AI Development Guide and M27AI v81 Devlog

maudlin27

Latest changes (v56-57 summary)

New unit added - Stealth boat
10 Bug fixes, including a rare naval bug that meant naval units didnt move, gifted PGens not being returned to their owner, and a bug causing the ACU to not move (leading to M27's ACU chilling underwater in the last rainbow cup round while its base got torn to pieces nearby)
13 misc changes, including an expansion to dodging micro to work in an area (primarily to help naval units which for the AI end up stacking units ontop of each other making them highly vulnerable to any aoe), tweaks to queued torpedo bomber orders, and having naval factories build a greater variety of units at T3 (instead of only T3 units)

v57 update
I revisited the approach to pathfinding thanks to Jip detailing the appraoch used by Balthazar for determining pathability which was much more accurate than M27's approach (broadly, M27 was checking how much the height changed at 0.5 intervals to determine if you could path there, but counterintuitively you get a more accurate result if you check the distance every 1 block, i.e. less frequently). As the changes took far less time than I was expecting I figured I'd release ahead of the upcoming rainbow cup games (as it should hopefully reduce the risk of strange results and also slightly improve game speed).

maudlin27

v58 Update
This update was mostly about making changes from some prominent issues I noticed from the recent Rainbow Cup tournament casts, including:

On Dark Liver its ACU ignored lots of reclaim by it to advance on a land factory relatively far away. Meanwhile there was very noticeable stuttering when running the replay at increased speed
On Carrius it started a T3 pgen with almost no mass income and while mass stalling, and paused a land factory with a T3 mobile artillery 99% complete
On Air wars it was slow getting a transport and then sent it to the other side of the map
On Exo 50-T testing ground it eventually got a soulripper and suicided it into the enemy base when it didnt have air control
On Citadel M27 built a massive army of inties (more than 100) which often suffered heavy casualties when traveling over enemy flak
On one of the replays the casters commented on lack of variety in M27's taunts
I've also made some refinements to some other aspects noticed from pre-release testing replays.

Changes made

10 bug fixes, including one with transports causing them to try and target the furthest plateau from them instead of the closest (per the air wars replay)
34 misc changes, including:
ACU adjustments to make it more likely to run from large threats and reclaim in preference to attacking out of range units
Increased taunt variety
Ecoing enhancements, including assisting mex upgrades, not pausing near-complete factories, and having a basic mass limit before starting a T3 factory upgrade
Added caps on certain units (inties, gattling bots, hoplites)
Reduced pathing limit from 1024x1024 to 512x512 to improve stuttering at faster game speeds
Various adjustments to plateau logic so transports are built sooner and prioroitise nearby plateaus, while factories built at those plateaus should build units even if M27 is trying to eco
Adjustments to naval bombardment logic (so e.g. Aeon missile ships shouldnt waste their time firing at moving T1 tanks when the enemy base is nearby)

Acknowledgements

Fearghal for organising the Rainbow Cup tournament, and the casting team for providing an entertaining stream of it (in particular Endranii, Spikey Noob and Swokoll who casted M27's games)

tyne141

The latest updates seem to work well. I've had some good games on maps like Flooded Strip Mine when the AI navy seems to work pretty well. One weakness I found in recent games is that the AI is sending their commanders forward fairly far into the game and they're relatively poorly defended in general and definitely poorly defended against air. If you try to go air too early the AI seems to adapt and defend fairly well but if I don't go air at all early game and then when their commanders cross that map towards me, spam a whole lot of T1 bombers very quickly I can almost always snipe the commander/s. Other than that it's really challenging though as it is still beating us quite frequently with either nukes, artillery or experimentals. Here's an example replay of sniping the commanders with T1 bombers: https://replay.faforever.com/18219133

tyne141

Possible bug causing crash: hi there we just had a game crash and I am not sure if it was possible an AI bug with M27AI. The log has some lines that mention M27.

