Vixen
caa30e12

Gameplay · guide

Items

A definition and a sixteen-byte instance, with every affix and every stat recomputed from a roll seed rather than stored.

Edit this page on GitHub

Documents

What it is#

An item definition is authored content: a name, a rarity, a slot, an item level, a stack size, a durability, sockets, a binding policy, tags, stats and the affix pools it rolls from. An item instance is one copy of it, and it is sixteen bytes: the definition, a roll seed, a stack count, a durability and a bound state.

Everything else — which affixes it rolled, what they gave, what the tooltip says — is recomputed from those sixteen bytes.

What it is for#

A bank of ten thousand items is a real number, and doc 28 § Items is explicit about the consequence: an instance carrying a materialised stat block is fifty times the memory for data that is a pure function of the seed.

It buys more than memory. Because the affixes are a function of (definition, seed), the wire carries a definition id and a seed, and a client's tooltip, a trade window and a realm's damage calculation agree without any of them being sent — or able to be lied to about — a stat block.

Using it#

Author the item, its rarity and its affix pools as .vxdef content; compile the catalog into an ItemLibrary once at load. ItemTemplate.Create makes a fresh instance; ItemAffixes.Roll recovers what a seed rolled; ItemStats.Compute produces the equip-time block as ordinary Modifiers, so an equipped sword is exactly as much a modifier source as a buff and comes off just as exactly.

⚠ The affix pool's order is part of what a seed means. It is sorted by address rather than by the order a designer listed it, so tidying a YAML file does not re-roll every sword in the game. Adding an affix to a pool *does* re-roll them, and there is no way around that — it is a content decision with a visible consequence.

⚠ Rarity is a definition, not an enum and not a tag. An enum fixes every game to one ladder; a tag sorts alphabetically, so a bag sorted by rarity would put Common above Legendary. A rarity needs a number. It carries a tag as well, so *every legendary drops a token* stays a tag query.

⚠ **Broken is zero durability; indestructible is zero *maximum* durability.** Two fields one word apart, and reading them the wrong way round makes every stack of ore in the game broken.

Examples#

Authoring an item, near enough doc 28's own example:

yaml
# Assets/Items/flamebrand.vxitem!ItemDefinitiondisplayName: Flamebrandrarity: rarities/legendaryslot: Item.Slot.MainHanditemLevel: 80maximumDurability: 100sockets: 2binding: OnEquiptags: [ Item.Weapon.Sword, Item.Source.Raid ]stats:  - { attribute: Power, op: Add, value: 251 }  - { attribute: Precision, op: Add, value: 179 }affixPools: [ affixes/pools/weapon ]icon: icons/flamebrandprefab: prefabs/weapons/flamebrand

Making one, and reading back what its seed rolled:

csharp
using System.Collections.Generic;using Vixen.Gameplay;using Vixen.Gameplay.Items;static class Drops {    public static ItemInstance Flamebrand(ItemLibrary items, uint seed) =>        items.Get(DefId.From("items/flamebrand")).Create(stack: 1, seed: seed);    public static IEnumerable<string> Affixes(ItemLibrary items, ItemInstance instance) {        var template = items.Get(instance.Definition);        foreach (var rolled in ItemAffixes.Roll(template, instance.Seed)) {            yield return items.FindAffix(rolled.Affix)!.Definition.DisplayName;        }    }}

Equipping one, which is just a set of modifiers:

csharp
using System.Collections.Generic;using Vixen.Gameplay;using Vixen.Gameplay.Items;static class Equipping {    public static void Equip(ItemLibrary items, AttributeSet stats, in ItemInstance item, ModifierSource slot) {        var modifiers = new List<Modifier>();        ItemStats.Compute(items, item, slot, modifiers);        foreach (var modifier in modifiers) {            stats.Add(modifier);        }    }    // Exact, because the kernel removes by source rather than by subtracting values back off.    public static void Unequip(AttributeSet stats, ModifierSource slot) => stats.RemoveBySource(slot);}

See also#

  • Inventory — what holds an item, and the only thing that may change one.
  • Loot — where instances come from, and where their seeds come from.
  • Attributes — what a stat block is made of.