// Last edited on 2024-05-01 21:43:57 by stolfi

#macro scene(ux, uy, uz)
  #local R = 5.0;
  union{
    sphere{ <0,0,0>, R texture{ txg } }
    object{ gab_norm_vec(R, ux, uy, uz, txv) } 
    translate 7*z
  }
#end

#macro gab_norm_vec(R, ux, uy, uz, tx)
  #local dir = < ux, uy, uz >;
  #local pos = R*dir;
  #local rad = rad_arrow;
  union{
    sphere{ pos, 1.5*rad texture{ tx } }
    object{ garrow(pos, dir, tx) }
  }
#end