Engine variables

Entity scripts keep their state in variable. (v.) names, which a client entity’s initialize and pre_animation scripts and its animations assign. Observed · the vanilla resource pack of bedrock-samples v1.26.60.5 Some names are read and never assigned by any script: the engine sets them. Inferred No published list names them, and what each holds is known only from how the vanilla scripts use it. Observed · the vanilla resource pack of bedrock-samples v1.26.60.5

Census

Over the 4,961 JSON files of the vanilla resource pack, 579 variable names are read and 436 are assigned somewhere (v.name =, not ==); 151 are read and never assigned. Proven · every JSON file of the v1.26.60.5 resource pack, the 182 files that are not strict JSON scanned as text Of the 151, the particle ones (particle_age, particle_lifetime, particle_random_1 to 4, emitter_age, emitter_random_1 to 3 and similar) are set by the particle system for each particle and emitter. Inferred The rest are the entity variables below, and a few that are a single entity’s alone (historical_frame_0 to 23 of the ender dragon, the minecart’s rail_offset and rail_rotation). Observed · the vanilla resource pack of bedrock-samples v1.26.60.5

variable.is_holding_right is assigned only by the player’s initialize (variable.is_holding_right = 0.0;), and read by the same animations as is_holding_left, which nothing assigns. Observed · the vanilla resource pack of bedrock-samples v1.26.60.5 The engine sets it like the left-hand one, the initial value being a default. Inferred

A name another entity assigns is outside the census but can still be the engine’s for one that never does. variable.state is assigned by the parrot’s and the creaking’s own scripts, but the cat’s and the ocelot’s movement controllers read it and neither entity’s files assign it. Observed · the vanilla resource pack of bedrock-samples v1.26.60.5 The cat’s controller.animation.cat.move goes to sneaking at 0, sprinting at 1, sitting at 2, walking at 3 and lie_down at 4. Observed · the vanilla resource pack of bedrock-samples v1.26.60.5 The engine sets it to the cat’s current posture by those numbers. Inferred

The entity variables

Each meaning below is taken from how the vanilla scripts use the variable; the usage column quotes the vanilla data. Observed · the vanilla resource pack of bedrock-samples v1.26.60.5

Variable	Vanilla usage	Taken to mean	Confidence
gliding_speed_value	walk cycles divide by it: cos(q.modified_distance_moved * 38.17) * q.modified_move_speed / v.gliding_speed_value	1, larger while gliding, slowing the limb swing; a script that reads it with nothing set divides by zero	Inferred
attack_time	attack animations and controllers: v.attack_time >= 0.0, sin((1 - v.attack_time) * 180)	the swing’s progress, 0 to 1	Inferred
is_first_person	selects the player’s first_person controller states and render controllers	the player is seen from its own eyes	Inferred
is_paperdoll	selects the player’s paperdoll state; the cape shows when !v.is_first_person || v.is_paperdoll	the entity is drawn as the inventory screen’s figure	Inferred
map_face_icon	hides the player’s third-person render controller, selects its map_player state	the entity is drawn as a map’s face icon	Inferred
is_holding_left, is_holding_right	arm poses: v.is_holding_left ? (-this * 0.5 - 18.0) : 0.0	the hand holds an item	Inferred
is_brandishing_spear	the drowned’s and player’s brandish_spear states	a trident is raised to throw	Inferred
is_holding_spyglass, is_tooting_goat_horn, is_using_brush	each stops the player’s arm bob and turns an arm pose	the item of that name is in use	Inferred
damage_nearby_mobs	the drowned’s and player’s damage_nearby_mobs states	a riptide spin attack	Inferred
is_sneaking	q.target_x_rotation - 105 - (v.is_sneaking ? 15 : 0) in humanoid arm poses	the entity sneaks	Inferred
swim_amount	the drowned’s swimming state: v.swim_amount > 0.0	how far into the swimming pose, 0 to 1	Inferred
player_x_rotation	read in the player’s scripts	the player’s view pitch	Inferred
use_item_interval_progress, use_item_startup_progress	the drowned’s and player’s use_item_progress state when either is above 0, whose animation.humanoid.use_item_progress turns the right arm by startup * (-60, -22.5, -5.625) + interval * 11.25 on each axis	the progress of an item being used, by phase: a wind-up that raises the arm, then a repeating interval that shakes it	Inferred
is_enchanted	eight render controllers (item default, bow, crossbow, shield and four armour ones) choose variable.is_enchanted ? material.enchanted : material.default, the enchanted materials being glint ones (entity_alphatest_glint)	the item drawn has the enchantment glint	Inferred
player_arm_height	first-person swap animations: arm position y = -10 * (1 - v.player_arm_height)	how far the main hand is raised as an item is swapped, 0 lowered to 1 raised	Inferred
bob_animation	gates the player’s first_person_walk state, which moves the held item by v.bob_animation * sin(q.life_time * 45) * 0.5	whether the held item bobs	Unknown
first_person_item_rotation_factor	first-person attack swings, where the third-person ones use first_person_rotation_factor (which the player computes as sin((1 - v.attack_time) * 180))	a scale on the first-person swing	Unknown
short_arm_offset_left, short_arm_offset_right	added to first-person arm positions	an offset for the arm’s length	Unknown
is_using_vr, is_horizontal_splitscreen, is_vertical_splitscreen	small corrections to first-person arm poses (95.0 + v.is_using_vr * 7.5)	the display mode	Inferred
fp_melee_spear_*, tp_melee_spear_*	the player’s and the spear’s melee animations; the player declares four of them public. The zombie, husk, zombie villager, piglin and zombified piglin assign the third-person ones themselves in pre_animation, from the spear’s kinetic timings and v.item_use_duration; for the player no script does	the spear’s melee motion, first and third person; for the player, the engine’s own computation	Unknown
liedownamount, liedownamounttail, lieonplayer	the cat’s lying-down animations	the cat’s lie-down progress, and whether it lies on a sleeping player	Inferred
animationamount, animationamountprev	the fishes’ swim animations, blended by q.frame_alpha	the swim cycle this tick and last	Inferred

The local player’s first-person animations also read one context value, c.player_offhand_arm_height, in the off hand’s swap animation where the main hand’s reads v.player_arm_height. Observed · the vanilla resource pack of bedrock-samples v1.26.60.5 It is the off hand’s raise, 0 to 1. Inferred See first-person player.

What do bob_animation, short_arm_offset_* and first_person_item_rotation_factor hold?

Their usage does not pin them down: bob_animation could be the view-bobbing setting or whether the player walks, and the arm offsets could depend on the skin’s arm width.