[sldev] Snowglobe on OpenSim grids

[Carlo Wood]

On Sat, Dec 05, 2009 at 04:30:10PM -0800, Suzy Deffeyes wrote:
> If the code defaults to the existing hardcoded amazon behavior if a  
> cap to map tiles is not returned, then it doesn't require a LL  
> protocol change.

There will be a time that not all OTHER implementations (ie opensim)
have implemented this; in which case the cap will fail.

In that case we want to fall back to the OLD way maps worked,
because that is what works on opensim, at least - on opensim.

Hence, this would require "detection" of on which network
we are, and then adjust the "protocol" as required...

I just wrote a long post about this horror (believe, it will
happen again and again and again and the list of this type
of things will only get LONGER and LONGER!).

What we need, from the very start, is a good protocol
negotiation sheme added to VWRAP (the new name for OGP).

The protocol negotion sheme that I have proposed would
make it clear what the base protocol is (the mandatory
features so to say), as each server implementation gets
it's own label (ie, LindenLab and OpenSim (as well as
version numbers of course)). Then you could indeed say:

Hey, opensim doesn't offer the feature "NewMap", so
we use the old style map. And, hey, LindenLab doesn't
offer the feature "NewMapURL", so we just use the S3
url as fall back (for the mandatory "NewMap" feature).

Also, "NewMap" is really optional at the moment (the
1.23 viewers don't use it)... If the protocol negotiation
had already been in place, then LL would have added
an optional "NewMap" feature, with documentation, at
the same time that it became available. The 1.23 viewer
would not have known what it was and wouldn't use it,
snowglobe would and would use it. THEN, on opensim,
snowglobe would see that there isn't an optional
"NewMap" feature and would NOT use the new map style.

This demonstrates the power, and need, for protocol
negotiation.

At some later date, LL would add support for the new
map also to the official viewers and make the feature
mandatory (so that everyone with a client that doesn't
support it has to upgrade). With the protocol negotiation
that I proposed, the whole "NewMap" option would disappear
from the actual negotiation (the documentation would
still be there though, on the net ;), as if it had
been a part of the protocol like everything else
mandatory (ie, support for teleporting).

-- 
Carlo Wood <carlo at alinoe.com>