Commit graph

185 commits

Author SHA1 Message Date
SpecificProtagonist
86aaad743b
Merge ScheduleRunnerSettings into ScheduleRunnerPlugin (#8585)
# Objective

`ScheduleRunnerPlugin` was still configured via a resource, meaning
users would be able to change the settings while the app is running, but
the changes wouldn't have an effect.

## Solution

Configure plugin directly

---

## Changelog

- Changed: merged `ScheduleRunnerSettings` into `ScheduleRunnerPlugin` 

## Migration Guide

- instead of inserting the `ScheduleRunnerSettings` resource, configure
the `ScheduleRunnerPlugin`
2023-05-10 16:46:21 +00:00
Wybe Westra
abf12f3b3b
Fixed several missing links in docs. (#8117)
Links in the api docs are nice. I noticed that there were several places
where structs / functions and other things were referenced in the docs,
but weren't linked. I added the links where possible / logical.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: François <mockersf@gmail.com>
2023-04-23 17:28:36 +00:00
François
e0e5f3acd4
add a default font (#8445)
# Objective

- Have a default font

## Solution

- Add a font based on FiraMono containing only ASCII characters and use
it as the default font
- It is behind a feature `default_font` enabled by default
- I also updated examples to use it, but not UI examples to still show
how to use a custom font

---

## Changelog

* If you display text without using the default handle provided by
`TextStyle`, the text will be displayed
2023-04-21 22:30:18 +00:00
François
347dc0982c
typo on schedule StateTransitions name in example (#8443)
# Objective

- Fix a typo

## Solution

- Fix the typo
2023-04-20 11:33:45 +00:00
张林伟
5c7abb0579
Remove OnUpdate system set (#8260)
# Objective

- Fixes https://github.com/bevyengine/bevy/issues/8239.

## Solution

- Replace `OnUpdate` with `run_if(in_state(xxx))`.

---

## Migration Guide

- Replace `OnUpdate` with `run_if(in_state(xxx))`.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2023-04-04 00:49:41 +00:00
Natalia
7a9e77c79c
make the examples use the States derive macro (#8289)
# Objective
Some examples still manually implement the States trait, even though
manual implementation is no longer needed as there is now the derive
macro for that.

---------

Signed-off-by: Natalia Asteria <fortressnordlys@outlook.com>
2023-04-02 04:25:47 +00:00
Carter Anderson
aefe1f0739
Schedule-First: the new and improved add_systems (#8079)
Co-authored-by: Mike <mike.hsu@gmail.com>
2023-03-18 01:45:34 +00:00
JoJoJet
fd1af7c8b8
Replace multiple calls to add_system with add_systems (#8001) 2023-03-10 18:15:22 +00:00
shuo
002c9d8b7f fix whitespaces in comment (#7853)
fix double whitespaces in comments. (I know it's dumb commit, while reading code, double spaces hurts a little... :P)
2023-03-01 10:20:56 +00:00
Anselmo Sampietro
998e983bac Add example to show how to use apply_system_buffers (#7793)
# Objective

This PR adds an example that shows how to use `apply_system_buffers` and how to order it with respect to the relevant systems. It also shows how not ordering the systems can lead to unexpected behaviours.

## Solution

Add the example.
2023-02-28 00:19:44 +00:00
JoJoJet
b8263b55fb Support system.in_schedule() and system.on_startup() (#7790)
# Objective

Support the following syntax for adding systems:

```rust
App::new()
    .add_system(setup.on_startup())
    .add_systems((
        show_menu.in_schedule(OnEnter(GameState::Paused)),
        menu_ssytem.in_set(OnUpdate(GameState::Paused)),
        hide_menu.in_schedule(OnExit(GameState::Paused)),
    ))
```

## Solution

Add the traits `IntoSystemAppConfig{s}`, which provide the extension methods necessary for configuring which schedule a system belongs to. These extension methods return `IntoSystemAppConfig{s}`, which `App::add_system{s}` uses to choose which schedule to add systems to.

---

## Changelog

+ Added the extension methods `in_schedule(label)` and  `on_startup()` for configuring the schedule a system belongs to.

## Future Work

* Replace all uses of `add_startup_system` in the engine.
* Deprecate this method
2023-02-24 18:33:55 +00:00
Rob Parrett
03c545056c Fix some more typos (#7767)
# Objective

I managed to dig up some more typos with a combination of the "[code spell checker](https://marketplace.visualstudio.com/items?itemName=streetsidesoftware.code-spell-checker)" and "[open folder](https://marketplace.visualstudio.com/items?itemName=rwu823.open-folder)" vscode extensions.

## Solution

Fix em
2023-02-20 23:36:28 +00:00
JoJoJet
0c98f9a225 Add AND/OR combinators for run conditions (#7605)
# Objective

Fix #7584.

## Solution

Add an abstraction for creating custom system combinators with minimal boilerplate. Use this to implement AND/OR combinators. Use this to simplify the implementation of `PipeSystem`.

## Example

Feel free to bikeshed on the syntax.

I chose the names `and_then`/`or_else` to emphasize the fact that these short-circuit, while I chose method syntax to empasize that the arguments are *not* treated equally.

```rust
app.add_systems((
    my_system.run_if(resource_exists::<R>().and_then(resource_equals(R(0)))),
    our_system.run_if(resource_exists::<R>().or_else(resource_exists::<S>())),
));
```

---

## Todo

- [ ] Decide on a syntax
- [x] Write docs
- [x] Write tests

## Changelog

+ Added the extension methods `.and_then(...)` and `.or_else(...)` to run conditions, which allows combining run conditions with short-circuiting behavior.
+ Added the trait `Combine`, which can be used with the new `CombinatorSystem` to create system combinators with custom behavior.
2023-02-20 18:16:11 +00:00
JoJoJet
5a5125671b Deprecate ChangeTrackers<T> in favor of Ref<T> (#7306)
# Objective

`ChangeTrackers<>` is a `WorldQuery` type that lets you access the change ticks for a component. #7097 has added `Ref<>`, which gives access to a component's value in addition to its change ticks. Since bevy's access model does not separate a component's value from its change ticks, there is no benefit to using `ChangeTrackers<T>` over `Ref<T>`.

## Solution

Deprecate `ChangeTrackers<>`.

---

## Changelog

* `ChangeTrackers<T>` has been deprecated. It will be removed in Bevy 0.11.

