Save/Correct way to handle BlobAssetReference

Unity Engine
,
1

Wondering if someone could please help me out. Basically I want to create BlobAssetReference from different GO using IConvertGameObjectToEntity and then add them all to a single entity in a GameObjectConversionSystem.

How do i create a BlobAssetReference safely outside using{}, access it in a GameObjectConversionSystem and dispose.

public class GameObj_A_Authoring : MonoBehaviour, IConvertGameObjectToEntity
{
    public void Convert(Entity entity, EntityManager dstManager, GameObjectConversionSystem conversionSystem)
    {
        BlobAssetReference<DataA>  basDataA = BuildBlobA();
    }

}

public class GameObj_B_Authoring : MonoBehaviour, IConvertGameObjectToEntity
{
    public void Convert(Entity entity, EntityManager dstManager, GameObjectConversionSystem conversionSystem)
    {
        BlobAssetReference<DataB>  basDataB = BuildBlobB();
    }

}

public class MyConversionSystem : GameObjectConversionSystem
{
  //.. Safely create and add this to an entity
  var comp = new AllBlobsComponent
  {
      // add BlobAssetReference<DataA>
      // add BlobAssetReference<DataB>
  };
 
}

Can any one please share a simple example to safely do this. Thank you heaps in advance

2

I don’t know how to combine existing BlobAssets, but you might be able to restructure your code to take a BlobBuilder.

struct ComponentA { public int x; }
struct ComponentB { public BlobArray<int> y; }
struct AllBlobs { public ComponentA a; public ComponentB b; }

class ComponentA_Authoring {
    public void SetBlobData(ref ComponentA obj, ref BlobBuilder bb) {
        obj.x = 15; } }

class ComponentB_Authoring {
    public void SetBlobData(ref ComponentB obj, ref BlobBuilder bb) {
        BlobBuilderArray<int> arr = bb.Allocate(ref obj.y, 3);
        arr[0] = 10;
        arr[1] = -60;
        arr[2] = 88; } }

class MyConversionSystem {
    public BlobAssetReference<AllBlobs> Convert() {
        BlobBuilder bb = new BlobBuilder(Allocator.Temp);
        ref AllBlobs root = ref bb.ConstructRoot<AllBlobs>();
        myComponentA.SetBlobData(ref root.a, ref bb);
        myComponentB.SetBlobData(ref root.b, ref bb);
        return bb.CreateBlobAssetReference<AllBlobs>(Allocator.Persistent); } }

For a bigger example: https://gitlab.com/burningmime/easybuilding/-/blob/master/Packages/building/src/Building.cs#L633

1 Like
3

Thank you let me try this out

4

Look at physics conversion, it’s pretty much what it does.

5

For the life of me i cant find it, Iv only downloaded the physics package for the first time today so pretty lost, I found Library/PackageCache/com.unity.physics@0.4.0-preview.5/Unity.Physics.Hybrid/Conversion but cant find the example you are referring too.

6

Oh sorry, I kind of miss read your original post.

I thought you were trying to apply the same blob asset reference to multiple entities, but you want to create references on multiple entities then group them after on a single entity.

Could you just make your final conversion system run after the conversion is done and filter on the destination world?

7

“Could you just make your final conversion system run after the conversion is done and filter on the destination world”

not sure follow , so I just create a BlobAssetReference in each conversion, store it in the destination world on the primary entity and then in the conversion system create a new entity and add each BlobAssetReference so that I have a single entity with a component container a BlobAssetReference to each blob

8

Seems like you follow fine!

9

Fantastic , thank you