## Objective
Currently, events are dropped after two frames. This cadence wasn't
*chosen* for a specific reason, double buffering just lets events
persist for at least two frames. Events only need to be dropped at a
predictable point so that the event queues don't grow forever (i.e.
events should never cause a memory leak).
Events (and especially input events) need to be observable by systems in
`FixedUpdate`, but as-is events are dropped before those systems even
get a chance to see them.
## Solution
Instead of unconditionally dropping events in `First`, require
`FixedUpdate` to first queue the buffer swap (if the `TimePlugin` has
been installed). This way, events are only dropped after a frame that
runs `FixedUpdate`.
## Future Work
In the same way we have independent copies of `Time` for tracking time
in `Main` and `FixedUpdate`, we will need independent copies of `Input`
for tracking press/release status correctly in `Main` and `FixedUpdate`.
--
Every run of `FixedUpdate` covers a specific timespan. For example, if
the fixed timestep `Δt` is 10ms, the first three `FixedUpdate` runs
cover `[0ms, 10ms)`, `[10ms, 20ms)`, and `[20ms, 30ms)`.
`FixedUpdate` can run many times in one frame. For truly
framerate-independent behavior, each `FixedUpdate` should only see the
events that occurred in its covered timespan, but what happens right now
is the first step in the frame reads all pending events.
Fixing that will require timestamped events.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
- Standardize fmt for toml files
## Solution
- Add [taplo](https://taplo.tamasfe.dev/) to CI (check for fmt and diff
for toml files), for context taplo is used by the most popular extension
in VScode [Even Better
TOML](https://marketplace.visualstudio.com/items?itemName=tamasfe.even-better-toml
- Add contribution section to explain toml fmt with taplo.
Now to pass CI you need to run `taplo fmt --option indent_string=" "` or
if you use vscode have the `Even Better TOML` extension with 4 spaces
for indent
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
- Fix adding `#![allow(clippy::type_complexity)]` everywhere. like #9796
## Solution
- Use the new [lints] table that will land in 1.74
(https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#lints)
- inherit lint to the workspace, crates and examples.
```
[lints]
workspace = true
```
## Changelog
- Bump rust version to 1.74
- Enable lints table for the workspace
```toml
[workspace.lints.clippy]
type_complexity = "allow"
```
- Allow type complexity for all crates and examples
```toml
[lints]
workspace = true
```
---------
Co-authored-by: Martín Maita <47983254+mnmaita@users.noreply.github.com>
# Objective
There is no easy way to discard some amount for `Time<Fixed>`'s
overstep. This can be useful for online games when the client receives
information about a tick (which happens when you get a FPS drop or the
ping changes for example) it has not yet processed, it can discard
overstep equal to the number of ticks it can jump ahead.
Currently the workaround would be to create a new `Time<Fixed>` copy the
old timestep, advance it by the overstep amount that would remain after
subtracting the discarded amount, and using `.context_mut()` to
overwrite the old context with the new one. If you overwrite the whole
`Time<Fixed>` or forget to copy over the timestep you can introduce
undesirable side effects.
## Solution
Introduce a `discard_overstep` method, which discards the provided
amount of overstep. It uses satuarting_sub to avoid errors (negative
`Duration`s do not exist).
---
## Changelog
- Added `discard_overstep` function to `Time<Fixed>`
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Fixes#10439
`Timer::percent()` and `Timer::percent_left()` return values in the
range of 0.0 to 1.0, even though their names contain "percent".
These functions should be renamed for clarity.
## Solution
- Rename `Timer::percent()` to `Timer::fraction()`
- Rename `Timer::percent_left()` to `Timer::fraction_remaining()`
---
## Changelog
### Changed
- Renamed `Timer::percent()` to `Timer::fraction()`
- Renamed `Timer::percent_left()` to `Timer::fraction_remaining()`
## Migration Guide
- `Timer::percent()` has been renamed to `Timer::fraction()`
- `Timer::percent_left()` has been renamed to
`Timer::fraction_remaining()`
# Objective
This is similar to #10439.
