# Objective
- bump naga_oil to 0.10
- update shader imports to use rusty syntax
## Migration Guide
naga_oil 0.10 reworks the import mechanism to support more syntax to
make it more rusty, and test for item use before importing to determine
which imports are modules and which are items, which allows:
- use rust-style imports
```
#import bevy_pbr::{
pbr_functions::{alpha_discard as discard, apply_pbr_lighting},
mesh_bindings,
}
```
- import partial paths:
```
#import part::of::path
...
path::remainder::function();
```
which will call to `part::of::path::remainder::function`
- use fully qualified paths without importing:
```
// #import bevy_pbr::pbr_functions
bevy_pbr::pbr_functions::pbr()
```
- use imported items without qualifying
```
#import bevy_pbr::pbr_functions::pbr
// for backwards compatibility the old style is still supported:
// #import bevy_pbr::pbr_functions pbr
...
pbr()
```
- allows most imported items to end with `_` and numbers (naga_oil#30).
still doesn't allow struct members to end with `_` or numbers but it's
progress.
- the vast majority of existing shader code will work without changes,
but will emit "deprecated" warnings for old-style imports. these can be
suppressed with the `allow-deprecated` feature.
- partly breaks overrides (as far as i'm aware nobody uses these yet) -
now overrides will only be applied if the overriding module is added as
an additional import in the arguments to `Composer::make_naga_module` or
`Composer::add_composable_module`. this is necessary to support
determining whether imports are modules or items.
# Objective
operate on naga IR directly to improve handling of shader modules.
- give codespan reporting into imported modules
- allow glsl to be used from wgsl and vice-versa
the ultimate objective is to make it possible to
- provide user hooks for core shader functions (to modify light
behaviour within the standard pbr pipeline, for example)
- make automatic binding slot allocation possible
but ... since this is already big, adds some value and (i think) is at
feature parity with the existing code, i wanted to push this now.
## Solution
i made a crate called naga_oil (https://github.com/robtfm/naga_oil -
unpublished for now, could be part of bevy) which manages modules by
- building each module independantly to naga IR
- creating "header" files for each supported language, which are used to
build dependent modules/shaders
- make final shaders by combining the shader IR with the IR for imported
modules
then integrated this into bevy, replacing some of the existing shader
processing stuff. also reworked examples to reflect this.
## Migration Guide
shaders that don't use `#import` directives should work without changes.
the most notable user-facing difference is that imported
functions/variables/etc need to be qualified at point of use, and
there's no "leakage" of visible stuff into your shader scope from the
imports of your imports, so if you used things imported by your imports,
you now need to import them directly and qualify them.
the current strategy of including/'spreading' `mesh_vertex_output`
directly into a struct doesn't work any more, so these need to be
modified as per the examples (e.g. color_material.wgsl, or many others).
mesh data is assumed to be in bindgroup 2 by default, if mesh data is
bound into bindgroup 1 instead then the shader def `MESH_BINDGROUP_1`
needs to be added to the pipeline shader_defs.
# Objective
- Support WebGPU
- alternative to #5027 that doesn't need any async / await
- fixes#8315
- Surprise fix#7318
## Solution
### For async renderer initialisation
- Update the plugin lifecycle:
- app builds the plugin
- calls `plugin.build`
- registers the plugin
- app starts the event loop
- event loop waits for `ready` of all registered plugins in the same
order
- returns `true` by default
- then call all `finish` then all `cleanup` in the same order as
registered
- then execute the schedule
In the case of the renderer, to avoid anything async:
- building the renderer plugin creates a detached task that will send
back the initialised renderer through a mutex in a resource
- `ready` will wait for the renderer to be present in the resource
- `finish` will take that renderer and place it in the expected
resources by other plugins
- other plugins (that expect the renderer to be available) `finish` are
called and they are able to set up their pipelines
- `cleanup` is called, only custom one is still for pipeline rendering
### For WebGPU support
- update the `build-wasm-example` script to support passing `--api
webgpu` that will build the example with WebGPU support
- feature for webgl2 was always enabled when building for wasm. it's now
in the default feature list and enabled on all platforms, so check for
this feature must also check that the target_arch is `wasm32`
---
## Migration Guide
- `Plugin::setup` has been renamed `Plugin::cleanup`
- `Plugin::finish` has been added, and plugins adding pipelines should
do it in this function instead of `Plugin::build`
```rust
// Before
impl Plugin for MyPlugin {
fn build(&self, app: &mut App) {
app.insert_resource::<MyResource>
.add_systems(Update, my_system);
let render_app = match app.get_sub_app_mut(RenderApp) {
Ok(render_app) => render_app,
Err(_) => return,
};
render_app
.init_resource::<RenderResourceNeedingDevice>()
.init_resource::<OtherRenderResource>();
}
}
// After
impl Plugin for MyPlugin {
fn build(&self, app: &mut App) {
app.insert_resource::<MyResource>
.add_systems(Update, my_system);
let render_app = match app.get_sub_app_mut(RenderApp) {
Ok(render_app) => render_app,
Err(_) => return,
};
render_app
.init_resource::<OtherRenderResource>();
}
fn finish(&self, app: &mut App) {
let render_app = match app.get_sub_app_mut(RenderApp) {
Ok(render_app) => render_app,
Err(_) => return,
};
render_app
.init_resource::<RenderResourceNeedingDevice>();
}
}
```