## Migration Guide

`ChangeTrackers<T>` has been deprecated, and will be removed in the next release. Any usage should be replaced with `Ref<T>`.

```rust
// Before (0.9)
fn my_system(q: Query<(&MyComponent, ChangeTrackers<MyComponent>)>) {
    for (value, trackers) in &q {
        if trackers.is_changed() {
            // Do something with `value`.
        }
    }
}

// After (0.10)
fn my_system(q: Query<Ref<MyComponent>>) {
    for value in &q {
        if value.is_changed() {
            // Do something with `value`.
        }
    }
}
```
2023-02-19 16:19:56 +00:00
Liam Gallagher
50bba0f595 Add example for run conditions (#7652)
Added an example for run conditions. Fixes #7646 if we wait till #7605 is merged and include some of it features.
2023-02-18 05:32:59 +00:00
James Liu
04256735f6 Cleanup ScheduleBuildSettings (#7721)
# Objective
Fix #7440. Fix #7441. 

## Solution

 * Remove builder functions on `ScheduleBuildSettings` in favor of public fields, move docs to the fields.
 * Add `use_shortnames` and use it in `get_node_name` to feed it through `bevy_utils::get_short_name`.
2023-02-17 15:17:52 +00:00
ZoOL
2efc0293ed Remove Anyhow::Result in system_piping.rs example (#7657)
# Objective

Fixes: #7610 

## Solution

- Return a specific error type
2023-02-14 03:33:47 +00:00
tomaspecl
9dadde06cb Fixed a typo in an example state.rs (#7666)
# Objective

Found and fixed a typo in an example ecs/state.rs
2023-02-14 01:16:33 +00:00
Alice Cecile
0a9c469d19 Remove .on_update method to improve API consistency and clarity (#7667)
# Objective

Fixes #7632.

As discussed in #7634, it can be quite challenging for users to intuit the mental model of how states now work.

## Solution

Rather than change the behavior of the `OnUpdate` system set, instead work on making sure it's easy to understand what's going on.

Two things have been done:

1. Remove the `.on_update` method from our bevy of system building traits. This was special-cased and made states feel much more magical than they need to.
2. Improve the docs for the `OnUpdate` system set.
2023-02-14 00:13:10 +00:00
Rob Parrett
1b444975ed Fix panics in ecs_guide example (#7525)
# Objective

Fixes #7565

`ecs_guide` example is currently panicking. This seems to just be a problem with the example only caused by the base sets PR.

## Solution

First, changed a few `in_set` to `in_base_set` to fix a few of

```
thread 'main' panicked at 'Systems cannot be added to 'base' system sets using 'in_set'. Use 'in_base_set' instead.', examples/ecs/ecs_guide.rs:301:45
```

And then added an `in_base_set` to fix the resulting (confusing) cycle error

```
2023-02-06T13:54:29.213843Z ERROR bevy_ecs::schedule_v3::schedule: schedule contains at least 1 cycle(s) -- cycle(s) found within:
 ---- 0: ["ecs_guide::game_over_system", "ecs_guide::score_check_system"]
```

I also changed this `add_system` call so the comment above and below make sense:
```diff
         // add_system(system) adds systems to the Update system set by default
         // However we can manually specify the set if we want to. The following is equivalent to
         // add_system(score_system)
-        .add_system(score_system)
+        .add_system(score_system.in_base_set(CoreSet::Update))
         // There are other `CoreSets`, such as `Last` which runs at the very end of each run.
```

## Notes

- Does `MySet` even need to be a base set? Seems like yes.
- Is that cycle error when there is no explicit `in_base_set` actually expected?
2023-02-08 23:01:53 +00:00
SpecificProtagonist
6314f50e7b States derive macro (#7535)
# Objective
Implementing `States` manually is repetitive, so let's not.

One thing I'm unsure of is whether the macro import statement is in the right place.
2023-02-07 14:02:21 +00:00
张林伟
aa4170d9a4 Rename schedule v3 to schedule (#7519)
# Objective

- Follow up of https://github.com/bevyengine/bevy/pull/7267

## Solution

- Rename schedule_v3 to schedule
- Suppress "module inception" lint
2023-02-06 18:44:40 +00:00
Carter Anderson
dcc03724a5 Base Sets (#7466)
# Objective

NOTE: This depends on #7267 and should not be merged until #7267 is merged. If you are reviewing this before that is merged, I highly recommend viewing the Base Sets commit instead of trying to find my changes amongst those from #7267.

"Default sets" as described by the [Stageless RFC](https://github.com/bevyengine/rfcs/pull/45) have some [unfortunate consequences](https://github.com/bevyengine/bevy/discussions/7365).

## Solution

This adds "base sets" as a variant of `SystemSet`:

A set is a "base set" if `SystemSet::is_base` returns `true`. Typically this will be opted-in to using the `SystemSet` derive:

```rust
#[derive(SystemSet, Clone, Hash, Debug, PartialEq, Eq)]
#[system_set(base)]
enum MyBaseSet {
  A,
  B,
}
``` 

**Base sets are exclusive**: a system can belong to at most one "base set". Adding a system to more than one will result in an error. When possible we fail immediately during system-config-time with a nice file + line number. For the more nested graph-ey cases, this will fail at the final schedule build. 

**Base sets cannot belong to other sets**: this is where the word "base" comes from

Systems and Sets can only be added to base sets using `in_base_set`. Calling `in_set` with a base set will fail. As will calling `in_base_set` with a normal set.

```rust
app.add_system(foo.in_base_set(MyBaseSet::A))
       // X must be a normal set ... base sets cannot be added to base sets
       .configure_set(X.in_base_set(MyBaseSet::A))
```

Base sets can still be configured like normal sets:

```rust
app.add_system(MyBaseSet::B.after(MyBaseSet::Ap))
``` 

The primary use case for base sets is enabling a "default base set":

```rust
schedule.set_default_base_set(CoreSet::Update)
  // this will belong to CoreSet::Update by default
  .add_system(foo)
  // this will override the default base set with PostUpdate
  .add_system(bar.in_base_set(CoreSet::PostUpdate))
```

This allows us to build apis that work by default in the standard Bevy style. This is a rough analog to the "default stage" model, but it use the new "stageless sets" model instead, with all of the ordering flexibility (including exclusive systems) that it provides.

---

## Changelog

- Added "base sets" and ported CoreSet to use them.

## Migration Guide

TODO
2023-02-06 03:10:08 +00:00
Alice Cecile
206c7ce219 Migrate engine to Schedule v3 (#7267)
Huge thanks to @maniwani, @devil-ira, @hymm, @cart, @superdump and @jakobhellermann for the help with this PR.

