actor

Actor definitions configure core AI behaviours, including which decisions they make and how, irrespective of the character's appearance or rank-specific alterations (which is what actor_variant is for).

Actor type definitions

There are 16 actor types. Each actor type maps to one of 13 unique actor type definitions which are hardcoded and contain a combination of basic settings and references to game code implementing the particular behaviours of that actor type. Some actor types use the same definition, like monitor and sentinel.

Each actor type definition has a unique way to decide on one of 14 actions. It is difficult to understand how exactly each actor type definition differs without extensive testing and/or reverse engineering. It's known that there is a lot of similarity between their code, but that Flood units are the most unique.

Name	Race	When to search at target	When to search pursuit	Pursuit controller	Swarm	Known behaviours
elite	covenant	always	not_when_group	`true`	`false`	...
jackal	covenant	never	never	`false`	`false`	...
grunt	covenant	always	always	`false`	`false`	Flees when Elite is killed. Cannot evade.
hunter	covenant	always	not_when_group	`true`	`false`	...
engineer	covenant	always	always	`false`	`false`	...
marine	human	never	never	`false`	`false`	Prefers to group together.
crew	human	always	always	`false`	`false`	...
flood	flood combat	always	always	`true`	`false`	Cannot throw grenades.
infection	flood infection	never	never	`false`	`true`	...
flood carrier	flood carrier	always	never	`true`	`false`	...
sentinel	sentinel	always	always	`false`	`false`	Cannot throw grenades.
mounted_weapon	none	never	never	`false`	`false`	...

Structure and fields

Field Type Comments

flags bitfield

Flag	Mask	Comments
can see in darkness	`0x1`
sneak uncovering target	`0x2`
sneak uncovering pursuit position	`0x4`
unused	`0x8`
shoot at targets last location	`0x10`	When no target is visible, briefly shoot at where the target was last seen.
try to stay still when crouched	`0x20`
crouch when not in combat	`0x40`
crouch when guarding	`0x80`
unused 1	`0x100`
must crouch to shoot	`0x200`
panic when surprised	`0x400`	When an enemy unit is newly detected within this actor's surprise distance, panic.
always charge at enemies	`0x800`	Always ignore other paramaters such as desired combat ranges and run at enemies.
gets in vehicles with player	`0x1000`
start firing before aligned	`0x2000`
standing must move forward	`0x4000`
crouching must move forward	`0x8000`
defensive crouch while charging	`0x10000`
use stalking behavior	`0x20000`
stalking freeze if exposed	`0x40000`
always berserk in attacking mode	`0x80000`
berserking uses panicked movement	`0x100000`
flying	`0x200000`
panicked by unopposable enemy	`0x400000`
crouch when hiding from unopposable	`0x800000`
always charge in attacking mode	`0x1000000`	When this actor's squad is in attacking mode, ignore other paramaters such as desired combat ranges and run straight at enemies.
dive off ledges	`0x2000000`	Will not attempt to avoid sheer drops when diving away from dangerous objects.
swarm	`0x4000000`
suicidal melee attack	`0x8000000`
cannot move while crouching	`0x10000000`
fixed crouch facing	`0x20000000`
crouch when in line of fire	`0x40000000`
avoid friends line of fire	`0x80000000`

more flags bitfield

Flag	Mask	Comments
avoid all enemy attack vectors	`0x1`
must stand to fire	`0x2`
must stop to fire	`0x4`
disallow vehicle combat	`0x8`
pathfinding ignores danger	`0x10`	Will not attempt to avoid live grenades, projectiles, environmental damage, etc when moving.
panic in groups	`0x20`
no corpse shooting	`0x40`

type

enum

This field acts as an index into an actor type definitions array where hardcoded actor behaviours are defined.

Option	Value	Comments
elite	`0x0`	Uses the elite actor type definition.
jackal	`0x1`	Uses the jackal actor type definition.
grunt	`0x2`	Uses the grunt actor type definition.
hunter	`0x3`	Uses the hunter actor type definition.
engineer	`0x4`	Uses the engineer actor type definition.
assassin	`0x5`	Uses the elite actor type definition (duplicate).
player	`0x6`	Uses the marine actor type definition (duplicate).
marine	`0x7`	Uses the marine actor type definition.
crew	`0x8`	Uses the crew actor type definition.
combat form	`0x9`	Uses the flood actor type definition.
infection form	`0xA`	Uses the infection actor type definition.
carrier form	`0xB`	Uses the flood carrier actor type definition.
monitor	`0xC`	Uses the sentinel actor type definition (duplicate).
sentinel	`0xD`	Uses the sentinel actor type definition.
none	`0xE`	Uses the grunt actor type definition.
mounted weapon	`0xF`	Uses the mounted_weapon actor type definition.

max vision distance

float

Unit: world units

Maximum range of sight.

central vision angle

float

Horizontal angle within which the actor sees targets out the the maximum range.

max vision angle

float

Maximum horizontal angle within which the actor sees targets at range.

peripheral vision angle

float

Maximum horizontal angle within which the actor sees targets "out of the corner of its eye" (Guerilla description).

