ENH: add support for reading vtk with hasNativeCoordinates

Co-authored-by: volodia99 <gaylor.wafflard@univ-grenoble-alpes.fr>

pytools/vtk_io.py

@@ -59,6 +59,7 @@ def _load_header(self, fh, geometry=None):
         self._dataset_type = line.split()[1]
 
         self.geometry = geometry
+        self._has_native_coordinates = False
 
         ref_position = fh.tell()
         line = fh.readline().decode("utf-8")  # DIMENSIONS NX NY NZ or FIELD
@@ -88,6 +89,8 @@ def _load_header(self, fh, geometry=None):
                     self.t = np.fromfile(fh, dt, 1)
                 elif d.startswith("PERIODICITY"):
                     self.periodicity = np.fromfile(fh, dtype=dint, count=3).astype(bool)
+                elif d.startswith("HAS_NATIVE_COORDINATES"):
+                    self._has_native_coordinates = np.fromfile(fh, dtype=dint, count=1).astype(bool)
                 else:
                     warnings.warn("Found unknown field %s" % d)
                 fh.readline()  # skip extra linefeed (empty line)
@@ -338,6 +341,29 @@ def _load_hydro(self, fh):
 
             fh.readline()  # extra line feed
 
+        if self._has_native_coordinates:
+            if self.geometry == "spherical":
+                native2attr = {
+                    "X1L_NATIVE_COORDS": "rl",
+                    "X1C_NATIVE_COORDS": "r",
+                    "X2L_NATIVE_COORDS": "thetal",
+                    "X2C_NATIVE_COORDS": "theta",
+                    "X3L_NATIVE_COORDS": "phil",
+                    "X3C_NATIVE_COORDS": "phi",
+                }
+            elif self.geometry in ("cartesian", "cylindrical", "polar"):
+                native2attr = {
+                    "X1L_NATIVE_COORDS": "xl",
+                    "X1C_NATIVE_COORDS": "x",
+                    "X2L_NATIVE_COORDS": "yl",
+                    "X2C_NATIVE_COORDS": "y",
+                    "X3L_NATIVE_COORDS": "zl",
+                    "X3C_NATIVE_COORDS": "z",
+                }
+
+            for native_field, attr in native2attr.items():
+                setattr(self, attr, self.data[native_field])
+
     def _load_particles(self, fh):
         raise NotImplementedError("Particles vtk are not supported yet !")