From: emv <emv@opencascade.com>
Date: Thu, 29 Nov 2018 07:20:23 +0000 (+0300)
Subject: 0030389: Data Exchange - StlAPI_Writer does not check if the face has triangulation
X-Git-Tag: V7_4_0_beta~302
X-Git-Url: http://git.dev.opencascade.org/gitweb/?p=occt.git;a=commitdiff_plain;h=44d5a096a3d978140ed01353e1ce0ccf8937fede

0030389: Data Exchange - StlAPI_Writer does not check if the face has triangulation

When merging triangulation of the faces skip those having no triangulation.
Test case for the issue.
---

diff --git a/src/StlAPI/StlAPI_Writer.cxx b/src/StlAPI/StlAPI_Writer.cxx
index 57ac659561..6433b317be 100644
--- a/src/StlAPI/StlAPI_Writer.cxx
+++ b/src/StlAPI/StlAPI_Writer.cxx
@@ -15,6 +15,8 @@
 
 #include <Bnd_Box.hxx>
 #include <BRepBndLib.hxx>
+#include <Message.hxx>
+#include <Message_Messenger.hxx>
 #include <OSD_Path.hxx>
 #include <OSD_OpenFile.hxx>
 #include <RWStl.hxx>
@@ -56,16 +58,29 @@ Standard_Boolean StlAPI_Writer::Write (const TopoDS_Shape&    theShape,
     }
   }
 
+  if (aNbTriangles == 0)
+  {
+    // No triangulation on the shape
+    return Standard_False;
+  }
+
   // create temporary triangulation
   Handle(Poly_Triangulation) aMesh = new Poly_Triangulation (aNbNodes, aNbTriangles, Standard_False);
-
+  // count faces missing triangulation
+  Standard_Integer aNbFacesNoTri = 0;
   // fill temporary triangulation
   Standard_Integer aNodeOffset = 0;
   Standard_Integer aTriangleOffet = 0;
   for (TopExp_Explorer anExpSF (theShape, TopAbs_FACE); anExpSF.More(); anExpSF.Next())
   {
+    const TopoDS_Shape& aFace = anExpSF.Current();
     TopLoc_Location aLoc;
-    Handle(Poly_Triangulation) aTriangulation = BRep_Tool::Triangulation (TopoDS::Face (anExpSF.Current()), aLoc);
+    Handle(Poly_Triangulation) aTriangulation = BRep_Tool::Triangulation (TopoDS::Face (aFace), aLoc);
+    if (aTriangulation.IsNull())
+    {
+      ++aNbFacesNoTri;
+      continue;
+    }
 
     const TColgp_Array1OfPnt& aNodes = aTriangulation->Nodes();
     const Poly_Array1OfTriangle& aTriangles = aTriangulation->Triangles();
@@ -109,7 +124,20 @@ Standard_Boolean StlAPI_Writer::Write (const TopoDS_Shape&    theShape,
   }
 
   OSD_Path aPath (theFileName);
-  return myASCIIMode
+  Standard_Boolean isDone = (myASCIIMode
        ? RWStl::WriteAscii  (aMesh, aPath)
-       : RWStl::WriteBinary (aMesh, aPath);
+       : RWStl::WriteBinary (aMesh, aPath));
+
+  if (isDone && (aNbFacesNoTri > 0))
+  {
+    // Print warning with number of faces missing triangulation
+    TCollection_AsciiString aWarningMsg =
+      TCollection_AsciiString ("Warning: ") +
+      TCollection_AsciiString (aNbFacesNoTri) +
+      TCollection_AsciiString ((aNbFacesNoTri == 1) ? " face has" : " faces have") +
+      TCollection_AsciiString (" been skipped due to null triangulation");
+    Message::DefaultMessenger()->Send (aWarningMsg, Message_Warning);
+  }
+
+  return isDone;
 }
diff --git a/tests/bugs/stlvrml/bug30389 b/tests/bugs/stlvrml/bug30389
new file mode 100644
index 0000000000..383d8953fb
--- /dev/null
+++ b/tests/bugs/stlvrml/bug30389
@@ -0,0 +1,19 @@
+puts "========"
+puts "0030389: Data Exchange - StlAPI_Writer does not check if the face has triangulation"
+puts "========"
+puts ""
+
+box b 1 1 1 
+
+# mesh only 5 faces of the box
+eval compound [lrange [explode b f] 0 4] cf
+incmesh cf 0.1
+
+# save box into stl
+writestl b $imagedir/${casename}.stl
+
+# read stl
+readstl result $imagedir/${casename}.stl -brep
+
+# check that it contains only 10 triangles
+checknbshapes result -face 10