Valhalla Vehicle Climbing Assist

Valhalla — Vehicle Climbing Assist and Low-Gear System

Source-verified 2026-06-21 against then-current master cf2a6d6a4; later branch-intel notes below name exact refs for current-head claims. Paths relative to Missions/[55-2hc]warfarev2_073v48co.chernarus/ unless noted. Arma 2 OA 1.64.

The Valhalla module is a client-side velocity-boost system that assists player-driven and AI-driven vehicles over steep terrain. It applies a progressive speed multiplier when the vehicle is already moving forward but too slowly — it does not cap top speed and does not brake above the target assist speed. Current stable master (includes commit 63e6b4142) keeps player actions for Tank, Car, and the AN-2 (An2_TK_EP1, Air class) vehicles. The AN-2 low-gear actions were added at Common/Init/Init_Unit.sqf:115-118; see Branch Intel below for the merge history.

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Branch Intel - AN-2 Fast-Lift Candidate

New upstream-mining branch origin/claude/upstream-an2-climb-boost@63e6b4142 is a small branch-only candidate, not current stable behavior. Its merge-base with current stable is be2bbd084, which is an ancestor of origin/master@f8a76de34; direct diffs against current stable also include B74.1 Init_CommonConstants.sqf:914-920 player-stats drift, so porting this branch must preserve current WFBE_C_STATS_ENABLED = true.

Ref	Payload	Status
Current stable (includes commit 63e6b4142)	Both maintained roots have an Air target block at Func_Client_LowGear.sqf:68-75 (_min = 100) and AN-2 Low Gear On/Off actions at Init_Unit.sqf:115-118.	Merged to master — this is now stable behavior, not branch-only.
origin/claude/upstream-an2-climb-boost@63e6b4142	Against merge-base be2bbd084, payload is four files / +32 / -2 and git diff --check is clean. Both maintained roots add an Air target of _min = 100 at Func_Client_LowGear.sqf:68-75 and add An2_TK_EP1 low-gear on/off actions at Init_Unit.sqf:87-90 without adding the Flip action.	Branch-only candidate. Smoke AN-2 takeoff/climb with low gear off/on, heavy load, runway departure, normal cruise speed, action visibility and maintained Vanilla parity before promotion.

Bootstrap Sequence

Step	Where	Source
Init_Valhalla.sqf called (spawned)	Init_Client.sqf:1075	Runs during client init; compiles VALHALLA_FNC_LowGear and installs the key EHs
Func_Client_AI_LowGear_Manager.sqf spawned	Init_Client.sqf:968	Separate [] spawn at end of client init; runs for the full session
Profile variable read	Client/Init/Init_ProfileVariables.sqf:27-34	WFBE_HIGH_CLIMBING_DEFAULT_ENABLED loaded from profileNamespace before Valhalla init

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Key Tracking (Init_Valhalla.sqf)

Init_Valhalla.sqf binds two display-level event handlers on display 46 (the main game display):

(findDisplay 46) displayAddEventHandler ["KeyDown", "_this call VALHALLA_FNC_HandleLowGearKeyDown"];
(findDisplay 46) displayAddEventHandler ["KeyUp", "_this call VALHALLA_FNC_HandleLowGearKeyUp"];

Init_Valhalla.sqf:57-58

The tracked keys are the union of three action-key arrays resolved at startup:

Local_HighClimbingForwardActionKeys =
    (actionKeys "carForward") +
    (actionKeys "carFastForward") +
    (actionKeys "carSlowForward");

Init_Valhalla.sqf:15-18

KeyDown pushes a matching key into Local_HighClimbingForwardKeys and sets Local_KeyPressedForward = true. Init_Valhalla.sqf:34-38

KeyUp removes the key from the list and resets Local_KeyPressedForward to count Local_HighClimbingForwardKeys > 0, so multi-key holds are handled correctly. Init_Valhalla.sqf:49-52

State locals initialised by Init_Valhalla.sqf:

Local variable	Initial value	Purpose
Local_HighClimbingModeOn	false	Whether climb assist is currently active
Local_HighClimbingRunning	false	Re-entry guard for the boost loop
Local_KeyPressedForward	false	Forward key currently held
Local_HighClimbingForwardKeys	[]	List of currently held forward keys

Init_Valhalla.sqf:12-14,19

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Profile Persistence (WFBE_HighClimbingDefaultEnabled)

WFBE_HighClimbingDefaultEnabled / WFBE_HIGH_CLIMBING_DEFAULT_ENABLED is the player's saved preference for whether newly-entered vehicles start with climb assist enabled.

