bugfix(ai): Prevent units from deploying when moving

[Caball009]

• Closes China Nuke Cannon can creep forward after firing #176

This PR prevents units from deploying when they're still moving. The issue is most notable with the Nuke Cannon, which deploys and fires just ahead reaching its goal position (see issue).

The pathfinding code uses Weapon::isGoalPosWithinAttackRange, while the deployment code uses isWithinAttackRange. The former uses a smaller range than strictly necessary, so that attacks don't fail all the time on moving targets. That's why units deploy just ahead of reaching their goal position.

#176 (comment)

Notes:

• This is probably a very minor nerf because the attack range has been reduced a tiny bit.
• This change assumes that unit movement and deployment are always mutually exclusive.

[Caball009]

I tried using isGoalPosWithinAttackRange for deployment as well, but that had mixed results because sometimes the Nuke Cannon wouldn't deploy at all.

Even if fixed, an isMoving check is still necessary because units might get a range bonus after receiving an attack order but before reaching their goal position; without it, units could still deploy too early.

[greptile-apps]

Greptile Summary

Prevents deploy-style Zero Hour units from deploying while their AI reports active movement.

• Preserves original behavior for retail-compatible CRC builds.
• Adds a movement check before range-triggered deployment in non-retail builds.

Confidence Score: 5/5

The PR appears safe to merge, with no concrete changed-code regression identified.

The new condition blocks range-triggered deployment while movement is active, while existing move handling still transitions deployed or deploying units toward undeployment.

Important Files Changed

Filename	Overview
GeneralsMD/Code/GameEngine/Source/GameLogic/Object/Update/AIUpdate/DeployStyleAIUpdate.cpp	Adds a non-retail movement guard to range-triggered deployment without changing guard-idle or retail-compatible behavior.

_{Reviews (1): Last reviewed commit: "bugfix(ai): Prevent units from deploying..." | Re-trigger Greptile}

[xezon]

Needs to be replicated to Generals?

[xezon]

I wonder if the isTryingToMove and ai->isMoving() should be consolidated. Do both of them try to conclude the same condition?

[Caball009]

Good point. I'll have a look.

[Caball009]

I think that works; changed.

[xezon]

I tested this branch and it does not fix the Nuke Cannon deployment bug. Tested on map https://github.com/TheSuperHackers/GeneralsGamePatch/tree/main/Maps/Any/!TestAllFactionsBuildingsUnitsPromo

[Stubbjax]

I tested this branch and it does not fix the Nuke Cannon deployment bug. Tested on map https://github.com/TheSuperHackers/GeneralsGamePatch/tree/main/Maps/Any/!TestAllFactionsBuildingsUnitsPromo

It does appear to fix TheSuperHackers/GeneralsGamePatch#269 though.

[xezon]

Accidental fix )

[Caball009]

I tested this branch and it does not fix the Nuke Cannon deployment bug. Tested on map https://github.com/TheSuperHackers/GeneralsGamePatch/tree/main/Maps/Any/!TestAllFactionsBuildingsUnitsPromo

Can you share a VS22 replay of this?

[xezon]

Repro: Put Guard Mode behind a blob of units on this test map.

[Caball009]

I suspect you're seeing other yet unfixed issues with the Nuke Cannon. With the fix in place, I cannot reproduce the issue shown in the video here #176 (comment). Would like to see a VS22 replay still.

[Stubbjax]

Repro: Put Guard Mode behind a blob of units on this test map.

Try attacking a target outside the Nuke Cannon's range and observe whether it creeps forward after deployment.

[Caball009]

Needs to be replicated to Generals?

I haven't verified this, but the posts in the issue suggest this is not an issue for Generals. Function DeployStyleAIUpdate::update is quite different there.

[xezon]

Here is replay with this branch in RTS_DEBUG vs22 build.

nuke_cannon_bug.zip

[Caball009]

The fix is non-retail. It seems like you're testing without removing the retail compatibility guard.

[xezon]

Ohhhhhhhhhhhhhhhhhhhh silly me......

time to go to sleep