Stereograph for linux, an advanced stereogram generator, v0.10
(c) 2000 by Fabian Januszewski <fabian.linux@januszewski.de>
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Stereograph comes with ABSOLUTELY NO WARRANTY;
This is free software under the GPL, and you are welcome to redistribute it
under certain conditions;


HOW TO INSTALL THIS PACKAGE

See INSTALL for a short reference.


WHAT DOES STEREOGRAPH

Stereograph is a stereogram generator. In detail it is a single image
stereogram (SIS) generator. That's a program that produces twodimensional
images that seem to be threedimensional (surely you know the famous works of
"The Magic Eye", Stereograph produces the same output).


WHY ADVANCED?

Yes, that's an interesting question. I know that there are thousands of SIS
generators available out there. I bought one because I wanted to create
something special - but I was disappointed when I created my first
well-prepared composition. The quality was anything but useful. In the third
dimension (the depth of the image) I was able to see different rough steps
instead of really smooth transitions as expected. I couldn't believe that. I
had purchased a professional program to do a serios job for me. So I took a
pencil, a piece of paper and some time to find an optimized way of processing
stereograms. Stereograph is the result of all my inventions related to this
this problem. I implemented anti-aliasing for more realistic level transitions
and to follow exaclty the height structure that is described in the base image.
I added a zoom feature which has the same effect but is more or less not useful
for stereograms on a computer screen. Additionally I expanded the depth detail
level of 256 levels to 765. If it should be one day necessary to increase this
level again, there is no limit to extend it up to 24 bits (16.7 millions) or
even more.

To learn how to use all these useful features simply read on. :)


HOW TO PUT A PRE-STEREOGRAM INTO THE RENDERER

Before I begin with the explanation for each single flag I want you to notice
that I have only implemented TARGA graphics file i/o functions 'til now. The
output will be EVERYTIME in 24 bit TARGA type 2 (that's really uncompressed).
Also I didn't put in the Huffman-compression code, so there's no support for
other TARGA types than 1, 2, 3, 9, 10 and 11; that's all for now. Feel free to
add your own preferred formats and filters or simply send me a reference
library and I'll see what I can do. But for all the jpeg freaks out there: jpeg
uses a LOSSY compression algorithm that is anything but suitable for high
quality stereograms! Even gif is more useful even if it offers usually only 256
colors. I am looking straight ahead to PNG.

  -b base
     First of all we begin with a file describing the "relief" of our 3d model.
     The base file should contain all information about our object(s). It is a
     simple graphic where the brightness of a pixel defines its individual
     depth. The darker a pixel is, the more far away it will seem to be in the
     final stereogram - the brighter it is, the closer it will be. Usually only
     gray scale images are used to keep this information. As there are only 256
     tones I decided to terminate this limitation. Of course, any gray scale
     image will be enough for a nice stereogram and can be used with
     stereograph. But if you wanna go for real quality (I mean that quality
     that is needed when you want to render a realistic tree and put an ant on
     it) you can use the full bandwidth of 765 levels by using a special color
     map for rendering (POVRAY does a good job - www.povray.org). Internally
     the RGB values of each pixel are added to calculate the depth.

  -t texture
     everybody identifies with a stereogram the beautiful textures that are
     used to produce themselves. A good texture for a good stereogram needs a
     lot of love and details and some know-how or enough intuitive feelings to
     create one. The texture is that what everyone sees when regarding your
     stereogram - even if he cannot get in the third dimensions of your
     composition. Without an attractive texture you won't invite attractive
     visitors for your personal art work. ;)
     Technical note: the width of the texture stands for the maximum depth of
     any steregram and it cannot be greater than the distance of your two
     eyes - otherwise you won't be able to see anything in your stereogram but
     your beautiful great texture. As a hand rule, 100 should work nice for
     stereograms of 640*480 up to 800*600 pixels. Use 110 to 120 for greater
     ones.

     Sorry, there's still no random texture generator implemented yet!

  -o output
     The file where the stereogram is written to. If it exists stereograph
     won't ask you to allow it to overwrite it, it will simply do it.


OPTIONS

  -a anti-aliasing
     describes a value between 1 and 32 that declares how many pixels shall
     be calculated by the renderer virtually for ONE pixel. So 1 is the
     absolute minimum, 4 is predefined. You can calculate easily: physically
     you habe n depth levels, where n is the width of the texture used for
     the stereogram. With the AA feature you now have theoretically a*n levels.
     This feature increases _massively_ the color depth of the output file -
     so always try to keep it in true color modes (24 bits or more). I've
     already converted different stereograms processed with AA (7+) to indexed
     ones and couldn't really feel a loss of 3d quality. It's always your
     decision and your former free disk space or net resources, a compromise
     with quality.

  -z zoom
     based on the same idea as AA and has the same effects but physically
     increases the file size. Here 1 the minimum is predefined. It increases
     the width AND the height of the output stereogram by z - so be very
     careful with your free resources, it could end up in a great colorful
     mess...

     btw, for AA and zoom only integer values are exected.

  -d distance
     describes the distance of your eyes and the virtual glass that is between
     you and your stereogram. Standard is 0.6, feel free to walk backwards up
     to 8.0 steps.

  -x texture_start_x
     where the texture is inserted the first time and where the rendering
     process begins its rounds. standard: 0 (left image border);

  -y texture_start_y
     y offset of the texture. standard: 0 (top);


Care about your screen 'cause of the impressioning effects of stereograph! ;)