gamedevlists-general

[GD-General] time

[Brett B. <res...@ga...>]

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...

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.

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?

Thanks,
Brett

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...
>=20
> 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.
>=20
> 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?
>=20
> Thanks, Brett
>=20
>=20
> ------------------------------------------------------- SF.Net is
> sponsored by: Speed Start Your Linux Apps Now. Build and deploy apps
> & Web services for Linux with a free DVD software kit from IBM. Click
> Now! http://ads.osdn.com/?ad_id=1356&alloc_id438&op=CCk=20
> _______________________________________________ Gamedevlists-general
> mailing list Gam...@li...=20
> https://lists.sourceforge.net/lists/listinfo/gamedevlists-general=20
> Archives: http://sourceforge.net/mailarchive/forum.php?forum_idU7
>=20
>=20

RE: [GD-General] time

[Tom S. <to...@pi...>]

  http://www.dallasigda.org/notes.htm

  You'll see a document called "Time in games" which are notes on a
presentation done by Squirrel Eiserloh.  It covers a lot about time in
Win32 and the different methods he's used to tackle it.  People may find
it helpful.

  Tom


> -----Original Message-----
> From: gam...@li...=20
> [mailto:gam...@li...] On=20
> Behalf Of Brett Bibby
> Sent: Friday, February 20, 2004 8:59 PM
> To: Gam...@li...
> Subject: [GD-General] time
>=20
>=20
> Howdy,
> I have been wrestling with time in my engine for some time=20
> now (no pun intended). I wondered how other people are=20
> handling time? Our game engine is specifically designed for=20
> PS2/Gcn, but it runs under Windows too. Specifically...
>=20
> What are the different components that people are using? We=20
> currently have a single 32-bit time variable initialized to=20
> zero at startup and that's it. Each frame we either count=20
> v-blanks, use system ticks/timers or OS facilities custom for=20
> each platform to increment the global time value, usually=20
> stored in microseconds and rounded up to millisecond=20
> resolution for use in the engine. Works well and I have done=20
> this for every game engine I have developed so far.
>=20
> Feels like a change may be warranted though as online gaming=20
> becomes more popular, since if the game was to run for many=20
> days it would overflow and timestamping may be problematic.=20
> So now I'm thinking of adding a time struct (different from=20
> ANSI C though) whereby we store the year, month, day, hour=20
> and minute, and second and also a conversion struct that says=20
> how many mins->hour->day->month->year so we can convert=20
> "real" time into game time. I can pack this into 64-bits, but=20
> then again a simple 64-bit timer using the old way to simply=20
> count ticks would also eliminate the overflow problem anyway=20
> and so I'm questioning the right thing to do. Also, I hoping=20
> to be able to use absolute time for certain things where we=20
> used to use delta times. What are people using for timestamps=20
> for online games? Does each game session reset the server=20
> session time to prevent eventual overflow? Or is a more=20
> robust timing mechanism used? Are  people using microseconds?=20
> milliseconds?
>=20
> Thanks,
> Brett
>=20
>=20
> -------------------------------------------------------
> SF.Net is sponsored by: Speed Start Your Linux Apps Now.
> Build and deploy apps & Web services for Linux with
> a free DVD software kit from IBM. Click Now!=20
> http://ads.osdn.com/?ad_id=1356&alloc_id438> &op=3Dick
>=20
> _______________________________________________
>=20
> Gamedevlists-general mailing list=20
> Gam...@li...
> https://lists.sourceforge.net/lists/listinfo/gamedevlists-general
> Archives: http://sourceforge.net/mailarchive/forum.php?forum_idU7
>=20
>=20

Re: [GD-General] time

[Brett B. <res...@ga...>]

That's a great document and covers pretty much everything we discussed =
internally, nice reference! The doc's discussion of different =
resolutions combined with independent running (some time keeps running =
even when paused) is something I hadn't thought of and I will look into =
that. Meanwhile, anybody doing an online game care to comment how you =
handle time? As a player of MMORPG I always am wondering how they =
timestamp and integrate time into their engines, and if feasible I would =
like to make sure we can support arbitrary lengths of time too.
Brett

----- Original Message -----=20
From: "Tom Spilman" <to...@pi...>
To: <gam...@li...>
Sent: Saturday, February 21, 2004 11:14 AM
Subject: RE: [GD-General] time


