Cant Convert GameObject to Entity in 0.3 version

Hello Everyone,

I upgraded my project from entities 0.1 to 0.3.


my MonoBehaviour code is converting a prefab and instantiating it's entities x times.(got it from ECSSamples)

Code (CSharp):

1.  
2. players = new NativeArray<Entity>(pSkins.Length, Allocator.Persistent);
3. // Create entity prefab from the Player GameObject Prefab Architype once
4. var settings = GameObjectConversionSettings.FromWorld(World.DefaultGameObjectInjectionWorld, null); // Error Here
5. var prefab = GameObjectConversionUtility.ConvertGameObjectHierarchy(clientPlayerPrefabArchitype, settings);
6. var entityManager = World.DefaultGameObjectInjectionWorld.EntityManager;
7.  
8. // Efficiently instantiate a bunch of entities from the already converted entity prefab
9. entityManager.Instantiate(prefab, players);
10.  
11.  

The Error:

Code (CSharp):

1. ArgumentNullException: A valid BlobAssetStore must be passed to construct a BlobAssetComputationContext
2. Parameter name: blobAssetStore
3. Unity.Entities.BlobAssetComputationContext`2[TS,TB]..ctor (Unity.Entities.BlobAssetStore blobAssetStore, System.Int32 initialCapacity, Unity.Collections.Allocator allocator) (at Library/PackageCache/com.unity.entities@0.3.0-preview.4/Unity.Entities.Hybrid/GameObjectConversion/BlobAssetComputationContext.cs:31)
4. Unity.Physics.Authoring.BeginColliderConversionSystem.OnUpdate () (at Library/PackageCache/com.unity.physics@0.2.5-preview/Unity.Physics.Hybrid/Conversion/BeginColliderConversionSystem.cs:14)
5. Unity.Entities.ComponentSystem.InternalUpdate () (at Library/PackageCache/com.unity.entities@0.3.0-preview.4/Unity.Entities/ComponentSystem.cs:102)
6. Unity.Entities.ComponentSystemBase.Update () (at Library/PackageCache/com.unity.entities@0.3.0-preview.4/Unity.Entities/ComponentSystemBase.cs:301)
7. Unity.Entities.ComponentSystemGroup.OnUpdate () (at Library/PackageCache/com.unity.entities@0.3.0-preview.4/Unity.Entities/ComponentSystemGroup.cs:109)
8. UnityEngine.DebugLogHandler:LogException(Exception, Object)
9. Unity.Entities.Conversion.JournalingUnityLogger:LogException(Exception, Object) (at Library/PackageCache/com.unity.entities@0.3.0-preview.4/Unity.Entities.Hybrid/GameObjectConversion/JournalingUnityLogger.cs:50)
10. UnityEngine.Debug:LogException(Exception)
11. Unity.Debug:LogException(Exception) (at Library/PackageCache/com.unity.entities@0.3.0-preview.4/Unity.Entities/Stubs/Unity/Debug.cs:19)
12. Unity.Entities.ComponentSystemGroup:OnUpdate() (at Library/PackageCache/com.unity.entities@0.3.0-preview.4/Unity.Entities/ComponentSystemGroup.cs:113)
13. Unity.Entities.ComponentSystem:InternalUpdate() (at Library/PackageCache/com.unity.entities@0.3.0-preview.4/Unity.Entities/ComponentSystem.cs:102)
14. Unity.Entities.ComponentSystemBase:Update() (at Library/PackageCache/com.unity.entities@0.3.0-preview.4/Unity.Entities/ComponentSystemBase.cs:301)
15. Unity.Entities.GameObjectConversionUtility:Convert(World) (at Library/PackageCache/com.unity.entities@0.3.0-preview.4/Unity.Entities.Hybrid/GameObjectConversion/GameObjectConversionUtility.cs:147)
16. Unity.Entities.GameObjectConversionUtility:ConvertGameObjectHierarchy(GameObject, GameObjectConversionSettings) (at Library/PackageCache/com.unity.entities@0.3.0-preview.4/Unity.Entities.Hybrid/GameObjectConversion/GameObjectConversionUtility.cs:229)

