Camouflage & stealth¶

Vanilla JA2 had one camouflage kit and a sneak button. 1.13 turns "not being seen" into a system of its own: four camouflage types matched against the terrain you are standing on, camouflaged clothing and load-bearing gear, stealth-rated equipment, per-tile noise rolls, and a fully configurable enemy-vision model. This page explains how enemies detect you and every lever you have to avoid it. All numbers below are defaults from the current GitHub-era Data-1.13\Ja2_Options.INI and Data-1.13\Skills_Settings.INI, cross-checked against the current source code.

How enemies spot you¶

Whether an enemy sees your merc is a sight-range test: the spotter has a base view distance, and everything about your merc and their surroundings stretches or shrinks it. The current code combines these factors:

Light. Sight range scales with the light level at the target's position. BASE_SIGHT_RANGE = 14 in [Tactical Vision Settings] (vanilla used 13), and the BRIGHTNESS_MOD_0 … BRIGHTNESS_MOD_15 keys map light levels to a percentage of that range: normal daylight (level 3) is 100%, normal night (level 12) is 43%, and the darkest level is 9%.
Stance. Being low makes you harder to see: prone gives a 10% sight-range reduction at default settings, crouching 6% (COVER_SYSTEM_STANCE_EFFECTIVENESS). Stance also multiplies your camouflage — see below.
Movement. Every tile you moved this turn adds visibility. The penalty is scaled by brightness (moving in daylight is far worse than at night), reduced by your stealth gear, and reduced another 25% for Stealthy mercs.
Bulk. Big gear silhouettes you: the LBE check adds visibility for large items in your hands, a slung weapon, a combat pack and — worst of all — a backpack (COVER_SYSTEM_LBE_EFFECTIVENESS). Dropping backpacks before a fight (Shift+B) is not just about weight.
Camouflage matching the terrain you stand on, and stealth-rated equipment (both explained below).
Intervening objects. Trees, rocks and similar dense objects between you and the spotter degrade their vision (COVER_SYSTEM_TREE_EFFECTIVENESS); walls block it completely.
Facing. With ALLOW_TUNNEL_VISION = TRUE (the default) nobody sees behind themselves, and some scopes and headgear narrow the field of view further.

You don't have to compute any of this yourself — the game shows you. Press F over a tile for a full report (cover, brightness, camouflage, stealth, terrain properties), hold Del to color every tile by how well hidden you would be there from the enemies' point of view, and hold End to see what your own merc can see. The full set of overlay keys is on the hotkeys page.

The spotter matters too: enemy quality and equipment (night-vision gear on elites, for example) rise with campaign progress — see Know your enemy. Staying unseen also feeds other systems: the improved interrupt system is built on awareness, so an enemy who hasn't seen or heard you is at a severe disadvantage — and unheard, unseen kills keep the rest of the map calm.

The whole model is tunable in [Tactical Cover System Settings] of Ja2_Options.INI:

Setting	Default	What it scales
`COVER_SYSTEM_CAMOUFLAGE_EFFECTIVENESS`	`80`	Maximum sight reduction from 100% terrain-matched camo. `0` disables camouflage entirely.
`COVER_SYSTEM_STEALTH_EFFECTIVENESS`	`50`	Maximum sight reduction from 100 stealth (in darkness).
`COVER_SYSTEM_STANCE_EFFECTIVENESS`	`10`	Sight reduction for being prone.
`COVER_SYSTEM_MOVEMENT_EFFECTIVENESS`	`20`	Visibility penalty for tiles moved.
`COVER_SYSTEM_LBE_EFFECTIVENESS`	`20`	Visibility penalty for bulky equipment.
`COVER_SYSTEM_TREE_EFFECTIVENESS`	`15`	Vision degradation through trees/rocks.
`COVER_SYSTEM_STEALTH_TRAIT_VALUE`	`15`	Stealth points per level of the old-system Stealthy trait.
`COVER_SYSTEM_ADDITIONAL_TILE_PROPERTIES`	`TRUE`	Use per-tile XML properties for camo, stealth and sound (see below).
`COVER_SYSTEM_ALTERNATE_MULTI_TERRAIN_CAMO_CALCULATION`	`TRUE`	Treat tile camo affinities as caps, so mixed camo can be perfect on mixed terrain.
`COVER_SYSTEM_STATIC_SHADOWS_DECREASE_BRIGHTNESS`	`TRUE`	Standing in a building's shadow genuinely makes you darker.
`COVER_TOOLTIP_DISPLAY_DETAILED_TILE_PROPERTIES`	`TRUE`	The `F` tooltip lists detailed tile properties.
`COVER_SYSTEM_UPDATE_DELAY`	`500`	Refresh interval (ms) of the toggled cover overlay.

