Gen2Online

Online multiplayer layer for UNDERdecoded/Gen2Recomped — a port of Gen1Online adapted for Pokémon Gold / Silver (Gen 2).

Version: 0.7.0-gen2

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What this is

Gen1Online added GTS, overworld multiplayer, link trade/battle, quests, and accounts to Gen1 recompilations.
Gen2Online keeps that design and rewires it for Gen2Recomp:

Area	Gen1Online	Gen2Online
Games	Red / Blue / Yellow	Gold / Silver (+ Gen1 still possible via same server)
Start map	Pallet / Red’s house	New Bark — PLAYERS_HOUSE2_F
Avatars	Red / Blue sprites	Chris / Kris (+ trainer fallbacks)
Species	151	251 via engine data
Party wire format	Gen1 fields	Gen1 + heldItem, happiness, pokerus, met data, shiny
PVP / GTS	Open	Same-generation only (Gen1 ↔ Gen2 blocked)
Quests	Kanto-focused	Johto → Gen2 Kanto → League → Mt. Silver (27 quests)
DayCare	—	Online XP on withdraw
National Park	—	Online contest host (quest 1027)
Game Corner	Celadon	Goldenrod map hooks

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Requirements

• Gen2Recomp with Gold or Silver ROM extracted
• Python 3 (for gts_server.py)
• Network permission in the mod manifest

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Install

1. Copy this folder to:

   Gen2Recomped/mods/gen2online/
   

2. Enable the mod (needs engine_internals + network).

3. Point the client at your server in main.lua:

   local GTS_SERVER_URL = "https://gts.yourdomain.com"
   -- or http://127.0.0.1:7779 for local only

4. Run the server (must match mod version 0.7.0-gen2):

   python3 gts_server.py
   # PORT=7779 by default; binds 0.0.0.0

5. In-game: START → CONNECT TO SERVER.

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Hosting (multiplayer)

Recommended:

• Small VPS (e.g. Contabo / Hetzner / DigitalOcean)
• gts_server.py under systemd
• Cloudflare Tunnel to a stable HTTPS hostname (no public 7779 required)

Example client URL:

local GTS_SERVER_URL = "https://gts.cedricslabs.com"

Persist:

• gts_database.json
• players_backup.json

Quick tunnel URLs (*.trycloudflare.com) change every restart; named tunnels + your domain do not.

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Changes from original Gen1Online

Boot & saves

• Detects Gen2 via GameVersion.isGen2() / gold / silver.
• New Game / online create / redeem / connect force Gen2 start away from Pallet:
  • Indoor: PLAYERS_HOUSE2_F (player’s bedroom)
  • Outdoor landmark: NEW_BARK_TOWN
• Hooks SaveData.newGame and OverworldState.enter so Phase 2B no longer leaves Gold/Silver in REDS_HOUSE_2F.
• Online saves remain separate (save_online_*.lua style suffixes for gold/silver).
• RESET / SWITCH clears online files safely and opens fresh character creation (no longer hardcodes Red’s house).

Sprites

• Safe sprite loading: never call SpriteRenderer.new on missing PNGs.
• Avatar fallback excludes SPRITE_MON_* / SPRITE_WILD_* (fixed “player looks like a Pokémon”).
• Remote players and quest NPCs use pcall + human trainer sprite fallbacks.
• Redeem Token uses NamingScreen + game.stack:push (no global Screens dependency).

GTS & wire format (gen2_compat.lua)

• packMon / unpackMon / packParty carry Gen2 fields.
• GTS deposits tag generation.
• Browse / trade reject cross-gen listings.
• PVP rejects Gen1 ↔ Gen2 parties.

Link trade & battle

• Same Gen1Online room/challenge model.
• Bug fixed: some sync_pos posts omitted modVersion, so the server returned VERSION_MISMATCH even when both sides showed 0.7.0-gen2.
  • Background HTTP thread injects modVersion if missing.
  • All sync_pos payloads include version.
  • Server accepts X-Mod-Version header as fallback and is lenient on 0.7.x-gen2.

Quests (IDs 1001–1027)

Online side storyline (does not replace ROM gym/E4 AI):

Johto (1001–1016)
Welcome, Sprout Tower, Cherrygrove, Route 29, Slowpoke Well, Underground, Burned Tower, Lake of Rage, Olivine, Cianwood, Radio Tower, Ice Path, Dragon’s Den, Tohjo, Viridian customs, Indigo report.

Gen2 Kanto (1017–1024)
Pewter → Cerulean → Vermilion → Celadon → Fuchsia (Janine) → Saffron → Cinnabar → Viridian (Blue).

League (1025)
Victory Road + Will / Koga / Bruno / Karen / Lance seals (fallback spawns in Indigo PC if room maps are stubs).

Mt. Silver (1026)
Silver Cave emblem + Summit Trainer finale.

National Park (1027)
Online contest host checkpoint.

Guide Mira in New Bark tracks the board.

Other Gen2 hooks

• Goldenrod Game Corner registration.
• DayCare withdraw → small online XP.
• Time-of-day line on connect.
• Gen2 trade NPC hooks where applicable.

Server (gts_server.py)

• MOD_VERSION = "0.7.0-gen2".
• Quest defs through 1027.
• Generation-aware deposits / profiles.
• Same multi-threaded GTS + overworld + challenge rooms model as Gen1Online.

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What is not replaced

Still provided by Gen2Recomp + ROM extract:

• Real gym / Elite Four / Red battles and AI
• Full map geometry (stub maps stay limited until extract is complete)
• Day/night engine, Pokégear, breeding rules, Bug Contest scoring

This mod is the online layer on top.

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Troubleshooting

Symptom	Fix
VERSION MISMATCH with same 0.7.0-gen2	Update both client main.lua and VPS gts_server.py to 0.7 package; restart gen2online-gts
Spawn in Pallet online	Use latest mod; RESET / SWITCH online character once
Redeem Token crash (Screens nil)	Use latest main.lua (NamingScreen path)
Player sprite is a Pokémon	Use latest sprite fallback logic
Can’t connect	Check GTS_SERVER_URL, server process, Cloudflare tunnel / DNS
Empty Oak’s desk	You’re on Gen1 maps; Gold/Silver should start in New Bark / Elm path

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File layout

gen2online/
  main.lua              # Mod entry, net, GTS UI, hooks
  gen2_compat.lua       # Gen2 detection, spawn, packMon, filters
  gts_server.py         # Shared multiplayer server
  manifest.json
  INSTALL.md
  quests/               # 1001–1027 definitions
  npcs/                 # Mira, Johto/Kanto/League/Silver hosts
  transforms.lua
  ...

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Credits

• Original online design: Gen1Online
• Engine: Gen2Recomp (UNDERdecoded)
• Gen2 adaptations, Johto–Kanto online questline, spawn/sprite/version fixes: this package

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License / ROM data

Ship only scaffolds and your own code. Do not commit extracted Nintendo map/graphics data. Players supply their own ROMs through Gen2Recomp’s legal extract pipeline.