vcglib: picking.h Source File

00001 #pragma once    
00002 /****************************************************************************
00003 * VCGLib                                                            o o     *
00004 * Visual and Computer Graphics Library                            o     o   *
00005 *                                                                _   O  _   *
00006 * Copyright(C) 2004                                                \/)\/    *
00007 * Visual Computing Lab                                            /\/|      *
00008 * ISTI - Italian National Research Council                           |      *
00009 *                                                                    \      *
00010 * All rights reserved.                                                      *
00011 *                                                                           *
00012 * This program is free software; you can redistribute it and/or modify      *   
00013 * it under the terms of the GNU General Public License as published by      *
00014 * the Free Software Foundation; either version 2 of the License, or         *
00015 * (at your option) any later version.                                       *
00016 *                                                                           *
00017 * This program is distributed in the hope that it will be useful,           *
00018 * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
00019 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the             *
00020 * GNU General Public License (http://www.gnu.org/licenses/gpl.txt)          *
00021 * for more details.                                                         *
00022 *                                                                           *
00023 ****************************************************************************/
00024 /****************************************************************************
00025 This file contains two function providing the standard way to do picking using opendgl:
00026 - using the SELECT mode (first function)
00027 - using the depth buffer and gluUnproject (second function)
00028 
00029   History
00030 $Log: not supported by cvs2svn $
00031 Revision 1.5  2007/05/21 13:22:40  cignoni
00032 Corrected gcc compiling issues
00033 
00034 Revision 1.4  2006/10/27 08:55:15  fiorin
00035 Added type cast (in order to remove warnings)
00036 
00037 Revision 1.3  2006/02/28 13:25:48  ponchio
00038 for(ii... -> for(int ii
00039 
00040 Revision 1.2  2006/02/13 13:06:34  cignoni
00041 Removed glut. Added ifdef guards and namespace.
00042 Added bool return value to the pick function
00043 
00044 Revision 1.1  2005/12/03 09:36:28  ganovelli
00045 *** empty log message ***
00046 
00047 ****************************************************************************/
00048 
00049 #ifndef WRAP_GL_PICKING_H
00050 #define WRAP_GL_PICKING_H
00051 
00052 #include <algorithm>
00053 namespace vcg
00054 {
00055 
00056 template <class TO_PICK_CONT_TYPE>
00057 int Pick(       const int & x, const int &y, 
00058                                         TO_PICK_CONT_TYPE &m, 
00059                                         std::vector<typename TO_PICK_CONT_TYPE::value_type*> &result, 
00060                                         void (draw_func)(typename TO_PICK_CONT_TYPE::value_type &),
00061                                         int width=4, 
00062                                         int height=4)
00063         {
00064                 result.clear();
00065                 long hits;      
00066                 int sz = int(m.size())*5;
00067                 GLuint *selectBuf =new GLuint[sz];
00068                 glSelectBuffer(sz, selectBuf);
00069                 glRenderMode(GL_SELECT);
00070                 glInitNames();
00071 
00072                 /* Because LoadName() won't work with no names on the stack */
00073                 glPushName(-1);
00074                 double mp[16];
00075 
00076                 GLint viewport[4];
00077                 glGetIntegerv(GL_VIEWPORT,viewport);
00078                 glPushAttrib(GL_TRANSFORM_BIT);
00079                 glMatrixMode(GL_PROJECTION);
00080                 glGetDoublev(GL_PROJECTION_MATRIX ,mp);
00081                 glPushMatrix();
00082                 glLoadIdentity();
00083                 //gluPickMatrix(x, viewport[3]-y, 4, 4, viewport);
00084                 gluPickMatrix(x, y, width, height, viewport);
00085                 glMultMatrixd(mp);
00086 
00087                 glMatrixMode(GL_MODELVIEW);
00088                 glPushMatrix();
00089                 int cnt=0; 
00090                 typename TO_PICK_CONT_TYPE::iterator  ei;
00091                 for(ei=m.begin();ei!=m.end();++ei)
00092                 {
00093 
00094                                 glLoadName(cnt);
00095                                 draw_func(*ei);
00096                                 cnt++;
00097                 }
00098 
00099                 glPopMatrix();
00100                 glMatrixMode(GL_PROJECTION);
00101                 glPopMatrix();
00102                 glMatrixMode(GL_MODELVIEW);
00103                 hits = glRenderMode(GL_RENDER);
00104                 
00105                 if (hits <= 0)     return 0;
00106                 std::vector< std::pair<double,unsigned int> > H;
00107                 for(int ii=0;ii<hits;ii++){
00108                         H.push_back( std::pair<double,unsigned int>(selectBuf[ii*4+1]/4294967295.0,selectBuf[ii*4+3]));
00109                 }
00110                 std::sort(H.begin(),H.end());
00111 
00112                 result.resize(H.size());
00113                 for(int ii=0;ii<hits;ii++){
00114                         typename TO_PICK_CONT_TYPE::iterator ei=m.begin();
00115                         std::advance(ei ,H[ii].second);
00116                         result[ii]=&*ei;
00117                 }
00118                 glPopAttrib();
00119                 delete [] selectBuf;
00120                 return int(result.size());
00121         }
00122 
00123 // 10/2/06 Slightly changed the interface. 
00124 // Return value is used to determine if the picked point was against the far plane 
00125 // (and therefore nothing was picked)
00126 template <class PointType>
00127 bool Pick(const int & x, const int &y, PointType &pp){
00128         double res[3];
00129         GLdouble mm[16],pm[16]; GLint vp[4];
00130         glGetDoublev(GL_MODELVIEW_MATRIX,mm);
00131         glGetDoublev(GL_PROJECTION_MATRIX,pm);
00132         glGetIntegerv(GL_VIEWPORT,vp);
00133         
00134         float   pix;
00135         glReadPixels(x,y,1,1,GL_DEPTH_COMPONENT,GL_FLOAT,&pix);
00136   GLfloat depthrange[2]={0,0};
00137   glGetFloatv(GL_DEPTH_RANGE,depthrange);
00138   if(pix==depthrange[1]) return false;
00139         gluUnProject(x,y,pix,mm,pm,vp,&res[0],&res[1],&res[2]);
00140         pp=PointType (res[0],res[1],res[2]);
00141   return true;
00142         }
00143 
00144 } // end namespace
00145 
00146 #endif