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panda/src/egg/eggNurbsCurve.I

Go to the documentation of this file.

// Filename: eggNurbsCurve.I
// Created by:  drose (15Feb00)
//
////////////////////////////////////////////////////////////////////
//
// PANDA 3D SOFTWARE
// Copyright (c) 2001, Disney Enterprises, Inc.  All rights reserved
//
// All use of this software is subject to the terms of the Panda 3d
// Software license.  You should have received a copy of this license
// along with this source code; you will also find a current copy of
// the license at http://www.panda3d.org/license.txt .
//
// To contact the maintainers of this program write to
// panda3d@yahoogroups.com .
//
////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsCurve::Constructor
//       Access: Public
//  Description:
////////////////////////////////////////////////////////////////////
INLINE EggNurbsCurve::
EggNurbsCurve(const string &name) : EggCurve(name) {
  _order = 0;
}

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsCurve::Copy constructor
//       Access: Public
//  Description:
////////////////////////////////////////////////////////////////////
INLINE EggNurbsCurve::
EggNurbsCurve(const EggNurbsCurve &copy) :
  EggCurve(copy),
  _knots(copy._knots),
  _order(copy._order)
{
}

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsCurve::Copy assignment operator
//       Access: Public
//  Description:
////////////////////////////////////////////////////////////////////
INLINE EggNurbsCurve &EggNurbsCurve::
operator = (const EggNurbsCurve &copy) {
  EggCurve::operator = (copy);
  _knots = copy._knots;
  _order = copy._order;
  return *this;
}

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsCurve::set_order
//       Access: Public
//  Description: Directly changes the order to the indicated value
//               (which must be an integer in the range 1 <= order <=
//               4).  If possible, it is preferable to use the setup()
//               method instead of this method, since changing the
//               order directly may result in an invalid curve.
////////////////////////////////////////////////////////////////////
INLINE void EggNurbsCurve::
set_order(int order) {
  nassertv(order >= 1 && order <= 4);
  _order = order;
}

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsCurve::set_knot
//       Access: Public
//  Description: Resets the value of the indicated knot as indicated.
//               k must be in the range 0 <= k < get_num_knots(),
//               and the value must be in the range get_knot(k - 1)
//               <= value <= get_knot(k + 1).
////////////////////////////////////////////////////////////////////
INLINE void EggNurbsCurve::
set_knot(int k, double value) {
  nassertv(k >= 0 && k < (int)_knots.size());
  _knots[k] = value;
}

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsCurve::get_order
//       Access: Public
//  Description: Returns the order of the curve.  The order is the
//               degree of the NURBS equation plus 1; for a typical
//               NURBS, the order is 4.  With this implementation of
//               NURBS, the order must be in the range [1, 4].
////////////////////////////////////////////////////////////////////
INLINE int EggNurbsCurve::
get_order() const {
  return _order;
}

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsCurve::get_degree
//       Access: Public
//  Description: Returns the degree of the curve.  For a typical
//               NURBS, the degree is 3.
////////////////////////////////////////////////////////////////////
INLINE int EggNurbsCurve::
get_degree() const {
  return _order - 1;
}

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsCurve::get_num_knots
//       Access: Public
//  Description: Returns the number of knots.
////////////////////////////////////////////////////////////////////
INLINE int EggNurbsCurve::
get_num_knots() const {
  return _knots.size();
}

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsCurve::get_num_cvs
//       Access: Public
//  Description: Returns the total number of control vertices that
//               *should* be defined for the curve.  This is
//               determined by the number of knots and the order, in
//               each direction; it does not necessarily reflect the
//               number of vertices that have actually been added to
//               the curve.  (However, if the number of vertices in
//               the curve are wrong, the curve is invalid.)
////////////////////////////////////////////////////////////////////
INLINE int EggNurbsCurve::
get_num_cvs() const {
  return get_num_knots() - get_order();
}

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsCurve::get_knot
//       Access: Public
//  Description: Returns the nth knot value defined.
////////////////////////////////////////////////////////////////////
INLINE double EggNurbsCurve::
get_knot(int k) const {
  nassertr(k >= 0 && k < (int)_knots.size(), 0.0);
  return _knots[k];
}

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