Tactical AI improvements

[yufra]

I have been experimenting with some changes to the tactical AI to improve how attackarea and eventually beam talents are used. What I am toying with right now is to have talents expose their main targeting definition so the tactical AI code (and maybe even the right-click menu) can grab it and figure out how many allies and foes a talent will hit. To explain the current state I set up this scenario: I spawned a modified Hydra (with the tactical AI and updated Breath and the Ritch bolt) on the opposite side of a mold. Why the bolt? Well it offers an alternative to the AoE breath attacks.

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H
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So the tactical AI goes through the talents and notices that the breath attacks will hit both an ally and a foe. I set a "ally_compassion" variable in the Hydra's ai_state which lets it know to heavily penalize against hitting allies, which is why they have such a small individual weight. I also changed the want.attackarea to use the ally/foe count from the highest weighted ATTACKAREA talent.

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============================== TACTICAL AI	3-headed hydra
3-headed hydra	1796	tactical ai talents can use	Flamespit	T_RITCH_FLAMESPITTER_BOLT	attack	weight	3.2100473305314
[DEBUG] hit an ally!
[DEBUG] hit a foe!
3-headed hydra	1796	tactical ai talents can use	Lightning Breath	T_LIGHTNING_BREATH_HYDRA	attackarea	weight	0.72013894538279
[DEBUG] hit an ally!
[DEBUG] hit a foe!
3-headed hydra	1796	tactical ai talents can use	Poison Breath	T_POISON_BREATH	attackarea	weight	0.18487997710712
[DEBUG] hit an ally!
[DEBUG] hit a foe!
3-headed hydra	1796	tactical ai talents can use	Acid Breath	T_ACID_BREATH	attackarea	weight	0.17515352346404
Tactical ai report for	3-headed hydra
 * attackarea	0.21553645107043
 * attack	4.79288167818
Tactical choice:	attack	T_RITCH_FLAMESPITTER_BOLT

The result? The ATTACK bolt is selected over the ATTACKAREA breaths. This is still really early, but I think it is the start for more accurate handling of AoE talents. Here is hoping!

EDIT: Oh, and I need to figure out how/if the GO_MELEE option is being used. Doesn't appear to be used right now...

EDIT2: Actually, I just realized that a negative want means the tactical category will be ignored. I changed that and now the bolt alternative isn't even necessary as seen in this quote...

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============================== TACTICAL AI	3-headed hydra
[DEBUG] hit an ally!
[DEBUG] hit a foe!
3-headed hydra	1796	tactical ai talents can use	Lightning Breath	T_LIGHTNING_BREATH_HYDRA	attackarea	weight	0.43717408436517
[DEBUG] hit an ally!
[DEBUG] hit a foe!
3-headed hydra	1796	tactical ai talents can use	Poison Breath	T_POISON_BREATH	attackarea	weight	0.079304709091517
[DEBUG] hit an ally!
[DEBUG] hit a foe!
3-headed hydra	1796	tactical ai talents can use	Acid Breath	T_ACID_BREATH	attackarea	weight	0.032451238890851
Tactical ai report for	3-headed hydra
[ATTACK] attacking with innate combat

[Marcotte]

That would indeed be a good improvement for ToME, especially it often happens that the player is fighting along creatures with AOE effects (summoners or alchemists being the main cases).

I'm planning on implementing something similar for intelligent casters in BOB (you can check that the targeting information for abilities is already accessible), but I haven't done it so far (I don't even let the AI check if there is anyone in the way of a bolt ability, but that's somewhat on purpose).

By the way, implementing something like using dummy projection also have the extra benefit of teaching the AI to cast ball spells when the target is just out of range, as long as the ball spread will reach them. And it will allow them to benefit from the off-by-one distance bug too (that one could lead to funny result with range-1 spells).

[yufra]

That would indeed be a good improvement for ToME, especially it often happens that the player is fighting along creatures with AOE effects (summoners or alchemists being the main cases).

Yup, that is one of the main hopes I have for this project.

By the way, implementing something like using dummy projection also have the extra benefit of teaching the AI to cast ball spells when the target is just out of range, as long as the ball spread will reach them. And it will allow them to benefit from the off-by-one distance bug too (that one could lead to funny result with range-1 spells).

It is true, I have already increased the "range" of spells by the sum of both range and radius in for the purposes of deciding if the tactical AI should attempt the dummy projection. After that the dummy projection collects the number of foes and allies hit, does some math and weights the talent with the result. I think I have all of the talents/code in place, but due to the scale of the change testing this is going to be tricky.

