Bevy Romance

Genre router. Domain work lives in the Bevy skills below.

When to use

Load this for relationship values and scene routes on top of dialogue.

ECS shape

• Components hold the genre's per-entity flags as plain data. This file does not name new engine types.
• Resources hold run-wide counters (score, wave index, seed) via bevy-data-resources.
• Systems read those components on Update or the fixed timestep from bevy-master. Order them with .chain() when a later system must see the result.
• Schedule: gameplay mode changes go through bevy-state-machines. Affection and route flags below are a component plus one resource.

Examples

[dependencies]
bevy = "0.20"

Each character stores affection and the last choice. Route flags are a resource. Apply the choice, then pick the next scene id. Those systems share Bond, so they chain.

#[derive(Clone, Copy, PartialEq, Eq)]
enum Choice {
    Warm,
    Cool,
}

#[derive(Component)]
struct Bond {
    affection: i32,
    last: Choice,
}

#[derive(Resource)]
struct RouteFlags {
    confession_open: bool,
    scene: u32,
}

fn boot(mut commands: Commands) {
    commands.insert_resource(RouteFlags {
        confession_open: false,
        scene: 0,
    });
    commands.spawn(Bond {
        affection: 0,
        last: Choice::Cool,
    });
}

fn apply_choice(keys: Res<ButtonInput<KeyCode>>, mut bonds: Query<&mut Bond>) {
    let choice = if keys.just_pressed(KeyCode::Digit1) {
        Some(Choice::Warm)
    } else if keys.just_pressed(KeyCode::Digit2) {
        Some(Choice::Cool)
    } else {
        None
    };
    let Some(choice) = choice else {
        return;
    };
    for mut bond in &mut bonds {
        bond.last = choice;
        bond.affection += if choice == Choice::Warm { 10 } else { -5 };
    }
}

fn advance_route(bonds: Query<&Bond>, mut route: ResMut<RouteFlags>) {
    let Some(bond) = bonds.iter().next() else {
        return;
    };
    route.confession_open = bond.affection >= 30;
    if route.confession_open {
        route.scene = 4;
    } else if bond.last == Choice::Warm {
        route.scene = 2;
    } else {
        route.scene = 1;
    }
}

fn install(app: &mut App) {
    app.add_systems(Startup, boot)
        .add_systems(Update, (apply_choice, advance_route).chain());
}

A scene is available when affection is at least the threshold stored on that scene.

#[derive(Component)]
struct SceneGate {
    id: u32,
    min_affection: i32,
}

#[derive(Component)]
struct Bond {
    affection: i32,
}

fn gate_open(bonds: Query<&Bond>, gates: Query<&SceneGate>, scene_id: u32) -> bool {
    let Some(bond) = bonds.iter().next() else {
        return false;
    };
    gates
        .iter()
        .any(|gate| gate.id == scene_id && bond.affection >= gate.min_affection)
}

Scene shape

Piece	Bevy idiom
Genre content	Entities plus the domain skills linked below
Run-wide director	A Resource
Loop notices	bevy-events-messaging

Routing

• bevy-dialogue-system - Scenes.
• bevy-rpg-stats - Affection as a stat you name.
• bevy-save-load - Route flags.

Scope

• Affection lives on Bond. RouteFlags stores the open scene. Bevy has no relationship type; the example above is the data.

Expert Knowledge Delta

Target: Bevy 0.20+.

Core ECS types: Component, Resource, Query, Commands, Startup, Update, Fixed / FixedMain (bevy::time), .chain(), Plugin, DefaultPlugins, MinimalPlugins. Messages and observers are an ownership slot. See bevy-events-messaging for their APIs. Systems run in parallel unless .chain() orders the ones that conflict.

Who owns state

Piece	Owner	Who may mutate	Schedule
Data on one entity	Component	One system via Query	Update or FixedMain
One value for the whole app	Resource	One system	Startup to insert, then the schedule that reads it
Spawn	Commands	The spawning system	Startup for the initial world; later schedules for runtime spawn
Order that must not race	.chain()	The chained systems only	Same schedule
Plugin boundary	Plugin	build registers systems and resources	Before the app runs

Borrow rule: two systems that both mutably query the same component must be ordered (.chain()) or split so only one writes. Unrelated systems stay parallel. That is the ECS page rule, not a guess at a system-set API.

Decision

If you need	Do this	Do not
Per-entity data	Component + Query	One script that owns the whole tree
App-wide config or clock	Resource	Copy the value onto every entity
Stable simulation step	FixedMain and the Fixed clock	Tie simulation to raw frame Update
Startup spawn	Commands in Startup	Spawn from a render system
Cross-system notice that is not shared state	Message or observer slot in bevy-events-messaging	A new event type invented in this file
An API outside the documented set	Check the official docs first	A made-up crate or API

Load references/ecs-ownership.md for the ownership table.

NEVER

• Do not pin /0.20.0/ in docs URLs. WHY: links stay on latest; the 0.20 target is stated once in prose.

• Do not mutably query the same component from two unordered systems. WHY: the schedule runs systems in parallel unless .chain() orders them.

• Do not invent a physics, navigation, networking, or XR crate here. WHY: this skill only names documented Bevy crates and modules.

• No foreign-engine types in Bevy code. WHY: Bevy code stays idiomatic ECS and uses only documented Bevy APIs.

• No invented genre APIs. WHY: Bevy code stays idiomatic ECS and uses only documented Bevy APIs.

• Do not pick a physics or net crate here. WHY: Bevy code stays idiomatic ECS and uses only documented Bevy APIs.

Reference

Official pages stay on unversioned permalinks. The library pin on bevy-master stays 0.20.

Official Documentation

• Assets - Official asset catalog. No third-party crate was selected.
• Examples - Example tree on the latest branch.
• ECS - Component, systems, Query, Startup, Update, and .chain().
• Plugins - Plugin, DefaultPlugins, MinimalPlugins, and add_plugins.

Related Skills

Prerequisites

• bevy-master - ECS ownership and schedules.
• bevy-ecs-composition - Spawn and query shape.

Complements

• godot-genre-romance - Peer skill for the same genre.
• bevy-dialogue-system - Scenes.
• bevy-rpg-stats - Affection as a stat you name.
• bevy-save-load - Route flags.

Downstream / consumers

• None. This router does not own a second implementation.

Master

• bevy-master - Bevy router.