Options to Xplanet


--help
Display a list of options.

--version
Display version information.

--image image_file
Use image_file as the day map image.

--night_image night_file
Use image_file as the night map image.  If this option is not
specified, the night map will be a copy of the day map, modified as
described in the --shade parameter.

--cloud_image cloud_file
Use cloud_file as the image to be overlaid.

--shade shade
If --night_image is not specified, set the brightness of the night map
to shade percent of the day map.  If shade is 100, the day and night
maps will be identical.

--merc
Render the image as a mercator (flat) projection.

--ortho
Render the image as an orthographic projection.

--animate
Pop up a window using OpenGL or Mesa where the user can rotate the
globe interactively.  Valid keys in this mode are
Home/End:       Move closer/farther
Arrow keys:       Rotate body
+/-:        Increase/decrease rotation speed
r:        Reverse rotation
h:        Toggle help screen
q:        Quit

--ppmfile ppmfile
Write a .ppm file instead of rendering to the root window.

--long longitude
Render the globe as seen from above the specified longitude.
Longitude is positive going east, negative going west.  Los Angeles is
at -118 or 242.  This option implies --ortho.

--lat latitude
Render the globe as seen from above the specified latitude.  This
option implies --ortho.

--dayside
Render the image as seen from directly above the subsolar point.  This
option implies --ortho.

--nightside
Render the image as seen from directly above the anti-subsolar point.  This
option implies --ortho.

--grid spacing
Draw a longitude/latitude grid.  The gridlines will be spaced every
90/spacing degrees.  A grid value of 6 will space longitude/latitude
lines every 15 degrees.

--fuzz fuzz
Let the day and night hemispheres blend into one another within fuzz
pixels of the terminator.  This isn't very realistic as the blending
only occurs in the east-west direction, but it looks better than not
doing it at all.

An image file must be specified.  If none is specified with the
--image option, the name of the day map file is taken from the
hard-coded value in image.cc.  If no other options are specified, the
program defaults to --mercator --shade 30 --fuzz 6.  If --ortho is
specified with no other options, the observer is placed above
longitude 0, latitide 0.

Xplanetroot runs Xplanet every five minutes or other specified
interval.  I did this instead of adding this as an option to Xplanet
since letting Xplanet run all of the time would take up a lot of
memory.  Xplanetroot has mostly the same options as Xplanet without
the --animate or --ppmfile options.  There is also a --wait option,
where the time between updates is specified in seconds.