bevy/crates/bevy_render/macros/src/lib.rs
charlotte 🌸 e6ba9a6d18
Type erased materials (#19667)
# Objective

Closes #18075

In order to enable a number of patterns for dynamic materials in the
engine, it's necessary to decouple the renderer from the `Material`
trait.

This opens the possibility for:
- Materials that aren't coupled to `AsBindGroup`.
- 2d using the underlying 3d bindless infrastructure.
- Dynamic materials that can change their layout at runtime.
- Materials that aren't even backed by a Rust struct at all.

## Solution

In short, remove all trait bounds from render world material systems and
resources. This means moving a bunch of stuff onto `MaterialProperties`
and engaging in some hacks to make specialization work. Rather than
storing the bind group data in `MaterialBindGroupAllocator`, right now
we're storing it in a closure on `MaterialProperties`. TBD if this has
bad performance characteristics.

## Benchmarks

- `many_cubes`:
`cargo run --example many_cubes --release --features=bevy/trace_tracy --
--vary-material-data-per-instance`:
![Screenshot 2025-06-26
235426](https://github.com/user-attachments/assets/10a0ee29-9932-4f91-ab43-33518b117ac5)

- @DGriffin91's Caldera
`cargo run --release --features=bevy/trace_tracy -- --random-materials`

![image](https://github.com/user-attachments/assets/ef91ba6a-8e88-4922-a73f-acb0af5b0dbc)


- @DGriffin91's Caldera with 20 unique material types (i.e.
`MaterialPlugin<M>`) and random materials per mesh
`cargo run --release --features=bevy/trace_tracy -- --random-materials`
![Screenshot 2025-06-27
000425](https://github.com/user-attachments/assets/9561388b-881d-46cf-8c3d-b15b3e9aedc7)


### TODO

- We almost certainly lost some parallelization from removing the type
params that could be gained back from smarter iteration.
- Test all the things that could have broken.
- ~Fix meshlets~

## Showcase

See [the
example](https://github.com/bevyengine/bevy/pull/19667/files#diff-9d768cfe1c3aa81eff365d250d3cbe5a63e8df63e81dd85f64c3c3cd993f6d94)
for a custom material implemented without the use of the `Material`
trait and thus `AsBindGroup`.


![image](https://github.com/user-attachments/assets/e3fcca7c-e04e-4a4e-9d89-39d697a9e3b8)

---------

Co-authored-by: IceSentry <IceSentry@users.noreply.github.com>
Co-authored-by: IceSentry <c.giguere42@gmail.com>
2025-06-27 22:57:24 +00:00

130 lines
4.0 KiB
Rust

#![expect(missing_docs, reason = "Not all docs are written yet, see #3492.")]
#![cfg_attr(docsrs, feature(doc_auto_cfg))]
mod as_bind_group;
mod extract_component;
mod extract_resource;
use bevy_macro_utils::{derive_label, BevyManifest};
use proc_macro::TokenStream;
use quote::format_ident;
use syn::{parse_macro_input, DeriveInput};
pub(crate) fn bevy_render_path() -> syn::Path {
BevyManifest::shared().get_path("bevy_render")
}
#[proc_macro_derive(ExtractResource)]
pub fn derive_extract_resource(input: TokenStream) -> TokenStream {
extract_resource::derive_extract_resource(input)
}
/// Implements `ExtractComponent` trait for a component.
///
/// The component must implement [`Clone`].
/// The component will be extracted into the render world via cloning.
/// Note that this only enables extraction of the component, it does not execute the extraction.
/// See `ExtractComponentPlugin` to actually perform the extraction.
///
/// If you only want to extract a component conditionally, you may use the `extract_component_filter` attribute.
///
/// # Example
///
/// ```no_compile
/// use bevy_ecs::component::Component;
/// use bevy_render_macros::ExtractComponent;
///
/// #[derive(Component, Clone, ExtractComponent)]
/// #[extract_component_filter(With<Camera>)]
/// pub struct Foo {
/// pub should_foo: bool,
/// }
///
/// // Without a filter (unconditional).
/// #[derive(Component, Clone, ExtractComponent)]
/// pub struct Bar {
/// pub should_bar: bool,
/// }
/// ```
#[proc_macro_derive(ExtractComponent, attributes(extract_component_filter))]
pub fn derive_extract_component(input: TokenStream) -> TokenStream {
extract_component::derive_extract_component(input)
}
#[proc_macro_derive(
AsBindGroup,
attributes(
uniform,
storage_texture,
texture,
sampler,
bind_group_data,
storage,
bindless,
data
)
)]
pub fn derive_as_bind_group(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
as_bind_group::derive_as_bind_group(input).unwrap_or_else(|err| err.to_compile_error().into())
}
/// Derive macro generating an impl of the trait `RenderLabel`.
///
/// This does not work for unions.
#[proc_macro_derive(RenderLabel)]
pub fn derive_render_label(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let mut trait_path = bevy_render_path();
trait_path
.segments
.push(format_ident!("render_graph").into());
trait_path
.segments
.push(format_ident!("RenderLabel").into());
derive_label(input, "RenderLabel", &trait_path)
}
/// Derive macro generating an impl of the trait `RenderSubGraph`.
///
/// This does not work for unions.
#[proc_macro_derive(RenderSubGraph)]
pub fn derive_render_sub_graph(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let mut trait_path = bevy_render_path();
trait_path
.segments
.push(format_ident!("render_graph").into());
trait_path
.segments
.push(format_ident!("RenderSubGraph").into());
derive_label(input, "RenderSubGraph", &trait_path)
}
#[proc_macro_derive(ShaderLabel)]
pub fn derive_shader_label(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let mut trait_path = bevy_render_path();
trait_path
.segments
.push(format_ident!("render_phase").into());
trait_path
.segments
.push(format_ident!("ShaderLabel").into());
derive_label(input, "ShaderLabel", &trait_path)
}
#[proc_macro_derive(DrawFunctionLabel)]
pub fn derive_draw_function_label(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let mut trait_path = bevy_render_path();
trait_path
.segments
.push(format_ident!("render_phase").into());
trait_path
.segments
.push(format_ident!("DrawFunctionLabel").into());
derive_label(input, "DrawFunctionLabel", &trait_path)
}