5 ms·

Could you expand on the ROM game commands bit? Does it mean that all actions are serialized?

by apkallum 6y ago

tantalor 6y ago
It's a networked game... how else could it work?
- jldugger 6y ago
  I just don't know what a 'ROM game command' is. Seems more likely it would be controller inputs to one person's emulator? Or perhaps everyone has an emulator and the inputs are simply shared.
  - read_if_gay_ 6y ago
    To me it seems like just a somewhat awkward way to phrase exactly what you think it means.
  - JoeOfTexas 6y ago
    These things usually work by syncing the emulator clocks between clients, and then sending player inputs over the network along with the data to sync.
  - sktrdie 6y ago
    It’s probably really simple: if you normally load a ROM game and start a multiplayer game you control all the other players input. This simply goes next step and makes other inputs be controlled by other players.
    - mrmonkeyman 6y ago
      That has nothing to do with "ROM".
Vel0cityX 6y ago
> ROM game commands This phrase doesn't mean anything. The game list includes games that do not support PlayStation Link Cable, so this has to implement netplay the same way other emulators do: Both host and client emulate the game in sync, exchanging controller input Edit: Seems like I was wrong about the latter, it runs the emulator on the host only, who sends video/audio from clients (and they send inputs).
- danbolt 6y ago
  I’d be curious to see how feasible a rollback-based implementation would be for emulating the game.
  - ohyeshedid 6y ago
    If you're referring to constantly sending save states back and forth, some emulators work this way currently. If I'm not mistaken, RetroArch's networking functions in that way.
    - reitzensteinm 6y ago
      Rollback networking is essentially event sourcing. Game states are immutable, and new game states are derived from adding inputs (events). You keep the last dozen game states around in memory, and if you receive an input from the past, you rewind to the last game state prior, add it to your input stream, and fast forward to the present. It has the same base advantages and drawbacks as RTS networking - the core logic is written as though the game is single player, and complexity can be scaled arbitrarily without bloating bandwidth requirements. But in addition, you get the benefit of zero input latency (play a multiplayer RTS game and send a unit around - they won't move for 200ms or so), and the drawback of an absolute clusterfuck time rewind debugging madness if any inadvertent mutation of your immutable data happens. The reason you do rollback with something like this is it gives you zero latency, and you can retrofit it on to an emulator without changing any game code just by using memcpy() on the game state. Source: I've developed about a dozen titles using rollback networking.

Could you expand on the ROM game commands bit? Does it mean that all actions are serialized?

tantalor 6y ago

It's a networked game... how else could it work?

jldugger 6y ago
I just don't know what a 'ROM game command' is. Seems more likely it would be controller inputs to one person's emulator? Or perhaps everyone has an emulator and the inputs are simply shared.
- read_if_gay_ 6y ago
  To me it seems like just a somewhat awkward way to phrase exactly what you think it means.
- JoeOfTexas 6y ago
  These things usually work by syncing the emulator clocks between clients, and then sending player inputs over the network along with the data to sync.
- sktrdie 6y ago
  It’s probably really simple: if you normally load a ROM game and start a multiplayer game you control all the other players input. This simply goes next step and makes other inputs be controlled by other players.
  - mrmonkeyman 6y ago
    That has nothing to do with "ROM".

Vel0cityX 6y ago

> ROM game commands This phrase doesn't mean anything. The game list includes games that do not support PlayStation Link Cable, so this has to implement netplay the same way other emulators do: Both host and client emulate the game in sync, exchanging controller input Edit: Seems like I was wrong about the latter, it runs the emulator on the host only, who sends video/audio from clients (and they send inputs).

danbolt 6y ago
I’d be curious to see how feasible a rollback-based implementation would be for emulating the game.
- ohyeshedid 6y ago
  If you're referring to constantly sending save states back and forth, some emulators work this way currently. If I'm not mistaken, RetroArch's networking functions in that way.
  - reitzensteinm 6y ago
    Rollback networking is essentially event sourcing. Game states are immutable, and new game states are derived from adding inputs (events). You keep the last dozen game states around in memory, and if you receive an input from the past, you rewind to the last game state prior, add it to your input stream, and fast forward to the present. It has the same base advantages and drawbacks as RTS networking - the core logic is written as though the game is single player, and complexity can be scaled arbitrarily without bloating bandwidth requirements. But in addition, you get the benefit of zero input latency (play a multiplayer RTS game and send a unit around - they won't move for 200ms or so), and the drawback of an absolute clusterfuck time rewind debugging madness if any inadvertent mutation of your immutable data happens. The reason you do rollback with something like this is it gives you zero latency, and you can retrofit it on to an emulator without changing any game code just by using memcpy() on the game state. Source: I've developed about a dozen titles using rollback networking.