feat(engine): add tagged union info to enum reflection

1 files changed, 11 insertions, 14 deletions

diff --git a/engine-macros/src/reflection/enum_impl.rs b/engine-macros/src/reflection/enum_impl.rs
index 611da6d..5dbb176 100644
--- a/engine-macros/src/reflection/enum_impl.rs
+++ b/engine-macros/src/reflection/enum_impl.rs
@@ -219,23 +219,21 @@ pub fn generate(input: syn::ItemEnum) -> proc_macro2::TokenStream
         &engine_crate_path,
     );
 
-    let discriminant_layout = if is_unit_only {
-        quote! {
-            std::alloc::Layout::new::<Self>()
-        }
-    } else {
-        quote! {
-            std::alloc::Layout::new::<#mod_name::Discriminant>()
-        }
-    };
-
-    let fields_layout = if is_unit_only {
+    let tagged_union = if is_unit_only {
         quote! {
             None
         }
     } else {
         quote! {
-            Some(std::alloc::Layout::new::<#mod_name::Fields>())
+            Some(#engine_crate_path::reflection::EnumTaggedUnion {
+                discriminant_layout: std::alloc::Layout::new::<#mod_name::Discriminant>(),
+                discriminant_byte_offset:
+                    std::mem::offset_of!(#mod_name::Equivalent #type_generics, tag),
+                fields_layout:
+                    std::alloc::Layout::new::<#mod_name::Fields #type_generics>(),
+                fields_byte_offset:
+                    std::mem::offset_of!(#mod_name::Equivalent #type_generics, payload),
+            })
         }
     };
 
@@ -256,8 +254,7 @@ pub fn generate(input: syn::ItemEnum) -> proc_macro2::TokenStream
                         #engine_crate_path::reflection::Enum {
                             variants: &[#(#variants),*],
                             is_unit_only: #is_unit_only,
-                            discriminant_layout: #discriminant_layout,
-                            fields_layout: #fields_layout,
+                            tagged_union: #tagged_union,
                             get_default_value: || {
                                 #get_default_value_fn
                             }