Physics [split from network thread]

[stenyak]

are you saying the CPUs are too slow to compute the physic for several cars ?
what about AIs then ? (I heard we have AIs but I don't know how they work :lol: :oops: )

Well, i don't know what's the CPU usage for physics in vDrift (check with a profiler); but i do know of cases where physics is too cpu-hungry.
For example, if you know GPL (Grand Prix Legends, not the license)... the first runnable version took 30 minutes to run a single second of physics. Once it was optimized to run realtime, it was decided to use faked AI physics.
It's just an exageration, but keep in mind it may happen in some way. Take a profiler and do some checks. Remember that we're not talking about simply computing several cars physics, but about computing several cars physics of the last couple tenths of second (due to lag).

Maybe current Vamos physics are simple/optimized enough to run all of that with no problems, i don't know (it probably is), but i can tell that my un-optimized physics in Motorsport do not allow more than 6 cars at once on screen, and most of the problem is physics.
So just keep that in mind; do not assume things before coding all the multiplayer thing

if you have your client have updated positions/speeds whenever the server wants, you may easily end up losing control of the car because you're suddenly in a 90º drift, while you expected to be gripping nicely through the corner apex

I don't see the point of receiving anything from the server for it's own car (except in case of a collision of course)

I meant the other cars (of course you have your own data already).
If you only send car chassis data, it may look very weird during the race, and most importantly during replays. RBR (Richard Burns Rally) had a bug in its first release, the front wheels didn't rotate in replays, and it was very noticeable.

If you want to save some bandwidth, the wheels positions (not rotations) could be "guessed" running some simple physics, like a ray-mesh collision detection, if you know the suspension travel. Most of the times it should look right (except on car jumps, which i think you only have at the nordschleife ).