# Objective
- Bevy should not have any "internal" execution order ambiguities. These clutter the output of user-facing error reporting, and can result in nasty, nondetermistic, very difficult to solve bugs.
- Verifying this currently involves repeated non-trivial manual work.
## Solution
- [x] add an example to quickly check this
- ~~[ ] ensure that this example panics if there are any unresolved ambiguities~~
- ~~[ ] run the example in CI 😈~~
There's one tricky ambiguity left, between UI and animation. I don't have the tools to fix this without system set configuration, so the remaining work is going to be left to #7267 or another PR after that.
```
2023-01-27T18:38:42.989405Z INFO bevy_ecs::schedule::ambiguity_detection: Execution order ambiguities detected, you might want to add an explicit dependency relation between some of these systems:
* Parallel systems:
-- "bevy_animation::animation_player" and "bevy_ui::flex::flex_node_system"
conflicts: ["bevy_transform::components::transform::Transform"]
```
## Changelog
Resolved internal execution order ambiguities for:
1. Transform propagation (ignored, we need smarter filter checking).
2. Gamepad processing (fixed).
3. bevy_winit's window handling (fixed).
4. Cascaded shadow maps and perspectives (fixed).
Also fixed a desynchronized state bug that could occur when the `Window` component is removed and then added to the same entity in a single frame.
# Objective
Fixes#3184. Fixes#6640. Fixes#4798. Using `Query::par_for_each(_mut)` currently requires a `batch_size` parameter, which affects how it chunks up large archetypes and tables into smaller chunks to run in parallel. Tuning this value is difficult, as the performance characteristics entirely depends on the state of the `World` it's being run on. Typically, users will just use a flat constant and just tune it by hand until it performs well in some benchmarks. However, this is both error prone and risks overfitting the tuning on that benchmark.
This PR proposes a naive automatic batch-size computation based on the current state of the `World`.
## Background
`Query::par_for_each(_mut)` schedules a new Task for every archetype or table that it matches. Archetypes/tables larger than the batch size are chunked into smaller tasks. Assuming every entity matched by the query has an identical workload, this makes the worst case scenario involve using a batch size equal to the size of the largest matched archetype or table. Conversely, a batch size of `max {archetype, table} size / thread count * COUNT_PER_THREAD` is likely the sweetspot where the overhead of scheduling tasks is minimized, at least not without grouping small archetypes/tables together.
There is also likely a strict minimum batch size below which the overhead of scheduling these tasks is heavier than running the entire thing single-threaded.
## Solution
- [x] Remove the `batch_size` from `Query(State)::par_for_each` and friends.
- [x] Add a check to compute `batch_size = max {archeytpe/table} size / thread count * COUNT_PER_THREAD`
- [x] ~~Panic if thread count is 0.~~ Defer to `for_each` if the thread count is 1 or less.
- [x] Early return if there is no matched table/archetype.
- [x] Add override option for users have queries that strongly violate the initial assumption that all iterated entities have an equal workload.
---
## Changelog
Changed: `Query::par_for_each(_mut)` has been changed to `Query::par_iter(_mut)` and will now automatically try to produce a batch size for callers based on the current `World` state.
## Migration Guide
The `batch_size` parameter for `Query(State)::par_for_each(_mut)` has been removed. These calls will automatically compute a batch size for you. Remove these parameters from all calls to these functions.
Before:
```rust
fn parallel_system(query: Query<&MyComponent>) {
query.par_for_each(32, |comp| {
...
});
}
```
After:
```rust
fn parallel_system(query: Query<&MyComponent>) {
query.par_iter().for_each(|comp| {
...
});
}
```
Co-authored-by: Arnav Choubey <56453634+x-52@users.noreply.github.com>
Co-authored-by: Robert Swain <robert.swain@gmail.com>
Co-authored-by: François <mockersf@gmail.com>
Co-authored-by: Corey Farwell <coreyf@rwell.org>
Co-authored-by: Aevyrie <aevyrie@gmail.com>
# Objective
Fix#4647. If any child is changed, or even reordered, `Changed<Children>` is true, which causes transform propagation to propagate changes to all siblings of a changed child, even if they don't need to be.
## Solution
As `Parent` and `Children` are updated in tandem in hierarchy commands after #4800. `Changed<Parent>` is true on the child when `Changed<Children>` is true on the parent. However, unlike checking children, checking `Changed<Parent>` is only localized to the current entity and will not force propagation to the siblings.
Also took the opportunity to change propagation to use `Query::iter_many` instead of repeated `Query::get` calls. Should cut a bit of the overhead out of propagation. This means we won't panic when there isn't a `Parent` on the child, just skip over it.
The tests from #4608 still pass, so the change detection here still works just fine under this approach.
# Objective
It is often necessary to update an entity's parent
while keeping its GlobalTransform static. Currently
it is cumbersome and error-prone (two questions in
the discord `#help` channel in the past week)
- Part 2, resolves#5475
- Builds on: #7020.
## Solution
- Added the `BuildChildrenTransformExt` trait, it is part
of `bevy::prelude` and adds the following methods to `EntityCommands`:
- `set_parent_in_place`: Change the parent of an entity and
update its `Transform` in order to preserve its `GlobalTransform` after the parent change
- `remove_parent_in_place`: Remove an entity from a hierarchy,
while preserving its `GlobalTransform`.
---
## Changelog
- Added the `BuildChildrenTransformExt` trait, it is part
of `bevy::prelude` and adds the following methods to `EntityCommands`:
- `set_parent_in_place`: Change the parent of an entity and
update its `Transform` in order to preserve its `GlobalTransform` after the parent change
- `remove_parent_in_place`: Remove an entity from a hierarchy,
while preserving its `GlobalTransform`.
Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
# Objective
It is possible to manually update `GlobalTransform`.
The engine actually assumes this is not possible.
For example, `propagate_transform` does not update children
of an `Entity` which **`GlobalTransform`** changed,
leading to unexpected behaviors.
A `GlobalTransform` set by the user may also be blindly
overwritten by the propagation system.
