Affixes

An affix is a named bundle of stat modifiers whose values roll within ranges, such as “Sturdy” giving 10 to 30 extra health. Single items roll affixes as they drop from random loot, come out of crafting, or when a mod asks; what an item rolled stays with it, and the entity that wears it gets the modifiers. The affixes module holds the API.

Unstable: rolling affixes onto items needs the unstable feature and may change in any release (Stability). What an item rolled is kept as item data, so after a restart a roll on an item no load finds, such as one in a player’s inventory, stays aside. Defining affixes and reading what an item rolled are stable.

use enshwick::affixes::{AffixCraft, AffixDef, AffixLoot, Range, ItemRarity, RollRules};
use enshwick::content::categories::ItemCategoryMask;
use enshwick::loot::Source;
use enshwick::stats::{Op, builtin};

fn init(load: &mut enshwick::Load<'_>) -> Result<(), enshwick::Off> {
    let health = load.open_stat(builtin::HEALTH_MAX)?;
    let fire = load.open_stat(builtin::RESISTANCE_FIRE)?;
    load.define_affix(
        "sturdy",
        &AffixDef::new("affix.sturdy", ItemCategoryMask::EQUIPMENT)
            .with(Range::new(health, Op::Add, 10.0, 30.0).step(1.0)),
    )?;
    load.define_affix(
        "fireproof",
        &AffixDef::new("affix.fireproof", ItemCategoryMask::EQUIPMENT)
            .with(Range::new(fire, Op::Add, 0.05, 0.2).step(0.01))
            .rarity(ItemRarity::Rare)
            .weight(20)
            .group("element"),
    )?;
    // Half the armour bosses drop rolls one or two affixes.
    load.add_loot_affixes(AffixLoot::new(Source::bosses(), 0.5).count(1, 2))?;
    // A fifth of what players craft rolls one.
    load.add_craft_affixes(AffixCraft::new(0.2, RollRules::new(1, 1)))
}

Defining affixes

load.define_affix(name, &def) defines <mod>:<name> during init, on both sides, so clients can name what items rolled. An AffixDef holds:

Field	Means
text	the text key that names the affix, in the mod’s texts
ranges	each modifier’s stat, operation and range; Range::step rolls in steps
weight	how likely it rolls against the others, 100 by default
rarity	Common to Legendary; a roll may cap it
categories	the item categories it rolls on: EQUIPMENT (armour and rings), WEAPONS, TOOLS and the others
group	affixes of one group never roll together on an item

Every mod’s affixes form one pool, so a mod that only rolls loot can roll affixes another mod defines.

Rolling

A roll takes the pool’s affixes that fit the item’s category and rarity cap, draws the count, then each affix by weight among those left and not sharing a group with one taken, then its values. roll(&pool, category, rules, seed) is the same roll as a pure function: the same seed, category and pool give the same affixes, whatever order the pool comes in.

• load.add_loot_affixes(AffixLoot) rolls the items with an entity of their own (weapons, armour, tools) that random loot puts into containers the rule’s Source matches, each at the rule’s chance, right after the container rolls its loot.
• load.add_craft_affixes(AffixCraft) rolls the items that turn up in a player’s inventories within a second of their craft request.
• affixes.roll(item, rules, seed, once) rolls one item on purpose, from load.affixes(); once leaves an item that rolled before as it is.

An item rolls once: the rules above skip items that rolled before, even those that rolled nothing, and an item no affix fits is left unmarked. Rolls run on the server; the item’s category comes from the game’s item data, which the server has once a player has been online.

What an item rolled

The roll is part of the item’s ItemStats (affixes and rolled), kept as item data and sent to clients that run Enshwick. affixes.lines(item) lists what an item gives, a Line per modifier: its own first, then each affix’s, with the stat’s index for stats.info and the affix’s index for affixes.info, which names its text key and rarity. That is the hook for per-item tooltips on the client.

Testing

The fake loader rolls as the server does: give items a category with FakeHost::item_category, roll them with affixes.roll and a seed, and put them on an entity with loader.wear to see the stats.