//----------------------------------------------------------------------------
//  EgalTech 2013-2014
//----------------------------------------------------------------------------
// File : SceneGeom.cpp       Data : 10.02.14          Versione : 1.5b1
// Contenuto : Implementazione della gestione geometria della classe scena.
//
//
//
// Modifiche : 10.02.14 DS Creazione modulo.
//
//
//----------------------------------------------------------------------------

//--------------------------- Include ----------------------------------------
#include "stdafx.h"
#include "Scene.h"
#include "ObjOldGraphics.h"
#include "ObjNewGraphics.h"
#include "EGrUtils.h"
#include "/EgtDev/Include/EgtILogger.h"
#include "/EgtDev/Include/EGnStringUtils.h"
#include "/EgtDev/Include/EGkFrame3d.h"
#include "/EgtDev/Include/EgtPointerOwner.h"
#include "/EgtDev/Include/EGkGdbIterator.h"
#include "/EgtDev/Include/EGkGeoVector3d.h"
#include "/EgtDev/Include/EGkGeoPoint3d.h"
#include "/EgtDev/Include/EGkCurve.h"
#include "/EgtDev/Include/EGkCurveComposite.h"
#include "/EgtDev/Include/EGkSurfTriMesh.h"
#include "/EgtDev/Include/EGkExtText.h"
#include "/EgtDev/Include/EGkGdbFunct.h"

using namespace std ;

//------------------------------ Local functions -----------------------------
static ObjEGrGraphics* CreateObjEGrGraphics( bool bNewWay) ;
static bool CalcCurveTailMark( const Vector3d& vtRef, const PolyLine& plCrv, PolyLine& plMark) ;
static bool CalcCurveTipArrow( const Vector3d& vtRef, const PolyLine& plCrv, PolyLine& plArr) ;
static bool CalcConnectingLines( const PolyLine& plCrv, const Vector3d& vtTh, bool bDense, PNTVECTOR& vPnt) ;

//----------------------------------------------------------------------------
bool
Scene::UpdateExtension( void)
{
   BBox3d b3Ext ;
   if ( m_pGeomDB == nullptr  ||  ! m_pGeomDB->GetLocalBBox( GDB_ID_ROOT, b3Ext, BBF_ONLY_VISIBLE))
      return false ;
   return SetExtension( b3Ext) ;
}

//----------------------------------------------------------------------------
bool
Scene::SetMark( Color colMark)
{
   m_colMark = colMark ;

   return true ;
}

//----------------------------------------------------------------------------
bool
Scene::SetSelSurf( Color colSelSurf)
{
   m_colSelSurf = colSelSurf ;

   return true ;
}

//----------------------------------------------------------------------------
bool
Scene::DrawGroup( int nId, int nPass, const MdStMkCol& cParent)
{
  // creo un iteratore
   PtrOwner<IGdbIterator> pIter( CreateGdbIterator( m_pGeomDB)) ;
   if ( IsNull( pIter))
      return false ;

  // recupero il gruppo
   if ( ! pIter->GoTo( nId))
      return false ;

