GetDetected returning 0 when NPC is close by

[irswat]

What causes an NPC to return 0 or 1 when using GetDetected? I'm making a sniper mod and I have these custom snipers on sniper towers and I wrote this nifty little script so that the snipers attack from as far away as possible, yet it isnt until I get practically right next to the sniper tower-approx 2000-4000 units away-that the snipers react and start attacking the player.

I have some debug code in there using OnDetect and the player will be in range of the sniper, but the sniper is throwing the OnDetect==0 flag, or not detecting the player in other words. I cant help but wonder if this is a line of sight issue as I heard LOS is calculated from the feet! If that is true then that is dumb because feet don't have eyes. How can I overcome this issue?

[jazzisparis]

The detection mechanism in the game and how exactly is detection calculated is not fully-understood and is at least partially hardcoded. You can force an NPC to search for the player (SendAssaultAlarm), but you can't force it to detect the player. At such long ranges you speak of, there is no chance an NPC will detect the player, even in daytime and with a clear LOS.

I suggest a "simulated" detection process, and UseWeapon to force attack. Consider the following script:

scn	SniperModScript



ref	rSniper

short	iEvalRange

short	iRange

short	bLooking

short	iEvalDetection

short	bDetected

float	fChance



begin GameMode



	if iEvalRange == 0

		set iRange to GetDistance player

		if iRange < 8000

			if bLooking == 0

				set bLooking to 1

				Look player

			endif

			if iEvalDetection == 0

				set iEvalDetection to 300

				if GetLOS player == 0

					set bDetected to 0

				elseif bDetected == 0

					set fChance to 20 + ((8000 - iRange) / 400)

					if player.IsSneaking

						set fChance to fChance * (1 - (player.GetAV Sneak / 200))

					endif

					if (GameHour > 19) || (GameHour < 5)

						set fChance to fChance / 2

					endif

					set bDetected to (fChance > GetRandomPercent)

				endif

				if bDetected != (GetCurrentAIPackage == 33)

					if bDetected

						if rSniper == 0

							set rSniper to GetSelf

						endif

						UseWeapon WeapNVGhillieSniperRifle rSniper player -1 0 0

					else

						RemoveScriptPackage

						EVP

					endif

				endif

			else

				set iEvalDetection to iEvalDetection - 1

			endif

		else

			set iEvalRange to 600

			set iEvalDetection to 0

			if bDetected

				set bDetected to 0

				RemoveScriptPackage

				EVP

			endif

			if bLooking

				set bLooking to 0

				StopLook

			endif

		endif

	else

		set iEvalRange to iEvalRange - 1

	endif



end

What happens here:

Every 10 seconds, the script checks if the player is within 8000 game units.

If so, it runs a detection check every five seconds, based on LOS, distance from the player, time of day, whether the player is sneaking, the player's sneak skill, and finally a random percent. The calculated detection chance is from 5 to 40% (this seems realistic and balanced enough to me. You can, of course, tweak it - just remember it is re-evaluated every 5 seconds). If successful, the NPC will start firing at the player, and will not cease until losing LOS - at which point detection checks will resume.

Edited March 11, 2014 by jazzisparis

[irswat]

thanks a lot JIP. You will be getting huge ups when I release this mod. Will it make a difference if I use this with a guard package attached to reference x marker? I have aggro radius at 20000, combat radius at 20000 with 10x max range multi as we discussed, guard radius at 20000, guard location at 0.

After looking at your code I think I was using GetDistance the wrong way, as I was using GetSelf the wrong way! Thanks so much man

Edited March 11, 2014 by irswat

[devinpatterson]

I suggest a "simulated" detection process, and UseWeapon to force attack. Consider the following script:

 

 

What happens here:

Every 10 seconds, the script checks if the player is within 8000 game units.

If so, it runs a detection check every five seconds, based on LOS, distance from the player, time of day, whether the player is sneaking, the player's sneak skill, and finally a random percent. The calculated detection chance is from 5 to 40% (this seems realistic and balanced enough to me. You can, of course, tweak it - just remember it is re-evaluated every 5 seconds). If successful, the NPC will start firing at the player, and will not cease until losing LOS - at which point detection checks will resume.

Great script Jazzisparis, it will be awesome to have a mechanic that mimics real sniping. But I was curious, (as a non scripting guy) you mentioned the script checks every 10 seconds if the player is <= 8000 units, and also re-evaluated every 5 seconds. I didn't see a timer in the code, is this a quest script (set at default 5)? And the 5 vs the 10 second just a mistype?

[irswat]

JIP why do you use -1 with UseWeapon what does that accomplish? What parameters does GetRandomPercent take? (E.G. a low number, high number?)

[jazzisparis]

Will it make a difference if I use this with a guard package attached to reference x marker? I have aggro radius at 20000, combat radius at 20000 with 10x max range multi as we discussed, guard radius at 20000, guard location at 0.

It won't interfere with the script. You can leave it if you want, but it won't make any difference.

 

 

Great script Jazzisparis, it will be awesome to have a mechanic that mimics real sniping. But I was curious, (as a non scripting guy) you mentioned the script checks every 10 seconds if the player is <= 8000 units, and also re-evaluated every 5 seconds. I didn't see a timer in the code, is this a quest script (set at default 5)? And the 5 vs the 10 second just a mistype?

iEvalRange and iEvalDetection act as timers here. Since object/effect scripts iterate every frame (optimally, 60 times/sec), I prefer counting iterations, instead of measuring actual real-time passage.

 

 

JIP why do you use -1 with UseWeapon what does that accomplish? What parameters does GetRandomPercent take? (E.G. a low number, high number?)

UseWeapon expects a positive integer. Feeding it -1 will make it fire to infinity, until halted by RemoveScriptPackage+EVP.

GetRandomPercent takes no parameters and return a random integer in the range of 0-99.

[irswat]

thank you