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Remember to read INTRO and INSTALL before this.

For more information, read the man pages using something like
"nroff -man xpgs.6 | more". In particular, xpgs.6 contains an
overview of this suite of programs. For those without nroff (such as
DEC VMS users), I have provided an abridged version of the man pages
in xpgs.txt.

In general, if you get stuck read what's on the screen when the program
starts. In the interactive X programs (xpgs, vpgs, xss) all keypresses,
during program execution, must be done in the graphics window. Be sure that
the programs (xpgs & vpgs) has finished the SIRDS generation (ie. after the
"all done" message), otherwise the keypresses are buffered and not acted
upon until the initial task is done.

Otherwise use the "-h" option to give yourself a summary of command line
options, eg "xpgs -h". Note all options can be abbreviated to the least
number of letters to be unique, clashes are resolved in the order of
the options shown in the help.

For beginners, xpgs has a SHIMMER mode which depicts the same SIRDS but
changes the background pixels. It aids the initial viewing of a SIRDS if you
haven't seen one before.

  To view a single SIRDS frame of a tetrahedron,
  try "xpgs tet" for wide-eyed (WE) viewing
      "xpgs -S tet"  for WE with the SHIMMER mode
  or  "xpgs -e 0.5 -m 0.4 -b 0.0 -r tet" for cross-eyed (CE) setting the
      background plane to be at the origin.

* I haven't been able to check if the CE viewing works because I can't see
* them in this way. If someone could try them out and email me with any
* problems, I'll be most grateful.

  You can tweak the various options to get the SIRDS just right.
  For CE viewing, the object size must be reduced by at least a
  factor of two, i.e. set "-m 0.5". Also the depth effect must be
  reduced by a similar amount, set "-e 0.5".

  These suggested values are not necessary true for any image,
  you will have to experiment to find the right settings.

A quick tour to see a dinosaur:
  1) tweak the .xss file using "xss dino" and save the result.
  2) view the SIRDS animation (you can save a particular frame in here)
      "xpgs -f 5 dino"
  3) create a depth map
      "cvtoppm -g 320x200 dino dino.pgm"
  4) view the SIRDS of the depth map
      "vpgs dino.pgm"
  5) finally create a colour SIRDS
     using xss file
      "sisgen -R 2 dino -o | xv -"
     using pgm file
      "sisgen -R 2 -d dino.pgm -o | xv -"

  There are two ways to dump the SIRDS image -
       a)  xbm which can be potentially huge.
       b)  Postscript which eats up about 320K in default settings.

  We have bundled some objects for you to try out -
  regular solids in polyh format and a couple of objects converted from
  X3d v2.0 objects and Wavefront objects. Also there are a number of builtin
  objects which you can access in xss.

  More objects can be found at avalon ftp site or its mirrors
  such as the one at wuarchive. See the INTRO file for the full names
  and IP numbers.

  If you have compiled xpgs with the XPGSUSEPM option, the number of frames
  of animation possible depends on the X server memory allocation, ie. the
  number of big Pixmaps it can support. If your server can't handle a large
  number then give xpgs a smaller number of frames, eg. "-f 3".
  Alternatively, recompile xpgs without the XPGSUSEPM option.

  If your SIRDS don't look random then read the notes in INSTALL about the
  SILLYRAND compilation option.