-= Gametoast.com =-

Posted: **Wed Apr 14, 2021 1:44 pm**

As the title says I am trying to create a remote droid that detonates upon impact with an enemy AI. Unfortunately ExplosionImpact doesn't work on Droid classes and I couldn't figure out any other way, so I tried to achieve it with Lua scripting. That's the code I created:

Code: Select all

nikitaUnit = nil
print("nikitaUnit:", nikitaUnit)

CreateTimer("NikitaPosUpdate")
SetTimerValue("NikitaPosUpdate", 1)

OnCharacterDispenseControllable(
	function(player, controllable)
		if GetEntityClass(controllable) == FindEntityClass("rep_weap_inf_remotedroid_ord") then
			nikitaUnit = controllable
			print("nikitaUnit:", nikitaUnit)
			
			StartTimer("NikitaPosUpdate")
		end
	end
)

OnTimerElapse(
	function(timer)
		if nikitaUnit then
			print("nikitaUnit:", nikitaUnit)
		
			nikitaX,nikitaY,nikitaZ = GetWorldPosition(nikitaUnit)
			print("Nikita X: ", nikitaX)
			print("Nikita Y: ", nikitaY)
			print("Nikita Z: ", nikitaZ)
			
			local teamSize = GetTeamSize(2)
			
			for i = 0, teamSize - 1 do
				enemyIndex = GetTeamMember(2,i)
				print("Getting Position of Enemy ", enemyIndex)
				enemyX,enemyY,enemyZ = GetWorldPosition(GetCharacterUnit(enemyIndex))
				print("Enemy X: ", enemyX)
				print("Enemy Y: ", enemyY)
				print("Enemy Z: ", enemyZ)
				
				if (math.abs(enemyX - nikitaX) <= 32) and (math.abs(enemyY - nikitaZ) <= 32) then
					print("Collide with Enemy ", enemyIndex)
					KillObject(nikitaUnit)
				end
			end
		end 
		
		SetTimerValue("NikitaPosUpdate", 1)
		StartTimer("NikitaPosUpdate")
	end,
	"NikitaPosUpdate"
)

Explanation
Once the player uses the remote droid, a timer is started. if the remote droid is alive, the function fetches its X,Y,Z coordinates and the X,Y,Z coordinates of every enemy AI. Then it checks for every enemy if the distance between the remote droid and that enemy is below a certain number. If this is true, the remote droid explodes. If this is false, the timer starts anew.

Problem
Everything works fine (as far as I can monitor it with the print commands) up until the point where the remote droid is near an enemy. The math statement is not being executed and I don't get a print entry in the BF2Log. And once the droid gets destroyed through time or an enemy shot, the game crashes.

Does somebody know how to prevent the CTD and make sure the math statement is being checked/executed correctly?

Posted: **Wed Apr 14, 2021 1:54 pm**

Is it a mistake that you're comparing enemyY with nikitaZ?

This is a really simple suggestion that probably won't be it, but I faintly remember having trouble with commands like if math.random(1, 6) == 1 then which I think I solved by doing the math.random outside of the if statement. It wasn't a crash though. What happens if you do the math.abs before you do the if?
eg.

Code: Select all

local xDifference = math.abs(enemyX - nikitaX)
local yDifference = math.abs(enemyY - nikitaY)
local zDifference = math.abs(enemyZ - nikitaZ)
if (xDifference <= 32) and (yDifference <= 32) and (zDifference <= 32) then
	print("Collide with Enemy ", enemyIndex)
	KillObject(nikitaUnit)
end

Posted: **Wed Apr 14, 2021 2:21 pm**

Awesome, that did the trick! Now the math statement gets executed and I get a response.

BF2Log.txt

Hidden/Spoiler:

nikitaUnit:    userdata: 07E37CC0

Nikita X:     -164.08102416992

Nikita Y:     1.1989616155624

Nikita Z:     199.51429748535

Getting Position of Enemy     5

Enemy X:     -93.561325073242

Enemy Y:     0.98000001907349

Enemy Z:     142.15086364746

Getting Position of Enemy     6

Enemy X:     -73.01343536377

Enemy Y:     0.98040544986725

Enemy Z:     100.40016174316

Getting Position of Enemy     7

Enemy X:     -127.0439453125

Enemy Y:     0.98101043701172

Enemy Z:     178.62501525879

Getting Position of Enemy     8

Enemy X:     -69.382301330566

Enemy Y:     0.98003792762756

Enemy Z:     98.895523071289

Getting Position of Enemy     9

Enemy X:     -94.973983764648

Enemy Y:     0.98000001907349

Enemy Z:     148.33338928223

Getting Position of Enemy     10

Enemy X:     -77.387153625488

Enemy Y:     0.99567884206772

Enemy Z:     90.933670043945

Getting Position of Enemy     11

Enemy X:     -91.799133300781

Enemy Y:     0.98000001907349

Enemy Z:     147.32833862305

Getting Position of Enemy     12

Enemy X:     -169.74723815918

Enemy Y:     0.98040544986725

Enemy Z:     203.3201751709

Getting Position of Enemy     13

Enemy X:     -77.210525512695

Enemy Y:     0.98101043701172

Enemy Z:     98.194877624512

Getting Position of Enemy     14

Enemy X:     -67.164535522461

Enemy Y:     0.98016083240509

Enemy Z:     108.30587005615

Getting Position of Enemy     15

Enemy X:     -163.95088195801

Enemy Y:     0.98003792762756

Enemy Z:     201.88360595703

Collide with Enemy     15

But unfortunately when the object gets killed, the game still crashes. Could it be because the kill command is in the function that checks if the remote droid is alive? (if nikitaUnit then)

EDIT: Nope, it still crashes when I move the killObject outside the function and initiate it with a timer. My second guess would be the for loop as it continues to run even after the collision happened and the remote droid is destroyed.

