Commit graph

83 commits

Author SHA1 Message Date
IcyLeave6109
de7ff295e1
Make bevy_time optionally depend on bevy_reflect (#13263)
# Objective

Fixes #13246.
2024-05-12 23:19:07 +00:00
targrub
8316166622
Fix uses of "it's" vs "its". (#13033)
Grammar changes only.
2024-04-19 18:17:31 +00:00
James Liu
ae9775c83b
Optimize Event Updates (#12936)
# Objective
Improve performance scalability when adding new event types to a Bevy
app. Currently, just using Bevy in the default configuration, all apps
spend upwards of 100+us in the `First` schedule, every app tick,
evaluating if it should update events or not, even if events are not
being used for that particular frame, and this scales with the number of
Events registered in the app.

## Solution
As `Events::update` is guaranteed `O(1)` by just checking if a
resource's value, swapping two Vecs, and then clearing one of them, the
actual cost of running `event_update_system` is *very* cheap. The
overhead of doing system dependency injection, task scheduling ,and the
multithreaded executor outweighs the cost of running the system by a
large margin.

Create an `EventRegistry` resource that keeps a number of function
pointers that update each event. Replace the per-event type
`event_update_system` with a singular exclusive system uses the
`EventRegistry` to update all events instead. Update `SubApp::add_event`
to use `EventRegistry` instead.

## Performance
This speeds reduces the cost of the `First` schedule in both many_foxes
and many_cubes by over 80%. Note this is with system spans on. The
majority of this is now context-switching costs from launching
`time_system`, which should be mostly eliminated with #12869.

![image](https://github.com/bevyengine/bevy/assets/3137680/037624be-21a2-4dc2-a42f-9d0bfa3e9b4a)

The actual `event_update_system` is usually *very* short, using only a
few microseconds on average.

![image](https://github.com/bevyengine/bevy/assets/3137680/01ff1689-3595-49b6-8f09-5c44bcf903e8)

---

## Changelog
TODO

## Migration Guide
TODO

---------

Co-authored-by: Josh Matthews <josh@joshmatthews.net>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2024-04-13 14:11:28 +00:00
BD103
84363f2fab
Remove redundant imports (#12817)
# Objective

- There are several redundant imports in the tests and examples that are
not caught by CI because additional flags need to be passed.

## Solution

- Run `cargo check --workspace --tests` and `cargo check --workspace
--examples`, then fix all warnings.
- Add `test-check` to CI, which will be run in the check-compiles job.
This should catch future warnings for tests. Examples are already
checked, but I'm not yet sure why they weren't caught.

## Discussion

- Should the `--tests` and `--examples` flags be added to CI, so this is
caught in the future?
- If so, #12818 will need to be merged first. It was also a warning
raised by checking the examples, but I chose to split off into a
separate PR.

---------

Co-authored-by: François Mockers <francois.mockers@vleue.com>
2024-04-01 19:59:08 +00:00
James Liu
56bcbb0975
Forbid unsafe in most crates in the engine (#12684)
# Objective
Resolves #3824. `unsafe` code should be the exception, not the norm in
Rust. It's obviously needed for various use cases as it's interfacing
with platforms and essentially running the borrow checker at runtime in
the ECS, but the touted benefits of Bevy is that we are able to heavily
leverage Rust's safety, and we should be holding ourselves accountable
to that by minimizing our unsafe footprint.

## Solution
Deny `unsafe_code` workspace wide. Add explicit exceptions for the
following crates, and forbid it in almost all of the others.