peripheral distance

float

Unit: world units

standing gun offset Vector3D

Field	Type	Comments
i	`float`
j	`float`
k	`float`

crouching gun offset Vector3D^?

hearing distance

float

Unit: world units

notice projectile chance

float

Min: 0
Max: 1

notice vehicle chance

float

Min: 0
Max: 1

combat perception time

float

Unit: seconds

guard perception time

float

Unit: seconds

non combat perception time

float

Unit: seconds

inverse combat perception time

float

Cache only

inverse guard perception time

float

Cache only

inverse non combat perception time

float

Cache only

dive into cover chance

float

Min: 0
Max: 1

emerge from cover chance

float

Min: 0
Max: 1

dive from grenade chance

float

Min: 0
Max: 1

pathfinding radius

float

Unit: world units

glass ignorance chance

float

Min: 0
Max: 1

stationary movement dist

float

Unit: world units

free flying sidestep

float

Unit: world units

begin moving angle float

cosine begin moving angle

float

Cache only

maximum aiming deviation Vector2D

Field	Type	Comments
i	`float`
j	`float`

maximum looking deviation Vector2D^?

noncombat look delta l float

noncombat look delta r float

combat look delta l float

combat look delta r float

idle aiming range Vector2D^?

idle looking range Vector2D^?

event look time modifier Bounds

Field	Type	Comments
min	`float`
max	`float`

noncombat idle facing

Bounds^?

Unit: seconds

noncombat idle aiming

Bounds^?

Unit: seconds

noncombat idle looking

Bounds^?

Unit: seconds

guard idle facing

Bounds^?

Unit: seconds

guard idle aiming

Bounds^?

Unit: seconds

guard idle looking

Bounds^?

Unit: seconds

combat idle facing

Bounds^?

Unit: seconds

combat idle aiming

Bounds^?

Unit: seconds

combat idle looking

Bounds^?

Unit: seconds

cosine maximum aiming deviation

Vector2D^?

Cache only

cosine maximum looking deviation

Vector2D^?

Cache only

do not use

TagDependency: weapon

Unused

do not use 1

TagDependency: projectile

Unused

unreachable danger trigger enum

Option	Value	Comments
never	`0x0`
visible	`0x1`
shooting	`0x2`
shooting near us	`0x3`
damaging us	`0x4`
unused	`0x5`
unused1	`0x6`
unused2	`0x7`
unused3	`0x8`
unused4	`0x9`

vehicle danger trigger enum^?

player danger trigger enum^?

danger trigger time

Bounds^?

Unit: seconds

friends killed trigger int16

friends retreating trigger int16

retreat time

Bounds^?

Unit: seconds

cowering time

Bounds^?

Unit: seconds

friend killed panic chance

float

Min: 0
Max: 1

leader type enum^?

leader killed panic chance

float

Min: 0
Max: 1

panic damage threshold

float

Min: 0
Max: 1

surprise distance

float

Unit: world units

hide behind cover time

Bounds^?

Unit: seconds

hide target not visible time

float

Unit: seconds

hide shield fraction

float

Min: 0
Max: 1

attack shield fraction

float

Min: 0
Max: 1

pursue shield fraction

float

Min: 0
Max: 1

defensive crouch type enum

Option	Value	Comments
never	`0x0`
danger	`0x1`
low shields	`0x2`
hide behind shield	`0x3`
any target	`0x4`
flood shamble	`0x5`

attacking crouch threshold float

defending crouch threshold float

min stand time

float

Unit: seconds

min crouch time

float

Unit: seconds

defending hide time modifier float

attacking evasion threshold float

defending evasion threshold float

evasion seek cover chance

float

Min: 0
Max: 1

evasion delay time

float

Unit: seconds

max seek cover distance

float

Unit: world units

cover damage threshold

float

Min: 0
Max: 1

stalking discovery time

float

Unit: seconds

stalking max distance

float

Unit: world units

stationary facing angle float

change facing stand time

float

Unit: seconds

uncover delay time

Bounds^?

Unit: seconds

target search time

Bounds^?

Unit: seconds

pursuit position time

Bounds^?

Unit: seconds

num positions (coord)

uint16

Min: 0

num positions (normal)

uint16

Min: 0

melee attack delay

float

Unit: seconds

Minimum time between consecutive melee attempts.

melee fudge factor

float

Unit: world units

Determines where to start the melee animation:0 begins on top of the target, positive values begin in front of the target, negative values begin behind the target.

melee charge time

float

Unit: seconds

How long to chase a target to begin a melee attack before giving up.

melee leap range

Bounds^?

Unit: world units

melee leap velocity

float

Unit: world units per tick
Min: 0
Max: 1

melee leap chance

float

Min: 0
Max: 1

melee leap ballistic

float

Min: 0
Max: 1

berserk damage amount

float

Min: 0
Max: 1

When HP is below the berserk damage threshold, the actor may berserk when receiving any damage that deals this much of the actor's maximum HP in one tick.

berserk damage threshold

float