## Solution
- Remove `translation_mut`
- Explain to users that they shouldn't manually update the `GlobalTransform`
- Remove `global_vs_local.rs` example, since it misleads users
in believing that it is a valid use-case to manually update the
`GlobalTransform`
---
## Changelog
- Remove `GlobalTransform::translation_mut`
## Migration Guide
`GlobalTransform::translation_mut` has been removed without alternative,
if you were relying on this, update the `Transform` instead. If the given entity
had children or parent, you may need to remove its parent to make its transform
independent (in which case the new `Commands::set_parent_in_place` and
`Commands::remove_parent_in_place` may be of interest)
Bevy may add in the future a way to toggle transform propagation on
an entity basis.
# Objective
It is often necessary to update an entity's parent while keeping its GlobalTransform static. Currently it is cumbersome and error-prone (two questions in the discord `#help` channel in the past week)
- Part 1 of #5475
- Part 2: #7024.
## Solution
- Add a `reparented_to` method to `GlobalTransform`
---
## Changelog
- Add a `reparented_to` method to `GlobalTransform`
# Objective
Fixes#4697. Hierarchical propagation of properties, currently only Transform -> GlobalTransform, can be a very expensive operation. Transform propagation is a strict dependency for anything positioned in world-space. In large worlds, this can take quite a bit of time, so limiting it to a single thread can result in poor CPU utilization as it bottlenecks the rest of the frame's systems.
## Solution
- Move transforms without a parent or a child (free-floating (Global)Transform) entities into a separate parallel system.
- Chunk the hierarchy based on the root entities and process it in parallel with `Query::par_for_each_mut`.
- Utilize the hierarchy's specific properties introduced in #4717 to allow for safe use of `Query::get_unchecked` on multiple threads. Assuming each child is unique in the hierarchy, it is impossible to have an aliased `&mut GlobalTransform` so long as we verify that the parent for a child is the same one propagated from.
---
## Changelog
Removed: `transform_propagate_system` is no longer `pub`.
Add a method to rotate a transform to point towards a direction.
Also updated the docs to link to `forward` and `up` instead of mentioning local negative `Z` and local `Y`.
Unfortunately, links to methods don't work in rust-analyzer :(
Co-authored-by: Devil Ira <justthecooldude@gmail.com>
# Objective
Fix#6453.
## Solution
Use the solution mentioned in the issue by catching the unwind and dropping the error. Wrap the `executor.try_tick` calls with `std::catch::unwind`.
Ideally this would be moved outside of the hot loop, but the mut ref to the `spawned` future is not `UnwindSafe`.
This PR only addresses the bug, we can address the perf issues (should there be any) later.
# 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
Fixes#6378
`bevy_transform` is missing a feature corresponding to the `serialize` feature on the `bevy` crate.
## Solution
Adds a `serialize` feature to `bevy_transform`.
Derives `serde::Serialize` and `Deserialize` when feature is enabled.
Bevy's coordinate system is right-handed Y up, so +Z points towards my nose and I'm looking in the -Z direction. Therefore, `Transform::looking_at/look_at` must be pointing towards -Z. Or am I wrong here?
This is a holdover from back when `Transform` was backed by a private `Mat4` two years ago.
Not particularly useful anymore :)
## Migration Guide
`Transform::apply_non_uniform_scale` has been removed.
It can be replaced with the following snippet:
```rust
transform.scale *= scale_factor;
```
Co-authored-by: devil-ira <justthecooldude@gmail.com>
The docs ended up quite verbose :v
Also added a missing `#[inline]` to `GlobalTransform::mul_transform`.
I'd say this resolves#5500
# Migration Guide
`Transform::mul_vec3` has been renamed to `transform_point`.
Co-authored-by: devil-ira <justthecooldude@gmail.com>
# Objective
Make `GlobalTransform` constructible from scripts, in the same vein as #6187.
## Solution
- Use the derive macro to reflect default
---
## Changelog
> This section is optional. If this was a trivial fix, or has no externally-visible impact, you can delete this section.
- `GlobalTransform` now reflects the `Default` trait.
# Objective
- Fix#5285
## Solution
- Put the panicking system in a single threaded stage during the test
- This way only the main thread will panic, which is handled by `cargo test`
# Objective
Now that we can consolidate Bundles and Components under a single insert (thanks to #2975 and #6039), almost 100% of world spawns now look like `world.spawn().insert((Some, Tuple, Here))`. Spawning an entity without any components is an extremely uncommon pattern, so it makes sense to give spawn the "first class" ergonomic api. This consolidated api should be made consistent across all spawn apis (such as World and Commands).
## Solution
All `spawn` apis (`World::spawn`, `Commands:;spawn`, `ChildBuilder::spawn`, and `WorldChildBuilder::spawn`) now accept a bundle as input:
```rust
// before:
commands
.spawn()
.insert((A, B, C));
world
.spawn()
.insert((A, B, C);
// after
commands.spawn((A, B, C));
world.spawn((A, B, C));
```
All existing instances of `spawn_bundle` have been deprecated in favor of the new `spawn` api. A new `spawn_empty` has been added, replacing the old `spawn` api.
By allowing `world.spawn(some_bundle)` to replace `world.spawn().insert(some_bundle)`, this opened the door to removing the initial entity allocation in the "empty" archetype / table done in `spawn()` (and subsequent move to the actual archetype in `.insert(some_bundle)`).
This improves spawn performance by over 10%:
To take this measurement, I added a new `world_spawn` benchmark.
Unfortunately, optimizing `Commands::spawn` is slightly less trivial, as Commands expose the Entity id of spawned entities prior to actually spawning. Doing the optimization would (naively) require assurances that the `spawn(some_bundle)` command is applied before all other commands involving the entity (which would not necessarily be true, if memory serves). Optimizing `Commands::spawn` this way does feel possible, but it will require careful thought (and maybe some additional checks), which deserves its own PR. For now, it has the same performance characteristics of the current `Commands::spawn_bundle` on main.
