I am looking into a multiplayer game for GBA,DS & Wii. Now, the problem as I see it is that in Japan & N.America, TVs run at 60Hz (so do the hand-helds) but in Europe they run at 50Hz. How the devil do you get multiplayert between them? I mean, most modern TVs will accept a sync from the box so yes, they will swap to 60Hz, but is this implicit in the design of the Wii?
Ta,
P-)
Je Suis Marxiste, tendante Graucho.
It would make the most sense for online play to be arbitrated in software, and for competitive games in a way thats fair for any region. As long as the game speed is the same (which should happen in any localization) regardless of the actual frame rate, the games can be synchronized. I don't get why you're getting into actual TVs, do you mean when you play with someone in NTSC land your TV switches to 60Hz?
Last edited by Calpis; 07-26-2008 at 11:06 PM.
Exactly, you do not necessarily need to be running your update (physics, AI, input, etc.) routines at the same rate as your draw functions.
PouncingKitten Games
Xbox 360 - Glide, Bingo Party, Poker Night, O.C.D.
Flash - BunnyRun, Tic-Tac-Poker
While I agree with your logic, i you have a game running in 1 frame (50Hz Wii, 60Hz DS) then the DS is going to drop 1 frame in 6. I cannot help but think that somewhere the Wii documents will have a solution.
Also, coding for different frame-rates is a total pain in the ass. I have done it before, but boy, the trouble I had. I've not actually seen a DS<->Wii game playing. I suspect that seeing it in action would tell me a lot...
Je Suis Marxiste, tendante Graucho.
I haven't had the chance to program on the DS or Wii, so I cannot account for how they handle locked timesteps. However, if you code towards an unlocked timestep using variable elapsed time intervals instead of using a fixed timestep, then it wouldn't matter what your screen refresh rate is. Sure, it requires a little bit more time interval tracking for physics and AI calculations, but it is certainly common. Just think about having to deal with multiple refresh rates on the PC (60, 72, 120, etc). As far as synching between platforms, if you use a bit of speculation/prediction, you can get away with network updates at a longer interval, such as on even second intervals.
PouncingKitten Games
Xbox 360 - Glide, Bingo Party, Poker Night, O.C.D.
Flash - BunnyRun, Tic-Tac-Poker
Alot of network games don't allow people running in pal & ntsc to play against each other. If you try then it will probably look jerky.Originally Posted by Piglet
pal & ntsc tv standards do not apply to DS and PSP iirc.
they are all the same in every region.
PAL TV's run at 50 Hz but you can of course run them at 60 Hz. For example, in Dreamcast games, if you wanted to play against Japanese or American players you had to play at 60 Hz, if your TV didn't handle it you we're forced to play against PAL dudes.
Quite a games now in PAL-land ask for 60Hz only (no option of running in 50Hz), so I think you could get away with it.
I'm thinking that these days, there will be only a tiny number of PAL tv's that won't take an external Vsync.
Updating the logic for a 2D, 60Hz game won't really work since what was being displayed by each screen wouldn't be the same. 3D, not-in-a-frame games certainly do that.
Of course, even IF your supposedly running at the same speed, hand-held machines use a clock. Clocks are not accurate so each machine runs at a slightly different speed. The way I got around this on the GBA was to wait for the slowest machine. It did drop the occasional frame, but not so much that it was noticable...
Je Suis Marxiste, tendante Graucho.
All tv's take an external vsync, otherwise they don't know when the frame starts and ends. However old tv's couldn't cope with the interval between the vsync from being different to your local tv standard.
An old TV being 15+ years I'd assume, as all the TVs I've encountered including my cheap Sanyo one from around 10 years ago are happy showing 60Hz stuff. NTSC... now that's a different question.
I don't think that 60Hz automatically means NTSC. One is a refresh rate, the other an encoding technique. Old OLD really OOOLLLD TVs use the mains AC value to refresh the screen (I assume there must have been some kind of stabalisation since it's rarely exactly 50/60Hz). I think most things in the last 20 years take the sync from the input so it SHOULD be OK.... hope so in any case.
As I said before, how do you sync an 'in a frame' 2D action game between 50 & 60Hz. I mean, you cannot do the refresh & display logic seperatly like you can in 3D...
Je Suis Marxiste, tendante Graucho.
Vertical hold setting?
Well, run everything at 300Hz and you'll be fine. :lol:As I said before, how do you sync an 'in a frame' 2D action game between 50 & 60Hz. I mean, you cannot do the refresh & display logic seperatly like you can in 3D...
Honestly, I still do not see a gamebreaking problem here. So what if your logic is running at two different speeds as long as the algorithms allow for a flexible timestep. Hell, you don't even have to have a full variable time step if you want to go through and code two sets of "update" variables for your physics, AI, etc. The only (simplified) real concern with multiplayer games is syncing up the data, and that you can do on "matching" boundries, say every 5/6 frames (50/60 Hz respectively).
PouncingKitten Games
Xbox 360 - Glide, Bingo Party, Poker Night, O.C.D.
Flash - BunnyRun, Tic-Tac-Poker
:nod: 300Hz it is :dance:
Je Suis Marxiste, tendante Graucho.
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