wave6-ecs-state-machine-design

To choose an ECS state representation, evaluate your state count, transition frequency, and query-filtering needs. Unity DOTS state machines typically use an enum field, an IEnableableComponent, or structural add/remove patterns based on these performance and correctness factors.

The best way to manage binary state transitions in Unity ECS is using an IEnableableComponent. It provides efficient bit flips for state changes and allows downstream systems to easily query-filter by active states without triggering expensive structural changes.

Use structural add and remove for Unity DOTS state changes when managing lifecycle-based transitions where entities move between mutually exclusive states. This pattern triggers chunk moves, making it suitable when state changes are infrequent and require strict architectural separation.

Structural changes affect performance in Unity ECS state machines because adding or removing components triggers chunk moves. While enum field writes and enableable bit flips are relatively cheap, structural changes incur higher costs when state transition frequency is high.

You can use an enum field for gameplay AI state logic, but it limits query filtering. Downstream systems must read the field value directly rather than filtering through Unity ECS query architecture, making it better for high transition rates with few states.

Unity DOTS state machine performance heavily depends on how systems filter by state. IEnableableComponent and structural patterns allow native query filtering, while enum fields require systems to iterate and check values, impacting overall query efficiency.