{
iAdjustedHitChance = iHitChance;
}

I'm settled so far on a stronger global aim nerf with a Flanking/Exposed bonus of 15%, seems to look better when considering the timescale and aim trends of the game long term.

 

See for yourself:

 

 

Sectoids/Floaters/Worst Rolled Rookies

60 Aim vs Target in Low Cover = 40% Chance to Hit (minus 20)

60 Aim vs Target in High Cover = 20% Chance to Hit (minus 40)

60 Aim when Flanking Target = 75% Chance to Hit (Plus 15)

60 Aim vs Exposed Target = 75% Chance to Hit (Plus 15)

Thinmen/Early Ranks XCOM

65 Aim vs Target in Low Cover = 45% Chance to Hit (minus 20)

65 Aim vs Target in High Cover = 25% Chance to Hit (minus 40)

65 Aim when Flanking Target = 80% Chance to Hit (Plus 15)

65 Aim vs Exposed Target = 80% Chance to Hit (Plus 15)

up to Outsiders/Heavy Floaters/Mutons/Etherials/Cyberdics/Sectopods/Muton Elites/End Game XCOM'ers

80 Aim vs Target in Low Cover = 60% Chance to Hit (minus 20)

80 Aim vs Target in High Cover = 40% Chance to Hit (minus 40)

80 Aim when Flanking Target = 95% Chance to Hit (Plus 15)

80 Aim vs Exposed Target = 95% Chance to Hit (Plus 15)

Special thanks to johnnylump for being so approachable, for advice, good cheer and the inspiration to get into this in earnest (Long War), and especially to Amineri for her extreme patience, tolerance of my eclectic and nooblish queries, and for what has turned out to be a dizzying crash course in HEX subtleties, technics and basic scripting (ongoing I hope). Kudos to Eliot (!), Bertilsson and Bokauk for the essential tools.

Should give a shout out to Yzax as well, my first encounter with Merciless blew me away. From reading your various queries and wishes on the boards it seems you and I are of like mind on a great many things. This whole cover mechanic thing being foremost among them (and Ballistics with built-in suppression fire!)

Oh, and thank you Firaxis for no map editor and no multiplayer mod support and only 5 multiplayer maps (and the crappy ones at that) and for no single player mod support and for working on an XCOM FPS instead of releasing a damn map editor (even as a $$ DLC offer) but most especially [/bittervet] for this absolute gem of a game!

Z