make polymorphic component storage type

CMakeLists.txt

@@ -303,6 +303,7 @@ 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

dECS/CMakeLists.txt

@@ -0,0 +1,4 @@
+add_library(dECS STATIC "ECS.cpp")
+target_include_directories(dECS PUBLIC .)
+target_link_libraries(dECS PRIVATE dCommon)
+target_compile_options(dECS PRIVATE "-Wall")

dECS/ECS.cpp

@@ -0,0 +1,8 @@
+#include "ECS.h"
+#include "dCommonVars.h"
+#include <string>
+#include <vector>
+
+namespace Component {
+
+}

dECS/ECS.h

@@ -0,0 +1,65 @@
+#pragma once
+#include <bitset>
+#include <climits>
+#include <cstdint>
+#include <vector>
+#include "dCommonVars.h"
+#include "eReplicaComponentType.h"
+
+namespace Component {
+    constexpr size_t MAX_KINDS { 32 };
+
+    enum class Kind : uint32_t {
+        NONE = 0,
+        DESTROYABLE = 7,
+        PET = 26,
+    };
+
+    using Signature = std::bitset<MAX_KINDS>;
+
+    // Components
+    struct Destroyable;
+    struct Pet {
+        static constexpr Kind KIND_ID = Kind::PET;
+
+        // The ID under which this pet is stored in the database (if it's tamed)
+        LWOOBJID m_DatabaseId;
+
+        // The ID of the item from which this pet was creat
+        LWOOBJID m_ItemId;
+
+        // The name of this pet
+        std::string name;
+    };
+
+    class IStorage {
+    public:
+        constexpr IStorage(const Kind kind) : m_Kind{ kind } {}
+        virtual ~IStorage() = default;
+        constexpr virtual void Remove(const size_t index) = 0;
+
+        [[nodiscard]]
+        constexpr Kind GetKind() const {
+            return m_Kind;
+        }
+
+    protected:
+        Kind m_Kind;
+    };
+
+    template <typename C>
+    class Storage : public IStorage {
+    public:
+        constexpr Storage() : IStorage{ C::KIND_ID } {}
+
+        constexpr void Remove(const size_t index) override {
+            auto& elementToDelete = m_Vec.at(index);
+            auto& lastElement = m_Vec.back();
+            std::swap(elementToDelete, lastElement);
+            m_Vec.pop_back();
+        }
+
+    private:
+        std::vector<C> m_Vec;
+    };
+}

tests/CMakeLists.txt

@@ -6,4 +6,5 @@ include(GoogleTest)
 
 # Add the subdirectories
 add_subdirectory(dCommonTests)
+add_subdirectory(dECSTests)
 add_subdirectory(dGameTests)

tests/dECSTests/CMakeLists.txt

@@ -0,0 +1,9 @@
+add_executable(dECSTests
+    "TestECS.cpp"
+)
+
+# Link needed libraries
+target_link_libraries(dECSTests PRIVATE dCommon dECS GTest::gtest_main)
+
+# Discover the tests
+gtest_discover_tests(dECSTests)

tests/dECSTests/TestECS.cpp

@@ -0,0 +1,10 @@
+#include <gtest/gtest.h>
+#include "ECS.h"
+
+TEST(ECSTest, MakeStorage) {
+    const auto storage = Component::Storage<Component::Pet>();
+    const Component::IStorage* const storagePtr = &storage;
+
+    ASSERT_EQ(storagePtr->GetKind(), Component::Kind::PET);
+    ASSERT_NE(storagePtr->GetKind(), Component::Kind::DESTROYABLE);
+}