Expressions

Most places that require you to enter a value (when making Effects, most commonly) do so through the use of Expressions. These can be made up of regular numbers, addition, subtraction, multiplication, and division, in addition to the functions and variables listed below.

Functions

function	example	returns	explanation/usage
abs(x)	abs(-5)	5	The absolute value of the input value
atan2(x, y)	toDegrees(atan2(1, 1))	45	atan2 of the given x, y position. (Converts a vector into an angle in radians)
boolean(x)	boolean(5)	1	Returns 0 if the given expression evaluates to 0, 1 otherwise
ceil(x)	ceil(2.7)	3	Rounds up
floor(x)	floor(2.7)	2	Rounds down
round(x)	round(2.7)	3	Rounds to nearest
max(x, y, z...)	max(2, 3, 8, 6)	8	Returns the max of any number of parameters
min(x, y, z...)	min(2, 3, 8, 6)	2	Returns the min of any number of parameters
pow(x, e)	pow(2, 3)	8	Returns the first parameter to the power of the second parameter
sqrt(x)	sqrt(16)	4	Returns the square root
sin(x)	sin(3.14/2)	1
cos(x)	cos(3.14/2)	0
sign(x)	sign(5)	1	Returns the signum; zero if the argument is zero, 1 if the argument is greater than zero, -1 if the argument is less than zero.
smoothstep(x)	smoothstep(0.75)	0.84	Given a number between 0 and 1, returns that number put into the smoothstep function (x*x*(3-2*x))
smootherstep(x)	smootherstep(0.75)	0.89	Given a number between 0 and 1, returns that number put into the smootherstep function (x*x*x*(10+x*(6*x-15)))
isMatch(x, y, z...)	isMatch(5+2, 7)	1	Returns 1 if all given parameters equal the same value, 0 otherwise.
isMatchText(a, b...)	isMatchText(_PARAM_, value)	1	Returns 1 if all given parameters equal the same text string, 0 otherwise. (Useful for checking a parameter against another string)
length(x, y, [z])	length(5, 5)	7.071	Returns the length (magnitude) of a given Vector2 or Vector3
lerp(a, b, t)	lerp(0, 100, 0.8)	80	Linearly interpolates between a and b by t (where t is clamped to 0 - 1), where t=0 returns a, t=1 returns b, and t=0.5 returns a value 50% of the way from a to b, etc.
greaterThan(a, b)	greaterThan(5, 7)	0	Returns 1 if a is greater than b, 0 otherwise
lessThan(a, b)	lessThan(5, 7)	1	Returns 1 if a is less than b, 0 otherwise
between(x, min, max)	between(5+1, 2, 7)	1	Returns 1 if x is between min and max (or is equal to min or max), 0 otherwise
if(x, pass, fail)	if(1, 25, 30)	25	Returns pass value if x is non-zero, returns fail value otherwise (if fail value is omitted, will return 0 instead)
toDegrees(angle)	toDegrees(3.14/2)	89.95	Converts angle in radians to degrees
toRadians(angle)	toRadians(90)	1.57 (Approx. Pi/2)	Converts angle in degrees to radians

