| index | Sub-mesh index. See subMeshCount. Out of range indices throw an exception. |
| desc | Sub-mesh data. |
| flags | Flags controlling the function behavior, see MeshUpdateFlags. |
Sets the information about a sub-mesh of the Mesh.
Note that SetSubMesh, SubMeshDescriptor, and SetIndexBufferData are designed for advanced users aiming for maximum performance, because they operate on the underlying mesh data structures that primarily work on raw index buffers, vertex buffers and mesh subset data. Using these methods, Unity performs very little data validation, so you must ensure your data is valid.
In particular, you must ensure that the SubMesh index range and topology are set to correct values. SubMesh indices, both indexStart and indexCount, must not overlap with any other SubMesh indices.
For information about the difference between the simpler and more advanced methods of assigning data to a Mesh from script, see the notes on the Mesh page.
The SubMeshDescriptor-bounds, SubMeshDescriptor-firstVertex and SubMeshDescriptor-vertexCount values of SubMeshDescriptor
are calculated automatically by SetSubMesh, unless MeshUpdateFlags.DontRecalculateBounds flag is passed. Note that this only applies to the bounds of the SubMesh. You must call Mesh.RecalculateBounds to recalculate the bounds of the Mesh itself.
General usage pattern is:
var mesh = new Mesh();
// setup vertex buffer data mesh.vertices = ...;
// set index buffer mesh.SetIndexBufferParams(...); mesh.SetIndexBufferData(...);
// setup information about mesh subsets mesh.subMeshCount = ...; mesh.SetSubMesh(index, ...);
// update bounds of the mesh mesh.RecalculateBounds();
For details on what data to set up for each sub-mesh, see SubMeshDescriptor.
Additional resources: subMeshCount, GetSubMesh, SetIndexBufferParams, SetIndexBufferData, MeshUpdateFlags.