Bevy mobile platform

When to use

Load this when targeting touch devices. Check the platform docs for safe-area and store-listing steps before writing them. XR is a separate topic.

ECS shape

• Input features: touch (enabled by bevy_window) and gestures (enabled by bevy_window).
• Android: android-game-activity is the default Android activity. android-native-activity is marked legacy.
• Textures: compressed_image_saver mentions ASTC for mobile via an environment variable. Check that feature's docs for the variable's behavior beyond that blurb.
• Log: bevy::log says it configures platform log handlers including Android. Check that page for handler setup before writing it.

Coming from Godot

Godot idea	Bevy idiom
Touch	The touch feature. Check the input docs for button mapping before writing it. See bevy-input-handling for keyboard and mouse.
Android activity	android-game-activity feature.
Safe area	Unverified. No safe-area type was on the window page summary.

Scope

• The feature list names ScreenEdge on the window page, which documents a winit iOS screen-edge correspondence. Check that page for the rules before writing them.
• Check the platform docs for store packaging, permissions, and safe-area insets before writing them.

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 touch-screen or safe-margin project settings. WHY: Bevy code stays idiomatic ECS and uses only documented Bevy APIs.

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

• No invented APIs or unnamed third-party crates as the chosen solver. 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 - API reference and Cargo feature list.
• 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.
• bevy::window - ScreenEdge mentions winit iOS. Check that page before treating touch events as their own struct.

Related Skills

Prerequisites

• bevy-master - Hub and schedules.
• bevy-ecs-composition - Components and systems.
• bevy-input-handling - Other devices.
• bevy-platform-desktop - Window shell.

Complements

• bevy-adapt-desktop-to-mobile - Layout and input adapt.
• godot-platform-mobile - Equivalent Godot skill.

Downstream / consumers

• None yet.

Master

• bevy-master - Bevy router.