# Objective

- Followup #6587.
- Minimal integration for the Stageless Scheduling RFC: https://github.com/bevyengine/rfcs/pull/45

## Solution

- [x]  Remove old scheduling module
- [x] Migrate new methods to no longer use extension methods
- [x] Fix compiler errors
- [x] Fix benchmarks
- [x] Fix examples
- [x] Fix docs
- [x] Fix tests

## Changelog

### Added

- a large number of methods on `App` to work with schedules ergonomically
- the `CoreSchedule` enum
- `App::add_extract_system` via the `RenderingAppExtension` trait extension method
- the private `prepare_view_uniforms` system now has a public system set for scheduling purposes, called `ViewSet::PrepareUniforms`

### Removed

- stages, and all code that mentions stages
- states have been dramatically simplified, and no longer use a stack
- `RunCriteriaLabel`
- `AsSystemLabel` trait
- `on_hierarchy_reports_enabled` run criteria (now just uses an ad hoc resource checking run condition)
- systems in `RenderSet/Stage::Extract` no longer warn when they do not read data from the main world
- `RunCriteriaLabel`
- `transform_propagate_system_set`: this was a nonstandard pattern that didn't actually provide enough control. The systems are already `pub`: the docs have been updated to ensure that the third-party usage is clear.

### Changed

- `System::default_labels` is now `System::default_system_sets`.
- `App::add_default_labels` is now `App::add_default_sets`
- `CoreStage` and `StartupStage` enums are now `CoreSet` and `StartupSet`
- `App::add_system_set` was renamed to `App::add_systems`
- The `StartupSchedule` label is now defined as part of the `CoreSchedules` enum
-  `.label(SystemLabel)` is now referred to as `.in_set(SystemSet)`
- `SystemLabel` trait was replaced by `SystemSet`
- `SystemTypeIdLabel<T>` was replaced by `SystemSetType<T>`
- The `ReportHierarchyIssue` resource now has a public constructor (`new`), and implements `PartialEq`
- Fixed time steps now use a schedule (`CoreSchedule::FixedTimeStep`) rather than a run criteria.
- Adding rendering extraction systems now panics rather than silently failing if no subapp with the `RenderApp` label is found.
- the `calculate_bounds` system, with the `CalculateBounds` label, is now in `CoreSet::Update`, rather than in `CoreSet::PostUpdate` before commands are applied. 
- `SceneSpawnerSystem` now runs under `CoreSet::Update`, rather than `CoreStage::PreUpdate.at_end()`.
- `bevy_pbr::add_clusters` is no longer an exclusive system
- the top level `bevy_ecs::schedule` module was replaced with `bevy_ecs::scheduling`
- `tick_global_task_pools_on_main_thread` is no longer run as an exclusive system. Instead, it has been replaced by `tick_global_task_pools`, which uses a `NonSend` resource to force running on the main thread.

## Migration Guide

- Calls to `.label(MyLabel)` should be replaced with `.in_set(MySet)`
- Stages have been removed. Replace these with system sets, and then add command flushes using the `apply_system_buffers` exclusive system where needed.
- The `CoreStage`, `StartupStage, `RenderStage` and `AssetStage`  enums have been replaced with `CoreSet`, `StartupSet, `RenderSet` and `AssetSet`. The same scheduling guarantees have been preserved.
  - Systems are no longer added to `CoreSet::Update` by default. Add systems manually if this behavior is needed, although you should consider adding your game logic systems to `CoreSchedule::FixedTimestep` instead for more reliable framerate-independent behavior.
  - Similarly, startup systems are no longer part of `StartupSet::Startup` by default. In most cases, this won't matter to you.
  - For example, `add_system_to_stage(CoreStage::PostUpdate, my_system)` should be replaced with 
  - `add_system(my_system.in_set(CoreSet::PostUpdate)`
- When testing systems or otherwise running them in a headless fashion, simply construct and run a schedule using `Schedule::new()` and `World::run_schedule` rather than constructing stages
- Run criteria have been renamed to run conditions. These can now be combined with each other and with states.
- Looping run criteria and state stacks have been removed. Use an exclusive system that runs a schedule if you need this level of control over system control flow.
- For app-level control flow over which schedules get run when (such as for rollback networking), create your own schedule and insert it under the `CoreSchedule::Outer` label.
- Fixed timesteps are now evaluated in a schedule, rather than controlled via run criteria. The `run_fixed_timestep` system runs this schedule between `CoreSet::First` and `CoreSet::PreUpdate` by default.
- Command flush points introduced by `AssetStage` have been removed. If you were relying on these, add them back manually.
- Adding extract systems is now typically done directly on the main app. Make sure the `RenderingAppExtension` trait is in scope, then call `app.add_extract_system(my_system)`.
- the `calculate_bounds` system, with the `CalculateBounds` label, is now in `CoreSet::Update`, rather than in `CoreSet::PostUpdate` before commands are applied. You may need to order your movement systems to occur before this system in order to avoid system order ambiguities in culling behavior.
- the `RenderLabel` `AppLabel` was renamed to `RenderApp` for clarity
- `App::add_state` now takes 0 arguments: the starting state is set based on the `Default` impl.
- Instead of creating `SystemSet` containers for systems that run in stages, simply use `.on_enter::<State::Variant>()` or its `on_exit` or `on_update` siblings.
- `SystemLabel` derives should be replaced with `SystemSet`. You will also need to add the `Debug`, `PartialEq`, `Eq`, and `Hash` traits to satisfy the new trait bounds.
- `with_run_criteria` has been renamed to `run_if`. Run criteria have been renamed to run conditions for clarity, and should now simply return a bool.
- States have been dramatically simplified: there is no longer a "state stack". To queue a transition to the next state, call `NextState::set`

## TODO

- [x] remove dead methods on App and World
- [x] add `App::add_system_to_schedule` and `App::add_systems_to_schedule`
- [x] avoid adding the default system set at inappropriate times
- [x] remove any accidental cycles in the default plugins schedule
- [x] migrate benchmarks
- [x] expose explicit labels for the built-in command flush points
- [x] migrate engine code
- [x] remove all mentions of stages from the docs
- [x] verify docs for States
- [x] fix uses of exclusive systems that use .end / .at_start / .before_commands
- [x] migrate RenderStage and AssetStage
- [x] migrate examples
- [x] ensure that transform propagation is exported in a sufficiently public way (the systems are already pub)
- [x] ensure that on_enter schedules are run at least once before the main app
- [x] re-enable opt-in to execution order ambiguities
- [x] revert change to `update_bounds` to ensure it runs in `PostUpdate`
- [x] test all examples
  - [x] unbreak directional lights
  - [x] unbreak shadows (see 3d_scene, 3d_shape, lighting, transparaency_3d examples)
  - [x] game menu example shows loading screen and menu simultaneously
  - [x] display settings menu is a blank screen
  - [x] `without_winit` example panics
- [x] ensure all tests pass
  - [x] SubApp doc test fails
  - [x] runs_spawn_local tasks fails
  - [x] [Fix panic_when_hierachy_cycle test hanging](https://github.com/alice-i-cecile/bevy/pull/120)

