dots-baking-patterns

DOTS Baking — Senior Patterns

Baking translates authoring-scene GameObjects into runtime entities. Get baking wrong and you get incremental-bake misses, runtime null references, archetype churn, and broken Live Baking — none of which surface until much later.

Intent

Convert authoring state to entity state once, deterministically, and with explicit dependencies. Baking is not "Awake for entities" — it runs in the editor at conversion time, not at runtime.

Use when

• Translating MonoBehaviour authoring into IComponentData
• Producing prefab Entity references for runtime instantiation
• Generating additional entities from one authoring component (e.g. one image → N pixel entities)
• Sharing static lookup data (build a BlobAssetReference<T> at bake time)

Avoid when

• Implementing runtime logic. Bakers run only in editor / build conversion. They never tick.
• Mutating asset state. Bakers must be pure read-from-authoring → write-to-entity.
• Hidden side effects (logging that depends on bake order, file writes, etc.).

Senior pattern

public class EnergyShieldAuthoring : MonoBehaviour
{
    public int MaxHitPoints;
    public float RechargeDelay;
    public float RechargeRate;
    public GameObject Prefab;           // referenced prefab
    public Mesh Mesh;                   // referenced asset

    public class Baker : Baker<EnergyShieldAuthoring>
    {
        public override void Bake(EnergyShieldAuthoring authoring)
        {
            // 1. Declare dependencies BEFORE early-out null checks.
            //    A null ref may mean "missing asset" — bake must re-run when it returns.
            DependsOn(authoring.Mesh);

            // 2. Choose TransformUsageFlags deliberately:
            //    - None        → no transform components, smallest archetype
            //    - Renderable  → static world-space transform only
            //    - Dynamic     → full LocalTransform + Parent (movable at runtime)
            //    - ManualOverride → opt out; you add the transform components yourself
            var entity = GetEntity(TransformUsageFlags.None);

            if (authoring.Mesh == null) return;

            // 3. Read sibling GameObject components THROUGH the Baker — never via
            //    authoring.transform — so dependencies are tracked.
            var t = GetComponent<Transform>();

            AddComponent(entity, new EnergyShield {
                HitPoints     = authoring.MaxHitPoints,
                MaxHitPoints  = authoring.MaxHitPoints,
                RechargeDelay = authoring.RechargeDelay,
                RechargeRate  = authoring.RechargeRate,
                // 4. Prefab references go through GetEntity, which converts them
                //    AND registers the dependency in one call.
                Prefab        = GetEntity(authoring.Prefab, TransformUsageFlags.Dynamic),
                VertexCount   = authoring.Mesh.vertexCount,
            });
        }
    }
}