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% D. Roegel January 2001
% roegel@loria.fr
input 3danim
input 3dgeom
output_res:=72;
drawing_scale:=2cm;
vardef def_C(expr inst)=
new_obj_points(inst,12); % 12 points
set_C_points(inst);
enddef;
vardef set_C_points(expr inst)=
set_point(1)(0,0,0);set_point(2)(0,0,1);
set_point(3)(0,1,0);set_point(4)(0,1,1);
set_point(5)(1,0,0);set_point(6)(1,0,1);
set_point(7)(1,1,0);set_point(8)(1,1,1);
% vanishing points
def_screen_pl(screen);
new_line(l)(1,2);
if not def_vanishing_point_p_l_pl(9)(l)(screen):
message "no vanishing point 1";
set_point(9)(0,0,0);
fi;
set_line(l)(1,3);
if not def_vanishing_point_p_l_pl(10)(l)(screen):
message "no vanishing point 2";
set_point(10)(0,0,0);
fi;
set_line(l)(1,5);
if not def_vanishing_point_p_l_pl(11)(l)(screen):
message "no vanishing point 3";
set_point(11)(0,0,0);
fi;
set_line(l)(1,7);
if not def_vanishing_point_p_l_pl(12)(l)(screen):
message "no vanishing point 4";
set_point(12)(0,0,0);
fi;
free_line(l);
enddef;
vardef draw_C(expr inst)=
draw_lines(1,2,4,3,1);draw_lines(5,6,8,7,5);
draw_line(1,5);draw_line(2,6);draw_line(3,7);draw_line(4,8);
pickup pencircle scaled 4pt;
drawoptions(withcolor red);
if z[ipnt_(9)]=(10,10):draw_line(9,9);
fi;
if z[ipnt_(10)]=(10,10):draw_line(10,10);
fi;
if z[ipnt_(11)]=(10,10):draw_line(11,11);
fi;
if z[ipnt_(12)]=(10,10):draw_line(12,12);
fi;
drawoptions();
pickup pencircle scaled 1pt;
draw_line(9,9);draw_line(10,10);draw_line(11,11);draw_line(12,12);
pickup pencircle scaled 0.4pt;
drawoptions(dashed evenly scaled 0.5);
for j:=1,3,5,7:draw_line(j,9);endfor;
for j:=3,4,7,8:draw_line(j,10);endfor;
for j:=1 upto 4:draw_line(j,11);endfor;
draw_line(1,12);draw_line(2,12);
drawoptions();
enddef;
new_plane_(screen)(0,0,0); % must be defined before |assign_obj|
% because |assign_obj| calls |set_C_point|
% on change le champ car on est très près
h_field:=160; % degrees
v_field:=160; % degrees
assign_obj("cube","C");
%for i:=0 upto 100:
i=97;
beginfig(100+i);
% Observator
set_point_(Obs)(1.8*cosd(3.6*i),1.8*sind(3.6*i),2);
Obs_phi:=90;Obs_dist:=0.5;point_of_view_obj("cube",8,Obs_phi);
reset_obj("cube");
draw_obj("cube");
endfig;
%endfor;
end.
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