## Points of Difficulty and Controversy

**Reviewers, please give feedback on these and look closely**

1.  Default sets, from the RFC, have been removed. These added a tremendous amount of implicit complexity and result in hard to debug scheduling errors. They're going to be tackled in the form of "base sets" by @cart in a followup.
2. The outer schedule controls which schedule is run when `App::update` is called.
3. I implemented `Label for `Box<dyn Label>` for our label types. This enables us to store schedule labels in concrete form, and then later run them. I ran into the same set of problems when working with one-shot systems. We've previously investigated this pattern in depth, and it does not appear to lead to extra indirection with nested boxes.
4. `SubApp::update` simply runs the default schedule once. This sucks, but this whole API is incomplete and this was the minimal changeset.
5. `time_system` and `tick_global_task_pools_on_main_thread` no longer use exclusive systems to attempt to force scheduling order
6. Implemetnation strategy for fixed timesteps
7. `AssetStage` was migrated to `AssetSet` without reintroducing command flush points. These did not appear to be used, and it's nice to remove these bottlenecks.
8. Migration of `bevy_render/lib.rs` and pipelined rendering. The logic here is unusually tricky, as we have complex scheduling requirements.

## Future Work (ideally before 0.10)

- Rename schedule_v3 module to schedule or scheduling
- Add a derive macro to states, and likely a `EnumIter` trait of some form
- Figure out what exactly to do with the "systems added should basically work by default" problem
- Improve ergonomics for working with fixed timesteps and states
- Polish FixedTime API to match Time
- Rebase and merge #7415
- Resolve all internal ambiguities (blocked on better tools, especially #7442)
- Add "base sets" to replace the removed default sets.
2023-02-06 02:04:50 +00:00
Aceeri
67826b21d4 Replace RemovedComponents<T> backing with Events<Entity> (#5680)
# Objective
Removal events are unwieldy and require some knowledge of when to put systems that need to catch events for them, it is very easy to end up missing one and end up with memory leak-ish issues where you don't clean up after yourself.

## Solution
Consolidate removals with the benefits of `Events<...>` (such as double buffering and per system ticks for reading the events) and reduce the special casing of it, ideally I was hoping to move the removals to a `Resource` in the world, but that seems a bit more rough to implement/maintain because of double mutable borrowing issues.

This doesn't go the full length of change detection esque removal detection a la https://github.com/bevyengine/rfcs/pull/44.
Just tries to make the current workflow a bit more user friendly so detecting removals isn't such a scheduling nightmare.

---

## Changelog
- RemovedComponents<T> is now backed by an `Events<Entity>` for the benefits of double buffering.

## Migration Guide
- Add a `mut` for `removed: RemovedComponents<T>` since we are now modifying an event reader internally.
- Iterating over removed components now requires `&mut removed_components` or `removed_components.iter()` instead of `&removed_components`.
2023-02-04 20:53:37 +00:00
Alice Cecile
5d514fb24f Reduce internal system order ambiguities, and add an example explaining them (#7383)
# Objective

- Bevy should not have any "internal" execution order ambiguities. These clutter the output of user-facing error reporting, and can result in nasty, nondetermistic, very difficult to solve bugs.
- Verifying this currently involves repeated non-trivial manual work. 

## Solution

- [x] add an example to quickly check this
- ~~[ ] ensure that this example panics if there are any unresolved ambiguities~~
- ~~[ ] run the example in CI 😈~~

There's one tricky ambiguity left, between UI and animation. I don't have the tools to fix this without system set configuration, so the remaining work is going to be left to #7267 or another PR after that.

```
2023-01-27T18:38:42.989405Z  INFO bevy_ecs::schedule::ambiguity_detection: Execution order ambiguities detected, you might want to add an explicit dependency relation between some of these systems:
 * Parallel systems:
 -- "bevy_animation::animation_player" and "bevy_ui::flex::flex_node_system"
    conflicts: ["bevy_transform::components::transform::Transform"]
  ```

## Changelog

Resolved internal execution order ambiguities for:
1. Transform propagation (ignored, we need smarter filter checking).
2. Gamepad processing (fixed).
3. bevy_winit's window handling (fixed).
4. Cascaded shadow maps and perspectives (fixed).

Also fixed a desynchronized state bug that could occur when the `Window` component is removed and then added to the same entity in a single frame.
2023-01-31 01:47:00 +00:00
Chris Ohk
3281aea5c2 Fix minor typos in code and docs (#7378)
# Objective

I found several words in code and docs are incorrect. This should be fixed.

## Solution

- Fix several minor typos

Co-authored-by: Chris Ohk <utilforever@gmail.com>
2023-01-27 12:12:53 +00:00
James Liu
dfea88c64d Basic adaptive batching for parallel query iteration (#4777)
# Objective
Fixes #3184. Fixes #6640. Fixes #4798. Using `Query::par_for_each(_mut)` currently requires a `batch_size` parameter, which affects how it chunks up large archetypes and tables into smaller chunks to run in parallel. Tuning this value is difficult, as the performance characteristics entirely depends on the state of the `World` it's being run on. Typically, users will just use a flat constant and just tune it by hand until it performs well in some benchmarks. However, this is both error prone and risks overfitting the tuning on that benchmark.

This PR proposes a naive automatic batch-size computation based on the current state of the `World`.

## Background
`Query::par_for_each(_mut)` schedules a new Task for every archetype or table that it matches. Archetypes/tables larger than the batch size are chunked into smaller tasks. Assuming every entity matched by the query has an identical workload, this makes the worst case scenario involve using a batch size equal to the size of the largest matched archetype or table. Conversely, a batch size of `max {archetype, table} size / thread count * COUNT_PER_THREAD` is likely the sweetspot where the overhead of scheduling tasks is minimized, at least not without grouping small archetypes/tables together.

There is also likely a strict minimum batch size below which the overhead of scheduling these tasks is heavier than running the entire thing single-threaded.

## Solution

- [x] Remove the `batch_size` from `Query(State)::par_for_each`  and friends.
- [x] Add a check to compute `batch_size = max {archeytpe/table} size / thread count  * COUNT_PER_THREAD`
- [x] ~~Panic if thread count is 0.~~ Defer to `for_each` if the thread count is 1 or less.
- [x] Early return if there is no matched table/archetype. 
- [x] Add override option for users have queries that strongly violate the initial assumption that all iterated entities have an equal workload.

