| triangles | 定义三角形的索引的列表。 |
| submesh | The submesh to modify. |
| calculateBounds | 在设置三角形之后计算网格的包围盒。这会在默认情况下进行。 如果需要使用现有包围盒并减少设置三角形的 CPU 开销，请使用 false。 |
| baseVertex | 添加到所有三角形顶点索引的可选顶点偏移。 |
Sets the triangle list for the sub-Mesh.
A sub-Mesh is simply a separate triangle list. When the Mesh Renderer uses multiple Materials, you should
ensure that there are as many sub-Meshes as Materials.
建议在分配顶点数组之后分配三角形数组，以便避免超出边界错误。
The baseVertex argument can be used to achieve meshes that are larger than 65535 vertices while using 16 bit index buffers,
as long as each submesh fits within its own 65535 vertex area. For example, if the index buffer that is passed to SetTriangles
contains indices 10,11,12 and baseVertex is set to 100000, then effectively vertices 100010, 100011 and 100012 will be
used for rendering.
另请参阅：subMeshCount、SetIndices。