Add initial prototyped Lua scripting support

applications/testbed/src/Main.cpp

@@ -2,47 +2,50 @@
 #include <cerlib/Main.hpp>
 #include <imgui.h>
 
-class Testbed : public cer::Game
-{
-  public:
-    Testbed()
-    {
-        window = cer::Window{"Testbed"};
-    }
+using namespace cer;
+
+static constexpr auto game_code = R"(
+local anim = 0.0
+local img = Image('logo.png')
+
+function update()
+    anim = anim + time.elapsed_time * 20
+end
 
+function draw()
+    draw_sprite_simple(img, Vector2(100 + anim, 200), white)
+end
+)"_lua;
+
+struct Testbed : Game
+{
     void load_content() override
     {
+        lua_state = LuaState{LuaLibraries::All,
+                             {
+                                 LuaScript{"SomeGameCode", game_code},
+                             }};
     }
 
-    bool update(const cer::GameTime& time) override
+    auto update(const GameTime& time) -> bool override
     {
-        return true;
-    }
+        lua_state.set_variable("time", time);
+        lua_state.run_code("update()");
 
-    void draw(const cer::Window& window) override
-    {
+        return !lua_state.variable_as<bool>("should_exit").value_or(false);
     }
 
-    void draw_imgui(const cer::Window& window) override
+    void draw(const Window& window) override
     {
-        // Enable as you wish:
-#if false
-        ImGui::Begin("My ImGui Window");
-        ImGui::Text("Hello World!");
-
-        if (ImGui::Button("Click here"))
-        {
-            cer::log_info("Button was clicked!");
-        }
-
-        ImGui::End();
-#endif
+        lua_state.set_variable("window", window);
+        lua_state.run_code("draw()");
     }
 
-    cer::Window window;
+    Window   window{"Testbed"};
+    LuaState lua_state;
 };
 
-int main(int argc, char* argv[])
+int main([[maybe_unused]] int argc, [[maybe_unused]] char* argv[])
 {
     return cer::run_game<Testbed>();
 }

include/cerlib.hpp

@@ -28,6 +28,8 @@
 #include <cerlib/KeyModifier.hpp>
 #include <cerlib/List.hpp>
 #include <cerlib/Logging.hpp>
+#include <cerlib/LuaScript.hpp>
+#include <cerlib/LuaState.hpp>
 #include <cerlib/Math.hpp>
 #include <cerlib/Matrix.hpp>
 #include <cerlib/MouseButton.hpp>

include/cerlib/LuaScript.hpp

@@ -0,0 +1,45 @@
+// Copyright (C) 2023-2024 Cemalettin Dervis
+// This file is part of cerlib.
+// For conditions of distribution and use, see copyright notice in LICENSE.
+
+#pragma once
+
+#include <cerlib/StringView.hpp>
+#include <cerlib/details/ObjectMacros.hpp>
+
+namespace cer
+{
+namespace details
+{
+class LuaScriptImpl;
+}
+
+struct LuaCode
+{
+    constexpr explicit LuaCode(StringView code)
+        : code(code)
+    {
+    }
+
+    StringView code;
+};
+
+class LuaScript final
+{
+    CERLIB_DECLARE_OBJECT(LuaScript);
+
+  public:
+    explicit LuaScript(StringView asset_name);
+
+    explicit LuaScript(StringView name, LuaCode code);
+
+    auto name() const -> StringView;
+
+    auto code() const -> StringView;
+};
+} // namespace cer
+
+constexpr auto operator""_lua(const char* code, size_t length) -> cer::LuaCode
+{
+    return cer::LuaCode{cer::StringView{code, length}};
+}

include/cerlib/LuaState.hpp

@@ -0,0 +1,63 @@
+// Copyright (C) 2023-2024 Cemalettin Dervis
+// This file is part of cerlib.
+// For conditions of distribution and use, see copyright notice in LICENSE.
+
+#pragma once
+
+#include <cerlib/Game.hpp>
+#include <cerlib/List.hpp>
+#include <cerlib/LuaScript.hpp>
+#include <cerlib/Window.hpp>
+#include <cerlib/details/ObjectMacros.hpp>
+#include <optional>
+#include <string>
+#include <variant>
+
+namespace cer
+{
+class LuaScript;
+
+namespace details
+{
+class LuaStateImpl;
+}
+
+enum class LuaLibraries
+{
+    All,
+};
+
+using LuaValue = std::variant<double, bool, std::string, GameTime, Window>;
+
+class LuaState final
+{
+    CERLIB_DECLARE_OBJECT(LuaState);
+
+  public:
+    explicit LuaState(LuaLibraries libraries_to_include, const List<LuaScript>& scripts = {});
+
+    auto variable(std::string_view name) const -> std::optional<LuaValue>;
+
+    template <typename T>
+    auto variable_as(std::string_view name) const -> std::optional<T>;
+
+    void set_variable(std::string_view name, const std::optional<LuaValue>& value);
+
+    void run_code(std::string_view code);
+
+    void run_script(const LuaScript& script);
+};
+
+template <typename T>
+auto LuaState::variable_as(std::string_view name) const -> std::optional<T>
+{
+    auto val = variable(name);
+
+    if (!val.has_value())
+    {
+        return std::nullopt;
+    }
+
+    return std::make_optional(std::get<T>(std::move(*val)));
+}
+} // namespace cer

src/CMakeLists.txt

@@ -63,6 +63,8 @@ set(cerlib_public_files
   cerlib/Defer.hpp
   cerlib/Tuple.hpp
   cerlib/Camera.hpp
+  cerlib/LuaState.hpp
+  cerlib/LuaScript.hpp
   cerlib.hpp
 )
 