  // eseguo il disegno
   return DrawGroup( *pIter, nPass, cParent) ;
}

//----------------------------------------------------------------------------
bool
Scene::DrawGroup( const IGdbIterator& iIter, int nPass, const MdStMkCol& cParent)
{
  // creo un iteratore
   PtrOwner<IGdbIterator> pIter( CreateGdbIterator( m_pGeomDB)) ;
   if ( IsNull( pIter))
      return false ;
  // recupero il riferimento del gruppo
   Frame3d frFrame ;
   if ( ! iIter.GetGroupFrame( frFrame))
      return false ;
  // se non è identità, lo aggiungo sullo stack delle matrici MODELVIEW di OpenGL
   bool bMatrix = ( frFrame.GetType() != Frame3d::TOP  ||  ! frFrame.Orig().IsSmall()) ;
   if ( bMatrix) {
      glPushMatrix() ;
      double Matrix[OGLMAT_DIM] ;
      if ( FrameToOpenGlMatrix( frFrame, Matrix))
         glMultMatrixd( Matrix) ;
   }                                
  // scandisco il gruppo
   bool bOk = true ;
   for ( bool bNext = pIter->GoToFirstInGroup( iIter) ;
         bNext  &&  bOk ;
         bNext = pIter->GoToNext()) {
     // leggo il tipo di oggetto
      int nGdbType = pIter->GetGdbType() ;
     // recupero e aggiorno il modo dell'oggetto
      int nMode = GDB_MD_STD ;
      pIter->GetMode( nMode) ;
      nMode = ::CalcMode( nMode, cParent.nMode) ;
     // recupero e aggiorno lo stato dell'oggetto
      int nStat = GDB_ST_ON ;
      pIter->GetStatus( nStat) ;
      nStat = ::CalcStatus( nStat, cParent.nStat) ;
      nStat = ::AdjustStatusWithMode( nStat, nMode) ;
     // recupero e aggiorno la marcatura dell'oggetto
      int nMark = GDB_MK_OFF ;
      pIter->GetMark( nMark) ;
      nMark = ::CalcMark( nMark, cParent.nMark) ;
     // recupero e aggiorno il colore dell'oggetto
      Color colObj = cParent.colObj ;
      pIter->GetMaterial( colObj) ;
     // se in modalità selezione, verifico sia selezionabile
      bool bSel = true ;
      if ( m_bSelect  &&  UnselectableFind( pIter->GetId()))
         bSel = false ;
     // se oggetto geometrico
      if ( nGdbType == GDB_TY_GEO) {
        // se non nascosto e selezionabile, lo disegno
         if ( nStat != GDB_ST_OFF  &&  bSel) {
            if ( ! DrawGeoObj( *pIter, nPass, MdStMkCol( nMode, nStat, nMark, colObj)))
               bOk = false ;
         }
      }
     // se gruppo
      else if ( nGdbType == GDB_TY_GROUP) {
        // se non nascosto e selezionabile, lo disegno
         if ( nStat != GDB_ST_OFF  &&  bSel) {
            if ( ! DrawGroup( *pIter, nPass, MdStMkCol( nMode, nStat, nMark, colObj)))
               bOk = false ;
         }
      }
   }
  // se necessario, ripristino lo stack delle matrici
   if ( bMatrix)
      glPopMatrix() ;

   return bOk ;
}

//----------------------------------------------------------------------------
bool
Scene::DrawGeoObj( const IGdbIterator& iIter, int nPass, const MdStMkCol& siObj)
{
  // recupero l'oggetto geometrico e il suo tipo
   IGeoObj* pGeoObj = (const_cast<IGdbIterator*>(&iIter))->GetGeoObj() ;
   if ( pGeoObj == nullptr)
      return false ;
   int nGeoType = pGeoObj->GetType() ;

  // recupero eventuale parte custom
   const IUserObj* pUserObj = iIter.GetUserObj() ;

  // se non esiste grafica associata, la creo
   if ( pGeoObj->GetObjGraphics() == nullptr) {
     // nuova modalità grafica solo per superfici con molti triangoli
      const int N_MIN_TRIA_NEWWAY = 100 ; 
      bool bNewWay = false ;
      if ( m_bNewWay  &&  nGeoType == SRF_TRIMESH) {
         const ISurfTriMesh* pSTM = GetSurfTriMesh( pGeoObj) ;
         if ( pSTM != nullptr  &&  pSTM->GetTriangleNum() > N_MIN_TRIA_NEWWAY)
            bNewWay = true ;
      }  
      ObjEGrGraphics* pGraphics = CreateObjEGrGraphics( bNewWay) ;
      if ( pGraphics == nullptr)
         return false ;
      pGraphics->SetScene( this) ;
      pGeoObj->SetObjGraphics( pGraphics) ;
   }