---

## Changelog
Changed: `Query::par_for_each(_mut)` has been changed to `Query::par_iter(_mut)` and will now automatically try to produce a batch size for callers based on the current `World` state.

## Migration Guide
The `batch_size` parameter for `Query(State)::par_for_each(_mut)` has been removed. These calls will automatically compute a batch size for you. Remove these parameters from all calls to these functions.

Before:
```rust
fn parallel_system(query: Query<&MyComponent>) {
   query.par_for_each(32, |comp| {
        ...
   });
}
```

After:

```rust
fn parallel_system(query: Query<&MyComponent>) {
   query.par_iter().for_each(|comp| {
        ...
   });
}
```

Co-authored-by: Arnav Choubey <56453634+x-52@users.noreply.github.com>
Co-authored-by: Robert Swain <robert.swain@gmail.com>
Co-authored-by: François <mockersf@gmail.com>
Co-authored-by: Corey Farwell <coreyf@rwell.org>
Co-authored-by: Aevyrie <aevyrie@gmail.com>
2023-01-20 08:47:20 +00:00
Aceeri
ddfafab971 Windows as Entities (#5589)
# Objective

Fix https://github.com/bevyengine/bevy/issues/4530

- Make it easier to open/close/modify windows by setting them up as `Entity`s with a `Window` component.
- Make multiple windows very simple to set up. (just add a `Window` component to an entity and it should open)

## Solution

- Move all properties of window descriptor to ~components~ a component.
- Replace `WindowId` with `Entity`.
- ~Use change detection for components to update backend rather than events/commands. (The `CursorMoved`/`WindowResized`/... events are kept for user convenience.~
  Check each field individually to see what we need to update, events are still kept for user convenience.

---

## Changelog

- `WindowDescriptor` renamed to `Window`.
    - Width/height consolidated into a `WindowResolution` component.
    - Requesting maximization/minimization is done on the [`Window::state`] field.
- `WindowId` is now `Entity`.

## Migration Guide

- Replace `WindowDescriptor` with `Window`.
    - Change `width` and `height` fields in a `WindowResolution`, either by doing
      ```rust
      WindowResolution::new(width, height) // Explicitly
      // or using From<_> for tuples for convenience
      (1920., 1080.).into()
      ```
- Replace any `WindowCommand` code to just modify the `Window`'s fields directly  and creating/closing windows is now by spawning/despawning an entity with a `Window` component like so:
  ```rust
  let window = commands.spawn(Window { ... }).id(); // open window
  commands.entity(window).despawn(); // close window
  ```

## Unresolved
- ~How do we tell when a window is minimized by a user?~
  ~Currently using the `Resize(0, 0)` as an indicator of minimization.~
  No longer attempting to tell given how finnicky this was across platforms, now the user can only request that a window be maximized/minimized.
  
 ## Future work
 - Move `exit_on_close` functionality out from windowing and into app(?)
 - https://github.com/bevyengine/bevy/issues/5621
 - https://github.com/bevyengine/bevy/issues/7099
 - https://github.com/bevyengine/bevy/issues/7098


Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-01-19 00:38:28 +00:00
Zoey
4820917af6 Add set_if_neq method to DetectChanges trait (Rebased) (#6853)
# Objective

Change detection can be spuriously triggered by setting a field to the same value as before. As a result, a common pattern is to write:

```rust
if *foo != value {
  *foo = value;
}
```

This is confusing to read, and heavy on boilerplate.

Adopted from #5373, but untangled and rebased to current `bevy/main`.

## Solution

    1. Add a method to the `DetectChanges` trait that implements this boilerplate when the appropriate trait bounds are met.

    2. Document this minor footgun, and point users to it.


## Changelog

    * added the `set_if_neq` method to avoid triggering change detection when the new and previous values are equal. This will work on both components and resources.


## Migration Guide

If you are manually checking if a component or resource's value is equal to its new value before setting it to avoid triggering change detection, migrate to the clearer and more convenient `set_if_neq` method.
## Context

Related to #2363 as it avoids triggering change detection, but not a complete solution (as it still requires triggering it when real changes are made).



Co-authored-by: Zoey <Dessix@Dessix.net>
2022-12-11 19:24:19 +00:00
Edvin Kjell
aea4c5b1a4 [Fixes #6224] Add logging variants of system piping (#6751)
# Objective

Fixes #6224, add ``dbg``, ``info``, ``warn`` and ``error`` system piping adapter variants to expand #5776, which call the corresponding re-exported [bevy_log macros](https://docs.rs/bevy/latest/bevy/log/macro.info.html) when the result is an error.

## Solution

* Added ``dbg``, ``info``, ``warn`` and ``error`` system piping adapter variants to ``system_piping.rs``. 
* Modified and added tests for these under examples in ``system_piping.rs``.
2022-12-11 18:10:03 +00:00
Chia-Hsiang Cheng
585dac0582 Remove auto-margin properties from the examples (#6535)
# Objective

Fixes #6498.

## Solution

Adding a parent node with properties AlignItems::Center and JustifyContent::Center to centered child nodes and removing their auto-margin properties.
2022-11-21 14:38:35 +00:00
Hsiang-Cheng Yang
eaa35cf99f use Mul<f32> to double the value of Vec3 (#6607)
improve the example code
2022-11-14 23:08:30 +00:00
2ne1ugly
db0d7698e2 Change From<Icosphere> to TryFrom<Icosphere> (#6484)
# Objective

- Fixes  #6476

## Solution

- Return error instead of panic through `TryFrom`
- ~~Add `.except()` in examples~~ 
- Add `.unwrap()` in examples
2022-11-14 22:34:27 +00:00
targrub
96c9c60f80 Use cbrt() instead of powf(1./3.) (#6481)
# Objective

- Use cube root library function instead of handrolling.

