0021130: EDF 1746 SMESH: Issue with export in STL format

1) write not triangular faces as many triangles
   2) write triangles for missing faces of free facets of volumes

src/DriverSTL/DriverSTL_W_SMDS_Mesh.cxx

@@ -24,22 +24,25 @@
 
 #include "DriverSTL_W_SMDS_Mesh.h"
 
+#include "SMDS_FaceOfNodes.hxx"
+#include "SMDS_IteratorOnIterators.hxx"
 #include "SMDS_Mesh.hxx"
 #include "SMDS_MeshElement.hxx"
 #include "SMDS_MeshNode.hxx"
-#include <gp_XYZ.hxx>
+#include "SMDS_SetIterator.hxx"
-#include <OSD_Path.hxx>
+#include "SMDS_VolumeTool.hxx"
+#include "SMESH_TypeDefs.hxx"
+
 #include <OSD_File.hxx>
-#include <OSD_FromWhere.hxx>
+//#include <OSD_FromWhere.hxx>
+#include <OSD_Path.hxx>
 #include <OSD_Protection.hxx>
-#include <OSD_SingleProtection.hxx>
+//#include <OSD_SingleProtection.hxx>
 #include <TCollection_AsciiString.hxx>
-#include <TColgp_Array1OfXYZ.hxx>
+#include <gp_XYZ.hxx>
 
 #include "utilities.h"
 
-//using namespace std;
-
 // definition des constantes 
 static const int LABEL_SIZE = 80;
 
@@ -61,6 +64,7 @@ Driver_Mesh::Status DriverSTL_W_SMDS_Mesh::Perform()
     fprintf(stderr, ">> ERROR : Mesh is null \n");
     return DRS_FAIL;
   }
+  findVolumeTriangles();
   if ( myIsAscii )
     aResult = writeAscii();
   else
@@ -68,6 +72,68 @@ Driver_Mesh::Status DriverSTL_W_SMDS_Mesh::Perform()
 
   return aResult;
 }
+//================================================================================
+/*!
+ * \brief Destructor deletes temporary faces
+ */
+//================================================================================
+
+DriverSTL_W_SMDS_Mesh::~DriverSTL_W_SMDS_Mesh()
+{
+  for ( unsigned i = 0; i < myVolumeTrias.size(); ++i )
+    delete myVolumeTrias[i];
+}
+
+//================================================================================
+/*!
+ * \brief Finds free facets of volumes for which faces are missing in the mesh
+ */
+//================================================================================
+
+void DriverSTL_W_SMDS_Mesh::findVolumeTriangles()
+{
+  SMDS_VolumeTool myTool;
+  SMDS_VolumeIteratorPtr vIt = myMesh->volumesIterator();
+  while ( vIt->more() )
+  {
+    myTool.Set( vIt->next() );
+    for ( int iF = 0; iF < myTool.NbFaces(); ++iF )
+      if ( myTool.IsFreeFace( iF ))
+      {
+        const SMDS_MeshNode** n = myTool.GetFaceNodes(iF);
+        int                 nbN = myTool.NbFaceNodes(iF);
+        std::vector< const SMDS_MeshNode*> nodes( n, n+nbN );
+        if ( !myMesh->FindElement( nodes, SMDSAbs_Face, /*Nomedium=*/false))
+        {
+          int nbTria = nbN - 2;
+          for ( int iT = 0; iT < nbTria; ++iT )
+          {
+            myVolumeTrias.push_back( new SMDS_FaceOfNodes( n[0], n[1+iT], n[2+iT] ));
+          }
+        }
+      }
+  }
+}
+
+//================================================================================
+/*!
+ * \brief Return iterator on both faces in the mesh and on temporary faces
+ */
+//================================================================================
+
+SMDS_ElemIteratorPtr DriverSTL_W_SMDS_Mesh::getFaces() const
+{
+  SMDS_ElemIteratorPtr facesIter = myMesh->elementsIterator(SMDSAbs_Face);
+  SMDS_ElemIteratorPtr tmpTriaIter( new SMDS_ElementVectorIterator( myVolumeTrias.begin(),
+                                                                    myVolumeTrias.end()));
+  typedef std::vector< SMDS_ElemIteratorPtr > TElemIterVector;
+  TElemIterVector iters(2);
+  iters[0] = facesIter;
+  iters[1] = tmpTriaIter;
+  
+  typedef SMDS_IteratorOnIterators<const SMDS_MeshElement *, TElemIterVector> TItersIter;
+  return SMDS_ElemIteratorPtr( new TItersIter( iters ));
+}
 
 // static methods
 
@@ -110,35 +176,45 @@ static void writeFloat  ( const Standard_ShortReal& theVal,
   ofile.Write((char *)&entier,sizeof(u.c));
 }
 
