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diff --git a/hacks/glx/etruscanvenus.man b/hacks/glx/etruscanvenus.man deleted file mode 100644 index 9517274..0000000 --- a/hacks/glx/etruscanvenus.man +++ /dev/null @@ -1,372 +0,0 @@ -.TH XScreenSaver 1 "" "X Version 11" -.SH NAME -etruscanvenus \- Draws a 3d immersion of a Klein bottle that smoothly -deforms between the Etruscan Venus surface, the Roman surface, the Boy -surface surface, and the Ida surface. -.SH SYNOPSIS -.B etruscanvenus -[\-display \fIhost:display.screen\fP] -[\-install] -[\-visual \fIvisual\fP] -[\-window] -[\-root] -[\-delay \fIusecs\fP] -[\-fps] -[\-mode \fIdisplay-mode\fP] -[\-wireframe] -[\-surface] -[\-transparent] -[\-appearance \fIappearance\fP] -[\-solid] -[\-distance-bands] -[\-direction-bands] -[\-colors \fIcolor-scheme\fP] -[\-onesided-colors] -[\-twosided-colors] -[\-distance-colors] -[\-direction-colors] -[\-no-change-colors] -[\-view-mode \fIview-mode\fP] -[\-walk] -[\-turn] -[\-no-deform] -[\-deformation-speed \fIfloat\fP] -[\-initial-deformation \fIfloat\fP] -[\-etruscan-venus] -[\-roman] -[\-boy] -[\-ida] -[\-orientation-marks] -[\-projection \fImode\fP] -[\-perspective] -[\-orthographic] -[\-speed-x \fIfloat\fP] -[\-speed-y \fIfloat\fP] -[\-speed-z \fIfloat\fP] -[\-walk-direction \fIfloat\fP] -[\-walk-speed \fIfloat\fP] -.SH DESCRIPTION -The \fIetruscanvenus\fP program shows a 3d immersion of a Klein bottle -that smoothly deforms between the Etruscan Venus surface, the Roman -surface, the Boy surface, and the Ida surface. You can walk on the -Klein bottle or turn it in 3d. Topologically, all surfaces are Klein -bottles, even the Roman and Boy surfaces, which are doubly covered and -therefore appear to be an immersed real projective plane. The smooth -deformation between these surfaces was constructed by George -K. Francis. -.PP -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). Since all the -surfaces except the Ida surface have points where the surface normal -is not well defined for some points, walking is only performed on the -Ida surface. -.PP -As mentioned above, the Roman and Boy surfaces are doubly covered and -therefore appear to be an immersed real projective plane. Since some -of the parameter names are based on this interpretation of the -surface, the geometry of the real projective plane will be briefly -disussed. The real projective plane is a model for the projective -geometry in 2d space. One point can be singled out as the origin. A -line can be singled out as the line at infinity, i.e., a line that -lies at an infinite distance to the origin. The line at infinity is -topologically a circle. Points on the line at infinity are also used -to model directions in projective geometry. Direction and distance -bands refer to this interpretation of the surface. If direction bands -are used, the bands extend from the origin of the projective plane in -different directions to the line at infinity and back to the origin. -If distance bands are used, the bands lie at constant distances to the -origin. The same interpretation is used for distance and direction -colors. Although there is no conceptually equivalent geometric -interpretation for the two Klein bottle surfaces (the Etruscan Venus -and Ida surfaces), the smooth deformation between the surfaces results -in a natural extension of these concepts to the Klein bottle surfaces. -.PP -The immersed surfaces can be projected to the screen either -perspectively or orthographically. When using the walking mode, -perspective projection to the screen will be used. -.PP -There are three display modes for the Klein bottle: mesh (wireframe), -solid, or transparent. Furthermore, the appearance of the surface can -be as a solid object or as a set of see-through bands. The bands can -be distance bands or direction bands, as explained above. -.PP -The colors with with the surface is drawn can be set to one-sided, -two-sided, distance, or direction. In one-sided mode, the surface is -drawn with the same color on both sides of the underlying triangles. -In two-sided mode, the surface is drawn with one color on one side of -the underlying triangles and the complementary color on the other -side. Since the surface actually only has one side, the color jumps -from red to green along a line on the surface. This mode enables you -to see that the surface is non-orientable. In distance mode, the -surface is displayed with fully saturated colors that depend on the -distance of the points on the projective plane to the origin, as -described above. If the surface is displayed as distance bands, each -band will be displayed with a different color. In direction mode, the -surface is displayed with fully saturated colors that depend on the -angle of the points on