`data/damage_formulas/`

A damage formula: how a hit’s base amount becomes the damage dealt, from the attacker’s and victim’s stats. The world’s default_formula (the gameplay config) applies unless a damage type names its own. Basic is armour and per-element resistance with an optional critical roll; Expression writes the attacker’s and the victim’s parts as numbers. The engine declares manifold:basic.


Registry	`manifold:damage-formula`
Files	`data/damage_formulas/.ron`, `.update.ron`, `*.final.ron`
Sides	both: the server and every client load it, and the handshake’s data hash covers it
Reads	`manifold:predicate`
Contract	Gameplay framework, data stage

Entry

A record, written DamageFormula(..); the name before the parentheses is optional.

Field	Type	Required	Default	Description
`id`	`string`	yes		The formula’s key, `<mod-id>:<name>`.
`kind`	`FormulaKind`	yes		The formula.

Example

From game/flagship-game/data/damage_formulas/skyblock.ron:

DamageFormula(
    id: "flagship-game:skyblock",
    kind: Expression(
        gather: "(5 + q.stat('attacker', 'flagship-game:weapon_damage'))
                 * (1 + q.stat('attacker', 'flagship-game:strength') / 100)
                 * (1 + q.stat('attacker', 'flagship-game:damage_additive') / 100)",
        crit: Some((chance: "q.stat('attacker', 'flagship-game:crit_chance') / 100",
                    multiplier: "1 + q.stat('attacker', 'flagship-game:crit_damage') / 100")),
        mitigate: "v.damage_amount * 100 / (100 + q.stat('this', 'flagship-game:armor'))",
    ),
)

Types

`FormulaKind`

A damage formula’s kind.

Variant	Written	Description
`Basic`	`Basic(armor_stat: .., armor_constant: .., resist_cap: .., crit: ..)`	The amount is the base, then a critical roll, then armour (`k / (k + armor)`) and each element’s resistance.
`Expression`	`Expression(gather: .., crit: .., mitigate: ..)`	The formula as numbers in the `damage` context.

Basic fields:

Field	Type	Required	Default	Description
`armor_stat`	`string` or `None`	no	no armour	The victim’s armour stat (`manifold:stat` key).
`armor_constant`	`f32`	no	`100`	The armour constant `k`.
`resist_cap`	`f32`	no	`0.75`	The largest fraction a resistance removes.
`crit`	`Crit` or `None`	no	none	A critical roll.

Expression fields:

Field	Type	Required	Default	Description
`gather`	`number`	yes		The attacker’s part, run once on the hit’s total, with `v.damage_amount` the base; the result is shared between the elements in proportion to their bases.
`crit`	`Crit` or `None`	no	none	A critical roll between the two parts.
`mitigate`	`number`	yes		The victim’s part, run per element, with `v.damage_amount` the gathered amount.

`Crit`

A critical roll: when a draw is below chance, the amount is multiplied by multiplier and the hit carries manifold:hit.critical.

A record: Crit(..) or (..).

Field	Type	Required	Default	Description
`chance`	`number`	yes		The chance, 0 to 1.
`multiplier`	`number`	yes		The multiplier.

Value forms used here: number.

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data/damage_formulas/