📜 WAC scripting basics

WAC is the script language that makes things happen in a Joint Ops map: timed events, weather, messages, AI orders, sounds, effects, win and lose. How a script is laid out, when it runs, what multiplayer players actually see, and the traps that fail without a word.

Tested in a real match (13 Oct 2026)

Every one of the 165 commands was fired on a LAN host (normal retail behaviour, stock map 03TR) with a second player joined, and we recorded what the host and the joining player each saw: object states from both games, plus screenshots from both screens. Results:

The result for each command is on its card. The things most likely to catch a mapper out:

• Inside PLOOP, player is the player's slot number, not 10000/10001. On the test map the host was 88 and the joiner 89. A script that compares player with 10000 never fires. Use pisteam, or flags set with psetvar and read with pisvar.
• SSNdead goes false again about 30 seconds after the kill, when the body is cleared away (SSNexists too). Killed wildlife even comes back. Catch a death the moment it happens: if ssndead(1704) and never then set(V1, 1) endif.
• reset(name) only works if the reset line comes after its named IF in the script. Written before the IF, it does nothing, with no error.
• SSNHP, SSNADDHP and GroupHP change a soldier's or animal's health on the server only. Players' screens keep the old number, but the server decides damage and death, so the game still plays right. Vehicle health does reach players.
• sound(...) threw the joining player out of the game with one sound name (SS_PSP_LOST); SS_EXPLO_BASE was fine. Do not use sound in multiplayer.
• fall throws the host's player about 470 m into the air, which kills with normal health, and tele keeps the fall speed.
• fov does nothing (tried 20, 40 and 120).
• win and lose end the round for everyone; on the test map it showed "Draw - No winner!".
• Weather that reaches players: rain, snow, overcast, skyspeed, TOD, fogdist, movefog, quake. Server's screen only: gain, skyheight, floor, ceiling.

Still to prove (the 41): mostly AI aim and distance settings, flashes and lightning (too short to catch in a screenshot so far), sounds (a screenshot cannot hear), fire-button tests, and commands this map has nothing for (doors, location boxes, spawn points). They will be retested and the cards updated.

Files

• Name: the map's script has the same name as its .bms, with .wac on the end: TD-ShippingPort.BMS uses TD-ShippingPort.WAC. Put it with the .bms. Capitals do not matter.
• Two more files run with every map: game.wac and server.wac. At map load the game reads game.wac, then server.wac, then the map's own .wac, and joins them into one script. Any of them can be missing: the game skips it without a message.
• Line endings must be Windows style (CRLF). The game only counts a carriage return as the end of a line. In a file with Unix (LF-only) endings the first // comment runs to the end of the file, so the rest of the script quietly does nothing, with no error.
• RUN pulls another file in at that point: RUN extra.wac. Use it at the top level only (not inside an IF or a loop). A RUN file can RUN one more file; a third level is refused.

Who runs it, and when

• Only the host runs the script. On a dedicated server that is the server; on a listen server the hosting player's PC; in single player your PC. Players who join do not run anything: they only see what the host's script does to the game (see multiplayer).
• At map load the script is compiled and run once straight away (pass 0). After that it runs once every 62 game ticks, about once a second.
• Every "seconds" value is really a count of script passes. past(60) means "the 60th pass or later". The pass counter is the value ticks.
• An empty server sleeps. While no human player is in, the world and the script stop, and past, elapse and ontick pause with them.
• A compile mistake never stops a map. The script runs anyway, with the broken part treated as 0 (see compiler messages).

How a script is written

• Comments: // or ; to the end of the line.
• Capitals do not matter for commands, keywords and names.
• Spaces, tabs and commas all separate words, and brackets are optional. These are the same:

  fogdist(200)
  fogdist 200
  ceiling 40 20 20
  ceiling(40, 20, 20)

• Text goes in double quotes: text("Hello"). Up to 63 characters are kept.
• Keywords match on their first four letters. ENDIF, ENDLOOP, ENDDO and END are all END.
• Each command takes a fixed number of values. There are no optional values. Give too few and the command takes the next words of the script as its values, even from the following lines, and can swallow your ENDIF. Extra values are quietly ignored: wave(x.wav, 600) plays the wave and ignores the 600.

