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panda/src/egg/eggNurbsSurface.cxx

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// Filename: eggNurbsSurface.cxx
// 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 .
//
////////////////////////////////////////////////////////////////////

#include "eggNurbsSurface.h"

#include <indent.h>

TypeHandle EggNurbsSurface::_type_handle;

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsSurface::setup
//       Access: Public
//  Description: Prepares a new surface definition with the indicated
//               order and number of knots in each dimension.  This
//               also implies a particular number of vertices in each
//               dimension as well (the number of knots minus the
//               order), but it is up to the user to add the correct
//               number of vertices to the surface by repeatedly
//               calling push_back().
////////////////////////////////////////////////////////////////////
void EggNurbsSurface::
setup(int u_order, int v_order,
      int num_u_knots, int num_v_knots) {
  _u_order = u_order;
  _v_order = v_order;
  _u_knots.clear();
  _v_knots.clear();

  int i;
  _u_knots.reserve(num_u_knots);
  for (i = 0; i < num_u_knots; i++) {
    _u_knots.push_back((double)i);
  }
  _v_knots.reserve(num_v_knots);
  for (i = 0; i < num_v_knots; i++) {
    _v_knots.push_back((double)i);
  }
}

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsSurface::set_num_u_knots
//       Access: Public
//  Description: Directly changes the number of knots in the U
//               direction.  This will either add zero-valued knots
//               onto the end, or truncate knot values from the end,
//               depending on whether the list is being increased or
//               decreased.  If possible, it is preferable to use the
//               setup() method instead of directly setting the number
//               of knots, as this may result in an invalid surface.
////////////////////////////////////////////////////////////////////
void EggNurbsSurface::
set_num_u_knots(int num) {
  if ((int)_u_knots.size() >= num) {
    // Truncate knot values at the end.
    _u_knots.erase(_u_knots.begin() + num, _u_knots.end());
  } else {
    // Append knot values to the end.
    _u_knots.reserve(num);
    for (int i = _u_knots.size(); i < num; i++) {
      _u_knots.push_back(0.0);
    }
  }
}

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsSurface::set_num_v_knots
//       Access: Public
//  Description: Directly changes the number of knots in the V
//               direction.  This will either add zero-valued knots
//               onto the end, or truncate knot values from the end,
//               depending on whether the list is being increased or
//               decreased.  If possible, it is preferable to use the
//               setup() method instead of directly setting the number
//               of knots, as this may result in an invalid surface.
////////////////////////////////////////////////////////////////////
void EggNurbsSurface::
set_num_v_knots(int num) {
  if ((int)_v_knots.size() >= num) {
    // Truncate knot values at the end.
    _v_knots.erase(_v_knots.begin() + num, _v_knots.end());
  } else {
    // Append knot values to the end.
    _v_knots.reserve(num);
    for (int i = _v_knots.size(); i < num; i++) {
      _v_knots.push_back(0.0);
    }
  }
}

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsSurface::is_valid
//       Access: Public
//  Description: Returns true if the NURBS parameters are all
//               internally consistent (e.g. it has the right number
//               of vertices to match its number of knots and order in
//               each dimension), or false otherwise.
////////////////////////////////////////////////////////////////////
bool EggNurbsSurface::
is_valid() const {
  if (_u_order < 1 || _u_order > 4 || _v_order < 1 || _v_order > 4) {
    // Invalid order.
    return false;
  }

  if (get_num_cvs() != (int)size()) {
    // Wrong number of CV's.
    return false;
  }

  // Do all the knot values monotonically increase?
  int i;
  for (i = 1; i < get_num_u_knots(); i++) {
    if (get_u_knot(i) < get_u_knot(i - 1)) {
      return false;
    }
  }
  for (i = 1; i < get_num_v_knots(); i++) {
    if (get_v_knot(i) < get_v_knot(i - 1)) {
      return false;
    }
  }