Camouflage¶

Four camo types, matched to terrain¶

Every item in Items.xml can carry up to four camouflage percentages — <CamoBonus> (woodland/jungle), <UrbanCamoBonus>, <DesertCamoBonus> and <SnowCamoBonus>. Your merc's total in each type is compared against the ground they are standing on:

Camo type	Item tag	Hides you on
Woodland ("jungle")	`<CamoBonus>`	Grass (low and high)
Urban	`<UrbanCamoBonus>`	Indoor floors, paved roads
Desert	`<DesertCamoBonus>`	Dirt roads, train tracks
Snow	`<SnowCamoBonus>`	Only via tile properties (below)

Plain flat ground counts the better of your woodland and desert camo. This classic terrain-type table is the fallback; with COVER_SYSTEM_ADDITIONAL_TILE_PROPERTIES = TRUE (the default) the engine instead reads per-tile camo affinities that tilesets can define in XML files (placed in \tilesets\AdditionalProperties\, per the INI's own documentation) — including snow, which has no terrain type of its own. With the (default-on) alternate multi-terrain calculation, those affinities act as caps rather than multipliers, so on mixed terrain a mix of camo types can add up to perfect concealment.

How much camo helps depends on stance: it works at full strength prone, at roughly two-thirds crouched, and at only about a tenth standing. At default settings a merc with 100% woodland camo lying prone in grass cuts the enemy's effective sight range by up to 80% — snipers in ghillie suits are genuinely hard to find.

Camo from clothing and gear¶

Most of your camouflage comes from what you wear. Armor, helmets, pants and load-bearing gear with camo values all count (the calculation checks your worn armor slots and all LBE slots), and even a camouflaged gun counts while it is in your hands or on the gun sling. Worn camo from equipment is capped at 100 − CAMO_KIT_USABLE_AREA (95% by default). Some current examples from Items.xml:

Item	Camo
Ghillie Suit	50% woodland
Ghillie Jacket / Pants / Leggings	40% / 30% / 30% woodland
Recon and Field Operative vests	25% woodland
German Flecktarn Vest	25% woodland

Gear can also work against you: shiny or bulky items such as the Rocket Rifle carry negative camo values on all four types.

Camo kits¶

Three camouflage kits exist in the current game data — Wood, Urban and Desert Camouflage Kit (there is no snow kit). Each provides 100% concentration of its type. To apply one, use it on a merc like any other consumable: click the kit onto the merc in the inventory panel (you can also apply it to an adjacent merc). Applying camo costs 40 AP in combat (AP_CAMOFLAGE in APBPConstants.ini).

Paint is deliberately weak in current 1.13: a kit only covers the face and hands — CAMO_KIT_USABLE_AREA = 5 in [Tactical Gameplay Settings] means at most 5% of the body, so kits top up clothing camo to 100% rather than replace it. (Old guides that promise 100% camo from a kit alone describe older builds; raise the INI value toward 100 if you want that back.) All applied paint shares that 5%: with CAMO_REMOVING = TRUE (default), applying a different kit repaints over the old type, and using a Rag on a merc wipes all paint off for half the AP cost.

Kit camo also washes off: each tile of deep water removes 1% (a Survival merc loses it 75% slower per trait level, and under the old trait system Camouflaged mercs don't lose it at all). Worn camo from clothing never washes off. Note that enemy soldiers who spawn carrying a camo kit may start the battle camouflaged themselves.

Seeing your camo

With SHOW_CAMOUFLAGE_FACES = TRUE ([Tactical Interface Settings]) portraits switch to a camouflaged version when a face exists in the matching Data\Faces\...CAMO folder. On the tactical map a soldier's sprite is only repainted once their total camo is high (the code comments put the threshold at 50%), so don't panic if a lightly painted merc still looks plain — the bonus works regardless.

The stealth stat¶

Separate from camouflage, items can carry a <StealthBonus>. Stealth works on any terrain but scales with darkness instead: at 100 stealth you reduce the enemy's sight range by up to COVER_SYSTEM_STEALTH_EFFECTIVENESS (50%) in the dark, and by much less in daylight. Stealth also feeds into how quietly you move (below) — as the source puts it, the stealth bonus "also affects noise made by characters walking".

Stealth comes from dedicated gear — the Stealth Ops set in current data gives 25% (vest), 15% (leggings) and 10% (helmet) — from the Stealthy trait (+25 with the new trait system) and from some IMP backgrounds. Heavy add-ons work against it: ceramic plates, titanium plating and hard helmets all carry small negative stealth values.

Stealth mode (sneaking)¶

Toggle stealth mode with Z (whole squad: Alt+Z; also the 4th mouse button). In real time you can additionally enable sneak-movement with the real-time stealth keys — all listed on the hotkeys page, so they are not repeated here. Sneaking costs extra AP per tile; the payoff is silence.

Under the hood every tile you sneak across rolls against a stealth skill of 20 + 4 × level + 0.4 × agility, improved by the Stealthy trait and half your worn stealth gear — and 1.13 grants a failed roll a second chance. Success means that tile made no noise at all. The roll gets harder when your effective health or energy is below 50%, in water (−10%, deep water −20%), and on noisy surfaces when tile properties are active (gravel betrays you; grass forgives you).