  // se la grafica associata non è valida la ricalcolo
   ObjEGrGraphics* pGraphics = GetObjEGrGraphics( pGeoObj) ;
   if ( ! pGraphics->IsValid()) {
     // se vettore
      if ( nGeoType == GEO_VECT3D) {
        // recupero il vettore
         const IGeoVector3d* pVector = GetGeoVector3d( pGeoObj) ;
         if ( pVector == nullptr)
            return false ;
        // calcolo la grafica
         pGraphics->Clear() ;
         pGraphics->AddColor( siObj.colObj) ;
         PolyLine PL ;
         if ( pVector->GetDrawWithArrowHead( 0.1, 10, PL))
            pGraphics->AddPolyLine(PL) ;
         else
            pGraphics->AddPoint( pVector->GetBase()) ;
      }
     // se punto
      else if ( nGeoType == GEO_PNT3D) {
        // recupero il punto
         const IGeoPoint3d* pPoint = GetGeoPoint3d( pGeoObj) ;
         if ( pPoint == nullptr)
            return false ;
        // calcolo la grafica
         pGraphics->Clear() ;
         pGraphics->AddColor( siObj.colObj) ;
         pGraphics->AddPoint( pPoint->GetPoint()) ;
      }
     // se riferimento
      else if ( nGeoType == GEO_FRAME3D) {
        // recupero il riferimento
         const IGeoFrame3d* pFrame = GetGeoFrame3d( pGeoObj) ;
         if ( pFrame == nullptr)
            return false ;
        // aggiorno la grafica (colori speciali)
         PolyLine plX, plY, plZ ;
         pFrame->GetDrawWithArrowHeads( 10, 0.1, plX, plY, plZ) ;
         pGraphics->Clear() ;
         pGraphics->AddColor( RED) ;
         pGraphics->AddPolyLine( plX) ; 
         pGraphics->AddColor( LIME) ;
         pGraphics->AddPolyLine( plY) ; 
         pGraphics->AddColor( BLUE) ;
         pGraphics->AddPolyLine( plZ) ; 
      }
     // se curva
      else if ( ( nGeoType & GEO_CURVE) != 0) {
        // recupero la curva
         const ICurve* pCurve = GetCurve( pGeoObj) ;
         if ( pCurve == nullptr)
            return false ;
        // calcolo la grafica
         PolyLine PL ;
         pCurve->ApproxWithLines( 0.005, 5, PL) ;
         pGraphics->Clear() ;
         pGraphics->AddColor( siObj.colObj) ;
         pGraphics->AddPolyLine( PL) ; 
         // eventuali segni ausiliari (mark, frecce, ...)
         Vector3d vtRef ;
         if ( ! pCurve->GetExtrusion( vtRef)  ||  vtRef.IsSmall())
            vtRef = Z_AX ;
         PolyLine PLM ;
         if ( CalcCurveTailMark( vtRef, PL, PLM))
            pGraphics->AddPolyLine( PLM, true) ; 
         PolyLine PLA ;
         if ( CalcCurveTipArrow( vtRef, PL, PLA))
            pGraphics->AddPolyLine( PLA, true) ; 
         // eventuale spessore
         double dTh ;
         Vector3d vtExtr ;
         if ( pCurve->GetExtrusion( vtExtr)  &&  ! vtExtr.IsSmall()  &&
              pCurve->GetThickness( dTh)  &&  fabs( dTh) > EPS_SMALL) {
           // segmenti di raccordo