 

it's working now by changing this part:

Code (CSharp):

1.  
2. var settings = GameObjectConversionSettings.FromWorld(World.DefaultGameObjectInjectionWorld, null);
3.  
4. to
5.  
6. var settings = GameObjectConversionSettings.FromWorld(World.DefaultGameObjectInjectionWorld, new BlobAssetStore());

 

im using Entities 0.4 and this workaround dont works correctly for some android devices,(the player goes under the ground)

 

Was this ever fixed? I am getting the same issue now as well.

Edit: Nevermind did not read all of the posts in the thread.

 

Can confirm this happening in 0.14.0-preview.18 still.

this solution seems to work for me.

 

For me this results in a memory leak, using Entities 0.17.0-preview.41

 

The BlobAssetStore has to be disposed afterwards.

 

I also get a memory leak so I tried to dispose afterward and as soon as the prefab is spawned, I get lots of errors

 

Exactly, trying to fix the memory leak only results in more errors. Would love to hear how we're supposed to properly dispose a blobassetstore.

 

I have pretty much the same code as @voidraizer, only that I don't use physics with it. From what I know, Physics stores data in the BlobAssetStore so it can't be just disposed in that case.

What's holding you back from putting a "Convert to Entity" component on your prefabs?

 

Sorry, just seen that because I had the same issue and fixed it. So necro time!

I don't know your context, but on my test project, my spawner is a Monobehavior. To fix this issue, and avoid the BlobAssetStore to be garbage collected, I had to put it as a member and dispose it on destroy:

Code (CSharp):

1.  
2. public class Spawner : MonoBehaviour
3. {
4.   public GameObject unit;
5.  
6.   private EntityManager _manager;
7.   private Entity _enemyEntityPrefab;
8.   private BlobAssetStore _blobAssetStore;
9.  
10.   private void Start() {
11.     _blobAssetStore = new BlobAssetStore();
12.     _manager = World.DefaultGameObjectInjectionWorld.EntityManager;
13.     _enemyEntityPrefab = GameObjectConversionUtility.ConvertGameObjectHierarchy(
14.       unit,
15.       GameObjectConversionSettings.FromWorld(World.DefaultGameObjectInjectionWorld, _blobAssetStore)
16.     );
17.   }
18.  
19.   private void OnDestroy() {
20.     _blobAssetStore.Dispose();
21.   }
22. }
23.  

 

Easier then managing your own BlobAssetStore would be using the conversion system BlobAsset;

Code (CSharp):

1. var world = World.DefaultGameObjectInjectionWorld;
2.         var conversionSystem = world.GetExistingSystem<GameObjectConversionSystem>();
3.  
4.         var prefab = GameObjectConversionUtility.ConvertGameObjectHierarchy(unitPrefab,
5.             GameObjectConversionSettings.FromWorld(world, conversionSystem.BlobAssetStore));

If you are using IConvertGameObjectToEntity then it is even easier, since conversionSystem comes for free in the Convert method.

 

Actually in Entities 0.50 the ConvertToEntitySystem should be used like so:

Code (CSharp):

1. ConvertToEntitySystem convertToEntitySystem = World.DefaultGameObjectInjectionWorld.GetExistingSystem<ConvertToEntitySystem>();
2.         GameObjectConversionSettings settings = GameObjectConversionSettings.FromWorld(World.DefaultGameObjectInjectionWorld, convertToEntitySystem.BlobAssetStore);

(The GameObjectConversionSystem was null when I tried to use it ....)

 

This thread was created in 2019!
OP was discussing early version of entities.

Please checkout the dates before posting.

 

The reason I had posted here was because I ran into the same problem with ECS 0.50 and this thread came out in search. And I thought it would be great if the solution for the 0.50 could be found here. Sorry if I had made a mistake.

 

I still have this error and cannot fix it