update

Author: mingqian.gui

engine/engine/nickel/ecs/entity.hpp

@@ -12,6 +12,8 @@ struct NullEntity final {
     bool operator==(const Entity&) const noexcept;
     bool operator!=(const Entity&) const noexcept;
 
+    operator Entity() const noexcept;
+
 private:
     // entity is null when all used bits are 1
     static constexpr EntityUnderlyingType null_entity_id =

engine/engine/nickel/ecs/world.hpp

@@ -1,14 +1,40 @@
 #pragma once
+#include "nickel/ecs/internal/entity_operations.hpp"
 #include "nickel/ecs/archetype.hpp"
 #include "nickel/ecs/internal/sparse_set.hpp"
 
 namespace nickel::ecs {
 
+struct EntitySparseSetPolicy {
+    using key_type = Entity;
+    using value_type = std::shared_ptr<Record>;
+
+    size_t GetIndexFromKey(const key_type& key) const noexcept {
+        return EntityGetID(key);
+    }
+
+    size_t GetIndexFromValue(const value_type& value) const noexcept {
+        return value->m_dense;
+    }
+
+    Entity GetInvalidKey() const noexcept { return null_entity; }
+
+    value_type GetInvalidValue() const noexcept { return nullptr; }
+
+    void RecordDenseIndex(value_type& value, size_t idx) noexcept {
+        value->m_dense = idx;
+    }
+
+    void ReuseKey(key_type& key) noexcept {
+        // make next generation key
+    }
+};
+
 class World {
 public:
 private:
     std::shared_ptr<Table> m_root_table;
-    // SparseSet<Entity, std::shared_ptr<Record>> m_records;
+    SparseSet<Entity, std::shared_ptr<Record>, EntitySparseSetPolicy> m_records;
 };
 
 }

engine/engine/src/ecs/entity.cpp

@@ -19,6 +19,10 @@ bool NullEntity::operator!=(const Entity& e) const noexcept {
     return !(*this == e);
 }
 
+NullEntity::operator Entity() const noexcept {
+    return static_cast<Entity>(null_entity_id);
+}
+
 bool operator==(Entity e, NullEntity n) {
     return n == e;
 }