`Time::<Fixed>::overstep_percentage()` and
`Time::<Fixed>::overstep_percentage_f64()` returns values from 0.0 to
1.0, but their names use the word "percentage". These function names
make it easy to misunderstand that they return values from 0.0 to 100.0.
To avoid confusion, these functions should be renamed to
"`overstep_fraction(_f64)`".
## Solution
Rename them.
---
## Changelog
### Changed
- Renamed `Time::<Fixed>::overstep_percentage()` to
`Time::<Fixed>::overstep_fraction()`
- Renamed `Time::<Fixed>::overstep_percentage_f64()` to
`Time::<Fixed>::overstep_fraction_f64()`
## Migration Guide
- `Time::<Fixed>::overstep_percentage()` has been renamed to
`Time::<Fixed>::overstep_fraction()`
- `Time::<Fixed>::overstep_percentage_f64()` has been renamed to
`Time::<Fixed>::overstep_fraction_f64()`
Preparing next release
This PR has been auto-generated
---------
Co-authored-by: Bevy Auto Releaser <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: François <mockersf@gmail.com>
# Objective
Fixes#10177 .
## Solution
Added a new run condition and tweaked the docs for `on_timer`.
## Changelog
### Added
- `on_real_time_timer` run condition
# Objective
Time clamping happens consistently for apps that load non-trivial
things. While this _is_ an indicator that we should probably try to move
this work to a thread that doesn't block the Update, this is common
enough (and unactionable enough) that I think we should demote it for
now.
```
2023-10-16T18:46:14.918781Z WARN bevy_time::virt: delta time larger than maximum delta, clamping delta to 250ms and skipping 63.649253ms
2023-10-16T18:46:15.178048Z WARN bevy_time::virt: delta time larger than maximum delta, clamping delta to 250ms and skipping 1.71611ms
```
## Solution
Change `warn` to `debug` for this message
# Objective
Current `FixedTime` and `Time` have several problems. This pull aims to
fix many of them at once.
- If there is a longer pause between app updates, time will jump forward
a lot at once and fixed time will iterate on `FixedUpdate` for a large
number of steps. If the pause is merely seconds, then this will just
mean jerkiness and possible unexpected behaviour in gameplay. If the
pause is hours/days as with OS suspend, the game will appear to freeze
until it has caught up with real time.
- If calculating a fixed step takes longer than specified fixed step
period, the game will enter a death spiral where rendering each frame
takes longer and longer due to more and more fixed step updates being
run per frame and the game appears to freeze.
- There is no way to see current fixed step elapsed time inside fixed
steps. In order to track this, the game designer needs to add a custom
system inside `FixedUpdate` that calculates elapsed or step count in a
resource.
- Access to delta time inside fixed step is `FixedStep::period` rather
than `Time::delta`. This, coupled with the issue that `Time::elapsed`
isn't available at all for fixed steps, makes it that time requiring
systems are either implemented to be run in `FixedUpdate` or `Update`,
but rarely work in both.
- Fixes#8800
- Fixes#8543
- Fixes#7439
- Fixes#5692
## Solution
- Create a generic `Time<T>` clock that has no processing logic but
which can be instantiated for multiple usages. This is also exposed for
users to add custom clocks.
- Create three standard clocks, `Time<Real>`, `Time<Virtual>` and
`Time<Fixed>`, all of which contain their individual logic.
- Create one "default" clock, which is just `Time` (or `Time<()>`),
which will be overwritten from `Time<Virtual>` on each update, and
`Time<Fixed>` inside `FixedUpdate` schedule. This way systems that do
not care specifically which time they track can work both in `Update`
and `FixedUpdate` without changes and the behaviour is intuitive.
- Add `max_delta` to virtual time update, which limits how much can be
added to virtual time by a single update. This fixes both the behaviour
after a long freeze, and also the death spiral by limiting how many
fixed timestep iterations there can be per update. Possible future work
could be adding `max_accumulator` to add a sort of "leaky bucket" time
processing to possibly smooth out jumps in time while keeping frame rate
stable.
