Re: [Spacetrek-users] Fwd: [Vegastrike-devel] Netrek multiplayer

[<st...@bu...>]

Hi,

On Jan 23, 22:51, Alexander Rawass wrote:
> Subject: [Spacetrek-users] Fwd: [Vegastrike-devel] Netrek multiplayer
> Hi,
> =

> did you read this?

oops, I missed this one in the digest. I have some problems to keep up
with my email; there is a spammer who subscribes me to every mailing
list and newsletter he can find. In January alone my anti-spam software
refused 9,600 emails out of 10,000 :-( Therefore I sometimes miss the
real important emails, but that's not by intention, sorry.
 =

> That means, the game is calculated and run on the server, and the clien=
t only
> displays what the server tells them.

That's correct, although in spacetrek several things can be "localized"
such as orbiting a planet or exploding the ship.
 =

> This protocol may be fine for Netrek, and it may work also fine for VS =
in a
> local LAN, but I doubt that this sort of protocol will work over modem =
lines
> or thorugh the internet.
> =

> a) VS will have to transport much more data - more ships, more laser bo=
lts.
> b) The reaction time for the client will be
> lag_from_server_to_client+lag_from_client_to_server, so when the player=
 fires
> a laser, then the client has to send that to th server and then the ser=
ver
> has to send the pos of the new bolt back, and then the player can see t=
he
> bolt.
> c) When the connection to the server hangs, the client will hang.
> =

> =

> Stefan, can you confirm these problems in some way?

Yes, you are right that the protocol is probably to weak for VS.
Netrek is slooow. Usually you fire torpedoes in the direction
where you suspect the ship to be in a few seconds ...

However, much of the code for the protocol was optimized back in the
days when modem lines were used to connect to the Internet. With today's
bandwidth (ISDN, T-DSL) I never had a typical lag like in old days, even
not with distant servers.

And: netrek doesn't need collision detect, see below.

> Spacetrek won't get 'true' 3D?
> =

> I mean, the server sends only 2D coordinates, so you only can display t=
he
> ship and it surroundings in 3D, but you'll play in a 2D area and you ca=
n't
> fly in the 3rd dimension?

Correct. This makes it very easy to port if you just begun to learn
3D like me :-) :-) I have divided the 3rd dimension into four planes:
the upper plane is for text decoration (planet names etc.), the next
plane is for the own ship, the following plane is for all other ships
and the last plane is for planets.

This way, every player sees all other ships flying around slightly
below the own ship (ships can be above each other in 2D). Therefore,
I also don't need collision detect (the server doesn't know this
either).

I still have some problems with the distances between planets and
ships which work well for a 2D window, but result in a "small"
universe where objects seem to be nearer when viewing into the Z
direction than they actually are. If I reduce the ZFAR clipping
plane, planets are culled and then suddenly appear - doesn't look
very realistic.

Even if the system is fast enough to render 15-20 frames per second,
the ships are moving according to the speed at which packets are
received from the server - usually at 5 to 10 fps. I'm currently
thinking about interpolating the position of a ship during the
frames where no packets are being received, but so far it's just
an idea and I don't know whether this helps to get smoother
movement. Another alternative is to hack the server and change
the coordinate system and also the resolution at which ships
move through the space. But this would break compatibility with
all other brands of netrek servers and so far I would like to
retain that compatibility, at least as long as I have no other
players in a pure spacetrek server (just kidding :-)

Best whishes
Stefan



-- =

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