experiment: Store components in contiguous arrays

.gitignore

@@ -4,6 +4,7 @@ RelWithDebInfo/
 docker/configs
 
 # Third party libraries
+thirdparty/magic_enum
 thirdparty/mysql/
 thirdparty/mysql_linux/
 CMakeVariables.txt

.gitmodules

@@ -14,6 +14,3 @@
 	path = thirdparty/mariadb-connector-cpp
 	url = https://github.com/mariadb-corporation/mariadb-connector-cpp.git
 	ignore = dirty
-[submodule "thirdparty/magic_enum"]
-	path = thirdparty/magic_enum
-	url = https://github.com/Neargye/magic_enum.git

CMakeLists.txt

@@ -110,6 +110,23 @@ set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR})
 
 find_package(MariaDB)
 
+# Fetch third party dependencies
+set(DLU_THIRDPARTY_SOURCE_DIR ${CMAKE_SOURCE_DIR}/thirdparty)
+
+include(FetchContent)
+FetchContent_Declare(
+	magic_enum
+	SYSTEM
+	# SOURCE_DIR     ${DLU_THIRDPARTY_SOURCE_DIR}/magic_enum
+	GIT_REPOSITORY https://github.com/Neargye/magic_enum.git
+	GIT_TAG        v0.9.7
+)
+FetchContent_MakeAvailable(magic_enum)
+
+include(CMakePrintHelpers)
+cmake_print_properties(TARGETS magic_enum::magic_enum PROPERTIES
+                       INTERFACE_INCLUDE_DIRECTORIES)
+
 # Create a /resServer directory
 make_directory(${CMAKE_BINARY_DIR}/resServer)
 
@@ -252,7 +269,6 @@ include_directories(
 	"tests/dGameTests/dComponentsTests"
 
 	SYSTEM
-	"thirdparty/magic_enum/include/magic_enum"
 	"thirdparty/raknet/Source"
 	"thirdparty/tinyxml2"
 	"thirdparty/recastnavigation"
@@ -303,6 +319,7 @@ file(
 # Add our library subdirectories for creation of the library object
 add_subdirectory(dCommon)
 add_subdirectory(dDatabase)
+add_subdirectory(dECS)
 add_subdirectory(dChatFilter)
 add_subdirectory(dNet)
 add_subdirectory(dScripts) # Add for dGame to use
@@ -313,7 +330,7 @@ add_subdirectory(dPhysics)
 add_subdirectory(dServer)
 
 # Create a list of common libraries shared between all binaries
-set(COMMON_LIBRARIES "dCommon" "dDatabase" "dNet" "raknet" "magic_enum")
+set(COMMON_LIBRARIES "dCommon" "dDatabase" "dNet" "raknet" "magic_enum::magic_enum")
 
 # Add platform specific common libraries
 if(UNIX)

dCommon/CMakeLists.txt

@@ -70,5 +70,6 @@ else ()
 endif ()
 
 target_link_libraries(dCommon
+	PUBLIC magic_enum::magic_enum
 	PRIVATE ZLIB::ZLIB bcrypt tinyxml2
 	INTERFACE dDatabase)

dCommon/dEnums/MessageType/Game.h

@@ -1,7 +1,7 @@
 #pragma once
 #include <cstdint>
 
-#include "magic_enum.hpp"
+#include <magic_enum/magic_enum.hpp>
 
 namespace MessageType {
 	enum class Game : uint16_t {

dCommon/dEnums/MessageType/World.h

@@ -1,7 +1,7 @@
 #pragma once
 #include <cstdint>
 
-#include "magic_enum.hpp"
+#include <magic_enum/magic_enum.hpp>
 
 namespace MessageType {
 	enum class World : uint32_t {

dCommon/dEnums/StringifiedEnum.h

@@ -2,7 +2,7 @@
 #define __STRINGIFIEDENUM_H__
 
 #include <string>
-#include "magic_enum.hpp"
+#include <magic_enum/magic_enum.hpp>
 
 namespace StringifiedEnum {
 	template<typename T>

dCommon/dEnums/eInventoryType.h

@@ -5,7 +5,7 @@
 
 #include <cstdint>
 
-#include "magic_enum.hpp"
+#include <magic_enum/magic_enum.hpp>
 
 static const uint8_t NUMBER_OF_INVENTORIES = 17;
 /**

dDatabase/CMakeLists.txt

@@ -2,12 +2,6 @@ add_subdirectory(CDClientDatabase)
 add_subdirectory(GameDatabase)
 
