bevy_society

Living societies for Bevy: villagers who remember, gossip, take sides, fall out and make up. Big Five personalities, moods on a pleasure/arousal/dominance axis, an OCC emotion set, needs that decay and memories that fade; utility-AI daily lives over tagged places and other people; directed ties with a Dunbar-style cap; opinions, rumors, reputation and factions; Rhai scripts, dialogue through bevy_speech_bubbles; and a save that restores the society the reload would have produced.

cargo run --release --example capture -- --scene village: one afternoon in a village of twenty-four people. The plate reads Day 4 · 14:01 Friendships 30 · Rivalries 1 on the first frame and Day 4 · 20:01 Friendships 27 · Rivalries 1 with “Bram stole bread” — known by 2/24 on the last.

Add it

cargo add bevy_society

#![allow(unused)]
fn main() {
use bevy::prelude::*;
use bevy_society::{
    Autonomous, Home, Person, Place, PlaceTags, SocietyClock, SocietyDefs, SocietyPlugins,
    SocietySettings,
};

let defs = SocietyDefs::starter().expect("the starter pack is valid");
// A headless app has no frame clock, so `Time<Fixed>` never advances on its own. Without this the
// society takes zero ticks however many updates you run.
let step = std::time::Duration::from_secs_f64(1.0 / 64.0);

let mut app = App::new();
app.add_plugins((MinimalPlugins, TransformPlugin))
    .insert_resource(bevy::time::TimeUpdateStrategy::ManualDuration(step))
    .insert_resource(SocietySettings::default())
    .insert_resource(defs);
// `DialoguePlugin` needs a speech-bubbles plugin over a camera, which this snippet has not.
let plugins = SocietyPlugins.build();
#[cfg(feature = "dialogue")]
let plugins = plugins.disable::<bevy_society::DialoguePlugin>();
app.add_plugins(plugins);

let well = app
    .world_mut()
    .spawn((Name::new("well"), Place { capacity: 6 }, PlaceTags(vec!["gathering".into()]), Transform::default()))
    .id();
for name in ["Bram", "Alys", "Corin"] {
    app.world_mut()
        .spawn((Person, Autonomous, Name::new(name), Home(well), Transform::default()));
}

for _ in 0..600 {
    app.update();
}
// The society advanced: this line is what proves the fixed step was pinned.
assert!(app.world().resource::<SocietyClock>().tick > 0);
}

With the default dialogue feature, DialoguePlugin panics in finish without bevy_speech_bubbles::SpeechBubblesPlugin::<YourCamera> over a camera; add that first, or .disable::<DialoguePlugin>() as above.

What it gives you

• People with a mind. Big Five personalities, PAD mood, OCC emotions, decaying needs, fading memories, and a Chronotype so a lark and an owl keep their own hours in one village. features
• A day they choose. Utility-AI scoring over tagged places and other people, with travel, arrival, durations, per-tier ranks and an urgency that wins the tier while a need is low. features
• Relationships. Directed ties with affinity, trust, respect and familiarity, a Dunbar-style cap, friend and rival labels with hysteresis, and rebuff memory so someone turned down stops asking. features
• Opinions, rumors, reputation and factions. Bounded-confidence influence, Daley–Kendall gossip, witnesses who judge deeds and hold grudges, in-group affinity and conferred standing. features
• Scripts. Rhai triggers over a per-tick snapshot, bound to an area, a faction or named people, with a ctx reader and an fx writer that cannot see its own writes. scripting
• An economy and a save file. Goods as quantities with a per-head price, sharing and swapping between people, and capture/restore of the whole society. features · persistence
• An editor’s handles. fast_forward, preview_forward (run a day, report what moved, put it back), test_trigger, check_script, place_dependents and persons_in_rect. editor

Use it in the Cauldron

The Cauldron takes bevy_society as an optional cargo feature, named bevy_society in Cargo.toml and in a project’s family.ron. When the project lists it, the editor:

• writes the crate’s own settings through family_set, which rewrites one dot-pathed field of the RON file the crate’s serde types parse — the editor holds no schema for them, so it keeps the rest of the file as the author left it;
• refuses a definitions file the crate would reject: a saved society definition goes through bevy_society::SocietyDefs::from_ron first, so a file the loader would not compile is never written;
• authors people on a map through person_set (<emerge_dir>/people/<map>.ron), with a name, a position, a faction the project’s definitions declare, a home, a workplace and starting ties;
• runs a map’s people forward through people_run, which spawns them in bevy_society’s own headless app and reports where each went and which ties moved — the crate’s systems decide, the editor adds no behaviour.

A settings panel for this crate would edit SocietySettings (seed, tick_secs, seconds_per_day, start_hour, start_weekday, the clock source, locomotion, the society plane and the perception, contact and interaction radii), the tie capacities (max_ties, close_ties), the memory and knowledge capacities, and the rates on Tuning — every one of which is Serialize through the crate’s settings types. SocietyDefs itself is authored as a DefsFile in RON, and DefsFile::to_ron exists so an editor can save what it edited.

Links

• Repository
• docs.rs
• crates.io
• CHANGELOG