## Solution

- Instead of `powf(1./3.)` use `cbrt()`.
2022-11-05 14:12:04 +00:00
Jakob Hellermann
e71c4d2802 fix nightly clippy warnings (#6395)
# Objective

- fix new clippy lints before they get stable and break CI

## Solution

- run `clippy --fix` to auto-fix machine-applicable lints
- silence `clippy::should_implement_trait` for `fn HandleId::default<T: Asset>`

## Changes
- always prefer `format!("{inline}")` over `format!("{}", not_inline)`
- prefer `Box::default` (or `Box::<T>::default` if necessary) over `Box::new(T::default())`
2022-10-28 21:03:01 +00:00
François
5622d56be1 Use plugin setup for resource only used at setup time (#6360)
# Objective

- Build on #6336 for more plugin configurations

## Solution

- `LogSettings`, `ImageSettings` and `DefaultTaskPoolOptions` are now plugins settings rather than resources

---

## Changelog

- `LogSettings` plugin settings have been move to `LogPlugin`, `ImageSettings` to `ImagePlugin` and `DefaultTaskPoolOptions` to `CorePlugin`

## Migration Guide

The `LogSettings` settings have been moved from a resource to `LogPlugin` configuration:

```rust
// Old (Bevy 0.8)
app
  .insert_resource(LogSettings {
    level: Level::DEBUG,
    filter: "wgpu=error,bevy_render=info,bevy_ecs=trace".to_string(),
  })
  .add_plugins(DefaultPlugins)

// New (Bevy 0.9)
app.add_plugins(DefaultPlugins.set(LogPlugin {
    level: Level::DEBUG,
    filter: "wgpu=error,bevy_render=info,bevy_ecs=trace".to_string(),
}))
```


The `ImageSettings` settings have been moved from a resource to `ImagePlugin` configuration:

```rust
// Old (Bevy 0.8)
app
  .insert_resource(ImageSettings::default_nearest())
  .add_plugins(DefaultPlugins)

// New (Bevy 0.9)
app.add_plugins(DefaultPlugins.set(ImagePlugin::default_nearest()))
```


The `DefaultTaskPoolOptions` settings have been moved from a resource to `CorePlugin::task_pool_options`:

```rust
// Old (Bevy 0.8)
app
  .insert_resource(DefaultTaskPoolOptions::with_num_threads(4))
  .add_plugins(DefaultPlugins)

// New (Bevy 0.9)
app.add_plugins(DefaultPlugins.set(CorePlugin {
  task_pool_options: TaskPoolOptions::with_num_threads(4),
}))
```
2022-10-25 22:19:34 +00:00
Cameron
7989cb2650 Add global time scaling (#5752)
# Objective

- Make `Time` API more consistent.
- Support time accel/decel/pause.

## Solution

This is just the `Time` half of #3002. I was told that part isn't controversial.

- Give the "delta time" and "total elapsed time" methods `f32`, `f64`, and `Duration` variants with consistent naming.
- Implement accelerating / decelerating the passage of time.
- Implement stopping time.

---

## Changelog

- Changed `time_since_startup` to `elapsed` because `time.time_*` is just silly.
- Added `relative_speed` and `set_relative_speed` methods.
- Added `is_paused`, `pause`, `unpause` , and methods. (I'd prefer `resume`, but `unpause` matches `Timer` API.)
- Added `raw_*` variants of the "delta time" and "total elapsed time" methods.
- Added `first_update` method because there's a non-zero duration between startup and the first update.

## Migration Guide

- `time.time_since_startup()` -> `time.elapsed()`
- `time.seconds_since_startup()` -> `time.elapsed_seconds_f64()`
- `time.seconds_since_startup_wrapped_f32()` -> `time.elapsed_seconds_wrapped()`

If you aren't sure which to use, most systems should continue to use "scaled" time (e.g. `time.delta_seconds()`). The realtime "unscaled" time measurements (e.g. `time.raw_delta_seconds()`) are mostly for debugging and profiling.
2022-10-22 18:52:29 +00:00
Lena Milizé
73605f43b6 Replace the bool argument of Timer with TimerMode (#6247)
As mentioned in #2926, it's better to have an explicit type that clearly communicates the intent of the timer mode rather than an opaque boolean, which can be only understood when knowing the signature or having to look up the documentation.

This also opens up a way to merge different timers, such as `Stopwatch`, and possibly future ones, such as `DiscreteStopwatch` and `DiscreteTimer` from #2683, into one struct.

Signed-off-by: Lena Milizé <me@lvmn.org>

# Objective

Fixes #2926.

## Solution

Introduce `TimerMode` which replaces the `bool` argument of `Timer` constructors. A `Default` value for `TimerMode` is `Once`.

---

## Changelog

### Added

- `TimerMode` enum, along with variants `TimerMode::Once` and `TimerMode::Repeating`

### Changed

- Replace `bool` argument of `Timer::new` and `Timer::from_seconds` with `TimerMode`
- Change `repeating: bool` field of `Timer` with `mode: TimerMode`

## Migration Guide

- Replace `Timer::new(duration, false)` with `Timer::new(duration, TimerMode::Once)`.
- Replace `Timer::new(duration, true)` with `Timer::new(duration, TimerMode::Repeating)`.
- Replace `Timer::from_seconds(seconds, false)` with `Timer::from_seconds(seconds, TimerMode::Once)`.
- Replace `Timer::from_seconds(seconds, true)` with `Timer::from_seconds(seconds, TimerMode::Repeating)`.
- Change `timer.repeating()` to `timer.mode() == TimerMode::Repeating`.
2022-10-17 13:47:01 +00:00
Alice Cecile
c0a93aa7a4 Rename system chaining to system piping (#6230)
# Objective

> System chaining is a confusing name: it implies the ability to construct non-linear graphs, and suggests a sense of system ordering that is only incidentally true. Instead, it actually works by passing data from one system to the next, much like the pipe operator.

> In the accepted [stageless RFC](https://github.com/bevyengine/rfcs/blob/main/rfcs/45-stageless.md), this concept is renamed to piping, and "system chaining" is used to construct groups of systems with ordering dependencies between them.

Fixes #6225.

## Changelog

System chaining has been renamed to system piping to improve clarity (and free up the name for new ordering APIs). 

## Migration Guide

The `.chain(handler_system)` method on systems is now `.pipe(handler_system)`.
The `IntoChainSystem` trait is now `IntoPipeSystem`, and the `ChainSystem` struct is now `PipeSystem`.
2022-10-11 15:21:12 +00:00
Carter Anderson
dc3f801239 Exclusive Systems Now Implement System. Flexible Exclusive System Params (#6083)
# Objective

The [Stageless RFC](https://github.com/bevyengine/rfcs/pull/45) involves allowing exclusive systems to be referenced and ordered relative to parallel systems. We've agreed that unifying systems under `System` is the right move.

This is an alternative to #4166 (see rationale in the comments I left there). Note that this builds on the learnings established there (and borrows some patterns).

