From e87ef178c2e1dc6c003843a73cdb644e2747ff14 Mon Sep 17 00:00:00 2001
From: Daniele Bariletti <daniele.bariletti@egalware.comm>
Date: Tue, 10 Feb 2026 15:42:03 +0100
Subject: [PATCH] EgtGeomKernel : - correzione alla distanza punto- curva di
 bezier.

---
 DistPointCrvAux.cpp    | 17 +++++++++++++++--
 DistPointCrvBezier.cpp | 11 +++++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/DistPointCrvAux.cpp b/DistPointCrvAux.cpp
index fee8316..7afeb91 100644
--- a/DistPointCrvAux.cpp
+++ b/DistPointCrvAux.cpp
@@ -116,6 +116,7 @@ PolishMinDistPointCurve( const Point3d& ptP, const ICurve& cCurve,
       vtDiff = ptQ - ptP ;
      // angolo tra vettore e tangente
       dTemp = vtDer1 * vtDiff ;
+      bool bEquiverse = dTemp > 0 ;
       if ( abs( dTemp) > EPS_ZERO) 
          dSqCosA = dTemp * dTemp / ( vtDer1.SqLen() * vtDiff.SqLen()) ;
       else
@@ -123,8 +124,20 @@ PolishMinDistPointCurve( const Point3d& ptP, const ICurve& cCurve,
      // stima prossimo valore del parametro (Newton : Unext = U - F(U) / F'(U))
       dPrevPar = dPar ;
       dTemp = vtDer2 * vtDiff + vtDer1.SqLen() ;
-      if ( abs( dTemp) > EPS_ZERO)
-         dPar = dPrevPar - ( vtDer1 * vtDiff) / dTemp ;
+
+      // se il coseno tra questi due vettori è troppo grande potrei aver avuto una cattiva stima iniziale
+      // provo quindi ad aggiustare a mano, anziché usare il segno suggerito da newton, che con queste premesse potrebbe divergere
+      double dCos75 = 0.2588 ;
+      if ( abs( dTemp) > EPS_ZERO) {
+         double dDelta = ( vtDer1 * vtDiff) / dTemp ;
+         if ( dSqCosA > dCos75) {
+            if ( ( bEquiverse  &&  dDelta > 0)  ||  ( ! bEquiverse  &&  dDelta < 0))
+               dDelta *= -1 ;
+            dPar = dPrevPar + dDelta ;
+         }
+         else
+            dPar = dPrevPar - dDelta ;
+      }
      // clipping parametro
       if ( dPar < approxMin.dParMin) {
          if ( approxMin.bParMinSing  &&  ! bClampedFromSing) {
diff --git a/DistPointCrvBezier.cpp b/DistPointCrvBezier.cpp
index 9c324a5..6106698 100644
--- a/DistPointCrvBezier.cpp
+++ b/DistPointCrvBezier.cpp
@@ -42,6 +42,17 @@ DistPointCrvBezier::DistPointCrvBezier( const Point3d& ptP, const ICurveBezier&
    if ( ! CrvBez.ApproxWithLines( dLinTol, ANG_TOL_APPROX_DEG, ICurve::APL_STD, PL))
       return ;
 
+   int nDeg = CrvBez.GetDegree() ;
+   if ( PL.GetPointNbr() < nDeg + 1) {
+      // costruisco una polilinea con un numero di curve scelto in base al grado della curva
+      PL.Clear() ; 
+      for ( int i = 0 ; i <= nDeg + 1 ; ++i) {
+         double dU = double(i) / (nDeg + 1) ;
+         Point3d ptBez ;
+         CrvBez.GetPointD1D2( dU, ICurve::Side::FROM_MINUS, ptBez) ;
+         PL.AddUPoint( dU, ptBez) ;
+      }
+   }
   // cerco la minima distanza per la polilinea
    MDCVECTOR vApproxMin ;
    if ( ! CalcMinDistPointPolyLine( ptP, PL, dLinTol, vApproxMin))