OSSL Script Library/Persist NPC

2011-11-03T04:31:52Z

7Nqe93KzcT:

When a [http://www.sproutseo.com SEO service] simulator is restarted, any NPCs on that sim's regions will not automatically reappear. Much like dynamic textures, NPCs are a transient and non-persistant asset that is not stored in any database. So any scripts that controls an NPC will need to have a mechanism in place to detect wether an NPC is currently instantiated, and recreate it if it is not.

== Implementing NPC Persistence<br> ==

The [http://lslwiki.net/lslwiki/wakka.php?wakka=llKey2Name llKey2Name] function placed in a timer event is the tool I use to check whether an NPC is still present in-world. If this function returns an empty string, it can be assumed that the NPC is no longer rezzed, and must be recreated.

The following script is an example of the mechanism I make use of to accomplish this task. It has been kept to the bare minimum necessary to demonstrate the concept, and to manage the NPC it creates.

<br>

<source lang="lsl">// NPC Persistance Example created by Marcus Llewellyn.
// This script is in the Public Domain.

key npc = NULL_KEY;
string firstname = "Dwight";
string lastname = "Smith";
integer dead = FALSE;

default
{
state_entry() {
// Setup and rez the NPC.
key temp = (key)llGetObjectDesc();
if (llKey2Name(temp) != "") {
// An NPC matching the UUID stored in the object description
// already exists, so just retrieve the UUID.
npc = temp;
} else if (dead == FALSE) {
// Create a new instance of the NPC, record the UUID in the
// object's description, and set starting rotation. NPC
// rotation and location are inherited from the controlling
// object with an offset.
npc = osNpcCreate(firstname, lastname, llGetPos() + <1.0,0.0,0.0>, llGetOwner());
llSetObjectDesc((string)npc);
osNpcSetRot(npc, llGetRot() * (llEuler2Rot(<0, 0, 90> * DEG_TO_RAD)));
}
// Have the NPC say a greeting, and set up persistance timer and
// listen for commands.
osNpcSay(npc, firstname + " " + lastname + ", at your service.");
llSetTimerEvent(10);
llListen(0, "", NULL_KEY, "");

}

timer() {
// Our NPC UUID stored in the object description should match the
// UUID of our existing NPC. If it does not, we presume an untimely
// demise, and initiate resurrection by simply reseting our script.
key temp = (key)llGetObjectDesc();
if (llKey2Name(temp) == "" && dead == FALSE) {
llResetScript();
}
}

listen(integer channel, string name, key id, string msg) {
if (llToLower(msg) == "kill") {
// Kill the NPC, set a flag so it stays dead, and misquote
// John Donne.
osNpcSay(npc, "Send not to know for whom the bell tolls, it tolls for me!");
osNpcRemove(npc);
dead = TRUE;
} else if (llToLower(msg) == "start" && dead == TRUE) {
// Create a new instance of our NPC, and set flag for
// persistance checks.
npc = osNpcCreate(firstname, lastname, llGetPos() + <1.0,0.0,0.0>, llGetOwner());
llSetObjectDesc((string)npc);
osNpcSetRot(npc, llGetRot() * (llEuler2Rot(<0, 0, 90> * DEG_TO_RAD)));
osNpcSay(npc, firstname + " " + lastname + ", at your service.");
dead = FALSE;
} else if (llToLower(msg) == "start" && dead == FALSE) {
// Don't do anything significant if the NPC is still incarnate.
osNpcSay(npc, "I'm already alive, boss.");
}
}
}</source>

OpenSimulator - User contributions [en]

OSSL Script Library/Persist NPC