 add_library(dDatabase STATIC "MigrationRunner.cpp")
-
-add_custom_target(conncpp_dylib
-	${CMAKE_COMMAND} -E copy $<TARGET_FILE:MariaDB::ConnCpp> ${PROJECT_BINARY_DIR})
-
-add_dependencies(dDatabase conncpp_dylib)
-
 target_include_directories(dDatabase PUBLIC ".")
 target_link_libraries(dDatabase
-	PUBLIC dDatabaseCDClient dDatabaseGame)
+	PUBLIC magic_enum::magic_enum dDatabaseCDClient dDatabaseGame)

dECS/CMakeLists.txt

@@ -0,0 +1,15 @@
+set(gcc_like_cxx "$<COMPILE_LANG_AND_ID:CXX,ARMClang,AppleClang,Clang,GNU,LCC>")
+set(msvc_cxx "$<COMPILE_LANG_AND_ID:CXX,MSVC>")
+
+add_library(dECS STATIC
+    "Core.h"
+    "Iter.h"
+    "Core.cpp"
+    "System.cpp"
+)
+target_include_directories(dECS PUBLIC .)
+target_link_libraries(dECS PRIVATE dCommon magic_enum::magic_enum)
+target_compile_options(dECS PRIVATE
+  "$<${gcc_like_cxx}:$<BUILD_INTERFACE:-Wall;-Wextra>>"
+  "$<${msvc_cxx}:$<BUILD_INTERFACE:/W3>>"
+)

dECS/Core.cpp

@@ -0,0 +1,70 @@
+#include <atomic>
+#include <magic_enum/magic_enum_containers.hpp>
+#include <eReplicaComponentType.h>
+#include "Core.h"
+
+namespace dECS {
+    struct WorldData {
+        using CompSignature = magic_enum::containers::bitset<eReplicaComponentType>;
+        using CompMap = std::unordered_map<LWOOBJID, CompSignature>;
+        using CompStorage = std::unordered_map<eReplicaComponentType, std::unique_ptr<IStorage>>;
+
+        std::atomic<LWOOBJID> nextId = 1;
+        CompMap map;
+        CompStorage data;
+    };
+
+    World::World() : m_World{ std::make_shared<WorldData>() } {};
+
+    Entity World::MakeEntity() {
+        return Entity{ m_World->nextId.fetch_add(1, std::memory_order::relaxed),
+                       m_World };
+    }
+
+    void* Entity::AddComponent(const eReplicaComponentType kind, const StorageConstructor storageConstructor) {
+        if (auto w = m_World.lock()) {
+            // Add to kind signature
+            w->map[m_Id].set(kind, true);
+
+            // Get or add storage
+            auto storageIt = w->data.find(kind);
+            if (storageIt == w->data.cend()) {
+                bool inserted = false;
+                std::tie(storageIt, inserted) = w->data.try_emplace(kind, storageConstructor());
+                if (!inserted) throw "storage emplacement failure";
+            }
+            auto& storage = *storageIt->second;
+
+            // Return reference if already mapped, otherwise add component
+            auto compIt = storage.rowMap.find(m_Id);
+            if (compIt == storage.rowMap.cend()) {
+                const auto curSize = storage.rowMap.size();
+                storage.rowMap.emplace(m_Id, curSize);
+                return storage.emplace_back();
+            }
+            const auto row = compIt->second;
+            return storage.at(row);
+        }
+        return nullptr;
+    }
+
+    const void* Entity::GetComponent(const eReplicaComponentType kind) const {
+        if (auto const w = m_World.lock()) {
+            // Check that the entity has this component
+            if (!w->map[m_Id].test(kind)) return nullptr;
+
+            // Get the location where it's stored
+            const auto& storage = *w->data.at(kind);
+            const auto it = storage.rowMap.find(m_Id);
+            if (it == storage.rowMap.cend()) return nullptr;
+            const auto row = it->second;
+            return storage.at(row);
+        }
+        return nullptr;
+    }
+
+    void* Entity::GetComponent(const eReplicaComponentType kind) {
+        // Casting away const for this overload is safe, if not at all pretty
+        return const_cast<void*>(std::as_const(*this).GetComponent(kind));
+    }
+}

