C++ ON_NurbsCurve::SetCV方法代码示例

int ON_LineCurve::GetNurbForm(
      ON_NurbsCurve& c,
      double tolerance,
      const ON_Interval* subdomain
      ) const
{
  int rc = 0;
  if ( c.Create( m_dim==2?2:3, false, 2, 2 ) ) 
  {
    rc = 1;
    double t0 = m_t[0];
    double t1 = m_t[1];
    if (subdomain )
    {
      if ( t0 < t1 )
      {
        const ON_Interval& sd = *subdomain;
        double s0 = sd[0];
        double s1 = sd[1];
        if (s0 < t0) s0 = t0;
        if (s1 > t1) s1 = t1;
        if (s0 < s1)
        {
          t0 = s0;
          t1 = s1;
        }
        else
          rc = 0;
      }
      else
      {
        rc = 0;
      }
    }  
    if ( t0 < t1 )
    {
      c.m_knot[0] = t0;
      c.m_knot[1] = t1;
      c.SetCV( 0, PointAt(t0));
      c.SetCV( 1, PointAt(t1));
    }
    else if ( t0 > t1 )
    {
      rc = 0;
      c.m_knot[0] = t1;
      c.m_knot[1] = t0;
      c.SetCV( 0, PointAt(t1));
      c.SetCV( 1, PointAt(t0));
    }
    else
    {
      rc = 0;
      c.m_knot[0] = 0.0;
      c.m_knot[1] = 1.0;
      c.SetCV( 0, m_line.from );
      c.SetCV( 1, m_line.to );
    }
  }
  return rc;
}

ON_NurbsCurve
FittingCurve2d::initCPsNurbsCurve2D (int order, const vector_vec2d &cps)
{
  int cp_red = order - 2;
  ON_NurbsCurve nurbs;
  if (cps.size () < 3 || cps.size () < (2 * cp_red + 1))
  {
    printf ("[FittingCurve2d::initCPsNurbsCurve2D] Warning, number of control points too low.\n");
    return nurbs;
  }

  int ncps = cps.size () + 2 * cp_red; // +2*cp_red for smoothness and +1 for closing
  nurbs = ON_NurbsCurve (2, false, order, ncps);
  nurbs.MakePeriodicUniformKnotVector (1.0 / (ncps - order + 1));

  for (int j = 0; j < cps.size (); j++)
    nurbs.SetCV (cp_red + j, ON_3dPoint (cps[j] (0), cps[j] (1), 0.0));

  // close nurbs
  nurbs.SetCV (cp_red + cps.size (), ON_3dPoint (cps[0] (0), cps[0] (1), 0.0));

  // make smooth at closing point
  for (int j = 0; j < cp_red; j++)
  {
    ON_3dPoint cp;
    nurbs.GetCV (nurbs.CVCount () - 1 - cp_red + j, cp);
    nurbs.SetCV (j, cp);

    nurbs.GetCV (cp_red - j, cp);
    nurbs.SetCV (nurbs.CVCount () - 1 - j, cp);
  }

  return nurbs;
}

ON_NurbsCurve
FittingCurve2d::initCPsNurbsCurve2D (int order, const vector_vec2d &cps)
{
  ON_NurbsCurve nurbs;
  if ((int)cps.size () < (2 * order))
  {
    printf ("[FittingCurve2d::initCPsNurbsCurve2D] Warning, number of control points too low.\n");
    return nurbs;
  }

  int cp_red = order - 2;
  int ncps = cps.size () + cp_red;
  nurbs = ON_NurbsCurve (2, false, order, ncps);
  nurbs.MakePeriodicUniformKnotVector (1.0 / (ncps - order + 1));

  for (int j = 0; j < ncps; j++)
    nurbs.SetCV (j, ON_3dPoint (cps[j] (0), cps[j] (1), 0.0));

  for (int j = 0; j < cp_red; j++)
  {
    ON_3dPoint cp;
    nurbs.GetCV (nurbs.m_cv_count - 1 - cp_red + j, cp);
    nurbs.SetCV (j, cp);

    nurbs.GetCV (cp_red - j, cp);
    nurbs.SetCV (nurbs.m_cv_count - 1 - j, cp);
  }

  return nurbs;
}

ON_NurbsCurve
FittingCurve2d::initNurbsCurve2D (int order, const vector_vec2d &data, int ncps, double radiusF)
{
  if (data.empty ())
    printf ("[FittingCurve2d::initNurbsCurve2D] Warning, no boundary parameters available\n");

  Eigen::Vector2d mean = NurbsTools::computeMean (data);

  unsigned s = data.size ();

  double r (0.0);
  for (unsigned i = 0; i < s; i++)
  {
    Eigen::Vector2d d = data[i] - mean;
    double sn = d.squaredNorm ();
    if (sn > r)
      r = sn;
  }
  r = radiusF * sqrt (r);

  if (ncps < 2 * order)
    ncps = 2 * order;

