Custom struct in BlobArray

Hi,

I have an issue with struct elements in BlobArray, where they have default values in runtime. I think that I am not initializing the array correctly, but I cant find the correct approach anywhere.

Concretely, with this code, when accessing clipDataRef.Value.Motions from some job, all elements will have default values ( StartFrame = 0, EndFrame = 0, Translation = {0,0,0}).

Any advice how can I overcome this please ?

Code (CSharp):

1. [Serializable]
2. public struct Motion {
3.   public int StartFrame;
4.   public int EndFrame;
5.   public float3 Translation;
6. }
7.  
8. [Serializable]
9. public struct Clip {
10.   public bool Loop;
11.   public BlobArray<Motion> Motions;
12. }
13.  
14. public class ClipData : MonoBehaviour {
15.    public Motion[] Motions;
16.    public bool Loop;
17. }
18.  
19.  
20. class SomeConversionSystem : GameObjectConversionSystem {
21.  
22.   protected override void OnUpdate() {
23.     Entities.ForEach((ClipData clipData) =>{
24.         var builder = new BlobBuilder(Allocator.Temp);
25.         ref var root = ref builder.ConstructRoot<Clip>();
26.         root.Loop = clipData.Loop;
27.         var motions = builder.Allocate(clipData.Motions.Length, ref root.Motions);
28.  
29.         for(int i = 0; i < clipData.Motions.Length; i++) {
30.            motions[i] = clipData.Motions[i];
31.         }
32.  
33.        var clipBlob = builder.CreateBlobAssetReference<Clip>(Allocator.Persistent);
34.  
35.       builder.Dispose();
36.  
37.      var entity = GetPrimaryEntity(clipData.gameObject);
38.      DstEntityManager.AddComponentData(entity,
39.                 new SomeComponent {ClipDataRef = clipBlob});
40.      });
41.   }
42. }

 

I did not access the blobReference value correctly. I have this solved now.

Code (CSharp):

1. // Bad
2. var clips = clipDataRef.Value.Motions
3.  
4. // Good
5. ref var clips = ref clipDataRef.Value.Motions
6.  

 

It's been mentioned in another thread that they will add static analysis tools to the compiler to prevent this mistake from happening.

 

I've been looking for information about blobs, what is the advantage over a nativearray? Can it store more complex datastructures? eg. An Array of array (eg. If I had to store a rotation for each bone in one animation struct).

 

It can store arbitrary data structures, but the best way to think of it is an in-memory file, with the root blob struct being the header. It can have it's own data, but

BlobPtr<T>

,

BlobArray<T>

, and others store offsets into that file from the header.