Incomplete Index Component System (ICS)

sim/CMakeLists.txt

@@ -4,8 +4,17 @@ project(bentobox)
 # Source files
 set(SRC_DIR "${CMAKE_CURRENT_SOURCE_DIR}/src")
 set(LIB_DIR "${CMAKE_CURRENT_SOURCE_DIR}/lib")
-set(SOURCES "${SRC_DIR}/main.cpp")
-set(TESTS "${SRC_DIR}/test.cpp")
+set(ICS_DIR "${SRC_DIR}/ics")
+set(UTIL_DIR "${SRC_DIR}/util")
+
+set(SOURCES
+    "${SRC_DIR}/main.cpp"
+    "${SRC_DIR}/ICSManager.h"
+)
+
+set(TESTS
+    "${SRC_DIR}/main.test.cpp"
+)
 
 # Executable
 set(CMAKE_CXX_STANDARD 20)
@@ -14,6 +23,13 @@ add_executable(${PROJECT_NAME} ${SOURCES})
 add_executable("${PROJECT_NAME}_test" ${TESTS})
 target_include_directories(${PROJECT_NAME} PRIVATE ${SRC_DIR})
 
+# Link libraries
+foreach (lib IN ITEMS util ics)
+    add_subdirectory("${SRC_DIR}/${lib}")
+    target_link_libraries(${PROJECT_NAME} PRIVATE ${lib})
+    target_link_libraries(${PROJECT_NAME}_test PRIVATE -Wl,--whole-archive ${lib}-test -Wl,--no-whole-archive)
+endforeach()
+
 ## Dependencies
 # GLFW
 find_package(glfw3 3 REQUIRED)
@@ -37,7 +53,8 @@ endif(NOT WIN32)
 ## Test Dependencies
 # Google test
 add_subdirectory(
-    "${LIB_DIR}/googletest/googletest"
-    "${LIB_DIR}/googletest/googlemock"
-    EXCLUDE_FROM_ALL)
+    "${LIB_DIR}/googletest"
+    EXCLUDE_FROM_ALL
+)
+
 target_link_libraries("${PROJECT_NAME}_test" PRIVATE gtest_main)

sim/src/ICSManager.h

@@ -0,0 +1,46 @@
+#ifndef BENTOBOX_ICSMANAGER_H
+#define BENTOBOX_ICSMANAGER_H
+
+#include <memory>
+#include <ics/index.h>
+#include <ics/component.h>
+#include <ics/compVec.h>
+#include <util/typeMap.h>
+
+namespace {
+    template<ics::Component C>
+    using CompContainer = ics::CompVec<C>;
+}
+
+class ICSManager {
+private:
+    std::unique_ptr<util::TypeMap> indexes;
+    std::unique_ptr<util::TypeMap> components;
+public:
+    template<ics::Component C>
+    void addComponent(C c) {
+        if (components->has<CompContainer<C>>()) {
+            // The container already exists
+            // TODO: test that this actually updates the container value
+            auto container = components->at<CompContainer<C>>();
+            container.add(c);
+        } else {
+            // The container does not exist
+            auto container = CompContainer<C>();
+            container.add(c);
+            components->insert(container);
+        }
+    }
+
+    template<ics::Component C, ics::Index I>
+    void addIndex(I i) {
+        if (indexes->has<I>()) {
+            // TODO: Make a better error
+            throw std::logic_error("ICSManager::addIndex: attempting to replace existing index");
+        } else {
+            indexes->insert(i);
+        }
+    }
+};
+
+#endif //BENTOBOX_ICSMANAGER_H

sim/src/ics/CMakeLists.txt

@@ -0,0 +1,25 @@
+SET(LIB_NAME ics)
+SET(SOURCES component.h compVec.h index.h)
+SET(TESTS component.test.cpp compVec.test.cpp index.test.cpp)
+
+add_library(
+    ${LIB_NAME}
+    ${SOURCES}
+)
+
+add_library(
+    ${LIB_NAME}-test
+    ${SOURCES}
+    ${TESTS}
+)
+
+# Cmake could not determine the language used from the files
+# https://stackoverflow.com/questions/11801186/cmake-unable-to-determine-linker-language-with-c
+set_target_properties(${LIB_NAME} PROPERTIES LINKER_LANGUAGE CXX)
+set_target_properties(${LIB_NAME}-test PROPERTIES LINKER_LANGUAGE CXX)
+
+target_include_directories(${LIB_NAME} PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}")
+target_include_directories(${LIB_NAME}-test PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}")
+
+# Google test
+target_link_libraries("${LIB_NAME}-test" PRIVATE gtest)

