% This work may be distributed and/or modified under the
%% conditions of the LaTeX Project Public License, either version 1.3
%% of this license or (at your option) any later version.
%%
%% Author:   Manuel Luque <manuel.luque27@gmail.com>
%%           Herbert Voß <hvoss@tug.org>   
%%
% les macros de Jean-Paul
%% syntaxe : array isobarycentre3d --> G
/isobarycentre3d {
2 dict begin
   /table exch def
   /n table length 3 idiv def
   table 0 getp3d
   1 1 n 1 sub {
       table exch getp3d
       addv3d
   } for
   1 n div mulv3d
end
} def
%%%%% ### get3d ###
/getp3d { %% [tableau de points 3d] i --> donne le ieme point du tableau
   2 copy 2 copy
   3 mul get
   5 1 roll
   3 mul 1 add get
   3 1 roll
   3 mul 2 add get
} def
%%%%% ### addv3d ###
%% addition de deux vecteurs 3d
/addv3d { %% x1 y1 z1 x2 y2 z2
6 dict begin
   /zp exch def
   /yp exch def
   /xp exch def
   /z exch def
   /y exch def
   /x exch def
   x xp add
   y yp add
   z zp add
end
} def
%%%%% ### mulv3d ###
%% (scalaire)*(vecteur 3d) Attention : dans l autre sens !
/mulv3d { %% x y z lambda
4 dict begin
   /lambda exch def
   /z exch def
   /y exch def
   /x exch def
   x lambda mul
   y lambda mul
   z lambda mul
end
} def