I’ve spent some more time looking at the AI for Doomdark’s Revenge, trying to work out why it doesn’t quite appear to be playing like the original. One thing I noticed is that I have completely misunderstood the recruiting logic when it comes to Loyalty and Treachery. I made changes in the last version, but I am going to need to revert them.

The approach algorithm

• compare the the attributes of the lords and looking for matches gain +1 for each match.
• If the character being approached is not loyal then +1
• If the character being approached is treacherous then * 2
• if the recruiting character is the liege of the character being approached then +3
• If the recruiting character carries a crown of persuasion then +2
• If the score is greater than 3 then the approach will succeed.

The basic concept that I have misunderstood is: Loyal characters are less likely to be recruited away form their current liege and un-loyal characters are more likely, therefore the algorithm gets a +1 for none loyal characters. And that treacherous characters are more likely to leave and thus the *2

The next thing I have missed is the lords following the objectives of their lieges.

It works like this.

If the lord has a liege and that liege is following their liege or their foe, then we must follow our liege. Otherwise pick a new objective.

There is a 32% chance that we will pick a new objective. Although that should be 25% because we could pick the objective we already have. That leaves a 68%/75% chance that we continue doing what they were already doing.

The problem for me is the first check. If we use Shareth as an example. She has a 12.5% chance that she will choose to follow either her foe or leader. As she has no leader she reverts to Luxor, which is her foe. So she has a 12.5% chance that she will follow Luxor. All the lords that follow her now have a 100% chance of following Shareth, and this ripples all the way down the stack of lords. Which at the start of the game means that 47 Icelords will disregard what they are doing and follow her.

The mistake I had made is that I had made the following lords take the objectives of their liege when their liege was following their liege or foe. What this means is that when the liege is following their foe the lord follows their own foe. So using Shareth again as the example, when she is following her liege ( Luxor by default ) then all her minions will head to her location, but when she is following her foe ( Luxor ), then all her minions are heading to their foe and not to her location. So as an example, Imgaril the Icelord would be heading to Imgorthand the Fey, who, is likely the the other direction of Shareth.

Hopefully this fix should make the game more like the original, but it bothers me that it is a flawed AI. I ran the game for the first ten days, up until the first battle took place, I ran it on the emulator too to compare notes. Here is what Shareth did over those days.

1. Head Home
2. Head Home
3. Head Home
4. Follow Luxor
5. Head Home
6. Follow Luxor
7. Follow Luxor
8. Follow Luxor
9. Search for object
10. Head home

Now Talormane does this

1. Head Home
2. Head Home
3. Search for object
4. Search for object
5. Follow Lorelorn
6. Follow Lorelorn
7. Follow Lorelorn
8. Follow Lorelorn
9. Follow Lorelorn
10. Follow Asorthane

The reason for the delayed follow on day 4 is because Talormane is following Lorelorn who is following Shareth, but Lorelorn is lower in the processing order than Talormane, and thus Talormane doesn’t know that Lorelorn is going to follow Shareth in that turn.

The final thing that I changed was that there is a 6.25% chance that the change of objective will be DO NOTHING. This is especially important for being in a battle with someone who is not the lords foe, because it means that without this the lord will always leave the battlefield. The mistake I had made was that I persisted the do nothing as an objective, i.e.. The lords objective becomes do nothing. But it shouldn’t, it should stay the same as the previous objective, and this turn that objective is ignored.

Going back to Shareth. If she chose to DO NOTHING then her objective would no longer be follow liege or foe, which means that her followers would be able to perform whichever objective they chose. However, if her previous objective had have been follow liege or foe, then her followers should still be heading towards her when she chooses to do nothing. This would have the affect of allowing them to catch up on her.