Redesign entity-component system

build/pomdog/CMakeLists.txt

@@ -373,14 +373,12 @@ set(POMDOG_SOURCES_CORE
 )
 
 set(POMDOG_SOURCES_EXPERIMENTAL_ECS
-  ${POMDOG_DIR}/include/Pomdog/Experimental/ECS/Component.hpp
+  ${POMDOG_DIR}/include/Pomdog/Experimental/ECS/ComponentBuffer.hpp
+  ${POMDOG_DIR}/include/Pomdog/Experimental/ECS/ComponentType.hpp
   ${POMDOG_DIR}/include/Pomdog/Experimental/ECS/Entity.hpp
-  ${POMDOG_DIR}/include/Pomdog/Experimental/ECS/EntityContext.hpp
-  ${POMDOG_DIR}/include/Pomdog/Experimental/ECS/EntityID.hpp
   ${POMDOG_DIR}/include/Pomdog/Experimental/ECS/EntityManager.hpp
   ${POMDOG_DIR}/include/Pomdog/Experimental/ECS/ComponentTypeIndex.hpp
   ${POMDOG_DIR}/src/Experimental/ECS/Entity.cpp
-  ${POMDOG_DIR}/src/Experimental/ECS/EntityContext.cpp
   ${POMDOG_DIR}/src/Experimental/ECS/EntityManager.cpp
   ${POMDOG_DIR}/src/Experimental/ECS/ComponentTypeIndex.cpp
 )

include/Pomdog/Experimental/ECS/ComponentBuffer.hpp

@@ -0,0 +1,52 @@
+// Copyright (c) 2013-2019 mogemimi. Distributed under the MIT license.
+
+#pragma once
+
+#include "Pomdog/Utility/Assert.hpp"
+#include <cstddef>
+#include <cstdint>
+#include <vector>
+
+namespace Pomdog::ECS::Detail {
+
+class ComponentBufferBase {
+public:
+    virtual ~ComponentBufferBase() = default;
+
+    [[nodiscard]] virtual std::size_t GetSize() const noexcept = 0;
+
+    virtual void Resize(std::size_t size) = 0;
+
+    virtual void Reset(std::uint32_t index) = 0;
+};
+
+template <typename TComponent>
+class ComponentBuffer final : public ComponentBufferBase {
+public:
+    std::size_t GetSize() const noexcept override
+    {
+        return components.size();
+    }
+
+    void Resize(std::size_t size) override
+    {
+        components.resize(size);
+    }
+
+    void Reset(std::uint32_t index) override
+    {
+        POMDOG_ASSERT(index < components.size());
+        components[index] = TComponent{};
+    }
+
+    [[nodiscard]] TComponent* GetComponent(std::uint32_t index)
+    {
+        POMDOG_ASSERT(index < components.size());
+        return &components[index];
+    }
+
+private:
+    std::vector<TComponent> components;
+};
+
+} // namespace Pomdog::ECS::Detail

include/Pomdog/Experimental/ECS/ComponentType.hpp

@@ -0,0 +1,52 @@
+// Copyright (c) 2013-2019 mogemimi. Distributed under the MIT license.
+
+#pragma once
+
+#include "Pomdog/Experimental/ECS/ComponentBuffer.hpp"
+#include "Pomdog/Experimental/ECS/ComponentTypeIndex.hpp"
+#include <cstdint>
+#include <memory>
+#include <string>
+
+namespace Pomdog::ECS {
+
+class ComponentTypeBase {
+public:
+    virtual ~ComponentTypeBase() = default;
+
+    [[nodiscard]] virtual std::uint8_t
+    GetTypeIndex() const noexcept = 0;
+
+    [[nodiscard]] virtual std::unique_ptr<Detail::ComponentBufferBase>
+    CreateComponentBuffer() const = 0;
+};
+
+template <typename TComponent>
+struct ComponentTypeDeclaration final {
+    static std::uint8_t GetTypeIndex()
+    {
+        return Detail::ComponentTypeIndex::Index<TComponent>();
+    }
+};
+
+template <typename T>
+class ComponentType final : public ComponentTypeBase {
+public:
+    std::uint8_t GetTypeIndex() const noexcept override
+    {
+        return ComponentTypeDeclaration<T>::GetTypeIndex();
+    }
+
+    std::unique_ptr<Detail::ComponentBufferBase> CreateComponentBuffer() const override
+    {
+        return std::make_unique<Detail::ComponentBuffer<T>>();
+    }
+};
+
+template <class TComponent, typename... Args>
+inline std::shared_ptr<ComponentTypeBase> AddComponent(Args &&... args)
+{
+    return std::make_shared<ComponentType<TComponent>>(std::forward<Args>(args)...);
+}
+
+} // namespace Pomdog::ECS

