Make AI use the signaling agent and add more conditions for responding to commands by IdfbAn · Pull Request #6736 · Revolutionary-Games/Thrive

IdfbAn · 2026-02-15T12:20:48Z

Brief Description of What This PR Does

This PR makes the microbe AI use the signaling agent and adds more conditions for responding to commands.

Related Issues

Closes #5118
Discussion: https://forum.revolutionarygamesstudio.com/t/how-should-ai-use-the-signaling-agent/1233

Progress Checklist

Note: before starting this checklist the PR should be marked as non-draft.

PR author has checked that this PR works as intended and doesn't
break existing features:
https://wiki.revolutionarygamesstudio.com/wiki/Testing_Checklist
(this is important as to not waste the time of Thrive team
members reviewing this PR)
Initial code review passed (this and further items should not be checked by the PR author)
Functionality is confirmed working by another person (see above checklist link)
Final code review is passed and code conforms to the
styleguide.

Before merging all CI jobs should finish on this PR without errors, if
there are automatically detected style issues they should be fixed by
the PR author. Merging must follow our
styleguide.

AI_SIGNALING_CHANCE is so that it's not used a billion times per second (Thanks to Patryk26g for suggesting to use NextSingle instead of Next) This is only the very beginning of this.

src/microbe_stage/systems/MicrobeAISystem.cs

src/microbe_stage/components/MicrobeControl.cs

src/microbe_stage/systems/MicrobeAISystem.cs

hhyyrylainen · 2026-02-16T09:10:10Z

src/microbe_stage/systems/MicrobeAISystem.cs

+        // Use signaling agent if I have any with a chance of 5% per think
+        if (organelles.HasSignalingAgent && random.NextSingle() < Constants.AI_SIGNALING_CHANCE)
+        {
+            UseSignalingAgent(ref organelles, speciesAggression, ref signaling, ref control, random);


It seems like there's only one case where the signalling command is set to None. That means that cells do not stop signalling! That's a very, very major bug in my opinion because eventually I think most cells will just be signalling all the time.

Also I think another key part still missing is that cells should decide to ignore an incoming signalling command in certain situations (like if become aggressive signal is too far away, or a move signal is far away and the cell is not that full on resources).

Without those two things I think the signals will quite effectively destroy any useful AI behaviours as they'll get permanently locked into following the signal of the first species member of them that triggered it.

Do you have suggestions for when it should be set to no command?

I'd say whenever the original condition to set a signal is gone, or like after 15-30 seconds of the cell not feeling like it should send the same signal again. Something like that, but I'm sure someone else more familiar with the AI could come up with a more advanced codnitions.

src/microbe_stage/systems/MicrobeAISystem.cs

Patryk26g · 2026-02-24T19:28:30Z

src/microbe_stage/systems/MicrobeAISystem.cs

+        else
+        {
+            signalExists = false;
+        }


is this "else" needed? can do without it, just make "bool signalExists = signaling.ReceivedCommand != MicrobeSignalCommand.None && entity.IsAliveAndHas()". Btw what is " entity.IsAliveAndHas()" used for? Shouldn't it be "signaling.ReceivedCommandFromEntity.IsAliveAndHas()"?

Btw what is " entity.IsAliveAndHas()" used for?

It's so that the game doesn't crash when there isn't a signal.

This else still should be removed... it literally if signal == false then signal = false

src/microbe_stage/systems/MicrobeAISystem.cs

Patryk26g · 2026-02-24T19:33:42Z

src/microbe_stage/systems/MicrobeAISystem.cs

+    private void UseSignalingAgent(ref OrganelleContainer organelles, float speciesAggression,
+        ref CommandSignaler signaling, Random random)
+    {
+        var willBeAggressiveThisTime = RollCheck(speciesAggression, Constants.MAX_SPECIES_AGGRESSION, random);


willBeAggressiveThisTime -> shouldBecomeAggresive

Personally, I think that's an inaccurate name considering what the variable is being used for.

As I said in other comment, future tense variables should be omitted.

Patryk26g · 2026-02-24T19:34:46Z

src/microbe_stage/systems/MicrobeAISystem.cs

+                signaling.QueuedSignalingCommand = MicrobeSignalCommand.None;
+            }
+        }
+        else


this else is unnecesary

I guess it is right now, but since I want to add more sub-conditions I'll keep it.

Are you going to do this in this PR? If not, then you should remove it. YAGNI

Yes, I'm gonna do it in this PR.