Location	Behaviour	Source
Init_ProfileVariables.sqf:27-34	Loaded from profileNamespace into missionNamespace as WFBE_HighClimbingDefaultEnabled; defaults to false if absent or wrong type	Client init, before Valhalla
Init_Valhalla.sqf:6-11	Secondary nil-guard: if WFBE_HighClimbingDefaultEnabled is not yet defined, reads it again from profileNamespace	Runs slightly later than Init_ProfileVariables.sqf; guard is defensive
GUI_Menu_Team.sqf:14-17	Button label reflects current value on dialog open	Client/GUI/GUI_Menu_Team.sqf
GUI_Menu_Team.sqf:164-181	MenuAction == 14 toggles the value, updates missionNamespace, updates button label, and persists via WFBE_CO_FNC_SetProfileVariable if available, otherwise direct profileNamespace setVariable + saveProfileNamespace	Client/GUI/GUI_Menu_Team.sqf

The preference toggle is in the Team Menu (dialog idd 13000), button idc 13020, localised as STR_WF_TEAM_HighClimbingDefaultOn / STR_WF_TEAM_HighClimbingDefaultOff.

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Per-Vehicle Flag (WFBE_HighClimbingEnabled)

Each eligible vehicle carries a broadcast variable that gates the boost loop:

Detail	Value	Source
Variable name	WFBE_HighClimbingEnabled	Func_Client_LowGear.sqf:71, LowGear_Toggle.sqf:11
Scope	setVariable [name, value, true] — broadcast to all machines	LowGear_Toggle.sqf:13, Func_Client_AI_LowGear_Manager.sqf:34
Default when unset on a Tank or Car	Value of WFBE_HighClimbingDefaultEnabled	Func_Client_AI_LowGear_Manager.sqf:21-34
Default for all other vehicle classes	false (not assigned)	Func_Client_AI_LowGear_Manager.sqf:21-34

LowGear_Toggle.sqf is the per-vehicle runtime toggle. It flips WFBE_HighClimbingEnabled on the vehicle, broadcasts it, and if the local player is the driver it updates Local_HighClimbingModeOn and spawns the boost loop if needed. LowGear_Toggle.sqf:1-21

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Player Boost Loop (Func_Client_LowGear.sqf)

Spawned against the vehicle object (_vehicle spawn VALHALLA_FNC_LowGear). Protected by a re-entry guard on Local_HighClimbingRunning.

Loop exit condition — any of the following ends the loop:

• player != driver _vehicle
• !Local_HighClimbingModeOn
• !(_vehicle getVariable ["WFBE_HighClimbingEnabled", false])
• !canMove _vehicle

Func_Client_LowGear.sqf:77-81

Speed parameters:

Parameter	Cars	Tanks	Source
_min — target assist speed (km/h)	40	30	Func_Client_LowGear.sqf:52,65
_minBoostSpeed — minimum speed before boost is applied	1	1	Func_Client_LowGear.sqf:56

Boost coefficient curve:

Coefficient	Value	Source
_baseBoostCoef (applied near _min)	1.05	Func_Client_LowGear.sqf:60
_maxBoostCoef (applied near 0 km/h)	1.30	Func_Client_LowGear.sqf:61

The multiplier is interpolated linearly between _baseBoostCoef and _maxBoostCoef based on how far below _min the current speed is:

_boostCoef = _baseBoostCoef + (((_min - _speed) / _min) * (_maxBoostCoef - _baseBoostCoef));
if (_boostCoef > _maxBoostCoef) then {_boostCoef = _maxBoostCoef};

Func_Client_LowGear.sqf:88-89

Boost is only applied when ALL conditions hold: Local_KeyPressedForward, engine on, _speed > _minBoostSpeed, _speed < _min, and velocity direction within 15 degrees of vehicle heading. Func_Client_LowGear.sqf:78-99

The Z component of velocity is not modified — vertical movement is unaffected. Func_Client_LowGear.sqf:91-95

Loop sleep interval: 0.1 seconds. Func_Client_LowGear.sqf:101

On exit, both Local_HighClimbingModeOn and Local_HighClimbingRunning are reset to false. Func_Client_LowGear.sqf:104-105

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AI Tank Manager (Func_Client_AI_LowGear_Manager.sqf)

A while {!gameOver} loop spawned once at client init (Init_Client.sqf:968). It runs on the owning client for all AI-driven tanks in the player's group.