            PNTVECTOR vPnt ;
            bool bDense = ( nGeoType == CRV_ARC  ||  nGeoType == CRV_BEZ) ;
            if ( CalcConnectingLines( PL, dTh * vtExtr, bDense, vPnt))
               pGraphics->AddLines( vPnt) ;
           // percorso traslato
            PL.Translate( dTh * vtExtr) ;
            pGraphics->AddPolyLine( PL) ;
         }
      }
     // se superficie trimesh
      else if ( nGeoType == SRF_TRIMESH) {
        // recupero la superficie
         const ISurfTriMesh* pSTM = GetSurfTriMesh( pGeoObj) ;
         if ( pSTM == nullptr)
            return false ;
         // recupero il materiale
         Material mMat ;
         if ( ! iIter.GetCalcMaterial( mMat))
            mMat.Set( m_colDef) ;
        // impostazioni iniziali
         pGraphics->Clear() ;
         pGraphics->AddColor( siObj.colObj) ;  // per wireframe
         pGraphics->AddMaterial( mMat.GetAmbient(), mMat.GetDiffuse(),
                                 mMat.GetSpecular(), mMat.GetShininess()) ;
         pGraphics->AddBackMaterial( GetSurfBackColor( mMat.GetDiffuse())) ;
         pGraphics->StartTriangles( pSTM->GetTriangleNum()) ;
        // ciclo sui triangoli della superficie
         Triangle3d Tria ;
         TriFlags3d TFlags ;
         TriNormals3d TNrms ;
         int nId = pSTM->GetFirstTriangle( Tria) ;
         while ( nId != SVT_NULL) {
           // se visualizzazione avanzata : edge solo se boundary e normali ai vertici smussate
            if ( m_bShowTriaAdvanced) {
               pSTM->GetTriangleBoundaryEdges( nId, TFlags) ;
               pSTM->GetTriangleSmoothNormals( nId, TNrms) ;
            }
           // altrimenti : tutti gli edge e normali ai vertici prendono quella del triangolo
            else {
               for ( int i = 0 ; i < 3 ; ++i) {
                  TFlags.bFlag[i] = true ;
                  TNrms.vtN[i] = Tria.GetN() ;
               }
            }
            pGraphics->AddTriangle( Tria, TFlags, TNrms) ;
            nId = pSTM->GetNextTriangle( nId, Tria) ;
         }
         pGraphics->EndTriangles() ;
      }
     // se testo
      else if ( nGeoType == EXT_TEXT) {
        // recupero il testo
         const IExtText* pTXT = GetExtText( pGeoObj) ;
         if ( pTXT == nullptr)
            return false ;
        // calcolo la grafica
         POLYLINELIST lstPL ;
         pTXT->ApproxWithLines( 0.01, 5, lstPL) ;
         pGraphics->Clear() ;
         pGraphics->AddColor( siObj.colObj) ;
         for ( const auto& PL : lstPL)
            pGraphics->AddPolyLine( PL) ; 
      }
     // se esiste parte custom
      if ( pUserObj != nullptr) {
         POLYLINELIST lstPL ;
         if ( pUserObj->GetDrawPolyLines( lstPL)) {
            for ( const auto& PL : lstPL)
               pGraphics->AddPolyLine( PL, true) ; 
         }
      }
   }