sim/src/ics/compVec.h

@@ -0,0 +1,76 @@
+#ifndef BENTOBOX_COMPVEC_H
+#define BENTOBOX_COMPVEC_H
+
+#include <vector>
+#include <queue>
+#include <memory>
+#include <typeindex>
+#include <iostream>
+
+#include "component.h"
+
+namespace ics {
+    template<Component C>
+    class CompVec {
+    public:
+        typedef typename std::vector<C>::size_type size_type;
+    private:
+        std::unique_ptr<std::queue<size_type>> inactiveCompIdx = std::make_unique<std::queue<size_type>>();
+        std::unique_ptr<std::vector<C>> vecPtr = std::make_unique<std::vector<C>>();
+    protected:
+        void isActiveCheck(size_type idx) const;
+    public:
+        size_type add(const C& val);
+        void remove(size_type idx);
+
+        C& at(size_type idx) const;
+        C& operator[](size_type idx);
+        const C& operator[](size_type idx) const;
+    };
+
+    template<Component C>
+    void CompVec<C>::isActiveCheck(size_type idx) const {
+        if (!this->vecPtr->at(idx).isActive) {
+            // TODO: format the index into the string
+            throw std::out_of_range("compVec::isActiveCheck: component at index is inactive");
+        }
+    }
+
+    template<Component C>
+    typename CompVec<C>::size_type CompVec<C>::add(const C& val) {
+        if (!this->inactiveCompIdx->empty()) {
+            // Reuse old component space
+            CompVec<C>::size_type insertIdx = this->inactiveCompIdx->front();
+            this->vecPtr->at(insertIdx) = val;
+            this->inactiveCompIdx->pop();
+            return insertIdx;
+        } else {
+            this->vecPtr->push_back(val);
+        }
+    }
+
+    template<Component C>
+    void CompVec<C>::remove(size_type idx) {
+        // Mark component as deleted
+        this->vecPtr->at(idx).isActive = false;
+        this->inactiveCompIdx->push(idx);
+    }
+
+    template<Component C>
+    C& CompVec<C>::at(CompVec<C>::size_type idx) const {
+        this->isActiveCheck(idx);
+        return this->vecPtr->at(idx);
+    }
+
+    template<Component C>
+    const C& CompVec<C>::operator[](size_type idx) const {
+        return this->at(idx);
+    }
+
+    template<Component C>
+    C& CompVec<C>::operator[](size_type idx) {
+        return this->at(idx);
+    }
+}
+
+#endif //BENTOBOX_COMPVEC_H

sim/src/ics/compVec.test.cpp

@@ -0,0 +1,62 @@
+#include <gtest/gtest.h>
+#include "component.h"
+#include "compVec.h"
+
+#define TEST_SUITE CompVecTest
+
+using namespace ics;
+
+struct TestComp : public DefaultComponent {
+    int height;
+};
+
+TEST(TEST_SUITE, StoreAndRetrieve) {
+    auto vec = CompVec<TestComp>();
+    vec.add(TestComp { true, 3 });
+
+    TestComp value = vec.at(0);
+    ASSERT_EQ(value.height, 3);
+}
+
+TEST(TEST_SUITE, RetrieveNonExistentComponent) {
+    auto vec = CompVec<TestComp>();
+    EXPECT_THROW(
+        vec.at(0),
+        std::out_of_range
+    );
+}
+
+TEST(TEST_SUITE, ReuseDeletedComponent) {
+    auto vec = CompVec<TestComp>();
+
+    // Create two elements
+    auto firstElementIdx = vec.add(TestComp{ true, 3 });
+    vec.add(TestComp{ true, 3 });
+
+    // Remove the first
+    vec.remove(firstElementIdx);
+
+    // The first element's memory location should be reused
+    auto newElement = TestComp { true, 3 };
+    auto newInsertIndex = vec.add(newElement);
+    ASSERT_EQ(firstElementIdx, newInsertIndex);
+
+    // The values should be the newly inserted component's values
+    ics::Component auto firstElement = vec.at(firstElementIdx);
+    ASSERT_EQ(firstElement, newElement);
+    ASSERT_EQ(firstElement.height, 3);
+}
+
+TEST(TEST_SUITE, RetrieveDeletedComponent) {
+    auto vec = CompVec<TestComp>();
+    auto idx = vec.add(TestComp{ true, 3 });
+    vec.remove(idx);
+    EXPECT_THROW(
+        vec.at(idx),
+        std::out_of_range
+    );
+    EXPECT_THROW(
+        vec[idx],
+        std::out_of_range
+    );
+}