Variables

variable	example	returns	explanation/usage
EVENT_ROLL		A number between 1 and 100	Used in choice target tests, in the Chose Outcome, generally seen together with roll_one, roll_two, roll_three, etc. expressions
IS_FLANKING		1 if flanking, 0 otherwise	If this event contains attack info (e.g. a DAMAGE_ROLL, DAMAGE_ROLL_INCOMING, DAMAGE_ROLL_AFTER_ARMOR), returns whether or not the attack is flanking.
THIS_ASPECT		The integer value of this event's parent aspect	If this event has a parent aspect, returns the value of that aspect.
TOWN_POPULATION_LIMIT		The population limit for all towns (200)
RECRUIT_COST_ADJUSTMENT		-1 if company size < 3, 0 if >= 3, 1 if >= 6, 2 if >= 8, 3 if >= 10	Adjustment for recruit cost based on company size. This is used to make recruits cheaper if you have fewer of them, and more expensive if you have more.
RECRUIT_ENCOUNTER_SCORE_OFFSET		If chapter 1, returns 0.5 if company size=3, 2 if size=2, 4 if size=1. If chapter > 1, returns 0.5 if company size=4, 2 if size=3, 4 if size=2, 9 if size=1. Returns 0 otherwise.	An offset for recruit encounters that makes it so the encounter is more likely to happen if you have a smaller company. This is used in events that give you recruits.
isDefender	isDefender.hero	1 if the given role is the current defender of an AttackRoll Outcome, 0 otherwise	Generally used if you want different damage for one enemy in an attack than for others. (See how fireleash works, dealing half damage to defenders that aren't on the target tile)
RESOURCE	RESOURCE.legacyPoints	The amount of the given resource	Can be used to find the amount of any resource: legacyPoints, heartwoods, hides, ingots, fabrics, and spellthreads
COUNT	COUNT.target	How many matches were made for the given target	Often used in the effect.info.aiPriority field to make give AOE attacks higher priority if they hit more targets. Also used in the Damage Outcome for multi-target abilities, to divide stunt chance among the targets.
EXISTS	EXISTS.target	1 if at least one match was made for the given target, 0 otherwise
ASPECT_PARAM0	self.ASPECT_PARAM0.extraDamageAspect	The value of the nth parameter	Tries to get a parameter value from an aspect on a given role. This can be done for up to a 9th parameter (ASPECT_PARAM0, ASPECT_PARAM1, etc.)
ITEM_CATEGORY	weapon.ITEM_CATEGORY.bow	1 if the given item is of the given category (bow, sword, spear, etc), 0 otherwise
WEAPON_TIER	WEAPON_TIER.weapon	The tier of the given weapon, or -1 if there isn't one or it isn't a weapon
ITEM_TIER	item.ITEM_TIER	The tier of the given item, or -1 if there isn't one or it isn't an item
hasItem	hero.hasItem.spearBone	1 if the given role has (or is) an item with the given item id, 0 otherwise
canEquip	hero.canEquip.item	1 if the given role can equip the second role, 0 otherwise
TURN_NUMBER	TURN_NUMBER	The current mission turn number
SEASON	SEASON	The current season (1=Winter, 2=Spring, 3=Summer, 4=Fall)	Generally, you'll want to do something like isMatch(SEASON, 1) to check if it's Winter
YEAR	YEAR	The current year
DAY_OF_MONTH	DAY_OF_MONTH	day of the current season
distanceTo	target.distanceTo.targetTile	In a mission, the distance between two roles (can be entities or tiles)	Used to calculate the extra damage dealt from knockback attacks, and certain other edge cases like making sure the Thrixl Thrusk is still in range to attack again after its first attack (e.g. if the defender has Riposte and a knockback weapon)
ticksPerTurn		2	Used along with timeCostPerStep for movement abilities
SIZE	source.SIZE	Number of tiles a mission entity takes up, or its max footprint dimension	Used in Splinterblast to give larger objects greater AOE
AGE_IN_YEARS		The age of the current target.
MIN_ATTACK_RANGE	self.MIN_ATTACK_RANGE	The minimum range at which the given target can attack.	Used for movement abilities to determine whether to show the dotted-line attack suggestion.
MAX_ATTACK_RANGE	self.MAX_ATTACK_RANGE	The maximum range at which the given target can attack.	Used for movement abilities to determine whether to show the dotted-line attack suggestion.
MAX_MELEE_ATTACK_RANGE	self.MAX_MELEE_ATTACK_RANGE	The maximum range at which the given target can melee attack.	Used for guarding abilities to show range feedback.
POSITION_X	self.POSITION_X	The x position (tile) of the unit on the mission map
POSITION_Y	self.POSITION_Y	The y position (tile) of the unit on the mission map
maxValue	self.maxValue.gorgonCorruptedTileRel	The maximum value of any aspects the given target has starting with the given string
totalValue	self.totalValue.myParameterizedAspect	The total value of any aspects the given target has starting with the given string
HAS_FRIEND		1 if the current target has a friend, 0 otherwise	Used in events when we want to match a target that has a friend
HAS_LOVER		1 if the current target has a lover, 0 otherwise	Used in events when we want to match a target that has a lover
