1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
|
verbatimtex
%&latex
\documentclass{article}
\begin{document}
etex
input 3danim
input 3dgeom
output_res:=72;
drawing_scale:=20cm;
vardef def_C(expr inst)=
new_obj_points(inst,21); % 21 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);
% corners of the projection plane
%set_point(9)(12.92993,12.37372,6.83334);
%set_point(10)(15.68588,8.48413,6.8334);
%set_point(11)(16.27899,8.90436,4.12851);
%set_point(12)(13.52304,12.79395,4.12845);
%set_point(9)(13.76718,11.50638,6.15714);
%set_point(10)(15.14517,9.56158,6.15717);
%set_point(11)(15.44174,9.7717,4.80472);
%set_point(12)(14.06375,11.71649,4.80469);
set_point(9)(0.80682,2.27571,1.939);
set_point(10)(2.03946,0.2357,1.93903);
set_point(11)(2.46796,0.49461,0.63113);
set_point(12)(1.23532,2.53462,0.6311);
% shown observator
set_point(13)(3.23608,2.35114,2);
% intersections with the projection plane
new_plane(pl)(9,10,11);
new_line(l)(1,13);
if not def_inter_p_l_pl(14)(l)(pl):
message "PROBLEM ";
fi;
set_line(l)(2,13);
if not def_inter_p_l_pl(15)(l)(pl):
message "PROBLEM ";
fi;
set_line(l)(3,13);
if not def_inter_p_l_pl(16)(l)(pl):
message "PROBLEM ";
fi;
set_line(l)(4,13);
if not def_inter_p_l_pl(17)(l)(pl):
message "PROBLEM ";
fi;
set_line(l)(5,13);
if not def_inter_p_l_pl(18)(l)(pl):
message "PROBLEM ";
fi;
set_line(l)(6,13);
if not def_inter_p_l_pl(19)(l)(pl):
message "PROBLEM ";
fi;
set_line(l)(7,13);
if not def_inter_p_l_pl(20)(l)(pl):
message "PROBLEM ";
fi;
set_line(l)(8,13);
if not def_inter_p_l_pl(21)(l)(pl):
message "PROBLEM ";
fi;
free_line(l);
free_plane(pl);
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);
draw_lines(9,10,11,12,9);
pickup pencircle scaled 2pt;
draw_line(13,13);draw_line(1,1);draw_line(2,2);draw_line(3,3);draw_line(7,7);
pickup pencircle scaled .4pt;
draw fullcircle scaled 6pt shifted z[ipnt_(8)];
label_obj.lft(btex \textit{Obs}$(3.23,2.35,2)$ etex,13);
label_obj.rt(btex $(0,0,0)$ etex,1);
label_obj.rt(btex $(0,0,1)$ etex,2);
label_obj.bot(btex $(0,1,0)$ etex,3);
label_obj.llft(btex $(1,1,0)$ etex,7);
drawoptions(dashed withdots);
draw_line(1,13);draw_line(2,13);draw_line(3,13);draw_line(4,13);
draw_line(5,13);draw_line(6,13);draw_line(7,13);draw_line(8,13);
drawoptions();
draw_line(14,15,17,16,14);draw_lines(18,19,21,20,18);
draw_line(14,18);draw_line(15,19);draw_line(16,20);draw_line(17,21);
enddef;
assign_obj("cube","C");
for i:=28 upto 28:
beginfig(100+i);
% Observator
set_point_(Obs)(20*cosd(3.6*i),20*sind(3.6*i),4);
show_point("Obs",Obs);
Obs_phi:=90;Obs_dist:=2;point_of_view_obj("cube",14,Obs_phi);
draw_obj("cube");
endfig;
endfor;
end.
|