  // se richiesto, visualizzo la grafica associata
   bool bShowAux = false ;
   if ( (( nGeoType & GEO_CURVE) != 0  ||  pUserObj != nullptr)  &&  m_bShowCurveDirection)
      bShowAux = true ;

  // recupero il valore di opacità (solo per le superfici può esserci trasparenza)
   int nAlpha = siObj.colObj.GetIntAlpha() ;

  // se hiddenline e non selezione
   if ( m_nShowMode == SM_HIDDENLINE  &&  ! m_bSelect) {
     // in prima passata disegno solo le superfici opache
      if ( nPass == 1  &&  ( ( nGeoType & GEO_SURF) == 0  ||  nAlpha <= ALPHA_LIM))
         return true ;
   }

  // se shading e non modalità selezione
   bool bSurfSha = false ;
   if ( m_nShowMode == SM_SHADING  &&  ! m_bSelect) {
     // in prima passata disegno solo le superfici opache e metto in un vettore quelle semitrasparenti
      if ( nPass == 1) {
         if ( ( nGeoType & GEO_SURF) == 0)
            return true ;
         else {
            if ( nAlpha > ALPHA_LIM)
               bSurfSha = true ;
            else {
              // recupero matrice MODELVIEW corrente
               GLdouble ModelView[ OGLMAT_DIM] ;
               glGetDoublev( GL_MODELVIEW_MATRIX, ModelView) ;
               Frame3d frModView ;
               OpenGlMatrixToFrame( ModelView, frModView) ;
              // recupero il box dell'oggetto e lo porto nel riferimento MODELVIEW
               BBox3d b3Box ;
               pGraphics->GetLocalBBox( b3Box) ;
               b3Box.ToGlob( frModView) ;
              // inserisco i dati nel vettore
               m_vAlphaSurf.emplace_back( frModView, pGraphics, siObj.nStat, siObj.nMark,
                                          nAlpha, bShowAux, b3Box.GetMin().z, b3Box.GetMax().z) ;
               return true ;
            }
         }
      }
     // in seconda passata disegno solo dimensioni 0 e curve
      if ( nPass == 2  &&  ( nGeoType & GEO_SURF) != 0)
         return true ;
   }

  // se in selezione
   if ( m_bSelect) {
     // vaglio per il filtro di tipo
      if ( ( nGeoType & m_nObjFilterForSelect) == 0)
         return true ;
     // carico il nome
      glLoadName( iIter.GetId()) ;
   }

  // eseguo visualizzazione
   return pGraphics->Draw( siObj.nStat, siObj.nMark, bSurfSha, nAlpha, bShowAux) ;
}

//----------------------------------------------------------------------------
bool
Scene::DrawAlphaSurfVector( void)
{
  // ordino vettore in senso crescente secondo Zmax (asse Z punta verso osservatore)
   sort( m_vAlphaSurf.begin(), m_vAlphaSurf.end(), 
         []( const AlphaSurf& a, const AlphaSurf&b) { return a.dZmax < b.dZmax ; }) ;

  // eseguo visualizzazione
   for ( const auto& AlphaSurf : m_vAlphaSurf) {
     // imposto matrice MODELVIEW
      double Matrix[OGLMAT_DIM] ;
      FrameToOpenGlMatrix( AlphaSurf.frModView, Matrix) ;
      glPushMatrix() ;
      glLoadMatrixd( Matrix) ;
     // eseguo visualizzazione
      bool bOk = AlphaSurf.pGraph->Draw( AlphaSurf.nStat, AlphaSurf.nMark, true,
                                         AlphaSurf.nAlpha, AlphaSurf.bShowAux) ;
     // ripristino matrice
      glPopMatrix() ;
     // in caso di errore, esco
      if ( ! bOk)
         return false ;
   }
   return true ;
}

//----------------------------------------------------------------------------
bool
Scene::DeleteObjGraphicsGroup( int nId)
{
  // creo un iteratore
   PtrOwner<IGdbIterator> pIter( CreateGdbIterator( m_pGeomDB)) ;
   if ( IsNull( pIter))
      return false ;
  // scandisco il gruppo
   bool bNext = pIter->GoToFirstInGroup( nId) ;
   while ( bNext) {
     // leggo il tipo di nodo
      int nGdbType = pIter->GetGdbType() ;
     // se oggetto geometrico
      if ( nGdbType == GDB_TY_GEO) {
        // lo recupero
         IGeoObj* pGeoObj = pIter->GetGeoObj() ;
         if ( pGeoObj == nullptr)
            return false ;
        // ne cancello l'eventuale parte grafica
         ObjEGrGraphics* pGraph = GetObjEGrGraphics( pGeoObj) ;
         if ( pGraph != nullptr  &&  pGraph->GetScene() == this)
            pGeoObj->SetObjGraphics( nullptr) ;
      }
     // se gruppo
      else if ( nGdbType == GDB_TY_GROUP) {
        // ripeto sugli oggetti dello stesso
         if ( ! DeleteObjGraphicsGroup( pIter->GetId()))
            return false ;
      }
     // passo al successivo
      bNext = pIter->GoToNext() ;
   }

   return true ;
}

//------------------------------ Local functions -----------------------------
//----------------------------------------------------------------------------
static ObjEGrGraphics*
CreateObjEGrGraphics( bool bNewWay)
{
   if ( bNewWay)
      return ( new ObjNewGraphics) ;
   else
      return ( new ObjOldGraphics) ;
}

