| desc | An array or list of sub-mesh data descriptors. |
| start | Index of the first element to take from the array or list in desc. |
| count | Number of elements to take from the array or list in desc. |
| flags | (Optional) Flags controlling the function behavior, see MeshUpdateFlags. |
Sets information defining all sub-meshes in this Mesh, replacing any existing sub-meshes.
Note that SetSubMeshes, SetSubMesh, SubMeshDescriptor, and SetIndexBufferData are designed for maximum performance. These functions operate on the underlying mesh data structures involving raw index buffers, vertex buffers and mesh subset data. When you use these methods, Unity performs very little data validation, so you must ensure your data is valid.
In particular, you must ensure that the SubMeshDescriptor index ranges and SubMeshDescriptor.topology values 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 Mesh.
The SubMeshDescriptor-bounds, SubMeshDescriptor-firstVertex and SubMeshDescriptor-vertexCount values of SubMeshDescriptor are calculated automatically by SetSubMeshes, 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.
常规使用模式为：
var mesh = new Mesh();
// setup vertex buffer data mesh.vertices = ...;
// set index buffer mesh.SetIndexBufferParams(...); mesh.SetIndexBufferData(...);
// setup information about mesh subsets SubMeshDescriptor[] sm = new SubMeshDescriptor[] {...} mesh.SetSubMeshes(sm);
// update bounds of the mesh mesh.RecalculateBounds();
有关为每个子网格设置的数据的详细信息，请参阅 SubMeshDescriptor。
Additional resources: subMeshCount, GetSubMesh, SetSubMesh, SetIndexBufferParams, SetIndexBufferData, MeshUpdateFlags.