Is managed data still needed?

@keenanwoodall Since latest versions of Unity support Mesh.SetVertices, Mesh.SetNormals, etc with native arrays I was wondering if we still need to do this step?

From MeshData.cs:

// Copy the native data into the managed data for efficient transfer into the actual mesh.
DataUtils.CopyNativeDataToManagedData(dynamicManaged, DynamicNative, dataFlags);

I have tried bypassing it and doing this instead and it works fine, I think it might be more efficient since we can skip the managed overhead entirely?

if ((dataFlags & DataFlags.Vertices) != 0)
				DynamicMesh.SetVertices(DynamicNative.VertexBuffer);
			if ((dataFlags & DataFlags.Normals) != 0)
				DynamicMesh.SetNormals(DynamicNative.NormalBuffer);
			if ((dataFlags & DataFlags.Tangents) != 0)
				DynamicMesh.SetTangents(DynamicNative.TangentBuffer);
			if ((dataFlags & DataFlags.UVs) != 0)
				DynamicMesh.SetUVs(0,DynamicNative.UVBuffer);
			if ((dataFlags & DataFlags.Colors) != 0)
				DynamicMesh.SetColors(DynamicNative.ColorBuffer);
...etc...

If not then there is separate optimization I’d like to propose/implement that will be faster than MemCpy (see bottom of this page if curious: https://jacksondunstan.com/articles/4713 where CopyFromFast and CopyToFast is discussed)

Just want to get some thoughts on this in case I’m missing something, otherwise I’m thinking about stripping out the managed data stuff and submitting a pull request!

[keenanwoodall]

Preprocessor stuff has been added so it uses managed data before 2019.3 I made a test fbx with submeshes to see how it breaks and realized it wasn’t going to break because no deformer (that I’ve made) marks the triangles as changed in the data flags so it never gets copied.

I removed the data flags check so it always copies the triangles and the result was the first material being applied to the entire mesh since it was treated as one submesh. Was that how it broke for you, or did it do something else? Did you have a custom deformer that was modifying the triangles? I’m curious what caused the break.

I tried changing the code that sets the indices to this

if ((dataFlags & DataFlags.Triangles) != 0)
{
	for (int i = 0; i < to.subMeshCount; i++)
	{
		var submesh = to.GetSubMesh(i);
		to.SetIndices
		(
			indices: 		from.IndexBuffer,
			indicesStart: 		submesh.indexStart, 
			indicesLength:		submesh.indexCount, 
			topology: 		submesh.topology, 
			submesh: 		i, 
			calculateBounds: 	false, 
			baseVertex: 		submesh.baseVertex
		);
	}
}

it’s on develop and it seems to work as well 👍

[keenanwoodall]

Yea when I originally wrote this you couldn’t copy directly to the mesh from native collections. I’m glad the mesh API finally caught up! I just pushed the changes to develop. I think it should be stable, but like with other stuff I’ll sit on it a bit longer before merging.