New BF2Log.txt

Hidden/Spoiler:

nikitaUnit:    userdata: 07FF1C40

Nikita X:     -107.66374206543

Nikita Y:     1.1990495920181

Nikita Z:     136.84364318848

Getting Position of Enemy     5

Enemy X:     -175.91766357422

Enemy Y:     0.99538546800613

Enemy Z:     179.9130859375

Getting Position of Enemy     6

Enemy X:     -85.346557617188

Enemy Y:     0.99532562494278

Enemy Z:     91.383529663086

Getting Position of Enemy     7

Enemy X:     -173.42977905273

Enemy Y:     0.99562096595764

Enemy Z:     193.52914428711

Getting Position of Enemy     8

Enemy X:     -77.729270935059

Enemy Y:     0.99573642015457

Enemy Z:     89.408149719238

Getting Position of Enemy     9

Enemy X:     -108.67774963379

Enemy Y:     0.99544489383698

Enemy Z:     138.40371704102

Collide with Enemy     9

Getting Position of Enemy     10

Enemy X:     -105.54786682129

Enemy Y:     0.99508261680603

Enemy Z:     144.50973510742

Getting Position of Enemy     11

Enemy X:     -137.38536071777

Enemy Y:     0.99550396203995

Enemy Z:     177.45980834961

Getting Position of Enemy     12

Enemy X:     -134.85348510742

Enemy Y:     0.99062728881836

Enemy Z:     173.28887939453

Getting Position of Enemy     13

Enemy X:     -68.723876953125

Enemy Y:     0.98000001907349

Enemy Z:     97.07315826416

Getting Position of Enemy     14

Enemy X:     -178.24624633789

Enemy Y:     0.98000001907349

Enemy Z:     178.82249450684

Getting Position of Enemy     15

Enemy X:     -178.62768554688

Enemy Y:     0.99556261301041

Enemy Z:     190.33854675293

Getting Position of Enemy     16

Enemy X:     -178.27635192871

Enemy Y:     0.98000001907349

Enemy Z:     184.02867126465

nikitaUnit:    userdata: 07FF1C40

Posted: **Wed Apr 14, 2021 2:35 pm**

I see another mistake. You're not actually checking if nikita is alive when the timer elapses. nikitaUnit is a copy of the objectData that you made during the OnCharacterDispenseControllable event; it won't update itself. So you're checking nikitaUnit when the timer elapses, but what you're actually checking is if nikita was alive immediately after the controllable was dispensed, because that's when you copied the objectData into nikitaUnit.

You should probably use nikitaPtr as a global variable instead, found with GetObjectPtr(controllable). Then when the timer elapses, you'd somehow need to use the nikitaPtr to update the nikitaUnit. I don't know what functions go backwards from the objectPtr to the objectData, but that seems like the way to do it.

Edit: I wonder if IsObjectAlive() uses the objectPtr. Then you could get nikitaUnit and nikitaPtr in the OnCharacterDispenseCollectable. And then you'd begin OnTimerElapse by checking IsObjectAlive(nikitaPtr) to make sure that the nikitaUnit is still usable. Doing stuff like GetWorldPosition(nikitaUnit) on a dead nikita might be the source of the crash.

eg

Code: Select all

nikitaUnit = nil
nikitaPtr = nil

OnCharacterDispenseControllable(
	function(player, controllable)
		if GetEntityClass(controllable) == FindEntityClass("rep_weap_inf_remotedroid_ord") then
			nikitaUnit = controllable
			nikitaPtr = GetObjectPtr(controllable)
			
			StartTimer("NikitaPosUpdate")
		end
	end
)

OnTimerElapse(
	function(timer)
		if nikitaUnit and nikitaPtr then -- error check
			if IsObjectAlive(nikitaPtr) then -- check that the object is alive
			
				-- code in here should be able to use nikitaUnit with no problems
				
			end
		end
		
		SetTimerValue("NikitaPosUpdate", 1)
		StartTimer("NikitaPosUpdate")
	end,
	"NikitaPosUpdate"
)

Also make sure you have some way of destroying the timer through code. I've suspected for a while that timers crash instant action playlists when you don't destroy them because the game doesn't clean them up properly after the mission. But I've haven't really tested the idea; it's just something that's given me problems before.

edit2: You're probably right that the for loop is a problem too. But you can just add a break after the KillObject to stop it looping.