**Note that 99% of this PR is simple renames and refactors. The only code that needs careful scrutiny is the new `World::spawn()` impl, which is relatively straightforward, but it has some new unsafe code (which re-uses battle tested BundlerSpawner code path).**
---
## Changelog
- All `spawn` apis (`World::spawn`, `Commands:;spawn`, `ChildBuilder::spawn`, and `WorldChildBuilder::spawn`) now accept a bundle as input
- All instances of `spawn_bundle` have been deprecated in favor of the new `spawn` api
- World and Commands now have `spawn_empty()`, which is equivalent to the old `spawn()` behavior.
## Migration Guide
```rust
// Old (0.8):
commands
.spawn()
.insert_bundle((A, B, C));
// New (0.9)
commands.spawn((A, B, C));
// Old (0.8):
commands.spawn_bundle((A, B, C));
// New (0.9)
commands.spawn((A, B, C));
// Old (0.8):
let entity = commands.spawn().id();
// New (0.9)
let entity = commands.spawn_empty().id();
// Old (0.8)
let entity = world.spawn().id();
// New (0.9)
let entity = world.spawn_empty();
```
# Objective
Both components already derives `Reflect` and it would be nice to have `FromReflect` in order to ser/de between those types without relaying on `downcast`, since it can fail between different platforms, like WebAssembly.
## Solution
Derive `FromReflect` for `Transform` and `GlobalTransform`.
I thought if I should also derive `FromReflect` for `GlobalTransform`, since it's a computed component, but there may be some use cases where a `GlobalTransform` is needed to be sent over the wire, so I decided to do it.
# Objective
Take advantage of the "impl Bundle for Component" changes in #2975 / add the follow up changes discussed there.
## Solution
- Change `insert` and `remove` to accept a Bundle instead of a Component (for both Commands and World)
- Deprecate `insert_bundle`, `remove_bundle`, and `remove_bundle_intersection`
- Add `remove_intersection`
---
## Changelog
- Change `insert` and `remove` now accept a Bundle instead of a Component (for both Commands and World)
- `insert_bundle` and `remove_bundle` are deprecated
## Migration Guide
Replace `insert_bundle` with `insert`:
```rust
// Old (0.8)
commands.spawn().insert_bundle(SomeBundle::default());
// New (0.9)
commands.spawn().insert(SomeBundle::default());
```
Replace `remove_bundle` with `remove`:
```rust
// Old (0.8)
commands.entity(some_entity).remove_bundle::<SomeBundle>();
// New (0.9)
commands.entity(some_entity).remove::<SomeBundle>();
```
Replace `remove_bundle_intersection` with `remove_intersection`:
```rust
// Old (0.8)
world.entity_mut(some_entity).remove_bundle_intersection::<SomeBundle>();
// New (0.9)
world.entity_mut(some_entity).remove_intersection::<SomeBundle>();
```
Consider consolidating as many operations as possible to improve ergonomics and cut down on archetype moves:
```rust
// Old (0.8)
commands.spawn()
.insert_bundle(SomeBundle::default())
.insert(SomeComponent);
// New (0.9) - Option 1
commands.spawn().insert((
SomeBundle::default(),
SomeComponent,
))
// New (0.9) - Option 2
commands.spawn_bundle((
SomeBundle::default(),
SomeComponent,
))
```
## Next Steps
Consider changing `spawn` to accept a bundle and deprecate `spawn_bundle`.
# Objective
Working on issue #1934 , with linking examples to the documentation. PR for transform examples.
## Solution
Added to the documentation in bevy_transform transform.rs and global_transform.rs utilizing links from examples.
[X] 3d_rotations.rs linked to rotate in Transform
[X] global_vs_local_translation.rs linked to top of Transform and GlobalTransform documentation
[X] scale.rs linked to scale Struct in Transform
[X] transform.rs linked to top of Transform documentation
[X] translation.rs linked to from_translation in Transform
Co-authored-by: bwhitt7 <103079612+bwhitt7@users.noreply.github.com>
# Objective
A common pitfall since 0.8 is the requirement on `ComputedVisibility`
being present on all ancestors of an entity that itself has
`ComputedVisibility`, without which, the entity becomes invisible.
I myself hit the issue and got very confused, and saw a few people hit
it as well, so it makes sense to provide a hint of what to do when such
a situation is encountered.
- Fixes#5849
- Closes#5616
- Closes#2277
- Closes#5081
## Solution
We now check that all entities with both a `Parent` and a
`ComputedVisibility` component have parents that themselves have a
`ComputedVisibility` component.
Note that the warning is only printed once.
We also add a similar warning to `GlobalTransform`.
This only emits a warning. Because sometimes it could be an intended
behavior.
Alternatives:
- Do nothing and keep repeating to newcomers how to avoid recurring
pitfalls
- Make the transform and visibility propagation tolerant to missing
components (#5616)
- Probably archetype invariants, though the current draft would not
allow detecting that kind of errors
---
## Changelog
- Add a warning when encountering dubious component hierarchy structure
Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
# Objective
Since `identity` is a const fn that takes no arguments it seems logical to make it an associated constant.
This is also more in line with types from glam (eg. `Quat::IDENTITY`).
## Migration Guide
The method `identity()` on `Transform`, `GlobalTransform` and `TransformBundle` has been deprecated.
Use the associated constant `IDENTITY` instead.
Co-authored-by: devil-ira <justthecooldude@gmail.com>
# Objective
- Help user when they need to add both a `TransformBundle` and a `VisibilityBundle`
## Solution
- Add a `SpatialBundle` adding all components
# Objective
- Add capability to use `Affine3A`s for some `GlobalTransform`s. This allows affine transformations that are not possible using a single `Transform` such as shear and non-uniform scaling along an arbitrary axis.
- Related to #1755 and #2026
## Solution
- `GlobalTransform` becomes an enum wrapping either a `Transform` or an `Affine3A`.
- The API of `GlobalTransform` is minimized to avoid inefficiency, and to make it clear that operations should be performed using the underlying data types.
- using `GlobalTransform::Affine3A` disables transform propagation, because the main use is for cases that `Transform`s cannot support.