dECS/Core.h

@@ -0,0 +1,180 @@
+#pragma once
+#include <cstdint>
+#include <memory>
+#include <string_view>
+#include <type_traits>
+#include <unordered_map>
+#include <vector>
+
+class Component;
+enum class eReplicaComponentType : uint32_t;
+using LWOOBJID = int64_t;
+
+namespace dECS {
+    // template <typename C>
+    // concept IsComponent = std::derived_from<C, Component>;
+
+    // Data structures
+    struct WorldData;
+    class World;
+
+    template <typename... Cs>
+    class System;
+
+    class Entity;
+    struct IStorage;
+
+    template <typename C>
+    class Storage;
+
+    using WorldPtr = std::shared_ptr<WorldData>;
+    using WeakWorldPtr = std::weak_ptr<WorldData>;
+
+    class World {
+    public:
+        World();
+
+        [[nodiscard]]
+        Entity MakeEntity();
+
+        template <typename... Cs>
+        [[nodiscard]]
+        System<Cs...> MakeSystem() {
+            return System<Cs...>{};
+        }
+
+        template <typename... Cs, typename S>
+        [[nodiscard]]
+        System<Cs...> MakeSystem(S&& name) {
+            return System<Cs...>{ std::forward<S>(name) };
+        }
+
+    private:
+        WorldPtr m_World;
+    };
+
+    template <typename... Cs>
+    class System {
+    public:
+        friend System World::MakeSystem<Cs...>();
+
+        template <typename... Ts, typename S>
+        friend System<Ts...> World::MakeSystem(S&&);
+
+        /*template <typename Fn>
+            requires std::is_invocable_r_v<void, Fn(Cs...), ObjId, Cs...>
+        void ForEach(Fn&& f) {
+            for (ObjId i = 0; i < mT.size(); ++i) {
+                auto& c = mT[i];
+                f(i, std::get<Cs>(c)...);
+            }
+        }*/
+
+        template <typename Fn>
+            requires std::is_invocable_r_v<void, Fn(Cs...), Cs...>
+        void ForEach(Fn&& fn) {
+            std::tuple<Cs...> comps; // some sort of iterator that returns a tuple each 'step?'
+            for (size_t i = 0; i < 5; ++i) {
+                fn(std::get<Cs>(comps)...);
+            }
+        }
+
+    private:
+        System() = default;
+
+        template <typename S>
+        explicit System(S&& name)
+            : m_name{ std::forward<S>(name) }
+        {}
+
+        std::string m_name;
+    };
+
+    class Entity {
+    public:
+        friend Entity World::MakeEntity();
+
+        using StorageConstructor = std::function<std::unique_ptr<IStorage>()>;
+
+        [[nodiscard]]
+        constexpr LWOOBJID GetObjectID() const noexcept {
+            return m_Id;
+        }
+
+        [[maybe_unused]]
+        void* AddComponent(eReplicaComponentType, StorageConstructor);
+
+        template <typename C>
+        [[maybe_unused]]
+        C* AddComponent() {
+            return static_cast<C*>(AddComponent(C::ComponentType, std::make_unique<Storage<C>>));
+        }
+
+        [[nodiscard]]
+        const void* GetComponent(eReplicaComponentType) const;
+
+        [[nodiscard]]
+        void* GetComponent(eReplicaComponentType);
+
+        template <typename C>
+        [[nodiscard]]
+        const C* GetComponent() const {
+            return static_cast<const C*>(GetComponent(C::ComponentType));
+        }
+
+        template <typename C>
+        [[nodiscard]]
+        C* GetComponent() {
+            return static_cast<C*>(GetComponent(C::ComponentType));
+        }
+
+    private:
+        Entity(const LWOOBJID id, const WeakWorldPtr world)
+            : m_Id{ id }
+            , m_World { world }
+            {}
+
+        LWOOBJID m_Id;
+
+        WeakWorldPtr m_World;
+    };
+
+    struct IStorage {
+        using RowMap = std::unordered_map<LWOOBJID, size_t>;
+
+        virtual ~IStorage() = default;
+
+        [[nodiscard]]
+        virtual void* at(size_t) = 0;
+
+        [[nodiscard]]
+        virtual const void* at(size_t) const = 0;
+
+        [[nodiscard]]
+        virtual void* emplace_back() = 0;
+
+        RowMap rowMap;
+    };
+
+    template <typename C>
+    class Storage : public IStorage {
+    public:
+        [[nodiscard]]
+        void* at(const size_t index) override {
+            return static_cast<void*>(&m_Vec.at(index));
+        }
+
+        [[nodiscard]]
+        const void* at(const size_t index) const override {
+            return static_cast<const void*>(&m_Vec.at(index));
+        }
+
+        [[nodiscard]]
+        void* emplace_back() override {
+            return static_cast<void*>(&m_Vec.emplace_back());
+        }
+
+    private:
+        std::vector<C> m_Vec;
+    };
+}