LOD_QSDecimator.cpp

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/*
 * $Id: LOD_QSDecimator.cpp 35147 2011-02-25 10:47:28Z jesterking $
 * ***** 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 *****
 */

#include "LOD_QSDecimator.h"

#include "LOD_ExternBufferEditor.h"

using namespace std;

        LOD_QSDecimator *
LOD_QSDecimator::
New(
        LOD_ManMesh2 &mesh,
        LOD_ExternNormalEditor &face_editor,
        LOD_ExternBufferEditor &extern_editor
){

        MEM_SmartPtr<LOD_QSDecimator> output 
                = new LOD_QSDecimator(mesh,face_editor,extern_editor);

        MEM_SmartPtr<LOD_EdgeCollapser > collapser(LOD_EdgeCollapser::New());
        MEM_SmartPtr<LOD_QuadricEditor> q_editor(LOD_QuadricEditor::New(mesh));

        if (
                output == NULL ||
                collapser == NULL ||
                q_editor == NULL 
        ) {
                return NULL;
        }
        output->m_collapser = collapser.Release();
        output->m_quadric_editor = q_editor.Release();
        return output.Release();
}       



        bool
LOD_QSDecimator::
Arm(
){
        MT_assert(!m_is_armed);
        bool heap_result = BuildHeap();
        if (!heap_result) {
                return false;
        }
        m_is_armed = true;
        return true;
}
        
        bool
LOD_QSDecimator::
Step(
){
        return CollapseEdge();
}


LOD_QSDecimator::
LOD_QSDecimator(
        LOD_ManMesh2 &mesh,
        LOD_ExternNormalEditor &face_editor,
        LOD_ExternBufferEditor &extern_editor
) :
        m_is_armed (false),
        m_mesh(mesh),
        m_face_editor(face_editor),
        m_extern_editor(extern_editor)
{       
        m_deg_edges.reserve(32);
        m_deg_faces.reserve(32);
        m_deg_vertices.reserve(32);
        m_update_faces.reserve(32);
        m_new_edges.reserve(32);
        m_update_vertices.reserve(32);
};

        bool
LOD_QSDecimator::
CollapseEdge(
){
        
        // find an edge to collapse
        
        // FIXME force an edge collapse
        // or return false

        std::vector<LOD_Edge> & edges = m_mesh.EdgeSet();
        std::vector<LOD_Vertex> & verts = m_mesh.VertexSet();
        std::vector<LOD_Quadric> & quadrics = m_quadric_editor->Quadrics();
        int size = edges.size();

        if (size == 0) return false;

        const int heap_top = m_heap->Top();

        if (heap_top == -1 || edges[heap_top].HeapKey() <= -MT_INFINITY) {
                return false;
        }
        
        // compute the target position
        MT_Vector3 new_vertex = m_quadric_editor->TargetVertex(edges[heap_top]);
        LOD_Quadric & q0 = quadrics[edges[heap_top].m_verts[0]];
        LOD_Quadric & q1 = quadrics[edges[heap_top].m_verts[1]];

        LOD_Vertex &v0 = verts[edges[heap_top].m_verts[0]];
        LOD_Vertex &v1 = verts[edges[heap_top].m_verts[1]];

        LOD_Quadric sum = q0;
        sum += q1;


        if (m_collapser->CollapseEdge(
                        heap_top,
                        m_mesh,
                        m_deg_edges,
                        m_deg_faces,
                        m_deg_vertices,
                        m_new_edges,
                        m_update_faces,
                        m_update_vertices
        )) {

                // assign new vertex position

                 v0.pos = new_vertex;
                 v1.pos = new_vertex;

                // sum the quadrics of v0 and v1
                q0 = sum;
                q1 = sum;

                // ok update the primitive properties

                m_face_editor.Update(m_update_faces);   
                m_face_editor.UpdateVertexNormals(m_update_vertices);

                // update the external vertex buffer 
                m_extern_editor.CopyModifiedVerts(m_mesh,m_update_vertices);

                // update the external face buffer
                m_extern_editor.CopyModifiedFaces(m_mesh,m_update_faces);

                // update the edge heap
                UpdateHeap(m_deg_edges,m_new_edges);

                m_quadric_editor->Remove(m_deg_vertices);
                m_face_editor.Remove(m_deg_faces);
                m_face_editor.RemoveVertexNormals(m_deg_vertices);              
                                
