NAME¶
klein - Draws a 4d Klein bottle.
SYNOPSIS¶
klein [-display
host:display.screen] [-install] [-visual
visual] [-window] [-root] [-delay
usecs] [-fps] [-klein-bottle
bottle-name] [-figure-8] [-squeezed-torus] [-lawson] [-mode
display-mode] [-wireframe] [-surface] [-transparent] [-appearance
appearance] [-solid] [-bands] [-colors
color-scheme] [-twosided]
[-rainbow] [-depth] [-view-mode
view-mode] [-walk] [-turn] [-walk-turn]
[-orientation-marks] [-projection-3d
mode] [-perspective-3d]
[-orthographic-3d] [-projection-4d
mode] [-perspective-4d]
[-orthographic-4d] [-speed-wx
float] [-speed-wy
float]
[-speed-wz
float] [-speed-xy
float] [-speed-xz
float]
[-speed-yz
float] [-walk-direction
float] [-walk-speed
float]
DESCRIPTION¶
The
klein program shows three different Klein bottles in 4d: the figure-8
Klein bottle, the squeezed torus Klein bottle, or the Lawson Klein bottle. You
can walk on the Klein bottle, see it turn in 4d, or walk on it while it turns
in 4d. The figure-8 Klein bottle is well known in its 3d form. The 4d form
used in this program is an extension of the 3d form to 4d that does not
intersect itself in 4d (which can be seen in the depth colors mode). The
squeezed torus Klein bottle also does not intersect itself in 4d (which can be
seen in the depth colors mode). The Lawson Klein bottle, on the other hand,
does intersect itself in 4d. Its primary use is that it has a nice appearance
for walking and for turning in 3d. The Klein bottle is a non-orientable
surface. To make this apparent, the two-sided color mode can be used.
Alternatively, orientation markers (curling arrows) can be drawn as a texture
map on the surface of the Klein bottle. While walking on the Klein bottle, you
will notice that the orientation of the curling arrows changes (which it must
because the Klein bottle is non-orientable). The program projects the 4d Klein
bottle to 3d using either a perspective or an orthographic projection. Which
of the two alternatives looks more appealing depends on the viewing mode and
the Klein bottle. For example, the Lawson Klein bottle looks nicest when
projected perspectively. The figure-8 Klein bottle, on the other hand, looks
nicer while walking when projected orthographically from 4d. For the squeezed
torus Klein bottle, both projection modes give equally acceptable projections.
The projected Klein bottle can then be projected to the screen either
perspectively or orthographically. When using the walking modes, perspective
projection to the screen should be used. There are three display modes for the
Klein bottle: mesh (wireframe), solid, or transparent. Furthermore, the
appearance of the Klein bottle can be as a solid object or as a set of
see-through bands. Finally, the colors with with the Klein bottle is drawn can
be set to two-sided, rainbow, or depth. In the first case, the Klein bottle is
drawn with red on one "side" and green on the "other
side". Of course, the Klein bottle only has one side, so the color jumps
from red to green along a curve on the surface of the Klein bottle. This mode
enables you to see that the Klein bottle is non-orientable. The second mode
draws the Klein bottle with fully saturated rainbow colors. This gives a very
nice effect when combined with the see-through bands mode or with the
orientation markers drawn. The third mode draws the Klein bottle with colors
that are chosen according to the 4d "depth" of the points. This mode
enables you to see that the figure-8 and squeezed torus Klein bottles do not
intersect themselves in 4d, while the Lawson Klein bottle does intersect
itself. The rotation speed for each of the six planes around which the Klein
bottle rotates can be chosen. For the walk-and-turn more, only the rotation
speeds around the true 4d planes are used (the xy, xz, and yz planes).
Furthermore, in the walking modes the walking direction in the 2d base square
of the Klein bottle and the walking speed can be chosen. This program is
somewhat inspired by Thomas Banchoff's book "Beyond the Third Dimension:
Geometry, Computer Graphics, and Higher Dimensions", Scientific American
Library, 1990.
OPTIONS¶
klein accepts the following options:
- -window
- Draw on a newly-created window. This is the default.
- -root
- Draw on the root window.
- -install
- Install a private colormap for the window.
- -visual visual
- Specify which visual to use. Legal values are the name of a visual class,
or the id number (decimal or hex) of a specific visual.
- -delay microseconds
- How much of a delay should be introduced between steps of the animation.
Default 10000, or 1/100th second.
- -fps
- Display the current frame rate, CPU load, and polygon count.
The following three options are mutually exclusive. They determine which Klein
bottle is displayed.
- -klein-bottle random
- Display a random Klein bottle (default).
- -klein-bottle figure-8 (Shortcut:
-figure-8)
- Display the figure-8 Klein bottle.
- -klein-bottle squeezed-torus (Shortcut:
-squeezed-torus)
- Display the squeezed torus Klein bottle.
- -klein-bottle lawson (Shortcut: -lawson)
- Display the Lawson Klein bottle.
The following four options are mutually exclusive. They determine how the Klein
bottle is displayed.
- -mode random
- Display the Klein bottle in a random display mode (default).
- -mode wireframe (Shortcut: -wireframe)
- Display the Klein bottle as a wireframe mesh.
- -mode surface (Shortcut: -surface)
- Display the Klein bottle as a solid surface.
- -mode transparent (Shortcut:
-transparent)
- Display the Klein bottle as a transparent surface.
