[osg-users] Convert .earth file to .osg format

[Robert Osfield]

Hi Steven,

It's probably getting on decade since I last used or did any serious
worked on VPB so can't recall the specific command line options to use
off the top of my head.  So will just provide some general notes that
may help.

It's possible to have osgdem (single process build) and vpbmaster
(multi-process distributed build) using a directory as input rather
than individual files.  Run osgdem -h to get the command line options.
You can generate a single source file from your initial input
parameters and reuse that source file subsequently - this is what is
also used in the distributed build.

I'm afraid I can't help beyond this without sitting down at my
workstation to do some test builds after doing re-learning of the
command line options.

FYI, in the coming months I'll be doing some work on paging in for the
VulkanSceneGraph project and will likely do some work with VPB to get
it to generate native .vsgb rather than .osgb files.  At this point
I'll need to dive back into VPB and re-lean how to use it properly :-)

Robert.