...

mcc/mcc_generics.h

@@ -527,6 +527,10 @@ struct mcc_pzone_interface_t {
         return std::forward<SelfT>(self).timeFromPZone(std::move(coords), res_time);
     }
 
+    //
+    // NOTE: the method must return:
+    //     point = mcc_celestial_point_c{.pair_kind = MccCoordPairKind::COORDS_KIND_GENERIC, .X = NaN, .Y = NaN}
+    //             if there is no intersection with the zone for given coordinates!
     template <std::derived_from<mcc_pzone_interface_t> SelfT, typename InputT>
     RetT intersectPZone(this SelfT&& self, InputT coords, mcc_celestial_point_c auto* point)
         requires(mcc_eqt_hrz_coord_c<InputT> || mcc_celestial_point_c<InputT>) &&