[yufra]

Alright, a bit on the technical side. I have changed the current behavior of "friendlyfire" to "selffire" and added a "friendlyfire" option. This allows you to differentiate talents between hitting the source of the talent (now selffire) and all allies (now friendlyfire). There are also two variables that can be set in the ai_state table of NPCs, "self_compassion" and "ally_compassion." These default to 5 and 1, respectively, and are weights that bias against ATTACKAREA if it would hit you or an ally, respecively. These can be set to range from "servile behavior" (low self_compassion, high ally_compassion) to "me first" (high self_compassion, 0 ally_compassion), to "psychopath" (0 self_compassion and ally_compassion).

Enough of technical talk, here is an example that will intrigue most players: the alchemist and his golem. I started Testme the Alchemist and immediately switched control to the golem to test how the new AI works. At first there was nothing in sight:

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============================== TACTICAL AI	Testme
Testme	142	tactical ai talents can use	Infusion: Regeneration	T_INFUSION:_REGENERATION_2	heal	weight	2.4343428021592
Testme	142	tactical ai talents can use	Rune: Manasurge	T_RUNE:_MANASURGE_1	mana	weight	1.9145789156229
Testme	142	tactical ai talents can use	Infusion: Wild	T_INFUSION:_WILD_3	defend	weight	36.681561663639
Testme	142	tactical ai talents can use	Gift of the Pureborn	T_HIGHER_HEAL	heal	weight	24.821997264353
Tactical ai report for	Testme
[PARTY AI] following master	Testme

But then a grey rat sneaks up on Testme and:

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[LOG]	Giant grey rat crawls poison onto Testme.

Now I haven't played with the DEFEND AI at all, but it does the right thing:

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============================== TACTICAL AI	Testme
Testme	142	tactical ai talents can use	Infusion: Regeneration	T_INFUSION:_REGENERATION_2	heal	weight	3.2991020740246
[DEBUG] hit an ally!
[DEBUG] hit a foe!
[DEBUG] hit self!
Testme	142	tactical ai talents can use	Throw Bomb	T_THROW_BOMB	attackarea	weight	0.75636969218239
Testme	142	tactical ai talents can use	Rune: Manasurge	T_RUNE:_MANASURGE_1	mana	weight	1.833423985742
Testme	142	tactical ai talents can use	Channel Staff	T_CHANNEL_STAFF	attack	weight	1.5122363507949
Testme	142	tactical ai talents can use	Infusion: Wild	T_INFUSION:_WILD_3	defend	weight	36.733531647309
Testme	142	tactical ai talents can use	Gift of the Pureborn	T_HIGHER_HEAL	heal	weight	24.269180612905
Tactical ai report for	Testme
 * defend	3.0117904259987
 * attack	2.6219430768068
Tactical choice:	defend	T_INFUSION:_WILD_3

And once he is defended, Testme sets about to do some damage. Note that while deciding the tactical weight for T_THROW_BOMB (0.42) there is a dummy projection that shows he would hit an ally (the player controlled golem) as well as a foe, resulting in a low weight and a negative want (not shown) so ATTACKAREA is discarded as an option (not shown in the Tactical ai report segment).

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============================== TACTICAL AI	Testme
Testme	142	tactical ai talents can use	Infusion: Regeneration	T_INFUSION:_REGENERATION_2	heal	weight	3.2852049698747
[DEBUG] hit an ally!
[DEBUG] hit a foe!
Testme	142	tactical ai talents can use	Throw Bomb	T_THROW_BOMB	attackarea	weight	0.42556243010719
Testme	142	tactical ai talents can use	Rune: Manasurge	T_RUNE:_MANASURGE_1	mana	weight	1.2698157574577
Testme	142	tactical ai talents can use	Channel Staff	T_CHANNEL_STAFF	attack	weight	2.0026311470617
Testme	142	tactical ai talents can use	Gift of the Pureborn	T_HIGHER_HEAL	heal	weight	24.515816430242
Tactical ai report for	Testme
 * attack	2.5209391415002
Tactical choice:	attack	T_CHANNEL_STAFF

So far so good. What if I move the golem out of the way?

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============================== TACTICAL AI	Testme
Testme	142	tactical ai talents can use	Infusion: Regeneration	T_INFUSION:_REGENERATION_2	heal	weight	2.4064778485031
[DEBUG] hit a foe!
Testme	142	tactical ai talents can use	Throw Bomb	T_THROW_BOMB	attackarea	weight	2.9873212289445
Testme	142	tactical ai talents can use	Channel Staff	T_CHANNEL_STAFF	attack	weight	1.2158420071735
Testme	142	tactical ai talents can use	Gift of the Pureborn	T_HIGHER_HEAL	heal	weight	24.550599283563
Tactical ai report for	Testme
 * attackarea	2.3617680636236
 * attack	2.0506774491828
Tactical choice:	attackarea	T_THROW_BOMB

Success! The tactical AI respects allies and hitting itself (not shown) with AoE. Note that the AI will not shift the targeting off of the target to optimize the number of foes versus number of enemies, so for example if you are facing a radius 1, selffire AoE enemy and always stay adjacent to it the AI will never shift the target off to the side to hit you and not it. The easier solution to that one is to give some escape talents, though.