- Many minor tweaks and clarifications to the time functions and their
documentation.
## Changelog
- `Time::raw_delta()`, `Time::raw_elapsed()` and related methods are
moved to `Time<Real>::delta()` and `Time<Real>::elapsed()` and now match
`Time` API
- `FixedTime` is now `Time<Fixed>` and matches `Time` API.
- `Time<Fixed>` default timestep is now 64 Hz, or 15625 microseconds.
- `Time` inside `FixedUpdate` now reflects fixed timestep time, making
systems portable between `Update ` and `FixedUpdate`.
- `Time::pause()`, `Time::set_relative_speed()` and related methods must
now be called as `Time<Virtual>::pause()` etc.
- There is a new `max_delta` setting in `Time<Virtual>` that limits how
much the clock can jump by a single update. The default value is 0.25
seconds.
- Removed `on_fixed_timer()` condition as `on_timer()` does the right
thing inside `FixedUpdate` now.
## Migration Guide
- Change all `Res<Time>` instances that access `raw_delta()`,
`raw_elapsed()` and related methods to `Res<Time<Real>>` and `delta()`,
`elapsed()`, etc.
- Change access to `period` from `Res<FixedTime>` to `Res<Time<Fixed>>`
and use `delta()`.
- The default timestep has been changed from 60 Hz to 64 Hz. If you wish
to restore the old behaviour, use
`app.insert_resource(Time::<Fixed>::from_hz(60.0))`.
- Change `app.insert_resource(FixedTime::new(duration))` to
`app.insert_resource(Time::<Fixed>::from_duration(duration))`
- Change `app.insert_resource(FixedTime::new_from_secs(secs))` to
`app.insert_resource(Time::<Fixed>::from_seconds(secs))`
- Change `system.on_fixed_timer(duration)` to
`system.on_timer(duration)`. Timers in systems placed in `FixedUpdate`
schedule automatically use the fixed time clock.
- Change `ResMut<Time>` calls to `pause()`, `is_paused()`,
`set_relative_speed()` and related methods to `ResMut<Time<Virtual>>`
calls. The API is the same, with the exception that `relative_speed()`
will return the actual last ste relative speed, while
`effective_relative_speed()` returns 0.0 if the time is paused and
corresponds to the speed that was set when the update for the current
frame started.
## Todo
- [x] Update pull name and description
- [x] Top level documentation on usage
- [x] Fix examples
- [x] Decide on default `max_delta` value
- [x] Decide naming of the three clocks: is `Real`, `Virtual`, `Fixed`
good?
- [x] Decide if the three clock inner structures should be in prelude
- [x] Decide on best way to configure values at startup: is manually
inserting a new clock instance okay, or should there be config struct
separately?
- [x] Fix links in docs
- [x] Decide what should be public and what not
- [x] Decide how `wrap_period` should be handled when it is changed
- [x] ~~Add toggles to disable setting the clock as default?~~ No,
separate pull if needed.
- [x] Add tests
- [x] Reformat, ensure adheres to conventions etc.
- [x] Build documentation and see that it looks correct
## Contributors
Huge thanks to @alice-i-cecile and @maniwani while building this pull.
It was a shared effort!
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Cameron <51241057+maniwani@users.noreply.github.com>
Co-authored-by: Jerome Humbert <djeedai@gmail.com>
# Objective
- sometimes when bevy shuts down on certain machines the render thread
tries to send the time after the main world has been dropped.
- fixes an error mentioned in a reply in
https://github.com/bevyengine/bevy/issues/9543
---
## Changelog
- ignore disconnected errors from the time channel.
# Objective
I was wondering whether to use `Timer::finished` or
`Timer::just_finished` for my repeating timer. This PR clarifies their
difference (or rather, lack thereof).
## Solution
More docs & examples.
# Objective
- Move schedule name into `Schedule` to allow the schedule name to be
used for errors and tracing in Schedule methods
- Fixes#9510
## Solution
- Move label onto `Schedule` and adjust api's on `World` and `Schedule`
to not pass explicit label where it makes sense to.