* bevy_ecs - Obvious given how much unsafe is needed to achieve
performant results
* bevy_ptr - Works with raw pointers, even more low level than bevy_ecs.
 * bevy_render - due to needing to integrate with wgpu
 * bevy_window - due to needing to integrate with raw_window_handle
* bevy_utils - Several unsafe utilities used by bevy_ecs. Ideally moved
into bevy_ecs instead of made publicly usable.
 * bevy_reflect - Required for the unsafe type casting it's doing.
 * bevy_transform - for the parallel transform propagation
 * bevy_gizmos  - For the SystemParam impls it has.
* bevy_assets - To support reflection. Might not be required, not 100%
sure yet.
* bevy_mikktspace - due to being a conversion from a C library. Pending
safe rewrite.
* bevy_dynamic_plugin - Inherently unsafe due to the dynamic loading
nature.

Several uses of unsafe were rewritten, as they did not need to be using
them:

* bevy_text - a case of `Option::unchecked` could be rewritten as a
normal for loop and match instead of an iterator.
* bevy_color - the Pod/Zeroable implementations were replaceable with
bytemuck's derive macros.
2024-03-27 03:30:08 +00:00
mamekoro
cb9789bc35
Remove unnecessary executable flags from Rust source files (#12707)
# Objective
I found that some .rs files are unnecessarily executable.

Rust source files may start with a shebang-like statement `#!`, so let's
make sure they are not executable just in case.

Here is the result of the `find` commend that lists executable .rs files
as of main branch `86bd648`.
```console
$ find -name \*.rs -type f -executable
./crates/bevy_gizmos/src/lib.rs
./crates/bevy_tasks/src/lib.rs
./crates/bevy_time/src/lib.rs
./crates/bevy_transform/src/lib.rs
./src/lib.rs
```

It appears that the permissions of those files were originally 644, but
were unexpectedly changed to 755 by commit
52e3f2007b.

## Solution
Make them not executable by using this command;
`find -name \*.rs -type f -executable -exec chmod --verbose a-x -- {}
\+`
2024-03-25 20:03:55 +00:00
James Liu
f096ad4155
Set the logo and favicon for all of Bevy's published crates (#12696)
# Objective
Currently the built docs only shows the logo and favicon for the top
level `bevy` crate. This makes views like
https://docs.rs/bevy_ecs/latest/bevy_ecs/ look potentially unrelated to
the project at first glance.

## Solution
Reproduce the docs attributes for every crate that Bevy publishes.

Ideally this would be done with some workspace level Cargo.toml control,
but AFAICT, such support does not exist.
2024-03-25 18:52:50 +00:00
Al M
52e3f2007b
Add "all-features = true" to docs.rs metadata for most crates (#12366)
# Objective

Fix missing `TextBundle` (and many others) which are present in the main
crate as default features but optional in the sub-crate. See:

- https://docs.rs/bevy/0.13.0/bevy/ui/node_bundles/index.html
- https://docs.rs/bevy_ui/0.13.0/bevy_ui/node_bundles/index.html

~~There are probably other instances in other crates that I could track
down, but maybe "all-features = true" should be used by default in all
sub-crates? Not sure.~~ (There were many.) I only noticed this because
rust-analyzer's "open docs" features takes me to the sub-crate, not the
main one.

## Solution

Add "all-features = true" to docs.rs metadata for crates that use
features.

## Changelog

### Changed

- Unified features documented on docs.rs between main crate and
sub-crates
2024-03-08 20:03:09 +00:00
François
71486393ed
move ci testing to dev_tools (#12371)
# Objective

- Fix #12356
- better isolation of ci testing tools in dev tools instead of being in
various crates

## Solution

- Move the parts doing the work of ci testing to the dev tools
2024-03-07 22:38:21 +00:00
Mateusz Wachowiak
6533170e94
Add bevy_dev_tools crate (#11341)
# Objective

- Resolves #11309

## Solution

- Add `bevy_dev_tools` crate as a default feature.
- Add `DevToolsPlugin` and add it to an app if the `bevy_dev_tools`
feature is enabled.

`bevy_dev_tools` is reserved by @alice-i-cecile, should we wait until it
gets transferred to cart before merging?

