# Objective
Component `require()` IDE integration is fully broken, as of #16575.
## Solution
This reverts us back to the previous "put the docs on Component trait"
impl. This _does_ reduce the accessibility of the required components in
rust docs, but the complete erasure of "required component IDE
experience" is not worth the price of slightly increased prominence of
requires in docs.
Additionally, Rust Analyzer has recently started including derive
attributes in suggestions, so we aren't losing that benefit of the
proc_macro attribute impl.
# Objective
- Fixes#17960
## Solution
- Followed the [edition upgrade
guide](https://doc.rust-lang.org/edition-guide/editions/transitioning-an-existing-project-to-a-new-edition.html)
## Testing
- CI
---
## Summary of Changes
### Documentation Indentation
When using lists in documentation, proper indentation is now linted for.
This means subsequent lines within the same list item must start at the
same indentation level as the item.
```rust
/* Valid */
/// - Item 1
/// Run-on sentence.
/// - Item 2
struct Foo;
/* Invalid */
/// - Item 1
/// Run-on sentence.
/// - Item 2
struct Foo;
```
### Implicit `!` to `()` Conversion
`!` (the never return type, returned by `panic!`, etc.) no longer
implicitly converts to `()`. This is particularly painful for systems
with `todo!` or `panic!` statements, as they will no longer be functions
returning `()` (or `Result<()>`), making them invalid systems for
functions like `add_systems`. The ideal fix would be to accept functions
returning `!` (or rather, _not_ returning), but this is blocked on the
[stabilisation of the `!` type
itself](https://doc.rust-lang.org/std/primitive.never.html), which is
not done.
The "simple" fix would be to add an explicit `-> ()` to system
signatures (e.g., `|| { todo!() }` becomes `|| -> () { todo!() }`).
However, this is _also_ banned, as there is an existing lint which (IMO,
incorrectly) marks this as an unnecessary annotation.
So, the "fix" (read: workaround) is to put these kinds of `|| -> ! { ...
}` closuers into variables and give the variable an explicit type (e.g.,
`fn()`).
```rust
// Valid
let system: fn() = || todo!("Not implemented yet!");
app.add_systems(..., system);
// Invalid
app.add_systems(..., || todo!("Not implemented yet!"));
```
### Temporary Variable Lifetimes
The order in which temporary variables are dropped has changed. The
simple fix here is _usually_ to just assign temporaries to a named
variable before use.
### `gen` is a keyword
We can no longer use the name `gen` as it is reserved for a future
generator syntax. This involved replacing uses of the name `gen` with
`r#gen` (the raw-identifier syntax).
### Formatting has changed
Use statements have had the order of imports changed, causing a
substantial +/-3,000 diff when applied. For now, I have opted-out of
this change by amending `rustfmt.toml`
```toml
style_edition = "2021"
```
This preserves the original formatting for now, reducing the size of
this PR. It would be a simple followup to update this to 2024 and run
`cargo fmt`.
### New `use<>` Opt-Out Syntax
Lifetimes are now implicitly included in RPIT types. There was a handful
of instances where it needed to be added to satisfy the borrow checker,
but there may be more cases where it _should_ be added to avoid
breakages in user code.
### `MyUnitStruct { .. }` is an invalid pattern
Previously, you could match against unit structs (and unit enum
variants) with a `{ .. }` destructuring. This is no longer valid.
### Pretty much every use of `ref` and `mut` are gone
Pattern binding has changed to the point where these terms are largely
unused now. They still serve a purpose, but it is far more niche now.
### `iter::repeat(...).take(...)` is bad
New lint recommends using the more explicit `iter::repeat_n(..., ...)`
instead.
## Migration Guide
The lifetimes of functions using return-position impl-trait (RPIT) are
likely _more_ conservative than they had been previously. If you
encounter lifetime issues with such a function, please create an issue
to investigate the addition of `+ use<...>`.
## Notes
- Check the individual commits for a clearer breakdown for what
_actually_ changed.
---------
Co-authored-by: François Mockers <francois.mockers@vleue.com>
Two-phase occlusion culling can be helpful for shadow maps just as it
can for a prepass, in order to reduce vertex and alpha mask fragment
shading overhead. This patch implements occlusion culling for shadow
maps from directional lights, when the `OcclusionCulling` component is
present on the entities containing the lights. Shadow maps from point
lights are deferred to a follow-up patch. Much of this patch involves
expanding the hierarchical Z-buffer to cover shadow maps in addition to
standard view depth buffers.
The `scene_viewer` example has been updated to add `OcclusionCulling` to
the directional light that it creates.
This improved the performance of the rend3 sci-fi test scene when
enabling shadows.
Currently, Bevy's implementation of bindless resources is rather
unusual: every binding in an object that implements `AsBindGroup` (most
commonly, a material) becomes its own separate binding array in the
shader. This is inefficient for two reasons:
1. If multiple materials reference the same texture or other resource,
the reference to that resource will be duplicated many times. This
increases `wgpu` validation overhead.
2. It creates many unused binding array slots. This increases `wgpu` and
driver overhead and makes it easier to hit limits on APIs that `wgpu`
currently imposes tight resource limits on, like Metal.
This PR fixes these issues by switching Bevy to use the standard
approach in GPU-driven renderers, in which resources are de-duplicated
and passed as global arrays, one for each type of resource.
Along the way, this patch introduces per-platform resource limits and
bumps them from 16 resources per binding array to 64 resources per bind
group on Metal and 2048 resources per bind group on other platforms.
(Note that the number of resources per *binding array* isn't the same as
the number of resources per *bind group*; as it currently stands, if all
the PBR features are turned on, Bevy could pack as many as 496 resources
into a single slab.) The limits have been increased because `wgpu` now
has universal support for partially-bound binding arrays, which mean
that we no longer need to fill the binding arrays with fallback
resources on Direct3D 12. The `#[bindless(LIMIT)]` declaration when
deriving `AsBindGroup` can now simply be written `#[bindless]` in order
to have Bevy choose a default limit size for the current platform.
Custom limits are still available with the new
`#[bindless(limit(LIMIT))]` syntax: e.g. `#[bindless(limit(8))]`.
The material bind group allocator has been completely rewritten. Now
there are two allocators: one for bindless materials and one for
non-bindless materials. The new non-bindless material allocator simply
maintains a 1:1 mapping from material to bind group. The new bindless
material allocator maintains a list of slabs and allocates materials
into slabs on a first-fit basis. This unfortunately makes its
performance O(number of resources per object * number of slabs), but the
number of slabs is likely to be low, and it's planned to become even
lower in the future with `wgpu` improvements. Resources are
de-duplicated with in a slab and reference counted. So, for instance, if
multiple materials refer to the same texture, that texture will exist
only once in the appropriate binding array.
To support these new features, this patch adds the concept of a
*bindless descriptor* to the `AsBindGroup` trait. The bindless
descriptor allows the material bind group allocator to probe the layout
of the material, now that an array of `BindGroupLayoutEntry` records is
insufficient to describe the group. The `#[derive(AsBindGroup)]` has
been heavily modified to support the new features. The most important
user-facing change to that macro is that the struct-level `uniform`
attribute, `#[uniform(BINDING_NUMBER, StandardMaterial)]`, now reads
`#[uniform(BINDLESS_INDEX, MATERIAL_UNIFORM_TYPE,
binding_array(BINDING_NUMBER)]`, allowing the material to specify the
binding number for the binding array that holds the uniform data.
To make this patch simpler, I removed support for bindless
`ExtendedMaterial`s, as well as field-level bindless uniform and storage
buffers. I intend to add back support for these as a follow-up. Because
they aren't in any released Bevy version yet, I figured this was OK.
Finally, this patch updates `StandardMaterial` for the new bindless
changes. Generally, code throughout the PBR shaders that looked like
`base_color_texture[slot]` now looks like
`bindless_2d_textures[material_indices[slot].base_color_texture]`.
This patch fixes a system hang that I experienced on the [Caldera test]
when running with `caldera --random-materials --texture-count 100`. The
time per frame is around 19.75 ms, down from 154.2 ms in Bevy 0.14: a
7.8× speedup.
[Caldera test]: https://github.com/DGriffin91/bevy_caldera_scene
Deferred rendering currently doesn't support occlusion culling. This PR
implements it in a straightforward way, mirroring what we already do for
the non-deferred pipeline.
On the rend3 sci-fi base test scene, this resulted in roughly a 2×
speedup when applied on top of my other patches. For that scene, it was
useful to add another option, `--add-light`, which forces the addition
of a shadow-casting light, to the scene viewer, which I included in this
patch.
Currently, Bevy rebuilds the buffer containing all the transforms for
joints every frame, during the extraction phase. This is inefficient in
cases in which many skins are present in the scene and their joints
don't move, such as the Caldera test scene.
To address this problem, this commit switches skin extraction to use a
set of retained GPU buffers with allocations managed by the offset