---
## Changelog
- `GlobalTransform`s can optionally support any affine transformation using an `Affine3A`.
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
Someone noted that the `rotate_around` method did not give the results they expected: [discord thread](https://discord.com/channels/691052431525675048/996497295325544479)
I tested `rotate_around` and their workaround and it seems like it was indeed incorrect.
Here is a scene with some cubes at different angles all being rotated around the center on the Y axis.
https://user-images.githubusercontent.com/29694403/178598432-407d7e80-1caf-4b17-b69b-66d9156c81e1.mp4
Interestingly, the middle cube rotates as you might expect. This threw me for a bit of a loop before I added the other cubes to the test haha.
Here is the same scene with the order multiplication of the quaternions flipped in `rotate_around`.
https://user-images.githubusercontent.com/29694403/178598446-a98026f3-524c-448b-8437-4d0d3175c6ca.mp4
That looks better :)
## Changelog
* Fixed `rotate_around` rotating the wrong way around
* Added `translate_around`. - Split out the translation code from `rotate_around`.
* Simplified/optimized `rotate_local_*` methods. - Yep, That works somehow.
<sup>Quaternions sure are wacky. Do not ask me how this works exactly, haha.</sup>
Co-authored-by: devil-ira <justthecooldude@gmail.com>
# Objective
- Added a bunch of backticks to things that should have them, like equations, abstract variable names,
- Changed all small x, y, and z to capitals X, Y, Z.
This might be more annoying than helpful; Feel free to refuse this PR.
Remove unnecessary calls to `iter()`/`iter_mut()`.
Mainly updates the use of queries in our code, docs, and examples.
```rust
// From
for _ in list.iter() {
for _ in list.iter_mut() {
// To
for _ in &list {
for _ in &mut list {
```
We already enable the pedantic lint [clippy::explicit_iter_loop](https://rust-lang.github.io/rust-clippy/stable/) inside of Bevy. However, this only warns for a few known types from the standard library.
## Note for reviewers
As you can see the additions and deletions are exactly equal.
Maybe give it a quick skim to check I didn't sneak in a crypto miner, but you don't have to torture yourself by reading every line.
I already experienced enough pain making this PR :)
Co-authored-by: devil-ira <justthecooldude@gmail.com>
## Objective
Implement absolute minimum viable product for the changes proposed in bevyengine/rfcs#53.
## Solution
- Remove public mutative access to `Parent` (Children is already publicly read-only). This includes public construction methods like `Copy`, `Clone`, and `Default`.
- Remove `PreviousParent`
- Remove `parent_update_system`
- Update all hierarchy related commands to immediately update both `Parent` and `Children` references.
## Remaining TODOs
- [ ] Update documentation for both `Parent` and `Children`. Discourage using `EntityCommands::remove`
- [x] Add `HierarchyEvent` to notify listeners of hierarchy updates. This is meant to replace listening on `PreviousParent`
## Followup
- These changes should be best moved to the hooks mentioned in #3742.
- Backing storage for both might be best moved to indexes mentioned in the same relations.
Removed `const_vec2`/`const_vec3`
and replaced with equivalent `.from_array`.
# Objective
Fixes#5112
## Solution
- `encase` needs to update to `glam` as well. See teoxoy/encase#4 on progress on that.
- `hexasphere` also needs to be updated, see OptimisticPeach/hexasphere#12.
# Objective
Users often ask for help with rotations as they struggle with `Quat`s.
`Quat` is rather complex and has a ton of verbose methods.
## Solution
Add rotation helper methods to `Transform`.
Co-authored-by: devil-ira <justthecooldude@gmail.com>
# Objective
- Fixes#4996
## Solution
- Panicking on the global task pool is probably bad. This changes the panicking test to use a single threaded stage to run the test instead.
- I checked the other #[should_panic]
- I also added explicit ordering between the transform propagate system and the parent update system. The ambiguous ordering didn't seem to be causing problems, but the tests are probably more correct this way. The plugins that add these systems have an explicit ordering. I can remove this if necessary.
## Note
I don't have a 100% mental model of why panicking is causing intermittent failures. It probably has to do with a task for one of the other tests landing on the panicking thread when it actually panics. Why this causes a problem I'm not sure, but this PR seems to fix things.
## Open questions
- there are some other #[should_panic] tests that run on the task pool in stage.rs. I don't think we restart panicked threads, so this might be killing most of the threads on the pool. But since they're not causing test failures, we should probably decide what to do about that separately. The solution in this PR won't work since those tests are explicitly testing parallelism.
# Objective
- Transform propogation could stack overflow when there was a cycle.
- I think https://github.com/bevyengine/bevy/pull/4203 would use all available memory.
## Solution
- Make sure that the child entity's `Parent`s are their parents.
This is also required for when parallelising, although as noted in the comment, the naïve solution would be UB.
(The best way to fix this would probably be an `&mut UnsafeCell<T>` `WorldQuery`, or wrapper type with the same effect)
### Problem
It currently isn't possible to construct the default value of a reflected type. Because of that, it isn't possible to use `add_component` of `ReflectComponent` to add a new component to an entity because you can't know what the initial value should be.
### Solution
1. add `ReflectDefault` type
```rust
#[derive(Clone)]
pub struct ReflectDefault {
default: fn() -> Box<dyn Reflect>,
}
impl ReflectDefault {
pub fn default(&self) -> Box<dyn Reflect> {
(self.default)()
}
}
impl<T: Reflect + Default> FromType<T> for ReflectDefault {
fn from_type() -> Self {
ReflectDefault {
default: || Box::new(T::default()),
}
}
}
```
2. add `#[reflect(Default)]` to all component types that implement `Default` and are user facing (so not `ComputedSize`, `CubemapVisibleEntities` etc.)