//----------------------------------------------------------------------------
static bool
CalcCurveTailMark( const Vector3d& vtRef, const PolyLine& plCrv, PolyLine& plMark)
{
  // pulisco la polilinea per il segno
   plMark.Clear() ;
  // verifico effettiva esistenza della polilinea approssimante la curva
   if ( plCrv.GetLineNbr() < 1)
      return false ;
  // dimensioni limite traverso
   const double MAX_LEN_TR = 6 ;
   const double MIN_LEN_TR = 0.1 ;
  // recupero dati primo tratto della curva
   Point3d ptTail, ptP ;
   if ( ! plCrv.GetFirstLine( ptTail, ptP))
      return false ;
   Vector3d vtDir = ptP - ptTail ;
   double dLen = vtDir.Len() ;
   if ( dLen < EPS_SMALL)
      return false ;
   vtDir /= dLen ;
   // se molto piccolo, cerco di allungarmi senza deviare troppo
   while ( dLen < MAX_LEN_TR) {
      Point3d ptP1, ptP2 ;
      if ( ! plCrv.GetNextLine( ptP1, ptP2))
         break ;
      Vector3d vtNxDir = ptP2 - ptP1 ;
      vtNxDir.Normalize() ;
      if ( ( vtDir * vtNxDir) > cos( 30 * DEGTORAD))
         dLen = (ptP1 - ptTail).Len() ;
      else
         break ;
   }
  // recupero lunghezza del percorso
   double dLenRef = 0 ;
   plCrv.GetApproxLength( dLenRef) ;
  // lunghezza della freccia
  // calcolo dimensioni traverso
   const double TR_COEFF = 0.6 ;
   const double LEN_COEFF = 0.15 ;
   double dLenTr = TR_COEFF * min( LEN_COEFF * dLenRef, dLen)  ;
   if ( dLenTr > MAX_LEN_TR)
      dLenTr = MAX_LEN_TR ;
   else if ( dLenTr < MIN_LEN_TR)
      dLenTr = MIN_LEN_TR ;
  // disegno traverso
   Frame3d frF ;
   if ( frF.Set( ptTail, vtDir, vtRef)) {
      Point3d ptP0 = ORIG + Vector3d( 0, 0.5 * dLenTr, 0) ;
      ptP0.ToGlob( frF) ;
      plMark.AddUPoint( 0, ptP0) ;
      Point3d ptP1 = ORIG + Vector3d( 0, - 0.5 * dLenTr, 0) ;
      ptP1.ToGlob( frF) ;
      plMark.AddUPoint( 1, ptP1) ;
   }
   else {
      frF.Set( ptTail, vtDir) ;
      Point3d ptP0 = ORIG + Vector3d( - 0.5 * dLenTr, - 0.5 * dLenTr, 0) ;
      ptP0.ToGlob( frF) ;
      plMark.AddUPoint( 0, ptP0) ;
      Point3d ptP1 = ORIG + Vector3d( 0.5 * dLenTr, - 0.5 * dLenTr, 0) ;
      ptP1.ToGlob( frF) ;
      plMark.AddUPoint( 1, ptP1) ;
      Point3d ptP2 = ORIG + Vector3d( 0.5 * dLenTr, 0.5 * dLenTr, 0) ;
      ptP2.ToGlob( frF) ;
      plMark.AddUPoint( 2, ptP2) ;
      Point3d ptP3 = ORIG + Vector3d( - 0.5 * dLenTr, 0.5 * dLenTr, 0) ;
      ptP3.ToGlob( frF) ;
      plMark.AddUPoint( 3, ptP3) ;
      // punto di chiusura coincidente con il primo
      plMark.AddUPoint( 4, ptP0) ;
   }
   return true ;
}