allocator. I use fine-grained change detection in order to determine
which skins need updating. Note that the granularity is on the level of
an entire skin, not individual joints. Using the change detection at
that level would yield poor performance in common cases in which an
entire skin is animated at once. Also, this patch yields additional
performance from the fact that changing joint transforms no longer
requires the skinned mesh to be re-extracted.
Note that this optimization can be a double-edged sword. In
`many_foxes`, fine-grained change detection regressed the performance of
`extract_skins` by 3.4x. This is because every joint is updated every
frame in that example, so change detection is pointless and is pure
overhead. Because the `many_foxes` workload is actually representative
of animated scenes, this patch includes a heuristic that disables
fine-grained change detection if the number of transformed entities in
the frame exceeds a certain fraction of the total number of joints.
Currently, this threshold is set to 25%. Note that this is a crude
heuristic, because it doesn't distinguish between the number of
transformed *joints* and the number of transformed *entities*; however,
it should be good enough to yield the optimum code path most of the
time.
Finally, this patch fixes a bug whereby skinned meshes are actually
being incorrectly retained if the buffer offsets of the joints of those
skinned meshes changes from frame to frame. To fix this without
retaining skins, we would have to re-extract every skinned mesh every
frame. Doing this was a significant regression on Caldera. With this PR,
by contrast, mesh joints stay at the same buffer offset, so we don't
have to update the `MeshInputUniform` containing the buffer offset every
frame. This also makes PR #17717 easier to implement, because that PR
uses the buffer offset from the previous frame, and the logic for
calculating that is simplified if the previous frame's buffer offset is
guaranteed to be identical to that of the current frame.
On Caldera, this patch reduces the time spent in `extract_skins` from
1.79 ms to near zero. On `many_foxes`, this patch regresses the
performance of `extract_skins` by approximately 10%-25%, depending on
the number of foxes. This has only a small impact on frame rate.
* Use texture atomics rather than buffer atomics for the visbuffer
(haven't tested perf on a raster-heavy scene yet)
* Unfortunately to clear the visbuffer we now need a compute pass to
clear it. Using wgpu's clear_texture function internally uses a buffer
-> image copy that's insanely expensive. Ideally it should be using
vkCmdClearColorImage, which I've opened an issue for
https://github.com/gfx-rs/wgpu/issues/7090. For now we'll have to stick
with a custom compute pass and all the extra code that brings.
* Faster resolve depth pass by discarding 0 depth pixels instead of
redundantly writing zero (2x faster for big depth textures like shadow
views)
# Objective
Because of mesh preprocessing, users cannot rely on
`@builtin(instance_index)` in order to reference external data, as the
instance index is not stable, either from frame to frame or relative to
the total spawn order of mesh instances.
## Solution
Add a user supplied mesh index that can be used for referencing external
data when drawing instanced meshes.
Closes#13373
## Testing
Benchmarked `many_cubes` showing no difference in total frame time.
## Showcase
https://github.com/user-attachments/assets/80620147-aafc-4d9d-a8ee-e2149f7c8f3b
---------
Co-authored-by: IceSentry <IceSentry@users.noreply.github.com>
Didn't remove WgpuWrapper. Not sure if it's needed or not still.
## Testing
- Did you test these changes? If so, how? Example runner
- Are there any parts that need more testing? Web (portable atomics
thingy?), DXC.
## Migration Guide
- Bevy has upgraded to [wgpu
v24](https://github.com/gfx-rs/wgpu/blob/trunk/CHANGELOG.md#v2400-2025-01-15).
- When using the DirectX 12 rendering backend, the new priority system
for choosing a shader compiler is as follows:
- If the `WGPU_DX12_COMPILER` environment variable is set at runtime, it
is used
- Else if the new `statically-linked-dxc` feature is enabled, a custom
version of DXC will be statically linked into your app at compile time.
- Else Bevy will look in the app's working directory for
`dxcompiler.dll` and `dxil.dll` at runtime.
- Else if they are missing, Bevy will fall back to FXC (not recommended)
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: IceSentry <c.giguere42@gmail.com>
Co-authored-by: François Mockers <francois.mockers@vleue.com>
# Objective
- Make use of the new `weak_handle!` macro added in
https://github.com/bevyengine/bevy/pull/17384
## Solution
- Migrate bevy from `Handle::weak_from_u128` to the new `weak_handle!`
macro that takes a random UUID
- Deprecate `Handle::weak_from_u128`, since there are no remaining use
cases that can't also be addressed by constructing the type manually
## Testing
- `cargo run -p ci -- test`
---
## Migration Guide
Replace `Handle::weak_from_u128` with `weak_handle!` and a random UUID.
*Occlusion culling* allows the GPU to skip the vertex and fragment
shading overhead for objects that can be quickly proved to be invisible
because they're behind other geometry. A depth prepass already
eliminates most fragment shading overhead for occluded objects, but the
vertex shading overhead, as well as the cost of testing and rejecting
fragments against the Z-buffer, is presently unavoidable for standard
meshes. We currently perform occlusion culling only for meshlets. But
other meshes, such as skinned meshes, can benefit from occlusion culling
too in order to avoid the transform and skinning overhead for unseen
meshes.
This commit adapts the same [*two-phase occlusion culling*] technique
that meshlets use to Bevy's standard 3D mesh pipeline when the new
`OcclusionCulling` component, as well as the `DepthPrepass` component,
are present on the camera. It has these steps:
1. *Early depth prepass*: We use the hierarchical Z-buffer from the
previous frame to cull meshes for the initial depth prepass, effectively
rendering only the meshes that were visible in the last frame.
2. *Early depth downsample*: We downsample the depth buffer to create
another hierarchical Z-buffer, this time with the current view
transform.
3. *Late depth prepass*: We use the new hierarchical Z-buffer to test
all meshes that weren't rendered in the early depth prepass. Any meshes
that pass this check are rendered.
4. *Late depth downsample*: Again, we downsample the depth buffer to
create a hierarchical Z-buffer in preparation for the early depth
prepass of the next frame. This step is done after all the rendering, in
order to account for custom phase items that might write to the depth
buffer.
Note that this patch has no effect on the per-mesh CPU overhead for
occluded objects, which remains high for a GPU-driven renderer due to
the lack of `cold-specialization` and retained bins. If
`cold-specialization` and retained bins weren't on the horizon, then a
more traditional approach like potentially visible sets (PVS) or low-res
CPU rendering would probably be more efficient than the GPU-driven
approach that this patch implements for most scenes. However, at this
point the amount of effort required to implement a PVS baking tool or a
low-res CPU renderer would probably be greater than landing
`cold-specialization` and retained bins, and the GPU driven approach is
the more modern one anyway. It does mean that the performance
improvements from occlusion culling as implemented in this patch *today*
are likely to be limited, because of the high CPU overhead for occluded
meshes.
Note also that this patch currently doesn't implement occlusion culling
for 2D objects or shadow maps. Those can be addressed in a follow-up.
Additionally, note that the techniques in this patch require compute
shaders, which excludes support for WebGL 2.
This PR is marked experimental because of known precision issues with
the downsampling approach when applied to non-power-of-two framebuffer
sizes (i.e. most of them). These precision issues can, in rare cases,
cause objects to be judged occluded that in fact are not. (I've never
seen this in practice, but I know it's possible; it tends to be likelier
to happen with small meshes.) As a follow-up to this patch, we desire to
switch to the [SPD-based hi-Z buffer shader from the Granite engine],
which doesn't suffer from these problems, at which point we should be
able to graduate this feature from experimental status. I opted not to
include that rewrite in this patch for two reasons: (1) @JMS55 is
planning on doing the rewrite to coincide with the new availability of
image atomic operations in Naga; (2) to reduce the scope of this patch.
A new example, `occlusion_culling`, has been added. It demonstrates
objects becoming quickly occluded and disoccluded by dynamic geometry
and shows the number of objects that are actually being rendered. Also,
a new `--occlusion-culling` switch has been added to `scene_viewer`, in
order to make it easy to test this patch with large scenes like Bistro.
[*two-phase occlusion culling*]:
https://medium.com/@mil_kru/two-pass-occlusion-culling-4100edcad501
[Aaltonen SIGGRAPH 2015]:
https://www.advances.realtimerendering.com/s2015/aaltonenhaar_siggraph2015_combined_final_footer_220dpi.pdf
[Some literature]:
https://gist.github.com/reduz/c5769d0e705d8ab7ac187d63be0099b5?permalink_comment_id=5040452#gistcomment-5040452
[SPD-based hi-Z buffer shader from the Granite engine]:
https://github.com/Themaister/Granite/blob/master/assets/shaders/post/hiz.comp
## Migration guide
* When enqueuing a custom mesh pipeline, work item buffers are now
created with
`bevy::render::batching::gpu_preprocessing::get_or_create_work_item_buffer`,
not `PreprocessWorkItemBuffers::new`. See the
`specialized_mesh_pipeline` example.
## Showcase
Occlusion culling example:

Bistro zoomed out, before occlusion culling:

Bistro zoomed out, after occlusion culling:

In this scene, occlusion culling reduces the number of meshes Bevy has
to render from 1591 to 585.
# Objective
- Contributes to #16877
## Solution
- Moved `hashbrown`, `foldhash`, and related types out of `bevy_utils`
and into `bevy_platform_support`
- Refactored the above to match the layout of these types in `std`.
- Updated crates as required.
## Testing
- CI
---
## Migration Guide
- The following items were moved out of `bevy_utils` and into
`bevy_platform_support::hash`:
- `FixedState`
- `DefaultHasher`
- `RandomState`
- `FixedHasher`
- `Hashed`
- `PassHash`
- `PassHasher`
- `NoOpHash`
- The following items were moved out of `bevy_utils` and into
`bevy_platform_support::collections`:
- `HashMap`
- `HashSet`
- `bevy_utils::hashbrown` has been removed. Instead, import from
`bevy_platform_support::collections` _or_ take a dependency on
`hashbrown` directly.
- `bevy_utils::Entry` has been removed. Instead, import from
`bevy_platform_support::collections::hash_map` or
`bevy_platform_support::collections::hash_set` as appropriate.
- All of the above equally apply to `bevy::utils` and
`bevy::platform_support`.
## Notes
- I left `PreHashMap`, `PreHashMapExt`, and `TypeIdMap` in `bevy_utils`
as they might be candidates for micro-crating. They can always be moved
into `bevy_platform_support` at a later date if desired.
Right now, we always include distance fog in the shader, which is
unfortunate as it's complex code and is rare. This commit changes it to
be a `#define` instead. I haven't confirmed that removing distance fog
meaningfully reduces VGPR usage, but it can't hurt.
This commit makes Bevy use change detection to only update
`RenderMaterialInstances` and `RenderMeshMaterialIds` when meshes have
been added, changed, or removed. `extract_mesh_materials`, the system
that extracts these, now follows the pattern that
`extract_meshes_for_gpu_building` established.
This improves frame time of `many_cubes` from 3.9ms to approximately
3.1ms, which slightly surpasses the performance of Bevy 0.14.
(Resubmitted from #16878 to clean up history.)

