ModNet_CoopChat.lua

The same co-op text chat as coopchat.lua, rebuilt on top of ModNet instead of a hand-rolled transport — worth reading side by side with the original to see exactly what moving to the library actually removes.

Use this OR coopchat.lua, never both at once — both hijack the identical event id (MrxFactionManager, EV_CHAT/M.EV = 5), so running both simultaneously means each would misinterpret the other’s traffic as its own.

What changed, concretely

Every piece of the original that was really “the network problem” — the hijack install, the pack/unpack-bytes encoding, chunking, reassembly, the sender-id scheme — is simply gone from this file. What’s left is close to pure UI glue:

ModNet.Send(CH, text)                                    -- was: SendChat(text), ~15 lines of packing
ModNet.On(CH, function(sender, text) ... end)             -- was: a hand-rolled NetEventCallback hijack

ModNet.Send/On already handle arbitrary Lua values (strings included), so there’s no equivalent of packBytes/unpackBytes or the reassembly buffer here at all — that’s all inside ModNet now, shared with anything else built on it. What stays, because it’s genuinely specific to this feature, not the network layer: the UI.Chat window itself, the movement-freeze wrap around prompt()/_endInput(), and retitling the local echo to "P<id>: text".

Setup

Both machines, in order: uilib.lua (OnLoad), then ModNet.lua (OnLoad) — both before this file.
Copy this file to scripts/OnKey/ModNet_CoopChat.lua, add ModNet_CoopChat.lua=f2 under [OnKey].
Press F2 to open the input line. Type, Enter sends, Esc cancels.

The full script

local KEYVAL = "f2"   -- must be in the first 10 lines (add "ModNet_CoopChat.lua=f2" under [OnKey])

-- ModNet_CoopChat.lua -- co-op text chat, refit onto the ModNet transport.
--
-- All the hard parts (hijack, pack/chunk, reassembly, sender id) now live in
-- ModNet. This file is just UI glue: send typed lines on the "chat" channel,
-- show received lines titled P1/P2, and freeze movement while typing. Compare
-- to coopchat.lua to see how much the library absorbs.
--
-- DEPLOY (both machines): OnLoad\uilib.lua AND OnLoad\ModNet.lua load first.
-- Then OnKey\ModNet_CoopChat.lua with  ModNet_CoopChat.lua=f2  under [OnKey].
-- NOTE: use this OR coopchat.lua, not both -- they'd both claim the wire.
----------------------------------------------------------------------------

if not (_G.UI and UI.Chat) then
  if Loader and Loader.Printf then Loader.Printf("[coopchat] load uilib.lua first") end
  return
end
if not _G.ModNet then
  if Loader and Loader.Printf then Loader.Printf("[coopchat] load ModNet.lua first") end
  return
end

local CH = "chat"

local function try(f, ...) if type(f) == "function" then local ok, v = pcall(f, ...); if ok then return v end end end
local function myId()
  return try(Player and Player.GetLocalPlayerId) or try(Player and Player.GetLocalId)
      or ((Net and Net.IsServer and Net.IsServer()) and 0 or 1)
end
local function label(id) return "P" .. (tonumber(id or 0) + 1) end   -- 0/1 -> P1/P2

-- freeze/unfreeze local player movement (game control gate; leaves chat input intact)
local function setMove(on)
  local p = try(Player and Player.GetLocalPlayer)
  if p and Player.SetInputEnabled then pcall(Player.SetInputEnabled, p, on) end
end

-- onSubmit: send over ModNet, then retitle prompt's bare local echo to "P<me>: text"
local function onSubmit(text)
  ModNet.Send(CH, text)
  local ui = _G.COOPCHAT2 and _G.COOPCHAT2.ui
  if ui then
    local wrap = UI.wrap and UI.wrap(text, 52)
    if type(wrap) == "table" and ui._log then
      for _ = 1, #wrap do table.remove(ui._log) end   -- drop the bare lines prompt just pushed
      ui:push(label(myId()) .. ": " .. text)           -- re-push titled
    end
  end
end

-- ===== build once: the UI.Chat window + movement wraps =====
if not _G.COOPCHAT2 then
  _G.COOPCHAT2 = {}
  local C = _G.COOPCHAT2
  C.ui = UI.Chat{ x = 20, y = 330, w = 384, title = "CO-OP CHAT", onSubmit = onSubmit }

  local basePrompt, baseEnd = C.ui.prompt, C.ui._endInput
  C.ui.prompt    = function(self, cb) setMove(false); return basePrompt(self, cb) end
  C.ui._endInput = function(self)     setMove(true);  return baseEnd(self)      end

  C.ui:push("[co-op chat ready -- press " .. KEYVAL .. " to type]")
  Loader.Printf("[coopchat] built on ModNet")
end

-- ===== each keypress: (re)register receiver (idempotent), then open the input line =====
ModNet.On(CH, function(sender, text)
  local ui = _G.COOPCHAT2 and _G.COOPCHAT2.ui
  if ui and type(text) == "string" then ui:push(label(sender) .. ": " .. text) end
end)

_G.COOPCHAT2.ui:prompt(onSubmit)

ModNet_CoopChat.lua

What changed, concretely

Setup

The full script

See also