fix architype capacity issue

internal/storage/storage.go

@@ -24,6 +24,9 @@ func NewStorage() *Storage {
 
 // PushComponent stores the new data of the component in the archetype.
 func (cs *Storage) PushComponent(component component.IComponentType, archetypeIndex ArchetypeIndex) {
+	if len(cs.storages) <= int(archetypeIndex) {
+		cs.ensureCapacity(archetypeIndex)
+	}
 	if v := cs.storages[archetypeIndex]; v == nil {
 		cs.storages[archetypeIndex] = []unsafe.Pointer{}
 	}
@@ -44,6 +47,10 @@ func (cs *Storage) SetComponent(archetypeIndex ArchetypeIndex, componentIndex Co
 
 // MoveComponent moves the pointer to data of the component in the archetype.
 func (cs *Storage) MoveComponent(source ArchetypeIndex, index ComponentIndex, dst ArchetypeIndex) {
+	if len(cs.storages) <= int(dst) {
+		cs.ensureCapacity(dst)
+	}
+
 	src_slice := cs.storages[source]
 	dst_slice := cs.storages[dst]
 
@@ -74,3 +81,9 @@ func (cs *Storage) Contains(archetypeIndex ArchetypeIndex, componentIndex Compon
 	}
 	return cs.storages[archetypeIndex][componentIndex] != nil
 }
+
+func (cs *Storage) ensureCapacity(archetypeIndex ArchetypeIndex) {
+	newStorages := make([][]unsafe.Pointer, len(cs.storages)*2)
+	copy(newStorages, cs.storages)
+	cs.storages = newStorages
+}

world_test.go

@@ -193,6 +193,25 @@ func TestDeleteEntity(t *testing.T) {
 	}
 }
 
+func TestArchetypeStorageExpands(t *testing.T) {
+	world := donburi.NewWorld()
+	dummy := donburi.NewTag()
+	entry := world.Entry(world.Create(dummy))
+	const N = 256
+	for i := 0; i < N; i++ {
+		tag := donburi.NewTag()
+		entry.AddComponent(tag)
+	}
+	q := donburi.NewQuery(filter.Contains(dummy))
+	e, ok := q.First(world)
+	if !ok {
+		t.Fatalf("Entity should be found")
+	}
+	if len(e.Archetype().Layout().Components()) != N+1 {
+		t.Fatalf("Archetype should have 301 components")
+	}
+}
+
 func TestRemoveAndCreateEntity(t *testing.T) {
 	world := donburi.NewWorld()