shader_defs: new leaner shader defs. they are now separate from uniforms

crates/bevy_derive/src/lib.rs

@@ -8,6 +8,7 @@ mod modules;
 mod render_resources;
 mod render_resource;
 mod resource;
+mod shader_defs;
 mod uniforms;
 mod as_vertex_buffer_descriptor;
 
@@ -43,6 +44,11 @@ pub fn derive_render_resource(input: TokenStream) -> TokenStream {
     render_resource::derive_render_resource(input)
 }
 
+#[proc_macro_derive(ShaderDefs, attributes(shader_def, module))]
+pub fn derive_shader_defs(input: TokenStream) -> TokenStream {
+    shader_defs::derive_shader_defs(input)
+}
+
 #[proc_macro_derive(AsVertexBufferDescriptor, attributes(vertex, module))]
 pub fn derive_as_vertex_buffer_descriptor(input: TokenStream) -> TokenStream {
     as_vertex_buffer_descriptor::derive_as_vertex_buffer_descriptor(input)

crates/bevy_derive/src/shader_defs.rs

@@ -0,0 +1,71 @@
+use crate::modules::{get_modules, get_path};
+use proc_macro::TokenStream;
+use proc_macro2::Ident;
+use inflector::Inflector;
+use quote::quote;
+use syn::{parse_macro_input, Data, DataStruct, DeriveInput, Fields, Path};
+
+static SHADER_DEF_ATTRIBUTE_NAME: &'static str = "shader_def";
+
+pub fn derive_shader_defs(input: TokenStream) -> TokenStream {
+    let ast = parse_macro_input!(input as DeriveInput);
+    let modules = get_modules(&ast);
+    let bevy_render_path: Path = get_path(&modules.bevy_render);
+
+    let fields = match &ast.data {
+        Data::Struct(DataStruct {
+            fields: Fields::Named(fields),
+            ..
+        }) => &fields.named,
+        _ => panic!("expected a struct with named fields"),
+    };
+
+    let shader_def_idents = fields
+        .iter()
+        .filter(|f| {
+            f.attrs
+                .iter()
+                .find(|a| {
+                    a.path.get_ident().as_ref().unwrap().to_string() == SHADER_DEF_ATTRIBUTE_NAME
+                })
+                .is_some()
+        })
+        .map(|f| f.ident.as_ref().unwrap())
+        .collect::<Vec<&Ident>>();
+    let struct_name = &ast.ident;
+    let struct_name_pascal_case = ast.ident.to_string().to_pascal_case();
+    let shader_defs = shader_def_idents
+        .iter()
+        .map(|i| format!("{}_{}", struct_name_pascal_case, i.to_string()).to_uppercase());
+
+    let shader_defs_len = shader_defs.len();
+    let shader_def_indices = 0..shader_defs_len;
+
+    let generics = ast.generics;
+    let (impl_generics, ty_generics, _where_clause) = generics.split_for_impl();
+
+
+    TokenStream::from(quote! {
+        impl #impl_generics #bevy_render_path::shader::ShaderDefs for #struct_name#ty_generics {
+            fn shader_defs_len(&self) -> usize {
+                #shader_defs_len
+            }
+
+            fn get_shader_def(&self, index: usize) -> Option<&str> {
+                use #bevy_render_path::shader::ShaderDef;
+                match index {
+                    #(#shader_def_indices => if self.#shader_def_idents.is_defined() {
+                        Some(#shader_defs)
+                    } else {
+                        None
+                    },)*
+                    _ => None,
+                }
+            }
+
+            fn iter_shader_defs(&self) -> #bevy_render_path::shader::ShaderDefIterator {
+                #bevy_render_path::shader::ShaderDefIterator::new(self)
+            }
+        }
+    })
+}

crates/bevy_derive/src/uniforms.rs

@@ -138,15 +138,7 @@ pub fn derive_uniforms(input: TokenStream) -> TokenStream {
             // TODO: this will be very allocation heavy. find a way to either make this allocation free
             // or alternatively only run it when the shader_defs have changed
             fn get_shader_defs(&self) -> Option<Vec<String>> {
-                use #bevy_render_path::shader::ShaderDefSuffixProvider;
-                let mut potential_shader_defs: Vec<(&'static str, Option<&'static str>)> = vec![
-                    #((#shader_def_field_names_screaming_snake, self.#shader_def_field_names.get_shader_def()),)*
-                ];
-
-                Some(potential_shader_defs.drain(..)
-                    .filter(|(f, shader_def)| shader_def.is_some())
-                    .map(|(f, shader_def)| format!("{}_{}{}", #struct_name_uppercase, f, shader_def.unwrap()))
-                    .collect::<Vec<String>>())
+                None
             }
         }
     })

crates/bevy_pbr/src/material.rs

@@ -1,10 +1,10 @@
 use bevy_asset::{self, Handle};
-use bevy_render::{render_resource::RenderResources, shader::Uniforms, texture::Texture, Color};
+use bevy_render::{render_resource::RenderResources, shader::ShaderDefs, texture::Texture, Color};
 
