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 transition to another state.

This file format is almost completely documented We should have a list of possible states and triggers 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 the triggers for each transition 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 Transitions

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

Type	Count	Description
long	1	Transition count (TC)
Transition	TC	Transitions

Transitions

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

Trigger

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