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: BD103 <59022059+BD103@users.noreply.github.com>
2024-03-06 20:33:05 +00:00
James Liu
9e5db9abc7
Clean up type registrations (#12314)
# Objective
Fix #12304. Remove unnecessary type registrations thanks to #4154.

## Solution
Conservatively remove type registrations. Keeping the top level
components, resources, and events, but dropping everything else that is
a type of a member of those types.
2024-03-06 16:05:53 +00:00
Tristan Guichaoua
694c06f3d0
Inverse missing_docs logic (#11676)
# Objective

Currently the `missing_docs` lint is allowed-by-default and enabled at
crate level when their documentations is complete (see #3492).
This PR proposes to inverse this logic by making `missing_docs`
warn-by-default and mark crates with imcomplete docs allowed.

## Solution

Makes `missing_docs` warn at workspace level and allowed at crate level
when the docs is imcomplete.
2024-02-03 21:40:55 +00:00
Doug Roeper
c859eacdc8
Fix bug where events are not being dropped (#11528)
# Objective

Fix an issue where events are not being dropped after being read. I
believe #10077 introduced this issue. The code currently works as
follows:

1. `EventUpdateSignal` is **shared for all event types**
2. During the fixed update phase, `EventUpdateSignal` is set to true
3. `event_update_system`, **unique per event type**, runs to update
Events<T>
4. `event_update_system` reads value of `EventUpdateSignal` to check if
it should update, and then **resets** the value to false

If there are multiple event types, the first `event_update_system` run
will reset the shared `EventUpdateSignal` signal, preventing other
events from being cleared.

## Solution

I've updated the code to have separate signals per event type and added
a shared signal to notify all systems that the time plugin is installed.

## Changelog

- Fixed bug where events were not being dropped
2024-02-02 21:14:54 +00:00
Ixentus
5c6b7d5883
Add paused run condition (#11313)
# Objective

- It is common to run a system only when the clock is paused or not
paused, but this run condition doesn't exist.

## Solution

- Add the "paused" run condition.

---

## Changelog

- Systems can now be scheduled to run only if the clock is paused or not
using `.run_if(paused())` or `.run_if(not(paused()))`.

---------

Co-authored-by: radiish <cb.setho@gmail.com>
2024-01-12 22:18:57 +00:00
TimJentzsch
cf3105a0db
Add run conditions for executing a system after a delay (#11095)
# Objective

I want to run a system once after a given delay.

- First, I tried using the `on_timer` run condition, but it uses a
repeating timer, causing the system to run multiple times.
- Next, I tried combining the `on_timer` with the `run_once` run
condition. However, this causes the timer to *tick* only once, so the
system is never executed.

## Solution

- ~~Replace `on_timer` by `on_time_interval` and `on_real_timer` by
`on_real_time_interval` to clarify the meaning (the old ones are
deprecated to avoid a breaking change).~~ (Reverted according to
feedback)
- Add `once_after_delay` and `once_after_real_delay` to run the system
exactly once after the delay, using `TimerMode::Once`.
- Add `repeating_after_delay` and `repeating_after_real_delay` to run
the system indefinitely after the delay, using `Timer::finished` instead
of `Timer::just_finished`.

---

## Changelog

### Added

- `once_after_delay` and `once_after_real_delay` run conditions to run
the system exactly once after the delay, using `TimerMode::Once`.
- `repeating_after_delay` and `repeating_after_real_delay` run
conditions to run the system indefinitely after the delay, using
`Timer::finished` instead of `Timer::just_finished`.
2024-01-08 23:52:16 +00:00
Doonv
189ceaf0d3
Replace or document ignored doctests (#11040)
# Objective

There are a lot of doctests that are `ignore`d for no documented reason.
And that should be fixed.