- add name to errors and tracing.
- `Schedule::new` now takes a label so either add the label or use
`Schedule::default` which uses a default label. `default` is mostly used
in doc examples and tests.
---
## Changelog
- move label onto `Schedule` to improve error message and logging for
schedules.
## Migration Guide
`Schedule::new` and `App::add_schedule`
```rust
// old
let schedule = Schedule::new();
app.add_schedule(MyLabel, schedule);
// new
let schedule = Schedule::new(MyLabel);
app.add_schedule(schedule);
```
if you aren't using a label and are using the schedule struct directly
you can use the default constructor.
```rust
// old
let schedule = Schedule::new();
schedule.run(world);
// new
let schedule = Schedule::default();
schedule.run(world);
```
`Schedules:insert`
```rust
// old
let schedule = Schedule::new();
schedules.insert(MyLabel, schedule);
// new
let schedule = Schedule::new(MyLabel);
schedules.insert(schedule);
```
`World::add_schedule`
```rust
// old
let schedule = Schedule::new();
world.add_schedule(MyLabel, schedule);
// new
let schedule = Schedule::new(MyLabel);
world.add_schedule(schedule);
```
CI-capable version of #9086
---------
Co-authored-by: Bevy Auto Releaser <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: François <mockersf@gmail.com>
I created this manually as Github didn't want to run CI for the
workflow-generated PR. I'm guessing we didn't hit this in previous
releases because we used bors.
Co-authored-by: Bevy Auto Releaser <41898282+github-actions[bot]@users.noreply.github.com>
# Objective
**This implementation is based on
https://github.com/bevyengine/rfcs/pull/59.**
---
Resolves#4597
Full details and motivation can be found in the RFC, but here's a brief
summary.
`FromReflect` is a very powerful and important trait within the
reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to
be formed into Real ones (e.g., `Vec<i32>`, etc.).
This mainly comes into play concerning deserialization, where the
reflection deserializers both return a `Box<dyn Reflect>` that almost
always contain one of these Dynamic representations of a Real type. To
convert this to our Real type, we need to use `FromReflect`.
It also sneaks up in other ways. For example, it's a required bound for
`T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`.
It's also required by all fields of an enum as it's used as part of the
`Reflect::apply` implementation.
So in other words, much like `GetTypeRegistration` and `Typed`, it is
very much a core reflection trait.
The problem is that it is not currently treated like a core trait and is
not automatically derived alongside `Reflect`. This makes using it a bit
cumbersome and easy to forget.
## Solution
Automatically derive `FromReflect` when deriving `Reflect`.
Users can then choose to opt-out if needed using the
`#[reflect(from_reflect = false)]` attribute.
```rust
#[derive(Reflect)]
struct Foo;
#[derive(Reflect)]
#[reflect(from_reflect = false)]
struct Bar;
fn test<T: FromReflect>(value: T) {}
test(Foo); // <-- OK
test(Bar); // <-- Panic! Bar does not implement trait `FromReflect`
```
#### `ReflectFromReflect`
This PR also automatically adds the `ReflectFromReflect` (introduced in
#6245) registration to the derived `GetTypeRegistration` impl— if the
type hasn't opted out of `FromReflect` of course.
<details>
<summary><h4>Improved Deserialization</h4></summary>
> **Warning**
> This section includes changes that have since been descoped from this
PR. They will likely be implemented again in a followup PR. I am mainly
leaving these details in for archival purposes, as well as for reference
when implementing this logic again.
And since we can do all the above, we might as well improve
deserialization. We can now choose to deserialize into a Dynamic type or
automatically convert it using `FromReflect` under the hood.
`[Un]TypedReflectDeserializer::new` will now perform the conversion and
return the `Box`'d Real type.
`[Un]TypedReflectDeserializer::new_dynamic` will work like what we have
now and simply return the `Box`'d Dynamic type.