[Grey]

This highlights something we need in the game - psychopath alchemist enemies!

More seriously though, cool work, with a lot of good potential for improving the current AI.

[edge2054]

Great work yufra, I look forward to testing it with a Paradox Clone

[yufra]

Alright, it is time for extensive testing. Edge got an earlier version of this patch and between the two of us we found and squashed some bugs, but in order to test it all I need more bodies on the problem. Definitely report any Lua errors you see in this thread, but also report more subtle things. For example, wyrms were not breathing over their progeny because I had forgotten to remove their "ally_compassion" setting. Thanks!

[yufra]

Here is an updated patch.

[yufra]

Alright, the changes are in SVN now... let me know how it goes!

[tiger_eye]

Just wondering, does "friendlyfire" account for resistances of allies? I don't think a fire drake would have any problem breathing a cone of fire onto their brethren...

[yufra]

Just wondering, does "friendlyfire" account for resistances of allies? I don't think a fire drake would have any problem breathing a cone of fire onto their brethren...

Currently friendlyfire does not account for resistance since the tactical AI has no concept of resistances or damage types. I am not sure if we will add this feature since it is an obvious one to add, but we must be wary of having tactical AI do too much and risk slowing things down. Currently drakes simply ignore allies and breath willy-nilly.

[Marcotte]

Currently friendlyfire does not account for resistance since the tactical AI has no concept of resistances or damage types. I am not sure if we will add this feature since it is an obvious one to add, but we must be wary of having tactical AI do too much and risk slowing things down. Currently drakes simply ignore allies and breath willy-nilly.

I don't think this feature will have much impact, CPU-wise. It pretty much changing the way hits are counted from:

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nb_foes_hit = nb_foes_hit + 1

to

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nb_foes_hit = nb_foes_hit + math.max(0, 100 - act.resists[damage_type])

, so the overhead should be minimal. The only issue is that you add yet another field to talents to tell the AI what damage_type it is using, which can get complicated for some talents (like alchemist bombs).

[yufra]

The only issue is that you add yet another field to talents to tell the AI what damage_type it is using, which can get complicated for some talents (like alchemist bombs).

Yes, that is the issue... but I already updated most talents to have targets so why not damage types? I am not terribly concerned about alchemist bombs, that can be handled by having damage_type be a function just like target/range/radius can be now. The side effect would be that the tactical AI would also take into account the player's resistances... which is a good thing as well. So... when I am feeling up to it.

[marvalis]

Summoner ai problems: in b21, with the new ai, there are a few problems:
* Flamespitter seems to run away at all times, usually it is inappropriate.
* Turtle does not seem to use taunt as often as before.
* Turtle tries to escape

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============================== TACTICAL AI	turtle
turtle	22449	tactical ai talents testing	Shell Shield	T_SHELL_SHIELD
turtle	22449	tactical ai talents testing	Taunt	T_TAUNT
turtle	22449	tactical ai talents can use	Taunt	T_TAUNT	protect	weight	20.59069955933
turtle	22449	tactical ai talents testing	Attack	T_ATTACK
Tactical ai report for	turtle
 * escape	4.5681988651445

He should be tanking not running :3

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============================== TACTICAL AI	ritch flamespitter
ritch flamespitter	22720	tactical ai talents testing	Flamespit	T_RITCH_FLAMESPITTER_BOLT
[DEBUG] hit a foe!
ritch flamespitter	22720	tactical ai talents can use	Flamespit	T_RITCH_FLAMESPITTER_BOLT	attack	weight	600.30854163899
ritch flamespitter	22720	tactical ai talents testing	Equilibrium Pool	T_EQUILIBRIUM_POOL
ritch flamespitter	22720	tactical ai talents testing	Attack	T_ATTACK
[DEBUG] hit a foe!
ritch flamespitter	22720	tactical ai talents can use	Attack	T_ATTACK	attack	weight	120.67806006543
Tactical ai report for	ritch flamespitter
 * escape	12.678125669323
 * attack	2.0078181265197

No matter how high attack and flamespit are, the AI still prefers to run for it.

[yufra]

Great report marvalis, thanks. I will be looking at the tactical AI this weekend, and hopefully have those things hammered out soon.