bevy-physics-2d

Jak używać

Skopiuj polecenie instalacji i sprawdź źródła przed instalacją we własnym środowisku agenta.
W oryginale sprawdź wymagane narzędzia, dane dostępowe i obsługiwane środowiska.
Opisz dane wejściowe i oczekiwany rezultat; porównaj wynik ze źródłami.

npx skills add https://github.com/thedivergentai/game-design-agentic-skills --skill bevy-physics-2d

Przed rozpoczęciem

Instalacja nie obejmuje subskrypcji modelu, limitu API ani uprawnień do plików.
Gwiazdki i instalacje pokazują aktywność, a nie niezależny test jakości lub bezpieczeństwa.

Oryginalny dokument Skill

Treść z repozytorium z zachowaniem nagłówków, przykładów, kodu, tabel, linków i obrazów.

Bevy 2D physics

When to use

Load this when a Bevy app needs simulated 2D bodies, triggers, or layer filtering before choosing a solver. Pair with bevy-character-movement for player motion that should not be a rigid body. Pair with bevy-spatial-queries for casts that also wait on a solver.

ECS shape

Components would own body kind, velocity, and collider data once a solver crate is chosen. The ECS page only shows plain Component structs. It does not define a rigid body.
Resources would own gravity and solver settings. Check the solver docs before naming those fields.
Systems would step the solver on a fixed schedule. bevy::time documents Fixed and run_fixed_main_schedule (FixedMain). That is a clock, not a physics engine.
Schedule: fixed timestep for the step; .chain() when a system must see the step result before it runs (ECS page).

Coming from Godot

Godot idea	Bevy idiom
Simulated 2D prop	Entity plus solver-defined components, after a crate is verified
Player locomotion	Not a rigid body. Use bevy-character-movement
Trigger volumes	Choose a physics solver before adding trigger volumes.
Layers and masks	Unverified. Do not copy Godot bit names

Scope

The bevy 0.20.0 crate feature list on docs.rs has no physics-engine feature. 2D collision shapes, layers, and masks are not Bevy names on these pages.
Third-party plugins are allowed by the plugins page (add a crate, then add_plugins). Check a 2D physics crate's own docs before naming its plugin path.
Raycasts, CCD, and collision events need a chosen solver. Route query design to bevy-spatial-queries.

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`	A Godot node script
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 Godot 2D physics node or server types. WHY: Bevy code stays idiomatic ECS and uses only documented Bevy APIs.
No Avian, Rapier, or any other named physics crate as the chosen solver. WHY: Bevy code stays idiomatic ECS and uses only documented Bevy APIs.
No invented collider, layer, or joint APIs. WHY: Bevy code stays idiomatic ECS and uses only documented Bevy APIs.

Reference

docs.rs links use the unversioned latest permalink. The library pin on bevy-master stays 0.20.0.

Official Documentation

Migration guides - Unversioned hop index.
bevy crate - Unversioned API index. The 0.20.0 feature list has no physics-engine feature.
Assets - Official asset catalog. No physics plugin is named from it here.
Examples - Example tree on the latest branch.
Quick Start: plugins - Plugin, DefaultPlugins, MinimalPlugins, and third-party add_plugins.
ECS - Component, systems, Query, Startup, Update, and .chain().
bevy::time - Fixed and run_fixed_main_schedule (FixedMain) as a clock, not a solver.

Related Skills

Prerequisites

bevy-master - ECS ownership and the fixed-timestep schedule names.

Complements

bevy-physics-3d - Simulated 3D bodies and solver choice.
bevy-character-movement - Player locomotion that should not be a rigid body.
bevy-spatial-queries - Casts and overlaps. Choose a physics solver before adding them.
godot-2d-physics - Equivalent Godot skill.

Downstream / consumers

Combat and shooter skills cover hit detection and shots.

Master

bevy-master - Bevy router.