---------
Co-authored-by: Charlotte McElwain <charlotte.c.mcelwain@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
`bevy_ecs`'s `system` module is something of a grab bag, and *very*
large. This is particularly true for the `system_param` module, which is
more than 2k lines long!
While it could be defensible to put `Res` and `ResMut` there (lol no
they're in change_detection.rs, obviously), it doesn't make any sense to
put the `Resource` trait there. This is confusing to navigate (and
painful to work on and review).
## Solution
- Create a root level `bevy_ecs/resource.rs` module to mirror
`bevy_ecs/component.rs`
- move the `Resource` trait to that module
- move the `Resource` derive macro to that module as well (Rust really
likes when you pun on the names of the derive macro and trait and put
them in the same path)
- fix all of the imports
## Notes to reviewers
- We could probably move more stuff into here, but I wanted to keep this
PR as small as possible given the absurd level of import changes.
- This PR is ground work for my upcoming attempts to store resource data
on components (resources-as-entities). Splitting this code out will make
the work and review a bit easier, and is the sort of overdue refactor
that's good to do as part of more meaningful work.
## Testing
cargo build works!
## Migration Guide
`bevy_ecs::system::Resource` has been moved to
`bevy_ecs::resource::Resource`.
# Objective
The existing `RelationshipSourceCollection` uses `Vec` as the only
possible backing for our relationships. While a reasonable choice,
benchmarking use cases might reveal that a different data type is better
or faster.
For example:
- Not all relationships require a stable ordering between the
relationship sources (i.e. children). In cases where we a) have many
such relations and b) don't care about the ordering between them, a hash
set is likely a better datastructure than a `Vec`.
- The number of children-like entities may be small on average, and a
`smallvec` may be faster
## Solution
- Implement `RelationshipSourceCollection` for `EntityHashSet`, our
custom entity-optimized `HashSet`.
-~~Implement `DoubleEndedIterator` for `EntityHashSet` to make things
compile.~~
- This implementation was cursed and very surprising.
- Instead, by moving the iterator type on `RelationshipSourceCollection`
from an erased RPTIT to an explicit associated type we can add a trait
bound on the offending methods!
- Implement `RelationshipSourceCollection` for `SmallVec`
## Testing
I've added a pair of new tests to make sure this pattern compiles
successfully in practice!
## Migration Guide
`EntityHashSet` and `EntityHashMap` are no longer re-exported in
`bevy_ecs::entity` directly. If you were not using `bevy_ecs` / `bevy`'s
`prelude`, you can access them through their now-public modules,
`hash_set` and `hash_map` instead.
## Notes to reviewers
The `EntityHashSet::Iter` type needs to be public for this impl to be
allowed. I initially renamed it to something that wasn't ambiguous and
re-exported it, but as @Victoronz pointed out, that was somewhat
unidiomatic.
In
1a8564898f,
I instead made the `entity_hash_set` public (and its `entity_hash_set`)
sister public, and removed the re-export. I prefer this design (give me
module docs please), but it leads to a lot of churn in this PR.
Let me know which you'd prefer, and if you'd like me to split that
change out into its own micro PR.
# Objective
Many instances of `clippy::too_many_arguments` linting happen to be on
systems - functions which we don't call manually, and thus there's not
much reason to worry about the argument count.
## Solution
Allow `clippy::too_many_arguments` globally, and remove all lint
attributes related to it.
# Objective
Remove some outdated docs from 0.15 that mention a removed function.
## Solution
In `pbr_functions.wgsl`, I think it's fine to just remove the mention.
In `meshlet/asset.rs`, I think it would be nice to still have a note on
how texture samples should be done. Unfortunately, there isn't a nice
abstraction for it any more. Current workaround, for reference:
b386d08d0f/crates/bevy_pbr/src/render/pbr_fragment.wgsl (L184-L208)
For now, I've just removed the mention.
# Objective
- Contributes to #11478
## Solution
- Made `bevy_utils::tracing` `doc(hidden)`
- Re-exported `tracing` from `bevy_log` for end-users
- Added `tracing` directly to crates that need it.
## Testing
- CI
---
## Migration Guide
If you were importing `tracing` via `bevy::utils::tracing`, instead use
`bevy::log::tracing`. Note that many items within `tracing` are also
directly re-exported from `bevy::log` as well, so you may only need
`bevy::log` for the most common items (e.g., `warn!`, `trace!`, etc.).
This also applies to the `log_once!` family of macros.
## Notes
- While this doesn't reduce the line-count in `bevy_utils`, it further
decouples the internal crates from `bevy_utils`, making its eventual
removal more feasible in the future.
- I have just imported `tracing` as we do for all dependencies. However,
a workspace dependency may be more appropriate for version management.
# Objective
Improve DAG building for virtual geometry
## Solution
- Use METIS to group triangles into meshlets which lets us minimize
locked vertices which improves simplification, instead of using meshopt
which prioritizes culling efficiency. Also some other minor tweaks.
- Currently most meshlets have 126 triangles, and not 128. Fixing this
might involve calling METIS recursively ourselves to manually bisect the
graph, not sure. Not going to attempt to fix this in this PR.
## Testing
- Did you test these changes? If so, how?
- Tested on bunny.glb and cliff.glb
- Are there any parts that need more testing?
- No
- How can other people (reviewers) test your changes? Is there anything
specific they need to know?
- Download the new bunny asset, run the meshlet example.
---
## Showcase
New

Old

---------
Co-authored-by: IceSentry <IceSentry@users.noreply.github.com>
# Objective
- Fixes https://github.com/bevyengine/bevy/issues/16556
- Closes https://github.com/bevyengine/bevy/issues/11807
## Solution
- Simplify custom projections by using a single source of truth -
`Projection`, removing all existing generic systems and types.
- Existing perspective and orthographic structs are no longer components
- I could dissolve these to simplify further, but keeping them around
was the fast way to implement this.
- Instead of generics, introduce a third variant, with a trait object.
- Do an object safety dance with an intermediate trait to allow cloning
boxed camera projections. This is a normal rust polymorphism papercut.
You can do this with a crate but a manual impl is short and sweet.
## Testing
- Added a custom projection example
---
## Showcase
- Custom projections and projection handling has been simplified.
- Projection systems are no longer generic, with the potential for many
different projection components on the same camera.
- Instead `Projection` is now the single source of truth for camera
projections, and is the only projection component.
- Custom projections are still supported, and can be constructed with
`Projection::custom()`.
## Migration Guide
- `PerspectiveProjection` and `OrthographicProjection` are no longer
components. Use `Projection` instead.
- Custom projections should no longer be inserted as a component.
Instead, simply set the custom projection as a value of `Projection`
with `Projection::custom()`.
Revert the retry queue for stuck meshlet groups that couldn't simplify
added in https://github.com/bevyengine/bevy/pull/15886.
It was a hack that didn't really work, that was intended to help solve
meshlets getting stuck and never getting simplified further. The actual
solution is a new DAG building algorithm that I have coming in a
followup PR. With that PR, there will be no need for the retry queue, as
meshlets will rarely ever get stuck (I checked, the code never gets
called). I split this off into it's own PR for easier reviewing.
Meshlet IDs during building are back to being relative to the overall
list of meshlets across all LODs, instead of starting at 0 for the first
meshlet in the simplification queue for the current LOD, regardless of
how many meshlets there are in the asset total.
Not going to bother to regenerate the bunny asset for this PR.
Currently, `check_visibility` is parameterized over a query filter that
specifies the type of potentially-visible object. This has the
unfortunate side effect that we need a separate system,
`mark_view_visibility_as_changed_if_necessary`, to trigger view
visibility change detection. That system is quite slow because it must
iterate sequentially over all entities in the scene.
This PR moves the query filter from `check_visibility` to a new
component, `VisibilityClass`. `VisibilityClass` stores a list of type
IDs, each corresponding to one of the query filters we used to use.
Because `check_visibility` is no longer specialized to the query filter
at the type level, Bevy now only needs to invoke it once, leading to
better performance as `check_visibility` can do change detection on the
fly rather than delegating it to a separate system.
This commit also has ergonomic improvements, as there's no need for
applications that want to add their own custom renderable components to
add specializations of the `check_visibility` system to the schedule.
Instead, they only need to ensure that the `ViewVisibility` component is
properly kept up to date. The recommended way to do this, and the way
that's demonstrated in the `custom_phase_item` and
`specialized_mesh_pipeline` examples, is to make `ViewVisibility` a
required component and to add the type ID to it in a component add hook.
This patch does this for `Mesh3d`, `Mesh2d`, `Sprite`, `Light`, and
`Node`, which means that most app code doesn't need to change at all.
Note that, although this patch has a large impact on the performance of
visibility determination, it doesn't actually improve the end-to-end
frame time of `many_cubes`. That's because the render world was already
effectively hiding the latency from
`mark_view_visibility_as_changed_if_necessary`. This patch is, however,
necessary for *further* improvements to `many_cubes` performance.
`many_cubes` trace before:

`many_cubes` trace after:

