Thoughts on triggers

On the RND test, here are some thoughts on triggers.

Triggers are broadcast by a function. Triggers may have a targeted object/instance. In order to target any potential object, they’re put into a Family, which I’ll refer to as f_trigger_receiver (f_tr, for short).

There are 2 parts to triggers. The ‘main’ logic, and the ‘map’ logic. The main logic handles generic logic of triggers.

Main logic


The Family for all trigger receivers. Requires f_name, and f_receivedtrigger variables. f_name is the name of the entity which a trigger will use to refer to this instance. f_receivedtrigger is the string identifying the trigger that has been sent out.

On player GridMove reach target

Fired every time the player moves into a tile. This queries if a trigger area was stepped on.

Also, the player must have a current_trigger variable which keeps track of the trigger area it is on at any given time. This prevents re-triggering when the trigger area covers adjacent tiles. Also, this allows to find out if the player has stepped out of a trigger.


A function which handles the send off to f_trigger_receiver. It accepts a trigger_name, and a trigger_target. The trigger_name is the identifier of the trigger. The trigger_target is a comma-delimited string that identifies the objects/instances that the trigger will be sent to. The f_trigger_receiver family is used in order to go across different object types.

Other interactions

Any other interactions deemed worthy of a trigger only has to call the BroadcastTrigger function, and feed it an object that can accept a trigger.

The RND test, for example, had broadcast an NPC interaction generically by feeding it trigger_name="npctalk", trigger_target="npc1". Then the trigger was broadcast only on npc1 and processed accordingly.

There are no  ‘global’ triggers (ie triggers must always have a target). If a ‘global’-like trigger is needed, it might be better to use the player’s mover token as that, since it’s as global as you’re going to get.

Map logic

Map logic refers to the map/room-specific stuff.

Typically, the triggers for a particular room are stored in a separate event sheet (which I call scripts).

Time triggers

I put the time triggers in the map because it’s more specific to the map/mission. I still call BroadcastTrigger, but the trigger_name is specific to the map, of course.

Time triggers include ‘per-tick’ or any kind of time-related triggers.


Some instances need to init themselves before going into play. For example, a waypoint traveller needs to init the first waypoint index. This is done using the post_tmx boolean check, which is basically a switch that tells that the TMX has been completely read, and all objects have been created (and thus referenceable).

Other triggers and functions

Any other kind of triggers, whether they’re from FSM or TOWT, can be put in the map logic script. In the RND test, I’ve put in unique FSM states (eg “reachpath”) to put it in a special state so that the rest of AI can contextualise itself.

Map-specific functions are put here as well.






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