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BSP_CSGNCMeshSplitter.cpp

/**
 * $Id: BSP_CSGNCMeshSplitter.cpp,v 1.5 2005/10/28 20:18:56 intrr Exp $
 * ***** BEGIN GPL/BL DUAL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version. The Blender
 * Foundation also sells licenses for use in proprietary software under
 * the Blender License.  See http://www.blender.org/BL/ for information
 * about this.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL/BL DUAL LICENSE BLOCK *****
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "BSP_CSGNCMeshSplitter.h"

#include "BSP_CSGMesh.h"
#include "BSP_MeshFragment.h"
#include "BSP_CSGException.h"
#include "MT_MinMax.h"
#include "MT_assert.h"
#include <vector>

using namespace std;

BSP_CSGNCMeshSplitter::
00048 BSP_CSGNCMeshSplitter(
){
      //nothing to do
}

BSP_CSGNCMeshSplitter::
BSP_CSGNCMeshSplitter(
      const BSP_CSGNCMeshSplitter & other
){
      //nothing to do
};


      void
BSP_CSGNCMeshSplitter::
00063 Split(
      const MT_Plane3& plane,
      BSP_MeshFragment *frag,
      BSP_MeshFragment *in_frag,
      BSP_MeshFragment *out_frag,
      BSP_MeshFragment *on_frag,
      BSP_MeshFragment *spanning_frag
){
      // First classify the vertices and the polygons of the
      // incoming fragment.
      frag->Classify(plane,in_frag,out_frag,on_frag,m_spanning_faces,m_tagged_verts);

      SplitImp(*(frag->Mesh()),plane,m_spanning_faces,in_frag,out_frag,on_frag,m_tagged_verts);

      m_spanning_faces.clear();
      m_tagged_verts.clear();
}

/// Split the entire mesh with respect to the plane.

      void
BSP_CSGNCMeshSplitter::
00085 Split(
      BSP_CSGMesh & mesh,
      const MT_Plane3& plane,
      BSP_MeshFragment *in_frag,
      BSP_MeshFragment *out_frag,
      BSP_MeshFragment *on_frag,
      BSP_MeshFragment *spanning_frag
){
      BSP_MeshFragment::Classify(mesh, plane,in_frag,out_frag,on_frag,m_spanning_faces,m_tagged_verts);

      SplitImp(mesh,plane,m_spanning_faces,in_frag,out_frag,on_frag,m_tagged_verts);
      m_spanning_faces.clear();
      m_tagged_verts.clear();
}


BSP_CSGNCMeshSplitter::
~BSP_CSGNCMeshSplitter(
){
      //nothing to do
}

      void
BSP_CSGNCMeshSplitter::
SplitImp(
      BSP_CSGMesh & mesh,
      const MT_Plane3& plane,
      const std::vector<BSP_FaceInd> & spanning_faces,
      BSP_MeshFragment *in_frag,
      BSP_MeshFragment *out_frag,
      BSP_MeshFragment *on_frag,
      std::vector<BSP_VertexInd> & classified_verts
){

      // Just iterate through the spanning faces.
      // Identify the spanning 'edges' and create new vertices 
      // and split the polygons. We make no attempt to share 
      // vertices or preserve edge connectivity or maintain any
      // face properties etc.

      // Assumes you have already classified the vertices.
      // and generated a set of spanning faces.

      vector<BSP_MVertex> & vertex_set = mesh.VertexSet();
      vector<BSP_MFace> & face_set = mesh.FaceSet();

      vector<BSP_FaceInd>::const_iterator sface_end = m_spanning_faces.end();
      vector<BSP_FaceInd>::const_iterator sface_it = m_spanning_faces.begin();

      for (;sface_it != sface_end; ++sface_it) {
            BSP_FaceInd f_in,f_out;
            SplitPolygon(plane,mesh,*sface_it,f_in,f_out);
            
            // Use the open tag to store the original index of the face.
            // This is originally -1.

            if (face_set[*sface_it].OpenTag() == -1) {
                  face_set[f_in].SetOpenTag(*sface_it);
                  face_set[f_out].SetOpenTag(*sface_it);
            } else {
                  face_set[f_in].SetOpenTag(face_set[*sface_it].OpenTag());
                  face_set[f_out].SetOpenTag(face_set[*sface_it].OpenTag());
            }

            in_frag->FaceSet().push_back(f_in);
            out_frag->FaceSet().push_back(f_out);
      }
      
      vector<BSP_VertexInd>::const_iterator v_end = classified_verts.end();
      vector<BSP_VertexInd>::const_iterator v_it = classified_verts.begin();

      for (; v_it != v_end; ++v_it) {
            vertex_set[*v_it].SetOpenTag(e_unclassified);
      }
}

      void
BSP_CSGNCMeshSplitter::
SplitPolygon(
      const MT_Plane3& plane,
      BSP_CSGMesh & mesh,
      BSP_FaceInd fi,
      BSP_FaceInd &fin,
      BSP_FaceInd &fout
){

      vector<BSP_MVertex> & vertex_set = mesh.VertexSet();
      vector<BSP_MFace> & face_set = mesh.FaceSet();

      BSP_FaceInd new_fi = face_set.size();
      face_set.push_back(BSP_MFace());

      BSP_MFace & face = face_set[fi];
      BSP_MFace &new_face = face_set[new_fi];

      vector<BSP_VertexInd>::const_iterator f_verts_it = face.m_verts.begin();
      vector<BSP_VertexInd>::const_iterator f_verts_end = face.m_verts.end();
      
      MT_Point3 ptA = vertex_set[face.m_verts.back()].m_pos;
      BSP_Classification prev_class = BSP_Classification(vertex_set[face.m_verts.back()].OpenTag());

      for (; f_verts_it != f_verts_end;++f_verts_it) {

            BSP_Classification v_class = BSP_Classification(vertex_set[*f_verts_it].OpenTag());

            if (v_class == e_classified_on) {
                  m_in_loop.push_back(*f_verts_it);
                  m_out_loop.push_back(*f_verts_it);
                  prev_class = e_classified_on;
                  continue;
            } else 
            if (v_class == e_classified_in) {
                  m_in_loop.push_back(*f_verts_it);
            } else 
            if (v_class == e_classified_out) {
                  m_out_loop.push_back(*f_verts_it);
            }

            if ((prev_class != e_classified_on) &&
                  (prev_class != v_class)) {
                  // spanning edge

                  const MT_Point3 & ptB = vertex_set[*f_verts_it].m_pos;

                  // compute the intersection point of plane and ptA->ptB
                  MT_Vector3 v = ptB - ptA;
                  MT_Scalar sideA = plane.signedDistance(ptA);

                  MT_Scalar epsilon = -sideA/plane.Normal().dot(v);
                  MT_Point3 new_p = ptA + (v * epsilon);

                  BSP_VertexInd new_vi(vertex_set.size());
                  vertex_set.push_back(BSP_MVertex(new_p));

                  m_in_loop.push_back(new_vi);
                  m_out_loop.push_back(new_vi);
            }
            
            ptA = vertex_set[*f_verts_it].m_pos;
            prev_class = v_class;
      }

      // Ok should have 2 loops 1 representing the in_loop and
      // 1 for the out_loop
      
      new_face.m_verts = m_out_loop;
      face.m_verts = m_in_loop;

      new_face.m_plane = face.m_plane;

      // we don't bother maintaining any of the other 
      // properties.
      
      fin = fi;
      fout = new_fi;
      
      m_in_loop.clear();
      m_out_loop.clear();
};



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