How Get One Specific Entity ?

Hello,
I am trying to get data from one specific entity. But for this, I need entity first.
How to get an entity with, for example, ComponentTag like "ShipTag" ?

I tried [Inject] but it's not getting any data

Entity is created this way:

Code (CSharp):

1. var shipEntity = entityManager.CreateEntity(ComponentType.Create<Position>(),
2.                                                         ComponentType.Create<Rotation>(),
3.                                                         ComponentType.Create<MoveSpeed>(),
4.                                                         ComponentType.Create<RotationSpeed>(),
5.                                                         ComponentType.Create<CellId>(),
6.                                                         ComponentType.Create<ShipTag>(),
7.                                                         ComponentType.Create<PlayerInput>());

For example, I want this ship position(on stage I have only one ship), so I created ShipData :

Code (CSharp):

1. public struct ShipData
2.     {
3.         public int Length;
4.         [ReadOnly] public ComponentDataArray<Position> Positions;
5.         [ReadOnly] public ComponentDataArray<ShipTag> ShipTag;
6.     }

And trying to access it this way in regular Monobehaviour Script:

Code (CSharp):

1. [Inject]ShipData shipData;
2.  
3. void SpawnBullet()
4. {
5. ... Creating Bullet Archetype...
6.  
7. var bulletEntity = em.CreateEntity(bulletArchetype);
8. EntityManager.SetComponentData(bulletEntity, new Position { Value = shipData.Positions[0].Value });
9. }

Is there any easier way? for example GetEntities<ShipData>[0].Position ... or something else or maybe I am missing something.
Compiler says: That kind of entity doesn't exist... Why when I am calling this function after 3 seconds from game start (ShipEntity spawns from the beginning of the game)

 

You can use GetComponentFromData<Position>() and then retrieve the position using the ship Entity.

 

But how to get this ShipEntity, I need it in a different system which doesn't know about the ship. I was thinking of storing it in public variable during creation but for this, I need to access Bootstrap class which, in my opinion, is not the best way...

 

If this is for example, the Player Ship... Why not have a PlayerShipComponent added to only 1 ship in the game, and look for that in your other system? Components are cheap. They can be used as booleans.

 

Yes, Exactly, and how to do this? I found posts about GetEntityArray but it seems it is not supported anymore.

 

[Solved]
Should check boid example once again before asking (https://github.com/Unity-Technologi...arch?q=ComponentType&unscoped_q=ComponentType)

Code (CSharp):

1. var ship = GetComponentGroup(ComponentType.ReadOnly<ShipTag>(), ComponentType.ReadOnly<Position>());
2. var posArray = ship.GetComponentDataArray<Position>();
3. var spawnPosition = posArray[0].Value;

Works like a charm.

 

Is it not possible to have a PlayerSystem looking specifically for the PlayerComponent in your scenario?

 

Inside your system that needs to find other components:

Code (CSharp):

1.        
2.  
3. private ComponentGroup _playerGroup;
4.  
5.         protected override void OnCreateManager()
6.         {
7.             _playerGroup = GetComponentGroup(typeof(Player));
8.         }
9.  
10.         protected override JobHandle OnUpdate(JobHandle inputDeps)
11.         {
12.             var players = _playerGroup.GetEntityArray();
13.             var player = players.Length > 0 ? players[0] : Entity.Null;
14.             var moveJob = new MovementJob
15.             {
16.                 DeltaTime = Time.deltaTime,
17.                 Player = player
18.             };
19. ...
20.  
21.  

 

Thank you it's even shorter and safer.