-static gp_XYZ getNormale( const SMDS_MeshFace* theFace )
+static gp_XYZ getNormale( const SMDS_MeshNode* n1,
+                          const SMDS_MeshNode* n2,
+                          const SMDS_MeshNode* n3)
 {
-  gp_XYZ n;
+  SMESH_TNodeXYZ xyz1( n1 );
-  int aNbNode = theFace->NbNodes();
+  SMESH_TNodeXYZ xyz2( n2 );
-  TColgp_Array1OfXYZ anArrOfXYZ(1,4);
+  SMESH_TNodeXYZ xyz3( n3 );
-  gp_XYZ p1, p2, p3, p4;
+  gp_XYZ q1 = xyz2 - xyz1;
-  SMDS_ElemIteratorPtr aNodeItr = theFace->nodesIterator();
+  gp_XYZ q2 = xyz3 - xyz1;
-  int i = 1;
+  gp_XYZ n  = q1 ^ q2;
-  for ( ; aNodeItr->more() && i <= 4; i++ )
-  {
-    SMDS_MeshNode* aNode = (SMDS_MeshNode*)aNodeItr->next();
-    anArrOfXYZ.SetValue(i, gp_XYZ( aNode->X(), aNode->Y(), aNode->Z() ) );
-  }
-  
-  gp_XYZ q1 = anArrOfXYZ.Value(2) - anArrOfXYZ.Value(1);
-  gp_XYZ q2 = anArrOfXYZ.Value(3) - anArrOfXYZ.Value(1);
-  n  = q1 ^ q2;
-  if ( aNbNode > 3 )
-  {
-    gp_XYZ q3 = anArrOfXYZ.Value(4) - anArrOfXYZ.Value(1);
-    n += q2 ^ q3;
-  }
   double len = n.Modulus();
-  if ( len > 0 )
+  if ( len > std::numeric_limits<double>::min() )
     n /= len;
 
   return n;
 }
 
+//================================================================================
+/*!
+ * \brief Decompose a mesh face into triangles
+ *  \retval int - number of triangles
+ */
+//================================================================================
+
+static int getTriangles( const SMDS_MeshElement* face,
+                         const SMDS_MeshNode**   nodes)
+{
+  // WARNING: implementation must be coherent with counting triangles in writeBinary()
+  int nbN = face->NbCornerNodes();
+  const int nbTria = nbN-2;
+  for ( int i = 0; nbN > 1; --nbN )
+  {
+    nodes[ i++ ] = face->GetNode( 0 );
+    nodes[ i++ ] = face->GetNode( nbN-2 );
+    nodes[ i++ ] = face->GetNode( nbN-1 );
+  }
+  return nbTria;
+}
+
 // private methods
 
 Driver_Mesh::Status DriverSTL_W_SMDS_Mesh::writeAscii() const
@@ -152,17 +228,24 @@ Driver_Mesh::Status DriverSTL_W_SMDS_Mesh::writeAscii() const
 
   OSD_File aFile = OSD_File(OSD_Path(aFileName));
   aFile.Build(OSD_WriteOnly,OSD_Protection());
+
+  char sval[16];
   TCollection_AsciiString buf = TCollection_AsciiString ("solid\n");
   aFile.Write (buf,buf.Length());buf.Clear();
-  char sval[16];
 
-  SMDS_FaceIteratorPtr itFaces = myMesh->facesIterator();
+  const SMDS_MeshNode* triaNodes[2048];
 
-  for (; itFaces->more() ;) {
+  SMDS_ElemIteratorPtr itFaces = getFaces();
-    SMDS_MeshFace* aFace = (SMDS_MeshFace*)itFaces->next();
+  while ( itFaces->more() )
+  {
+    const SMDS_MeshElement* aFace = itFaces->next();
+    int nbTria = getTriangles( aFace, triaNodes );
     
-    if (aFace->NbNodes() == 3) {
+    for ( int iT = 0, iN = 0; iT < nbTria; ++iT )
-      gp_XYZ normale = getNormale( aFace );
+    {
+      gp_XYZ normale = getNormale( triaNodes[iN],
+                                   triaNodes[iN+1],
+                                   triaNodes[iN+2] );
 
       buf += " facet normal "; 
       sprintf (sval,"% 12e",normale.X());
@@ -178,9 +261,8 @@ Driver_Mesh::Status DriverSTL_W_SMDS_Mesh::writeAscii() const
       buf += "   outer loop\n"; 
       aFile.Write (buf,buf.Length());buf.Clear();
       
-      SMDS_ElemIteratorPtr aNodeIter = aFace->nodesIterator();
+      for ( int jN = 0; jN < 3; ++jN, ++iN ) {
-      for (; aNodeIter->more(); ) {
+        const SMDS_MeshNode* node = triaNodes[iN];
-        SMDS_MeshNode* node = (SMDS_MeshNode*)aNodeIter->next();
         buf += "     vertex "; 
         sprintf (sval,"% 12e",node->X());
         buf += sval;
@@ -219,38 +301,55 @@ Driver_Mesh::Status DriverSTL_W_SMDS_Mesh::writeBinary() const
   OSD_File aFile = OSD_File(OSD_Path(aFileName));
   aFile.Build(OSD_WriteOnly,OSD_Protection());
 
