[Opensim-users] Sensors are not detecting NPC avatars on git r/17830

[Justin Clark-Casey]

An NPC flag is already kept, so there's no need to do any useraccount lookups.

On reflection, I'm not sure that llGetOwnerKey() returning UUID.Zero for 'unowned' avatars is really a problem.  The 
case in which this already happens is if the key is malformed.  But if you have received this from a sensor you know 
that the uuid is valid.

Still, I think it would be good to have another more intuitive means of knowing a given agent is an NPC.  Possibly 
llGetAgentInfo() could return an AGENT_IS_OS_NPC in the flags.

As for sensing, I think I'll have to go with OS_NPC_SENSE_AS_AGENT (sorry for the long name, Chris).  I'm still not 
really convinced that this really makes sense but it's very difficult to say without having it in the wild.  The worse 
that can happen is that the majority of people writing NPC scripts will have to remember to set this flag.
>
> Just my 2 cents but, as far as actually detecting if an avatar is an NPC, instead of having llGetOwnerKey() return
> 00000000-0000-0000-0000-000000000000 (I'm assuming that is essentially what UUID.Zero is in the server code) would it be
> possible to do a simple check routine against the UUID's in the useraccounts table? If the ID does not exist then it
> must be an NPC; if it does exist then it's an AGENT? Not sure how efficient this would be though if the useraccounts
> table is rather large... Or perhaps put a flag (transparent to the viewer) on each NPC created and have the code check
> for this flag each time it needs to deal with a targeted NPC; if the flag is there then it's an NPC, and vice versa.
> Reason I ask is, it's not so much as the sensor having issues dealing with an avatar that has
> 00000000-0000-0000-0000-000000000000 for a UUID, but the rest of the code actually having to deal with that number for
> an avatar's key. Like a poseball script for example, most of them are coded to assume that no one is sitting on it if
> the avatar key is NULL_KEY, therefore I would think that it would really confuse the script if the NPC was directed to
> sit on the poseball and its key is 00000000-0000-0000-0000-000000000000 . This is just a simple example but I have ran
> into problems with more complex scripts that utilize a list of owners in order to determine if an avatar is able to have
> access to its functions and the avatar being NULL_KEY.
>
> I think having a OS_NPC_SHOW_AS_AGENT (or perhaps maybe OS_NPC_AS_AGENT just to keep things short and sweet? :) ) option
> to the npc create command would be a good idea and a handy option to keep compatibility with older sensor scripts
> (especially ones that are no mod and can't be changed to include the NPC type) if it would allow the NPC's actual UUID
> to be seen by script(s)?
>
>
> On 1/19/2012 5:57 PM, Justin Clark-Casey wrote:
>> This is indeed correct. It means that sensors using the LSL AGENT type will not detect NPCs. To detect an NPC you must
>> specify the currently OpenSim-only NPC constant. This has been true since 7518b07 (Fri Jan 6 22:35:06 2012).
>>
>> One reason for doing this is because the sensor limit is 16 and one doesn't want the return to be overwhelmed by NPCs.
>> It means that sensor using scripts not designed with NPCs in mind (both in the past and the future) won't work with
>> NPCs without alteration. It strikes me that sometimes this is a disadvantage (e.g. a light that should come on when it
>> detects any presence) but for other items an advantage (e.g. non-NPC aware radars that wouldn't be designed to pick
>> them up anyway).
>>
>> So one option is to change the default so that AGENT will pick up NPCs. However, this is a problem with the 16 avatar
>> sensor limit. Even if this is turned up, it might then cause script problems (e.g. ones designed to work with only 16
>> avatars).
>>
>> Another slightly messy option is to provide something like an OS_NPC_SHOW_AS_AGENT option to osNpcCreate() that will
>> show such NPCs as agents. I'm favouring this option right now.
>>
>> Either way, what is missing at the moment is a way to actually tell if a particular agent is an NPC. One possibility
>> is to make llGetOwnerKey() return an owned NPC's owner. For an unowned NPC, this would need to return UUID.Zero - I'm
>> not sure if there's a problem disambiguating between an unowned NPC and a situation where no entity with the ID is found.
> --
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Justin Clark-Casey (justincc)
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