So there was unimplemented stuff? Good thing that I didn't spend any more review energy yet...

src/microbe_stage/systems/MicrobeAISystem.cs

Patryk26g · 2026-02-24T21:50:59Z

src/microbe_stage/systems/MicrobeAISystem.cs

+
        // Adjusted behaviour values (calculated here as these are needed by various methods)
        var speciesBehaviour = ourSpecies.Species.Behaviour;
+        var willAdjustBehaviourValues = signaling.ReceivedCommand == MicrobeSignalCommand.BecomeAggressive &&


I think we should omit future tense in variables... adjustBehaviourValues is fine. or event better "shouldBeAggresive"

You know, I never thought about it, but you are right that future tense is not used in variable names customarily. So yeah, this sounds like a good naming change, and I would definitely have named this variable something along the lines of needsToAdjustBehaviour.

Patryk26g · 2026-02-24T21:52:18Z

src/microbe_stage/systems/MicrobeAISystem.cs

+        bool signalExists = signaling.ReceivedCommand != MicrobeSignalCommand.None &&
+            entity.IsAliveAndHas<WorldPosition>();
+        Vector3 signalerPosition = default;
+        float squaredDistanceToSignaler = default;


squaredDistanceToSignaler -> signalerDistanceSquared

Accidental-Explorer · 2026-02-26T11:19:42Z

src/microbe_stage/systems/MicrobeAISystem.cs

            ai.ATPThreshold = 0.0f;
        }

+        // Use signaling agent if I have any with a small chance per think


Is this supposed to be "per tick"?

I hope not because we do not have "ticks" in the game (the closest concept we have is a game simulation update)...

I do mean "think", as in each time AIThink() is called. I guess it should say "per update", then?

I think "per think" is perfectly understandable, and I have a feeling that there are existing comments that are of similar format. But for clarity it could be written as "per think method call".

Accidental-Explorer · 2026-02-26T11:37:20Z

src/microbe_stage/systems/MicrobeAISystem.cs

+    private void UseSignalingAgent(ref OrganelleContainer organelles, float speciesAggression,
+        ref CommandSignaler signaling, Random random)
+    {
+        var shouldBeAggressive = RollCheck(speciesAggression, Constants.MAX_SPECIES_AGGRESSION, random);


So this, combined with the section below is just deciding whether they should be trying to travel in a group? (Because this is outside specific responses, just passive, right?)

I think this would make sense not just for aggressive predators, but also for some Brave prey.

This comment looks like it was not marked as solved?

Patryk26g told me to not resolve (his) comments as solved myself.

You should ask for a review again / comment again mentioning their name to ask for further feedback if a reviewer is not responding in a reasonable amount of time to your further changes (I do know from personal experience that it is easy to miss new changes that were related to a review comment I left).

The actual defense part should be covered by the shouldBeAggressive condition in UseSignalingAgent()

hhyyrylainen · 2026-04-07T14:11:26Z

src/microbe_stage/systems/MicrobeAISystem.cs

        var compounds = compoundStorage.Compounds;

+        bool signalExists = signaling.ReceivedCommand != MicrobeSignalCommand.None &&
+            entity.IsAliveAndHas<WorldPosition>();


Isn't entity wrong here? The system should not even run if the entity is dead, so shouldn't this code be checking if ReceivedCommandFromEntity is the one that is alive?

hhyyrylainen · 2026-04-07T14:12:30Z

src/microbe_stage/systems/MicrobeAISystem.cs

+        var adjustBehaviourValues = signaling.ReceivedCommand == MicrobeSignalCommand.BecomeAggressive &&
+            signalerDistanceSquared < Constants.AI_BECOME_AGGRESSIVE_DISTANCE_SQUARED;


I think this needs to check the signalExists safety flag as well because theoretically the received command might be left to aggressive command but then there signaller doesn't exist.

hhyyrylainen · 2026-04-07T14:13:44Z

src/microbe_stage/systems/MicrobeAISystem.cs

                    {
-                        ai.MoveToLocation(signaling.ReceivedCommandFromEntity.Get<WorldPosition>().Position,
-                            ref control, entity);
+                        if (signalerDistanceSquared < Constants.AI_MOVE_DISTANCE_SQUARED)


How small is this distance? The signal is literally meant to bump into other members to make using the binding agent easy for the player, so I don't really agree with this change...

hhyyrylainen · 2026-04-07T14:16:27Z

src/microbe_stage/systems/MicrobeAISystem.cs

+
+        if (organelles.HasBindingAgent)
+        {
+            signaling.QueuedSignalingCommand = MicrobeSignalCommand.MoveToMe;


This line seems useless so should be deleted (there's no early exit so we always execute the line signaling.QueuedSignalingCommand = MicrobeSignalCommand.None; after this).

Or alternatively it could be use some logic to detect when cells would be good to group together and would then set this but only if already in binding mode / going into binding mode, as otherwise it is useless to trigger this signal.

Doesn't it make more sense to remove the signaling.QueuedSignalingCommand = MicrobeSignalCommand.None; right at the end of the function?

Well there has to be a some quite common condition to reset the signal as I don't want the AI to be entirely made so that it is assumed that there's almost always a signal. It is better for signals to only be sent occasionally so that the AI just doesn't become a total mess where it is always just forced to respond to other signals.