## Solution

This unifies parallel and exclusive systems under the shared `System` trait, removing the old `ExclusiveSystem` trait / impls. This is accomplished by adding a new `ExclusiveFunctionSystem` impl similar to `FunctionSystem`. It is backed by `ExclusiveSystemParam`, which is similar to `SystemParam`. There is a new flattened out SystemContainer api (which cuts out a lot of trait and type complexity). 

This means you can remove all cases of `exclusive_system()`:

```rust
// before
commands.add_system(some_system.exclusive_system());
// after
commands.add_system(some_system);
```

I've also implemented `ExclusiveSystemParam` for `&mut QueryState` and `&mut SystemState`, which makes this possible in exclusive systems:

```rust
fn some_exclusive_system(
    world: &mut World,
    transforms: &mut QueryState<&Transform>,
    state: &mut SystemState<(Res<Time>, Query<&Player>)>,
) {
    for transform in transforms.iter(world) {
        println!("{transform:?}");
    }
    let (time, players) = state.get(world);
    for player in players.iter() {
        println!("{player:?}");
    }
}
```

Note that "exclusive function systems" assume `&mut World` is present (and the first param). I think this is a fair assumption, given that the presence of `&mut World` is what defines the need for an exclusive system.

I added some targeted SystemParam `static` constraints, which removed the need for this:
``` rust
fn some_exclusive_system(state: &mut SystemState<(Res<'static, Time>, Query<&'static Player>)>) {}
```

## Related

- #2923
- #3001
- #3946

## Changelog

- `ExclusiveSystem` trait (and implementations) has been removed in favor of sharing the `System` trait.
- `ExclusiveFunctionSystem` and `ExclusiveSystemParam` were added, enabling flexible exclusive function systems
- `&mut SystemState` and `&mut QueryState` now implement `ExclusiveSystemParam`
- Exclusive and parallel System configuration is now done via a unified `SystemDescriptor`, `IntoSystemDescriptor`, and `SystemContainer` api.

## Migration Guide

Calling `.exclusive_system()` is no longer required (or supported) for converting exclusive system functions to exclusive systems:

```rust
// Old (0.8)
app.add_system(some_exclusive_system.exclusive_system());
// New (0.9)
app.add_system(some_exclusive_system);
```

Converting "normal" parallel systems to exclusive systems is done by calling the exclusive ordering apis:

```rust
// Old (0.8)
app.add_system(some_system.exclusive_system().at_end());
// New (0.9)
app.add_system(some_system.at_end());
```

Query state in exclusive systems can now be cached via ExclusiveSystemParams, which should be preferred for clarity and performance reasons:
```rust
// Old (0.8)
fn some_system(world: &mut World) {
  let mut transforms = world.query::<&Transform>();
  for transform in transforms.iter(world) {
  }
}
// New (0.9)
fn some_system(world: &mut World, transforms: &mut QueryState<&Transform>) {
  for transform in transforms.iter(world) {
  }
}
```
2022-09-26 23:57:07 +00:00
Alice Cecile
481eec2c92 Rename UiColor to BackgroundColor (#6087)
# Objective

Fixes #6078. The `UiColor` component is unhelpfully named: it is unclear, ambiguous with border color and 

## Solution

Rename the `UiColor` component (and associated fields) to `BackgroundColor` / `background_colorl`.

## Migration Guide

`UiColor` has been renamed to `BackgroundColor`. This change affects `NodeBundle`, `ButtonBundle` and `ImageBundle`. In addition, the corresponding field on `ExtractedUiNode` has been renamed to `background_color` for consistency.
2022-09-25 00:39:17 +00:00
Carter Anderson
01aedc8431 Spawn now takes a Bundle (#6054)
# Objective

Now that we can consolidate Bundles and Components under a single insert (thanks to #2975 and #6039), almost 100% of world spawns now look like `world.spawn().insert((Some, Tuple, Here))`. Spawning an entity without any components is an extremely uncommon pattern, so it makes sense to give spawn the "first class" ergonomic api. This consolidated api should be made consistent across all spawn apis (such as World and Commands).

## Solution

All `spawn` apis (`World::spawn`, `Commands:;spawn`, `ChildBuilder::spawn`, and `WorldChildBuilder::spawn`) now accept a bundle as input:

```rust
// before:
commands
  .spawn()
  .insert((A, B, C));
world
  .spawn()
  .insert((A, B, C);

// after
commands.spawn((A, B, C));
world.spawn((A, B, C));
```

All existing instances of `spawn_bundle` have been deprecated in favor of the new `spawn` api. A new `spawn_empty` has been added, replacing the old `spawn` api.  

By allowing `world.spawn(some_bundle)` to replace `world.spawn().insert(some_bundle)`, this opened the door to removing the initial entity allocation in the "empty" archetype / table done in `spawn()` (and subsequent move to the actual archetype in `.insert(some_bundle)`).

This improves spawn performance by over 10%:
![image](https://user-images.githubusercontent.com/2694663/191627587-4ab2f949-4ccd-4231-80eb-80dd4d9ad6b9.png)

To take this measurement, I added a new `world_spawn` benchmark.

Unfortunately, optimizing `Commands::spawn` is slightly less trivial, as Commands expose the Entity id of spawned entities prior to actually spawning. Doing the optimization would (naively) require assurances that the `spawn(some_bundle)` command is applied before all other commands involving the entity (which would not necessarily be true, if memory serves). Optimizing `Commands::spawn` this way does feel possible, but it will require careful thought (and maybe some additional checks), which deserves its own PR. For now, it has the same performance characteristics of the current `Commands::spawn_bundle` on main.

**Note that 99% of this PR is simple renames and refactors. The only code that needs careful scrutiny is the new `World::spawn()` impl, which is relatively straightforward, but it has some new unsafe code (which re-uses battle tested BundlerSpawner code path).** 

---

## Changelog

- All `spawn` apis (`World::spawn`, `Commands:;spawn`, `ChildBuilder::spawn`, and `WorldChildBuilder::spawn`) now accept a bundle as input
- All instances of `spawn_bundle` have been deprecated in favor of the new `spawn` api
- World and Commands now have `spawn_empty()`, which is equivalent to the old `spawn()` behavior.  

## Migration Guide

```rust
// Old (0.8):
commands
  .spawn()
  .insert_bundle((A, B, C));
// New (0.9)
commands.spawn((A, B, C));

// Old (0.8):
commands.spawn_bundle((A, B, C));
// New (0.9)
commands.spawn((A, B, C));

// Old (0.8):
let entity = commands.spawn().id();
// New (0.9)
let entity = commands.spawn_empty().id();

// Old (0.8)
let entity = world.spawn().id();
// New (0.9)
let entity = world.spawn_empty();
```
2022-09-23 19:55:54 +00:00
Carter Anderson
cd15f0f5be Accept Bundles for insert and remove. Deprecate insert/remove_bundle (#6039)
# Objective

Take advantage of the "impl Bundle for Component" changes in #2975 / add the follow up changes discussed there.