## Solution

I searched the bevy repo with the regex ` ```[a-z,]*ignore ` in order to
find all `ignore`d doctests. For each one of the `ignore`d doctests, I
did the following steps:
1. Attempt to remove the `ignored` attribute while still passing the
test. I did this by adding hidden dummy structs and imports.
2. If step 1 doesn't work, attempt to replace the `ignored` attribute
with the `no_run` attribute while still passing the test.
3. If step 2 doesn't work, keep the `ignored` attribute but add
documentation for why the `ignored` attribute was added.

---------

Co-authored-by: François <mockersf@gmail.com>
2024-01-01 16:50:56 +00:00
Thierry Berger
ced216f59a
Update winit dependency to 0.29 (#10702)
# Objective

- Update winit dependency to 0.29

## Changelog

### KeyCode changes

- Removed `ScanCode`, as it was [replaced by
KeyCode](https://github.com/rust-windowing/winit/blob/master/CHANGELOG.md#0292).
- `ReceivedCharacter.char` is now a `SmolStr`, [relevant
doc](https://docs.rs/winit/latest/winit/event/struct.KeyEvent.html#structfield.text).
- Changed most `KeyCode` values, and added more.

KeyCode has changed meaning. With this PR, it refers to physical
position on keyboard rather than the printed letter on keyboard keys.

In practice this means:
- On QWERTY keyboard layouts, nothing changes
- On any other keyboard layout, `KeyCode` no longer reflects the label
on key.
- This is "good". In bevy 0.12, when you used WASD for movement, users
with non-QWERTY keyboards couldn't play your game! This was especially
bad for non-latin keyboards. Now, WASD represents the physical keys. A
French player will press the ZQSD keys, which are near each other,
Kyrgyz players will use "Цфыв".
- This is "bad" as well. You can't know in advance what the label of the
key for input is. Your UI says "press WASD to move", even if in reality,
they should be pressing "ZQSD" or "Цфыв". You also no longer can use
`KeyCode` for text inputs. In any case, it was a pretty bad API for text
input. You should use `ReceivedCharacter` now instead.

### Other changes
- Use `web-time` rather than `instant` crate.
(https://github.com/rust-windowing/winit/pull/2836)
- winit did split `run_return` in `run_onDemand` and `pump_events`, I
did the same change in bevy_winit and used `pump_events`.
- Removed `return_from_run` from `WinitSettings` as `winit::run` now
returns on supported platforms.
- I left the example "return_after_run" as I think it's still useful.
- This winit change is done partly to allow to create a new window after
quitting all windows: https://github.com/emilk/egui/issues/1918 ; this
PR doesn't address.
- added `width` and `height` properties in the `canvas` from wasm
example
(https://github.com/bevyengine/bevy/pull/10702#discussion_r1420567168)

## Known regressions (important follow ups?)
- Provide an API for reacting when a specific key from current layout
was released.
- possible solutions: use winit::Key from winit::KeyEvent ; mapping
between KeyCode and Key ; or .
- We don't receive characters through alt+numpad (e.g. alt + 151 = "ù")
anymore ; reproduced on winit example "ime". maybe related to
https://github.com/rust-windowing/winit/issues/2945
- (windows) Window content doesn't refresh at all when resizing. By
reading https://github.com/rust-windowing/winit/issues/2900 ; I suspect
we should just fire a `window.request_redraw();` from `AboutToWait`, and
handle actual redrawing within `RedrawRequested`. I'm not sure how to
move all that code so I'd appreciate it to be a follow up.
- (windows) unreleased winit fix for using set_control_flow in
AboutToWait https://github.com/rust-windowing/winit/issues/3215 ; ⚠️ I'm
not sure what the implications are, but that feels bad 🤔