>=20
>   http://www.dallasigda.org/notes.htm
>=20
>   You'll see a document called "Time in games" which are notes on a
> presentation done by Squirrel Eiserloh.  It covers a lot about time in
> Win32 and the different methods he's used to tackle it.  People may =
find
> it helpful.
>=20
>   Tom
>=20
>=20
> > -----Original Message-----
> > From: gam...@li...=20
> > [mailto:gam...@li...] On=20
> > Behalf Of Brett Bibby
> > Sent: Friday, February 20, 2004 8:59 PM
> > To: Gam...@li...
> > Subject: [GD-General] time
> >=20
> >=20
> > Howdy,
> > I have been wrestling with time in my engine for some time=20
> > now (no pun intended). I wondered how other people are=20
> > handling time? Our game engine is specifically designed for=20
> > PS2/Gcn, but it runs under Windows too. Specifically...
> >=20
> > What are the different components that people are using? We=20
> > currently have a single 32-bit time variable initialized to=20
> > zero at startup and that's it. Each frame we either count=20
> > v-blanks, use system ticks/timers or OS facilities custom for=20
> > each platform to increment the global time value, usually=20
> > stored in microseconds and rounded up to millisecond=20
> > resolution for use in the engine. Works well and I have done=20
> > this for every game engine I have developed so far.
> >=20
> > Feels like a change may be warranted though as online gaming=20
> > becomes more popular, since if the game was to run for many=20
> > days it would overflow and timestamping may be problematic.=20
> > So now I'm thinking of adding a time struct (different from=20
> > ANSI C though) whereby we store the year, month, day, hour=20
> > and minute, and second and also a conversion struct that says=20
> > how many mins->hour->day->month->year so we can convert=20
> > "real" time into game time. I can pack this into 64-bits, but=20
> > then again a simple 64-bit timer using the old way to simply=20
> > count ticks would also eliminate the overflow problem anyway=20
> > and so I'm questioning the right thing to do. Also, I hoping=20
> > to be able to use absolute time for certain things where we=20
> > used to use delta times. What are people using for timestamps=20
> > for online games? Does each game session reset the server=20
> > session time to prevent eventual overflow? Or is a more=20
> > robust timing mechanism used? Are  people using microseconds?=20
> > milliseconds?
> >=20
> > Thanks,
> > Brett
> >=20
> >=20
> > -------------------------------------------------------
> > SF.Net is sponsored by: Speed Start Your Linux Apps Now.
> > Build and deploy apps & Web services for Linux with
> > a free DVD software kit from IBM. Click Now!=20
> > http://ads.osdn.com/?ad_id=1356&alloc_id438> &op=3Dick
> >=20
> > _______________________________________________
> >=20
> > Gamedevlists-general mailing list=20
> > Gam...@li...
> > https://lists.sourceforge.net/lists/listinfo/gamedevlists-general
> > Archives: http://sourceforge.net/mailarchive/forum.php?forum_idU7
> >=20
> >=20
>=20
>=20
>=20
> -------------------------------------------------------
> SF.Net is sponsored by: Speed Start Your Linux Apps Now.
> Build and deploy apps & Web services for Linux with
> a free DVD software kit from IBM. Click Now!
> http://ads.osdn.com/?ad_id=1356&alloc_id438&op=CCk
> _______________________________________________
> Gamedevlists-general mailing list
> Gam...@li...
> https://lists.sourceforge.net/lists/listinfo/gamedevlists-general
> Archives:
> http://sourceforge.net/mailarchive/forum.php?forum_idU7

Re: [GD-General] time

[Brett B. <res...@ga...>]

Forgot to mention another doc. This one at =
http://www.codeproject.com/datetime/dstbugs.asp is a really nice =
introduciton to higher level timekeeping and it helped me wade through =
some of the issues, especially wrt integrating global timestamped stuff.
Brett

----- Original Message -----=20
From: "Brett Bibby" <res...@ga...>
To: <gam...@li...>
Sent: Saturday, February 21, 2004 12:06 PM
Subject: Re: [GD-General] time