## Migration Guide
* `check_visibility` no longer takes a `QueryFilter`, and there's no
need to add it manually to your app schedule anymore for custom
rendering items. Instead, entities with custom renderable components
should add the appropriate type IDs to `VisibilityClass`. See
`custom_phase_item` for an example.
Updating dependencies; adopted version of #15696. (Supercedes #15696.)
Long answer: hashbrown is no longer using ahash by default, meaning that
we can't use the default-hasher methods with ahasher. So, we have to use
the longer-winded versions instead. This takes the opportunity to also
switch our default hasher as well, but without actually enabling the
default-hasher feature for hashbrown, meaning that we'll be able to
change our hasher more easily at the cost of all of these method calls
being obnoxious forever.
One large change from 0.15 is that `insert_unique_unchecked` is now
`unsafe`, and for cases where unsafe code was denied at the crate level,
I replaced it with `insert`.
## Migration Guide
`bevy_utils` has updated its version of `hashbrown` to 0.15 and now
defaults to `foldhash` instead of `ahash`. This means that if you've
hard-coded your hasher to `bevy_utils::AHasher` or separately used the
`ahash` crate in your code, you may need to switch to `foldhash` to
ensure that everything works like it does in Bevy.
This commit makes skinned meshes batchable on platforms other than WebGL
2. On supported platforms, it replaces the two uniform buffers used for
joint matrices with a pair of storage buffers containing all matrices
for all skinned meshes packed together. The indices into the buffer are
stored in the mesh uniform and mesh input uniform. The GPU mesh
preprocessing step copies the indices in if that step is enabled.
On the `many_foxes` demo, I observed a frame time decrease from 15.470ms
to 11.935ms. This is the result of reducing the `submit_graph_commands`
time from an average of 5.45ms to 0.489ms, an 11x speedup in that
portion of rendering.

This is what the profile looks like for `many_foxes` after these
changes.

---------
Co-authored-by: François Mockers <mockersf@gmail.com>
# Objective
- Remove `derive_more`'s error derivation and replace it with
`thiserror`
## Solution
- Added `derive_more`'s `error` feature to `deny.toml` to prevent it
sneaking back in.
- Reverted to `thiserror` error derivation
## Notes
Merge conflicts were too numerous to revert the individual changes, so
this reversion was done manually. Please scrutinise carefully during
review.
# Objective
Make documentation of a component's required components more visible by
moving it to the type's docs
## Solution
Change `#[require]` from a derive macro helper to an attribute macro.
Disadvantages:
- this silences any unused code warnings on the component, as it is used
by the macro!
- need to import `require` if not using the ecs prelude (I have not
included this in the migration guilde as Rust tooling already suggests
the fix)
---
## Showcase

---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: JMS55 <47158642+JMS55@users.noreply.github.com>
This patch adds the infrastructure necessary for Bevy to support
*bindless resources*, by adding a new `#[bindless]` attribute to
`AsBindGroup`.
Classically, only a single texture (or sampler, or buffer) can be
attached to each shader binding. This means that switching materials
requires breaking a batch and issuing a new drawcall, even if the mesh
is otherwise identical. This adds significant overhead not only in the
driver but also in `wgpu`, as switching bind groups increases the amount
of validation work that `wgpu` must do.
*Bindless resources* are the typical solution to this problem. Instead
of switching bindings between each texture, the renderer instead
supplies a large *array* of all textures in the scene up front, and the
material contains an index into that array. This pattern is repeated for
buffers and samplers as well. The renderer now no longer needs to switch
binding descriptor sets while drawing the scene.
Unfortunately, as things currently stand, this approach won't quite work
for Bevy. Two aspects of `wgpu` conspire to make this ideal approach
unacceptably slow:
1. In the DX12 backend, all binding arrays (bindless resources) must
have a constant size declared in the shader, and all textures in an
array must be bound to actual textures. Changing the size requires a
recompile.
2. Changing even one texture incurs revalidation of all textures, a
process that takes time that's linear in the total size of the binding
array.
This means that declaring a large array of textures big enough to
encompass the entire scene is presently unacceptably slow. For example,
if you declare 4096 textures, then `wgpu` will have to revalidate all
4096 textures if even a single one changes. This process can take
multiple frames.
To work around this problem, this PR groups bindless resources into
small *slabs* and maintains a free list for each. The size of each slab
for the bindless arrays associated with a material is specified via the
`#[bindless(N)]` attribute. For instance, consider the following
declaration:
```rust
#[derive(AsBindGroup)]
#[bindless(16)]
struct MyMaterial {
#[buffer(0)]
color: Vec4,
#[texture(1)]
#[sampler(2)]
diffuse: Handle<Image>,
}
```
The `#[bindless(N)]` attribute specifies that, if bindless arrays are
supported on the current platform, each resource becomes a binding array
of N instances of that resource. So, for `MyMaterial` above, the `color`
attribute is exposed to the shader as `binding_array<vec4<f32>, 16>`,
the `diffuse` texture is exposed to the shader as
`binding_array<texture_2d<f32>, 16>`, and the `diffuse` sampler is
exposed to the shader as `binding_array<sampler, 16>`. Inside the
material's vertex and fragment shaders, the applicable index is
available via the `material_bind_group_slot` field of the `Mesh`
structure. So, for instance, you can access the current color like so:
```wgsl
// `uniform` binding arrays are a non-sequitur, so `uniform` is automatically promoted
// to `storage` in bindless mode.
@group(2) @binding(0) var<storage> material_color: binding_array<Color, 4>;
...
@fragment
fn fragment(in: VertexOutput) -> @location(0) vec4<f32> {
let color = material_color[mesh[in.instance_index].material_bind_group_slot];
...
}
```
Note that portable shader code can't guarantee that the current platform
supports bindless textures. Indeed, bindless mode is only available in
Vulkan and DX12. The `BINDLESS` shader definition is available for your
use to determine whether you're on a bindless platform or not. Thus a
portable version of the shader above would look like:
```wgsl
#ifdef BINDLESS
@group(2) @binding(0) var<storage> material_color: binding_array<Color, 4>;
#else // BINDLESS
@group(2) @binding(0) var<uniform> material_color: Color;
#endif // BINDLESS
...
@fragment
fn fragment(in: VertexOutput) -> @location(0) vec4<f32> {
#ifdef BINDLESS
let color = material_color[mesh[in.instance_index].material_bind_group_slot];
#else // BINDLESS
let color = material_color;
#endif // BINDLESS
...
}
```
Importantly, this PR *doesn't* update `StandardMaterial` to be bindless.
So, for example, `scene_viewer` will currently not run any faster. I
intend to update `StandardMaterial` to use bindless mode in a follow-up
patch.
A new example, `shaders/shader_material_bindless`, has been added to
demonstrate how to use this new feature.
Here's a Tracy profile of `submit_graph_commands` of this patch and an
additional patch (not submitted yet) that makes `StandardMaterial` use
bindless. Red is those patches; yellow is `main`. The scene was Bistro
Exterior with a hack that forces all textures to opaque. You can see a
1.47x mean speedup.