include/Pomdog/Experimental/ECS/ComponentTypeIndex.hpp

@@ -6,13 +6,11 @@
 #include <limits>
 #include <type_traits>
 
-namespace Pomdog {
-namespace Detail {
-namespace Gameplay {
+namespace Pomdog::ECS::Detail {
 
 class ComponentTypeIndex {
 public:
-    typedef std::uint8_t IndexType;
+    using IndexType = std::uint8_t;
 
     template <class TComponent>
     static IndexType Index()
@@ -31,6 +29,4 @@ class ComponentTypeIndex {
     static IndexType count;
 };
 
-} // namespace Gameplay
-} // namespace Detail
-} // namespace Pomdog
+} // namespace Pomdog::ECS::Detail

include/Pomdog/Experimental/ECS/Entity.hpp

@@ -2,74 +2,66 @@
 
 #pragma once
 
-#include "Pomdog/Experimental/ECS/EntityContext.hpp"
-#include "Pomdog/Experimental/ECS/EntityID.hpp"
-#include "Pomdog/Utility/Assert.hpp"
-#include <algorithm>
 #include <cstdint>
-#include <memory>
-#include <type_traits>
-#include <utility>
+#include <functional>
 
-namespace Pomdog {
+namespace Pomdog::ECS {
 
 class Entity final {
 public:
-    Entity() = default;
+    constexpr Entity() noexcept
+        : id(0)
+    {
+    }
+
+    constexpr Entity(std::uint32_t sequenceNumber, std::uint32_t index) noexcept
+        : id((static_cast<std::uint64_t>(sequenceNumber) << 32) | (index & 0xffffffffUL))
+    {
+    }
+
+    [[nodiscard]] std::uint32_t GetVersion() const noexcept
+    {
+        return id >> 32;
+    }
+
+    [[nodiscard]] std::uint32_t GetIndex() const noexcept
+    {
+        return id & 0xffffffffUL;
+    }
+
+    [[nodiscard]] std::uint64_t GetUInt64Value() const noexcept
+    {
+        return id;
+    }
+
+    [[nodiscard]] bool operator==(const Entity& other) const noexcept
+    {
+        return id == other.id;
+    }
+
+    [[nodiscard]] bool operator!=(const Entity& other) const noexcept
+    {
+        return id != other.id;
+    }
+
+    [[nodiscard]] bool operator<(const Entity& other) const noexcept
+    {
+        return id < other.id;
+    }
+
+    static const Entity Null;
 
-    Entity(EntityContext* context, const EntityID& id) noexcept;
-
-    explicit operator bool() const noexcept;
-
-    bool operator==(const Entity& entity) const noexcept;
-    bool operator!=(const Entity& entity) const noexcept;
-
-    EntityID GetID() const noexcept;
-
-    template <typename T>
-    std::shared_ptr<T> GetComponent() const;
-
-    template <typename T>
-    std::shared_ptr<T> GetComponent();
-
-    template <typename T>
-    bool HasComponent() const;
+private:
+    std::uint64_t id;
+};
 
-    void Destroy();
+} // namespace Pomdog::ECS
 
-    void DestroyImmediate();
+namespace std {
 
-private:
-    // NOTE: This pointer should be weak or raw pointer instead of shared_ptr.
-    EntityContext* context = nullptr;
-    EntityID id;
+template <>
+struct hash<Pomdog::ECS::Entity> {
+    std::size_t operator()(const Pomdog::ECS::Entity& key) const noexcept;
 };
 
-template <typename T>
-std::shared_ptr<T> Entity::GetComponent() const
-{
-    static_assert(std::is_base_of<Component, T>::value, "");
-    POMDOG_ASSERT(context != nullptr);
-    POMDOG_ASSERT(context->Valid(id));
-    return context->GetComponent<T>(id);
-}
-
-template <typename T>
-std::shared_ptr<T> Entity::GetComponent()
-{
-    static_assert(std::is_base_of<Component, T>::value, "");
-    POMDOG_ASSERT(context != nullptr);
-    POMDOG_ASSERT(context->Valid(id));
-    return context->GetComponent<T>(id);
-}
-
-template <typename T>
-bool Entity::HasComponent() const
-{
-    static_assert(std::is_base_of<Component, T>::value, "");
-    POMDOG_ASSERT(context != nullptr);
-    POMDOG_ASSERT(context->Valid(id));
-    return context->HasComponent<T>(id);
-}
-
-} // namespace Pomdog
+} // namespace std