Re: [Flightgear-devel] Terrasync for WS3.0

[James T. <ja...@fl...>]

> On 8 Jan 2024, at 16:56, Stuart Buchanan <stu...@gm...> wrote:
> 
> On Mon, Jan 8, 2024 at 4:04 PM James Turner wrote:
>> 
>> 
>>> On 8 Jan 2024, at 15:17, merspieler <mer...@al... <mailto:mer...@al...>> wrote:
>>> 
>>> Also (iirc James mentioned that this might be possible) what
>>> about loading the tgx/tgz files directly instead of unpacking
>>> them onto disk?
>>> Would save me from doubling the data, cause I then don't have
>>> to have it once packed for the mirror and once unpacked for use.
>>> Instead I could, just like with ws2.0 terrasync use the same
>>> thing for both.
>> 
>> It’s possible with some dev effort : easier than the fully general case (Aircraft / FGData from compressed sources) but not trivial unfortunately either. We need to use the OSG Archive stuff to tell osgDB about our compressed files, when someone looks for a path which might be inside one.
> 
> This (compression) might be easier than it looks if we use the osg archive format directly rather than .tgz files.  
> 

I would absolutely avoid this like the plague, because then we are tied to .osga going forward, which I think will cause us other problems. And in general when working with any compressed archive format, being able to inspect / create / extract it using standard command line tools on any machine is a tremendous benefit.

We already have good archive support working for TerraSYnc, and the osgDB::Archive API will let us support .zip or .txz or whatever we need, so if we use do that we are data-compatible forwards and backwards, only a client-side change.

Kind regards,
James