-  char sval[80];
-  Standard_Integer nbTri = 0;
-  SMDS_FaceIteratorPtr itFaces = myMesh->facesIterator();
-
   // we first count the number of triangles
-  for (;itFaces->more();) {
+  // WARNING: counting triangles must be coherent with getTriangles()
-    SMDS_MeshFace* aFace = (SMDS_MeshFace*)itFaces->next();
+  int nbTri = 0;
-    if (aFace->NbNodes() == 3)
+  const SMDS_MeshInfo& info = myMesh->GetMeshInfo();
-      nbTri++;
+  nbTri += info.NbTriangles();
+  nbTri += info.NbQuadrangles() * 2;
+  nbTri += myVolumeTrias.size();
+  if ( info.NbPolygons() > 0 )
+  {
+    SMDS_FaceIteratorPtr itFaces = myMesh->facesIterator();
+    while ( itFaces->more() )
+    {
+      const SMDS_MeshElement* aFace = itFaces->next();
+      if ( aFace->IsPoly() )
+        nbTri += aFace->NbNodes() - 2;
+    }
   }
 
+  // char sval[80]; -- avoid writing not initialized memory
+  TCollection_AsciiString sval(LABEL_SIZE-1,' ');
+  aFile.Write((Standard_Address)sval.ToCString(),LABEL_SIZE);
+
   // write number of triangles
-  //unsigned int NBT = nbTri;
-  aFile.Write((Standard_Address)sval,LABEL_SIZE);
   writeInteger(nbTri,aFile);  
 
-  // loop writing nodes. take face iterator again
+  // Loop writing nodes
+
   int dum=0;
-  itFaces = myMesh->facesIterator();
 
-  for (;itFaces->more();) {
+  const SMDS_MeshNode* triaNodes[2048];
-    SMDS_MeshFace* aFace = (SMDS_MeshFace*)itFaces->next();
 
-    if (aFace->NbNodes() == 3) {
+  SMDS_ElemIteratorPtr itFaces = getFaces();
-      gp_XYZ aNorm = getNormale( aFace );
+  while ( itFaces->more() )
-      writeFloat(aNorm.X(),aFile);
+  {
-      writeFloat(aNorm.Y(),aFile);
+    const SMDS_MeshElement* aFace = itFaces->next();
-      writeFloat(aNorm.Z(),aFile);
+    int nbTria = getTriangles( aFace, triaNodes );
     
-      SMDS_ElemIteratorPtr aNodeIter = aFace->nodesIterator();
+    for ( int iT = 0, iN = 0; iT < nbTria; ++iT )
-      for (; aNodeIter->more(); ) {
+    {
-        SMDS_MeshNode* node = (SMDS_MeshNode*)aNodeIter->next();
+      gp_XYZ normale = getNormale( triaNodes[iN],
+                                   triaNodes[iN+1],
+                                   triaNodes[iN+2] );
+      writeFloat(normale.X(),aFile);
+      writeFloat(normale.Y(),aFile);
+      writeFloat(normale.Z(),aFile);
+
+      for ( int jN = 0; jN < 3; ++jN, ++iN )
+      {
+        const SMDS_MeshNode* node = triaNodes[iN];
         writeFloat(node->X(),aFile);
         writeFloat(node->Y(),aFile);
         writeFloat(node->Z(),aFile);

src/DriverSTL/DriverSTL_W_SMDS_Mesh.h

@@ -30,13 +30,16 @@
 #include "SMESH_DriverSTL.hxx"
 
 #include "Driver_SMDS_Mesh.h"
-#include <Standard_TypeDef.hxx>
+#include "SMDS_ElemIterator.hxx"
+
+#include <vector>
 
 class MESHDRIVERSTL_EXPORT DriverSTL_W_SMDS_Mesh: public Driver_SMDS_Mesh
 {
  public:
   
   DriverSTL_W_SMDS_Mesh();
+  ~DriverSTL_W_SMDS_Mesh();
   virtual Status Perform();
   void    SetIsAscii( const bool theIsAscii = false );
 
@@ -44,10 +47,14 @@ class MESHDRIVERSTL_EXPORT DriverSTL_W_SMDS_Mesh: public Driver_SMDS_Mesh
   // PRIVATE METHODS
   Status  writeAscii  () const;
   Status  writeBinary () const;
+  void    findVolumeTriangles();
+
+  SMDS_ElemIteratorPtr getFaces() const;
 
  private:
   // PRIVATE FIELDS
   bool myIsAscii;
+  std::vector<const SMDS_MeshElement*> myVolumeTrias; // tmp triangles
 };
 
 #endif

src/DriverSTL/Makefile.am

@@ -53,6 +53,7 @@ libMeshDriverSTL_la_CPPFLAGS = \
         $(VTK_INCLUDES) \
 	$(BOOST_CPPFLAGS) \
 	-I$(srcdir)/../Driver \
+	-I$(srcdir)/../SMESH \
 	-I$(srcdir)/../SMDS
 
 libMeshDriverSTL_la_LDFLAGS  = \