                // delete the primitives

                DeletePrimitives(m_deg_edges,m_deg_faces,m_deg_vertices);

        } else {
                // the edge could not be collapsed at the moment - so
                // we adjust it's priority and add it back to the heap.
                m_heap->Remove(&edges[0],0);
                edges[heap_top].HeapKey() = - MT_INFINITY;
                m_heap->Insert(&edges[0],heap_top);
        }

        //clear all the temporary buffers

        m_deg_faces.clear();
        m_deg_edges.clear();
        m_deg_vertices.clear();
        
        m_update_faces.clear();
        m_update_vertices.clear();
        m_new_edges.clear();

        return true;

}       

        void
LOD_QSDecimator::
DeletePrimitives(
        const vector<LOD_EdgeInd> & degenerate_edges,
        const vector<LOD_FaceInd> & degenerate_faces,
        const vector<LOD_VertexInd> & degenerate_vertices
) {

        // assumes that the 3 vectors are sorted in descending order.

        // Delete Degnerate primitives


        // delete the old edges - we have to be very careful here
        // mesh.delete() swaps edges to be deleted with the last edge in 
        // the edge buffer. However the next edge to be deleted may have
        // been the last edge in the buffer!

        // One way to solve this is to sort degenerate_edges in descending order.
        // And then delete them in that order.
        
        // it is also vital that degenerate_edges contains no duplicates

        vector<LOD_EdgeInd>::const_iterator edge_it = degenerate_edges.begin();
        vector<LOD_EdgeInd>::const_iterator edge_end = degenerate_edges.end();

        for (; edge_it != edge_end; ++edge_it) {
                m_mesh.DeleteEdge(*edge_it,m_heap);
        }



        vector<LOD_FaceInd>::const_iterator face_it = degenerate_faces.begin();
        vector<LOD_FaceInd>::const_iterator face_end = degenerate_faces.end();
        
        for (;face_it != face_end; ++face_it) {
                m_mesh.DeleteFace(m_extern_editor,*face_it);
        }

        vector<LOD_VertexInd>::const_iterator vertex_it = degenerate_vertices.begin();
        vector<LOD_VertexInd>::const_iterator vertex_end = degenerate_vertices.end();
        
        for (;vertex_it != vertex_end; ++vertex_it) {
                m_mesh.DeleteVertex(m_extern_editor,*vertex_it);
        }
}


        bool
LOD_QSDecimator::
BuildHeap(
){
        // build the quadrics 

        if (m_quadric_editor->BuildQuadrics(m_face_editor,true) == false) return false;


        m_heap = CTR_UHeap<LOD_Edge>::New();
        // load in edge pointers to the heap

        std::vector<LOD_Edge> & edge_set= m_mesh.EdgeSet();
        std::vector<LOD_Edge>::const_iterator edge_end = edge_set.end();
        std::vector<LOD_Edge>::iterator edge_start = edge_set.begin();

        std::vector<int> & heap_vector = m_heap->HeapVector();

        for (unsigned int i = 0; i < edge_set.size(); ++i) {
                edge_set[i].HeapPos() = i;
                heap_vector.push_back(i);
        }
        
        m_heap->MakeHeap(&edge_set[0]);

        return true;
}

        void
LOD_QSDecimator::
UpdateHeap(
        std::vector<LOD_EdgeInd> &deg_edges,
        std::vector<LOD_EdgeInd> &new_edges
){
        // first of all compute values for the new edges 
        // and bung them on the heap.

        std::vector<LOD_Edge>  & edge_set= m_mesh.EdgeSet();

        std::vector<LOD_EdgeInd>::const_iterator edge_it = new_edges.begin();
        std::vector<LOD_EdgeInd>::const_iterator end_it = new_edges.end();


        // insert all the new edges             

        // compute edge costs ffor the new edges

        m_quadric_editor->ComputeEdgeCosts(new_edges);

        // inser the new elements into the heap

        for (; edge_it != end_it; ++edge_it) {          
                m_heap->Insert(&edge_set[0],*edge_it);
        }


        // remove all the old values from the heap

        edge_it = deg_edges.begin();
        end_it = deg_edges.end();

        for (; edge_it != end_it; ++edge_it) {
                LOD_Edge &e = edge_set[*edge_it];
                m_heap->Remove(&edge_set[0],e.HeapPos());

                e.HeapPos() = -1;

        }
}