the projective plane with respect to the origin -(see above for an explanation). If the surface is displayed as -direction bands, each band will be displayed with a different color. -The colors used to color the surface can either be static or can be -changed dynamically. -.PP -The rotation speed for each of the three coordinate axes around which -the Klein bottle rotates can be chosen. -.PP -Furthermore, in the walking mode the walking direction in the 2d base -square of the surface and the walking speed can be chosen. The -walking direction is measured as an angle in degrees in the 2d square -that forms the coordinate system of the surface. A value of 0 or 180 -means that the walk is along a circle at a randomly chosen distance -from the origin (parallel to a distance band). A value of 90 or 270 -means that the walk is directly along a direction band. Any other -value results in a curved path along the surface. As noted above, -walking is performed only on the Ida surface. -.PP -By default, the immersion of the Klein bottle smoothly deforms between -the Etruscan Venus surface, the Roman surface, the Boy surface, and -the Ida surface. It is possible to choose the speed of the -deformation. Furthermore, it is possible to switch the deformation -off. It is also possible to determine the initial deformation of the -immersion. This is mostly useful if the deformation is switched off, -in which case it will determine the appearance of the surface. A -value of 0 corresponds to the Etruscan Venus surface, a value of 1000 -to the Roman surface, a value of 2000 to the Boy surface, and a value -of 3000 to the Ida surface. -.PP -This program is inspired by George K. Francis's book "A Topological -Picturebook", Springer, 1987, by George K. Francis's paper "The -Etruscan Venus" in P. Concus, R. Finn, and D. A. Hoffman: "Geometric -Analysis and Computer Graphics", Springer, 1991, and by a video -entitled "The Etruscan Venus" by Donna J. Cox, George K. Francis, and -Raymond L. Idaszak, presented at SIGGRAPH 1989. -.SH OPTIONS -.I etruscanvenus -accepts the following options: -.TP 8 -.B \-window -Draw on a newly-created window. This is the default. -.TP 8 -.B \-root -Draw on the root window. -.TP 8 -.B \-install -Install a private colormap for the window. -.TP 8 -.B \-visual \fIvisual\fP -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. -.TP 8 -.B \-delay \fImicroseconds\fP -How much of a delay should be introduced between steps of the -animation. Default 10000, or 1/100th second. -.TP 8 -.B \-fps -Display the current frame rate, CPU load, and polygon count. -.PP -The following four options are mutually exclusive. They determine how -the Klein bottle is displayed. -.TP 8 -.B \-mode random -Display the Klein bottle in a random display mode (default). -.TP 8 -.B \-mode wireframe \fP(Shortcut: \fB\-wireframe\fP) -Display the Klein bottle as a wireframe mesh. -.TP 8 -.B \-mode surface \fP(Shortcut: \fB\-surface\fP) -Display the Klein bottle as a solid surface. -.TP 8 -.B \-mode transparent \fP(Shortcut: \fB\-transparent\fP) -Display the Klein bottle as a transparent surface. -.PP -The following four options are mutually exclusive. They determine the -appearance of the Klein bottle. -.TP 8 -.B \-appearance random -Display the Klein bottle with a random appearance (default). -.TP 8 -.B \-appearance solid \fP(Shortcut: \fB\-solid\fP) -Display the Klein bottle as a solid object. -.TP 8 -.B \-appearance distance-bands \fP(Shortcut: \fB\-distance-bands\fP) -Display the Klein bottle as see-through bands that lie at increasing -distances from the origin (see above for an explanation). -.PP -.TP 8 -.B \-appearance direction-bands \fP(Shortcut: \fB\-direction-bands\fP) -Display the Klein bottle as see-through bands that lie at increasing -angles with respect to the origin (see above for an explanation). -.PP -The following five options are mutually exclusive. They determine how -to color the Klein bottle. -.TP 8 -.B \-colors random -Display the Klein bottle with a random color scheme (default). -.TP 8 -.B \-colors onesided \fP(Shortcut: \fB\-onesided-colors\fP) -Display the Klein bottle with a single color. -.TP 8 -.B \-colors twosided \fP(Shortcut: \fB\-twosided-colors\fP) -Display the Klein bottle with two colors: one color on one "side" and -the complementary color on the "other side." -.TP 8 -.B \-colors distance \fP(Shortcut: \fB\-distance-colors\fP) -Display the Klein bottle with fully saturated colors that depend on -the distance of the points on the projective plane to the origin (see -above for an explanation). If the Klein bottle is displayed as -distance bands, each band will be displayed with a different color. -.TP 8 -.B \-colors direction \fP(Shortcut: \fB\-direction-colors\fP) -Display the Klein bottle