```rust
// Returns the Real type
let reflect_deserializer = UntypedReflectDeserializer::new(®istry);
let mut deserializer = ron:🇩🇪:Deserializer::from_str(input)?;
let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?;
// Returns the Dynamic type
let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(®istry);
let mut deserializer = ron:🇩🇪:Deserializer::from_str(input)?;
let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?;
```
</details>
---
## Changelog
* `FromReflect` is now automatically derived within the `Reflect` derive
macro
* This includes auto-registering `ReflectFromReflect` in the derived
`GetTypeRegistration` impl
* ~~Renamed `TypedReflectDeserializer::new` and
`UntypedReflectDeserializer::new` to
`TypedReflectDeserializer::new_dynamic` and
`UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped**
* ~~Changed `TypedReflectDeserializer::new` and
`UntypedReflectDeserializer::new` to automatically convert the
deserialized output using `FromReflect`~~ **Descoped**
## Migration Guide
* `FromReflect` is now automatically derived within the `Reflect` derive
macro. Items with both derives will need to remove the `FromReflect`
one.
```rust
// OLD
#[derive(Reflect, FromReflect)]
struct Foo;
// NEW
#[derive(Reflect)]
struct Foo;
```
If using a manual implementation of `FromReflect` and the `Reflect`
derive, users will need to opt-out of the automatic implementation.
```rust
// OLD
#[derive(Reflect)]
struct Foo;
impl FromReflect for Foo {/* ... */}
// NEW
#[derive(Reflect)]
#[reflect(from_reflect = false)]
struct Foo;
impl FromReflect for Foo {/* ... */}
```
<details>
<summary><h4>Removed Migrations</h4></summary>
> **Warning**
> This section includes changes that have since been descoped from this
PR. They will likely be implemented again in a followup PR. I am mainly
leaving these details in for archival purposes, as well as for reference
when implementing this logic again.
* The reflect deserializers now perform a `FromReflect` conversion
internally. The expected output of `TypedReflectDeserializer::new` and
`UntypedReflectDeserializer::new` is no longer a Dynamic (e.g.,
`DynamicList`), but its Real counterpart (e.g., `Vec<i32>`).
```rust
let reflect_deserializer =
UntypedReflectDeserializer::new_dynamic(®istry);
let mut deserializer = ron:🇩🇪:Deserializer::from_str(input)?;
// OLD
let output: DynamicStruct = reflect_deserializer.deserialize(&mut
deserializer)?.take()?;
// NEW
let output: SomeStruct = reflect_deserializer.deserialize(&mut
deserializer)?.take()?;
```
Alternatively, if this behavior isn't desired, use the
`TypedReflectDeserializer::new_dynamic` and
`UntypedReflectDeserializer::new_dynamic` methods instead:
```rust
// OLD
let reflect_deserializer = UntypedReflectDeserializer::new(®istry);
// NEW
let reflect_deserializer =
UntypedReflectDeserializer::new_dynamic(®istry);
```
</details>
---------
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- I want to take screenshots of examples in CI to help with validation
of changes
## Solution
- Can override how much time is updated per frame
- Can specify on which frame to take a screenshots
- Save screenshots in CI
I reused the `TimeUpdateStrategy::ManualDuration` to be able to set the
time update strategy to a fixed duration every frame. Its previous
meaning didn't make much sense to me. This change makes it possible to
have screenshots that are exactly the same across runs.
If this gets merged, I'll add visual comparison of screenshots between
runs to ensure nothing gets broken
## Migration Guide
* `TimeUpdateStrategy::ManualDuration` meaning has changed. Instead of
setting time to `Instant::now()` plus the given duration, it sets time
to last update plus the given duration.
# Objective
Timer with zero `Duration` panics at `tick()` because of division by
zero. This PR Fixes#8463 .
## Solution
- Handle division by zero separately with `checked_div` and
`checked_rem`.
---
## Changelog
- Replace division with `checked_div`. Set `times_finished_this_tick` to
u32::MAX when duration is zero.
- Set `elapsed` to `Duration::ZERO` when timer duration is zero.
- Set `percent` to `1.0` when duration is zero.
