AFSM (File Format)

The AFSM format controls AI behavior; it stands for AI Finite State Machine. AI-controlled creatures have a limited number of possible states they can be in. The AFSM file defines those states, and what triggers can cause it to advance to another state.

This file format is almost completely documented We should have a list of possible states and trigger conditions and a short explanation of what they generally do on this page somewhere. Also, the float settings on conditions is unknown.

Format

Header

The format first defines a list of states, then defines each trigger attached to each state. There are no state/trigger type IDs; rather, the name string itself is used as an identifier to fetch the corresponding AI function. It starts with a short header listing each state and then providing a trigger count. Note that the trigger count isn't actually used to parse the file; it's present merely because the game uses it to allocate space for each trigger ahead of time.

Type	Count	Description
long	1	State count (SC)
string	SC	State names (each zero-terminated)
long	1	Trigger count

State Triggers

Following that, it iterates through each state, defining the triggers associated with each one. Triggers are composed of a target state index and a number of conditions; when all the conditions associated with a trigger are satisfied, it advances to the targeted state. The state trigger definitions are structured like this:

Type	Count	Description
long	1	Trigger count (TC)
Trigger	TC	Triggers

Trigger

Type	Count	Description
long	1	Condition count (CC)
Trigger condition	CC	Conditions

Condition

Type	Count	Description
string	1	Condition name
float	1	Unknown (possibly AI function parameter)
long	1	Target state index (note: this is ONLY present on the first condition for each trigger!)