0027959: BRepMesh_Delaun produces mesh with gaps on internal edges

Check both sides of internal link for adjusted triangle and process left and right polygons separately
Small correction of test case for issue CR27959

diff --git a/src/BRepMesh/BRepMesh_Delaun.cxx b/src/BRepMesh/BRepMesh_Delaun.cxx
index edd8a5c53914c68718297a5c8211b63cb502c821..a7e8b4896ffccd32c80d7fe7432e2ac005f81c85 100644 (file)
--- a/src/BRepMesh/BRepMesh_Delaun.cxx
+++ b/src/BRepMesh/BRepMesh_Delaun.cxx
@@ -508,25 +508,56 @@ void BRepMesh_Delaun::createTrianglesOnNewVertices(
       createTriangles( aVertexIdx, aLoopEdges );
     }
   }
-  // Check that internal edges are not crossed by triangles
+
+  insertInternalEdges();
+
+  // Adjustment of meshes to boundary edges
+  frontierAdjust();
+}
+
+//=======================================================================
+//function : insertInternalEdges
+//purpose  : 
+//=======================================================================
+void BRepMesh_Delaun::insertInternalEdges()
+{
   BRepMesh::HMapOfInteger anInternalEdges = InternalEdges();
 
   // Destruction of triancles intersecting internal edges 
   // and their replacement by makeshift triangles
+  Standard_Integer e[3];
+  Standard_Boolean o[3];
   BRepMesh::MapOfInteger::Iterator anInernalEdgesIt( *anInternalEdges );
   for ( ; anInernalEdgesIt.More(); anInernalEdgesIt.Next() )
   {
-    Standard_Integer aNbC;
-    aNbC = myMeshData->ElementsConnectedTo( anInernalEdgesIt.Key() ).Extent();
-    if ( aNbC == 0 )
+    const Standard_Integer aLinkIndex = anInernalEdgesIt.Key();
+    const BRepMesh_PairOfIndex& aPair = myMeshData->ElementsConnectedTo(aLinkIndex);
+
+    // Check both sides of link for adjusted triangle.
+    Standard_Boolean isGo[2] = { Standard_True, Standard_True };
+    for (Standard_Integer aTriangleIt = 1; aTriangleIt <= aPair.Extent(); ++aTriangleIt)
     {
-      meshLeftPolygonOf( anInernalEdgesIt.Key(), Standard_True  ); 
-      meshLeftPolygonOf( anInernalEdgesIt.Key(), Standard_False ); 
+      GetTriangle(aPair.Index(aTriangleIt)).Edges(e, o);
+      for (Standard_Integer i = 0; i < 3; ++i)
+      {
+        if (e[i] == aLinkIndex)
+        {
+          isGo[o[i] ? 0 : 1] = Standard_False;
+          break;
+        }
+      }
     }
-  }
 
-  // Adjustment of meshes to boundary edges
-  frontierAdjust();
+    if (isGo[0])
+    {
+      meshLeftPolygonOf(aLinkIndex, Standard_True);
+    }
+
+    if (isGo[1])
+    {
+      meshLeftPolygonOf(aLinkIndex, Standard_False);
+    }
+  }
 }
 
 //=======================================================================

diff --git a/src/BRepMesh/BRepMesh_Delaun.hxx b/src/BRepMesh/BRepMesh_Delaun.hxx
index 37db10c277bcf95706a67ef4df3db4477e313b49..e8fcba595e5a975fa2c4b92627460fc861fc1691 100755 (executable)
--- a/src/BRepMesh/BRepMesh_Delaun.hxx
+++ b/src/BRepMesh/BRepMesh_Delaun.hxx
@@ -320,6 +320,9 @@ private:
                           const Standard_Integer             theStartIndex,
                           const Standard_Integer             theEndIndex) const;
 
+  //! Performs insertion of internal edges into mesh.
+  void insertInternalEdges();
+
 private:
 
   Handle(BRepMesh_DataStructureOfDelaun) myMeshData;

diff --git a/tests/bugs/mesh/bug27959 b/tests/bugs/mesh/bug27959
new file mode 100644 (file)
index 0000000..cdf6fb1
--- /dev/null
+++ b/tests/bugs/mesh/bug27959
@@ -0,0 +1,21 @@
+puts "=========="
+puts "OCC27959"
+puts "=========="
+puts ""
+#######################################################################
+# BRepMesh_Delaun produces mesh with gaps on internal edges
+#######################################################################
+# test for #27959: check that resulting mesh does not contain gaps.
+
+restore [locate_data_file bug27959_ms.brep] result
+
+tclean result
+checkview -display result -3d -path ${imagedir}/${test_image}.png
+
+set log [tricheck result]
+if { [llength $log] != 0 } {
+  puts "Error : Mesh contains gaps"
+} else {
+  puts "OK : Mesh produced without gaps"
+}
+