IF blocks

These forms come from the game's own built-in help:

IF triggers THEN actions END
IF [name] triggers THEN actions END        (a named IF, for reset)
IF triggers THEN actions ELSE actions END
IF triggers THEN actions ELSEIF triggers THEN actions END
IF triggers ENTER actions END              (runs once when the triggers become true)
IF triggers LEAVE actions END              (runs once when they stop being true)
PLOOP actions END                          (once for each human player)
GLOOP group actions END                    (once for each member of a group)
DOSEQ actions NEXT actions [NEXT actions ...] END
DORND actions NEXT actions [NEXT actions ...] END

• The script runs top to bottom on every pass, and each IF tests its triggers every pass.
• THEN runs on every pass while the triggers are true. if past(10) then flash endif flashes every second from then on. To run something once, add never. To repeat it every N seconds, add elapse(N).
• ENTER runs only on the pass where the triggers turn true; LEAVE only on the pass where they stop being true.
• ELSE runs when the IF did not fire.
• ELSEIF must be one word. ELSE IF (two words) opens a second, nested IF that needs its own END, or the script ends with "Missing END". Several retail training scripts ship with this mistake.
• IFs can be nested inside THEN and ELSE parts.
• Named IFs: IF [gate] ... gives the IF a name. reset(gate) clears that IF's "has fired" memory (and that of the IFs inside it), so never, elapse and chain work again. The reset line must come after the named IF in the script (proven in the live test: before it, reset does nothing).

Combining triggers

• AND, OR and NOT (also &&, ||, !): if ssndead(404) and ssndead(405) and never then.
• AND and OR have the same priority and are read left to right. a OR b AND c means (a OR b) AND c. Use brackets whenever you mix them.
• Comparisons work in an IF: if V1 < 12 then, if V1 == 3 and V2 != 0 then (< > <= >= == != <>). The commands eq, ne, lt, gt, le, ge do the same job.

Timing words

All count script passes, about one second each.

DOSEQ and DORND

Each time the block is reached it runs one section and moves to the next section next time. DORND is not random in Joint Ops: it cycles through its sections in order, exactly like DOSEQ. For randomness use random(N) in an IF.

Loops: PLOOP and GLOOP

• PLOOP ... END repeats its contents once for each human player. Inside it, player is the current player's SSN, and the per-player commands (ptext, pwave, pconsol, onptick, piskills, pisvar, psetvar, pisteam, ppunt, pkillpunt) work on that player.
• GLOOP G_name ... END does the same for every member of a script group. Built-in groups: G_humans, G_blueplayers, G_redplayers, G_ai, G_blueai, G_redai, G_emptygroup. Always write the G_. A bare humans is the player count, not the group.
• Script groups are not the group numbers you set in MED. Commands that take a number (kill(6), GtoWP(4, 2), groupdead(3)) use MED group numbers; commands that take a group (Gkill, Gremove, GLOOP) use script groups.
• A loop cannot sit inside another loop ("No LOOP Nesting!").

Values and variables

Named values

Setting values: use set(V1, 5), add(V1, 2), sub, inc(V1), dec(V1). The game also accepts V1 = 5, but arithmetic in assignments is unreliable: V1 = 1 + 2 * 3 stores 1, not 7. Keep to one operation per line, or use the commands.

Limits

Compiler messages

The game keeps only the first message, shown as file (line) message on the game's script debug display. Whatever the message, the script still runs: the broken value becomes 0, so a typo usually means "that line quietly does nothing", or worse, "acts on object 0 or IF 0".

Traps with no message at all: LF line endings; a misspelled name in reset; a text key that does not exist; a missing G_ before a group name; extra values after a command.

Multiplayer: what other players see

The script runs only on the host, so what matters is how each command's effect reaches the other players. The game marks every command:

• Host actions on objects (kill, remove, health, AI orders, doors, teleport, spawn counts) change the game on the host, and players see the result through the normal game updates.
• Sent commands (text, consol, wave, SSNwave, hideSSN, quake, flash, effects ...) are passed on and run on every player's PC. ptext, pwave and pconsol go to one player (the one PLOOP picked).
• Weather: rain, snow, overcast, fogdist, movefog, TOD and skyspeed run on the host, and the game's regular weather update carries them to players. skyheight, fogtype and gain do not reach other players.
• "Your own player" commands (area, area3D, location, outside, me..., weaponfired, blockfire, anim, fov, tele, fall, ammorain, fxrain) mean the host's own player. They suit single player; a dedicated server has no such player. For every player in multiplayer use PLOOP with SSNarea(player, N) or SSNonSSN(player, N).
• Colours need the FMJ onHook DLL: see WAC colour commands.
• Sound sets (sound, sound2tgt, SS2SSN) are sent in a way that may not match on every PC. Whether players hear the right sound is not verified, and a bad value may crash a client. Test before relying on them in multiplayer.

