State Machines In Unity

A state machine controls which behavior is active at any time. Only one state runs at a time. When conditions change, the machine switches to a different state.

• Player standing still - Idle state
• Player presses arrow - Walk state
• Player presses space - Jump state

Basic State Machine Structure

First, create an enum to list all possible states.

Then create a manager script that switches between states.

Output:

Complete Player State Machine Example

Here's a full working example for a player character

State Machine with Separate Classes

For complex games, create separate classes for each state.

And the state machine manager:

When to Use a State Machine

Good for

• Player behavior (idle, walk, jump, attack).
• Enemy AI (patrol, chase, attack, flee).
• Game states (menu, playing, paused, game over).
• Any system with multiple modes or transitions.

Not needed for

• Simple moving platforms.
• Static obstacles.
• Single-state objects (no behavior change).
• Very basic scripts with no state switching.