Also for safety I think most "non-urgent" signals should not be activated if the current cell is receiving another signal as that just adds to the signal noise.

hhyyrylainen · 2026-04-07T14:18:00Z

src/microbe_stage/systems/MicrobeAISystem.cs

+                if (organelle.Definition.HasPilusComponent || organelles.AgentVacuoleCount > 0)
+                {
+                    var membersNearEnough = 0;
+                    var enoughMembers = (int)speciesAggression / 100;
+
+                    foreach (var member in speciesMembers!)
+                    {
+                        if (position.Position.DistanceSquaredTo(member.Position)
+                            < Constants.AI_BECOME_AGGRESSIVE_DISTANCE_SQUARED)
+                        {
+                            ++membersNearEnough;
+                        }
+                    }
+
+                    if (membersNearEnough >= enoughMembers)
+                    {
+                        signaling.QueuedSignalingCommand = MicrobeSignalCommand.BecomeAggressive;
+                        break;
+                    }
+
+                    signaling.QueuedSignalingCommand = MicrobeSignalCommand.FollowMe;
+                    break;
+                }
+
+                signaling.QueuedSignalingCommand = MicrobeSignalCommand.None;


This loop looks very suspicious to me. I think instead what you actually want to do is first setup variables for pilus count, and then do a count of pili, and only then would you do the membersNearEnough calculation as that's an expensive calculation to do each loop iteration so I'm quite sure you didn't meant to put that logic inside this loop.

IdfbAn added 12 commits February 11, 2026 21:48

AI: Use move to me command if entity has binding agent

224cb54

AI_SIGNALING_CHANCE is so that it's not used a billion times per second (Thanks to Patryk26g for suggesting to use NextSingle instead of Next) This is only the very beginning of this.

AI Signaling Agent: Add else condition for no command

51c70e1

MicrobeAISystem.UseSignalingAgent()

8d88abe

Make UseSignalingAgent() return the command

d5ed2a0

Make returning no command outside of conditions

e491f3d

Start adding conditions for predation

2d9a1c6

Comply with JetBrains check

a45ef6b

Make UseSignalingAgent() set commands directly again

144a74b

Add "or has toxins" to pili condition

4d8bc43

MicrobeControl.Fleeing

e9f1932

Set control.Fleeing in ChooseActions()

8195e59

Use flee from me command if fleeing

ecca883

github-project-automation bot added this to Thrive Planning Feb 15, 2026

github-project-automation bot moved this to In progress in Thrive Planning Feb 15, 2026

$xfractalino$

xfractalino reviewed Feb 15, 2026

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$xfractalino$

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Remove control.Fleeing = false line

36de1a4

hhyyrylainen reviewed Feb 16, 2026

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IdfbAn added 8 commits February 16, 2026 14:24

Remove exact chance from comment

f5fc4c8

Move Fleeing to MicrobeAI and increment SERIALIZATION_VERSION

07f62e2

Handle reading Fleeing for SERIALIZATION_VERSION == 1

08cbe44

Correct control.Fleeing to ai.Fleeing

c758755

Add else conditions that set command to none

0920682

Add and use AI_MOVE_DISTANCE_SQUARED

74ac805

Add and use AI_BECOME_AGGRESSIVE_DISTANCE_SQUARED

4c1708e

Fix indentation

d471a74

IdfbAn marked this pull request as ready for review February 23, 2026 15:46

IdfbAn requested review from a team February 24, 2026 10:03

Patryk26g reviewed Feb 24, 2026

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Patryk26g reviewed Feb 24, 2026

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Use signalExists in signalerPosition condition

3426b61

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Fulfill (some of) Patryk26g's requests

01abd06

Patryk26g reviewed Feb 24, 2026

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Resolve JetBrains check fail and fulfill new Patryk26g requests

0301823

IdfbAn marked this pull request as draft February 25, 2026 07:53

Accidental-Explorer reviewed Feb 26, 2026

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IdfbAn added 3 commits February 26, 2026 17:48

Change comment as suggested by hhyyrylainen

e1d3cc1

Add condition for sending become aggressive command

9179fa4

Send follow me command if prey is confident enough

8d134db

The actual defense part should be covered by the shouldBeAggressive condition in UseSignalingAgent()

IdfbAn marked this pull request as ready for review March 31, 2026 16:25

IdfbAn requested review from Patryk26g and hhyyrylainen April 2, 2026 11:12

Merge branch 'master' into 5118_ai_signaling_agent

9d5b1f8

hhyyrylainen reviewed Apr 7, 2026

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		var adjustBehaviourValues = signaling.ReceivedCommand == MicrobeSignalCommand.BecomeAggressive &&
		signalerDistanceSquared < Constants.AI_BECOME_AGGRESSIVE_DISTANCE_SQUARED;

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IdfbAn commented Feb 15, 2026 •

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