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             SIS 0.5  - Single  Image  Stereogram  generator
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     Sis generates 3-D pictures, which you can view by converging your eyes
     to  a  more  distant  point  than  the  screen and focusing on screen-
     distance.  Invoked with the -m option, sis adds two triangles  to  the
     top  of the picture, which help you to find the right convergence.  If
     you know those "Magic Eye" books, you know what to  do.   By  default,
     the background of the SIS is random black-white dots.  You can read in
     arbitrary pictures (called texture-maps) using the -t option.  Texture
     maps  with  a  close  change  of information give better results.  The
     depth  information of the 3-D objects is read from  a  greyscale  pic-
     ture  like those in the directory depth_maps. Black is far away, white
     is near.  Creating good (smooth) deapth_maps is some kind of  problem,
     you  may  use a ray-tracer like povray.  I took the SIS-algorithm from
     an article in the german computer journal c't from july 1994, correct-
     ed  and improved it. If you know other algorithms - I'm very interest-
     ed.

SUPPORTED FILE FORMATS:

  tiff - for input, output and texture.
  tga  - for input.

REQUIREMENTS:

  * libgr (Version 1.3 works fine) - comes with slackware.

INSTALLATION:

A binary compiled with gcc 2.5.8 under linux 1.0.9 is included. If you want
to build it from the sources:

  * Edit the Makefile to change the path for libgr, and where you may want
    to install the binary and man-page.
  * type 'make'.
  * type 'make install' to install the binary and man-page (must be logged
    in as root).

If everything went o.k., produce your first SIS with:

     sis death_maps/oval.tif out.tif -m


PRINTING A SIS:

  You  can  size  and choose the resolution of your SIS with the -x, -y op-
  tions.
  If your printer has 300dpi, type:

     sis -x40i300 -y30i300

  which gives a picture of size 4x3 inch at 300 dpi. Note that 40 means
  40 tenths of an inch = 4 inch.
  Convert it to postscript (for example with xv) and print it with
  ghostscript.

Suggestions,  bugs,  improvements,  questions,  new  sis-algorithms,  fancy
depth-  and texture-maps, please contact me (One of the following addresses
may work):

     bakkerjg@cip11.mathematik.uni-stuttgart.de

     joerg@hatnix.mathematik.uni-stuttgart.de

     zcll1122@rpool4.rus.uni-stuttgart.de

Stuttgart, Feb 1995.
