From 14975f5329eaf3d787e1bbc27371fe6dc44bae8a Mon Sep 17 00:00:00 2001
From: Peter Munch <peterrmuench@gmail.com>
Date: Mon, 25 Oct 2021 06:50:59 +0200
Subject: [PATCH] Introduce TriaAccessor::combined_face_orientation()

---
 include/deal.II/grid/tria_accessor.h          | 19 ++++++++++++
 .../deal.II/grid/tria_accessor.templates.h    | 30 +++++++++++++++++++
 source/numerics/data_out_faces.cc             |  6 +---
 3 files changed, 50 insertions(+), 5 deletions(-)

diff --git a/include/deal.II/grid/tria_accessor.h b/include/deal.II/grid/tria_accessor.h
index 2dbd027010..8e5641cbbc 100644
--- a/include/deal.II/grid/tria_accessor.h
+++ b/include/deal.II/grid/tria_accessor.h
@@ -899,6 +899,13 @@ public:
    * @{
    */
 
+  /**
+   * Return an integer representation that uniquely encodes the orientation,
+   * flip, and rotation of a @p face.
+   */
+  unsigned char
+  combined_face_orientation(const unsigned int face) const;
+
   /**
    * Return whether the face with index @p face has its normal pointing in the
    * standard direction (@p true) or whether it is the opposite (@p false).
@@ -2104,6 +2111,12 @@ public:
    * @{
    */
 
+  /**
+   * @brief Always return 0
+   */
+  static unsigned char
+  combined_face_orientation(const unsigned int face);
+
   /**
    * @brief Always return false
    */
@@ -2570,6 +2583,12 @@ public:
    * @{
    */
 
+  /**
+   * @brief Always return 0
+   */
+  static unsigned char
+  combined_face_orientation(const unsigned int face);
+
   /**
    * @brief Always return false
    */
diff --git a/include/deal.II/grid/tria_accessor.templates.h b/include/deal.II/grid/tria_accessor.templates.h
index b656d517c5..f19b16feed 100644
--- a/include/deal.II/grid/tria_accessor.templates.h
+++ b/include/deal.II/grid/tria_accessor.templates.h
@@ -1188,6 +1188,17 @@ TriaAccessor<structdim, dim, spacedim>::quad_index(const unsigned int i) const
 
 
 
+template <int structdim, int dim, int spacedim>
+inline unsigned char
+TriaAccessor<structdim, dim, spacedim>::combined_face_orientation(
+  const unsigned int face) const
+{
+  return this->face_orientation(face) + 4 * this->face_flip(face) +
+         2 * this->face_rotation(face);
+}
+
+
+
 template <int structdim, int dim, int spacedim>
 inline bool
 TriaAccessor<structdim, dim, spacedim>::face_orientation(
@@ -2527,6 +2538,16 @@ TriaAccessor<0, dim, spacedim>::measure() const
 
 
 
+template <int dim, int spacedim>
+inline unsigned char
+TriaAccessor<0, dim, spacedim>::combined_face_orientation(
+  const unsigned int /*face*/)
+{
+  return 0;
+}
+
+
+
 template <int dim, int spacedim>
 inline bool
 TriaAccessor<0, dim, spacedim>::face_orientation(const unsigned int /*face*/)
@@ -2959,6 +2980,15 @@ TriaAccessor<0, 1, spacedim>::manifold_id() const
 }
 
 
+template <int spacedim>
+inline unsigned char
+TriaAccessor<0, 1, spacedim>::combined_face_orientation(
+  const unsigned int /*face*/)
+{
+  return 0;
+}
+
+
 template <int spacedim>
 inline bool
 TriaAccessor<0, 1, spacedim>::face_orientation(const unsigned int /*face*/)
diff --git a/source/numerics/data_out_faces.cc b/source/numerics/data_out_faces.cc
index aaca186ddc..bcc04bff84 100644
--- a/source/numerics/data_out_faces.cc
+++ b/source/numerics/data_out_faces.cc
@@ -117,11 +117,7 @@ DataOutFaces<dim, spacedim>::build_one_patch(
       const Point<dim> vertex_reference_coordinates =
         cell->reference_cell().template vertex<dim>(
           cell->reference_cell().face_to_cell_vertices(
-            face_number,
-            vertex,
-            cell->face_orientation(face_number) +
-              4 * cell->face_flip(face_number) +
-              2 * cell->face_rotation(face_number)));
+            face_number, vertex, cell->combined_face_orientation(face_number)));
 
       const Point<dim> vertex_real_coordinates =
         data.mapping_collection[0].transform_unit_to_real_cell(
-- 
2.39.5