Author: Laurence D. Finston

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Last updated: April 29, 2006

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**sphere_1.ldf**. Indented version (plain text).

circle c[];

division_value := 64;

one_quarter_division_value := 1/4division_value;

three_quarters_division_value := 3/4division_value;

set c0 with_point_count division_value;

scale c0 (8, 0, 8);

rotate c0 by 90;

point p;

path q[];

p := get_point 0 c0;

q[division_value] += p;

pen thick_pen;

thick_pen := pencircle scaled (3.5, 3.5, 3.5);

pickup thick_pen;

step_value := 360 / division_value;

j := 1;

for i = 0 step step_value until 360 - step_value:

rotate c0 (0, step_value);

if (is_even j):

draw c0;

fi;

for k = 2 step 2 until one_quarter_division_value - 2:

q[k] += get_point (k) c0;

q[three_quarters_division_value + k]

+= get_point (three_quarters_division_value + k) c0;

endfor;

q[division_value] += get_point 0 c0;

j += 1;

endfor;

q[division_value] += cycle;

q[division_value] += ..;

draw q[division_value];

for i = 2 step 2 until one_quarter_division_value - 2:

q[i] += ..;

q[i] += cycle;

q[three_quarters_division_value + i] += ..;

q[three_quarters_division_value + i] += cycle;

draw q[i];

draw q[three_quarters_division_value + i];

endfor;

rotate current_picture by -25;

picture save_picture;

save_picture := current_picture;

clear current_picture;

message "Starting figures.";

for i = 1 upto 35:

rotate save_picture (0, 10);

beginfig(i);

output save_picture;

endfig;

message "Finished figure:";

show i;

endfor;

verbatim_metapost "bye;";

end;

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Indented version (plain text).

The images in PDF format: ships_1.pdf

2005-04-07.
The images in a compressed (gzipped) PostScript file:
ships_1.ps.gz

I find this format to be the most convenient. By pressing the
page down

button repeatedly in Ghostview, or holding it down,
one has the effect of flipping through

animation drawings.
I tried to generate an animated MNG file, but it failed when I tried
to use more than 10 input files. I'll have to look into a better way
of creating animations.

reg_polygon p;

reg_polygon q;

focus f;

set f with_position (-5, 10, -10) with_direction (-5, 10, 10) with_distance 10;

p := unit_pentagon scaled 5 rotated (0, 20) shifted (0, 0, -5);

q := unit_hexagon scaled 5 rotated (90, 20) shifted (0, 1, 3);

beginfig(0);

path r;

r := (-5, -22) -- (15, -22) -- (15, 7) -- (-5, 7) -- cycle;

undraw r;

output current_picture with_focus f;

verbatim_metapost "boxit.b(currentpicture); path p; p = bpath(b);";

clear current_picture;

endfig;

for i = 1 upto 10:

beginfig(i);

shift p (0, 0, 3);

filldraw p with_draw_color red with_fill_color green;

filldraw q with_draw_color blue with_fill_color yellow;;

verbatim_metapost "undraw p;";

endfig with_focus f with_surface_hiding;

endfor;

end;

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Indented version (plain text).

beginfig(1);

circle c[];

division_value := 64;

one_quarter_division_value := 1/4division_value;

three_quarters_division_value := 3/4division_value;

set c0 with_point_count division_value;

scale c0 (8, 0, 8);

rotate c0 by 90;

point p;

path q[];

q[division_value] += get_point 0 c0;

pen thick_pen;

thick_pen := pencircle scaled (2.5, 2.5, 2.5);

pickup thick_pen;

step_value := 360 / division_value;

j := 1;

for i = 0 step step_value until 360 - step_value:

rotate c0 (0, step_value);

if (is_even j):

draw c0;

fi;

for k = 2 step 2 until one_quarter_division_value - 2:

q[k] += get_point (k) c0;

q[three_quarters_division_value + k]
+= get_point (three_quarters_division_value + k) c0;

endfor;

q[division_value] += get_point 0 c0;

j += 1;

endfor;

q[division_value] += cycle;

q[division_value] += ..;

draw q[division_value];

for i = 2 step 2 until one_quarter_division_value - 2:

q[i] += ..;

q[i] += cycle;

q[three_quarters_division_value + i] += ..;

q[three_quarters_division_value + i] += cycle;

draw q[i];

draw q[three_quarters_division_value + i];

endfor;

rotate current_picture (-45, -15);

endfig;

end;

**Sphere**

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[LDF 2005.01.10.] I made this image with GNU 3DLDF 1.1.5.1, and I don't think I saved the code I used.

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