- `times_finished_this_tick` is [not used
anywhere](https://github.com/bevyengine/bevy/search?q=times_finished_this_tick),
that's why this change will not affect other parts of the project.
- `times_finished_this_tick` is set to `0` after `reset()` and before
first `tick()` call.
# Objective
If you want to execute a schedule on the world using arbitrarily complex
behavior, you currently need to use "hokey-pokey strats": remove the
schedule from the world, do your thing, and add it back to the world.
Not only is this cumbersome, it's potentially error-prone as one might
forget to re-insert the schedule.
## Solution
Add the `World::{try}schedule_scope{ref}` family of functions, which is
a convenient abstraction over hokey pokey strats. This method
essentially works the same way as `World::resource_scope`.
### Example
```rust
// Run the schedule five times.
world.schedule_scope(MySchedule, |world, schedule| {
for _ in 0..5 {
schedule.run(world);
}
});
```
---
## Changelog
Added the `World::schedule_scope` family of methods, which provide a way
to get mutable access to a world and one of its schedules at the same
time.
---------
Co-authored-by: James Liu <contact@jamessliu.com>
# Objective
The clippy lint `type_complexity` is known not to play well with bevy.
It frequently triggers when writing complex queries, and taking the
lint's advice of using a type alias almost always just obfuscates the
code with no benefit. Because of this, this lint is currently ignored in
CI, but unfortunately it still shows up when viewing bevy code in an
IDE.
As someone who's made a fair amount of pull requests to this repo, I
will say that this issue has been a consistent thorn in my side. Since
bevy code is filled with spurious, ignorable warnings, it can be very
difficult to spot the *real* warnings that must be fixed -- most of the
time I just ignore all warnings, only to later find out that one of them
was real after I'm done when CI runs.
## Solution
Suppress this lint in all bevy crates. This was previously attempted in
#7050, but the review process ended up making it more complicated than
it needs to be and landed on a subpar solution.
The discussion in https://github.com/rust-lang/rust-clippy/pull/10571
explores some better long-term solutions to this problem. Since there is
no timeline on when these solutions may land, we should resolve this
issue in the meantime by locally suppressing these lints.
### Unresolved issues
Currently, these lints are not suppressed in our examples, since that
would require suppressing the lint in every single source file. They are
still ignored in CI.
# Objective
Fixes#7864
## Solution
Add the run conditions described in the issue. Also needed to add `bevy` as a dev dependency to `bevy_time` so the doctests can run.
---
## Changelog
- Add `on_timer` and `on_fixed_timer` run conditions
# Objective
-0.0 should typically be treated exactly the same as 0.0, but this assertion was rejecting it while allowing 0.0. The `Duration` API handles this correctly (on recent Rust versions) and returns a zero `Duration` for both -0.0 and 0.0.
## Solution
Check for `ratio >= 0.0`, which is true if `ratio` is `-0.0`.
---
## Changelog
Allow relative speed of -0.0 in the `Time::set_relative_speed_fXX` methods.
# 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
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.
# Objective
Complete the first part of the migration detailed in bevyengine/rfcs#45.
## Solution
Add all the new stuff.
### TODO
- [x] Impl tuple methods.
- [x] Impl chaining.
- [x] Port ambiguity detection.
- [x] Write docs.
- [x] ~~Write more tests.~~(will do later)
- [ ] Write changelog and examples here?
- [x] ~~Replace `petgraph`.~~ (will do later)
Co-authored-by: james7132 <contact@jamessliu.com>
Co-authored-by: Michael Hsu <mike.hsu@gmail.com>
Co-authored-by: Mike Hsu <mike.hsu@gmail.com>
When I was upgrading to 0.9 noticed there were some changes to the timer, mainly the `TimerMode`. When switching from the old `is_repeating()` and `set_repeating()` to the new `mode()` and `set_mode()` noticed the docs still had the old description.
# Objective
Right now, the `TaskPool` implementation allows panics to permanently kill worker threads upon panicking. This is currently non-recoverable without using a `std::panic::catch_unwind` in every scheduled task. This is poor ergonomics and even poorer developer experience. This is exacerbated by #2250 as these threads are global and cannot be replaced after initialization.
