Loot containers

enshwick::loot reads the containers a dead enemy leaves, corpses and loot bags, and other containers that dissolve once emptied. It reads only; empty a container through Inventories. To put items into the loot a container rolls, see Random loot.

Each check of the containers

The game checks every such container each step in one ECS system, loot::SYSTEM (destroy_inventory_on_loot), on a worker thread. load.on_loot_pass runs a handler after each run of it in the server’s world, with a LootPass that walks that run’s containers and reads any entity as one:

use enshwick::world::near;

fn init(load: &mut enshwick::Load<'_>) -> Result<(), enshwick::Off> {
    load.on_loot_pass(|pass| {
        let spot = [0.0, 0.0, 0.0];
        let mut open = 0;
        pass.each(|c| {
            if c.is_open() && near(spot, c.position, 12.0, 4.0) {
                open += 1;
            }
        });
        let _ = open;
    })
}

each leaves the system’s row where it found it, so the walk does not disturb vanilla. Keep the handler short; it runs every step. A mod that walks another system with the same reads uses the unsafe Containers from that system’s own hook; see ECS inside systems.

Reading one container

Container holds what one container is and holds, read in one go:

Field	Meaning
entity	The container.
position	Where it stands, in metres; y is up.
is_empty	Whether it holds nothing, as the game last recorded.
expires	Whether it despawns on its own after a while (LifeTime).
area_loot	Its AreaLootOverride: Some(true) when area loot may take it, Some(false) when excluded (items a player dropped), None without one.
offer	Its interaction offer, an InteractionOfferRuntime; None without one.

An InteractionOfferRuntime names who last opened or looted the container (guest_id, None before anyone did), when (last_accept_time, in the game’s nanoseconds, changing with each interaction) and whether the game offers no interaction now (is_disabled).

Two methods sort containers:

• is_enemy_loot(): it expires and is open to area loot. That keeps corpses and enemy loot bags, and leaves out player chests, world chests, quest containers and items a player dropped;
• is_open(): enemy loot that also holds something and offers its interaction, so a player could take from it now.

Other entities

From inside any hooked system, with its context:

• container(ctx, entity) reads one entity as a loot container; None when it is not one (no DestroyOnLoot, inventory state or position) or is gone;
• position(ctx, entity) gives any entity’s position in metres;
• is_player(ctx, entity) tells whether an entity is a player character, such as an offer’s guest_id.

near(center, at, radius, height) tells whether at lies within radius metres of center across the ground and within height metres above or below it:

use enshwick::world::near;

assert!(near([0.0, 0.0, 0.0], [6.0, 3.0, 8.0], 10.0, 4.0));
assert!(!near([0.0, 0.0, 0.0], [6.0, 5.0, 8.0], 10.0, 4.0));

On a hosting client

A client that hosts a game runs the system in the built-in server’s world and in its own. on_loot_pass calls its handler for the server’s world only, checked with Worlds::is_server(ctx), so the handler needs no check of its own. Entity ids of the two worlds are unrelated. See Sides and hosting.

A server-side loot mod declares side: SERVER; the client loads SERVER mods too, for the games it hosts.

A worked example

A mod that empties the loot around a container a player just emptied into the same player puts the pieces of this chapter together. The steps follow one such mod’s take.rs:

1. At init it resolves Containers, Inventories and Worlds, and hooks loot::SYSTEM.
2. The hook calls vanilla first, then skips any context for which is_server is false, and walks the containers with each. It catches a panic in its own pass and turns itself off, so the game keeps running vanilla.
3. A tracker remembers each container’s state between steps. A container that went empty after a player’s interaction (the offer’s guest_id, checked with is_player) starts a take.
4. It gathers the containers around that are is_open() and near within the configured radius and height, and leaves out any that another player opened or looted in the last 10 seconds, or whose last guest, another player, still stands within 4 metres.
5. It empties them one at a time with a MoveAll batch, nearest first, and goes on to the next only when the batch committed and a read in the callback shows the last one empty. A full inventory stops it.
6. On ShutdownStarted it clears the tracker: entity ids belong to one game.