I've pasted a few of the lines below but I can sent the full log if you want:

EXCEPTION_ACCESS_VIOLATION (0xc0000005) at address 0x009272e4
attempted to write memory at 0x50895010

Program : C:\ProgramData\FAForever\bin\ForgedAlliance.exe
Cmd line arguments : /init init.lua /nobugreport /log C:\Users\tyne1\AppData\Roaming\Forged Alliance Forever\logs\game_18231596.log /gpgnet 127.0.0.1:22751 /mean 1149.82 /deviation 311.527 /savereplay gpgnet://127.0.0.1:51135/18231596/tyne141.SCFAreplay /country NZ /numgames 8 /numgames 6

Callstack:
Unknown symbol (address 0x009272e4)

Last 100 lines of log...

warning: [C]: in function assert' warning: [C]: in function pcall'
warning: ...nder forged alliance\mods\m27ai\lua\m27utilities.lua(79): in function ErrorHandler' warning: ...nder forged alliance\mods\m27ai\lua\m27utilities.lua(1023): in function GetACU'
warning: ...forged alliance\mods\m27ai\lua\ai\m27airoverseer.lua(6851): in function <...forged alliance\mods\m27ai\lua\ai\m27airoverseer.lua:6716>
info: Warning - no valid units in tNewUnits
info: Warning - no valid units in tNewUnits
info: Warning - no valid units in tNewUnits
warning: false\000M27ERROR Count=1: GameTime 1018: Cant find any ACUs that we own for brain2, and in assassination game mode, so will treat us as being defeated
warning: stack traceback:...

maudlin27

@tyne141 Have you got the replay ID? Those error messages are expected with M27 if an ACU has just died (and sometimes happen at the point a game is closed down), although it's still possible that M27 is connected to the crash

maudlin27

v59 - Gunships

Unlocked gunship usage for M27 and incorporated special micro logic to improve their survivability
Various changes aimed at slightly decreasing vulnerability to T1 bomber snipes
Improvements to logic for killing underwater ACUs
Various improvements to make M27 respond better to nearby enemy firebases (i.e. if the enemy gets a firebase in range of M27's core base)
8 other misc changes and 6 bugfixes, including improvements to M27's T1 bomber defence when faced with lightning tanks

Acknowledgements

Tyne141 – Replay highlighting ACU’s vulnerability to a T1 bomber snipe
Azraeelian Angel – lots of replays which prompted many of the changes this version (in particular the logic for killing underwater ACUs, better T3 MAA defence, and dealing with an enemy ACU that builds a firebase to kill M27’s core base)

maudlin27

v60 - Naval enhancements
The main focus was improvements to M27's naval logic:

Navy should now respond to torpedo bombers (Cruisers trying to attack them, other navy retreating)
Battleships can make use of ground fire in some scenarios to hit underwater targets
Naval response will be based on the size of the enemy threat - no longer should M27 send its entire fleet to intercept a single T1 engineer
7 other naval related chantes, including Seraphim sub hunters temporarily surfacing to fire at torpedo bombers
Improved skirmisher avoidance logic so they're a bit harder to kill with a guncom
6 bugfixes and 8 other misc changes, including rewriting weapon prioritisation logic to fix some scenarios where it wasn't working, and adjustments to gunship logic to increase their area of operations

Acknowledgements:

Relent0r noting M27 struggled against RNG on naval maps due to its tendency to chase down lone enemy units with its entire navy

maudlin27

v61 - Stats
A couple of significant changes in this update, neither of which has any impact on how M27 plays:

Added detailed stats profiling which can be accessed regardless of whether an M27 AI is playing in the game (i.e. the mod just needs to be enabled and the configuration option set in the code to enable the stats) - as featured in the recent AI tournament
Created a separate AI mod! (However this mod just uses the AI as a means of spawning ACUs for human players at different start points). It hopefully provides an extra option for people wanting to fight the AI where a single AI is too easy but multiple too hard (in addition to the more mainstream use for PVP games)