  // Everything's looking good!
  return true;
}

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsSurface::is_closed_u
//       Access: Public
//  Description: Returns true if the surface appears to be closed in
//               the U direction.  Since the Egg syntax does not
//               provide a means for explicit indication of closure,
//               this has to be guessed at by examining the surface
//               itself.
////////////////////////////////////////////////////////////////////
bool EggNurbsSurface::
is_closed_u() const {
  // Technically, the surface is closed if the CV's at the end are
  // repeated from the beginning.  We'll do a cheesy test for
  // expediency's sake: the surface is closed if the first n knots are
  // not repeated.  I think this will catch all the normal surfaces
  // we're likely to see.

  int i;
  for (i = 1; i < get_u_order(); i++) {
    if (get_u_knot(i) != get_u_knot(i-1)) {
      return true;
    }
  }
  return false;
}

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsSurface::is_closed_v
//       Access: Public
//  Description: Returns true if the surface appears to be closed in
//               the V direction.  Since the Egg syntax does not
//               provide a means for explicit indication of closure,
//               this has to be guessed at by examining the surface
//               itself.
////////////////////////////////////////////////////////////////////
bool EggNurbsSurface::
is_closed_v() const {
  int i;
  for (i = 1; i < get_v_order(); i++) {
    if (get_v_knot(i) != get_v_knot(i-1)) {
      return true;
    }
  }
  return false;
}

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsSurface::write
//       Access: Public, Virtual
//  Description: Writes the nurbsSurface to the indicated output stream in
//               Egg format.
////////////////////////////////////////////////////////////////////
void EggNurbsSurface::
write(ostream &out, int indent_level) const {
  write_header(out, indent_level, "<NurbsSurface>");

  Trims::const_iterator ti;
  for (ti = _trims.begin(); ti != _trims.end(); ++ti) {
    indent(out, indent_level + 2) << "<Trim> {\n";
    Loops::const_iterator li;
    for (li = (*ti).begin(); li != (*ti).end(); ++li) {
      indent(out, indent_level + 4) << "<Loop> {\n";
      Curves::const_iterator ci;
      for (ci = (*li).begin(); ci != (*li).end(); ++ci) {
        (*ci)->write(out, indent_level + 6);
      }
      indent(out, indent_level + 4) << "}\n";
    }
    indent(out, indent_level + 2) << "}\n";
  }

  if (get_u_subdiv() != 0) {
    indent(out, indent_level + 2)
      << "<Scalar> U-subdiv { " << get_u_subdiv() << " }\n";
  }
  if (get_v_subdiv() != 0) {
    indent(out, indent_level + 2)
      << "<Scalar> V-subdiv { " << get_v_subdiv() << " }\n";
  }
  indent(out, indent_level + 2)
    << "<Order> { " << get_u_order() << " " << get_v_order() << " }\n";
  indent(out, indent_level + 2)
    << "<U-Knots> {\n";
  write_long_list(out, indent_level+4, _u_knots.begin(), _u_knots.end(),
        "", "", 72);
  indent(out, indent_level + 2)
    << "}\n";
  indent(out, indent_level + 2)
    << "<V-Knots> {\n";
  write_long_list(out, indent_level+4, _v_knots.begin(), _v_knots.end(),
        "", "", 72);
  indent(out, indent_level + 2)
    << "}\n";

  write_body(out, indent_level+2);

  Curves::const_iterator ci;
  for (ci = _curves_on_surface.begin(); ci != _curves_on_surface.end(); ++ci) {
    (*ci)->write(out, indent_level + 2);
  }

  indent(out, indent_level) << "}\n";
}

////////////////////////////////////////////////////////////////////
//     Function: EggNurbsSurface::r_apply_texmats
//       Access: Protected, Virtual
//  Description: The recursive implementation of apply_texmats().
////////////////////////////////////////////////////////////////////
void EggNurbsSurface::
r_apply_texmats(EggTextureCollection &textures) {
  // A NURBS cannot safely apply texture matrices, so we leave it
  // alone.
}

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