IrredenEngine: Skill for Claude Code

Lua Creation Setup

LuaJIT 2.1 + sol2. C++ registers systems and pipelines; Lua drives entity creation, configuration, and game logic. Bindings register before IREngine::init. The API reference for everything below is engine/script/CLAUDE.md; this skill is the procedure.

Two paths, often combined, sharing one ComponentId space and archetype graph:

1. Expose C++ types to Lua — lua_bindings.cpp + lua_component_pack.hpp (Part A).
2. Define components and systems in Lua — IRComponent.register / IRSystem.registerSystem, emitted as C++ at build time (CODEGEN) or registered at runtime (EVAL) (Part B).

Files

creations/<category>/<name>/: main_lua.cpp (registerLuaBindings → init → loop), lua_bindings.{hpp,cpp}, lua_component_pack.hpp, config.lua, main.lua (dofiles scripts/). A codegen creation also runs irreden_lua_codegen() on its .lua schema from CMakeLists.txt. Minimum file set and asset staging: creations/CLAUDE.md.

Part A — exposing C++ types

lua_bindings.hpp

#ifndef CREATIONS_MYCREATION_LUA_BINDINGS_H
#define CREATIONS_MYCREATION_LUA_BINDINGS_H

namespace MyCreation {
void registerLuaBindings();
}

#endif

lua_bindings.cpp

#include "lua_bindings.hpp"
#include "lua_component_pack.hpp"

#include <irreden/ir_engine.hpp>
#include <irreden/ir_audio.hpp>

namespace MyCreation {
void registerLuaBindings() {
    static bool isRegistered = false;
    if (isRegistered) return;

    IREngine::registerLuaBindings([](IRScript::LuaScript &luaScript) {
        using namespace IRMath;
        using namespace IRComponents;

        luaScript.registerType<Color, Color(int, int, int, int)>(
            "Color", "r", &Color::red_, "g", &Color::green_,
            "b", &Color::blue_, "a", &Color::alpha_
        );
        luaScript.registerType<ivec3, ivec3(int, int, int)>(
            "ivec3", "x", &ivec3::x, "y", &ivec3::y, "z", &ivec3::z
        );

        luaScript.registerEnum<IREasingFunctions>(
            "IREasingFunction",
            {{"LINEAR_INTERPOLATION", kLinearInterpolation},
             {"QUADRATIC_EASE_IN", kQuadraticEaseIn}}
        );

        registerLuaComponentPack(luaScript);

        luaScript.registerCreateEntityFunction<C_MidiSequence>("createMidiSequence");
        luaScript.registerCreateEntityBatchFunction<
            C_Position3D, C_VoxelSetNew, C_PeriodicIdle>(
            "createEntityBatchVoxelPeriodicIdle"
        );

        luaScript.lua()["IRAudio"] = luaScript.lua().create_table();
        luaScript.lua()["IRAudio"]["openMidiOut"] = [](const std::string &name) {
            return IRAudio::openPortMidiOut(name);
        };
    });

    isRegistered = true;
}
} // namespace MyCreation