In terms of other changes (that will impact how M27 plays):

Added naval factory land defence logic (so enemy land units that try and attack the factory should no longer be ignored)
Implemented and then promptly removed IMAP functionality, and instead created my own 'M27 IMAP' logic to help strat bombers be less likely to choose a target that sends them into a cloud of enemy interceptors
Various improvements to naval logic (13 changes)
Various improvements to air logic, particularly focused on when M27 is behind on air (8 changes)
6 misc changes, including a greater focus on reclaim
15 bugfixes

Acknowledgements:

Thacon – replay highlighting M27’s vulnerability when the entire enemy team focuses solely on air.

maudlin27

Latest changes (v62 summary)
Introduced a new land rush mode for the AI which it will sometimes (but not always) use on smaller maps to favour t1 tank spam over its more conservative/ecoing approach.

During testing overall it feels marginally weaker for M27 than its normal approach, but it managed to pull off wins in some scenarios that the normal M27 would lose to.

Other changes:

Various changes meant to further improve M27's response when far behind on air along with other misc changes (11 changes to air), including significantly increasing production of both asfs and MAA, and being more cautious with use of asfs
4 Misc changes to naval logic, including adjusting the unit mix and focusing down mexes
6 bugfixes, and 13 other misc changes, including adjustments to early game building logic for the ACU and engineers and reducing ACU's tendency to dodge (which could lead them to taking more damage since they won't overcharge when dodging)

Acknowledgements

Azraeelian Angel - Several replays highlighting M27's vulnerability when losing air control (and the speed with which it needs to build SMD to stop humans)
RottenBanana - 1v1 replays highlighting M27's vulnerability to raids and a bug with trying to raid underwater mexes
Deribus - replay highlighting the delayed response to building TMD at a firebase when being attacked by TML

maudlin27

Latest changes (v63 summary)
Various changes based on replays received, including:

Less likely to overflow mass at T3 stage, with a significantly faster scaling up of build power (6 changes)
T3 fixed arti prioritisation coupled with target variation (to avoid firing at the same heavily shielded position forever) (9 changes)
Air less suicidal and also better at defending high value friendly air units (18 changes)
Chokepoint maps - M27 will now abandon a chokepoint and revert to default logic rather than staying in turtling mode if it's chokepoint is overrun and it somehow survives, along with several other small adjustments (3 changes)
SAM creep logic - Basic code to have M27 try and protect mexes with SAMs if it's behind on air
14 bugfixes and 19 misc changes

Acknowledgements

Radde - various replays, highlighting M27’s poor ability to cope with lots of mass, flaws with the turtle logic, and tendencies to suicide its air (including air experimentals).
Azraeelian Angel – Loads of team game replays (so many I had to defer analysing some of them for the next release!), highlighting amongst other issues the need for better T3 arti building logic
Spikey Noob – A number of 1v1s at increasing difficulties on badlands highlighting the ease with which M27's ACU can be killed with T1 land
Jip – 2v2 replay against M27
Relent0r – Flagging a bug in M27 that causes it to break default AI from building on mexes that are covered by reclaim.

maudlin27

Smaller update fixing a few bugs and adding in mass fabs:

Unlocked ability to build T2 mass fabs (I've not checked how it handles reaching the unit cap though, here's hoping it doesn't ctrl-K them!)

6 bugfixes, including

Bug resulting from the latest FAF patch that caused the Ythotha death ball/energy signature to be controlled by the AI (at the same time I've improved M27's response speed to the death ball from before)
Shield boats should no longer remain at the naval factory if they had lost shield at any point in the past
The Bjarg map should now be playable by M27 in the bottom-right start position (previously it would break)
14 Misc changes, including:
MML should be far less likely to walk into range of T2 PD
Added new 'experimental prioritisation' builder logic for late-game (where land factories are less likely to build units to conserve mass for experimentals)
Slight improvements to M27's response when an enemy tries to get a firebase near M27's base
Slight reduction in the bomber defence range to make them less likely to suicide into enemy air

Note that updates may be smaller and/or less frequent for a bit as I mull over creating an entirely new AI, and/or testing out changes in a basic alternative AI that might then be incorporated into M27 at some future point.

