Gran Turismo 4 delayed (again)

[Cryect]

How does Germany become DE? Allemagne?

Because Germany is Bundesrepublik Deutschland its not Germany except for English speakers. The real question is how did Deutschland become Germany (could look it up the word history but I'm lazy).

 

[randycat99]

Phil know his stuff here. IMo, any game where the player is moving at significant speed and change direction between frames, will require some sort of prediction to keep the error correction to a minimum.

I'd have to disagree here with Phil. All you need to pass on the relevant data with a bit extra to keep the physics honest between frames is a positional/angular data and acceleration vector (maybe throw-in velocity vector if you want to really be robust against the data update jitters ). You don't send raw state data (presumably the input to a simulation enghine) across a communication line. You send the end result. You do the brunt of the computations local. Sending it over a link just so it will be calculated local somewhere else will not make the physics any more accurate.

Now, if you really want to split hairs, you could say that passing reaction forces/moments, in addition to the above mentioned data, would be useful to cover inter-car "contact" (i.e., collisions). However, it is equally plausible that even this could still be finagled locally, given the positional/angular data of opponent cars and assumed surface boundaries.

 

[Freak'n Big Panda]

yea I'd have to agree with randy cat here. I can see no real reason that any ps2 would need the raw data to provide a good online experience. posistion, aceleration and velocity should be suffienent I think. Phil mentioned engine noice but rpm is just another way of saying speed, you can calculate speed as long as you know the gear ratios and current gear of any given car. So uploading current rpm would be pretty useless IMO. I guess if you wanted to know if the tires are squealing or not you would need the coificient of frition between the tires and the road plus the wieght of the car to calculate the force of friction to see if the car will keep its path or not. If not the tires are squealing. Still though I really don't see how 1mbps could be needed... I mean thats 125KBps... quite a bit of data I think. CSS only uls about 3KBps even in big battles And yea 1mbps is pretty rare in canada, I've got a quite a good service compared to whats tons of other ppl I know have and its only 6mbps down 600kbps up.

 

[Phil]

I'd have to disagree here with Phil.

Heh, I was just speculating over possible issues and why high bandwidth could be a requirement.

You don't send raw state data (presumably the input to a simulation enghine) across a communication line. You send the end result. You do the brunt of the computations local.

I was assuming the raw state data would be smaller in size than the end result which would hold more information than simply positional/angular data and a acceleration vector? Especially given that a lot of the raw state data is probably being used to show what's optically happening with the car as well as sounds (squeeking tires, engine rev) and not just for handling-aspects of the car. I assume some of the raw state data would need to be used to show what the car is doing at the given position

 

[randycat99]

Most of that can be inferred right from the basic positional/velocity/acceleration data. I guess you can throw in engine speed and gear selection, so you could get the engine sound right for opponent cars. You don't need to, however. The engine speed and gear selection could just as easily be finagled locally via AI in response to the positional/velocity/acceleration data. It may not be absolutely true to "reality", but who is to really know better (unless your remote opponents are not so remote and are actually playing right beside you on their own TV sets)...as long as the resulting experience is believable from a visual or aural standpoint.

The engine sound issue does illustrate the scale of data that should be sent and that which should be kept local. You don't send streaming audio of the engine sound over the comm link- that would be gratuitously wasteful of bandwidth. You send the bits of data (engine rpm and gear selection) so that the sound can be reconstructed locally. In the end, I don't see this data adding up to requiring anything along the lines of Mbit/s. If you are needing much more than a few kbit/s, then something is seriously wrong.

 

[-tkf-]

Most important thing in a game like this is latency. If the player has to feel the game is solid everything has to react like he is used to in Offline mode.

But compared to online games like FPS games i think that GT4 is way easier.

As i see it you only need to know/send 8 z,x,y points from/to the clients for every player, the wheels and the suspension point on the chasis and some general info like RPM, Driver Figure, etc. Compared to FPS games where countless objects are predicted it shouldn't be a problem. And the CPU doesn't even have to work on AI.

 

[Phil]

The engine sound issue does illustrate the scale of data that should be sent and that which should be kept local. You don't send streaming audio of the engine sound over the comm link- that would be gratuitously wasteful of bandwidth.

...nor did I (or anyone else) propose such an idea - in fact, I said the same thing in my previous post! I just took your idea of sending over bits of data like the engine rpm and gear selection one bit further by assuming that more data is sent over to show what the car is doing at its position. Personally, I think ERPs closest in his assumption that online play wasn't included into the game-mechanics when it was at its design phases and now the team is having trouble implementing it efficiantly into a 'finished/working' game-engine.

I also think that the assumption of 1Mbps requirement is a bit far fetched, especially knowing that there is some kind of server where things are centralized.,

 

[randycat99]

Fair enough. Those remarks were not directed at you specifically, btw. I just wanted to draw some lines in the sand before we got too far off on some kick that massive amounts of data will need to be transferred to make online play work in this game.