bevy/examples/shader/texture_binding_array.rs
Carter Anderson 17edf4f7c7
Copy on Write AssetPaths (#9729)
# Objective

The `AssetServer` and `AssetProcessor` do a lot of `AssetPath` cloning
(across many threads). To store the path on the handle, to store paths
in dependency lists, to pass an owned path to the offloaded thread, to
pass a path to the LoadContext, etc , etc. Cloning multiple string
allocations multiple times like this will add up. It is worth optimizing
this.

Referenced in #9714 

## Solution

Added a new `CowArc<T>` type to `bevy_util`, which behaves a lot like
`Cow<T>`, but the Owned variant is an `Arc<T>`. Use this in place of
`Cow<str>` and `Cow<Path>` on `AssetPath`.

---

## Changelog

- `AssetPath` now internally uses `CowArc`, making clone operations much
cheaper
- `AssetPath` now serializes as `AssetPath("some_path.extension#Label")`
instead of as `AssetPath { path: "some_path.extension", label:
Some("Label) }`


## Migration Guide

```rust
// Old
AssetPath::new("logo.png", None);

// New
AssetPath::new("logo.png");

// Old
AssetPath::new("scene.gltf", Some("Mesh0");

// New
AssetPath::new("scene.gltf").with_label("Mesh0");
```

`AssetPath` now serializes as `AssetPath("some_path.extension#Label")`
instead of as `AssetPath { path: "some_path.extension", label:
Some("Label) }`

---------

Co-authored-by: Pascal Hertleif <killercup@gmail.com>
2023-09-09 23:15:10 +00:00

181 lines
5.9 KiB
Rust

//! A shader that binds several textures onto one
//! `binding_array<texture<f32>>` shader binding slot and sample non-uniformly.
use bevy::{
prelude::*,
reflect::TypePath,
render::{
render_asset::RenderAssets,
render_resource::{AsBindGroupError, PreparedBindGroup, *},
renderer::RenderDevice,
texture::FallbackImage,
RenderApp,
},
};
use std::{num::NonZeroU32, process::exit};
fn main() {
let mut app = App::new();
app.add_plugins((
DefaultPlugins.set(ImagePlugin::default_nearest()),
GpuFeatureSupportChecker,
MaterialPlugin::<BindlessMaterial>::default(),
))
.add_systems(Startup, setup)
.run();
}
const MAX_TEXTURE_COUNT: usize = 16;
const TILE_ID: [usize; 16] = [
19, 23, 4, 33, 12, 69, 30, 48, 10, 65, 40, 47, 57, 41, 44, 46,
];
struct GpuFeatureSupportChecker;
impl Plugin for GpuFeatureSupportChecker {
fn build(&self, _app: &mut App) {}
fn finish(&self, app: &mut App) {
let Ok(render_app) = app.get_sub_app_mut(RenderApp) else {
return;
};
let render_device = render_app.world.resource::<RenderDevice>();
// Check if the device support the required feature. If not, exit the example.
// In a real application, you should setup a fallback for the missing feature
if !render_device
.features()
.contains(WgpuFeatures::SAMPLED_TEXTURE_AND_STORAGE_BUFFER_ARRAY_NON_UNIFORM_INDEXING)
{
error!(
"Render device doesn't support feature \
SAMPLED_TEXTURE_AND_STORAGE_BUFFER_ARRAY_NON_UNIFORM_INDEXING, \
which is required for texture binding arrays"
);
exit(1);
}
}
}
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<BindlessMaterial>>,
asset_server: Res<AssetServer>,
) {
commands.spawn(Camera3dBundle {
transform: Transform::from_xyz(2.0, 2.0, 2.0).looking_at(Vec3::new(0.0, 0.0, 0.0), Vec3::Y),
..Default::default()
});
// load 16 textures
let textures: Vec<_> = TILE_ID
.iter()
.map(|id| asset_server.load(format!("textures/rpg/tiles/generic-rpg-tile{id:0>2}.png")))
.collect();
// a cube with multiple textures
commands.spawn(MaterialMeshBundle {
mesh: meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
material: materials.add(BindlessMaterial { textures }),
..Default::default()
});
}
#[derive(Asset, TypePath, Debug, Clone)]
struct BindlessMaterial {
textures: Vec<Handle<Image>>,
}
impl AsBindGroup for BindlessMaterial {
type Data = ();
fn as_bind_group(
&self,
layout: &BindGroupLayout,
render_device: &RenderDevice,
image_assets: &RenderAssets<Image>,
fallback_image: &FallbackImage,
) -> Result<PreparedBindGroup<Self::Data>, AsBindGroupError> {
// retrieve the render resources from handles
let mut images = vec![];
for handle in self.textures.iter().take(MAX_TEXTURE_COUNT) {
match image_assets.get(handle) {
Some(image) => images.push(image),
None => return Err(AsBindGroupError::RetryNextUpdate),
}
}
let fallback_image = &fallback_image.d2;
let textures = vec![&fallback_image.texture_view; MAX_TEXTURE_COUNT];
// convert bevy's resource types to WGPU's references
let mut textures: Vec<_> = textures.into_iter().map(|texture| &**texture).collect();
// fill in up to the first `MAX_TEXTURE_COUNT` textures and samplers to the arrays
for (id, image) in images.into_iter().enumerate() {
textures[id] = &*image.texture_view;
}
let bind_group = render_device.create_bind_group(&BindGroupDescriptor {
label: "bindless_material_bind_group".into(),
layout,
entries: &[
BindGroupEntry {
binding: 0,
resource: BindingResource::TextureViewArray(&textures[..]),
},
BindGroupEntry {
binding: 1,
resource: BindingResource::Sampler(&fallback_image.sampler),
},
],
});
Ok(PreparedBindGroup {
bindings: vec![],
bind_group,
data: (),
})
}
fn bind_group_layout(render_device: &RenderDevice) -> BindGroupLayout
where
Self: Sized,
{
render_device.create_bind_group_layout(&BindGroupLayoutDescriptor {
label: "bindless_material_layout".into(),
entries: &[
// @group(1) @binding(0) var textures: binding_array<texture_2d<f32>>;
BindGroupLayoutEntry {
binding: 0,
visibility: ShaderStages::FRAGMENT,
ty: BindingType::Texture {
sample_type: TextureSampleType::Float { filterable: true },
view_dimension: TextureViewDimension::D2,
multisampled: false,
},
count: NonZeroU32::new(MAX_TEXTURE_COUNT as u32),
},
// @group(1) @binding(1) var nearest_sampler: sampler;
BindGroupLayoutEntry {
binding: 1,
visibility: ShaderStages::FRAGMENT,
ty: BindingType::Sampler(SamplerBindingType::Filtering),
count: None,
// Note: as textures, multiple samplers can also be bound onto one binding slot.
// One may need to pay attention to the limit of sampler binding amount on some platforms.
// count: NonZeroU32::new(MAX_TEXTURE_COUNT as u32),
},
],
})
}
}
impl Material for BindlessMaterial {
fn fragment_shader() -> ShaderRef {
"shaders/texture_binding_array.wgsl".into()
}
}