This makes it possible to add the default value of a component to an entity without any compile-time information:
```rust
fn main() {
let mut app = App::new();
app.register_type::<Camera>();
let type_registry = app.world.get_resource::<TypeRegistry>().unwrap();
let type_registry = type_registry.read();
let camera_registration = type_registry.get(std::any::TypeId::of::<Camera>()).unwrap();
let reflect_default = camera_registration.data::<ReflectDefault>().unwrap();
let reflect_component = camera_registration
.data::<ReflectComponent>()
.unwrap()
.clone();
let default = reflect_default.default();
drop(type_registry);
let entity = app.world.spawn().id();
reflect_component.add_component(&mut app.world, entity, &*default);
let camera = app.world.entity(entity).get::<Camera>().unwrap();
dbg!(&camera);
}
```
### Open questions
- should we have `ReflectDefault` or `ReflectFromWorld` or both?
Supercedes https://github.com/bevyengine/bevy/pull/3340, and absorbs the test from there.
# Objective
- Fixes#3329
## Solution
- If the `Children` component has changed, we currently do not have a way to know how it has changed.
- Therefore, we must update the hierarchy downwards from that point to be correct.
Co-authored-by: Daniel McNab <36049421+DJMcNab@users.noreply.github.com>
# Objective
- in #3851, a feature for tracing was added to bevy_transform
- usage of that feature was moved to bevy_hierarchy, but the feature was not updated
## Solution
- add the feature to bevy_hierarchy, remove it from bevy_transform
# Objective
- Provide more information when despawning an entity
## Solution
- Add a debug log when despawning an entity
- Add spans to the recursive ways of despawning an entity
```sh
RUST_LOG=debug cargo run --example panic --features trace
# RUST_LOG=debug needed to show debug logs from bevy_ecs
# --features trace needed to have the extra spans
...
DEBUG bevy_app:frame:stage{name=Update}:system_commands{name="panic::despawn_parent"}:command{name="DespawnRecursive" entity=0v0}: bevy_ecs::world: Despawning entity 1v0
DEBUG bevy_app:frame:stage{name=Update}:system_commands{name="panic::despawn_parent"}:command{name="DespawnRecursive" entity=0v0}: bevy_ecs::world: Despawning entity 0v0
```
# Objective
- While animating 501 https://github.com/KhronosGroup/glTF-Sample-Models/tree/master/2.0/BrainStem, I noticed things were getting a little slow
- Looking in tracy, the system `extract_skinned_meshes` is taking a lot of time, with a mean duration of 15.17ms
## Solution
- ~~Use `Vec` instead of a `SmallVec`~~
- ~~Don't use an temporary variable~~
- Compute the affine matrix as an `Affine3A` instead
- Remove the `temp` vec
| |mean|
|---|---|
|base|15.17ms|
|~~vec~~|~~9.31ms~~|
|~~no temp variable~~|~~11.31ms~~|
|removing the temp vector|8.43ms|
|affine|13.21ms|
|all together|7.23ms|
# Objective
- Improve transform propagation performance
## Solution
- Use `Changed<Transform>` as part of the `root_query` and `transform_query` to avoid the indirection of having to look up the `Entity` in the `changed_transform_query`
- Get rid of the `changed_transform_query` entirely
- `transform_propagate_system` execution time for `many_cubes -- sphere` dropped from 1.07ms to 0.159ms, an 85% reduction for this system. Frame rate increased from ~42fps to ~44fps
# Objective
- Hierarchy tools are not just used for `Transform`: they are also used for scenes.
- In the future there's interest in using them for other features, such as visiibility inheritance.
- The fact that these tools are found in `bevy_transform` causes a great deal of user and developer confusion
- Fixes#2758.
## Solution
- Split `bevy_transform` into two!
- Make everything work again.
Note that this is a very tightly scoped PR: I *know* there are code quality and docs issues that existed in bevy_transform that I've just moved around. We should fix those in a seperate PR and try to merge this ASAP to reduce the bitrot involved in splitting an entire crate.
## Frustrations
The API around `GlobalTransform` is a mess: we have massive code and docs duplication, no link between the two types and no clear way to extend this to other forms of inheritance.
In the medium-term, I feel pretty strongly that `GlobalTransform` should be replaced by something like `Inherited<Transform>`, which lives in `bevy_hierarchy`:
- avoids code duplication
- makes the inheritance pattern extensible
- links the types at the type-level
- allows us to remove all references to inheritance from `bevy_transform`, making it more useful as a standalone crate and cleaning up its docs
## Additional context
- double-blessed by @cart in https://github.com/bevyengine/bevy/issues/4141#issuecomment-1063592414 and https://github.com/bevyengine/bevy/issues/2758#issuecomment-913810963
- preparation for more advanced / cleaner hierarchy tools: go read https://github.com/bevyengine/rfcs/pull/53 !
- originally attempted by @finegeometer in #2789. It was a great idea, just needed more discussion!
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
Lets say we need to rotate stretched object for this purpose we can created stretched `Child` and add as child to `Parent`, later we can rotate `Parent`, `Child` in this situation should rotate keeping it form, it is not the case with `SpriteBundle` currently. If you try to do it with `SpriteBundle` it will deform.
## Solution
My pull request fixes order of transformations to scale -> rotate -> translate, with this fix `SpriteBundle` behaves as expected in described rotation, without deformation. Here is quote from "Essential Mathematics for Games":
> Generally, the desired order we wish to use for these transforms is to scale first, then rotate, then translate. Scaling first gives us the scaling along the axes we expect. We can then rotate around the origin of the frame, and then translate it into place.
