node_macro: add shader_nodes option

Author: Firestar99

Cargo.lock

@@ -154,6 +154,7 @@ tinyvec = { version = "1", features = ["std"] }
 criterion = { version = "0.5", features = ["html_reports"] }
 iai-callgrind = { version = "0.12.3" }
 ndarray = "0.16.1"
+strum = { version = "0.26.3", features = ["derive"] }
 
 [profile.dev]
 opt-level = 1

Cargo.toml

@@ -19,6 +19,7 @@ syn = { workspace = true }
 proc-macro2 = { workspace = true }
 quote = { workspace = true }
 convert_case = { workspace = true }
+strum = { workspace = true }
 
 indoc = "2.0.5"
 proc-macro-crate = "3.1.0"

node-graph/node-macro/Cargo.toml

@@ -345,7 +345,7 @@ pub(crate) fn generate_node_code(parsed: &ParsedNodeFn) -> syn::Result<TokenStre
 
 	let properties = &attributes.properties_string.as_ref().map(|value| quote!(Some(#value))).unwrap_or(quote!(None));
 
-	let cfg = if let Some(cfg) = &attributes.cfg { quote!(#[cfg(#cfg)]) } else { quote!() };
+	let cfg = crate::shader_nodes::modify_cfg(&attributes);
 	let node_input_accessor = generate_node_input_references(parsed, fn_generics, &field_idents, &graphene_core, &identifier, &cfg);
 	Ok(quote! {
 		/// Underlying implementation for [#struct_name]

node-graph/node-macro/src/codegen.rs

@@ -5,6 +5,7 @@ use syn::GenericParam;
 mod codegen;
 mod derive_choice_type;
 mod parsing;
+mod shader_nodes;
 mod validation;
 
 /// Used to create a node definition.

node-graph/node-macro/src/lib.rs

@@ -12,6 +12,7 @@ use syn::{
 };
 
 use crate::codegen::generate_node_code;
+use crate::shader_nodes::ShaderNodeType;
 
 #[derive(Debug)]
 pub(crate) struct Implementation {
@@ -47,6 +48,8 @@ pub(crate) struct NodeFnAttributes {
 	pub(crate) properties_string: Option<LitStr>,
 	/// whether to `#[cfg]` gate the node implementation, defaults to None
 	pub(crate) cfg: Option<TokenStream2>,
+	/// if this node should get a gpu implementation, defaults to None
+	pub(crate) shader_node: Option<ShaderNodeType>,
 	// Add more attributes as needed
 }
 
@@ -187,6 +190,7 @@ impl Parse for NodeFnAttributes {
 		let mut skip_impl = false;
 		let mut properties_string = None;
 		let mut cfg = None;
+		let mut shader_node = None;
 
 		let content = input;
 		// let content;
@@ -249,6 +253,13 @@ impl Parse for NodeFnAttributes {
 					let meta = meta.require_list()?;
 					cfg = Some(meta.tokens.clone());
 				}
+				"shader_node" => {
+					if shader_node.is_some() {
+						return Err(Error::new_spanned(path, "Multiple 'feature' attributes are not allowed"));
+					}
+					let meta = meta.require_list()?;
+					shader_node = Some(syn::parse2(meta.tokens.to_token_stream())?);
+				}
 				_ => {
 					return Err(Error::new_spanned(
 						meta,
@@ -273,6 +284,7 @@ impl Parse for NodeFnAttributes {
 			skip_impl,
 			properties_string,
 			cfg,
+			shader_node,
 		})
 	}
 }

node-graph/node-macro/src/parsing.rs

@@ -0,0 +1,32 @@
+use crate::parsing::NodeFnAttributes;
+use proc_macro2::{Ident, TokenStream};
+use quote::quote;
+use strum::{EnumString, VariantNames};
+use syn::Error;
+use syn::parse::{Parse, ParseStream};
+
+pub const STD_FEATURE_GATE: &str = "std";
+
+pub fn modify_cfg(attributes: &NodeFnAttributes) -> TokenStream {
+	match (&attributes.cfg, &attributes.shader_node) {
+		(Some(cfg), Some(_)) => quote!(#[cfg(all(#cfg, feature = #STD_FEATURE_GATE))]),
+		(Some(cfg), None) => quote!(#[cfg(#cfg)]),
+		(None, Some(_)) => quote!(#[cfg(feature = #STD_FEATURE_GATE)]),
+		(None, None) => quote!(),
+	}
+}
+
+#[derive(Debug, EnumString, VariantNames)]
+pub(crate) enum ShaderNodeType {
+	PerPixelAdjust,
+}
+
+impl Parse for ShaderNodeType {
+	fn parse(input: ParseStream) -> syn::Result<Self> {
+		let ident: Ident = input.parse()?;
+		Ok(match ident.to_string().as_str() {
+			"PerPixelAdjust" => ShaderNodeType::PerPixelAdjust,
+			_ => return Err(Error::new_spanned(&ident, format!("attr 'shader_node' must be one of {:?}", Self::VARIANTS))),
+		})
+	}
+}