## Follow up 

I'd like to avoid bloating this PR, here are a few follow up tasks
worthy of a separate PR, or new issue to track them once this PR is
closed, as they would either complicate reviews, or at risk of being
controversial:
- remove CanvasParentResizePlugin
(https://github.com/bevyengine/bevy/pull/10702#discussion_r1417068856)
- avoid mentionning explicitly winit in docs from bevy_window ?
- NamedKey integration on bevy_input:
https://github.com/rust-windowing/winit/pull/3143 introduced a new
NamedKey variant. I implemented it only on the converters but we'd
benefit making the same changes to bevy_input.
- Add more info in KeyboardInput
https://github.com/bevyengine/bevy/pull/10702#pullrequestreview-1748336313
- https://github.com/bevyengine/bevy/pull/9905 added a workaround on a
bug allegedly fixed by winit 0.29. We should check if it's still
necessary.
- update to raw_window_handle 0.6
  - blocked by wgpu
- Rename `KeyCode` to `PhysicalKeyCode`
https://github.com/bevyengine/bevy/pull/10702#discussion_r1404595015
- remove `instant` dependency, [replaced
by](https://github.com/rust-windowing/winit/pull/2836) `web_time`), we'd
need to update to :
  - fastrand >= 2.0
- [`async-executor`](https://github.com/smol-rs/async-executor) >= 1.7
    - [`futures-lite`](https://github.com/smol-rs/futures-lite) >= 2.0
- Verify license, see
[discussion](https://github.com/bevyengine/bevy/pull/8745#discussion_r1402439800)
  - we might be missing a short notice or description of changes made
- Consider using https://github.com/rust-windowing/cursor-icon directly
rather than vendoring it in bevy.
- investigate [this
unwrap](https://github.com/bevyengine/bevy/pull/8745#discussion_r1387044986)
(`winit_window.canvas().unwrap();`)
- Use more good things about winit's update
- https://github.com/bevyengine/bevy/pull/10689#issuecomment-1823560428
## Migration Guide

This PR should have one.
2023-12-21 07:40:47 +00:00
Aceeri
fe28e0ec32
Add First/Pre/Post/Last schedules to the Fixed timestep (#10977)
Fixes https://github.com/bevyengine/bevy/issues/10974

# Objective
Duplicate the ordering logic of the `Main` schedule into the `FixedMain`
schedule.

---

## Changelog
- `FixedUpdate` is no longer the main schedule ran in
`RunFixedUpdateLoop`, `FixedMain` has replaced this and has a similar
structure to `Main`.

## Migration Guide
- Usage of `RunFixedUpdateLoop` should be renamed to `RunFixedMainLoop`.
2023-12-14 04:35:40 +00:00
Cameron
53919c3e70
Wait until FixedUpdate can see events before dropping them (#10077)
## 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>
2023-11-26 23:04:41 +00:00
Ame
951c9bb1a2
Add [lints] table, fix adding #![allow(clippy::type_complexity)] everywhere (#10011)
# 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>
2023-11-18 20:58:48 +00:00
NiseVoid
1d3ae677df
Add discard_overstep function to Time<Fixed> (#10453)
# 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>
2023-11-18 00:50:26 +00:00
mamekoro
18d001d27c
Rename Timer::{percent,percent_left} to Timer::{fraction,fraction_remaining} (#10442)
# 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()`
2023-11-13 14:59:42 +00:00
mamekoro
54b7cabc7b
Rename Time::<Fixed>::overstep_percentage() and Time::<Fixed>::overstep_percentage_f64() (#10448)
# 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()`
2023-11-13 14:36:46 +00:00
Jesus Bracho
32a5c7db35
docs: use read instead of deprecated iter (#10376)
https://docs.rs/bevy/latest/bevy/ecs/event/struct.EventReader.html#method.iter

# Objective

- Remove doc example using deprecated `EventReader.iter` method

## Solution

- Update docs to use `read` instead of `iter`
2023-11-05 02:03:42 +00:00
SecretPocketCat
b1cc7ad72f
add on_real_time_timer run condition (#10179)
# Objective

Fixes #10177 .

## Solution

Added a new run condition and tweaked the docs for `on_timer`.