I'm must say when I was using `MaterialMesh2dBundle` it behaves correctly in both cases with `bevy main` and with my fix, don't know why, was not able to figure it out why there is difference.
here is code I was using for testing:
```rust
use bevy::{
prelude::*,
render::render_resource::{Extent3d, TextureDimension, TextureFormat},
sprite::{MaterialMesh2dBundle, Mesh2dHandle},
};
fn main() {
let mut app = App::new();
app.insert_resource(ClearColor(Color::rgb(0.1, 0.2, 0.3)))
.add_plugins(DefaultPlugins)
.add_startup_system(setup);
app.run();
}
fn setup(
mut commands: Commands,
mut images: ResMut<Assets<Image>>,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<ColorMaterial>>,
) {
let mut c = OrthographicCameraBundle::new_2d();
c.orthographic_projection.scale = 1.0 / 10.0;
commands.spawn_bundle(c);
// note: mesh somehow works for both variants
// let quad: Mesh2dHandle = meshes.add(Mesh::from(shape::Quad::default())).into();
// let child = commands
// .spawn_bundle(MaterialMesh2dBundle {
// mesh: quad.clone(),
// transform: Transform::from_translation(Vec3::new(0.0, 0.0, -1.0))
// .with_scale(Vec3::new(10.0, 1.0, 1.0)),
// material: materials.add(ColorMaterial::from(Color::BLACK)),
// ..Default::default()
// })
// .id();
// commands
// .spawn_bundle(MaterialMesh2dBundle {
// mesh: quad,
// transform: Transform::from_rotation(Quat::from_rotation_z(0.78))
// .with_translation(Vec3::new(0.0, 0.0, 10.0)),
// material: materials.add(ColorMaterial::from(Color::WHITE)),
// ..Default::default()
// })
// .push_children(&[child]);
let white = images.add(get_image(Color::rgb(1.0, 1.0, 1.0)));
let black = images.add(get_image(Color::rgb(0.0, 0.0, 0.0)));
let child = commands
.spawn_bundle(SpriteBundle {
texture: black,
transform: Transform::from_translation(Vec3::new(0.0, 0.0, -1.0))
.with_scale(Vec3::new(10.0, 1.0, 1.0)),
..Default::default()
})
.id();
commands
.spawn_bundle(SpriteBundle {
texture: white,
transform: Transform::from_rotation(Quat::from_rotation_z(0.78))
.with_translation(Vec3::new(0.0, 0.0, 10.0)),
..Default::default()
})
.push_children(&[child]);
}
fn get_image(color: Color) -> Image {
let mut bytes = Vec::with_capacity((1 * 1 * 4 * 4) as usize);
let color = color.as_rgba_f32();
bytes.extend(color[0].to_le_bytes());
bytes.extend(color[1].to_le_bytes());
bytes.extend(color[2].to_le_bytes());
bytes.extend(1.0_f32.to_le_bytes());
Image::new(
Extent3d {
width: 1,
height: 1,
depth_or_array_layers: 1,
},
TextureDimension::D2,
bytes,
TextureFormat::Rgba32Float,
)
}
```
here is screenshot with `bevy main` and my fix:
What is says on the tin.
This has got more to do with making `clippy` slightly more *quiet* than it does with changing anything that might greatly impact readability or performance.
that said, deriving `Default` for a couple of structs is a nice easy win
# Objective
- Bevy currently has no simple way to make an "empty" Entity work correctly in a Hierachy.
- The current Solution is to insert a Tuple instead:
```rs
.insert_bundle((Transform::default(), GlobalTransform::default()))
```
## Solution
* Add a `TransformBundle` that combines the Components:
```rs
.insert_bundle(TransformBundle::default())
```
* The code is based on #2331, except for missing the more controversial usage of `TransformBundle` as a Sub-bundle in preexisting Bundles.
Co-authored-by: MinerSebas <66798382+MinerSebas@users.noreply.github.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- Missing obvious way to rotate a transform around a point. This is popularly used for rotation of an object in world space ("orbiting" a point), or for local rotation of an object around a pivot point on that object.
- Present in other (not to be named) game engines
- Was question from user on Discord today (thread "object rotation")
## Solution
- Added Transform::rotate_around method where point is specified in reference frame of the parent (if any) or in world space.
# Objective
bevy_transform needed documentation and warn(missing_docs) as requested by #3492
## Solution
warn(missing_docs) was activated and documentation was added to cover the crate
Co-authored-by: Troels Jessen <kairyuka@gmail.com>
# Objective
CI should check for missing backticks in doc comments.
Fixes#3435
## Solution
`clippy` has a lint for this: `doc_markdown`. This enables that lint in the CI script.
Of course, enabling this lint in CI causes a bunch of lint errors, so I've gone through and fixed all of them. This was a huge edit that touched a ton of files, so I split the PR up by crate.
When all of the following are merged, the CI should pass and this can be merged.
+ [x] #3467
+ [x] #3468
+ [x] #3470
+ [x] #3469
+ [x] #3471
+ [x] #3472
+ [x] #3473
+ [x] #3474
+ [x] #3475
+ [x] #3476
+ [x] #3477
+ [x] #3478
+ [x] #3479
+ [x] #3480
+ [x] #3481
+ [x] #3482
+ [x] #3483
+ [x] #3484
+ [x] #3485
+ [x] #3486
#3457 adds the `doc_markdown` clippy lint, which checks doc comments to make sure code identifiers are escaped with backticks. This causes a lot of lint errors, so this is one of a number of PR's that will fix those lint errors one crate at a time.
This PR fixes lints in the `bevy_transform` crate.
# Objective
Fix#2406
Scene parenting was not done completely, leaving the hierarchy maintenance to the standard system. As scene spawning happens in stage `PreUpdate` and hierarchy maintenance in stage `PostUpdate`, this left the scene in an invalid state parent wise for part of a frame
## Solution
Also add/update the `Children` component when spawning the scene.
I kept the `Children` component as a `SmallVec`, it could be moved to an `HashSet` to guarantee uniqueness
Co-authored-by: François <8672791+mockersf@users.noreply.github.com>
Fixes#2566Fixes#3005
There are only READMEs in the 4 crates here (with the exception of bevy itself).
Those 4 crates are ecs, reflect, tasks, and transform.
These should each now include their respective README files.
Co-authored-by: Hoidigan <57080125+Hoidigan@users.noreply.github.com>
Co-authored-by: Daniel Nelsen <57080125+Hoidigan@users.noreply.github.com>
# Objective
- `bevy_ecs` exposes as an optional feature `bevy_reflect`. Disabling it doesn't compile.