sim/src/ics/component.h

@@ -0,0 +1,30 @@
+#ifndef BENTOBOX_COMPONENT_H
+#define BENTOBOX_COMPONENT_H
+
+#include <concepts>
+
+namespace ics {
+    template<class T>
+    concept Component = std::semiregular<T>
+            && std::same_as<decltype(T::isActive), bool>;
+
+    // Needed for Index concept
+    // See: https://stackoverflow.com/q/37655113/4428725
+    namespace archetypes {
+        struct Component {
+            bool isActive = true;
+            bool operator==(const Component&) const = default;
+        };
+    }
+
+    static_assert(Component<archetypes::Component>);
+
+    struct DefaultComponent {
+        bool isActive = true;
+        bool operator==(const DefaultComponent&) const = default;
+    };
+
+    static_assert(Component<DefaultComponent>);
+}
+
+#endif //BENTOBOX_COMPONENT_H

sim/src/ics/component.test.cpp

@@ -0,0 +1,40 @@
+#include <gtest/gtest.h>
+#include "component.h"
+
+#define TEST_SUITE Component
+
+using namespace ics;
+
+TEST(TEST_SUITE, DefaultComponentFulfillsConcept) {
+    ASSERT_TRUE(Component<DefaultComponent>);
+}
+
+struct IncorrectNoIsactiveComponent {
+    bool operator==(const IncorrectNoIsactiveComponent&) const = default;
+};
+
+TEST(TEST_SUITE, RequireIsactive) {
+    ASSERT_FALSE(Component<IncorrectNoIsactiveComponent>);
+}
+
+struct DerivedComp : public DefaultComponent {
+    int height;
+    char c;
+};
+
+TEST(TEST_SUITE, DerivedComponentsEquivalence) {
+    auto d1 = DerivedComp {
+        .height = 3,
+        .c = 'c',
+    };
+
+    auto d2 = DerivedComp {
+        .height = 3,
+        .c = 'c',
+    };
+
+    auto d3 = d1;
+
+    ASSERT_EQ(d1, d2);
+    ASSERT_EQ(d3, d1);
+}

sim/src/ics/index.h

@@ -0,0 +1,14 @@
+#ifndef BENTOBOX_INDEX_H
+#define BENTOBOX_INDEX_H
+
+#include "component.h"
+
+namespace ics {
+    template<class T>
+    concept Index = requires(T a, archetypes::Component c) {
+        { a.template addComponent(c) } -> std::same_as<void>;
+        { a.template removeComponent(c) } -> std::same_as<void>;
+    };
+}
+
+#endif //BENTOBOX_INDEX_H

sim/src/ics/index.test.cpp

@@ -0,0 +1,45 @@
+#include <gtest/gtest.h>
+#include "component.h"
+#include "index.h"
+
+#define TEST_SUITE Index
+
+using namespace ics;
+
+class CorrectIndex {
+public:
+    template<Component C>
+    void addComponent(C c) {};
+
+    template<Component C>
+    void removeComponent(C c) {};
+};
+
+TEST(TEST_SUITE, HasAddAndRemoveComponent) {
+    ASSERT_TRUE(Index<CorrectIndex>);
+}
+
+class IncorrectUnconstrainedIndex {
+public:
+    template<typename C>
+    void addComponent(C c) {};
+
+    template<typename C>
+    void removeComponent(C c) {};
+};
+
+TEST(TEST_SUITE, DISABLED_DisallowsUnconstrainedTypenames) {
+    ASSERT_FALSE(Index<IncorrectUnconstrainedIndex>);
+}
+
+template<Component C>
+class IncorrectNoTemplateMethodsIndex {
+public:
+    void addComponent(C c) {};
+
+    void removeComponent(C c) {};
+};
+
+TEST(TEST_SUITE, DisallowsNonTemplateMethods) {
+    ASSERT_FALSE(Index<IncorrectNoTemplateMethodsIndex<DefaultComponent>>);
+}