with fully saturated colors that depend on -the angle of the points on the projective plane with respect to the -origin (see above for an explanation). If the Klein bottle is -displayed as direction bands, each band will be displayed with a -different color. -.PP -The following options determine whether the colors with which the -Klein bottle are displayed are static or are changing dynamically. -.TP 8 -.B \-change-colors -Change the colors with which the Klein bottle is displayed -dynamically (default). -.TP 8 -.B \-no-change-colors -Use static colors to display the Klein bottle. -.PP -The following three options are mutually exclusive. They determine -how to view the Klein bottle. -.TP 8 -.B \-view-mode random -View the Klein bottle in a random view mode (default). The walking -mode will be randomly selected in approximately 10% of the cases. -.TP 8 -.B \-view-mode turn \fP(Shortcut: \fB\-turn\fP) -View the Klein bottle while it turns in 3d. -.TP 8 -.B \-view-mode walk \fP(Shortcut: \fB\-walk\fP) -View the Klein bottle as if walking on its surface. -.PP -The following options determine whether the surface is being deformed. -.TP 8 -.B \-deform -Deform the surface smoothly between the Etruscan Venus surface, the -Roman surface, the Boy surface surface, and the Ida surface (default). -.TP 8 -.B \-no-deform -Don't deform the surface. -.PP -The following option determines the deformation speed. -.TP 8 -.B \-deformation-speed \fIfloat\fP -The deformation speed is measured in percent of some sensible maximum -speed (default: 10.0). -.PP -The following options determine the initial deformation of the -surface. As described above, this is mostly useful if -\fB\-no-deform\fP is specified. -.TP 8 -.B \-initial-deformation \fIfloat\fP -The initial deformation is specified as a number between 0 and 4000. -A value of 0 corresponds to the Etruscan Venus surface, a value of -1000 to the Roman surface, a value of 2000 to the Boy surface, and a -value of 3000 to the Ida surface. The default value is 0. -.TP 8 -.B \-etruscan-venus -This is a shortcut for \fB\-initial-deformation 0\fP. -.TP 8 -.B \-roman -This is a shortcut for \fB\-initial-deformation 1000\fP. -.TP 8 -.B \-boy -This is a shortcut for \fB\-initial-deformation 2000\fP. -.TP 8 -.B \-ida -This is a shortcut for \fB\-initial-deformation 3000\fP. -.PP -The following options determine whether orientation marks are shown on -the Klein bottle. -.TP 8 -.B \-orientation-marks -Display orientation marks on the Klein bottle. -.TP 8 -.B \-no-orientation-marks -Don't display orientation marks on the Klein bottle (default). -.PP -The following three options are mutually exclusive. They determine -how the Klain bottle is projected from 3d to 2d (i.e., to the screen). -.TP 8 -.B \-projection random -Project the Klein bottle from 3d to 2d using a random projection mode -(default). -.TP 8 -.B \-projection perspective \fP(Shortcut: \fB\-perspective\fP) -Project the Klein bottle from 3d to 2d using a perspective projection. -.TP 8 -.B \-projection orthographic \fP(Shortcut: \fB\-orthographic\fP) -Project the Klein bottle from 3d to 2d using an orthographic -projection. -.PP -The following three options determine the rotation speed of the Klein -bottle around the three possible axes. 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. -.TP 8 -.B \-speed-x \fIfloat\fP -Rotation speed around the x axis (default: 1.1). -.TP 8 -.B \-speed-y \fIfloat\fP -Rotation speed around the y axis (default: 1.3). -.TP 8 -.B \-speed-z \fIfloat\fP -Rotation speed around the z axis (default: 1.5). -.PP -The following two options determine the walking speed and direction. -.TP 8 -.B \-walk-direction \fIfloat\fP -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: 83.0). A value of 0 or 180 means that the walk is -along a circle at a randomly chosen distance from the origin (parallel -to a distance band). A value of 90 or 270 means that the walk is -directly along a direction band. Any other value results in a curved -path along the surface. As noted above, walking is performed only on -the Ida surface. -.TP 8 -.B \-walk-speed \fIfloat\fP -The walking speed is measured in percent of some sensible maximum -speed (default: 20.0). -.SH 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. 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 walk -mode. -.SH ENVIRONMENT -.PP -.TP 8 -.B DISPLAY -to get the default host and display number. -.TP 8 -.B XENVIRONMENT -to get the name of a resource file that overrides the global resources -stored in the RESOURCE_MANAGER property. -.SH SEE ALSO -.BR X (1), -.BR xscreensaver (1) -.SH COPYRIGHT -Copyright \(co 2019-2020 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. -.SH AUTHOR -Carsten Steger <carsten@mirsanmir.org>, 05-jan-2020. |