- `bevy_asset` exposes as an optional feature `filesystem_watcher`. Disabling it doesn't compile. It is also not possible to disable this feature from Bevy
## Solution
- Fix compilation errors when disabling the default features. Make it possible to disable the feature `filesystem_watcher` from Bevy
Objective
During work on #3009 I've found that not all jobs use actions-rs, and therefore, an previous version of Rust is used for them. So while compilation and other stuff can pass, checking markup and Android build may fail with compilation errors.
Solution
This PR adds `action-rs` for any job running cargo, and updates the edition to 2021.
This implements the most minimal variant of #1843 - a derive for marker trait. This is a prerequisite to more complicated features like statically defined storage type or opt-out component reflection.
In order to make component struct's purpose explicit and avoid misuse, it must be annotated with `#[derive(Component)]` (manual impl is discouraged for compatibility). Right now this is just a marker trait, but in the future it might be expanded. Making this change early allows us to make further changes later without breaking backward compatibility for derive macro users.
This already prevents a lot of issues, like using bundles in `insert` calls. Primitive types are no longer valid components as well. This can be easily worked around by adding newtype wrappers and deriving `Component` for them.
One funny example of prevented bad code (from our own tests) is when an newtype struct or enum variant is used. Previously, it was possible to write `insert(Newtype)` instead of `insert(Newtype(value))`. That code compiled, because function pointers (in this case newtype struct constructor) implement `Send + Sync + 'static`, so we allowed them to be used as components. This is no longer the case and such invalid code will trigger a compile error.
Co-authored-by: = <=>
Co-authored-by: TheRawMeatball <therawmeatball@gmail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
Noticed a comment saying changed detection should be enabled for hierarchy maintenance once stable
Fixes#891
## Solution
Added `Changed<Parent>` filter on the query
# Objective
Make it easier to construct transforms. E.g.
```rs
Transform::from_xyz(0.0, 0.0, 10.0).with_scale(Vec3::splat(2.0))
```
I found myself writing an extension method to do this so I don't have to write:
```rs
Transform {
translation: Vec3::new(0.0, 0.0, 10.0),
scale: Vec3::splat(2.0),
..Default::default()
}
```
## Solution
Add *builder style* methods to `Transform`.
Methods:
- `with_translation`
- `with_rotation`
- `with_scale`
I also added these methods to `GlobalTransform`. But they are probably less useful there.
# Objective
Enable using exact World lifetimes during read-only access . This is motivated by the new renderer's need to allow read-only world-only queries to outlive the query itself (but still be constrained by the world lifetime).
For example:
115b170d1f/pipelined/bevy_pbr2/src/render/mod.rs (L774)
## Solution
Split out SystemParam state and world lifetimes and pipe those lifetimes up to read-only Query ops (and add into_inner for Res). According to every safety test I've run so far (except one), this is safe (see the temporary safety test commit). Note that changing the mutable variants to the new lifetimes would allow aliased mutable pointers (try doing that to see how it affects the temporary safety tests).
The new state lifetime on SystemParam does make `#[derive(SystemParam)]` more cumbersome (the current impl requires PhantomData if you don't use both lifetimes). We can make this better by detecting whether or not a lifetime is used in the derive and adjusting accordingly, but that should probably be done in its own pr.
## Why is this a draft?
The new lifetimes break QuerySet safety in one very specific case (see the query_set system in system_safety_test). We need to solve this before we can use the lifetimes given.
This is due to the fact that QuerySet is just a wrapper over Query, which now relies on world lifetimes instead of `&self` lifetimes to prevent aliasing (but in systems, each Query has its own implied lifetime, not a centralized world lifetime). I believe the fix is to rewrite QuerySet to have its own World lifetime (and own the internal reference). This will complicate the impl a bit, but I think it is doable. I'm curious if anyone else has better ideas.
Personally, I think these new lifetimes need to happen. We've gotta have a way to directly tie read-only World queries to the World lifetime. The new renderer is the first place this has come up, but I doubt it will be the last. Worst case scenario we can come up with a second `WorldLifetimeQuery<Q, F = ()>` parameter to enable these read-only scenarios, but I'd rather not add another type to the type zoo.
## Objective
- Clean up remaining references to the trait `FromResources`, which was replaced in favor of `FromWorld` during the ECS rework.
## Solution
- Remove the derive macro for `FromResources`
- Change doc references of `FromResources` to `FromWorld`
(this is the first item in #2576)
## Objective
This code would result in a crash:
```rust
use bevy::prelude::*;
fn main() {
let mut world = World::new();
let child = world.spawn().id();
world.spawn().push_children(&[child]);
}
```
## Solution
Update the `EntityMut`'s location after inserting a component on the children entities, as it may have changed.
# Objective
- Remove all the `.system()` possible.
- Check for remaining missing cases.
## Solution
- Remove all `.system()`, fix compile errors
- 32 calls to `.system()` remains, mostly internals, the few others should be removed after #2446
This is extracted out of eb8f973646476b4a4926ba644a77e2b3a5772159 and includes some additional changes to remove all references to AppBuilder and fix examples that still used App::build() instead of App::new(). In addition I didn't extract the sub app feature as it isn't ready yet.
You can use `git diff --diff-filter=M eb8f973646476b4a4926ba644a77e2b3a5772159` to find all differences in this PR. The `--diff-filtered=M` filters all files added in the original commit but not in this commit away.
Co-Authored-By: Carter Anderson <mcanders1@gmail.com>
* bevy_pbr2: Add support for most of the StandardMaterial textures
Normal maps are not included here as they require tangents in a vertex attribute.
* bevy_pbr2: Ensure RenderCommandQueue is ready for PbrShaders init
* texture_pipelined: Add a light to the scene so we can see stuff
* WIP bevy_pbr2: back to front sorting hack
* bevy_pbr2: Uniform control flow for texture sampling in pbr.frag
From 'fintelia' on the Bevy Render Rework Round 2 discussion:
"My understanding is that GPUs these days never use the "execute both branches
and select the result" strategy. Rather, what they do is evaluate the branch
condition on all threads of a warp, and jump over it if all of them evaluate to
false. If even a single thread needs to execute the if statement body, however,
then the remaining threads are paused until that is completed."
