From e3f5ea2c483c77ce99a9a4331a03f09c74ca2926 Mon Sep 17 00:00:00 2001
From: Afeef <afeef.badri@gmail.com>
Date: Fri, 23 Jul 2021 15:37:06 +0200
Subject: [PATCH]  Fixes compound mesh failur [spns 24411] Since gmsh version
 4.3 when compund meshing is involved Gmsh produces extra discrete surfaces
 apart from the original topology  Gmsh meshing procedure needs acess to each
 of the original topology and the meshed topology.

Hence we bypass the additional DiscreteSurface mesh in case compound
meshing is involved. This bypass is needed during the GMSHPlugin_Mesher::FillSMesh()
---
 src/GMSHPlugin/GMSHPlugin_Mesher.cxx | 40 ++++++++++++++++------------
 1 file changed, 23 insertions(+), 17 deletions(-)

diff --git a/src/GMSHPlugin/GMSHPlugin_Mesher.cxx b/src/GMSHPlugin/GMSHPlugin_Mesher.cxx
index 1b7984d..c9fc7bb 100644
--- a/src/GMSHPlugin/GMSHPlugin_Mesher.cxx
+++ b/src/GMSHPlugin/GMSHPlugin_Mesher.cxx
@@ -83,22 +83,21 @@ namespace
                           std::vector< ShapeBounds > & topoEdges )
   {
     topoEdges.clear();
-#if GMSH_MAJOR_VERSION >=4
-#if GMSH_MINOR_VERSION >=3
+#if GMSH_MAJOR_VERSION >=4 && GMSH_MINOR_VERSION >=3
     for ( size_t i = 0; i < gEdge->compound.size(); ++i )
     {
       GEdge* gE = static_cast< GEdge* >( gEdge->compound[ i ]);
       topoEdges.push_back( ShapeBounds{ gE->bounds(), *((TopoDS_Edge*)gE->getNativePtr()) });
     }
 #endif
-#if GMSH_MINOR_VERSION <3
+#if GMSH_MAJOR_VERSION >=4 && GMSH_MINOR_VERSION <3
     for ( size_t i = 0; i < gEdge->_compound.size(); ++i )
     {
       GEdge* gE = static_cast< GEdge* >( gEdge->_compound[ i ]);
       topoEdges.push_back( ShapeBounds{ gE->bounds(), *((TopoDS_Edge*)gE->getNativePtr()) });
     }
 #endif
-#else
+#if GMSH_MAJOR_VERSION <4
     if ( gEdge->geomType() == GEntity::CompoundCurve )
     {
       std::vector<GEdge*> gEdges = ((GEdgeCompound*)gEdge)->getCompounds();
@@ -122,22 +121,21 @@ namespace
                           std::vector< ShapeBounds > & topoFaces )
   {
     topoFaces.clear();
-#if GMSH_MAJOR_VERSION >=4
-#if GMSH_MINOR_VERSION >=3
+#if GMSH_MAJOR_VERSION >=4 && GMSH_MINOR_VERSION >=3
     for ( size_t i = 0; i < gFace->compound.size(); ++i )
     {
       GFace* gF = static_cast< GFace* >( gFace->compound[ i ]);
       topoFaces.push_back( ShapeBounds{ gF->bounds(), *((TopoDS_Face*)gF->getNativePtr()) });
     }
 #endif
-#if GMSH_MINOR_VERSION <3
+#if GMSH_MAJOR_VERSION >=4 && GMSH_MINOR_VERSION <3
     for ( size_t i = 0; i < gFace->_compound.size(); ++i )
     {
       GFace* gF = static_cast< GFace* >( gFace->_compound[ i ]);
       topoFaces.push_back( ShapeBounds{ gF->bounds(), *((TopoDS_Face*)gF->getNativePtr()) });
     }
 #endif
-#else
+#if GMSH_MAJOR_VERSION <4
     if ( gFace->geomType() == GEntity::CompoundSurface )
     {
       std::list<GFace*> gFaces = ((GFaceCompound*)gFace)->getCompounds();
@@ -464,10 +462,8 @@ void GMSHPlugin_Mesher::FillSMesh()
     // GET topoEdge CORRESPONDING TO gEdge
     TopoDS_Edge topoEdge;
     std::vector< ShapeBounds > topoEdges;
-#if GMSH_MAJOR_VERSION >=4
-#if GMSH_MINOR_VERSION >=3
+#if GMSH_MAJOR_VERSION >=4 && GMSH_MINOR_VERSION >=3
     if(gEdge->haveParametrization())
-#endif
 #else
     if ( gEdge->geomType() != GEntity::CompoundCurve )
 #endif
@@ -558,14 +554,22 @@ void GMSHPlugin_Mesher::FillSMesh()
   {
     GFace *gFace = *it;
 
+#if GMSH_MAJOR_VERSION >=4 && GMSH_MINOR_VERSION >=3
+    // Gmsh since version 4.3 is now producing extra surface and mesh when
+    // compounds are involved. Since in Gmsh meshing procedure needs acess
+    // to each of the original topology and the meshed topology. Hence  we
+    // bypass the additional mesh in case of compounds. Note, similar cri-
+    // teria also occus in the following 'for' loop.
+    if ( _compounds.size() && gFace->geomType() == GEntity::DiscreteSurface )
+      continue;
+#endif
+
     // GET topoFace CORRESPONDING TO gFace
     TopoDS_Face topoFace;
     std::vector< ShapeBounds > topoFaces;
 
-#if GMSH_MAJOR_VERSION >=4
-#if GMSH_MINOR_VERSION >=3
+#if GMSH_MAJOR_VERSION >=4 && GMSH_MINOR_VERSION >=3
     if(gFace->haveParametrization())
-#endif
 #else
     if ( gFace->geomType() != GEntity::CompoundSurface )
 #endif
@@ -601,13 +605,15 @@ void GMSHPlugin_Mesher::FillSMesh()
   {
     GFace *gFace = *it;
 
-#if GMSH_MAJOR_VERSION >=4
-#if GMSH_MINOR_VERSION >=3
+#if GMSH_MAJOR_VERSION >=4 && GMSH_MINOR_VERSION >=3
+    if ( _compounds.size() && gFace->geomType() == GEntity::DiscreteSurface )
+      continue;
+
     bool isCompound = (!gFace->haveParametrization());
-#endif
 #else
     bool isCompound = ( gFace->geomType() == GEntity::CompoundSurface );
 #endif
+
     if ( !isCompound && gFace->getVisibility() == 0 )
       continue;  // belongs to a compound
 
-- 
2.39.2