public Vector3f getTileCell(Vector3f location) {
        Vector3f tileLoc = location.divide(this.getWorldScale().mult(this.quadSize));
        return tileLoc;
    }
Centered at 0,0.
Get the tile index location in integer form:
@param location world coordinate
jme3-terrain/src/main/java/com/jme3/terrain/geomipmap/TerrainGrid.java