## Migration Guide
* `RenderAssets::prepare_asset` now takes an `AssetId` parameter.
* Bin keys now have Bevy-specific material bind group indices instead of
`wgpu` material bind group IDs, as part of the bindless change. Use the
new `MaterialBindGroupAllocator` to map from bind group index to bind
group ID.
# Objective
- Fixes#16078
## Solution
- Rename things to clarify that we _want_ unclipped depth for
directional light shadow views, and need some way of disabling the GPU's
builtin depth clipping
- Use DEPTH_CLIP_CONTROL instead of the fragment shader emulation on
supported platforms
- Pass only the clip position depth instead of the whole clip position
between vertex->fragment shader (no idea if this helps performance or
not, compiler might optimize it anyways)
- Meshlets
- HW raster always uses DEPTH_CLIP_CONTROL since it targets a more
limited set of platforms
- SW raster was not handling DEPTH_CLAMP_ORTHO correctly, it ended up
pretty much doing nothing.
- This PR made me realize that SW raster technically should have depth
clipping for all views that are not directional light shadows, but I
decided not to bother writing it. I'm not sure that it ever matters in
practice. If proven otherwise, I can add it.
## Testing
- Did you test these changes? If so, how?
- Lighting example. Both opaque (no fragment shader) and alpha masked
geometry (fragment shader emulation) are working with
depth_clip_control, and both work when it's turned off. Also tested
meshlet example.
- Are there any parts that need more testing?
- Performance. I can't figure out a good test scene.
- How can other people (reviewers) test your changes? Is there anything
specific they need to know?
- Toggle depth_clip_control_supported in prepass/mod.rs line 323 to turn
this PR on or off.
- If relevant, what platforms did you test these changes on, and are
there any important ones you can't test?
- Native
---
## Migration Guide
- `MeshPipelineKey::DEPTH_CLAMP_ORTHO` is now
`MeshPipelineKey::UNCLIPPED_DEPTH_ORTHO`
- The `DEPTH_CLAMP_ORTHO` shaderdef has been renamed to
`UNCLIPPED_DEPTH_ORTHO_EMULATION`
- `clip_position_unclamped: vec4<f32>` is now `unclipped_depth: f32`
I didn't mean to make this item private, fixing it for the 0.15 release
to be consistent with 0.14.
(maintainers: please make sure this gets merged into the 0.15 release
branch as well as main)
# Objective
- wgpu 0.20 made workgroup vars stop being zero-init by default. this
broke some applications (cough foresight cough) and now we workaround
it. wgpu exposes a compilation option that zero initializes workgroup
memory by default, but bevy does not expose it.
## Solution
- expose the compilation option wgpu gives us
## Testing
- ran examples: 3d_scene, compute_shader_game_of_life, gpu_readback,
lines, specialized_mesh_pipeline. they all work
- confirmed fix for our own problems
---
</details>
## Migration Guide
- add `zero_initialize_workgroup_memory: false,` to
`ComputePipelineDescriptor` or `RenderPipelineDescriptor` structs to
preserve 0.14 functionality, add `zero_initialize_workgroup_memory:
true,` to restore bevy 0.13 functionality.
# Objective
- Choose LOD based on normal simplification error in addition to
position error
- Update meshoptimizer to 0.22, which has a bunch of simplifier
improvements
## Testing
- Did you test these changes? If so, how?
- Visualize normals, and compare LOD changes before and after. Normals
no longer visibly change as the LOD cut changes.
- Are there any parts that need more testing?
- No
- How can other people (reviewers) test your changes? Is there anything
specific they need to know?
- Run the meshlet example in this PR and on main and move around to
change the LOD cut. Before running each example, in
meshlet_mesh_material.wgsl, replace `let color = vec3(rand_f(&rng),
rand_f(&rng), rand_f(&rng));` with `let color =
(vertex_output.world_normal + 1.0) / 2.0;`. Make sure to download the
appropriate bunny asset for each branch!
# Objective
- Make the meshlet fill cluster buffers pass slightly faster
- Address https://github.com/bevyengine/bevy/issues/15920 for meshlets
- Added PreviousGlobalTransform as a required meshlet component to avoid
extra archetype moves, slightly alleviating
https://github.com/bevyengine/bevy/issues/14681 for meshlets
- Enforce that MeshletPlugin::cluster_buffer_slots is not greater than
2^25 (glitches will occur otherwise). Technically this field controls
post-lod/culling cluster count, and the issue is on pre-lod/culling
cluster count, but it's still valid now, and in the future this will be
more true.
Needs to be merged after https://github.com/bevyengine/bevy/pull/15846
and https://github.com/bevyengine/bevy/pull/15886
## Solution
- Old pass dispatched a thread per cluster, and did a binary search over
the instances to find which instance the cluster belongs to, and what
meshlet index within the instance it is.
- New pass dispatches a workgroup per instance, and has the workgroup
loop over all meshlets in the instance in order to write out the cluster
data.
- Use a push constant instead of arrayLength to fix the linked bug
- Remap 1d->2d dispatch for software raster only if actually needed to
save on spawning excess workgroups
## Testing
- Did you test these changes? If so, how?
- Ran the meshlet example, and an example with 1041 instances of 32217
meshlets per instance. Profiled the second scene with nsight, went from
0.55ms -> 0.40ms. Small savings. We're pretty much VRAM bandwidth bound
at this point.
- How can other people (reviewers) test your changes? Is there anything
specific they need to know?
- Run the meshlet example
## Changelog (non-meshlets)
- PreviousGlobalTransform now implements the Default trait
Take a bunch more improvements from @zeux's nanite.cpp code.
* Use position-only vertices (discard other attributes) to determine
meshlet connectivity for grouping
* Rather than using the lock borders flag when simplifying meshlet
groups, provide the locked vertices ourselves. The lock borders flag
locks the entire border of the meshlet group, but really we only want to
lock the edges between meshlet groups - outwards facing edges are fine
to unlock. This gives a really significant increase to the DAG quality.
* Add back stuck meshlets (group has only a single meshlet,
simplification failed) to the simplification queue to allow them to get
used later on and have another attempt at simplifying
* Target 8 meshlets per group instead of 4 (second biggest improvement
after manual locks)
* Provide a seed to metis for deterministic meshlet building
* Misc other improvements
We can remove the usage of unsafe after the next upstream meshopt
release, but for now we need to use the ffi function directly. I'll do
another round of improvements later, mainly attribute-aware
simplification and using spatial weights for meshlet grouping.
Need to merge https://github.com/bevyengine/bevy/pull/15846 first.
# Objective
1. Prevent weird glitches with stray pixels scattered around the scene

