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#1 2013-08-25 09:33:42

NPPAngband Maintainer
Registered: 2004-07-01
Posts: 1,647

Thoughts on monster AI

As I search for something to do in the game, the other thing I would want to give a major overhaul to is monster AI.  4gai was a major improvement, but a much more complicated version of earlier, where the mosnter chooses between   1) moving to the player (physical attack if next to the player, 2) moving away from the player 3) casting a spell.

I think it could be broken out a little further, and give the monster these choices:

1) move to the player
2) hide from the player
3) decide on a tactic (heal, run/teleport away, attack, move to a more advantagous position, summon monsters)
4) wait in an area for the player to approach/guard an area
5) for group monsters, make the decision as a group and move/attack as a squad.  I think I can even have them split into groups and attack the player from two sides if the pattern of the hallways/rooms permits it.

I think monster mana could be eliminated.  Instead give the monster a finite number of times to teleport the player away, or teleport to/from the player and other spells that would be completely unfair if given in unlimited number (the whole point of monster mana in the first place).

For group monsters, the main monster would hide from site while it's escorts all fight to the death.  So the player would have to fight through the escorts to get to the main unique.

My goal would be to have varying AIs for different monsters.  Dumb monsters just move unintelligently at the player. Average monsters would behave about like 4gai has them behavbe now. Smart monsters would be given a smart AI, and could only be killed through long, epic battles.  These smart/powerful monsters would have much better monster drops, and greatly reduce thier number.  This would hopefully reduce the "too much junk" problem, and the overall absurdity of the player fighting and killing 300 great wyrms on a level, receiving 3000 good/great object drops in the process.

Does anyone have any thoughts on the subject?  In general, I am searching for inspiration on what to do next.  I could also do a frog-knows module for NPP as well.


#2 2013-08-25 10:34:31

Registered: 2007-10-22
Posts: 104

Re: Thoughts on monster AI

I think it would be wonderful to see a few things improved.
Levels of intelligence in the mobs behavior would be nice. The Dumb, Average, Smart and maybe even Genius AI levels, while increasing the quality of drops commensurate with their increased threat sounds like a great idea.

As well...

-Intelligent attack selection.Take mobs like the Priest, if you are across a room from them the Orb of Draining hits you for a significant amount of damage. Yet if you get into melee range they switch primarily to a melee attack that barely does anything when compared to the OoD. So on mobs like that closing to melee range pretty much destroys their combat ability.

-Using actual tactics against players. Mobs that don't blindly charge when they are ranged based, but instead should attempt to stay at range until out of mana, and only then close. Mobs kiting players, and mobs Pillar Dancing players around, etc...


#3 2013-08-27 10:05:58

Diego Gonzalez
NPPAngband Source Contributor
Registered: 2004-10-09
Posts: 292

Re: Thoughts on monster AI

Hounds are very easy to kill in NPP. It would be great if they don't advance to the player sometimes to make the player vulnerable to multiple breath attacks, as in FAA.

IMHO, monsters of the same race shouldn't behave always in the same way. Sometimes a pack of hounds should be generated more aggresive and always move towards the player, other times they should stay in some location, perhaps protecting an excellent item, near native terrain (like having lairs), or just staying because. The same goes for lonely monsters. It will be funny to see Shelob protecting the Phial...

In other words, what I imagine is monsters having a set of flags set from the edit files and another set randomly assigned, like the impulse to advance to the player.

Of course, there are things that are hard to balance, like a spellcaster that is never adjacent to the player, like archers in Sil. The problem with this is that you need to have a decent archery skill or access to ranged spells. Perhaps they can be trapped against a corner of the room by "only melee" characters, again, as in Sil.

It will be interesting to have monsters most of the time hidden in native terrain or outside of los, but in line of fire, like behind some tree branches. Of course, monsters should know that the player doesn't have telepathy and take advantage of ranged attacks.

Monsters should also exploit terrain some more. By example, a multi-hued dragon should be more biased to breathe frost if the player is standing over ice or water, or breathe fire if the player is standing over something that transforms into some kind of fiery feature, or if the player is using melee the monster should stay over native terrain to get some extra protection, and things like that.



#4 2013-08-27 23:49:57

Registered: 2012-02-27
Posts: 246

Re: Thoughts on monster AI

One thing that has bugged me is that creatures don't interact with terrain much.  Like cold monsters should really want to avoid a room full of fire.  And, they should want to move through cold terrain even if there is a more direct path.

Themed levels should also be affect the types of monsters on it.  If a level has lots of cold terrain, then it should bias towards cold monsters and away from fire monsters.  Especially when generating monsters on a grid, it should read the terrain there and prefer monsters native to that terrain.


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