rec.autos.simulators

GPL ghost cars

MeatWate

GPL ghost cars

by MeatWate » Thu, 26 Nov 1998 04:00:00

Johan,

this is NOT a place for binaries! By the way, this happens quite often. Have
a look at this, there couldn't be a better example:

http://www.racesimcentral.net/***er/weird.zip

Bart Westr

GPL ghost cars

by Bart Westr » Thu, 26 Nov 1998 04:00:00

My guess is that collision detection is done for the local car only. The
local _predictions_ of the remote cars are involved only if they collide
with the local car.
Two remote cars can be in the same place. You can also see remote cars move
through objects (due to prediction errors). If you'd watch the replays made
on the machines of the cars involved, you would get a different story.

Am I right in thinking that you hosted this race? Most of the time, clients
only see one car behind and four in front. Only if one of the two cars just
passed the other one would you see two cars behind you for a short while
(less than half a second).

Bart


>Hi all,

>Yesterday I was doing a pro short race at Watkins Glen and during the race
I
>saw something happening in my mirrors. After the race I checked the replay
>and saw that Irwin's car drove right THROUGH the car of Siffert! I was
>really surprised by this, since the collision calculation seemed to be so
>accurate. I wonder how this was possible. Does anyone dare to guess?

>I attached a short piece of replay to this post, so you can see for
>yourself. It's best viewed in chase view from Irwins car.

>// Johan

Mike Malon

GPL ghost cars

by Mike Malon » Thu, 26 Nov 1998 04:00:00

GPL AI cars do not have full time collision detection.  This is not a
bug--it is an intentional implementation decision that was made for two
reasons: performance & AI longevity.

phil

GPL ghost cars

by phil » Thu, 26 Nov 1998 04:00:00

perhaps the ai only determines collisions of cars, say, 4 cars in front and
1 or 2 behind?


>> GPL AI cars do not have full time collision detection.  This is not a
>> bug--it is an intentional implementation decision that was made for two
>> reasons: performance & AI longevity.

>Interesting.  When is AI collision detection enabled?  I know I've seen
>crashes with the AI when, believe it or not, I wasn't involved, although
>I was nearby.  At the start of a race at Spa, Surtees and Rodriguez
>locked wheels and took out two other AI cars.

>Thanks,

>Dave Ewing

Mike Malon

GPL ghost cars

by Mike Malon » Thu, 26 Nov 1998 04:00:00

Very roughly: when they feel they have lost control; when mechanical
problems have occurred; when they leave the primary racing surface (might
or might not be fully off track).    It doesn't matter where they are in
relation to player car (they could be on opposite side of track), except
that, as you probably know, not only is the player car always collision
enabled, it can "bless" nearby AI cars to become temporarily collision
enabled with each other.

Inability to brake quickly enough (a common problem for Irwin, e.g.,
depending on the game settings and randomization) is not a loss of control
situation as far as AI is concerned (for longevity reasons, as mentioned)
so the ghosting occurs.

David Ewin

GPL ghost cars

by David Ewin » Thu, 26 Nov 1998 04:00:00


> GPL AI cars do not have full time collision detection.  This is not a
> bug--it is an intentional implementation decision that was made for two
> reasons: performance & AI longevity.

Interesting.  When is AI collision detection enabled?  I know I've seen
crashes with the AI when, believe it or not, I wasn't involved, although
I was nearby.  At the start of a race at Spa, Surtees and Rodriguez
locked wheels and took out two other AI cars.

Thanks,

Dave Ewing


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