//
// a cylindric wall
//

#version 3.1;

global_settings
{
  assumed_gamma 1.0
}

camera
{
  location  <-7, 4, -7.0>
  look_at   <-1, 2.0,  -1>
}

light_source
{ <-40,40,0>
  color rgb <1,1,1>
}

sky_sphere
{
  pigment
  {
    gradient y
    color_map { [0.0 color blue 0.6] [1.0 color rgb 1] }
  }
}

plane {y,0
        pigment {color rgb <.2,.6,.2>}
}

//
// parameters : you can play with
// but be careful of light and camera positions.
//
#declare Nb_p=40; // number of pieces
#declare Rayon=12; // radius of the cylindric wall : be careful of light and camera position
#declare Rapport=20; // rapport entre la largeur de la plaque et epaisseur du croisillon :
                     // sorry no english
#declare Haut_Tot=7; // the wall is 7 units high  
//
// the maths
//
#declare Ang_b=360/Nb_p;
#declare Largeur=2*Rayon*sin(radians(Ang_b/2));
#declare Distance=Rayon*cos(radians(Ang_b/2));
// a piece is a square
// but the wall must be 7 units high !!!
// so i resize it if necessary
#declare Nb_Cop=int(Haut_Tot/Largeur);
#if (Nb_Cop != Haut_Tot/Largeur)
        #if (Nb_Cop<1)
                #declare Nb_Cop=1;
        #end
        #declare Hauteur=Haut_Tot/Nb_Cop;
#end
#declare Paroi=difference {
        box{<-Largeur/2,0,0>,<Largeur/2,Hauteur,.2>}
        box{<-Largeur/2+Largeur/(Rapport*2),Largeur/(Rapport*2),-.1>,
        <Largeur/2-Largeur/(Rapport*2),Hauteur-Largeur/(Rapport*2),.15>}
}
#declare Mur=union {
        #declare Nb=1;
        #while (Nb<Nb_p+1)
                #declare Nb1=1;
                #while (Nb1<Nb_Cop+1)
                        object { Paroi
                                translate (Nb1-1)*Hauteur*y+Distance*z
                                rotate (360/Nb_p)*Nb*y
                        }
                        #declare Nb1=Nb1+1;
                #end
                #declare Nb=Nb+1;
        #end
}
//
// The wall
//
object { Mur
        pigment {color rgb <1,1,0>}
        finish {specular .5 roughness 0.04}
}