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- RCS $Id: README,v 1.13 1994/06/02 17:19:20 tuna Exp $
-
- README file for xearth, version 0.92
- Kirk Lauritz Johnson <tuna@cag.lcs.mit.edu>
- 1 June 1994
-
-
- WHAT IS IT?
-
- Xearth sets the X root window an image of the Earth, as seen from
- your favorite vantage point in space, correctly shaded for the
- current position of the Sun. By default, xearth updates the
- displayed image every five minutes; the time between updates can
- be changed using either X resources or a command line
- option. Xearth can also render directly into PPM and GIF files
- instead of drawing in the root window; see the man page for
- details.
-
- See the HISTORY file for a list of changes since versions 0.5 and
- 0.92.
-
-
- IMPORTANT!
-
- This version of xearth (version 0.92) is an evolution of the only
- version(s) of xearth that I ever released (versions 0.5, 0.9, and
- 0.91). Unfortunately, some net.weenies chose to make some minor
- mods (and introduce bugs!) and "release" a bogus version 0.6
- without even notifying or consulting with me; this may be the
- version of xearth that you are currently using.
-
- Some of the command line options supported in the bogus version
- 0.6 (e.g, those having to do with "geostatic") don't exist in this
- version -- their functionality (and more!) is available through
- other means. In addition, the meaning and syntax of some of the
- xearth command line options have changed, so you should probably
- give the new man page a good reading if things don't seem to be
- working as you expect.
-
-
- MAJOR CAVEAT
-
- This version of xearth (version 0.92) supports both one- and
- eight-bit framebuffers. Systems with other than one- and eight-bit
- framebuffers are only "supported" (indirectly) to the extent that
- xearth can generate PPM and GIF files that can be fed directly
- into your favorite image viewer (e.g., xv, xloadimage).
-
-
- WHERE TO GET IT?
-
- The latest-and-greatest version of xearth should be available via
- anonymous ftp from cag.lcs.mit.edu:/pub/tuna (or, for those web
- surfers out there, via a link from the xearth WWW home page
- http://cag-www.lcs.mit.edu/~tuna/xearth/index.html).
-
-
- NOTES
-
- If you are trying to build xearth under SunOS 4.x using /bin/cc,
- make sure to read the section of the INSTALL file entitled
- "BUILDING UNDER SUNOS 4.x" regarding a compiler bug.
-
- There are a number of improvements that I'd love to make, but I
- really should be working on my thesis instead of hacking on this.
-
- The map information used in xearth was derived from the "CIA World
- Data Bank II map database," as taken from some "cbd" files that
- were apparently originally generated by Brian Reid at DECWRL.
-
- Running in the background on a Sun 4/110, xearth requires around
- 30 CPU seconds each time it redraws an image in the root window.
- With the default time-between-redraws of 300 seconds, I hardly
- even notice the extra CPU load. Your mileage may vary, of course,
- especially on slower machines.
-
- The Graphics Interchange Format(c) is the Copyright property of
- CompuServe Incorporated. GIF(sm) is a Service Mark property of
- CompuServe Incorporated.
-
- Thanks to Jamie Zawinski for suggesting that I look at his
- xscreensaver package for a good example of how to use the resource
- and command line option parts of Xt; his code saved me piles of
- lossage.
-
- Kudos to Jef Poskanzer for his excellent PBMPLUS toolkit.
-
-
- IDEAS FOR FUTURE WORK
-
- Support for other visual classes and depths.
-
- Better error recovery (better than "assert()", anyway).
-
- Add options/resources that specify colors other than the default
- green, blue, red, white, and black.
-
- Add hooks for user-specified marker locations.
-
- Code for tracking real-life orbits ("-pos hubble").
-
- Support for supersampling/antialiasing.
-
-
- AUTHOR
-
- Kirk Johnson <tuna@cag.lcs.mit.edu>
-
- Patches, bug reports, and suggestions are welcome, although I
- can't guarantee that I'll get around to doing anything about them
- in a timely fashion.
-
-
- LEGAL STUFF
-
- Copyright (C) 1989, 1990, 1993, 1994 by Kirk Lauritz Johnson
-
- Portions of the xearth source code, as marked, are:
- Copyright (C) 1989, 1990, 1991 by Jim Frost
- Copyright (C) 1992 by Jamie Zawinski <jwz@lucid.com>
-
- 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. The author makes no
- representations about the suitability of this software for any
- purpose. It is provided "as is" without express or implied
- warranty.
-
- THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
- INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
- IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, INDIRECT
- OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
- LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
- NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
- CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-