//----------------------------------------------------------------------------
static bool
CalcCurveTipArrow( const Vector3d& vtRef, const PolyLine& plCrv, PolyLine& plArr)
{
  // pulisco la polilinea per la freccia
   plArr.Clear() ;
  // verifico effettiva esistenza della polilinea approssimante la curva
   if ( plCrv.GetLineNbr() < 1)
      return false ;
  // dimensioni freccia limite
   const double MAX_LEN_ARR = 10.0 ;
   const double MIN_LEN_ARR = 0.1 ;
  // recupero dati ultimo tratto della curva
   Point3d ptTip, ptP ;
   if ( ! plCrv.GetLastLine( ptP, ptTip))
      return false ;
   Vector3d vtDir = ptTip - ptP ;
   double dLen = vtDir.Len() ;
   if ( dLen < EPS_SMALL)
      return false ;
   vtDir /= dLen ;
   // se molto piccolo, cerco di allungarmi senza deviare troppo
   while ( dLen < MAX_LEN_ARR) {
      Point3d ptP1, ptP2 ;
      if ( ! plCrv.GetPrevLine( ptP1, ptP2))
         break ;
      Vector3d vtPrDir = ptP2 - ptP1 ;
      vtPrDir.Normalize() ;
      if ( ( vtDir * vtPrDir) > cos( 30 * DEGTORAD))
         dLen = (ptTip - ptP1).Len() ;
      else
         break ;
   }
  // recupero lunghezza del percorso
   double dLenRef = 0 ;
   plCrv.GetApproxLength( dLenRef) ;
  // lunghezza della freccia
   const double LEN_COEFF = 0.15 ;
   double dLenArr = min( LEN_COEFF * dLenRef, dLen) ;
   if ( dLenArr > MAX_LEN_ARR)
      dLenArr = MAX_LEN_ARR ;
   else if ( dLenArr < MIN_LEN_ARR)
      dLenArr = MIN_LEN_ARR ;
  // disegno freccia
   const double A_WIDTH_COEFF = 0.3 ;
   Frame3d frF ;
   if ( ! frF.Set( ptTip, vtDir, vtRef))
      frF.Set( ptTip, vtDir) ;
   plArr.AddUPoint( 0, ptTip) ;
   Point3d ptP1 = ORIG + Vector3d( 0, A_WIDTH_COEFF, -1) * dLenArr ;
   ptP1.ToGlob( frF) ;
   plArr.AddUPoint( 1, ptP1) ;
   Point3d ptP2 = ORIG + Vector3d( 0, - A_WIDTH_COEFF, -1) * dLenArr ;
   ptP2.ToGlob( frF) ;
   plArr.AddUPoint( 2, ptP2) ;
   plArr.AddUPoint( 3, ptTip) ;
      
   return true ;
}

//----------------------------------------------------------------------------
static bool
CalcConnectingLines( const PolyLine& plCrv, const Vector3d& vtTh, bool bDense, PNTVECTOR& vPnt)
{
  // assegno coefficiente
   double dDelta = ( bDense ? 0.25 : 1) ;
  // ciclo per creare i segmenti di raccordo
   double dU, dUprev = - dDelta ;
   vPnt.reserve( 5) ;
   for ( bool bFound = plCrv.GetFirstU( dU) ; bFound ; bFound = plCrv.GetNextU( dU)) {
      if ( ( dU - dUprev) > dDelta - EPS_PARAM) {
         Point3d ptP ;
         plCrv.GetCurrPoint( ptP) ;
         vPnt.push_back( ptP) ;
         ptP += vtTh ;
         vPnt.push_back( ptP) ;
         dUprev += dDelta ;
      }
   }
   return true ;
}