HAS_RIVAL		1 if the current target has a rival, 0 otherwise	Used in events when we want to match a target that has a rival
HAS_FAMILY		1 if the current target has family (a parent, child, grandparent, etc), 0 otherwise
HAS_PARENT		1 if the current target has a parent, 0 otherwise
HAS_CHILD		1 if the current target has a child, 0 otherwise
HAS_SIBLING		1 if the current target has a sibling, 0 otherwise
HAS_[relationship]_IN_PARTY	HAS_LOVER_IN_PARTY	"_IN_PARTY" can be added to any of the above, to specify that the related unit must be in the party role. 1 if there is such a unit, 0 otherwise	Useful for events that involve lovers, rivals, etc because we want to match a hero that has a valid lover first; if we match a hero with a lover not in the party first, the event will just fail and won't be picked
CAN_FORM_ROMANCE		1 if the current target can form a romance (no existing lover, no npc lover, not a skeleton, doesn't have random romances disabled), 0 otherwise
LEVEL	self.LEVEL	The level of the given hero target, or 0 if none	Generally used in abilities when we want the ability's power to scale with level
IS_LEGACY_HERO	self.IS_LEGACY_HERO	1 if the hero is a legacy hero, 0 otherwise
THREAT_STRENGTH	foes.THREAT_STRENGTH	The full "strength", or number of cards, of a threat	Used to show threat strength in attackSite blurb
THREAT_STRENGTH_FROM_INFESTATION		The strength being added to a threat from infested tiles
THREAT_STRENGTH_FROM_EXTRA_CHAPTER_CARDS		The strength being added to a threat from extra chapter cards, added during the interval
THREAT_STRENGTH_FROM_INCURSION_SIZE		The strength being added to a threat from the incursion size
THREAT_STRENGTH_BASE		The base threat strength, not including strength from infestations or extra chapter cards
THREAT_CALAMITIES	foes.THREAT_CALAMITIES	The number of calamity cards that have been drawn for the given threat. (Useful if you have an event that takes away a calamity, and you want to be sure it'll be able to)
THREAT_MONSTER_CARDS		number of monster cards in the mission
NUM_ENEMIES		The number of enemies in the current mission
MISSIONPLAN_HAS_TAG	MISSIONPLAN_HAS_TAG.forbidSpirits	1 if the current mission plan has the given tag, 0 otherwise	Currently used in Omenroad to determine if fights are boss fights or if spirits are forbidden
CHAPTER		chapter or dungeon page number
DIFFICULTY_COMBAT		combat difficulty (1-4)	Often useful along with if and isMatch functions, e.g. if(isMatch(DIFFICULTY_COMBAT,1),8) would return 8 on storyteller difficulty
DIFFICULTY_OVERLAND		overland difficulty (1-4)
IS_DUNGEONMODE		are we currently in dungeonmode (Omenroad)?
IS_DUNGEONMODE_CHALLENGE		are we currently in dungeonmode (Omenroad), and a challenge run (where peril and odes are enabled)?
SCENERY_ID	target.SCENERY_ID.ovenOn	1 if the scenery has the given id, 0 otherwise
OVERLAND_TILE_DISTANCE_TO_CLOSEST_HERO		Distance from this overland tile to the nearest hero	Specifically used when building a bridge or pass to an inaccessible tile, to decide where to build it
raw	raw.POTENCY	The raw stat (a float, not converted to an integer)
CAN_ROMANCE	CAN_ROMANCE.hook	1 if the current target can romance the given target, 0 otherwise	Must be mutually attracted, not already have lovers, and non-family
CAN_ROMANCE_LOOSE	CAN_ROMANCE_LOOSE.hook	1 if the current target can romance the given target, 0 otherwise	a looser check for romance. Checks family and forbidden romance (e.g. skeleton), but ignores existing relationships, forbidRandomRomances, and attraction
CAN_RIVAL	CAN_RIVAL.hook	1 if the current target can be rivals with the given target, 0 otherwise	Must not already have rivals
SHIP_WITH	SHIP_WITH.hook	The tier of the relationship between the current target and the given target	This can be any kind of relationship; lovers, rivals, or friends
FRIEND_WITH	FRIEND_WITH.hook	The tier of the friendship between the current target and the given target, 0 if not friends
LOVER_WITH	LOVER_WITH.hook	The tier of the romance between the current target and the given target, 0 if not lovers
RIVAL_WITH	RIVAL_WITH.hook	The tier of the rivalry between the current target and the given target, 0 if not rivals
FAMILY_WITH	FAMILY_WITH.hook	1 if the current target is family with the given target, 0 otherwise
PARENT_OF	PARENT_OF.hook	1 if the current target is the parent of the given target, 0 otherwise
CHILD_OF	CHILD_OF.hook	1 if the current target is the child of the given target, 0 otherwise
SIBLING_OF	SIBLING_OF.hook	1 if the current target is a sibling of the given target, 0 otherwise
NOT_FAMILY_WITH	NOT_FAMILY_WITH.hook	0 if the current target is family with the given target, 1 otherwise.	NOT_FAMILY_WITH.hook is equivalent to (1 - FAMILY_WITH.hook)
DLC_INSTALLED_ARMORSANDSKINS		1 if the player has the Armors and Skins DLC enabled, 0 otherwise
DLC_INSTALLED_OMENROAD		1 if the player has the Omenroad DLC enabled, 0 otherwise
MOD_ACTIVE.modId	MOD_ACTIVE.myCoolMod	1 if the mod with the given id is active	Useful if your mod has dependencies or differences based on other mods

