A bit of cross posting here. Theres a dev blog here about doing the above.
https://forum.defold.com/t/building-a-multiplayer-server/
The server and client system I built has a state buffer system (very rudimentary). I was hoping to use Nakama but there were issues (as noted above).
The state buffer system in SWAMPY is simple - it has been implemented in the warbattlesmp module using websockets.
Operation is:
- Clients connect using http and if there is no game, one is created.
- Other clients join (using http) and then are given a websocket port to communicate on once joined.
- During init of a client, it is sent the tanks starting positions, other players and initial start info.
- Client has a tank “pathing system” that uses start positions and game.frame time to set position of tanks during the game. No state buffer here - all algorithm based tank positions (much simpler).
- Client starts sending changes in player movement and any shoot events
- Server puts events into a list which is regularly parsed and sent to all players - this is the state buffer.
- Clients receive the state buffer from the server and apply to “other” players in their game.
- Rockets are also sent in state buffers (from the shoot event) and are replicated in the clients.
Again, this is a very simple implementation of such a system. Normally the state buffer would be frame or time “keyed”. This allows the server to sync checks to validate things like:
- who killed a tank first (who gets the points)
- whether the players positions are valid for the time/frame on the server
- check if any incoming data is not spoofed or fake. Usually time/frame + checksum or code.
While not currently implemented, this is relatively easy to add, and I will hopefully put something like this on before xmas.
Otherwise it should give people an idea of how this sort of system works.