1 files changed, 23 insertions, 2 deletions
diff --git a/ecs/src/archetype.rs b/ecs/src/archetype.rs
index a33de66..808d006 100644
--- a/ecs/src/archetype.rs
+++ b/ecs/src/archetype.rs
@@ -1,6 +1,10 @@
 use std::hash::{DefaultHasher, Hash, Hasher};
 
-use crate::component::Id as ComponentId;
+use crate::component::{
+    Id as ComponentId,
+    IsOptional as ComponentIsOptional,
+    Metadata as ComponentMetadata,
+};
 
 /// Archetype ID.
 #[derive(Debug, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
@@ -11,8 +15,25 @@ pub struct Id
 
 impl Id
 {
+    pub fn from_components_metadata(
+        components_metadata: impl IntoIterator<Item = ComponentMetadata>,
+    ) -> Self
+    {
+        Self::new(
+            components_metadata
+                .into_iter()
+                .filter_map(|component_metadata| {
+                    if component_metadata.is_optional == ComponentIsOptional::Yes {
+                        return None;
+                    }
+
+                    Some(component_metadata.id)
+                }),
+        )
+    }
+
     /// Returns the ID of a archetype with the given components.
-    pub fn new(component_ids: impl IntoIterator<Item = ComponentId>) -> Self
+    fn new(component_ids: impl IntoIterator<Item = ComponentId>) -> Self
     {
         let mut hasher = DefaultHasher::new();