  ON_NurbsCurve nurbs = ON_NurbsCurve (2, false, order, ncps);
  nurbs.MakePeriodicUniformKnotVector (1.0 / (ncps - order + 1));

  double dcv = (2.0 * M_PI) / (ncps - order + 1);
  Eigen::Vector2d cv;
  for (int j = 0; j < ncps; j++)
  {
    cv (0) = r * sin (dcv * j);
    cv (1) = r * cos (dcv * j);
    cv = cv + mean;
    nurbs.SetCV (j, ON_3dPoint (cv (0), cv (1), 0.0));
  }

  return nurbs;
}

ON_NurbsCurve
FittingCurve::initNurbsCurvePCA (int order, const vector_vec3d &data, int ncps, double rf)
{
  if (data.empty ())
    printf ("[FittingCurve::initNurbsCurvePCA] Warning, no boundary parameters available\n");

  Eigen::Vector3d mean;
  Eigen::Matrix3d eigenvectors;
  Eigen::Vector3d eigenvalues;

  unsigned s = unsigned (data.size ());

  NurbsTools::pca (data, mean, eigenvectors, eigenvalues);

  eigenvalues = eigenvalues / s; // seems that the eigenvalues are dependent on the number of points (???)

  double r = rf * sqrt (eigenvalues (0));

  if (ncps < 2 * order)
    ncps = 2 * order;

  ON_NurbsCurve nurbs = ON_NurbsCurve (3, false, order, ncps);
  nurbs.MakePeriodicUniformKnotVector (1.0 / (ncps - order + 1));

  double dcv = (2.0 * M_PI) / (ncps - order + 1);
  Eigen::Vector3d cv, cv_t;
  for (int j = 0; j < ncps; j++)
  {
    cv (0) = r * sin (dcv * j);
    cv (1) = r * cos (dcv * j);
    cv (2) = 0.0;
    cv_t = eigenvectors * cv + mean;
    nurbs.SetCV (j, ON_3dPoint (cv_t (0), cv_t (1), cv_t (2)));
  }

  return nurbs;
}

int 
ON_CurveProxy::GetNurbForm( // returns 0: unable to create NURBS representation
                 //            with desired accuracy.
                 //         1: success - returned NURBS parameterization
                 //            matches the curve's to wthe desired accuracy
                 //         2: success - returned NURBS point locus matches
                 //            the curve's to the desired accuracy but, on
                 //            the interior of the curve's domain, the 
                 //            curve's parameterization and the NURBS
                 //            parameterization may not match to the 
                 //            desired accuracy.
      ON_NurbsCurve& nurbs,
      double tolerance,  // (>=0)
      const ON_Interval* sub_domain  // OPTIONAL subdomain of ON::ProxyCurve::Domain()
      ) const
{
  ON_BOOL32 rc = false;
  if ( m_real_curve ) 
  {
    ON_Interval scratch_domain = RealCurveInterval( sub_domain );
    rc = m_real_curve->GetNurbForm(nurbs,tolerance,&scratch_domain);
    if ( rc )
    {
      if ( m_bReversed )
        nurbs.Reverse();
      ON_Interval d = m_this_domain;
      if ( sub_domain )
        d.Intersection( *sub_domain );
      nurbs.SetDomain( d[0], d[1] );

      if ( nurbs.m_dim <= 3 && nurbs.m_dim >= 1 )
      {
        double t0 = Domain()[0];
        double t1 = Domain()[1];
        if ( 0 != sub_domain )
        {
          if ( t0 < sub_domain->Min() )
            t0 = sub_domain->Min();
          if ( sub_domain->Max() < t1 )
            t1 = sub_domain->Max();
        }
        // set ends of NURBS curve to be exactly on ends of proxy curve
        ON_3dPoint P0 = PointAt(t0);
        ON_3dPoint P1 = PointAt(t1);
        ON_3dPoint N0 = nurbs.PointAtStart();
        ON_3dPoint N1 = nurbs.PointAtEnd();
				
				// 22 September 2003, GBA.  The end tuning code below should only  be applied
				//					to clamped nurbs curves.  In particular it should not be used on
				//					periodic nurbs curves.  Fixes TRR#11502.
				ON_BOOL32 clamped = nurbs.IsClamped(2);
        if ( clamped && (P0 != N0 || P1 != N1) )
        {
          if ( 0==nurbs.m_is_rat )
          {
            nurbs.SetCV(0,P0);
            nurbs.SetCV(nurbs.m_cv_count-1,P1);
          }
          else
          {
            ON_4dPoint H0, H1;
            H0 = P0;
            H0.w = nurbs.Weight(0);
            H0.x *= H0.w;
            H0.y *= H0.w;
            H0.z *= H0.w;
            nurbs.SetCV(0,H0);

            H1 = P1;
            H1.w = nurbs.Weight(nurbs.m_cv_count-1);
            H1.x *= H1.w;
            H1.y *= H1.w;
            H1.z *= H1.w;
            nurbs.SetCV(nurbs.m_cv_count-1,H1);
          }
        }
      }
    }
  }
  return rc;
}