shader-nodes feature: put shader nodes behind feature gate

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

@@ -295,7 +295,7 @@ pub(crate) fn generate_node_code(parsed: &ParsedNodeFn) -> syn::Result<TokenStre
 
 	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);
-	let ShaderTokens { shader_entry_point, gpu_node } = attributes.shader_node.as_ref().map(|n| n.codegen(parsed, &cfg)).unwrap_or(Ok(ShaderTokens::default()))?;
+	let ShaderTokens { shader_entry_point, gpu_node } = attributes.shader_node.as_ref().map(|n| n.codegen(parsed)).unwrap_or(Ok(ShaderTokens::default()))?;
 
 	Ok(quote! {
 		/// Underlying implementation for [#struct_name]

node-graph/node-macro/src/shader_nodes/mod.rs

@@ -3,28 +3,38 @@ use crate::shader_nodes::per_pixel_adjust::PerPixelAdjust;
 use proc_macro2::{Ident, TokenStream};
 use quote::quote;
 use strum::VariantNames;
-use syn::Error;
 use syn::parse::{Parse, ParseStream};
+use syn::punctuated::Punctuated;
+use syn::{Error, Token};
 
 pub mod per_pixel_adjust;
 
 pub const STD_FEATURE_GATE: &str = "std";
+pub const SHADER_NODES_FEATURE_GATE: &str = "shader-nodes";
 
 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!(),
-	}
+	let feature_gate = match &attributes.shader_node {
+		// shader node cfg is done on the mod
+		Some(ShaderNodeType::ShaderNode) => quote!(),
+		Some(_) => quote!(feature = #STD_FEATURE_GATE),
+		None => quote!(),
+	};
+	let cfgs: Punctuated<_, Token![,]> = match &attributes.cfg {
+		None => [&feature_gate].into_iter().collect(),
+		Some(cfg) => [cfg, &feature_gate].into_iter().collect(),
+	};
+	quote!(#[cfg(all(#cfgs))])
 }
 
 #[derive(Debug, Clone, VariantNames)]
 pub(crate) enum ShaderNodeType {
+	/// Marker for this node being in a gpu node crate, but not having a gpu implementation. This is distinct from not
+	/// declaring `shader_node` at all, as it will wrap the CPU node with a `#[cfg(feature = "std")]` feature gate.
+	None,
 	/// Marker for this node being a generated gpu node implementation, that should not emit anything to prevent
 	/// recursively generating more gpu nodes. But it still counts as a gpu node and will get the
 	/// `#[cfg(feature = "std")]` feature gate around it's impl.
-	GpuNode,
+	ShaderNode,
 	PerPixelAdjust(PerPixelAdjust),
 }
 
@@ -32,6 +42,7 @@ impl Parse for ShaderNodeType {
 	fn parse(input: ParseStream) -> syn::Result<Self> {
 		let ident: Ident = input.parse()?;
 		Ok(match ident.to_string().as_str() {
+			"None" => ShaderNodeType::None,
 			"PerPixelAdjust" => ShaderNodeType::PerPixelAdjust(PerPixelAdjust::parse(input)?),
 			_ => return Err(Error::new_spanned(&ident, format!("attr 'shader_node' must be one of {:?}", Self::VARIANTS))),
 		})
@@ -39,13 +50,13 @@ impl Parse for ShaderNodeType {
 }
 
 pub trait ShaderCodegen {
-	fn codegen(&self, parsed: &ParsedNodeFn, node_cfg: &TokenStream) -> syn::Result<ShaderTokens>;
+	fn codegen(&self, parsed: &ParsedNodeFn) -> syn::Result<ShaderTokens>;
 }
 
 impl ShaderCodegen for ShaderNodeType {
-	fn codegen(&self, parsed: &ParsedNodeFn, node_cfg: &TokenStream) -> syn::Result<ShaderTokens> {
+	fn codegen(&self, parsed: &ParsedNodeFn) -> syn::Result<ShaderTokens> {
 		match self {
-			ShaderNodeType::GpuNode => (),
+			ShaderNodeType::None | ShaderNodeType::ShaderNode => (),
 			_ => {
 				if parsed.is_async {
 					return Err(Error::new_spanned(&parsed.fn_name, "Shader nodes must not be async"));
@@ -54,8 +65,8 @@ impl ShaderCodegen for ShaderNodeType {
 		}
 
 		match self {
-			ShaderNodeType::GpuNode => Ok(ShaderTokens::default()),
-			ShaderNodeType::PerPixelAdjust(x) => x.codegen(parsed, node_cfg),
+			ShaderNodeType::None | ShaderNodeType::ShaderNode => Ok(ShaderTokens::default()),
+			ShaderNodeType::PerPixelAdjust(x) => x.codegen(parsed),
 		}
 	}
 }

node-graph/node-macro/src/shader_nodes/per_pixel_adjust.rs

@@ -1,5 +1,5 @@
 use crate::parsing::{Input, NodeFnAttributes, ParsedField, ParsedFieldType, ParsedNodeFn, RegularParsedField};
-use crate::shader_nodes::{ShaderCodegen, ShaderNodeType, ShaderTokens};
+use crate::shader_nodes::{SHADER_NODES_FEATURE_GATE, ShaderCodegen, ShaderNodeType, ShaderTokens};
 use convert_case::{Case, Casing};
 use proc_macro_crate::FoundCrate;
 use proc_macro2::{Ident, TokenStream};
@@ -19,7 +19,7 @@ impl Parse for PerPixelAdjust {
 }
 
 impl ShaderCodegen for PerPixelAdjust {
-	fn codegen(&self, parsed: &ParsedNodeFn, node_cfg: &TokenStream) -> syn::Result<ShaderTokens> {
+	fn codegen(&self, parsed: &ParsedNodeFn) -> syn::Result<ShaderTokens> {
 		let fn_name = &parsed.fn_name;
 
 		let mut params;
@@ -75,7 +75,6 @@ impl ShaderCodegen for PerPixelAdjust {
 
 		let codegen = PerPixelAdjustCodegen {
 			parsed,
-			node_cfg,
 			params,
 			has_uniform,
 			entry_point_mod,
@@ -95,7 +94,6 @@ impl ShaderCodegen for PerPixelAdjust {
 
 pub struct PerPixelAdjustCodegen<'a> {
 	parsed: &'a ParsedNodeFn,
-	node_cfg: &'a TokenStream,
 	params: Vec<Param<'a>>,
 	has_uniform: bool,
 	entry_point_mod: Ident,
@@ -285,7 +283,7 @@ impl PerPixelAdjustCodegen<'_> {
 		let mut parsed_node_fn = ParsedNodeFn {
 			vis: self.parsed.vis.clone(),
 			attributes: NodeFnAttributes {
-				shader_node: Some(ShaderNodeType::GpuNode),
+				shader_node: Some(ShaderNodeType::ShaderNode),
 				..self.parsed.attributes.clone()
 			},
 			fn_name: self.gpu_node_mod.clone(),
@@ -309,10 +307,9 @@ impl PerPixelAdjustCodegen<'_> {
 		let gpu_node_impl = crate::codegen::generate_node_code(&parsed_node_fn)?;
 
 		// wrap node in `mod #gpu_node_mod`
-		let node_cfg = self.node_cfg;
 		let gpu_node_mod = &self.gpu_node_mod;
 		Ok(quote! {
-			#node_cfg
+			#[cfg(feature = #SHADER_NODES_FEATURE_GATE)]
 			mod #gpu_node_mod {
 				use super::*;
 				use wgpu_executor::WgpuExecutor;