* bevy_pbr2: Simplify texture and sampler names
The StandardMaterial_ prefix is no longer needed
* bevy_pbr2: Match default 'AmbientColor' of current bevy_pbr for now
* bevy_pbr2: Convert from non-linear to linear sRGB for the color uniform
* bevy_pbr2: Add pbr_pipelined example
* Fix view vector in pbr frag to work in ortho
* bevy_pbr2: Use a 90 degree y fov and light range projection for lights
* bevy_pbr2: Add AmbientLight resource
* bevy_pbr2: Convert PointLight color to linear sRGB for use in fragment shader
* bevy_pbr2: pbr.frag: Rename PointLight.projection to view_projection
The uniform contains the view_projection matrix so this was incorrect.
* bevy_pbr2: PointLight is an OmniLight as it has a radius
* bevy_pbr2: Factoring out duplicated code
* bevy_pbr2: Implement RenderAsset for StandardMaterial
* Remove unnecessary texture and sampler clones
* fix comment formatting
* remove redundant Buffer:from
* Don't extract meshes when their material textures aren't ready
* make missing textures in the queue step an error
Co-authored-by: Aevyrie <aevyrie@gmail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
This relicenses Bevy under the dual MIT or Apache-2.0 license. For rationale, see #2373.
* Changes the LICENSE file to describe the dual license. Moved the MIT license to docs/LICENSE-MIT. Added the Apache-2.0 license to docs/LICENSE-APACHE. I opted for this approach over dumping both license files at the root (the more common approach) for a number of reasons:
* Github links to the "first" license file (LICENSE-APACHE) in its license links (you can see this in the wgpu and rust-analyzer repos). People clicking these links might erroneously think that the apache license is the only option. Rust and Amethyst both use COPYRIGHT or COPYING files to solve this problem, but this creates more file noise (if you do everything at the root) and the naming feels way less intuitive.
* People have a reflex to look for a LICENSE file. By providing a single license file at the root, we make it easy for them to understand our licensing approach.
* I like keeping the root clean and noise free
* There is precedent for putting the apache and mit license text in sub folders (amethyst)
* Removed the `Copyright (c) 2020 Carter Anderson` copyright notice from the MIT license. I don't care about this attribution, it might make license compliance more difficult in some cases, and it didn't properly attribute other contributors. We shoudn't replace it with something like "Copyright (c) 2021 Bevy Contributors" because "Bevy Contributors" is not a legal entity. Instead, we just won't include the copyright line (which has precedent ... Rust also uses this approach).
* Updates crates to use the new "MIT OR Apache-2.0" license value
* Removes the old legion-transform license file from bevy_transform. bevy_transform has been its own, fully custom implementation for a long time and that license no longer applies.
* Added a License section to the main readme
* Updated our Bevy Plugin licensing guidelines.
As a follow-up we should update the website to properly describe the new license.
Closes#2373
# Objective
- Currently `Commands` are quite slow due to the need to allocate for each command and wrap it in a `Box<dyn Command>`.
- For example:
```rust
fn my_system(mut cmds: Commands) {
cmds.spawn().insert(42).insert(3.14);
}
```
will have 3 separate `Box<dyn Command>` that need to be allocated and ran.
## Solution
- Utilize a specialized data structure keyed `CommandQueueInner`.
- The purpose of `CommandQueueInner` is to hold a collection of commands in contiguous memory.
- This allows us to store each `Command` type contiguously in memory and quickly iterate through them and apply the `Command::write` trait function to each element.
# Objective
- CI jobs are starting to fail due to `clippy::bool-assert-comparison` and `clippy::single_component_path_imports` being triggered.
## Solution
- Fix all uses where `asset_eq!(<condition>, <bool>)` could be replace by `assert!`
- Move the `#[allow()]` for `single_component_path_imports` to `#![allow()]` at the start of the files.
Continuing the work on reducing the safety footguns in the code, I've removed one extra `UnsafeCell` in favour of safe `Cell` usage inisde `ComponentTicks`. That change led to discovery of misbehaving component insert logic, where data wasn't properly dropped when overwritten. Apart from that being fixed, some method names were changed to better convey the "initialize new allocation" and "replace existing allocation" semantic.
Depends on #2221, I will rebase this PR after the dependency is merged. For now, review just the last commit.
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
Fixes#2274
When calling `despawn_recursive`, the recursive loop doesn't need to remove the entity from the children list of its parent when the parent will also be deleted
Upside:
* Removes two entity lookup per entity being recursively despawned
Downside:
* The change detection on the `Children` component of a deleted entity in the despawned hierarchy will not be triggered
The only API to add a parent/child relationship between existing entities is through commands, there is no easy way to do it from `World`. Manually inserting the components is not completely possible since `PreviousParent` has no public constructor.
This PR adds two methods to set entities as children of an `EntityMut`: `insert_children` and `push_children`. ~~The API is similar to the one on `Commands`, except that the parent is the `EntityMut`.~~ The API is the same as in #1703.
However, the `Parent` and `Children` components are defined in `bevy_transform` which depends on `bevy_ecs`, while `EntityMut` is defined in `bevy_ecs`, so the methods are added to the `BuildWorldChildren` trait instead.
If #1545 is merged this should be fixed too.
I'm aware cart was experimenting with entity hierarchies, but unless it's a coming soon this PR would be useful to have meanwhile.
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
Resolves#1253#1562
This makes the Commands apis consistent with World apis. This moves to a "type state" pattern (like World) where the "current entity" is stored in an `EntityCommands` builder.
In general this tends to cuts down on indentation and line count. It comes at the cost of needing to type `commands` more and adding more semicolons to terminate expressions.
I also added `spawn_bundle` to Commands because this is a common enough operation that I think its worth providing a shorthand.
fixes#1599
* Added doc on `Transform` and `GlobalTransform` to describe usage and how `GlobalTransform` is updated
* Documented all methods on `Transform`
* `#[doc(hidden)]` most constructors and methods mutating `GlobalTransform`, documented the other
* Mentioned z-ordering for `Transform` in 2d