2. Prevent weird glitchy full-screen triangles that pop-up and destroy
perf (SW rasterizing huge triangles is slow)

## Solution
1. Use floating point math in the SW rasterizer bounding box calculation
to handle negative verticss, and add backface culling
2. Force hardware raster for clusters that clip the near plane, and let
the hardware rasterizer handle the clipping
I also adjusted the SW rasterizer threshold to < 64 pixels (little bit
better perf in my test scene, but still need to do a more comprehensive
test), and enabled backface culling for the hardware raster pipeline.
## Testing
- Did you test these changes? If so, how?
- Yes, on an example scene. Issues no longer occur.
- Are there any parts that need more testing?
- No.
- How can other people (reviewers) test your changes? Is there anything
specific they need to know?
- Run the meshlet example.
# Objective
In the Render World, there are a number of collections that are derived
from Main World entities and are used to drive rendering. The most
notable are:
- `VisibleEntities`, which is generated in the `check_visibility` system
and contains visible entities for a view.
- `ExtractedInstances`, which maps entity ids to asset ids.
In the old model, these collections were trivially kept in sync -- any
extracted phase item could look itself up because the render entity id
was guaranteed to always match the corresponding main world id.
After #15320, this became much more complicated, and was leading to a
number of subtle bugs in the Render World. The main rendering systems,
i.e. `queue_material_meshes` and `queue_material2d_meshes`, follow a
similar pattern:
```rust
for visible_entity in visible_entities.iter::<With<Mesh2d>>() {
let Some(mesh_instance) = render_mesh_instances.get_mut(visible_entity) else {
continue;
};
// Look some more stuff up and specialize the pipeline...
let bin_key = Opaque2dBinKey {
pipeline: pipeline_id,
draw_function: draw_opaque_2d,
asset_id: mesh_instance.mesh_asset_id.into(),
material_bind_group_id: material_2d.get_bind_group_id().0,
};
opaque_phase.add(
bin_key,
*visible_entity,
BinnedRenderPhaseType::mesh(mesh_instance.automatic_batching),
);
}
```
In this case, `visible_entities` and `render_mesh_instances` are both
collections that are created and keyed by Main World entity ids, and so
this lookup happens to work by coincidence. However, there is a major
unintentional bug here: namely, because `visible_entities` is a
collection of Main World ids, the phase item being queued is created
with a Main World id rather than its correct Render World id.
This happens to not break mesh rendering because the render commands
used for drawing meshes do not access the `ItemQuery` parameter, but
demonstrates the confusion that is now possible: our UI phase items are
correctly being queued with Render World ids while our meshes aren't.
Additionally, this makes it very easy and error prone to use the wrong
entity id to look up things like assets. For example, if instead we
ignored visibility checks and queued our meshes via a query, we'd have
to be extra careful to use `&MainEntity` instead of the natural
`Entity`.
## Solution
Make all collections that are derived from Main World data use
`MainEntity` as their key, to ensure type safety and avoid accidentally
looking up data with the wrong entity id:
```rust
pub type MainEntityHashMap<V> = hashbrown::HashMap<MainEntity, V, EntityHash>;
```
Additionally, we make all `PhaseItem` be able to provide both their Main
and Render World ids, to allow render phase implementors maximum
flexibility as to what id should be used to look up data.
You can think of this like tracking at the type level whether something
in the Render World should use it's "primary key", i.e. entity id, or
needs to use a foreign key, i.e. `MainEntity`.
## Testing
##### TODO:
This will require extensive testing to make sure things didn't break!
Additionally, some extraction logic has become more complicated and
needs to be checked for regressions.
## Migration Guide
With the advent of the retained render world, collections that contain
references to `Entity` that are extracted into the render world have
been changed to contain `MainEntity` in order to prevent errors where a
render world entity id is used to look up an item by accident. Custom
rendering code may need to be changed to query for `&MainEntity` in
order to look up the correct item from such a collection. Additionally,
users who implement their own extraction logic for collections of main
world entity should strongly consider extracting into a different
collection that uses `MainEntity` as a key.
Additionally, render phases now require specifying both the `Entity` and
`MainEntity` for a given `PhaseItem`. Custom render phases should ensure
`MainEntity` is available when queuing a phase item.
# Objective
- Closes#15716
- Closes#15718
## Solution
- Replace `Handle<MeshletMesh>` with a new `MeshletMesh3d` component
- As expected there were some random things that needed fixing:
- A couple tests were storing handles just to prevent them from being
dropped I believe, which seems to have been unnecessary in some.
- The `SpriteBundle` still had a `Handle<Image>` field. I've removed
this.
- Tests in `bevy_sprite` incorrectly added a `Handle<Image>` field
outside of the `Sprite` component.
- A few examples were still inserting `Handle`s, switched those to their
corresponding wrappers.
- 2 examples that were still querying for `Handle<Image>` were changed
to query `Sprite`
## Testing
- I've verified that the changed example work now
## Migration Guide
`Handle` can no longer be used as a `Component`. All existing Bevy types
using this pattern have been wrapped in their own semantically
meaningful type. You should do the same for any custom `Handle`
components your project needs.
The `Handle<MeshletMesh>` component is now `MeshletMesh3d`.
The `WithMeshletMesh` type alias has been removed. Use
`With<MeshletMesh3d>` instead.
# Objective
- Prepare for streaming by storing vertex data per-meshlet, rather than
per-mesh (this means duplicating vertices per-meshlet)
- Compress vertex data to reduce the cost of this
## Solution
The important parts are in from_mesh.rs, the changes to the Meshlet type
in asset.rs, and the changes in meshlet_bindings.wgsl. Everything else
is pretty secondary/boilerplate/straightforward changes.
- Positions are quantized in centimeters with a user-provided power of 2
factor (ideally auto-determined, but that's a TODO for the future),
encoded as an offset relative to the minimum value within the meshlet,
and then stored as a packed list of bits using the minimum number of
bits needed for each vertex position channel for that meshlet
- E.g. quantize positions (lossly, throws away precision that's not
needed leading to using less bits in the bitstream encoding)
- Get the min/max quantized value of each X/Y/Z channel of the quantized
positions within a meshlet
- Encode values relative to the min value of the meshlet. E.g. convert
from [min, max] to [0, max - min]
- The new max value in the meshlet is (max - min), which only takes N
bits, so we only need N bits to store each channel within the meshlet
(lossless)
- We can store the min value and that it takes N bits per channel in the
meshlet metadata, and reconstruct the position from the bitstream
- Normals are octahedral encoded and than snorm2x16 packed and stored as
a single u32.
- Would be better to implement the precise variant of octhedral encoding
for extra precision (no extra decode cost), but decided to keep it
simple for now and leave that as a followup
- Tried doing a quantizing and bitstream encoding scheme like I did for
positions, but struggled to get it smaller. Decided to go with this for
simplicity for now
- UVs are uncompressed and take a full 64bits per vertex which is
expensive
- In the future this should be improved
- Tangents, as of the previous PR, are not explicitly stored and are
instead derived from screen space gradients
- While I'm here, split up MeshletMeshSaverLoader into two separate
types
Other future changes include implementing a smaller encoding of triangle
data (3 u8 indices = 24 bits per triangle currently), and more
disk-oriented compression schemes.
References:
* "A Deep Dive into UE5's Nanite Virtualized Geometry"
https://advances.realtimerendering.com/s2021/Karis_Nanite_SIGGRAPH_Advances_2021_final.pdf#page=128
(also available on youtube)
* "Towards Practical Meshlet Compression"
https://arxiv.org/pdf/2404.06359
* "Vertex quantization in Omniforce Game Engine"
https://daniilvinn.github.io/2024/05/04/omniforce-vertex-quantization.html
## Testing
- Did you test these changes? If so, how?
- Converted the stanford bunny, and rendered it with a debug material
showing normals, and confirmed that it's identical to what's on main.
EDIT: See additional testing in the comments below.
- Are there any parts that need more testing?
- Could use some more size comparisons on various meshes, and testing
different quantization factors. Not sure if 4 is a good default. EDIT:
See additional testing in the comments below.
- Also did not test runtime performance of the shaders. EDIT: See
additional testing in the comments below.
- How can other people (reviewers) test your changes? Is there anything
specific they need to know?
- Use my unholy script, replacing the meshlet example
https://paste.rs/7xQHk.rs (must make MeshletMesh fields pub instead of
pub crate, must add lz4_flex as a dev-dependency) (must compile with
meshlet and meshlet_processor features, mesh must have only positions,
normals, and UVs, no vertex colors or tangents)
---
## Migration Guide
- TBD by JMS55 at the end of the release
# Objective
- First step towards #15558
## Solution
- Rename `get_vertex_buffer_data` to `create_packed_vertex_buffer_data`
to make it clear that it is not "free" and actually allocates
- Compute length analytically for preallocation instead of creating the
buffer to get its length and immediately discard it
- Use existing vertex attribute size calculation method to reduce code
duplication
- Fix a bug where mesh index data was being replaced by unnecessarily
newly created mesh vertex data in some cases
- Overall reduces mesh copies by two. We still have plenty to go, but
these were the easy ones.
## Testing
- I ran 3d_scene, lighting, and many_cubes, they look fine.
- Benchmarks would be nice, but this is very obviously a win in perf and
correctness.
---
## Migration Guide
- `Mesh::create_packed_vertex_buffer_data` has been renamed
`Mesh::create_packed_vertex_buffer_data` to reflect the fact that it
copies data and allocates.
## Showcase
- look mom, less copies
# Objective
Fixes#15541
A bunch of lifetimes were added during the Assets V2 rework, but after
moving to async traits in #12550 they can be elided. That PR mentions
that this might be the case, but apparently it wasn't followed up on at
the time.
~~I ended up grepping for `<'a` and finding a similar case in
`bevy_reflect` which I also fixed.~~ (edit: that one was needed
apparently)
Note that elided lifetimes are unstable in `impl Trait`. If that gets
stabilized then we can elide even more.
## Solution
Remove the extra lifetimes.
## Testing
Everything still compiles. If I have messed something up there is a
small risk that some user code stops compiling, but all the examples
still work at least.
---
## Migration Guide
The traits `AssetLoader`, `AssetSaver` and `Process` traits from
`bevy_asset` now use elided lifetimes. If you implement these then
remove the named lifetime.
- Adopted from #14449
- Still fixes#12144.
## Migration Guide
The retained render world is a complex change: migrating might take one
of a few different forms depending on the patterns you're using.
For every example, we specify in which world the code is run. Most of
the changes affect render world code, so for the average Bevy user who's
using Bevy's high-level rendering APIs, these changes are unlikely to
affect your code.
### Spawning entities in the render world
Previously, if you spawned an entity with `world.spawn(...)`,
`commands.spawn(...)` or some other method in the rendering world, it
would be despawned at the end of each frame. In 0.15, this is no longer
the case and so your old code could leak entities. This can be mitigated
by either re-architecting your code to no longer continuously spawn
entities (like you're used to in the main world), or by adding the
`bevy_render::world_sync::TemporaryRenderEntity` component to the entity
you're spawning. Entities tagged with `TemporaryRenderEntity` will be
removed at the end of each frame (like before).
### Extract components with `ExtractComponentPlugin`
```
// main world
app.add_plugins(ExtractComponentPlugin::<ComponentToExtract>::default());
```
`ExtractComponentPlugin` has been changed to only work with synced
entities. Entities are automatically synced if `ComponentToExtract` is
added to them. However, entities are not "unsynced" if any given
`ComponentToExtract` is removed, because an entity may have multiple
components to extract. This would cause the other components to no
longer get extracted because the entity is not synced.
So be careful when only removing extracted components from entities in
the render world, because it might leave an entity behind in the render
world. The solution here is to avoid only removing extracted components
and instead despawn the entire entity.
### Manual extraction using `Extract<Query<(Entity, ...)>>`
```rust
// in render world, inspired by bevy_pbr/src/cluster/mod.rs
pub fn extract_clusters(
mut commands: Commands,
views: Extract<Query<(Entity, &Clusters, &Camera)>>,
) {
for (entity, clusters, camera) in &views {
// some code
commands.get_or_spawn(entity).insert(...);
}
}
```
One of the primary consequences of the retained rendering world is that
there's no longer a one-to-one mapping from entity IDs in the main world
to entity IDs in the render world. Unlike in Bevy 0.14, Entity 42 in the
main world doesn't necessarily map to entity 42 in the render world.
Previous code which called `get_or_spawn(main_world_entity)` in the
render world (`Extract<Query<(Entity, ...)>>` returns main world
entities). Instead, you should use `&RenderEntity` and
`render_entity.id()` to get the correct entity in the render world. Note
that this entity does need to be synced first in order to have a
`RenderEntity`.
When performing manual abstraction, this won't happen automatically
(like with `ExtractComponentPlugin`) so add a `SyncToRenderWorld` marker
component to the entities you want to extract.
This results in the following code:
```rust
// in render world, inspired by bevy_pbr/src/cluster/mod.rs
pub fn extract_clusters(
mut commands: Commands,
views: Extract<Query<(&RenderEntity, &Clusters, &Camera)>>,
) {
for (render_entity, clusters, camera) in &views {
// some code
commands.get_or_spawn(render_entity.id()).insert(...);
}
}
// in main world, when spawning
world.spawn(Clusters::default(), Camera::default(), SyncToRenderWorld)
```
### Looking up `Entity` ids in the render world
As previously stated, there's now no correspondence between main world
and render world `Entity` identifiers.
Querying for `Entity` in the render world will return the `Entity` id in
the render world: query for `MainEntity` (and use its `id()` method) to
get the corresponding entity in the main world.
This is also a good way to tell the difference between synced and
unsynced entities in the render world, because unsynced entities won't
have a `MainEntity` component.
---------
Co-authored-by: re0312 <re0312@outlook.com>
Co-authored-by: re0312 <45868716+re0312@users.noreply.github.com>
Co-authored-by: Periwink <charlesbour@gmail.com>
Co-authored-by: Anselmo Sampietro <ans.samp@gmail.com>
Co-authored-by: Emerson Coskey <56370779+ecoskey@users.noreply.github.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Christian Hughes <9044780+ItsDoot@users.noreply.github.com>
* Save 16 bytes per vertex by calculating tangents in the shader at
runtime, rather than storing them in the vertex data.
* Based on https://jcgt.org/published/0009/03/04,
https://www.jeremyong.com/graphics/2023/12/16/surface-gradient-bump-mapping.
* Fixed visbuffer resolve to use the updated algorithm that flips ddy
correctly
* Added some more docs about meshlet material limitations, and some
TODOs about transforming UV coordinates for the future.

