Synced co-op pause for Black Ops II Zombies (Plutonium T6)

by Xep

Any player can pause. Any player can unpause. The state lives on level, so it's
identical for everyone — there's no per-client state that can desync.

• Zombies stop where they are, and stop spawning
• Players are locked and can't be hurt
• The match clock, powerup timers, effect countdowns and bleedout all hold
• Resumes on a 3‑2‑1 countdown with a short grace period

Requirements

Plutonium T6 (Black Ops II), zombies. No other mods or dependencies.

Download & Source

Latest Version Download:

github dot com/Xeptix/ZPause/releases/tag/public/latest

GitHub Source Code:

github dot com/Xeptix/ZPause

Install

Two packagings of the same file are included. Plutonium only lets you enable one mod
at a time, so the script version is usually the better choice — it coexists with whatever
mod you're running.

Script version (recommended)

Drop zpause.gsc into your T6 storage scripts folder:

%localappdata%\Plutonium\storage\t6\scripts\zm\zpause.gsc

On newer Plutonium builds the path is under raw:

%localappdata%\Plutonium\storage\t6\raw\scripts\zm\zpause.gsc

If you aren't sure which your build uses, put it in both — only the one that exists will
be read.

Mod version

Copy the zm_pause folder into your mods folder:

%localappdata%\Plutonium\storage\t6\mods\zm_pause\scripts\zm\zpause.gsc

Then pick zm_pause from the in-game Mods menu. The folder name must keep its zm_
prefix or it won't show up in the zombies mod list.

You don't need to restart the game to reload a script — just end the current game and
start a new one.

Usage

The button combo keeps working while you're frozen — freezecontrols() blocks movement
and weapon use, but button state still reaches the server. That's what lets a frozen
player resume without opening chat.

Resuming runs a 3‑2‑1 countdown with everything still frozen, then releases the whole
game at once and gives players 2 seconds of invulnerability so nobody eats a hit from a
zombie that was mid‑swing.

Configuration

Every setting is at the top of the file under zp_load_config(), and each one is also a
dvar of the same name. The script creates each dvar with its default on load, so you can
set them straight from the console:

zp_countdown 5

The config is re-read at the start of every pause, so a change takes effect on the next
pause — no map restart needed. Anything already set in your config.cfg before the map
loads is left alone.

How it works

Treyarch already shipped a working full-game pause in T6 zombies. It's what runs
during a host migration. The stock script maps\mp\gametypes_zm\_hostmigration.gsc does
exactly this:

disablezombies( 1 );            // engine-level AI freeze
flag_clear( "spawn_zombies" );  // the spawner's own gate
player freezecontrols( 1 );     // lock players
player enableinvulnerability(); // nobody can be hurt
locktimer();                    // hold level.discardtime so the clock stops

…and the exact inverse to resume. ZPause uses that recipe rather than inventing one, so
the spawner, the round counter and the match clock are all stopped the way the game
expects:

• disablezombies() / enablezombies() are engine builtins — the same calls host
  migration uses.
• flag_clear("spawn_zombies") is the flag _zm.gsc's spawn loop actually blocks on,
  so spawning stops at the source instead of being fought.
• level.discardtime is subtracted from the match clock, so pushing it forward by the
  elapsed time holds the timer still.

On top of that, ZPause covers what host migration never has to because it only lasts a few
seconds:

• An AI enforcer that re-freezes anything appearing mid-pause, keeps ignoreall
  pinned, and snaps back any AI that drifts. It's a safety net — if the engine freeze does
  its job it never fires, so there's no jitter.
• The stuck-zombie watchdog. round_spawn_failsafe() kills any zombie that hasn't
  moved 24 units in 30 seconds (15 on Origins and Mob of the Dead), assuming it's stuck
  outside the playspace. A paused zombie trips it every time, and the "put it back in the
  spawn queue" compensation is skipped for anything with ignoreall set — so those
  zombies are gone for good, counted as killed, and the round advances while everyone's
  away. ZPause keeps the barrier-chunk timestamp fresh, which all three variants honour,
  so the watchdog loops harmlessly instead of firing and still works normally afterwards.
• Ground powerups. powerup_timeout() is a plain wait() and can't be paused, so the
  thread is cut and restarted on resume.
• Insta-kill / double points. Their HUD countdowns are held still. The 30s wait()
  driving the real effect keeps running underneath, so on resume a bounded thread holds
  the effect on until the frozen countdown genuinely runs out, then forces it off —
  without that, the effect would stick on for the rest of the game.
• Bleedout is pinned so a downed player doesn't bleed out.
• Late joiners and respawns are frozen on spawn, and everything is torn down on
  end_game so nobody is left frozen at the scoreboard.

Why not timescale?

timescale 0 looks like the perfect pause — it would freeze everything, timers included.
But GSC wait runs on server time, so the unpause loop freezes with it and the game can
never be resumed. The server also only runs a frame once enough scaled time accumulates,
so snapshots stop going out and clients drop with Connection Interrupted. Slow motion
(timescale 0.05) avoids the disconnects but isn't a pause.

Notes

• Round transitions. Pausing between rounds doesn't stop the next round from
  beginning — its delay is a plain wait(). No zombies spawn until you resume.
• Ground powerups get a fresh timer on resume rather than their exact remaining time,
  so you'll never lose a Max Ammo to a pause.
• Zombies stand idle rather than freeze solid. zp_freeze_anims puts them in the
  game's dormant-zombie pose so they don't run on the spot, but it's an idle animation
  rather than a hard freeze. A true animation freeze isn't reachable from server-side GSC,
  and the same applies to player animations.
• Scripted boss sequences (Brutus spawn-ins, Panzers, ghosts, the Avogadro) are held
  in place, but a scripted move already underway can still finish.
• Not held: magic box close timer, teleporter cooldowns, trap durations, and Easter
  egg step timers.

Testing

Tested in live co-op games, including on custom map ports.

It's also compile-checked with gsc-tool 1.4.10 targeting t6/pc against the stock
script tree, and round-tripped through compile → decompile. Every external function it
calls exists in the stock T6 script corpus.

Credits

• Xep — author
• Treyarch — _hostmigration.gsc, the pause recipe this is built on
• plutoniummod/t6-scripts — stock T6 script reference
• hima_simple — earliest BO2 zombies pause script
• DED2SIN — Plutonium pause script building on it
• MufaDOOM — BO2 co-op pause mod
• Resxt — Plutonium T6 chat command conventions