This is a simple artificial intelligence system that implements simple AI logic. The AI character has four states, among which the Idle state is always idle and motionless, and this can be used as your NPC. The "Follow" status allows you to keep following the player's movement. This can be used as your pet or for the need to follow. The Patrol state is the patrol state. When it detects a player, it will switch to the attack state and run towards and attack the player. This can be used as an enemy in your scene.