Interpolation and Easing Functions

Two or more values can be interpolated between in the form of progress~{a|b|c|...} where progress is a value from 0-1, with 0 returning the starting value, 1 returning the final value, and anything in between interpolating between values. For example:

life~{0|0.5:0.9|1}
life~{10:0|20:1}
life~{0:0|inOutSine:10:1}

("life" is the most commonly used progress value, as this is commonly used for particle effects, but any value can be used, and this can be used for more than particles)

Each section can have up to two numbers and one easing function:

empty --> interpolate all values, no easing
## --> y value, interpolate x
##:## --> x, y, no easing
##:ease --> y, easing
ease --> easing function, interpolate x and y
ease:## --> easing and y, interpolate x
ease:##:## --> easing, x, y
##:ease:## --> x, easing, y
##:##:ease --> x, y, easing

For example, this expression could be used on the alpha channel in a SetColor particle rule: life~{0|0.1:1|0.9:0.5|0} Which would cause the particle to fade from invisible to fully visible in the first 1/10 of the particle's life, then fade to half visibility for most of its life, then at 90% of the way through its life, start fading back to invisible. (Adding easing functions to the expression could be useful to make the transitions look smoother)

The available easing functions are as follows, each having an in, out, and inOut version (e.g. inQuad, outQuad, inOutQuad)

none, Quad, Cubic, Quart, Quint, Circ, Sine, Expo, Back, Bounce, Elastic

Particle Variables

There are a number of variables that are specific to working with particles

variable	explanation/usage
Particles
life	Percent of the particle's life it has existed for (time/killTime)
time	How long (in seconds) this particle has existed for
killTime	The kill time of this particle
x/y/z	The x/y/z position of the particle relative to the emitter
vx/vy/vz	The x/y/z velocity of the particle
rotation	Particle sprite rotation in degrees
r/g/b/a	The red/green/blue/alpha color of the particle
size	The scale of the particle
particleNumber	What number particle this is (loops up to the emitter budget)
offset_V(x)	Get the data V from a different particle, whose particleNumber is at the given offset x. For example, offset_rotation(-1) would get the rotation of the previous particle. Can be useful for particle "chains", where you want each particle to face the previous one, etc. Note that a negative offset is usually a better choice, since a positive offset will be using data from 1 frame behind for the next particle
particleNumData_V(x)	Get the data V from a different particle, whose particleNumber is at the given number x. For example, offset_z(0) would get the z position of the first particle. In general, if you have one "main" particle you want other particles to act in response to, you may want to set an EmitterVar to store the particleNumber of the main particle, which can then be used for the number x
Emitter
e.life	Percent of the emitter's life it has existed for (e.time/emitter lifetime)
e.time	How long (in seconds) this emitter has been on this loop for (resets on loop)
e.totalTime	How long total (in seconds) this emitter has existed
e.position.x/y/z	Position1 x, y, and z
e.position2.x/y/z	Position2 x, y, and z
e.dx/dy/dz	Position offset between position 1 and 2 (e.position2.x - e.position.x, etc)
e.length	Distance between position1 and position2
e.budget/size	Number of particles this emitter is allotted
e.loopCounter	Number of loops this emitter has gone through
e.facingDirection	Returns 1 if position2 is to the right of position, returns -1 if it's to the left. Useful if you want to rotate something clockwise or counterclockwise depending on the direction it's used in, for example
Global
healthBarZ	The z position of the associated unit's healthbar (useful for making particles that go by a unit's head)
screenScale	UI scale, equal to 1 at a "default" scale. Useful for UI particles, which should often get bigger along with the UI.
UIGain	Equal to 0.48/exposure - Multiply by color to make a particle have a similarly appearing brightness on both dark and bright maps. Useful for in-world UI particles, which we want to be readable at all times.
thisScriptCount	Number of times this script is being used. Useful for reducing certain particles (like fire smoke) if there's a lot of it onscreen
tileIsVisible	Returns 1 if the tile at the particle's x,y position is visible to the player (not in fog of war), 0 otherwise. Useful for reducing particles in areas that are in fog of war, for performance reasons.
dt	Time (in seconds) since the last frame
ATTACK_COLOR.r/g/b	The highlight color used by attack abilities (default red, user customizable)
ATTACK_SECONDARY_COLOR.r/g/b	The highlight color used by secondary attack abilities (default orange, user customizable)
INTERACT_COLOR.r/g/b	The highlight color used by interact abilities (default blue, user customizable)