The following three options are mutually exclusive. They determine the
appearance of the Klein bottle.
- -appearance random
- Display the Klein bottle with a random appearance (default).
- -appearance solid (Shortcut: -solid)
- Display the Klein bottle as a solid object.
- -appearance bands (Shortcut: -bands)
- Display the Klein bottle as see-through bands.
The following four options are mutually exclusive. They determine how to color
the Klein bottle.
- -colors random
- Display the Klein bottle with a random color scheme (default).
- -colors twosided (Shortcut: -twosided)
- Display the Klein bottle with two colors: red on one "side" and
green on the "other side".
- -colors rainbow (Shortcut: -rainbow)
- Display the Klein bottle with fully saturated rainbow colors. If the Klein
bottle is displayed as see-through bands, each band will be displayed with
a different color.
- -colors depth (Shortcut: -depth)
- Display the Klein bottle with colors chosen depending on the 4d
"depth" of the points.
The following four options are mutually exclusive. They determine how to view
the Klein bottle.
- -view-mode random
- View the Klein bottle in a random view mode (default).
- -view-mode walk (Shortcut: -walk)
- View the Klein bottle as if walking on its surface.
- -view-mode turn (Shortcut: -turn)
- View the Klein bottle while it turns in 4d.
- -view-mode walk-turn (Shortcut:
-walk-turn)
- View the Klein bottle as if walking on its surface. Additionally, the
Klein bottle turns around the true 4d planes (the xy, xz, and yz
planes).
The following options determine whether orientation marks are shown on the Klein
bottle.
- -orientation-marks
- Display orientation marks on the Klein bottle.
- -no-orientation-marks
- Don't display orientation marks on the Klein bottle (default).
The following three options are mutually exclusive. They determine how the Klein
bottle is projected from 3d to 2d (i.e., to the screen).
- -projection-3d random
- Project the Klein bottle from 3d to 2d using a random projection mode
(default).
- -projection-3d perspective (Shortcut:
-perspective-3d)
- Project the Klein bottle from 3d to 2d using a perspective
projection.
- -projection-3d orthographic (Shortcut:
-orthographic-3d)
- Project the Klein bottle from 3d to 2d using an orthographic
projection.
The following three options are mutually exclusive. They determine how the Klein
bottle is projected from 4d to 3d.
- -projection-4d random
- Project the Klein bottle from 4d to 3d using a random projection mode
(default).
- -projection-4d perspective (Shortcut:
-perspective-4d)
- Project the Klein bottle from 4d to 3d using a perspective
projection.
- -projection-4d orthographic (Shortcut:
-orthographic-4d)
- Project the Klein bottle from 4d to 3d using an orthographic
projection.
The following six options determine the rotation speed of the Klein bottle
around the six possible hyperplanes. The rotation speed is measured in degrees
per frame. The speeds should be set to relatively small values, e.g., less
than 4 in magnitude. In walk mode, all speeds are ignored. In walk-and-turn
mode, the 3d rotation speeds are ignored (i.e., the wx, wy, and wz speeds). In
walk-and-turn mode, smaller speeds must be used than in the turn mode to
achieve a nice visualization. Therefore, in walk-and-turn mode the speeds you
have selected are divided by 5 internally.
- -speed-wx float
- Rotation speed around the wx plane (default: 1.1).
- -speed-wy float
- Rotation speed around the wy plane (default: 1.3).
- -speed-wz float
- Rotation speed around the wz plane (default: 1.5).
- -speed-xy float
- Rotation speed around the xy plane (default: 1.7).
- -speed-xz float
- Rotation speed around the xz plane (default: 1.9).
- -speed-yz float
- Rotation speed around the yz plane (default: 2.1).
The following two options determine the walking speed and direction.
- -walk-direction float
- The walking direction is measured as an angle in degrees in the 2d square
that forms the coordinate system of the surface of the Klein bottle
(default: 7.0).
- -walk-speed float
- The walking speed is measured in percent of some sensible maximum speed
(default: 20.0).
INTERACTION¶
If you run this program in standalone mode in its turn mode, you can rotate the
Klein bottle by dragging the mouse while pressing the left mouse button. This
rotates the Klein bottle in 3D, i.e., around the wx, wy, and wz planes. If you
press the shift key while dragging the mouse with the left button pressed the
Klein bottle is rotated in 4D, i.e., around the xy, xz, and yz planes. To
examine the Klein bottle at your leisure, it is best to set all speeds to 0.
Otherwise, the Klein bottle will rotate while the left mouse button is not
pressed. This kind of interaction is not available in the two walk modes.
ENVIRONMENT¶
- DISPLAY
- to get the default host and display number.
- XENVIRONMENT
- to get the name of a resource file that overrides the global resources
stored in the RESOURCE_MANAGER property.
SEE ALSO¶
X(1),
xscreensaver(1)
COPYRIGHT¶
Copyright © 2005-2013 by Carsten Steger. Permission to use, copy, modify,
distribute, and sell this software and its documentation for any purpose is
hereby granted without fee, provided that the above copyright notice appear in
all copies and that both that copyright notice and this permission notice
appear in supporting documentation. No representations are made about the
suitability of this software for any purpose. It is provided "as is"
without express or implied warranty.
AUTHOR¶
Carsten Steger <carsten@mirsanmir.org>, 25-dec-2013.