baker-authoring-conversion

Baker and Authoring Conversion

Intent

Convert designer-facing MonoBehaviour authoring data into unmanaged ECS components at subscene import time, with zero runtime conversion overhead.

Use When

Any ECS entity that originates from a Unity scene or prefab. All runtime components with inspector-configurable parameters require a Baker.

Avoid When

Runtime-only entities created entirely by code (e.g., spawned from a prefab) — no Baker needed for the spawned instance, only for the prefab source entity.

Senior Pattern

• Declare a public MonoBehaviour (XyzAuthoring) with inspector-visible fields.
• Nest a private class Baker : Baker<XyzAuthoring> inside it.
• In Bake(): call GetEntity(TransformUsageFlags.X) to obtain the entity, then AddComponent(entity, new XyzComponent { ... }).
• Convert editor units to runtime units at bake time (e.g., degrees → radians).
• For prefab entity references: GetEntity(authoring.PrefabField, TransformUsageFlags.Dynamic).
• Use TransformUsageFlags.Dynamic for moving entities, TransformUsageFlags.None for static/data-only entities.

Code Template

public class EnemyAuthoring : MonoBehaviour
{
    public float MoveSpeedDegreesPerSecond = 90f;
    public GameObject ProjectilePrefab;

    class Baker : Baker<EnemyAuthoring>
    {
        public override void Bake(EnemyAuthoring authoring)
        {
            var entity = GetEntity(TransformUsageFlags.Dynamic);
            AddComponent(entity, new EnemyMoveSpeed
            {
                RadiansPerSecond = math.radians(authoring.MoveSpeedDegreesPerSecond)
            });
            AddComponent(entity, new EnemyProjectileRef
            {
                Prefab = GetEntity(authoring.ProjectilePrefab, TransformUsageFlags.Dynamic)
            });
        }
    }
}

Anti-Patterns

• Doing unit conversion at runtime in OnUpdate instead of at bake time — wasted per-frame cost.
• Forgetting TransformUsageFlags.Dynamic on an entity that moves — missing LocalTransform at runtime, silent wrong behavior.
• Not calling GetEntity for a referenced prefab GameObject — the prefab won't be baked into an entity prefab reference.
• Storing state on the Baker instance — Baker is stateless per-bake, state is discarded after each call.
• Calling Resources.Load or doing file I/O inside Bake — baking must be deterministic and dependency-tracked.