## Changelog

### Added 
 - `on_real_time_timer` run condition
2023-10-20 12:58:37 +00:00
Carter Anderson
a042924a6e
Time: demote delta time clamping warning to debug (#10145)
# 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
2023-10-16 19:18:39 +00:00
Nuutti Kotivuori
3d79dc4cdc
Unify FixedTime and Time while fixing several problems (#8964)
# 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>
2023-10-16 01:57:55 +00:00
Mike
1d7577fc42
ignore time channel error (#9981)
# 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.
2023-10-01 07:55:17 +00:00
cyqsimon
14db5b38dc
Clarify behaviour of Timer::finished() for repeating timers (#9939)
# 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.
2023-09-29 21:57:01 +00:00
Bruce Mitchener
5e91e5f3ce
Improve doc formatting. (#9840)
# Objective

- Identifiers in docs should be marked up with backticks.

## Solution

- Mark up more identifiers in the docs with backticks.
2023-09-18 19:43:56 +00:00
Joseph
8eb6ccdd87
Remove useless single tuples and trailing commas (#9720)
# Objective

Title
2023-09-08 21:46:54 +00:00
Mike
33fdc5f5db
Move schedule name into Schedule (#9600)
# 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);
```
2023-08-28 20:44:48 +00:00
Joseph
f99dcadf8a
Add missing documentation to bevy_time (#9428)
# Objective

* Add documentation to undocumented items in `bevy_time`.
* Add a warning for undocumented items.

---------

Co-authored-by: Sélène Amanita <134181069+Selene-Amanita@users.noreply.github.com>
2023-08-15 21:48:37 +00:00
Gino Valente
aeeb20ec4c
bevy_reflect: FromReflect Ergonomics Implementation (#6056)
# 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(&registry);
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(&registry);
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(&registry);
  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(&registry);
  
  // NEW
let reflect_deserializer =
UntypedReflectDeserializer::new_dynamic(&registry);
  ```

</details>

---------

Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
张林伟
a9ca40506e
Hide naga info logs & Derive PartialEq on Timer and Stopwatch (#8664)
# Objective

- Fixes https://github.com/bevyengine/bevy/issues/8662
- Fixes https://github.com/bevyengine/bevy/issues/8663

---------

Co-authored-by: Andres O. Vela <andresovela@users.noreply.github.com>
2023-05-24 15:16:15 +00:00
François
8070c29c21
Take example screenshots in CI (#8488)
# 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.
2023-05-01 18:00:01 +00:00
Rostyslav Toch
e2531b2273
Fix timer with zero duration (#8467)
# 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.
2023-04-24 14:32:42 +00:00
JoJoJet
0174d632a5
Add a scope API for world schedules (#8387)
# 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>
2023-04-16 05:09:33 +00:00
JoJoJet
1074a41b87
Fix docs for fixed timestep (#8363)
# Objective

The docs for `FixedTime::expend` are unfinished.
2023-04-14 19:41:31 +00:00
JoJoJet
3ead10a3e0
Suppress the clippy::type_complexity lint (#8313)
# 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.
2023-04-06 21:27:36 +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
Bruce Reif (Buswolley)
7c4a0eb768
add Clone to common conditions (#8060) 2023-03-13 19:38:04 +00:00
jabu
98cf0d2d2d Add timer-based common run conditions (on_timer and on_fixed_timer) (#7866)
# 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
2023-03-02 12:53:54 +00:00
Jakob Hellermann
d1a1f90902 fix Time::pause docs (missing "not") (#7807)
# Objective

Time pausing does *not* affect `raw_*`.

## Solution

- add missing word "not"
2023-02-24 12:55:43 +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
Rob Parrett
b39f83640f Fix some typos (#7763)
# Objective

Stumbled on a typo and went on a typo hunt.

## Solution

Fix em
2023-02-20 22:56:57 +00:00
Sludge
104c74c3bc Allow relative speed of -0.0 (#7740)
# 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.
2023-02-18 22:43:08 +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