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wrap/gl/picking.h

@@ -0,0 +1,116 @@
+#pragma once	
+/****************************************************************************
+* VCGLib                                                            o o     *
+* Visual and Computer Graphics Library                            o     o   *
+*                                                                _   O  _   *
+* Copyright(C) 2004                                                \/)\/    *
+* Visual Computing Lab                                            /\/|      *
+* ISTI - Italian National Research Council                           |      *
+*                                                                    \      *
+* All rights reserved.                                                      *
+*                                                                           *
+* 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 (http://www.gnu.org/licenses/gpl.txt)          *
+* for more details.                                                         *
+*                                                                           *
+****************************************************************************/
+/****************************************************************************
+This file contains two function providing the standard way to do picking using opendgl:
+- using the SELECT mode (first function)
+- using the depth buffer and gluUnproject (second function)
+
+  History
+$Log: not supported by cvs2svn $
+****************************************************************************/
+
+
+#include <algorithm>
+#include <GL/glut.h>
+
+template <class TO_PICK_CONT_TYPE>
+int Pick(	const int & x, const int &y, 
+					TO_PICK_CONT_TYPE &m, 
+					std::vector<typename TO_PICK_CONT_TYPE::value_type*> &result, 
+					void (draw_func)(typename TO_PICK_CONT_TYPE::value_type &),
+					int width=4, 
+					int height=4)
+	{
+		result.clear();
+		long hits;	
+		int sz=m.size()*5;
+		unsigned int *selectBuf =new unsigned int[sz];
+		glSelectBuffer(sz, selectBuf);
+		glRenderMode(GL_SELECT);
+		glInitNames();
+
+		/* Because LoadName() won't work with no names on the stack */
+		glPushName(-1);
+		double mp[16];
+
+		int viewport[4];
+		glGetIntegerv(GL_VIEWPORT,viewport);
+		glMatrixMode(GL_PROJECTION);
+		glGetDoublev(GL_PROJECTION_MATRIX ,mp);
+		glPushMatrix();
+		glLoadIdentity();
+		//gluPickMatrix(x, viewport[3]-y, 4, 4, viewport);
+		gluPickMatrix(x, y, width, height, viewport);
+		glMultMatrixd(mp);
+
+		glMatrixMode(GL_MODELVIEW);
+		glPushMatrix();
+		int cnt=0; 
+		typename TO_PICK_CONT_TYPE::iterator  ei;
+		for(ei=m.begin();ei!=m.end();++ei)
+		{
+
+				glLoadName(cnt);
+				draw_func(*ei);
+				cnt++;
+		}
+
+		glPopMatrix();
+		glMatrixMode(GL_PROJECTION);
+		glPopMatrix();
+		glMatrixMode(GL_MODELVIEW);
+		hits = glRenderMode(GL_RENDER);
+		
+		if (hits <= 0)     return 0;
+		std::vector< std::pair<double,unsigned int> > H;
+		for(int ii=0;ii<hits;ii++){
+			H.push_back( std::pair<double,unsigned int>(selectBuf[ii*4+1]/4294967295.0,selectBuf[ii*4+3]));
+		}
+		std::sort(H.begin(),H.end());
+
+		result.resize(H.size());
+		for(ii=0;ii<hits;ii++){
+			typename TO_PICK_CONT_TYPE::iterator ei=m.begin();
+			advance(ei ,H[ii].second);
+			result[ii]=&*ei;
+		}
+
+		delete [] selectBuf;
+		return result.size();
+	}
+
+template <class PointType>
+PointType Pick(const int & x, const int &y){
+	double res[3];
+	GLdouble mm[16],pm[16]; GLint vp[4];
+	glGetDoublev(GL_MODELVIEW_MATRIX,mm);
+	glGetDoublev(GL_PROJECTION_MATRIX,pm);
+	glGetIntegerv(GL_VIEWPORT,vp);
+	
+	float   pix;
+	glReadPixels(x,y,1,1,GL_DEPTH_COMPONENT,GL_FLOAT,&pix);
+	gluUnProject(x,y,pix,mm,pm,vp,&res[0],&res[1],&res[2]);
+	return PointType (res[0],res[1],res[2]);
+	}
+