State Machines (also known as Finite State Machines or FSM) are the most basic form of AI.
As its name implies, an entity can be in just one state at a time and can only transition to another state which is linked to the current one.
For example, a very simple State Machine could define the behavior of a guard. We could define two states:
- Attacking the Player
The guard would start in the Patrolling state and only transition to the Attacking Player state if the player is in sight.