Home For Builders Scripting Tutorials Using Area Events

Using Area Events

Intended Audience:
By David Gaider

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Keep in mind that when you create scripts for the area events (or, indeed, for the module events) that the default 'performer' of any action-related commands is the area, itself.

If you refer to OBJECT_SELF, you are referring to the area object. If you use an action-related command such as ActionMoveToObject without using AssignCommand to firs send that command to a creature object, you are telling the area to move (which it, of course, cannot). Simply keep this in mind as you code, so you can differentiate between telling the area what to do and telling things within the area what to do.

Area Events Listing

Event: OnEnter, triggered by: something (not necessarily a player character) has entered the area, what triggered it? Use GetEnteringObject() to return the object that has entered the area.

An example: Let's say you wanted to set an object variable called "PC_Entered" that was on the area whenever a player character entered the area (with the object being equal to the PC)... and then send a UserDefined event to a particular creature in the area with the unique tag "HUNTER" (I could then have an OnUserDefined event for that creature to come looking for the PC). You would place the following script in the OnEnter event for that area -

NWScript:
void main() { object oEntering = GetEnteringObject(); object oMonster = GetObjectByTag("HUNTER"); // if the entering object is a player character if (GetIsPC(oEntering)) { // set the object variable on the area to equal the PC SetLocalObject(OBJECT_SELF, "PC_Entered", oEntering); // send a UserDefinedEvent number 100 to the monster SignalEvent(oMonster, EventUserDefined(100)); } }

Event: OnExit, triggered by: someone has left the current area, what triggered it? Use GetExitingObject().

An example: Let's take the same script above and set the "PC_Entered" area-set variable to an invalid object if the PC leaves. Let's also check if the exiting object is the monster from above (chasing the PC, no doubt)... and if it is, tell him to return to his cave (where there is a waypoint laid down with the tag "HUNTER_CAVE") -

NWScript:
void main() { object oExiting = GetExitingObject(); object oMonster = GetObjectByTag("HUNTER"); object oCave = GetObjectByTag("HUNTER_CAVE"); // if the exiting object is a player character if (GetIsPC(oExiting)) { // set the area-set variable to an invalid object SetLocalObject(OBJECT_SELF, "PC_Entered", OBJECT_INVALID); } // if the exiting object is the monster if (oExiting == oMonster) { // tell him to stop what he's currently doing AssignCommand(oMonster, ClearAllActions()); // tell him to move back to his cave waypoint AssignCommand(oMonster, ActionMoveToObject(oCave)); } }

Event: OnHeartbeat, triggered by: Nothing is required to trigger the heartbeat... any script that is placed here will be automatically triggered once every 6 seconds. As with the module events, be careful of placing scripts in here that would run constantly.

Event: OnUserDefined, triggered by: This can only be triggered by someone using the SendSignal command to specifically send a UserDefined event to the area object (usually via the GetArea command or GetObjectByTag using the area's tag).