Re: [GD-General] time

[Mike W. <mi...@ge...>]

for multiplayer games like counter-strike or bf9142, i think that the=20
engine completely 'restarts itself' on every map change to help avoid=20
these types of errors.

i recall a bug in quake that would crash it every 'x' hours on clockwork=20
if left running in 'demo mode' for example...

for a massively multiplayer game though you would want to use something=20
more robust indeed.

other than relying on the system clock itself (or a system-specific=20
high-performance multi-media timer), i'm not sure how i'd approach this.

we use the windows internal clock for our own timing, and have routines=20
that check to see if we've 'fallen off the track' at any point, if so,=20
we do a sync between our internal game 'clock' and the windows system clo=
ck.

for multiplayer games, you may want all games (client or server) to rely=20
on the 'master server' clock possibly, not on a frame-by-frame basis,=20
but on a larger 'sync' basis, where you can make sure that all clients=20
are synced to the same timestamp?

i'm not sure how else you'd approach this, aside from just forcing the=20
clients to sync to the server's time, whatever it happens to=20
be...clients would add or drop frames as neceessary to stay in sync...

mike w
www.gekidodesigns.com

Brett Bibby wrote:
> Howdy, I have been wrestling with time in my engine for some time now
> (no pun intended). I wondered how other people are handling time? Our
> game engine is specifically designed for PS2/Gcn, but it runs under
> Windows too. Specifically...
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> What are the different components that people are using? We currently
> have a single 32-bit time variable initialized to zero at startup and
> that's it. Each frame we either count v-blanks, use system
> ticks/timers or OS facilities custom for each platform to increment
> the global time value, usually stored in microseconds and rounded up
> to millisecond resolution for use in the engine. Works well and I
> have done this for every game engine I have developed so far.
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> Feels like a change may be warranted though as online gaming becomes
> more popular, since if the game was to run for many days it would
> overflow and timestamping may be problematic. So now I'm thinking of
> adding a time struct (different from ANSI C though) whereby we store
> the year, month, day, hour and minute, and second and also a
> conversion struct that says how many mins->hour->day->month->year so
> we can convert "real" time into game time. I can pack this into
> 64-bits, but then again a simple 64-bit timer using the old way to
> simply count ticks would also eliminate the overflow problem anyway
> and so I'm questioning the right thing to do. Also, I hoping to be
> able to use absolute time for certain things where we used to use
> delta times. What are people using for timestamps for online games?
> Does each game session reset the server session time to prevent
> eventual overflow? Or is a more robust timing mechanism used? Are
> people using microseconds? milliseconds?
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> Thanks, Brett
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