> That's a great document and covers pretty much everything we discussed =
internally, nice reference! The doc's discussion of different =
resolutions combined with independent running (some time keeps running =
even when paused) is something I hadn't thought of and I will look into =
that. Meanwhile, anybody doing an online game care to comment how you =
handle time? As a player of MMORPG I always am wondering how they =
timestamp and integrate time into their engines, and if feasible I would =
like to make sure we can support arbitrary lengths of time too.
> Brett
>=20
> ----- Original Message -----=20
> From: "Tom Spilman" <to...@pi...>
> To: <gam...@li...>
> Sent: Saturday, February 21, 2004 11:14 AM
> Subject: RE: [GD-General] time
>=20
>=20
> >=20
> >   http://www.dallasigda.org/notes.htm
> >=20
> >   You'll see a document called "Time in games" which are notes on a
> > presentation done by Squirrel Eiserloh.  It covers a lot about time =
in
> > Win32 and the different methods he's used to tackle it.  People may =
find
> > it helpful.
> >=20
> >   Tom
> >=20
> >=20
> > > -----Original Message-----
> > > From: gam...@li...=20
> > > [mailto:gam...@li...] On=20
> > > Behalf Of Brett Bibby
> > > Sent: Friday, February 20, 2004 8:59 PM
> > > To: Gam...@li...
> > > Subject: [GD-General] time
> > >=20
> > >=20
> > > Howdy,
> > > I have been wrestling with time in my engine for some time=20
> > > now (no pun intended). I wondered how other people are=20
> > > handling time? Our game engine is specifically designed for=20
> > > PS2/Gcn, but it runs under Windows too. Specifically...
> > >=20
> > > What are the different components that people are using? We=20
> > > currently have a single 32-bit time variable initialized to=20
> > > zero at startup and that's it. Each frame we either count=20
> > > v-blanks, use system ticks/timers or OS facilities custom for=20
> > > each platform to increment the global time value, usually=20
> > > stored in microseconds and rounded up to millisecond=20
> > > resolution for use in the engine. Works well and I have done=20
> > > this for every game engine I have developed so far.
> > >=20
> > > Feels like a change may be warranted though as online gaming=20
> > > becomes more popular, since if the game was to run for many=20
> > > days it would overflow and timestamping may be problematic.=20
> > > So now I'm thinking of adding a time struct (different from=20
> > > ANSI C though) whereby we store the year, month, day, hour=20
> > > and minute, and second and also a conversion struct that says=20
> > > how many mins->hour->day->month->year so we can convert=20
> > > "real" time into game time. I can pack this into 64-bits, but=20
> > > then again a simple 64-bit timer using the old way to simply=20
> > > count ticks would also eliminate the overflow problem anyway=20
> > > and so I'm questioning the right thing to do. Also, I hoping=20
> > > to be able to use absolute time for certain things where we=20
> > > used to use delta times. What are people using for timestamps=20
> > > for online games? Does each game session reset the server=20
> > > session time to prevent eventual overflow? Or is a more=20
> > > robust timing mechanism used? Are  people using microseconds?=20
> > > milliseconds?
> > >=20
> > > Thanks,
> > > Brett
> > >=20
> > >=20
> > > -------------------------------------------------------
> > > SF.Net is sponsored by: Speed Start Your Linux Apps Now.
> > > Build and deploy apps & Web services for Linux with
> > > a free DVD software kit from IBM. Click Now!=20
> > > http://ads.osdn.com/?ad_id=1356&alloc_id438> &op=3Dick
> > >=20
> > > _______________________________________________
> > >=20
> > > Gamedevlists-general mailing list=20
> > > Gam...@li...
> > > https://lists.sourceforge.net/lists/listinfo/gamedevlists-general
> > > Archives: http://sourceforge.net/mailarchive/forum.php?forum_idU7
> > >=20
> > >=20
> >=20
> >=20
> >=20
> > -------------------------------------------------------
> > SF.Net is sponsored by: Speed Start Your Linux Apps Now.
> > Build and deploy apps & Web services for Linux with
> > a free DVD software kit from IBM. Click Now!
> > http://ads.osdn.com/?ad_id=1356&alloc_id438&op=CCk
> > _______________________________________________
> > Gamedevlists-general mailing list
> > Gam...@li...
> > https://lists.sourceforge.net/lists/listinfo/gamedevlists-general
> > Archives:
> > http://sourceforge.net/mailarchive/forum.php?forum_idU7
>=20
>=20
> -------------------------------------------------------
> SF.Net is sponsored by: Speed Start Your Linux Apps Now.
> Build and deploy apps & Web services for Linux with
> a free DVD software kit from IBM. Click Now!
> http://ads.osdn.com/?ad_id=1356&alloc_id438&op=CCk
> _______________________________________________
> Gamedevlists-general mailing list
> Gam...@li...
> https://lists.sourceforge.net/lists/listinfo/gamedevlists-general
> Archives:
> http://sourceforge.net/mailarchive/forum.php?forum_idU7