Question Basic questions about ECS

Hey!

So I'm pretty new to this and still trying to get my head around how to build my project.
I am trying to create the following:

In my "regular" Scene:

• GameManager GameObject
• Player GameObject (1-4 players)
• Planet GameObject (4-20 planets)

Then in the subscene I want to create the following entities:

• Player Entities
• Planet Entities
• Unit Entities

So player and planet objects should exist both in the normal scene as GO, and an entity in the subscene with components relevant for ECS.
So I use ECS only to control the units (trajectories calculated etc.).
The movement of the planets, rendering of the planets, events of the players etc. still run with Monobehaviour / GameObjects.
According to all the tutorials on the Internet, I should now create a subscene and create all the necessary entities via baking from authoring GO.
This works fine for me.
e.g.:

Code (CSharp):

1.  
2. class PlanetAuthoring : Monobehaviour
3. {
4.     // vars
5.  
6.     public GameObject unitPrefab;
7. }
8.  
9. public class PlanetBaker : Baker<PlanetAuthoring>
10. {
11.     public override void Bake(PlanetAuthoring authoring)
12.     {
13.         // create components with authoring.vars
14.  
15.             AddComponent(new BasicUnitSpawner{
16.                 UnitPrefab = GetEntity(authoring.unitPrefab)
17.             }
18.     }
19. }
20.  
21. public struct BasicUnitSpawner : IComponentData
22. {
23.     public Entity UnitPrefab;
24. }

The cool thing is that you I get the entity with GetEntity(authoring.unitPrefab) and then I can instantiate units from it later in a system.
But GetEntity() only works in the baker. And I don't want to manually set up my subscene to have X planets, but spawn them via GameManager after it is done generating other things.
So I try spawning player and planet Entities in the GameManager:

Code (CSharp):

1.  
2. public class GameBuilder : MonoBehaviour
3. {
4.     public int numberOfPlayers = 2;
5.     public int numberOfPlanets = 4;
6.     public List<Color> playerColors = new List<Color>();
7.     public GameObject planetPrefab;
8.     EntityManager entityManager;
9.     EntityArchetype playerArchetype;
10.  
11.  
12.     private void Start()
13.     {
14.         entityManager = World.DefaultGameObjectInjectionWorld.EntityManager;
15.         playerArchetype = entityManager.CreateArchetype(
16.             typeof(PlayerConfiguration)
17.             );
18.         GeneratePlayers(numberOfPlayers);
19.         GeneratePlanets(numberOfPlanets);
20.     }
21.  
22.  
23.     void GeneratePlayers(int numberOfPlayers)
24.     {
25.         for(int i = 0; i < numberOfPlayers; i++)
26.         {
27.             // Generate new Player Entity
28.             Entity playerEntity = entityManager.CreateEntity(playerArchetype);
29.             entityManager.SetComponentData(playerEntity, new PlayerConfiguration { playerColor = Color.red });
30.             entityManager.AddSharedComponent(playerEntity, new PlayerNumber { Value = i+1 });
31.         }
32.     }
33.  
34.  
35.     void GeneratePlanets(int numberOfPlanets)
36.     {
37.         for (int i = 0; i < numberOfPlanets; i++)
38.         {
39.             // HOW CREATE ENTITY FROM PREFAB...?
40.         }
41.     }
42. }
43.  

Because the player is a simple Entity without transforms or child entity hierarchies, I create a player Archtype and Instatiate from it. I can see my player entities getting generated.
So far so good.
But how can i convert my planetPrefab Gameobject to a Entity (like I did in the baker), so that I can call entityManager.Instantiate(prefab_as_entity); ?

And another question I have:
The player entities, that I spawn in my GameManager are not spawned in the subscene.. see image:

The two at the bottom are my player entities. Shouldnt they be in my UnitsEntitiesScene (subscene) ?
Or is this looking good so far?

Thanks for reading all this noob stuff ^^

 

I read that you could use something like this in previous ECS versions:

Code (CSharp):

1.        
2. BlobAssetStore blobAssetStore = new BlobAssetStore();
3. var settings = GameObjectConversionSettings.FromWorld(World.DefaultGameObjectInjectionWorld, blobAssetStore);
4. entityPrefab = GameObjectConversionUtility.ConvertGameObjectHierarchy(GOprefab, settings);
5.  

But I dont have GameObjectConversionUtility available in Unity.Entities?
I dont get how I can convert a GO Prefab to an Entity in the new DOTS 1.0

 

I'd also like to know this. I've seen examples using a "ConvertToEntity" component, and interfaces such as IConvertGameObjectToEntity but none of them exist after installing the latest versions of ECS

 

I endend up using one GameObject that has all my prefabs and that then gets baked to an entity having all prefabs converted to entities:

Code (CSharp):

1. using Unity.Entities;
2. using UnityEngine;
3.  
4. // This GO gets converted to an entity
5. public class EntityPrefabContainer : MonoBehaviour
6. {
7.     public GameObject unitPrefab;
8.     public GameObject planetPrefab;
9. }
10.  
11. // Baking the EntityPrefabContainer to an entity
12. public class EntityPrefabContainerBaker : Baker<EntityPrefabContainer>
13. {
14.     public override void Bake(EntityPrefabContainer authoring)
15.     {
16.         AddComponent(new CommonEntityPrefabs
17.         {
18.             UnitPrefab = GetEntity(authoring.unitPrefab),
19.             PlanetPrefab = GetEntity(authoring.planetPrefab)
20.         });
21.     }
22. }
23.  
24. // Use this component to Instantiate new entities from
25. public struct CommonEntityPrefabs : IComponentData
26. {
27.     public Entity UnitPrefab;
28.     public Entity PlanetPrefab;
29. }

You can then instantiate new entities from Mono like this:

Code (CSharp):

1. // Get EntityManager first
2. EntityManager entityManager = World.DefaultGameObjectInjectionWorld.EntityManager;
3.  
4. // Create query for entites with  "CommonEntityPrefabs" Component
5. EntityQuery q_CommonEntityPrefabs = entityManager.CreateEntityQuery(typeof(CommonEntityPrefabs));
6.  
7. // Get the entity that we baked from Mono earlier
8. Entity entityPrefabContainer;
9. var container = q_CommonEntityPrefabs.ToEntityArray(Unity.Collections.Allocator.Temp);
10. if (container.Length > 0){
11.     Debug.Log("Found Prefab Container Entity");
12.     entityPrefabContainer = container[0];
13.     container.Dispose();
14. }
15.  
16. // Get prefab
17. Entity planetEntityPrefab = entityManager.GetComponentData<CommonEntityPrefabs>(entityPrefabContainer).PlanetPrefab;
18.  
19. // Spawn prefab
20. Entity planetEntity = entityManager.Instantiate(planetEntityPrefab);