Any shortcuts to detect avatars entering a parcel?

[GTASkinCentral]

Hello!

Does anyone have any shortcuts that will allow me to detect new avatars within a parcel? Every time someone enters the parcel, I want to trigger a number of events. I have thought about having a timer to compare two lists, an archived list and a recent list.

Any help is much appreciated!

[Rolig Loon]

That's the strategy I would use. 

list WhoIsNew(){    list AllAvs = llGetAgentList(AGENT_LIST_PARCEL,[]);    list NewAvs;    integer i = llGetListLength(AllAvs);    while(i--)    {	if ( !~llListFindList(gHereAlready,llList2List(AllAvs,i,i)) )        {            NewAvs += llList2List(AllAvs,i,i);        }    }    gHereAlready = AllAvs;    return NewAvs;}

 

 

That makes use of the ListXnotY routine in the wiki at http://wiki.secondlife.com/wiki/ListXnotY.  Just remember to declare the global list gHereAlready.  Fire that routine maybe once a minute with your timer.  And if you don't care who the new people are, just make the routine return TRUE or FALSE instead of the list.

 

[GTASkinCentral]

I see, would you be able to put that into context for me?

 

If a new avatar is detected do one thing, else, do nothing?

[Rolig Loon]

As a simple Here/NotHere switch?  As I suggested, return TRUE/FALSE instead of the avatar list, as in

list gHereAlready;integer WhoIsNew(){    list AllAvs = llGetAgentList(AGENT_LIST_PARCEL,[]);    list NewAvs;    integer IsHere;    integer i = llGetListLength(AllAvs);    while(i--)    {	if ( !~llListFindList(gHereAlready,llList2List(AllAvs,i,i)) )        {            NewAvs += llList2List(AllAvs,i,i);            IsHere = TRUE;        }    }    gHereAlready = AllAvs;    return IsHere;}default{    state_entry()    {        llSetTimerEvent(60.0);    }    timer()    {        if(WhoIsNew())        {            // Set off flares, e-mail the owner, start playing a Sousa march ...        }        else        {            llInstantMessage(llGetOwner(),"Still no new visitors <sigh>");        }    }}

 

 

 

 

[Dora Gustafson]

In the OP I don't read any request for identifying the agents
In that case the task becomes simple

list agents;default{    state_entry()    {        agents = llGetAgentList(  AGENT_LIST_PARCEL, []);        llSetTimerEvent( 4.0);    }    timer()    {        list L = llGetAgentList(  AGENT_LIST_PARCEL, []);        if ( llGetListLength( L) > llGetListLength( agents) )        {            // the population has increased, take appropriate action        }        agents = L;    }}

This approach will not trigger when the number of entries equals the number of exits in one time window
That may or may not be a problem

:smileysurprised::smileyvery-happy:

[Miranda Umino]

It depends of the value of the timer in parameter of llSetTimerEvent .
If the value is big ( as for rollig where the value is 60 seconds ) , probability to get both people in and out :

First tick : there are 15 avatars .
between the first tick and second tick , there are one avatar who leaves , and one avatar who enters 
Second tick : there are always 15 avatars . 

If the value of the timer is short , probabilty that the new list is equal with the old list is big .
And we may optimize this , avoiding to call too much llfindlist.

To check quickly if the lists are the same, we may call llFindList with the full new list and the ful old list , and compare their length

The idea is there :

IN PSEUDOCODEif ( llListFindList(beforeList, nowList) == 0 ){	if ( llGetListLength(beforeList) == llGetListLength(nowList))	{	// NO UPDATE OF OLDLIST WITH NEWLIST. And New avatars is EMPTY	}	else	{	// UPDATE OLDLIST WITH NEWLIST . And New avatars is EMPTY	}}else{// WE DON T KNOW IF New Avatars is empty or not , WE NEED TO ITERATE THE LISTS}

 

 

list gHereAlready ;integer WhoIsNew( ){   list AllAvs = llGetAgentList(AGENT_LIST_PARCEL,[]);// if this test > 0 , so the whole AllAvs list is included in gHereAlready // with one block    if ( llListFindList(gHereAlready , AllAvs ) >= 0 )    {      // if lists have different lengths ,      // AllAvs is included in gHereAlready      // It means there are some people who have left     // So we need to update gHereAlready         if ( llGetListLength(gHereAlready) != llGetListLength(AllAvs))        {            gHereAlready = AllAvs;        }     // if lists have equal lengths     // gHereAlready is already equal to AllAvs     // We non t need to update it.     // This is what will happen the most often     // In the 2 cases , we may return directly without doing a loop     // because we know the AllAvs  is included in gHereAlready         return FALSE;    }    if ( llGetListLength(gHereAlready) == 0 )    {        gHereAlready = AllAvs;        return TRUE;    }                list NewAvs;    integer IsHere;    integer i = llGetListLength(AllAvs);    key k;    while(i--)    {        if ( !~llListFindList(gHereAlready,llList2List(AllAvs,i,i)) )        {            NewAvs += llList2List(AllAvs,i,i);            IsHere = TRUE;        }    }    gHereAlready = AllAvs;    return IsHere;}

 

It won t optimize a lot of . It depends of the number of avatars .

Around 35-45 avatars , i ve got around 40-60 ms  with the original version , and  25-35 ms with this version.

 

[Rolig Loon]

Nice, Miranda.  I like that.