Bug ApplyAndDisposeWritableMeshData applies same data to all meshes.

Code (CSharp):

1. Mesh.ApplyAndDisposeWritableMeshData(
2.    data: tangentJob.outputBranches,
3.    meshes: meshes
4. );

Calling this version of the function.

Code (CSharp):

1. public static void ApplyAndDisposeWritableMeshData(MeshDataArray data, Mesh[] meshes, MeshUpdateFlags flags = MeshUpdateFlags.Default);

I verified the data in the outputBranches MeshDataArray is different by outputing the vertexCount of outputBranches and the vertexCount of the meshes Mesh array. They do not match.

The erroneous result is the Mesh instances in the meshes array have the same vertex and index count, which matches the first Mesh instance in the outputBranches MeshDataArray.

It is also not recalculating bounds.

Pretty sure there is a bug in ApplyAndDisposeWritableMeshData.

Unity version 2022.1.23f1
Jobs: 0.51.0-preview.32

More complete code for further analysis:

Code (CSharp):

1. var tangentJob = new BuildMeshTangentsJob()
2.             {
3.                 inputBranches = meshBuilder.GetReadOnlyMeshDataArray(),
4.                 outputBranches = AllocateWritableMeshData(meshBuilder.branchMeshes.Count)
5.             };
6.          
7.             JobHandle handle = tangentJob.Schedule(meshBuilder.branchMeshes.Count, 1);
8.  
9.             Mesh[] meshes = new Mesh[meshBuilder.branchMeshes.Count];
10.             Array.Fill(meshes, new Mesh());
11.  
12.             handle.Complete();
13.  
14.             for (int bN = 0; bN < 12; bN++)
15.             {
16.                 Debug.Log(
17.                     $"i:{bN} of {tangentJob.outputBranches.Length} - Output: {tangentJob.outputBranches[bN].vertexCount} , indexes: , " +
18.                     $"Input: {meshBuilder.branchMeshes[bN].vertexCount}, indexes: "
19.                 );
20.             }
21.  
22.             ApplyAndDisposeWritableMeshData(
23.                 data: tangentJob.outputBranches,
24.                 meshes: meshes
25.             );
26.  
27.             for (int bN = 0; bN < meshes.Length; bN++)
28.             {
29.                 meshes[bN].RecalculateBounds();
30.                 if (bN < 12)
31.                 {
32.                     Debug.Log(
33.                         $"i:{bN} of {tangentJob.outputBranches.Length} - Output -- vertexes: {meshes[bN].vertexCount}, indexes: {meshes[bN].GetIndexCount(0)}, " +
34.                         $"Input: {meshBuilder.branchMeshes[bN].vertexCount}, indexes: {meshBuilder.branchMeshes[bN].GetIndexCount(0)}\n" +
35.                         $"{string.Join(", ", meshes[bN].vertices[0..5])}\n" +
36.                         $"{string.Join(", ", meshes[bN].triangles[0..24])}"
37.                     );
38.                 }
39.             }
40.  

 

Array Fill was the wrong call. It was filling the entire array with a reference to the same mesh.

Code (CSharp):

1. Array.Fill(meshes, new Mesh());

Would be nice if ApplyAndDisposeWritableMeshData could handle null values.

 

You could create your own MeshDataArray and add MeshData excluding nulls, then apply and dispose