Merge pull request #72 from devscafecommunity/39-skeletal-animation

feat(script): Lua scripting with sol2, hot-reload, and ECS integration

Author: LyeZinho

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.20)
 
-project(Caffeine VERSION 0.1.0 LANGUAGES CXX)
+project(Caffeine VERSION 0.1.0 LANGUAGES CXX C)
 
 set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
@@ -88,4 +88,92 @@ target_link_libraries(caf-encode PRIVATE Caffeine)
 target_include_directories(caf-encode PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/src)
 target_compile_features(caf-encode PRIVATE cxx_std_20)
 
-add_subdirectory(tests)
+add_subdirectory(tests)
+
+# ── Scripting (Lua + sol2) ────────────────────────────────────
+option(CAFFEINE_ENABLE_SCRIPTING "Enable Lua scripting support" OFF)
+
+if(CAFFEINE_ENABLE_SCRIPTING)
+    include(FetchContent)
+
+    # Build Lua 5.4 from source (sol2 v3.3.0 needs exact 5.4 API)
+    FetchContent_Declare(lua54
+        GIT_REPOSITORY https://github.com/lua/lua.git
+        GIT_TAG v5.4.7
+        GIT_SHALLOW TRUE
+    )
+    FetchContent_GetProperties(lua54)
+    if(NOT lua54_POPULATED)
+        FetchContent_Populate(lua54)
+        set(LUA54_SRC ${lua54_SOURCE_DIR})
+        add_library(lua54 STATIC
+            ${LUA54_SRC}/lapi.c
+            ${LUA54_SRC}/lauxlib.c
+            ${LUA54_SRC}/lbaselib.c
+            ${LUA54_SRC}/lcode.c
+            ${LUA54_SRC}/lcorolib.c
+            ${LUA54_SRC}/lctype.c
+            ${LUA54_SRC}/ldblib.c
+            ${LUA54_SRC}/ldebug.c
+            ${LUA54_SRC}/ldo.c
+            ${LUA54_SRC}/ldump.c
+            ${LUA54_SRC}/lfunc.c
+            ${LUA54_SRC}/lgc.c
+            ${LUA54_SRC}/linit.c
+            ${LUA54_SRC}/liolib.c
+            ${LUA54_SRC}/llex.c
+            ${LUA54_SRC}/lmathlib.c
+            ${LUA54_SRC}/lmem.c
+            ${LUA54_SRC}/loadlib.c
+            ${LUA54_SRC}/lobject.c
+            ${LUA54_SRC}/lopcodes.c
+            ${LUA54_SRC}/loslib.c
+            ${LUA54_SRC}/lparser.c
+            ${LUA54_SRC}/lstate.c
+            ${LUA54_SRC}/lstring.c
+            ${LUA54_SRC}/lstrlib.c
+            ${LUA54_SRC}/ltable.c
+            ${LUA54_SRC}/ltablib.c
+            ${LUA54_SRC}/ltm.c
+            ${LUA54_SRC}/lundump.c
+            ${LUA54_SRC}/lutf8lib.c
+            ${LUA54_SRC}/lvm.c
+            ${LUA54_SRC}/lzio.c
+        )
+        target_include_directories(lua54 BEFORE PUBLIC ${LUA54_SRC})
+        # Create lua.hpp C++ wrapper so sol2's #include <lua.hpp> finds our 5.4 headers
+        file(WRITE ${LUA54_SRC}/lua.hpp
+            "extern \"C\" {\n"
+            "#include \"lua.h\"\n"
+            "#include \"lauxlib.h\"\n"
+            "#include \"lualib.h\"\n"
+            "}\n")
+    endif()
+
+    # sol2 (header-only C++/Lua binding library)
+    set(SOL2_BUILD_LUA OFF)
+    FetchContent_Declare(sol2
+        GIT_REPOSITORY https://github.com/ThePhD/sol2.git
+        GIT_TAG v3.3.0
+        GIT_SHALLOW TRUE
+    )
+    FetchContent_MakeAvailable(sol2)
+
+    # Patch sol2 optional_implementation.hpp for GCC 16+ compatibility
+    execute_process(COMMAND python3 "${CMAKE_CURRENT_SOURCE_DIR}/cmake/patch_sol2_optional.py"
+        "${sol2_SOURCE_DIR}/include/sol/optional_implementation.hpp"
+        RESULT_VARIABLE PATCH_RESULT)
+    if(NOT PATCH_RESULT EQUAL 0)
+        message(FATAL_ERROR "Failed to patch sol2 for GCC 16 compatibility")
+    endif()
+
+    target_link_libraries(Caffeine PRIVATE sol2::sol2 lua54)
+
+    target_compile_definitions(Caffeine PUBLIC CF_HAS_SCRIPTING=1)
+
+    target_sources(Caffeine PRIVATE
+        src/script/ScriptEngine.cpp
+        src/script/ScriptSystem.cpp
+        src/script/ScriptWatcher.cpp
+    )
+endif()