-#[derive(Uniforms, RenderResources)]
+#[derive(RenderResources, ShaderDefs)]
 pub struct StandardMaterial {
     pub albedo: Color,
-    #[uniform(shader_def)]
+    #[shader_def]
     pub albedo_texture: Option<Handle<Texture>>,
 }
 

crates/bevy_render/src/shader/mod.rs

@@ -1,8 +1,10 @@
 mod shader;
+mod shader_defs;
 mod shader_reflect;
 mod uniform;
 pub mod uniforms;
 
 pub use shader::*;
+pub use shader_defs::*;
 pub use shader_reflect::*;
-pub use uniform::*;
+pub use uniform::*;

crates/bevy_render/src/shader/shader_defs.rs

@@ -0,0 +1,92 @@
+
+use bevy_asset::{Assets, Handle};
+use crate::{Renderable, texture::Texture};
+use legion::prelude::{Res, Com, ComMut};
+
+pub use bevy_derive::ShaderDefs;
+
+pub trait ShaderDef {
+    fn is_defined(&self) -> bool;
+}
+
+pub trait ShaderDefs {
+    fn shader_defs_len(&self) -> usize;
+    fn get_shader_def(&self, index: usize) -> Option<&str>;
+    fn iter_shader_defs(&self) -> ShaderDefIterator;
+}
+
+
+pub struct ShaderDefIterator<'a> {
+    shader_defs: &'a dyn ShaderDefs,
+    index: usize,
+}
+
+impl<'a> ShaderDefIterator<'a> {
+    pub fn new(shader_defs: &'a dyn ShaderDefs) -> Self {
+        Self {
+            shader_defs,
+            index: 0,
+        }
+    }
+}
+impl<'a> Iterator for ShaderDefIterator<'a> {
+    type Item = &'a str;
+    fn next(&mut self) -> Option<Self::Item> {
+        loop {
+            if self.index == self.shader_defs.shader_defs_len() {
+                return None;
+            } 
+            let shader_def = self
+                .shader_defs
+                .get_shader_def(self.index);
+            self.index += 1;
+            if shader_def.is_some() {
+               return shader_def; 
+            }
+        }
+    }
+}
+
+impl ShaderDef for bool {
+    fn is_defined(&self) -> bool {
+        *self
+    }
+}
+
+impl ShaderDef for Option<Handle<Texture>> {
+    fn is_defined(&self) -> bool {
+        self.is_some()
+    }
+}
+
+pub fn shader_def_system<T>(shader_defs: Com<T>, mut renderable: ComMut<Renderable>)
+where
+    T: ShaderDefs + Send + Sync + 'static,
+{
+    for shader_def in shader_defs.iter_shader_defs() {
+        renderable
+            .render_resource_assignments
+            .pipeline_specialization
+            .shader_specialization
+            .shader_defs
+            .insert(shader_def.to_string());
+    }
+}
+
+pub fn asset_shader_def_system<T>(
+    assets: Res<Assets<T>>,
+    asset_handle: Com<Handle<T>>,
+    mut renderable: ComMut<Renderable>,
+) where
+    T: ShaderDefs + Send + Sync + 'static,
+{
+    let shader_defs = assets.get(&asset_handle).unwrap();
+    for shader_def in shader_defs.iter_shader_defs() {
+        renderable
+            .render_resource_assignments
+            .pipeline_specialization
+            .shader_specialization
+            .shader_defs
+            .insert(shader_def.to_string());
+    }
+}

crates/bevy_render/src/shader/uniform.rs

@@ -1,6 +1,5 @@
-use crate::{pipeline::BindType, texture::Texture, Renderable};
-use bevy_asset::{Assets, Handle};
-use legion::prelude::*;
+use crate::{pipeline::BindType, texture::Texture};
+use bevy_asset::Handle;
 
 pub use bevy_derive::{Uniform, Uniforms};
 
@@ -13,42 +12,6 @@ pub trait Uniforms: Send + Sync + 'static {
     fn get_field_bind_type(&self, name: &str) -> Option<FieldBindType>;
 }
 
