NativeArray for Meshes?

Hi!

I am super impressed with the jobsystem and burstcompiler!
you guys have done an amazing job.

as a new project to experiment with ECS i'm working on a procedurally generated terrain.
the job system takes care of generating blocks of vertex and normal data which i stream back to the mainthread to a quadtree.

right now there is a lot of complex managing involved, i schedule a couple of terrainslabs that need updating and the next frame i slice up the data i get from the job and put it back into meshes.

right now actually copying nativearray slices to the mesh takes up 80% of the time of the terrain generating process, depending how much slabs i schedule in at a time. Still its a huge performance boost.

Code (CSharp):

1.    
2. //vertices and normals are native arrays
3. //mesh_ arrays are managed / regular arrays
4. Mesh m = new Mesh();
5.                    
6. vertices.Slice(i*vertx_per_slice,vertx_per_slice).CopyTo(mesh_vertices);
7. normals.Slice(i*vertx_per_slice,vertx_per_slice).CopyTo(mesh_normals);
8.  
9. m.vertices=mesh_vertices;
10. m.normals=mesh_normals;
11.  
12. m.uv=mesh_UVs;
13. m.SetIndices(mesh_triangles,MeshTopology.Triangles,0,false);
14. m.bounds=mesh_bounds;
15.  
16. mesh_filters[scheduled_slab].mesh = m;
17.  

Is there a way to update meshes in a job ? or a better way to manipulate meshes then copying from nativeArray to the mesh ? or maybe only manipulate the vertex data and normal data ? my triangle and uv layout are the same for each terrain piece so can i keep them as native memory. Any future plans for this ?

thanx!

Rob

 

You could pin the managed/reference array, and pass the pointer to the job and do the operation straight on it instead.

 

For claritys sake, example code:

Code (csharp):

1.  
2. Vector3[] vertices = new Vector3[1024];
3. var handle = GCHandle.Alloc(vertices, GCHandleType.Pinned);
4. var ptr = (Vector3*)handle.AddrOfPinnedObject().ToPointer()
5.  

Just be aware that you need to unpin the array when the job is done, etc.

Edit: Whops... i made a new post instead of editing my old one... it's late, my bad.

 

thank you for the response, can you elaborate a little ?
I have no idea how to approach your suggestion

 

Replied with an example in a second post, should've edited the first one... my bad.

 

thanks for the example!
so i would pass the pointer to the job ?
my jobs are IJobParallelFor

Im gonna do some reseach on pinning / unpinning

 

I found this thread and i prefer to do a custom copy
https://forum.unity.com/threads/allow-setting-mesh-arrays-with-nativearrays.536736/

but I right now i'm using NativeSlice, to process a couple of meshes in one job.
Is there a way to get a pointer to a specific adress in nativeArray ?

I'm using the following code to copy, but preferable i would specify a starting point for the nativebuffer ? similar to AddressOf for the managed array

Code (CSharp):

1.      
2. int byteLength = nativeArray.Length * Marshal.SizeOf(default(T));
3. void* managedBuffer = UnsafeUtility.AddressOf(ref array[0]);
4. void* nativeBuffer = nativeArray.GetUnsafePtr();
5. Buffer.MemoryCopy(nativeBuffer, managedBuffer, byteLength, byteLength);
6.  

 

ok found it,
there is also NativeSlice.GetUnsafePtr