Acknowledgements

Jip – Highlighting error on the Bjarg map where if M27 started in the bottom right position it wouldn’t work
Azraeelian Angel - A number of team game replays
Radde - Several teamgame replays

maudlin27

Latest changes (v65 summary)
Smaller update - I'm experimenting with smaller ad hoc updates with reduced testing for fixing issues highlighted in replays (since I'm not planning any big future changes to M27 for the time being as I'm experimenting with a separate AI to try out alternative land based logic)

11 bugfixes, including:

Incorrectly calculating Seraphim SACU range as their TML range (leading to strange actions from land units)
Skirmisher platoons (e.g. sniperbots) should be less likely to suicide (by being more likely to attack move and less likely to try and move close to a target)
Experimental shots such as ythotha shots will now be considered for dodging

10 Misc changes, including:

Adjustments to skirmisher logic, including making them run further from T2 arti, and splitting up skirmishers that are far apart into separate platoons
Increased the value of SMD and Nukes as targets
Made larger units more likely to try and dodge shots (e.g. summits should try and dodge Aeon battleships, Galactic (colossii?) should try and dodge Ythothas)

Acknowledgements

Radde for providing an entertaining team game replay against M27 (that also highlighted some of the bugs fixed in this release).

maudlin27

Latest changes (v66 summary)

Refinements to the logic for experimentals to dodge shots (and more generally) so they're hopefully less likely to turn around in a full circle doing no damage while being attacked
7 tweaks to T3 arti targeting logic, none of which are major but which for example now assign a value to heavily shielded units (previously none was given), firing infront of mobile units, reducing the value of targets that we have fired a huge number of shots at without killing, and factoring in how long it will take for the T3 arti to turn towards the target
15 other misc changes or bugfixes, a number of which relate to decisions on when units should retreat (e.g. MML running from ravagers, skirmishers running from PD, GC/Monkey/Ythotha being more likely to run from a fatboy based on how close it is)

Acknowledgements:

Radde - several teamgame replays on both land and naval maps
Jip and Magge for highlighting a missing units error message that appeared a lot, and also Jip for helping me figure out how to determine which direction a T3 artillery is aiming at.

STlNG

Stop making it better. It's getting too hard to beat. I'm kidding. Your work is appreciated.

maudlin27

@stlng At some point! Each update lately I think just after uploading 'right, now I can take a break and focus on writing a new approach to handling land units', then I see a replay where M27 does some stupid or incorrect things and figure I'll just put through one more update to fix it!

Sioloc

Anyone else having trouble opening the devlog google doc? The first page loads a preview but nothing else appears. Says "couldn't preview file - there was a problem loading more pages."

Jip

Same issue - @maudlin27 maybe the file is too big?

maudlin27

@sioloc I've split it out into several documents to reduce the size slightly, let me know if you still have issues accessing.

SaintSaturday

Thank you so much for your work. I'm one of those players who really loves playing against AIs, but I hate AI that is too easy or cheats. It seems to me like you've made the best vanilla (well, vanilla-ish since it's on FaF) AI. It's currently kicking my ass. I'd really love it if you would continue working on it to make it even tougher, and also resistant to all sorts of cheesy tactics used by humans to beat it quickly. I also really like how it's not specialized for a single type of terrain and it can play navy as well. Anyway, just wanted to voice my appreciation.

v_k

Just came here to say thanks @maudlin27, this is really appreciated. Uveso was kinda challenging when using x1.5 multipliers, M27 is even better without even any multiplier. Can't wait for M28.