-pub fn shader_def_system<T>(uniforms: Com<T>, mut renderable: ComMut<Renderable>)
-where
-    T: Uniforms + Send + Sync + 'static,
-{
-    if let Some(shader_defs) = uniforms.get_shader_defs() {
-        renderable
-            .render_resource_assignments
-            .pipeline_specialization
-            .shader_specialization
-            .shader_defs
-            .extend(shader_defs)
-    }
-}
-
-pub fn asset_shader_def_system<T>(
-    assets: Res<Assets<T>>,
-    asset_handle: Com<Handle<T>>,
-    mut renderable: ComMut<Renderable>,
-) where
-    T: Uniforms + Send + Sync + 'static,
-{
-    if !renderable.is_visible || renderable.is_instanced {
-        return;
-    }
-
-    let uniforms = assets.get(&asset_handle).unwrap();
-    if let Some(shader_defs) = uniforms.get_shader_defs() {
-        renderable
-            .render_resource_assignments
-            .pipeline_specialization
-            .shader_specialization
-            .shader_defs
-            .extend(shader_defs)
-    }
-}
-
 pub trait ShaderDefSuffixProvider {
     fn get_shader_def(&self) -> Option<&'static str>;
 }

crates/bevy_sprite/src/color_material.rs

@@ -1,10 +1,10 @@
 use bevy_asset::{self, Handle};
-use bevy_render::{texture::Texture, Color, render_resource::RenderResources, shader::Uniforms};
+use bevy_render::{render_resource::RenderResources, shader::ShaderDefs, texture::Texture, Color};
 
-#[derive(Uniforms, RenderResources)]
+#[derive(RenderResources, ShaderDefs)]
 pub struct ColorMaterial {
     pub color: Color,
-    #[uniform(shader_def)]
+    #[shader_def]
     pub texture: Option<Handle<Texture>>,
 }
 

crates/bevy_sprite/src/texture_atlas.rs

@@ -1,26 +1,27 @@
 use crate::Rect;
 use bevy_asset::Handle;
-use bevy_render::{texture::Texture, render_resource::{RenderResources, RenderResource}, shader::{Uniforms, Uniform}};
 use bevy_core::bytes::Bytes;
+use bevy_render::{
+    render_resource::{RenderResource, RenderResources},
+    texture::Texture,
+};
 use glam::{Vec2, Vec3};
 use std::collections::HashMap;
 
-#[derive(Uniforms, RenderResources)]
+#[derive(RenderResources)]
 pub struct TextureAtlas {
     pub texture: Handle<Texture>,
     // TODO: add support to Uniforms derive to write dimensions and sprites to the same buffer
     pub dimensions: Vec2,
-    #[uniform(buffer)]
     #[render_resources(buffer)]
     pub textures: Vec<Rect>,
-    #[uniform(ignore)]
     #[render_resources(ignore)]
     pub texture_handles: Option<HashMap<Handle<Texture>, usize>>,
 }
 
 // NOTE: cannot do `unsafe impl Byteable` here because Vec3 takes up the space of a Vec4. If/when glam changes this we can swap out
 // Bytes for Byteable as a micro-optimization. https://github.com/bitshifter/glam-rs/issues/36
-#[derive(Uniform, Bytes, RenderResources, RenderResource, Default)]
+#[derive(Bytes, RenderResources, RenderResource, Default)]
 #[render_resources(from_self)]
 pub struct TextureAtlasSprite {
     pub position: Vec3,

examples/shader/shader_custom_material.rs

@@ -8,7 +8,7 @@ fn main() {
         .run();
 }
 
-#[derive(Uniforms, RenderResources, Default)]
+#[derive(RenderResources, Default)]
 struct MyMaterial {
     pub color: Color,
 }

examples/shader/shader_defs.rs

@@ -12,11 +12,11 @@ fn main() {
         .run();
 }
 
-#[derive(Uniforms, RenderResources, Default)]
+#[derive(RenderResources, ShaderDefs, Default)]
 struct MyMaterial {
     pub color: Color,
-    #[uniform(ignore, shader_def)]
     #[render_resources(ignore)]
+    #[shader_def]
     pub always_red: bool,
 }
 

src/prelude.rs

@@ -1,7 +1,7 @@
 pub use crate::{
     app::{
-        schedule_runner::ScheduleRunnerPlugin, stage, App, AppBuilder, AppPlugin, EntityArchetype,
-        EventReader, Events, FromResources, System, DynamicAppPlugin
+        schedule_runner::ScheduleRunnerPlugin, stage, App, AppBuilder, AppPlugin, DynamicAppPlugin,
+        EntityArchetype, EventReader, Events, FromResources, System,
     },
     asset::{AddAsset, AssetEvent, AssetServer, Assets, Handle},
     core::{
@@ -25,8 +25,10 @@ pub use crate::{
             },
             RenderGraph,
         },
-        shader::{Shader, ShaderDefSuffixProvider, ShaderStage, ShaderStages, Uniforms},
         render_resource::RenderResources,
+        shader::{
+            Shader, ShaderDefSuffixProvider, ShaderDefs, ShaderStage, ShaderStages, Uniforms,
+        },
         texture::Texture,
         Camera, Color, ColorSource, OrthographicProjection, PerspectiveProjection, Renderable,
     },