Exposing ArchetypeComponents structs and implementing Default on them…

… if all of the components can be Default
recatek · Jan 28, 2025 · acbce58 · acbce58
1 parent 7f27b03
commit acbce58
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Showing 2 changed files with 47 additions and 7 deletions.
diff --git a/macros/src/generate/world.rs b/macros/src/generate/world.rs
@@ -27,6 +27,11 @@ pub fn generate_world(world_data: &DataWorld, raw_input: &str) -> TokenStream {
         .iter()
         .map(|archetype| format_ident!("{}", archetype.name))
         .collect::<Vec<_>>();
+    let ArchetypeComponents = world_data
+        .archetypes
+        .iter()
+        .map(|archetype| format_ident!("{}Components", archetype.name))
+        .collect::<Vec<_>>();
     let ArchetypeDirect = world_data
         .archetypes
         .iter()
@@ -76,23 +81,29 @@ pub fn generate_world(world_data: &DataWorld, raw_input: &str) -> TokenStream {
     let __expand_ecs_iter_destroy_hash = format_ident!("__expand_ecs_iter_destroy_{}", input_hash);
 
     quote!(
-        #( pub use #ecs_world_sealed::#Archetype; )*
-
         pub use #ecs_world_sealed::{
             #World,
             #WorldCapacity,
 
             SelectArchetype,
             SelectEntity,
-            SelectEntityDirect
+            SelectEntityDirect,
+
+            #(
+                #Archetype,
+                #ArchetypeComponents,
+            )*
         };
 
         #[doc(hidden)]
         pub use #ecs_world_sealed::{#__WorldSelectTotal};
 
         /// Convenience mod for accessing only archetypes in exports (for blob exports, etc.)
         pub mod archetypes {
-            #(pub use super::#Archetype;)*
+            #(
+                pub use super::#Archetype;
+                pub use super::#ArchetypeComponents;
+            )*
         }
 
         mod #ecs_world_sealed {
@@ -1003,6 +1014,18 @@ fn section_archetype(archetype_data: &DataArchetype) -> TokenStream {
             }
         }
 
+        impl Default for #ArchetypeComponents
+        where
+            #(for<'a> #Component: Default,)*
+        {
+            #[inline(always)]
+            fn default() -> Self {
+                Self {
+                    #(#component: #Component::default(),)*
+                }
+            }
+        }
+
         /// Access to all of the stored entity and component data within this archetype.
         /// Each index in these parallel slices refers to the components for a given entity.
         /// Component access is mutable, but entity access is fixed (entities can't be moved).

diff --git a/tests/test_clone.rs → tests/test_impls.rs b/tests/test_clone.rs → tests/test_impls.rs
@@ -1,10 +1,10 @@
 use gecs::prelude::*;
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Default, Debug, PartialEq)]
 pub struct CompA(pub u32);
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Default, Debug, PartialEq)]
 pub struct CompB(pub u32);
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Default, Debug, PartialEq)]
 pub struct CompC(pub u32);
 
 ecs_world! {
@@ -22,6 +22,23 @@ ecs_world! {
     );
 }
 
+#[test]
+pub fn test_default() {
+    let mut world = EcsWorld::default();
+
+    let entity_0 = world.create::<ArchFoo>(ArchFooComponents::default());
+    let entity_1 = world.create::<ArchBar>(ArchBarComponents {
+        comp_a: CompA(1),
+        ..Default::default()
+    });
+
+    let components_0 = world.destroy(entity_0).unwrap();
+    let components_1 = world.destroy(entity_1).unwrap();
+
+    assert_eq!(components_0.comp_a.0, 0);
+    assert_eq!(components_1.comp_a.0, 1);
+}
+
 #[test]
 #[rustfmt::skip]
 pub fn test_multi_find_clone() {