For testing add a normal map to the bunnies with StandardMaterial like
below, and then test that on both main and this PR (make sure to
download the correct bunny for each). Results should be mostly
identical.
```rust
normal_map_texture: Some(asset_server.load_with_settings(
"textures/BlueNoise-Normal.png",
|settings: &mut ImageLoaderSettings| settings.is_srgb = false,
)),
```
# Objective
- Fixes#6370
- Closes#6581
## Solution
- Added the following lints to the workspace:
- `std_instead_of_core`
- `std_instead_of_alloc`
- `alloc_instead_of_core`
- Used `cargo +nightly fmt` with [item level use
formatting](https://rust-lang.github.io/rustfmt/?version=v1.6.0&search=#Item%5C%3A)
to split all `use` statements into single items.
- Used `cargo clippy --workspace --all-targets --all-features --fix
--allow-dirty` to _attempt_ to resolve the new linting issues, and
intervened where the lint was unable to resolve the issue automatically
(usually due to needing an `extern crate alloc;` statement in a crate
root).
- Manually removed certain uses of `std` where negative feature gating
prevented `--all-features` from finding the offending uses.
- Used `cargo +nightly fmt` with [crate level use
formatting](https://rust-lang.github.io/rustfmt/?version=v1.6.0&search=#Crate%5C%3A)
to re-merge all `use` statements matching Bevy's previous styling.
- Manually fixed cases where the `fmt` tool could not re-merge `use`
statements due to conditional compilation attributes.
## Testing
- Ran CI locally
## Migration Guide
The MSRV is now 1.81. Please update to this version or higher.
## Notes
- This is a _massive_ change to try and push through, which is why I've
outlined the semi-automatic steps I used to create this PR, in case this
fails and someone else tries again in the future.
- Making this change has no impact on user code, but does mean Bevy
contributors will be warned to use `core` and `alloc` instead of `std`
where possible.
- This lint is a critical first step towards investigating `no_std`
options for Bevy.
---------
Co-authored-by: François Mockers <francois.mockers@vleue.com>