BlobAssetReference in other BlobAsset

Are there known possibilities to create reference to blob asset inside other blob asset? For example, I have bottom tier data blobs that can be reused in some higher level structures? As far as I understand BlobPtr is method to point to data in same blob asset. Thank you in advance

 

Do you mean something like that?

Districts has sub reference Modifiers.

Code (CSharp):

1. public BlobAssetReference<BlobHashMap<FixedString64, DistrictMemory>> Districts;

Code (CSharp):

1.  
2.     public readonly struct DistrictMemory
3.     {
4.         public readonly FixedString64 Tag;
5.         public readonly FixedString128 Name;
6.         public readonly uint BuildTime;
7.         public readonly uint BuildPointCost;
8.         public readonly uint Cost;
9.  
10.         public readonly BlobAssetReference<BlobArray<FixedString64>> Modifiers;
11.  
12.         public DistrictMemory(FixedString64 tag, FixedString128 name,
13.             uint buildTime, uint buildPointCost, uint cost, BlobAssetReference<BlobArray<FixedString64>> modifiers)
14.         {
15.             Tag = tag;
16.             Name = name;
17.             BuildTime = buildTime;
18.             BuildPointCost = buildPointCost;
19.             Cost = cost;
20.             Modifiers = modifiers;
21.         }
22.     }

If this is what you are looking here are snippets how I am building it.

Code (CSharp):

1.  
2.         private BlobAssetReference<BlobHashMap<FixedString64, DistrictMemory>>         LoadDistricts(DataContainer dataContainer)
3.         {
4.             var source = new NativeHashMap<FixedString64, DistrictMemory>(4, Allocator.Temp);
5.  
6.             for (int index = 0; index < dataContainer.Jobs.Count; index++)
7.             {
8.                 var district = dataContainer.Districts[index];
9.              
10.                 source.Add(district.Tag, new DistrictMemory(
11.                     district.Tag,
12.                     district.Name,
13.                     district.BuildTime,
14.                     district.BuildPointCost,
15.                     district.Cost,
16.                     AddModifiers(district.Modifiers.ToArray())));
17.             }
18.          
19.             BlobBuilder builder = new BlobBuilder(Allocator.Temp);
20.             ref var root = ref builder.ConstructRoot<BlobHashMap<FixedString64, DistrictMemory>>();
21.             builder.ConstructHashMap(ref root, ref source);
22.             var blobMapRef = builder.CreateBlobAssetReference<BlobHashMap<FixedString64, DistrictMemory>>(Allocator.Persistent);
23.  
24.             return blobMapRef;
25.         }

Code (CSharp):

1.  
2.         private BlobAssetReference<BlobArray<FixedString64>> AddModifiers(params string[] tags)
3.         {
4.             using (var builder = new BlobBuilder(Allocator.Temp)) {
5.                 ref BlobArray<FixedString64> root = ref builder.ConstructRoot<BlobArray<FixedString64>>();
6.  
7.                 var nodearray = builder.Allocate(ref root, tags.Length);
8.  
9.                 for (var index = 0; index < tags.Length; index++)
10.                 {
11.                     var tag = tags[index];
12.                     nodearray[index] = tag;
13.                 }
14.  
15.                 return builder.CreateBlobAssetReference<BlobArray<FixedString64>>(Allocator.Persistent);
16.             }
17.         }

 

Thank you for quick response. Yes, your case is similar to mine. But I made tiny example that failed for me:

public struct TestStruct

{

    public BlobAssetReference<float> blobAssetFloat;

}

....

var bb = new BlobBuilder(Allocator.Temp);

ref var ts = ref bb.ConstructRoot<TestStruct>();

And I have a compile error:

error ConstructBlobWithRefTypeViolation: You may not build a type TestStruct with Construct as TestStruct.blobAssetFloat.m_data.m_Ptr is a reference or pointer.  Only non-reference types are allowed in Blobs.

I use Entities 0.17.0-preview.42 package with Unity 2021.2.0b16. Yes I know about "2020 only supported version, but everything went smooth for now. What version are you using?

 

Found solution: Entities 0.17 changelog. Seems Entities package issue

 

Sorry about that I forgot that I had to change the same thing to get it working.

And I am using 2021.2 too. UI toolkit is so much better on the newer version.

 

Thank you very mush for responses. Joachim, indexing into other blob array is actually viable solution, I didn't think that way, thank you. Making self contained blob asset is always an option, but I try study every aspect of Unity ECS, and wanted to solve my tasks the "proper and logical way" first. Besides such interblob referenses are logical requirement for complex data structures.