CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

Can you post a complete minimal example showing the problem?

S.

Yue Biek wrote:
> Hello,
> This time I used the Lazy_exact type for my Point class,but I met 
> problems once more,the problems are discribed as follows.
> The Point Class  in my code is:
> Class MyPoint
> { 
> private:
> MP_FT pos[2]; //used to store x and y coordinate 
> public:
>        MP_FT & x() {return *pos;}
> }
>
> I used the following code to show my problem. in main function:
> int main()
> {
>         Point p(0.1, 0.2);
> MP_FT x = p.x();
> std::cout << p.x() << std::endl;
> }
>
> but the code show faults:the wrong place is in Interval_nt.h and the 
> code is:
> bool is_point() const
>  {
>     return sup() == inf();
>  }
> Thank you!
>
> 2011/5/13 Efraim Fogel 
> <
>  
> <mailto:>>
>
>     You need to use exact-predicate and exact-construction kernel.
>     When you attach code, attach it in a way that it can be compiled and
>     executed, and perhaps even read by a human being.
>
>
>     Yue Biek wrote:
>
>         My OS is win7(32bit) and environment is  VS2008,When I used the
>         MinKowski_2 in CGAL_3.8, I found the Union operation of two
>         Boundarys is something wrong.
>
>         the function are usd in Minkowski_sum_decomp_2.h
>         *The exact line is :*
>         sum_holes = unite(boundary_segments.begin(),
>         boundary_segments.end(),sum_bound, sum_holes);
>
>         My target is to morph between two non-convex but simple polygons.
>         At first,when I morph between a triangle and a rectangle,the
>         "unite" operation is right.and the morph process is right.
>         However,when the input are two non-convex
>         polygons(PandQ.dat),though the MinKowski sums of the two
>         polygons can be calcuated, the "unite" operation are something
>         wrong. when the input are two non convex polygons, the "unite"
>         operation are right the in the first time,but in the second time
>         ,it fails.
>
>         Part of source code are here,Polygon P and Polygon Q are defined
>         before hand,and they are all non-convex and simple(PandQ.dat).
>
>             glClear(GL_COLOR_BUFFER_BIT);
>         float delt=0.11;
>         while(true)
>         {
>         for(float t=0.1;t<=0.9;t+=delt)
>         {
>         glClear(GL_COLOR_BUFFER_BIT);
>         Polygon s_temp;
>         Polygon t_temp;
>
>         for(size_t i=0;i!=P.size();i++)
>         {
>         double temp_x=P[i].x()*(1-t);
>         double temp_y=P[i].y()*(1-t);
>         Point temp_p(temp_x,temp_y);
>         s_temp.push_back(temp_p);
>         }
>
>         for(size_t i=0;i!=Q.size();i++)
>         {
>         double temp_x=Q[i].x()*t;
>         double temp_y=Q[i].y()*t;
>         Point temp_p(temp_x,temp_y);
>         t_temp.push_back(temp_p);
>         }
>
>         Polygon_with_holes sum=minkowski_sum_2(s_temp,t_temp,ssab_decomp);
>                                                                      
>          std::cout << "P = "; print_polygon (s_temp);
>         std::cout << "Q = "; print_polygon (t_temp);
>         std::cout << "P (+) Q = ";print_polygon(sum.outer_boundary());
>
>         if(!sum.is_unbounded())
>         {
>         glBegin(GL_LINE_LOOP);
>         for(Polygon::iterator
>         
> cur=sum.outer_boundary().vertices_begin();cur!=sum.outer_boundary().vertices_end();cur++)
>         {
>          glVertex2f(cur->x(),cur->y());
>         }
>         glEnd();
>         glFlush();
>         }
>         else
>         {
>         for (Polygon_with_holes::Hole_iterator
>         iter=sum.holes_begin();iter!=sum.holes_end();++iter)
>         {
>         Polygon::iterator piter=iter->vertices_begin();
>         glBegin(GL_LINE_LOOP);
>         for(;piter!=iter->vertices_end();piter++)
>         {
>         double temp_x=piter->x();
>         double temp_y=piter->y();
>         glVertex2f(temp_x,temp_y);
>         }
>         glEnd();
>         }
>         }
>         sum.clear();
>         s_temp.clear();
>         t_temp.clear();
>         if(s_temp.is_empty())
>         {
>         cout<<"empty "<<endl;
>         }
>         if(t>1.0||t<0.1)
>         {
>         delt=-delt;
>         }
>         }
>         }
>
>
>
>     -- 
>      ____  _        ____             _
>     /_____/_) o    /__________  __  //
>     (____ (   (    (    (_/ (_/-(-'_(/
>                           _/
>
>
>     -- 
>     You are currently subscribed to cgal-discuss.
>     To unsubscribe or access the archives, go to
>     https://lists-sop.inria.fr/wws/info/cgal-discuss