LOD_ExternBufferEditor.h

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/*
 * ***** BEGIN GPL 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.
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 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 LICENSE BLOCK *****
 */

#ifndef NAN_INCLUDED_LOD_ExternBufferEditor_h
#define NAN_INCLUDED_LOD_ExternBufferEditor_h

#include "LOD_MeshPrimitives.h"
#include <vector>
#include "LOD_ManMesh2.h"
#include "../extern/LOD_decimation.h"


// This class syncs external vertex/face buffers 
// with the internal mesh representation during
// decimation.

class LOD_ExternBufferEditor 
{

public :

    static 
        LOD_ExternBufferEditor *
    New(
        LOD_Decimation_InfoPtr extern_info
    ){
        if (extern_info == NULL) return NULL;
        return new LOD_ExternBufferEditor(extern_info);
    }
    
    // update the external vertex buffer with vertices
    // from the mesh

        void
    CopyModifiedVerts(
        LOD_ManMesh2 & mesh,
        const std::vector<LOD_VertexInd> & mod_vertices
    ){
    
        std::vector<LOD_VertexInd>::const_iterator v_start = mod_vertices.begin();
        std::vector<LOD_VertexInd>::const_iterator v_end = mod_vertices.end();

        std::vector<LOD_Vertex> & mesh_verts = mesh.VertexSet();

        float * const extern_vertex_ptr = m_extern_info->vertex_buffer;

        for (; v_start != v_end; ++v_start) {
            float * mod_vert = extern_vertex_ptr + int(*v_start)*3;
            mesh_verts[*v_start].CopyPosition(mod_vert);
        }
    }           
        
    // update the external face buffer with faces from the mesh

        void
    CopyModifiedFaces(
        LOD_ManMesh2 & mesh,
        const std::vector<LOD_FaceInd> & mod_faces
    ){
    
        std::vector<LOD_FaceInd>::const_iterator f_start = mod_faces.begin();
        std::vector<LOD_FaceInd>::const_iterator f_end = mod_faces.end();

        std::vector<LOD_TriFace> &mesh_faces = mesh.FaceSet();

        int * const extern_face_ptr = m_extern_info->triangle_index_buffer;

        for (; f_start != f_end; ++f_start) {
            int *mod_face = extern_face_ptr + 3*int(*f_start);
            mesh_faces[*f_start].CopyVerts(mod_face);
        }
    }


    // Copy the last vertex over the vertex specified by
    // vi. Decrement the size of the vertex array   

        void
    CopyBackVertex(
        LOD_VertexInd vi
    ){

        float * const extern_vertex_ptr = m_extern_info->vertex_buffer;
        int * extern_vertex_num = &(m_extern_info->vertex_num);

        float * last_external_vert = extern_vertex_ptr + 3*((*extern_vertex_num) - 1);
        float * external_vert = extern_vertex_ptr + 3*int(vi);

        external_vert[0] = last_external_vert[0];
        external_vert[1] = last_external_vert[1];
        external_vert[2] = last_external_vert[2];

        *extern_vertex_num -=1;
    }

    // Copy the last face over the face specified by fi
    // Decrement the size of the face array

        void
    CopyBackFace(
        LOD_FaceInd fi
    ) {
        int * const extern_face_ptr = m_extern_info->triangle_index_buffer;
        int * extern_face_num = &(m_extern_info->face_num);
        
        int * last_external_face = extern_face_ptr + 3*((*extern_face_num) -1);
        int * external_face = extern_face_ptr + 3*int(fi);
        external_face[0] = last_external_face[0];
        external_face[1] = last_external_face[1];
        external_face[2] = last_external_face[2];

        *extern_face_num -=1;
    }   


private :
        
    LOD_ExternBufferEditor(
        LOD_Decimation_InfoPtr extern_info  
    ) :
        m_extern_info (extern_info)
    {
    }

    LOD_Decimation_InfoPtr const m_extern_info;

};

#endif