VisibilityOptimizer.cpp

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/*
 This file is part of the VRender library.
 Copyright (C) 2005 Cyril Soler (Cyril.Soler@imag.fr)
 Version 1.0.0, released on June 27, 2005.

 http://artis.imag.fr/Members/Cyril.Soler/VRender

 VRender 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.

 VRender 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 VRender; if not, write to the Free Software Foundation, Inc.,
 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
*/

/****************************************************************************

 Copyright (C) 2002-2013 Gilles Debunne. All rights reserved.

 This file is part of the QGLViewer library version 2.4.0.

 http://www.libqglviewer.com - contact@libqglviewer.com

 This file may be used under the terms of the GNU General Public License 
 versions 2.0 or 3.0 as published by the Free Software Foundation and
 appearing in the LICENSE file included in the packaging of this file.
 In addition, as a special exception, Gilles Debunne gives you certain 
 additional rights, described in the file GPL_EXCEPTION in this package.

 libQGLViewer uses dual licensing. Commercial/proprietary software must
 purchase a libQGLViewer Commercial License.

 This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

*****************************************************************************/

#include <vector>
#include "VRender.h"
#include "Optimizer.h"
#include "Primitive.h"
#include "gpc.h"
#include "math.h"

using namespace vrender ;
using namespace std ;

#ifdef A_FAIRE
void VisibilityOptimizer::optimize(vector<PtrPrimitive>& primitives,float& percentage_finished,string& message)
#else
void VisibilityOptimizer::optimize(vector<PtrPrimitive>& primitives,VRenderParams& vparams)
#endif
{
#ifdef DEBUG_VO
        cout << "Optimizing visibility." << endl ;
#endif
        unsigned int N = primitives.size()/200 + 1 ;

#ifdef DEBUG_EPSRENDER__SHOW1
//      cout << "Showing viewer." << endl ;
//      myViewer viewer ;
//      viewer.show();
        double minx =  FLT_MAX ;
        double miny =  FLT_MAX ;
        double maxx = -FLT_MAX ;
        double maxy = -FLT_MAX ;
        for(unsigned int i=0;i<primitives.size();++i)
                for(int j=0;j<primitives[i]->nbVertices();++j)
                {
                        if(maxx < primitives[i]->vertex(j).x()) maxx = primitives[i]->vertex(j).x() ;
                        if(maxy < primitives[i]->vertex(j).y()) maxy = primitives[i]->vertex(j).y() ;
                        if(minx > primitives[i]->vertex(j).x()) minx = primitives[i]->vertex(j).x() ;
                        if(miny > primitives[i]->vertex(j).y()) miny = primitives[i]->vertex(j).y() ;
                }

        glMatrixMode(GL_PROJECTION) ;
        glLoadIdentity() ;
        glOrtho(minx,maxx,miny,maxy,-1,1) ;
        glMatrixMode(GL_MODELVIEW) ;
        glLoadIdentity() ;

        cout << "Window set to " << minx << " " << maxx << " " << miny << " " << maxy << endl ;
        glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT) ;
        glLineWidth(3.0) ;
#endif

        int nb_culled = 0 ;

        // Ca serait pas mal mieux avec une interface c++...

        gpc_polygon cumulated_union ;
        cumulated_union.num_contours = 0 ;
        cumulated_union.hole = NULL ;
        cumulated_union.contour = NULL ;
        int nboptimised = 0 ;

        for(int pindex = (int)(primitives.size()) - 1; pindex >= 0;--pindex,++nboptimised)
                if(primitives[pindex] != NULL)
                {
#ifdef A_FAIRE
                        percentage_finished = pindex / (float)primitives.size() ;
#endif

                        if(primitives[pindex]->nbVertices() > 1)
                        {
#ifdef DEBUG_VO
                                if(pindex%50==0)
                                {
                                        char buff[500] ;
                                        sprintf(buff,"Left: % 6ld - Culled: % 6ld", (long)pindex,(long)nb_culled) ;
                                        fprintf(stdout,buff);

                                        for(unsigned int j=0;j<strlen(buff);++j)
                                                fprintf(stdout,"\b") ;

                                        fflush(stdout) ;
                                }
#endif

                                try
                                {
                                        PtrPrimitive p(primitives[pindex]) ;
                                        gpc_polygon difference ;
                                        gpc_polygon new_poly ;
                                        gpc_polygon new_poly_reduced ;
                                        new_poly.num_contours = 0 ;
                                        new_poly.hole = NULL ;
                                        new_poly.contour = NULL ;
                                        new_poly_reduced.num_contours = 0 ;
                                        new_poly_reduced.hole = NULL ;
                                        new_poly_reduced.contour = NULL ;

                                        // 1 - creates a gpc_polygon corresponding to the current primitive

                                        gpc_vertex_list *new_poly_verts = new gpc_vertex_list ;
                                        gpc_vertex_list *new_poly_reduced_verts = new gpc_vertex_list ;

                                        double mx = 0.0 ;
                                        double my = 0.0 ;

                                        if(p->nbVertices() == 2)
                                        {
                                                new_poly_verts->num_vertices = 4 ;
                                                new_poly_verts->vertex = new gpc_vertex[4] ;
                                                new_poly_reduced_verts->num_vertices = 4 ;
                                                new_poly_reduced_verts->vertex = new gpc_vertex[4] ;