Commands that do nothing, or not what they say

• teleSSN does not move the object (a retail bug, confirmed in the live test). Use teleport(group, target), which moved its soldier exactly onto the target on both screens.
• fov changes nothing (live test: 20, 40 and 120).
• sound threw a joining player out of the game in the live test (with SS_PSP_LOST). Do not use it in multiplayer.
• music, sunfade, squadevent (always false), pisgold (always false), squadclear, ssnface and face (Joint Ops has no face files) have no visible effect.
• DORND is not random.
• random(N): from the code it is true about 1 time in 2N (random(4) about 1 in 8), not 1 in N as Nile's text says. Not measured in game.
• lose(team) accepts only 0 or 1, and by the code always ends with Red winning. In the live test on 03TR, win and lose both ended the round for everyone with "Draw - No winner!".
• crash is an old copy of skyfogcolor: use skyfogcolor.
• quake(N) lasts about N tenths of a second, not N seconds.
• fall, ammorain and fxrain may crash a dedicated server, because there is no host player (not tested on a dedicated server). On a listen host, fall threw the host's player about 470 m up.

Names in Nile's action list that are not real commands

• wind(kph, seconds): added by the FMJ onHook DLL only. On a normal install it compiles to nothing and gives no error.
• ssnblind, ssnclimb: not in the game's table, so they give "Unknown".
• fov(SSN, N): the real fov takes one number and sets the host's own camera.
• SSNLeadSSN2SSN is offered with 3 values; the game needs 4.

Example scripts

The SSNs, areas and file names belong to their maps: use your own.

A. Map start, a repair pad and a crane disaster

From TAC's AS-KutuTowerAssault.WAC, shortened.

//map start: runs once on the first pass
if never then
hidessn(3188)          //fallen beam, shown later
killssn(4125)
movefog(200, 0)
fogtype(3)
tod(9:00)              //the original wrote set(tod, 09:00), which does nothing
overcast(45, 0)
ssn2ssn(4138, 4139)    //put a soldier on a gun
ssnuse(4138)
endif

//heli pad repair: every 30 s while the helo sits on the pad
if SSNonSSN(4137, 4136) and elapse(30) then
SSNHP(4137, 8000)
endif

//crane beam drop: a timed sequence, each step after the one above
if ssnride(3405) and never then
ssnwave(2265, "m1rtrev2.wav", 250)
endif
if chain(5) and never then
killssn(3404)
ssnwave(3403, "alarm9.wav", 50)
endif
if chain(5) and never then
ammo2tgt(ARTYRND, 2)
hidessn(2648)
unhidessn(3188)
endif
if chain(4) and never then
removessn(3405)
endif

B. A storm rising after 15 minutes

From TAC's AS-VillaValleyTAC.WAC, shortened (its wind(...) lines are left out: they need the FMJ DLL).

if never() and (OnTick(0)) then    //set the start weather
tod(8)
fogdist(1024)
endif

if Elapse(900) and Past(5) then
farflash()
movefog(20, 50)
overcast(100, 40)
rain(100, 40)
consol("TYPHOON RISING - TAKE CARE!")
endif

if chain(10) then
farflash()
endif
if chain(5) then
flash()
quake(10)
movefog(60, 5)
endif

if chain(5) then                   //clear again
overcast(0, 10)
rain(0, 10)
movefog(1024, 60)
consol("Fog Clear")
endif

C. Seats for every player, and a welcome

The seat part is from TAC's TK-AlQurnahBasin.WAC (made in Nile, fixed by O.M.).

// a player who steps on the pad (133031) is put in the chair (133035)
PLOOP
    if ssnonssn(player, 133031) then
        ssn2ssn(player, 133035)
        ssnuse(player)
    endif
END

// let people out of the chair again
if ssnride(133035) then
    PLOOP
        if ssnonssn(player, 133035) then
            ssnrelease(player)
        endif
    END
endif

// only the player who has just joined sees this
PLOOP
if onptick(20) then
ptext("Welcome to the server!")
endif
END