[opendemo-devel] plan for OpenDemo editor

[Dr. U. G. <Uwe...@ph...>]

Hello!

I intend to increase OpenDemo usage a bit more.

For this I'll write a very simple demo editor over the xmas holiday. The most
important thing for such an editor is a preview window, where Q3A directly
plays back, what I just edited (or where I moved the timeline slider). Thus we
need to feed into the OpenDemo playback mode a continous stream of data
calculated by another program. The idea is to use a named pipe instead of a
plain file. But now the problems start: we can't rewind a named pipe and we
don't know the amount of data at the start at all.

I have no idea, if Q3A can even read from a named pipe, as it has no size to
begin with. To check this out I committed today and yesterday a small change
to switch off the ZLIB code (at compile time and at runtime). The runtime
switch off already works. The compile time switch off is not tested yet.

The next step is to remove optionally (with a new console variable) all tests
on the file end (comparisons with stream->len). Thus odfread() may block but
the external program will feed in always new data anyway. When these
comparisons are gone, I'll try 'cat odfile.xml > pipe.odq3a' and let Q3A replay
'pipe.odq3a'. If it works, we can continue with the actual work of the editor.
If it does not work, we can always fall back to native shared libraries and
let the C library read from the named pipe.

What is the state of named pipe support in Windows? Is there finally an
equivalent of the standard >20 years old 'mkfifo' command?

For reference, the whole idea is a direct replica of the interactive mode of
the demcut program (part of the LMPC project). Quake1 had no problem reading
from a named pipe (and I even wrote a PerlTk front-end for demcut back then).
Let's hope the best.

Bye, Uwe