                                                double deps = 0.001 ;
                                                double du = p->vertex(1).y()-p->vertex(0).y() ;
                                                double dv = p->vertex(1).x()-p->vertex(0).x() ;
                                                double n = sqrt(du*du+dv*dv) ;
                                                du *= deps/n ;
                                                dv *= deps/n ;
                                                new_poly_verts->vertex[0].x = p->vertex(0).x() + du ;
                                                new_poly_verts->vertex[0].y = p->vertex(0).y() + dv ;
                                                new_poly_verts->vertex[1].x = p->vertex(1).x() + du ;
                                                new_poly_verts->vertex[1].y = p->vertex(1).y() + dv ;
                                                new_poly_verts->vertex[2].x = p->vertex(1).x() - du ;
                                                new_poly_verts->vertex[2].y = p->vertex(1).y() - dv ;
                                                new_poly_verts->vertex[3].x = p->vertex(0).x() - du ;
                                                new_poly_verts->vertex[3].y = p->vertex(0).y() - dv ;

                                                new_poly_reduced_verts->vertex[0].x = p->vertex(0).x() + du ;
                                                new_poly_reduced_verts->vertex[0].y = p->vertex(0).y() + dv ;
                                                new_poly_reduced_verts->vertex[1].x = p->vertex(1).x() + du ;
                                                new_poly_reduced_verts->vertex[1].y = p->vertex(1).y() + dv ;
                                                new_poly_reduced_verts->vertex[2].x = p->vertex(1).x() - du ;
                                                new_poly_reduced_verts->vertex[2].y = p->vertex(1).y() - dv ;
                                                new_poly_reduced_verts->vertex[3].x = p->vertex(0).x() - du ;
                                                new_poly_reduced_verts->vertex[3].y = p->vertex(0).y() - dv ;
                                        }
                                        else
                                        {
                                                new_poly_verts->num_vertices = p->nbVertices() ;
                                                new_poly_verts->vertex = new gpc_vertex[p->nbVertices()] ;

                                                for(unsigned int i=0;i<p->nbVertices();++i)
                                                {
                                                        new_poly_verts->vertex[i].x = p->vertex(i).x() ;
                                                        new_poly_verts->vertex[i].y = p->vertex(i).y() ;
                                                        mx += p->vertex(i).x() ;
                                                        my += p->vertex(i).y() ;
                                                }
                                                mx /= p->nbVertices() ;
                                                my /= p->nbVertices() ;

                                                new_poly_reduced_verts->num_vertices = p->nbVertices() ;
                                                new_poly_reduced_verts->vertex = new gpc_vertex[p->nbVertices()] ;

                                                for(unsigned int j=0;j<p->nbVertices();++j)
                                                {
                                                        new_poly_reduced_verts->vertex[j].x = mx + (p->vertex(j).x() - mx)*0.999 ;
                                                        new_poly_reduced_verts->vertex[j].y = my + (p->vertex(j).y() - my)*0.999 ;
                                                }
                                        }
                                        gpc_add_contour(&new_poly,new_poly_verts,false) ;
                                        gpc_add_contour(&new_poly_reduced,new_poly_reduced_verts,false) ;

                                        // 2 - computes the difference between this polygon, and the union of the
                                        //      preceeding ones.

                                        gpc_polygon_clip(GPC_DIFF,&new_poly_reduced,&cumulated_union,&difference) ;

                                        // 3 - checks the difference. If void, the primitive is not visible: skip it
                                        //      and go to next primitive.

                                        if(difference.num_contours == 0)
                                        {
                                                ++nb_culled ;
                                                delete p ;
                                                primitives[pindex] = NULL ;
                                                continue ;
                                        }

                                        // 4 - The primitive is visible. Let's add it to the cumulated union of
                                        //      primitives.

                                        if(p->nbVertices() > 2)
                                        {
                                                gpc_polygon cumulated_union_tmp ;
                                                cumulated_union_tmp.num_contours = 0 ;
                                                cumulated_union_tmp.hole = NULL ;
                                                cumulated_union_tmp.contour = NULL ;

                                                gpc_polygon_clip(GPC_UNION,&new_poly,&cumulated_union,&cumulated_union_tmp) ;

                                                gpc_free_polygon(&cumulated_union) ;
                                                cumulated_union = cumulated_union_tmp ;
                                        }

                                        gpc_free_polygon(&new_poly) ;
                                        gpc_free_polygon(&new_poly_reduced) ;
                                        gpc_free_polygon(&difference) ;
#ifdef DEBUG_EPSRENDER__SHOW1
                                        glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT) ;

                                        glColor3f(1.0,0.0,0.0) ;

                                        for(int i=0;i<cumulated_union.num_contours;++i)
                                        {
                                                glBegin(GL_LINE_LOOP) ;
                                                for(int j=0;j<cumulated_union.contour[i].num_vertices;++j)
                                                        glVertex2f(cumulated_union.contour[i].vertex[j].x,cumulated_union.contour[i].vertex[j].y) ;
                                                glEnd() ;
                                        }

                                        glFlush() ;
                                        glXSwapBuffers(glXGetCurrentDisplay(),glXGetCurrentDrawable()) ;
#endif
                                }
                                catch(exception& )
                                {
                                        ; // std::cout << "Could not treat primitive " << pindex << ": internal gpc error." << endl ;
                                }
                        }

                        if(nboptimised%N==0)
                                vparams.progress(nboptimised/(float)primitives.size(), QGLViewer::tr("Visibility optimization")) ;
                }

#ifdef DEBUG_VO
        cout << nb_culled << " primitives culled over " << primitives.size() << "." << endl ;
#endif

        gpc_free_polygon(&cumulated_union) ;
}