Removes the need for temporary fixes like #4998. Fixes#4996. Fixes#6081. Fixes#5285. Fixes#5054. Supersedes #2307.
## Solution
The current solution is to wrap `Executor::run` in `TaskPool` with a `catch_unwind`, and discarding the potential panic. This was taken straight from [smol](404c7bcc0a/src/spawn.rs (L44))'s current implementation. ~~However, this is not entirely ideal as:~~
- ~~the signaled to the awaiting task. We would need to change `Task<T>` to use `async_task::FallibleTask` internally, and even then it doesn't signal *why* it panicked, just that it did.~~ (See below).
- ~~no error is logged of any kind~~ (See below)
- ~~it's unclear if it drops other tasks in the executor~~ (it does not)
- ~~This allows the ECS parallel executor to keep chugging even though a system's task has been dropped. This inevitably leads to deadlock in the executor.~~ Assuming we don't catch the unwind in ParallelExecutor, this will naturally kill the main thread.
### Alternatives
A final solution likely will incorporate elements of any or all of the following.
#### ~~Log and Ignore~~
~~Log the panic, drop the task, keep chugging. This only addresses the discoverability of the panic. The process will continue to run, probably deadlocking the executor. tokio's detatched tasks operate in this fashion.~~
Panics already do this by default, even when caught by `catch_unwind`.
#### ~~`catch_unwind` in `ParallelExecutor`~~
~~Add another layer catching system-level panics into the `ParallelExecutor`. How the executor continues when a core dependency of many systems fails to run is up for debate.~~
`async_task::Task` bubbles up panics already, this will transitively push panics all the way to the main thread.
#### ~~Emulate/Copy `tokio::JoinHandle` with `Task<T>`~~
~~`tokio::JoinHandle<T>` bubbles up the panic from the underlying task when awaited. This can be transitively applied across other APIs that also use `Task<T>` like `Query::par_for_each` and `TaskPool::scope`, bubbling up the panic until it's either caught or it reaches the main thread.~~
`async_task::Task` bubbles up panics already, this will transitively push panics all the way to the main thread.
#### Abort on Panic
The nuclear option. Log the error, abort the entire process on any thread in the task pool panicking. Definitely avoids any additional infrastructure for passing the panic around, and might actually lead to more efficient code as any unwinding is optimized out. However gives the developer zero options for dealing with the issue, a seemingly poor choice for debuggability, and prevents graceful shutdown of the process. Potentially an option for handling very low-level task management (a la #4740). Roughly takes the shape of:
```rust
struct AbortOnPanic;
impl Drop for AbortOnPanic {
fn drop(&mut self) {
abort!();
}
}
let guard = AbortOnPanic;
// Run task
std::mem::forget(AbortOnPanic);
```
---
## Changelog
Changed: `bevy_tasks::TaskPool`'s threads will no longer terminate permanently when a task scheduled onto them panics.
Changed: `bevy_tasks::Task` and`bevy_tasks::Scope` will propagate panics in the spawned tasks/scopes to the parent thread.
This reverts commit 53d387f340.
# Objective
Reverts #6448. This didn't have the intended effect: we're now getting bevy::prelude shown in the docs again.
Co-authored-by: Alejandro Pascual <alejandro.pascual.pozo@gmail.com>
# Objective
- Right now re-exports are completely hidden in prelude docs.
- Fixes#6433
## Solution
- We could show the re-exports without inlining their documentation.
# Objective
- Time have `Reflect`, but doesn't have `FromReflect`.
## Solution
- Add it for `Timer`, `Stopwatch` and `TimerMode`.
---
## Changelog
### Added
* `FromReflect` derive for `Timer`, `Stopwatch` and `TimerMode`.
# Objective
- Some tests are very flaky on a m1
- m1 currently have a 41 ns precision
## Solution
- Do not run tests that compare a `Duration` or a `f64` on a m1 (and m2)
