Move calculation of interface data to fill_mesh_info_fv!

src/meshes/t8code_mesh.jl

@@ -1150,6 +1150,8 @@ function fill_mesh_info_fv!(mesh::T8codeMesh, interfaces, boundaries,
         for ielement in 0:(num_elements_in_tree - 1)
             element = t8_forest_get_element_in_tree(mesh.forest, itree, ielement)
 
+            level = t8_element_level(eclass_scheme, element)
+
             num_faces = t8_element_num_faces(eclass_scheme, element)
 
             # Loop over all faces of the current local element.
@@ -1213,6 +1215,24 @@ function fill_mesh_info_fv!(mesh::T8codeMesh, interfaces, boundaries,
                     boundaries.neighbor_ids[boundary_id] = current_index + 1
                     boundaries.faces[boundary_id] = iface + 1
                     boundaries.name[boundary_id] = boundary_names[iface + 1, itree + 1]
+                else # Interface or mortar.
+                    neighbor_level = t8_element_level(neighbor_scheme, neighbor_leaves[1])
+
+                    # Local interface: The second condition ensures we only visit the interface once.
+                    if level == neighbor_level && current_index <= neighbor_ielements[1]
+                        local_num_conform += 1
+                        interfaces.neighbor_ids[1, local_num_conform] = current_index +
+                                                                        1
+                        interfaces.neighbor_ids[2, local_num_conform] = neighbor_ielements[1] +
+                                                                        1
+
+                        interfaces.faces[1, local_num_conform] = iface + 1
+                        interfaces.faces[2, local_num_conform] = dual_faces[1]
+
+                        # Local mortar.
+                    elseif level < neighbor_level
+                        error("Mortars are not supported yet!")
+                    end
                 end
 
                 t8_free(dual_faces_ref[])

src/solvers/fv_t8code/containers.jl

@@ -239,42 +239,6 @@ function init_fv_interfaces(mesh::T8codeMesh, equations,
     interfaces = T8codeFVInterfaceContainer{uEltype}(u, neighbor_ids, faces,
                                                      _u, _neighbor_ids, _faces)
 
-    # I tried it to do it like for the existing T8codeMesh routines with
-    # init_interfaces!(interfaces, mesh)
-    # The problem was that I need the face id of both elements for every interface.
-    # That is not needed for DG code since it is handled with the indices there.
-
-    init_fv_interfaces!(interfaces, mesh, elements)
-
-    return interfaces
-end
-
-function init_fv_interfaces!(interfaces, mesh::T8codeMesh, elements)
-    # Note: In t8code, the routine 't8code_forest_iterate' is not implemented yet.
-
-    idx = 1
-    for element in 1:ncells(mesh)
-        (; face_connectivity, num_faces, face_midpoints, neighbor_faces) = elements[element]
-        for (face, neighbor) in enumerate(face_connectivity[1:num_faces])
-            if neighbor < element
-                continue
-            end
-
-            # face_midpoint = Trixi.get_variable_wrapped(face_midpoints, equations, face)
-            face_neighbor = neighbor_faces[face]
-            # face_midpoint_neighbor = Trixi.get_variable_wrapped(elements[neighbor].face_midpoints,
-            #                                                     equations,
-            #                                                     face_neighbor)
-            interfaces.neighbor_ids[1, idx] = element
-            interfaces.neighbor_ids[2, idx] = neighbor
-
-            interfaces.faces[1, idx] = face
-            interfaces.faces[2, idx] = face_neighbor
-
-            idx += 1
-        end
-    end
-
     return interfaces
 end