Posted: **Wed Apr 14, 2021 5:08 pm**

Thanks for the input Sporadia. I redid some parts of the code and added a variable that checks if a collision is happening or not. But I think the important part was the Ptr and the break of the for loop.

This is the code I am using and it works with several remote droids in a row.

Code: Select all

nikitaUnit = nil
nikitaPtr = nil
nikitaCollision = false

CreateTimer("NikitaPosUpdate")
SetTimerValue("NikitaPosUpdate", 1)

CreateTimer("NikitaRefresh")
SetTimerValue("NikitaRefresh", 1.1)

OnCharacterDispenseControllable(
   function(player, controllable)
		if GetEntityClass(controllable) == FindEntityClass("rep_weap_inf_remotedroid_ord") then
			nikitaUnit = controllable
			nikitaPtr = GetObjectPtr(controllable)
			print("MGS_Rocket_Script: nikitaPtr:", nikitaPtr)
			StartTimer("NikitaPosUpdate")
		end
	end
)

OnTimerElapse(
	function(timer)
		if nikitaUnit and nikitaPtr then
			if IsObjectAlive(nikitaPtr) then
				print("MGS_Rocket_Script: nikitaUnit:", nikitaUnit)
				print("MGS_Rocket_Script: nikitaPtr:", nikitaPtr)
			
				nikitaX,nikitaY,nikitaZ = GetWorldPosition(nikitaUnit)
				print("MGS_Rocket_Script: Nikita X ", nikitaX)
				print("MGS_Rocket_Script: Nikita Z ", nikitaZ)
				
				local teamSize = GetTeamSize(2)
				
				for i = 0, teamSize - 1 do
					enemyIndex = GetTeamMember(2,i)
					print("MGS_Rocket_Script: Getting Position of Enemy ", enemyIndex)
					enemyX,enemyY,enemyZ = GetWorldPosition(GetCharacterUnit(enemyIndex))
					print("MGS_Rocket_Script: Enemy X ", enemyX)
					print("MGS_Rocket_Script: Enemy Z ", enemyZ)
					
					local xDifference = math.abs(enemyX - nikitaX)
					local zDifference = math.abs(enemyZ - nikitaZ)
					
					if (xDifference <= 2) and (zDifference <= 2) then
						print("MGS_Rocket_Script: Collide with Enemy ", enemyIndex)
						nikitaCollision = true
						KillObject(nikitaUnit)
						StartTimer("NikitaRefresh")
						break
					end
				end
			end
		end 
		
		if nikitaCollision == false then
			SetTimerValue("NikitaPosUpdate", 1)
			StartTimer("NikitaPosUpdate")
			print("MGS_Rocket_Script: Restart NikitaPosUpdate Timer")
		end
	end,
	"NikitaPosUpdate"
)

OnTimerElapse(
	function(timer)
		print("MGS_Rocket_Script: Restart Nikita script")
		nikitaCollision = false
	end,
	"NikitaRefresh"
)

Sometimes, although seldom, the droid doesn't explode upon collision and is therefore stuck. It doesn't crash anymore, but I get this error:

Hidden/Spoiler:

...

MGS_Rocket_Script: Getting Position of Enemy     6

MGS_Rocket_Script: Enemy X     -112.08446502686

MGS_Rocket_Script: Enemy Z     144.57516479492

MGS_Rocket_Script: Collide with Enemy     6

MGS_Rocket_Script: Restart Nikita script

MGS_Rocket_Script: nikitaPtr:    userdata: 07DE0CC0

MGS_Rocket_Script: nikitaUnit:    userdata: 07DE0CC0

MGS_Rocket_Script: nikitaPtr:    userdata: 07DE0CC0

MGS_Rocket_Script: Nikita X     -211.57345581055

MGS_Rocket_Script: Nikita Z     131.76643371582

MGS_Rocket_Script: Getting Position of Enemy     5

MGS_Rocket_Script: Enemy X     -122.76979827881

MGS_Rocket_Script: Enemy Z     140.19921875

MGS_Rocket_Script: Getting Position of Enemy     6

MGS_Rocket_Script: Enemy X     -120.69888305664

MGS_Rocket_Script: Enemy Z     139.28523254395

MGS_Rocket_Script: Getting Position of Enemy     7

Message Severity: 3

C:\Battlefront2\main\Battlefront2\Source\LuaHelper.cpp(312)

CallProc failed: bad argument #1 to `GetWorldPosition' (string expected, got nil)

stack traceback:

	[C]: in function `GetWorldPosition'

	(none): in function <(none):69>

Usually the for loop stops right at the red marked line where the collision happens, but here it goes on. I think this has something to do with the relatively long timer intervall of 1 sec

Posted: **Wed Apr 14, 2021 7:42 pm**

You could just edit the com_weap_inf_remotedroid_destruct.ODF and change MaxPressedTime to 0.1 so it explodes as soon as you hit the trigger.

-= Gametoast.com =-

Remote Droid that detonates on impact

Remote Droid that detonates on impact

Re: Remote Droid that detonates on impact

Re: Remote Droid that detonates on impact

Re: Remote Droid that detonates on impact

Re: Remote Droid that detonates on impact

Re: Remote Droid that detonates on impact