## Solution

- Change `insert` and `remove` to accept a Bundle instead of a Component (for both Commands and World)
- Deprecate `insert_bundle`, `remove_bundle`, and `remove_bundle_intersection`
- Add `remove_intersection`

---

## Changelog

- Change `insert` and `remove` now accept a Bundle instead of a Component (for both Commands and World)
- `insert_bundle` and `remove_bundle` are deprecated
 

## Migration Guide

Replace `insert_bundle` with `insert`:
```rust
// Old (0.8)
commands.spawn().insert_bundle(SomeBundle::default());
// New (0.9)
commands.spawn().insert(SomeBundle::default());
```

Replace `remove_bundle` with `remove`:
```rust
// Old (0.8)
commands.entity(some_entity).remove_bundle::<SomeBundle>();
// New (0.9)
commands.entity(some_entity).remove::<SomeBundle>();
```

Replace `remove_bundle_intersection` with `remove_intersection`:
```rust
// Old (0.8)
world.entity_mut(some_entity).remove_bundle_intersection::<SomeBundle>();
// New (0.9)
world.entity_mut(some_entity).remove_intersection::<SomeBundle>();
```

Consider consolidating as many operations as possible to improve ergonomics and cut down on archetype moves:
```rust
// Old (0.8)
commands.spawn()
  .insert_bundle(SomeBundle::default())
  .insert(SomeComponent);

// New (0.9) - Option 1
commands.spawn().insert((
  SomeBundle::default(),
  SomeComponent,
))

// New (0.9) - Option 2
commands.spawn_bundle((
  SomeBundle::default(),
  SomeComponent,
))
```

## Next Steps

Consider changing `spawn` to accept a bundle and deprecate `spawn_bundle`.
2022-09-21 21:47:53 +00:00
Daniel McNab
1a2aedd165 Implement Bundle for Component. Use Bundle tuples for insertion (#2975)
@BoxyUwU this is your fault. 

Also cart didn't arrive in time to tell us not to do this.

# Objective

- Fix #2974

## Solution

- The first commit just does the actual change
- Follow up commits do steps to prove that this method works to unify as required, but this does not remove `insert_bundle`.

## Changelog

### Changed
Nested bundles now collapse automatically, and every `Component` now implements `Bundle`.
This means that you can combine bundles and components arbitrarily, for example:
```rust
// before:
.insert(A).insert_bundle(MyBBundle{..})
// after:
.insert_bundle((A, MyBBundle {..}))
```

Note that there will be a follow up PR that removes the current `insert` impl and renames `insert_bundle` to `insert`.

### Removed
The `bundle` attribute in `derive(Bundle)`.

## Migration guide

In `derive(Bundle)`, the `bundle` attribute has been removed. Nested bundles are not collapsed automatically. You should remove `#[bundle]` attributes.

Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2022-09-20 20:17:08 +00:00
ira
76ae6f4c6e Miscellaneous code-quality improvements. (#5860)
Does what it do.

Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-09-05 00:30:21 +00:00
JoJoJet
697d297b55 Remove last uses of string-labels (#5420)
# Objective

* Related: #4341
* Remove all remaining uses of stringly-typed labels in the repo. Right now, it's just a bunch of tests and examples.
2022-09-03 18:06:41 +00:00
ira
b42f426fc3 Add associated constant IDENTITY to Transform and friends. (#5340)
# Objective
Since `identity` is a const fn that takes no arguments it seems logical to make it an associated constant.
This is also more in line with types from glam (eg. `Quat::IDENTITY`).

## Migration Guide

The method `identity()` on `Transform`, `GlobalTransform` and `TransformBundle` has been deprecated.
Use the associated constant `IDENTITY` instead.

Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-08-30 22:10:24 +00:00
ira
65252bb87a Consistently use PI to specify angles in examples. (#5825)
Examples inconsistently use either `TAU`, `PI`, `FRAC_PI_2` or `FRAC_PI_4`.
Often in odd ways and without `use`ing the constants, making it difficult to parse.

 * Use `PI` to specify angles.
 * General code-quality improvements.
 * Fix borked `hierarchy` example.


Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-08-30 19:52:11 +00:00
ira
992681b59b Make Resource trait opt-in, requiring #[derive(Resource)] V2 (#5577)
*This PR description is an edited copy of #5007, written by @alice-i-cecile.*
# Objective
Follow-up to https://github.com/bevyengine/bevy/pull/2254. The `Resource` trait currently has a blanket implementation for all types that meet its bounds.

While ergonomic, this results in several drawbacks:

* it is possible to make confusing, silent mistakes such as inserting a function pointer (Foo) rather than a value (Foo::Bar) as a resource
* it is challenging to discover if a type is intended to be used as a resource
* we cannot later add customization options (see the [RFC](https://github.com/bevyengine/rfcs/blob/main/rfcs/27-derive-component.md) for the equivalent choice for Component).
* dependencies can use the same Rust type as a resource in invisibly conflicting ways
* raw Rust types used as resources cannot preserve privacy appropriately, as anyone able to access that type can read and write to internal values
* we cannot capture a definitive list of possible resources to display to users in an editor
## Notes to reviewers
 * Review this commit-by-commit; there's effectively no back-tracking and there's a lot of churn in some of these commits.
   *ira: My commits are not as well organized :')*
 * I've relaxed the bound on Local to Send + Sync + 'static: I don't think these concerns apply there, so this can keep things simple. Storing e.g. a u32 in a Local is fine, because there's a variable name attached explaining what it does.
 * I think this is a bad place for the Resource trait to live, but I've left it in place to make reviewing easier. IMO that's best tackled with https://github.com/bevyengine/bevy/issues/4981.

## Changelog
`Resource` is no longer automatically implemented for all matching types. Instead, use the new `#[derive(Resource)]` macro.

## Migration Guide
Add `#[derive(Resource)]` to all types you are using as a resource.

If you are using a third party type as a resource, wrap it in a tuple struct to bypass orphan rules. Consider deriving `Deref` and `DerefMut` to improve ergonomics.

`ClearColor` no longer implements `Component`. Using `ClearColor` as a component in 0.8 did nothing.
Use the `ClearColorConfig` in the `Camera3d` and `Camera2d` components instead.


Co-authored-by: Alice <alice.i.cecile@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: devil-ira <justthecooldude@gmail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2022-08-08 21:36:35 +00:00