engine/src/assets/pools/mesh_pool.cpp

@@ -4,6 +4,10 @@
 
 namespace sophia {
 
+namespace {
+constexpr u32 GENERATION_MASK = (1u << 12) - 1;
+}  // namespace
+
 MeshPool::MeshPool(Device& device) : device{device} {}
 
 MeshPool::~MeshPool() = default;
@@ -12,30 +16,43 @@ MeshHandle MeshPool::create(const Mesh::Builder& builder) {
   auto mesh = std::make_unique<Mesh>(device, builder);
 
   if (!freeList.empty()) {
-    MeshHandle handle = freeList.back();
+    u32 index = freeList.back();
     freeList.pop_back();
-    meshes[handle] = std::move(mesh);
+    slots[index].mesh = std::move(mesh);
-    return handle;
+    return MeshHandle{index, slots[index].generation};
   }
 
-  meshes.push_back(std::move(mesh));
+  slots.push_back(Slot{std::move(mesh), 0});
-  return static_cast<MeshHandle>(meshes.size() - 1);
+  return MeshHandle{static_cast<u32>(slots.size() - 1), 0};
 }
 
 const Mesh& MeshPool::get(MeshHandle handle) const {
-  SOPHIA_ASSERT(handle < meshes.size(), "invalid MeshHandle:", handle);
+  SOPHIA_ASSERT(handle.isValid(), "invalid MeshHandle");
-  SOPHIA_ASSERT(meshes[handle] != nullptr,
+  SOPHIA_ASSERT(handle.index < slots.size(),
-                "MeshHandle refers to a released mesh:", handle);
+                "MeshHandle index out of range:", handle.index);
-  return *meshes[handle];
+
+  const Slot& slot = slots[handle.index];
+  SOPHIA_ASSERT(slot.generation == handle.generation,
+                "stale MeshHandle (generation mismatch):", handle.index);
+  SOPHIA_ASSERT(slot.mesh != nullptr,
+                "MeshHandle refers to a released mesh:", handle.index);
+  return *slot.mesh;
 }
 
 void MeshPool::release(MeshHandle handle) {
-  SOPHIA_ASSERT(handle < meshes.size(), "invalid MeshHandle:", handle);
+  SOPHIA_ASSERT(handle.isValid(), "invalid MeshHandle");
-  SOPHIA_ASSERT(meshes[handle] != nullptr,
+  SOPHIA_ASSERT(handle.index < slots.size(),
-                "MeshHandle already released:", handle);
+                "MeshHandle index out of range:", handle.index);
 
-  meshes[handle].reset();
+  Slot& slot = slots[handle.index];
-  freeList.push_back(handle);
+  SOPHIA_ASSERT(slot.generation == handle.generation,
+                "stale MeshHandle (generation mismatch):", handle.index);
+  SOPHIA_ASSERT(slot.mesh != nullptr,
+                "MeshHandle already released:", handle.index);
+
+  slot.mesh.reset();
+  slot.generation = (slot.generation + 1) & GENERATION_MASK;
+  freeList.push_back(handle.index);
 }
 
 }  // namespace sophia

engine/src/assets/pools/mesh_pool.hpp

@@ -21,10 +21,15 @@ class MeshPool {
   void release(MeshHandle handle);
 
  private:
+  struct Slot {
+    std::unique_ptr<Mesh> mesh;
+    u32 generation = 0;
+  };
+
   Device& device;
 
-  std::vector<std::unique_ptr<Mesh>> meshes;
+  std::vector<Slot> slots;
-  std::vector<MeshHandle> freeList;
+  std::vector<u32> freeList;
 };
 
 }  // namespace sophia