Documentation

Run a server for a single game. This will block until the game ends, specifically when all players have disconnected.

Start a client. This blocks until the initial handshake with the server is finished. You must call clientSetInput on the returned client to submit new inputs.

Think of world as shared state between all clients. Alpaca NetCode takes care of synchronizing and predicting the world state across all clients. Additionally, clock synchronization is done with the server and the "current" tick is decided for you when sampling with clientSample.

Typical usage looks like this:

   main :: IO ()
   main = do
     myClient <- runClient "localhost" "8111" 30 myInput0 myWorld0 worldStep
     let myPlayerId = clientPlayerId myClient

     mainGameLoop $ do
       myInput <- pollInput          -- Poll inputs from some other library
       clientSetInput myClient       -- Push inputs to Alpaca NetCode
       world <- clientSample         -- Sample the current (predicted) world
       renderWorld myPlayerId world  -- Render the world

       -- You're free to do IO and maintain state local to the client.

       return (gameIsOver world)     -- Return True to keep looping

   clientStop myClient

   -- Given
   data World = World { .. }
   data Input = Input { .. } deriving (Generic, Eq, Flat)
   myWorld0 :: World
   gameIsOver :: World -> Bool
   myInput0 :: Input
   worldStep :: Map PlayerId Input -> Tick -> World -> World
   renderWorld :: PlayerId -> World -> IO ()
   pollInput :: IO Input
   mainGameLoop :: IO Bool -> IO ()

A Client. You'll generally obtain this via runClient.

The client's PlayerId

Sample the current world state.

. First, This will estimate the current tick based on ping and clock synchronization with the server. Then, this extrapolates past the latest know authoritative world state by assuming no user inputs have changed (unless otherwise known e.g. our own player's inputs are known). If the client has been stopped, this will return the last predicted world.

Set the client's current input.

Stop the client.

The game is broken into discrete ticks starting from 0.

Either a host name e.g., "haskell.org" or a numeric host address string consisting of a dotted decimal IPv4 address or an IPv6 address e.g., "192.168.0.1".

Either a service name e.g., "http" or a numeric port number.