Question Runtime mesh changes resulting in nothing rendered?

I am trying to update the mesh on a large number of entities at runtime, based on data in the entity's other components (for some dynamic terrain). However, no matter what I try, I cannot seem to get the EntitiesGraphicsSystem to actually render the meshes, resulting in a completely empty scene.

Distilled down, my mesh building code looks like this:

Spoiler

Code (CSharp):

1.  
2. private void UpdateDirtyMeshes()
3. {
4.     using var dirtyEntities = tileWithDirtyGroundQuery.ToEntityArray(Allocator.Temp);
5.  
6.     if (dirtyEntities.Length == 0)
7.     {
8.         // skip updating if nothing needs it
9.         return;
10.     }
11.  
12.     // make some mesh data arrays for the job to build the meshes
13.     var meshDataArrays = new UnsafeList<Mesh.MeshDataArray>(dirtyEntities.Length, Allocator.TempJob);
14.     for (var i = 0; i < dirtyEntities.Length; i++)
15.     {
16.         meshDataArrays.AddNoResize(Mesh.AllocateWritableMeshData(1));
17.     }
18.  
19.     // pass the data arrays to the job to populate
20.     var meshBuildJob = new MeshBuildJob
21.     {
22.         // other stuff...
23.         MeshDataArrays = meshDataArrays
24.     };
25.     var meshBuildJobHandle = meshBuildJob.Schedule(dirtyEntities.Length, 1, Dependency);
26.     meshBuildJobHandle.Complete();
27.  
28.     for (var i = 0; i < dirtyEntities.Length; i++)
29.     {
30.         // get the "ground" entity which holds the mesh
31.         var ground = EntityManager.GetComponentData<MapTileGroundEntity>(dirtyEntities[i]).Value;
32.         var mmi = EntityManager.GetComponentData<MaterialMeshInfo>(ground);
33.  
34.         // in this case, I'm dropping the old mesh and making a new one
35.         // I have also tried to simply update the existing mesh, but that doesn't work either
36.         if (mmi.Mesh > 0)
37.         {
38.             // unregister the old mesh
39.             entitiesGraphicsSystem.UnregisterMesh(new BatchMeshID { value = (uint)mmi.Mesh });
40.         }
41.  
42.         // build and register a new mesh
43.         var mesh = new Mesh() { name = "GroundMesh_" + ground.Index };
44.         Mesh.ApplyAndDisposeWritableMeshData(meshDataArrays[i], mesh);
45.         mesh.RecalculateNormals();
46.         mesh.RecalculateBounds();
47.         mesh.RecalculateTangents();
48.  
49.         // for debugging, update a component that shows us the mesh in the inspector
50.         EntityManager.SetComponentData(ground, new MapTileGroundMesh { Value = mesh });
51.  
52.         // update the bounds on the component
53.         var bounds = mesh.bounds;
54.         EntityManager.SetComponentData(entity, new RenderBounds { Value = new() { Center = bounds.center, Extents = bounds.extents } });
55.  
56.         // register the new mesh with the EGS and update the mesh ID
57.         var meshId = entitiesGraphicsSystem.RegisterMesh(mesh);
58.         EntityManager.SetComponentData(ground, new MaterialMeshInfo { Mesh = (int)meshId.value, Material = mmi.Material, Submesh = mmi.Submesh });
59.     }
60.  
61.     // additional work on other parts of the entity, cleanup/disposing things, etc.
62.     // ...
63. }
64.  

For reference, this entity is built as a prototype and cloned earlier by EntityManager.Instantiate then adding a Parent component to it once built.

The prototype is built like so:

Spoiler

Code (CSharp):

1.  
2. EntityManager entityManager = // ...
3. Material material = // This is currently using the standard URP "Lit" material
4.  
5. entityManager.AddComponentData(entity, new LocalTransform { Scale = 1 });
6. entityManager.AddComponent<WorldTransform>(entity);
7. entityManager.AddComponent<LocalToWorld>(entity);
8. RenderMeshUtility.AddComponents
9.     entityManager,
10.     entity,
11.     new RenderMeshDescription(ShadowCastingMode.ShadowsOnly),
12.     new RenderMeshArray(new Material[] { material }, new Mesh[0]),
13.     new MaterialMeshInfo { Mesh = 0, Material = -1 });
14. // plus my custom components, too
15.  

From my understanding by reading through the scripts, MaterialMeshInfo's Mesh/Material properties can be positive for a batched mesh's ID, or negative to index the shared RenderMeshArray. Since they all share a material, it can be in the RenderMeshArray, but I'll be updating the mesh at runtime and each will have a different mesh (plus don't want structural changes for doing so), so that's just going to be zero for now.

After this method executes, I can see all my tiles in the hierarchy window correctly:


(The appropriate WorldRenderBounds is also correct, per the tile's transform)

I can also inspect the resulting mesh to find it looks correct when viewed in the inspector's little viewport. So, all that appears to have worked:

(It's a very simple mesh for now, but will get more complicated once this is working)

Yet, despite that, nothing is rendered in the scene: it is in fact completely empty. I've been at this for quite some time and just cannot figure out what the missing piece is; what am I doing wrong?

Spoiler: Unity Info

Unity Editor 2022.2.7f1
Universal Rendering Pipeline 14.0.6
Unity.Entities 1.0.0-pre.47
Unity.Entities.Rendering 1.0.0-pre.44

 

Looks very similar to what I do and it works. Two ideas: (1) not casting BatchMeshID. (2) check if LocalTransform is set correctly (i.e. that it does not have scale „0“ or invalid rotation)?

Edit: it think your bug is in how you setup MaterialMeshInfo. I set it up using BatchMaterialID and BatchMeshID.

Code (CSharp):

1. BatchMaterialID materialID = hybridRenderer.RegisterMaterial(yourMaterial)
2. BatchMeshID meshID = hybridRenderer.RegisterMesh(yourMesh)
3. entityManager.SetComponentData(prototype, new MaterialMeshInfo(materialID, meshID));
4. or
5. _entityManager.SetComponentData(prototype, new MaterialMeshInfo {MeshID = meshID, MaterialID = materialID });

Code (CSharp):

1. var meshID = hybridRenderer.RegisterMesh(receivingMeshArray[0]);
2. //I manually add components instead of using RenderMeshUtility function
3. _entityManager.AddComponent(prototype, renderTypeset);
4. _entityManager.AddComponent(prototype, areaOrBoxColorTypeset);
5. _entityManager.AddComponentData(prototype, new AreaColorMeshState { meshID = meshID });//ICleanupComponentData used to track destruction to enable cleanup (unregister mesh, destroy mesh)
6. _entityManager.SetSharedComponentManaged(prototype, renderMeshDescription.FilterSettings);
7. _entityManager.SetComponentData(prototype, new MaterialMeshInfo(materialID, meshID));
8. _entityManager.SetComponentData(prototype, new RenderBounds { Value = receivingMeshArray[0].bounds.ToAABB() });
9. _entityManager.SetComponentData(prototype, LocalTransform.Identity);//ensures that scale is not zero, rotation is quaternion.identity
10.