VRML - question for Mufti

Author

question for Mufti

boris

2004-01-20, 5:29 am

Not long ago you posted link for white_dune software. I downloaded it, and I
find it very convenient to work with. All except one thing. I noticed when I
treat vrml files made by other programs with white_dune, they double their
size after such treatment, even if it is not so big changes. I checked the
code of both files, I must confine files that come under white_dune are
clearer, and easier to follow and control, but besides it code itself is the
same, and size is significantly larger.

I would much appreciate if you would like to explain where is that
difference come from.

Joerg Scheurich aka MUFTI

2004-01-20, 9:30 am

> treat vrml files made by other programs with white_dune, they double their

quote:

> size after such treatment, even if it is not so big changes.

....

quote:

> I would much appreciate if you would like to explain where is that
> difference come from.

white_dune is not intented as a VRML compression tool (yet).

Currently it's output is more like the output of a pretty printer, it
do much indentation.

Transform
{
children
[
Shape
{
appearance Appearance
{
material Material
{
}
}
geometry Cone
{
}
}
]
}

Additionally, the distributed dune versions do this "pascal" like
indentation, instead of the "k&r" like indentation

Transform {
children [
Shape {
appearance Appearance {
material Material {
}
}
geometry Cone {
}
}
]
}

you would get, if you would use a white_dune version compiled
(under Linux/UNIX/MacOSX) with

./configure --with-krlikeindent && make

(you may need

./configure --with-krlikeindent --with-buginlesstif && make

if you do not have a "real" motif as on a SGI IRIX machine)

If you recompile white_dune on M$Windows, you need to change the
file src/config.h after running the configuration batchfiles.
You must change the lines

/* Define if you want Kernigan/Richie like indent */
/* #undef HAVE_KR_LIKE_INDENT */

to

/* Define if you want Kernigan/Richie like indent */
#define HAVE_KR_LIKE_INDENT 1

and then continue with clicking to "dune.dsw" (see the INSTALL file
for instructions to recompile white_dune under Linux/UNIX/MacOSX
and M$Windows).

Of cause, this should be a runtime option, not a compiletime option,
but a lot of people currently ask for very more important problems in
white_dune.

If this is important for you, white_dune is a Open Source software:
you may build your private version.
If you build a version with a runtime option to select indention,
and decide to public it, i will integrate the changes in the offical
white_dune version (the license of most of the code in white_dune
require to public the sources to the same users as the binary is publiced
to).

Another problem is number size. Cause of the requirements of the
"save before crash" feature on some systems white_dune use a simple
method to write out numbers. This method print floating point numbers
with too much numbers after the comma in most circumstances.

On long range we need a additional more intelligent method to write
numbers in a none emercency sitution, cause the current emercency write method
is rather slow, in particular when you write to M$Windows network drives 8-(

Another problem is missing gzip compression.

I think, none of this problems is important enough to stop the
fighting with the other problems now.
Especially because other Open Source VRML compression/optimization tools like
chisel/webchisel

http://ovrt.nist.gov/chisel.html

already exist.

In cases as size really matters, please use something like chisel to
improve the output of white_dune.

so long
MUFTI
--
Dies mag auf Windows 3.1 hinter ihnen versteckt werden.
(aus einem Softwarehandbuch)