Each iteration (every 5 seconds):

1. Checks the player's current vehicle: if the player is the driver of a Tank or Car and WFBE_HighClimbingEnabled is not yet set, assigns it from WFBE_HighClimbingDefaultEnabled and broadcasts it. Func_Client_AI_LowGear_Manager.sqf:21-34
2. If the player is driving and the flag is enabled and both !Local_HighClimbingModeOn and !Local_HighClimbingRunning, starts the boost loop. Func_Client_AI_LowGear_Manager.sqf:37
3. Iterates units group player: for every AI-driven Tank that is local and does not already have AI_LowGear_Running == true, spawns Common_AI_LowGear.sqf against that vehicle. Func_Client_AI_LowGear_Manager.sqf:47-69

Performance audit integration: the manager records a sample every iteration:

["ai_lowgear_manager", diag_tickTime - _perfStart, Format["groupUnits:%1;started:%2", _perfUnits, _perfStarted], "CLIENT"] Call PerformanceAudit_Record;

Func_Client_AI_LowGear_Manager.sqf:72-75

The record is conditional on PerformanceAuditEnabled (defaults true) and skipped if PerformanceAudit_Record is nil. The payload includes group unit count and count of low-gear scripts started that tick.

Scalability note: on a large group the manager spawns one Common_AI_LowGear.sqf script per un-assisted AI tank per iteration. Each spawned script self-terminates when the vehicle becomes null, is destroyed (!alive), can no longer move (!canMove), or is no longer local to this client; it does not rely on the manager to clean it up. AI_LowGear_Running is a re-entry guard only — it is not a live termination signal.

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AI Tank Boost Loop (Common_AI_LowGear.sqf)

Runs client-side on the machine that owns (is local to) the vehicle. Guards:

• Exits immediately if vehicle is null, not a Tank, or not local. Common_AI_LowGear.sqf:43-47
• Re-entry guard via AI_LowGear_Running vehicle variable (local-only, not broadcast). Common_AI_LowGear.sqf:50-51

Speed parameters (same curve as player variant, tank-specific values):

Parameter	Value	Source
_min	30 km/h	Common_AI_LowGear.sqf:72
_minBoostSpeed	3 km/h	Common_AI_LowGear.sqf:76
_baseBoostCoef	1.05	Common_AI_LowGear.sqf:80
_maxBoostCoef	1.30	Common_AI_LowGear.sqf:81

Additional AI-specific guards before applying boost:

Guard	Effect	Source
WFBE_HighClimbingEnabled on vehicle	If player crew is present, reads WFBE_HighClimbingEnabled from the vehicle; if no player crew, always true (AI tanks without a player crew are always assisted)	Common_AI_LowGear.sqf:103-107
!isPlayer _driver	Human-driven tanks are not boosted by this script	Common_AI_LowGear.sqf:96
!(stopped _driver)	No boost if AI driver is stopped	Common_AI_LowGear.sqf:112
!(_currentCommand in ["WAIT", "STOP"])	No boost during explicit hold orders	Common_AI_LowGear.sqf:112

Sleep delay is adaptive: 0.1 s when the engine is running and assist is enabled, 0.5 s otherwise. Common_AI_LowGear.sqf:98,141

On loop exit, AI_LowGear_Running is reset to false (local-only). Common_AI_LowGear.sqf:144

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Variable Summary

Variable	Namespace	Type	Purpose
WFBE_HIGH_CLIMBING_DEFAULT_ENABLED	profileNamespace	BOOL	Persisted player preference
WFBE_HighClimbingDefaultEnabled	missionNamespace	BOOL	Session copy of above
WFBE_HighClimbingEnabled	vehicle (broadcast)	BOOL	Per-vehicle climb-assist gate
AI_LowGear_Running	vehicle (local only)	BOOL	Re-entry guard for Common_AI_LowGear
Local_HighClimbingModeOn	missionNamespace (local)	BOOL	Boost loop active flag
Local_HighClimbingRunning	missionNamespace (local)	BOOL	Re-entry guard for player boost loop
Local_KeyPressedForward	missionNamespace (local)	BOOL	Forward key currently held
Local_HighClimbingForwardKeys	missionNamespace (local)	ARRAY	List of held forward-key codes
VALHALLA_FNC_LowGear	missionNamespace	CODE	Compiled player boost loop

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Continue Reading

• Modules-Atlas — inventory of all client modules including the one-line Valhalla entry this page expands
• Player-Vehicle-And-Travel-Actions-Reference — action-map route for adjacent vehicle scroll actions such as manual flip, Push, HALO, Cargo Eject and Taxi Reverse
• AI-Headless-And-Performance — broader context for client-side AI performance and the Performance Audit system that ai_lowgear_manager records into
• Faction-Unit-And-Vehicle-Roster-Catalog — which Tank and Car classnames exist per faction; determines which vehicles the climb assist is eligible for
• Variable-And-Naming-Conventions — WFBE_C_* / WFBE_UP_* / Local_* naming rules
• Client-UI-And-Server-Loop-Perf-Findings — performance findings relevant to the per-group polling loop in the AI manager