[Merged by Bors] - Support storage buffers in derive AsBindGroup

crates/bevy_render/macros/src/as_bind_group.rs

@@ -11,13 +11,15 @@ use syn::{
 const UNIFORM_ATTRIBUTE_NAME: Symbol = Symbol("uniform");
 const TEXTURE_ATTRIBUTE_NAME: Symbol = Symbol("texture");
 const SAMPLER_ATTRIBUTE_NAME: Symbol = Symbol("sampler");
+const STORAGE_ATTRIBUTE_NAME: Symbol = Symbol("storage");
 const BIND_GROUP_DATA_ATTRIBUTE_NAME: Symbol = Symbol("bind_group_data");
 
 #[derive(Copy, Clone, Debug)]
 enum BindingType {
  Uniform,
  Texture,
  Sampler,
+ Storage,
 }
 
 #[derive(Clone)]
@@ -55,7 +57,6 @@ pub fn derive_as_bind_group(ast: syn::DeriveInput) -> Result<TokenStream> {
  }
  } else if attr_ident == UNIFORM_ATTRIBUTE_NAME {
  let (binding_index, converted_shader_type) = get_uniform_binding_attr(attr)?;
-
  binding_impls.push(quote! {{
  use #render_path::render_resource::AsBindGroupShaderType;
  let mut buffer = #render_path::render_resource::encase::UniformBuffer::new(Vec::new());
@@ -126,6 +127,8 @@ pub fn derive_as_bind_group(ast: syn::DeriveInput) -> Result<TokenStream> {
  BindingType::Texture
  } else if attr_ident == SAMPLER_ATTRIBUTE_NAME {
  BindingType::Sampler
+ } else if attr_ident == STORAGE_ATTRIBUTE_NAME {
+ BindingType::Storage
  } else {
  continue;
  };
@@ -190,7 +193,45 @@ pub fn derive_as_bind_group(ast: syn::DeriveInput) -> Result<TokenStream> {
  }
 
  match binding_type {
- BindingType::Uniform => { /* uniform codegen is deferred to account for combined uniform bindings */
+ BindingType::Uniform => {
+ // uniform codegen is deferred to account for combined uniform bindings
+ }
+ BindingType::Storage => {
+ let StorageAttrs {
+ visibility,
+ read_only,
+ } = get_storage_binding_attr(nested_meta_items)?;
+ let visibility =
+ visibility.hygenic_quote(&quote! { #render_path::render_resource });
+
+ let field_name = field.ident.as_ref().unwrap();
+ let field_ty = &field.ty;
+
+ binding_impls.push(quote! {{
+ use #render_path::render_resource::AsBindGroupShaderType;
+ let mut buffer = #render_path::render_resource::encase::StorageBuffer::new(Vec::new());
+ buffer.write(&self.#field_name).unwrap();
+ #render_path::render_resource::OwnedBindingResource::Buffer(render_device.create_buffer_with_data(
+ &#render_path::render_resource::BufferInitDescriptor {
+ label: None,
+ usage: #render_path::render_resource::BufferUsages::COPY_DST | #render_path::render_resource::BufferUsages::STORAGE,
+ contents: buffer.as_ref(),
+ },
+ ))
+ }});
+
+ binding_layouts.push(quote! {
+ #render_path::render_resource::BindGroupLayoutEntry {
+ binding: #binding_index,
+ visibility: #visibility,
+ ty: #render_path::render_resource::BindingType::Buffer {
+ ty: #render_path::render_resource::BufferBindingType::Storage { read_only: #read_only },
+ has_dynamic_offset: false,
+ min_binding_size: Some(<#field_ty as #render_path::render_resource::ShaderType>::min_size()),
+ },
+ count: None,
+ }
+ });
  }
  BindingType::Texture => {
  let TextureAttrs {
@@ -861,3 +902,40 @@ fn get_sampler_binding_type_value(lit_str: &LitStr) -> Result<SamplerBindingType
  )),
  }
 }
+
+#[derive(Default)]
+struct StorageAttrs {
+ visibility: ShaderStageVisibility,
+ read_only: bool,
+}
+
+const READ_ONLY: Symbol = Symbol("read_only");
+
+fn get_storage_binding_attr(metas: Vec<NestedMeta>) -> Result<StorageAttrs> {
+ let mut visibility = ShaderStageVisibility::vertex_fragment();
+ let mut read_only = false;
+
+ for meta in metas {
+ use syn::{Meta::List, Meta::Path, NestedMeta::Meta};
+ match meta {
+ // Parse #[storage(0, visibility(...))].
+ Meta(List(m)) if m.path == VISIBILITY => {
+ visibility = get_visibility_flag_value(&m.nested)?;
+ }
+ Meta(Path(path)) if path == READ_ONLY => {
+ read_only = true;
+ }
+ _ => {
+ return Err(Error::new_spanned(
+ meta,
+ "Not a valid attribute. Available attributes: `read_only`, `visibility`",
+ ));
+ }
+ }
+ }
+
+ Ok(StorageAttrs {
+ visibility,
+ read_only,
+ })
+}

crates/bevy_render/macros/src/lib.rs

@@ -17,7 +17,10 @@ pub fn derive_extract_resource(input: TokenStream) -> TokenStream {
  extract_resource::derive_extract_resource(input)
 }
 
-#[proc_macro_derive(AsBindGroup, attributes(uniform, texture, sampler, bind_group_data))]
+#[proc_macro_derive(
+ AsBindGroup,
+ attributes(uniform, texture, sampler, bind_group_data, storage)
+)]
 pub fn derive_as_bind_group(input: TokenStream) -> TokenStream {
  let input = parse_macro_input!(input as DeriveInput);
 

crates/bevy_render/src/render_resource/bind_group.rs

@@ -82,6 +82,8 @@ impl Deref for BindGroup {
 /// #[texture(1)]
 /// #[sampler(2)]
 /// color_texture: Handle<Image>,
+/// #[storage(3, read_only)]
+/// values: Vec<f32>,
 /// }
 /// ```
 ///
@@ -94,6 +96,8 @@ impl Deref for BindGroup {
 /// var color_texture: texture_2d<f32>;
 /// @group(1) @binding(2)
 /// var color_sampler: sampler;
+/// @gropu(1) @binding(3)
+/// var<storage> values: array<f32>;
 /// ```
 /// Note that the "group" index is determined by the usage context. It is not defined in [`AsBindGroup`]. For example, in Bevy material bind groups
 /// are generally bound to group 1.
@@ -132,6 +136,15 @@ impl Deref for BindGroup {
 /// | `sampler_type` = "..." | `"filtering"`, `"non_filtering"`, `"comparison"`. | `"filtering"` |
 /// | `visibility(...)` | `all`, `none`, or a list-combination of `vertex`, `fragment`, `compute` | `vertex`, `fragment` |
 ///
+/// * `storage(BINDING_INDEX, arguments)`
+/// * The field will be converted to a shader-compatible type using the [`ShaderType`] trait, written to a [`Buffer`], and bound as a storage buffer.
+/// * It supports and optional `read_only` parameter. Defaults to false if not present.
+///
+/// | Arguments | Values | Default |
+/// |------------------------|-------------------------------------------------------------------------|----------------------|
+/// | `visibility(...)` | `all`, `none`, or a list-combination of `vertex`, `fragment`, `compute` | `vertex`, `fragment` |
+/// | `read_only` | if present then value is true, otherwise false | `false` |
+///
 /// Note that fields without field-level binding attributes will be ignored.
 /// ```
 /// # use bevy_render::{color::Color, render_resource::AsBindGroup};