The Stealthy trait ([Stealthy] in Skills_Settings.INI) is the specialist's pick:

Setting	Default	Effect
`STEALTH_MODE_SPEED_BONUS`	`50`	The AP surcharge for sneaking is halved.
`BONUS_TO_MOVE_STEALTHILY`	`40`	Bonus to the per-tile silence roll.
`STEALTH_BONUS`	`25`	Added to overall stealth (better concealment).
`REDUCED_CHANCE_TO_BE_INTERRUPTED`	`20`	With the Improved Interrupt System.
`CHANCE_TO_BE_SPOTTED_FOR_MOVING_REDUCTION`	`25`	Movement visibility penalty reduced.

Noise and hearing¶

Everything you do has a volume, and every enemy in hearing range reacts. Moving normally generates noise each tile — crawling is the quietest, running the loudest, and water splashing louder still. Gunfire is the big one: suppressors cut a weapon's noise dramatically (and flash suppressors remove the muzzle flash that gives your position away at night) — see attachments. Purely cosmetically, MAX_PERCENT_NOISE_SILENCED_SOUND = 35 in [Sound Settings] decides below which remaining noise level the game plays the "silenced" sound effect.

Hearing works both ways. Weather muffles it for everyone — HEARING_REDUCTION_RAIN = 0.3 up to HEARING_REDUCTION_THUNDERSTORM = 0.8 in [Tactical Weather Settings]; a thunderstorm is a gift to knife-wielding mercs (see environment). The Night Ops trait sharpens your own senses ([Night Ops] in Skills_Settings.INI):

Setting	Default	Effect
`SIGHT_RANGE_BONUS_IN_DARK`	`1`	Extra sight range in darkness.
`BASIC_HEARING_RANGE_BONUS`	`1`	Extra hearing range, always.
`ONTOP_HEARING_RANGE_BONUS_IN_DARK`	`2`	Additional hearing range in dark places.
`INTERRUPTS_BONUS_IN_DARK`	`2`	Better interrupt chances at night.
`NEED_FOR_SLEEP_REDUCTION`	`3`	Stays fresh on the night shift longer.

Night operations¶

Night is the stealth player's home ground: at normal night light everyone's sight drops to 43% of its day value, your stealth stat works at full strength, and movement penalties fade. The classic 1.13 night raid — prone, camouflaged, suppressed weapons, Night Ops mercs — dismantles garrisons many times its size.

Gear decides who owns the dark. Current Items.xml values:

Item	Night sight	Day sight	Bright light
Night Vision Goggles, Gen. I	+10	−20	−40
Night Vision Goggles, Gen. II	+20	−20	−40
Night Vision Goggles, Gen. III	+30	−20	−40
Night Vision Goggles, Gen. IV	+40	−20	−40
Sun Goggles	−10	+10	+20

Vanilla's single "UV Goggles" item no longer exists — 1.13 replaced it with the four NVG generations. Many scopes also carry night-vision bonuses (the PSO series and the 7x Battle Scope, for example). Use the goggle-swap hotkeys (Shift+N and friends — see hotkeys) to switch the whole sector's eyewear between day and night gear; SMART_GOGGLE_SWAP and GOGGLE_SWAP_AFFECTS_ALL_MERCS_IN_SECTOR in [Tactical Interface Settings] tune the behavior.

Light discipline

Note the −40 bright-light penalty on all NVGs: flares, break lights, burning vehicles and flashlights blind night-vision users — yours and theirs. Firing an unsuppressed, unshrouded weapon at night paints a muzzle flash on your position, and walking through a lit area throws away every bonus in this section. Enemies at night carry (and drop) night gear too, increasingly so at higher difficulty and progress — see Know your enemy.

Camouflage is not a disguise¶

Camouflage and covert ops solve different problems. Camouflage makes enemies fail to see you; a disguise makes them see you and ignore you. The two actively exclude each other: a merc wearing any camouflaged clothing cannot pass as a civilian — the game checks your worn camo of all four types before letting you dress down. Strip the flecktarn before sending your spy in.

Sources¶

Data-1.13\Ja2_Options.INI ([Tactical Cover System Settings], [Tactical Gameplay Settings], [Tactical Interface Settings], [Tactical Vision Settings], [Sound Settings], [Tactical Weather Settings]), Data-1.13\Skills_Settings.INI ([Stealthy], [Night Ops], [Survival]), Data-1.13\APBPConstants.ini and Data-1.13\TableData\Items\Items.xml, all from the 1dot13/gamedir repository (current master)
Current source code from 1dot13/source: Tactical/LOS.cpp (sight adjustments, camo/terrain matching, stealth and brightness scaling), Tactical/opplist.cpp (MovementNoise), Tactical/Items.cpp (ApplyCamo, GetWornStealth, water wash-off), Tactical/Soldier Control.cpp (camo kit area caps, item application, LooksLikeACivilian), Tactical/Soldier Create.cpp (camouflaged enemy spawns)
"Help with camo" — Bear's Pit thread on CAMO_KIT_USABLE_AREA behavior (DepressivesBrot, silversurfer, townltu, 2018), cross-checked against current code
Hotkeys & controls on this site (r9389 hotkey reference) for all key references