@@ -106,6 +108,7 @@ target_precompile_headers(cerlib PRIVATE
   <utility>
   <variant>
   <vector>
+  <cerlib/lua/sol.hpp>
   <cerlib/Span.hpp>
   <cerlib/Array.hpp>
   <cerlib/String.hpp>
@@ -129,9 +132,39 @@ target_precompile_headers(cerlib PRIVATE
   <cerlib/util/narrow_cast.hpp>
 )
 
-set_source_files_properties(
-  cerlib/graphics/stb_image.cpp
-  PROPERTIES
+set_property(SOURCE
+  lua/ldebug.cpp
+  graphics/stb_image.cpp
+  lua/lapi.cpp
+  lua/lauxlib.cpp
+  lua/lcode.cpp
+  lua/lcorolib.cpp
+  lua/ldblib.cpp
+  lua/lctype.cpp
+  lua/ldump.cpp
+  lua/ldo.cpp
+  lua/lfunc.cpp
+  lua/linit.cpp
+  lua/lgc.cpp
+  lua/liolib.cpp
+  lua/llex.cpp
+  lua/lmathlib.cpp
+  lua/lmem.cpp
+  lua/loadlib.cpp
+  lua/lobject.cpp
+  lua/lopcodes.cpp
+  lua/loslib.cpp
+  lua/lparser.cpp
+  lua/lstate.cpp
+  lua/lstring.cpp
+  lua/ltable.cpp
+  lua/ltablib.cpp
+  lua/ltm.cpp
+  lua/lundump.cpp
+  lua/lvm.cpp
+  lua/lutf8lib.cpp
+  lua/lzio.cpp
+  PROPERTY
     SKIP_PRECOMPILE_HEADERS ON
 )
 
@@ -147,6 +180,7 @@ set(src_sub_dirs
   game
   graphics
   input
+  lua
   math
   shadercompiler
   util

src/cerlib/contentmanagement/ContentManager.cpp

@@ -198,6 +198,16 @@ auto ContentManager::load_sound(StringView name) -> Sound
     });
 }
 
+auto ContentManager::load_lua_script(StringView name) -> LuaScript
+{
+    const auto key = String{name};
+
+    return lazy_load<LuaScript, LuaScriptImpl>(key.view(), name, [](StringView full_name) {
+        const auto data = filesystem::load_asset_data(full_name);
+        return LuaScript{full_name, LuaCode{data.as_string_view()}};
+    });
+}
+
 auto ContentManager::load_custom_asset(StringView      type_id,
                                        StringView      name,
                                        const std::any& extra_info) -> SharedPtr<Asset>

src/cerlib/contentmanagement/ContentManager.hpp

@@ -8,11 +8,13 @@
 #include <cerlib/CopyMoveMacros.hpp>
 #include <cerlib/Error.hpp>
 #include <cerlib/Logging.hpp>
+#include <cerlib/LuaScript.hpp>
 #include <cerlib/Shader.hpp>
 #include <cerlib/Span.hpp>
 #include <cerlib/String.hpp>
 #include <cerlib/Variant.hpp>
 #include <cerlib/graphics/ShaderImpl.hpp>
+#include <cerlib/lua/LuaScriptImpl.hpp>
 #include <cerlib/util/StringUnorderedMap.hpp>
 
 namespace cer::details
@@ -43,6 +45,8 @@ class ContentManager final
 
     auto load_sound(StringView name) -> Sound;
 
+    auto load_lua_script(StringView name) -> LuaScript;
+
     auto load_custom_asset(StringView type_id, StringView name, const std::any& extra_info)
         -> SharedPtr<Asset>;
 
@@ -62,7 +66,7 @@ class ContentManager final
     // vanished), they notify the content manager. The content manager then removes those
     // assets from its list.
     using ReferenceToLoadedAsset =
-        Variant<ImageImpl*, SoundImpl*, ShaderImpl*, FontImpl*, CustomAsset>;
+        std::variant<ImageImpl*, SoundImpl*, ShaderImpl*, FontImpl*, LuaScriptImpl*, CustomAsset>;
 
     using MapOfLoadedAssets = StringUnorderedMap<ReferenceToLoadedAsset>;
 

src/cerlib/lua/Files.cmake

@@ -0,0 +1,64 @@
+set(lua_files
+  lapi.cpp
+  lapi.h
+  lauxlib.cpp
+  lauxlib.h
+  lbaselib.cpp
+  lcode.cpp
+  lcode.h
+  lcorolib.cpp
+  lctype.cpp
+  ldblib.cpp
+  ldebug.cpp
+  ldebug.h
+  ldo.cpp
+  ldo.h
+  ldump.cpp
+  lfunc.cpp
+  lfunc.h
+  lgc.cpp
+  lgc.h
+  linit.cpp
+  liolib.cpp
+  ljumptab.h
+  llex.cpp
+  llex.h
+  llimits.h
+  lmathlib.cpp
+  lmem.cpp
+  lmem.h
+  loadlib.cpp
+  lobject.cpp
+  lobject.h
+  lopcodes.cpp
+  lopcodes.h
+  lopnames.h
+  lparser.cpp
+  lparser.h
+  lprefix.h
+  lstate.cpp
+  lstring.cpp
+  lstring.h
+  lstrlib.cpp
+  ltable.cpp
+  ltable.h
+  ltablib.cpp
+  ltm.cpp
+  ltm.h
+  lua.h
+  luaconf.h
+  lualib.h
+  lundump.cpp
+  lundump.h
+  lutf8lib.cpp
+  lvm.cpp
+  lvm.h
+  lzio.cpp
+  lzio.h
+  LuaState.cpp
+  LuaStateImpl.hpp
+  LuaStateImpl.cpp
+  LuaScript.cpp
+  LuaScriptImpl.hpp
+  LuaScriptImpl.cpp
+)