Bevy data resources (docs-first stub)
Not a full port. Data is a Component or a Resource. There is no scene-file twin.
When to use
Load this when you are deciding where a piece of data lives: on many entities, or once for the whole app. The Resources page and the ECS page are the source for the names below.
ECS shape
- Components are for data you query across entities (
Component,Query). Use them when many things carry the same kind of fields. - Resources are globally unique data (
Resource). The Resources page names elapsed time, asset collections, and renderers as examples. Access them withRes<T>(read) andResMut<T>(write). - Insert.
insert_resourceplaces a resource on theApp. The page's sample derivesResourceonGreetTimer(Timer)and insertsTimer::from_seconds(2.0, TimerMode::Repeating). - Time.
Timeis inserted byadd_plugins(DefaultPlugins).time.delta()is the elapsed time since the last update.Timer::tickandjust_finishedare the page's timer methods. - Schedule: The sample reads
Res<Time>andResMut<GreetTimer>inside anUpdatesystem. Startup versus update is on the ECS page.
Asset loading APIs were not opened. "Asset collections" on the Resources page is an example of what a resource might hold, not a loader type.
Godot idea to Bevy idiom
| Idea | Bevy idiom (idea only) |
|---|---|
| Data on one gameplay thing | A Component |
| One copy for the whole app | A Resource inserted with insert_resource |
| Shared clock | Time from DefaultPlugins, or your own Resource |
| Authored data file | Not opened. Do not invent a file format or loader |
Gaps
- Asset handles, serialization, and reflection-based loading were not opened.
- Resource initialization order across plugins was not opened beyond a single
insert_resourcecall insidePlugin::build. - Per-entity data files and save blobs are out of scope. See the save-load matrix row when that skill exists.
Expert Knowledge Delta
Library target in prose: Bevy 0.20.0. Lattice URLs stay unversioned.
Opened canon only: Component, Resource, Query, Commands, Startup, Update, Fixed / FixedMain (bevy::time), .chain(), Plugin, DefaultPlugins, MinimalPlugins. Messages and observers are an ownership slot. This file does not invent their struct 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 this skill did not open | A Gaps row | A fabricated crate (solver, navmesh module, net, XR) |
Load references/a-gate-notes.md for the same table plus the gap rule.
NEVER
-
Do not put
/0.20.0/in lattice URLs. WHY: permalinks stay onlatest. The 0.20.0 pin belongs in prose once. -
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: those rows are gaps, blocked, or revisit.
-
No Godot resource, packed-scene, or data-file types. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar.
-
No invented asset or serialization APIs. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar.
-
No third-party crates. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar.
-
No Creation Station content. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar.
-
No umbrella skill over Godot and Bevy. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar.
-
Do not mark this row
ported. It isdocs_mapped. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar.
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.
- Resources -
Resource,Res,ResMut,insert_resource,Time,Timer,TimerMode. - Quick Start: ECS -
ComponentandQueryfor per-entity data. - Apps - Resources as the single copy of global data in the
World. - Examples - Example tree on the
latestbranch.
Related Skills
Prerequisites
- bevy-master - Component versus resource ownership.
- bevy-ecs-composition - How components are spawned and queried.
Complements
- bevy-app-resources - Schedules and plugins around those resources.
- godot-resource-data-patterns - Godot counterpart. Source idea only. Do not import Godot types.
Downstream / consumers
- None yet. Inventory, stats, and save skills are not ported.
Master
- bevy-master - Bevy router.