cmake/patch_sol2_optional.py

@@ -0,0 +1,24 @@
+import sys
+
+path = sys.argv[1]
+with open(path) as f:
+    content = f.read()
+
+# Fix 1: optional_base<T> emplace -- this->construct() doesn't set this->m_value correctly
+content = content.replace(
+    '*this = nullopt;\n\t\t\tthis->construct(std::forward<Args>(args)...);\n\t\t\treturn value();',
+    '*this = nullopt;\n\t\t\tthis->m_value = std::addressof((std::forward<Args>(args), ...));\n\t\t\treturn value();')
+
+# Fix 2: optional<T&> emplace -- this->construct() doesn't exist in ref specialization
+content = content.replace(
+    '*this = nullopt;\n\t\t\tthis->construct(std::forward<Args>(args)...);\n\t\t}',
+    '*this = nullopt;\n\t\t\tm_value = std::addressof((std::forward<Args>(args), ...));\n\t\t\treturn *m_value;\n\t\t}')
+
+with open(path, 'w') as f:
+    f.write(content)
+
+remaining = content.count('this->construct(std::forward<Args>(args)')
+if remaining > 0:
+    print(f'WARNING: {remaining} unpatched occurrences remain')
+    sys.exit(1)
+print('sol2 optional_implementation.hpp patched')

src/Caffeine.hpp

@@ -105,6 +105,14 @@
 #endif
 #endif
 
+// Scripting (optional — CAFFEINE_ENABLE_SCRIPTING)
+#ifdef CF_HAS_SCRIPTING
+#include "script/ScriptEngine.hpp"
+#include "script/ScriptTypes.hpp"
+#include "script/ScriptSystem.hpp"
+#include "script/ScriptWatcher.hpp"
+#endif
+
 // Tools (Asset Pipeline)
 #include "tools/PipelineTypes.hpp"
 #include "tools/TextureEncoder.hpp"

src/ecs/World.hpp

@@ -283,4 +283,31 @@ void World::forEachParallel(const ComponentQuery& query, Threading::JobSystem& j
     barrier.wait();
 }
 
+template<typename T, typename... Args>
+T& Entity::add(Args&&... args) {
+    return m_world->add<T>(*this, std::forward<Args>(args)...);
+}
+
+template<typename T>
+void Entity::remove() {
+    m_world->remove<T>(*this);
+}
+
+template<typename T>
+bool Entity::has() const {
+    return m_world->has<T>(*this);
+}
+
+template<typename T>
+T* Entity::get() {
+    return m_world->get<T>(*this);
+}
+
+template<typename T>
+T& Entity::getOrAdd() {
+    T* ptr = m_world->get<T>(*this);
+    if (ptr) return *ptr;
+    return m_world->add<T>(*this);
+}
+
 }

src/input/InputManager.cpp

@@ -130,6 +130,16 @@ AxisState InputManager::axisState(Axis axis) const {
     return state;
 }
 
+bool InputManager::isKeyDown(Key key) const {
+    auto idx = static_cast<usize>(key);
+    return idx < m_keyState.size() && m_keyState[idx];
+}
+
+bool InputManager::isMouseButtonDown(MouseButton button) const {
+    auto idx = static_cast<usize>(button);
+    return idx < m_mouseState.size() && m_mouseState[idx];
+}
+
 Vec2 InputManager::mousePosition() const {
     return m_mousePos;
 }

src/input/InputManager.hpp

@@ -185,6 +185,8 @@ class InputManager {
     // --- Query state ---
     ActionState actionState(Action action) const;
     AxisState   axisState(Axis axis) const;
+    bool        isKeyDown(Key key) const;
+    bool        isMouseButtonDown(MouseButton button) const;
     Vec2        mousePosition() const;
     Vec2        mouseDelta() const;