private void ConvertTerrain2Mesh(Terrain terrain)
{
var meshes = MeshUtil.ConvertTerrain2Mesh(terrain, _indexFormat, _splitCount, _lod);
var rootGo = new GameObject($"{terrain.name}_{_lod}");
rootGo.CopyTransform(terrain.gameObject);
var tileGridNum = (int)Mathf.Pow(2, _splitCount);
var tileSize = terrain.terrainData.size.x / tileGridNum;
for (int i = 0; i < meshes.Count; i++)
{
var mesh = meshes[i];
// 从下往上，再从左往右
var widthIndex = i / tileGridNum;
var heightIndex = i % tileGridNum;
var go = new GameObject($"{terrain.name}_{_lod}_mesh_{widthIndex}_{heightIndex}");
go.transform.SetParent(rootGo.transform);
go.transform.localPosition = new Vector3(widthIndex * tileSize, 0, heightIndex * tileSize);
var filer = go.AddComponent <MeshFilter>();
filer.mesh = mesh;
var renderer = go.AddComponent <MeshRenderer>();
// renderer.sharedMaterial = AssetDatabase.GetBuiltinExtraResource<Material>("Default-Terrain-Standard.mat");
renderer.sharedMaterial = AssetDatabase.GetBuiltinExtraResource <Material>("Default-Material.mat");
InitMeshRenderer(terrain, renderer, tileGridNum, widthIndex, heightIndex);
}
}