71 lines
2.4 KiB
Rust
71 lines
2.4 KiB
Rust
use crate::modules::{get_modules, get_path};
|
|
use inflector::Inflector;
|
|
use proc_macro::TokenStream;
|
|
use proc_macro2::Ident;
|
|
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.attrs);
|
|
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)
|
|
}
|
|
}
|
|
})
|
|
}
|