Exercising The AI

The following files are potentially inconsistent between different end-of-turns, when no alien sights an X-COM unit or vice versa:

• SMOKREF.DAT (when there is smoke)
• ROUTES.DAT
• UNITPOS.DAT (cf. comments below)
• UNITREF.DAT (both XCOM and alien units)

LOC.DAT and IGLOB.DAT may be unstable at the start of a series of load-end turn-save tests, but this does not last.

Points of further investigation for patrol mode AI:

• Bit 4 at offset 19 in the ROUTES.DAT records: this influences the AI. In my current test suite, both "different nodes" from my reference save were to nodes that had their offset 19 bit 4 set during the AI turn. The reference save had offset 19 bit 4 set for the default node, but its being reset during the AI turn did not itself cause the AI to go to a different node.
• For each alien, the starting move at the start of the alien turn appears fully deterministic. Perhaps...UNITREF.DAT byte 70 indexes the immediate destination node? (Note: bytes 69 and 70 may be used differently in different AI modes.)

It will take a while to induct the transition probabilities for bit 4, offset 19 in the ROUTES.DAT records for nodes sourced from UFO reference data. Several are already clearly not 50% individually.

Also, is there a quick way to diagnose what AI mode is applicable (both locally and globally)?

-- Zaimoni, 16:58 CST Nov. 18 2006

It's unclear whether attack-mode AI state is fully saved or not. I had some severe non-reproducibility issues in recent testing.

-- Zaimoni, 14:532 CST June 24 2010

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I'm not sure whether this is specific to XCOMUTIL or not. Floaters have problems with stairs. I haven't gotten around to testing this with Ethereals.

Floaters can go up stairs fine (verified in a recent game), but I'm having problems catching them in the act of going down stairs. They are often found at the RMP node at the top of the stairs, facing due West (internal facing 6). From TU usage I think they do spin around, but the facing west and position are a steady state.

-- Zaimoni, 15:25 CDT Apr. 2 2008

What, more trouble than X-Com troops do? :) My troops are always going down stairs when they shouldn't, or not going down stairs when they should. Spike 11:49, 4 April 2008 (PDT)

I micromanage the waypoints as part of visibility control anyway, so I haven't really noticed the XCOM issues. It does make floaters very easy prey for commandos. Non-flying aliens are unimpaired, of course. -- Zaimoni, 13:32 CDT Apr. 6 2008

Floaters have problems with stairs under Seb76's loader as well. Furthermore, in the debugging modes, it is not possible to start going down stairs the way a flying-suit X-COM unit does (select the stair rather than the square in empty space)

-- Zaimoni, 14:28 CDT June 24 2010

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Pedantry: X-COM CE with XComUtil 9.6, used an Interceptor with 6 crew. The power plant explosion killed all but 2 floaters.

The general procedure (in Battlescape):

• Save the game at the end of turn.
• End Turn.
• Save game at the beginning of turn.
• copy *.dat *.bak

Then:

• Reload end-of-turn game.
• End Turn.
• Save game at the beginning of turn...in the same slot.
• fc /B *.dat *.bak > diff1.txt
• repeat, until "enough difference files have been constructed".

-- Zaimoni, 11:20 AM CST Nov. 18 2006