add lua debug mode

scripts/cube_logic.lua

@@ -36,6 +36,8 @@ local pyramid_indices = {
 }
 
 local math3d = require("math3d")
+local string_format = string.format
+local table_concat = table.concat
 
 local InputState = {}
 InputState.__index = InputState
@@ -79,6 +81,13 @@ end
 
 gui_input = InputState:new()
 
+local function log_debug(fmt, ...)
+    if not lua_debug or not fmt then
+        return
+    end
+    print(string_format(fmt, ...))
+end
+
 local rotation_speeds = {x = 0.5, y = 0.7}
 
 local shader_variants = {
@@ -140,6 +149,7 @@ local function update_camera_zoom(delta)
     camera.eye[1] = camera.center[1] + normalizedX * targetDistance
     camera.eye[2] = camera.center[2] + normalizedY * targetDistance
     camera.eye[3] = camera.center[3] + normalizedZ * targetDistance
+    log_debug("zoom delta=%.2f -> distance=%.2f", delta, targetDistance)
 end
 
 local function build_model(time)
@@ -179,22 +189,26 @@ local function create_pyramid(position, shader_key)
 end
 
 function get_scene_objects()
-    return {
+    local objects = {
         create_cube({0.0, 0.0, 0.0}, 1.0, "cube"),
         create_cube({3.0, 0.0, 0.0}, 0.8, "cube"),
         create_cube({-3.0, 0.0, 0.0}, 1.2, "cube"),
         create_pyramid({0.0, -0.5, -4.0}, "pyramid"),
     }
+    if lua_debug then
+        local labels = {}
+        for idx, obj in ipairs(objects) do
+            table.insert(labels, string_format("[%d:%s]", idx, obj.shader_key))
+        end
+        log_debug("get_scene_objects -> %d entries: %s", #objects, table_concat(labels, ", "))
+    end
+    return objects
 end
 
 function get_shader_paths()
     return shader_variants
 end
 
-function get_gui_commands()
-    return {}
-end
-
 function get_view_projection(aspect)
     if gui_input then
         update_camera_zoom(gui_input.wheel)

src/app/sdl3_app.hpp

@@ -52,7 +52,7 @@ struct SwapChainSupportDetails {
 
 class Sdl3App {
 public:
-    explicit Sdl3App(const std::filesystem::path& scriptPath);
+    explicit Sdl3App(const std::filesystem::path& scriptPath, bool luaDebug = false);
     void Run();
 
 private:

src/app/sdl3_app_core.cpp

@@ -81,7 +81,8 @@ void ThrowSdlErrorIfFailed(bool success, const char* context) {
 
 } // namespace
 
-Sdl3App::Sdl3App(const std::filesystem::path& scriptPath) : cubeScript_(scriptPath) {
+Sdl3App::Sdl3App(const std::filesystem::path& scriptPath, bool luaDebug)
+    : cubeScript_(scriptPath, luaDebug) {
     TRACE_FUNCTION();
     TRACE_VAR(scriptPath);
 }
@@ -140,25 +141,22 @@ void Sdl3App::MainLoop() {
                 running = false;
             } else if (event.type == SDL_EVENT_WINDOW_PIXEL_SIZE_CHANGED) {
                 framebufferResized_ = true;
-            } else if (guiHasCommands_) {
-                ProcessGuiEvent(event);
             }
+            ProcessGuiEvent(event);
         }
 
-        if (guiHasCommands_) {
-            float mouseX = 0.0f;
-            float mouseY = 0.0f;
-            SDL_GetMouseState(&mouseX, &mouseY);
-            guiInputSnapshot_.mouseX = mouseX;
-            guiInputSnapshot_.mouseY = mouseY;
-            cubeScript_.UpdateGuiInput(guiInputSnapshot_);
-            if (guiRenderer_) {
-                guiCommands_ = cubeScript_.LoadGuiCommands();
-                guiRenderer_->Prepare(guiCommands_, swapChainExtent_.width, swapChainExtent_.height);
-            }
-            guiInputSnapshot_.wheel = 0.0f;
-            guiInputSnapshot_.textInput.clear();
+        float mouseX = 0.0f;
+        float mouseY = 0.0f;
+        SDL_GetMouseState(&mouseX, &mouseY);
+        guiInputSnapshot_.mouseX = mouseX;
+        guiInputSnapshot_.mouseY = mouseY;
+        cubeScript_.UpdateGuiInput(guiInputSnapshot_);
+        if (guiHasCommands_ && guiRenderer_) {
+            guiCommands_ = cubeScript_.LoadGuiCommands();
+            guiRenderer_->Prepare(guiCommands_, swapChainExtent_.width, swapChainExtent_.height);
         }
+        guiInputSnapshot_.wheel = 0.0f;
+        guiInputSnapshot_.textInput.clear();
 
         auto now = std::chrono::steady_clock::now();
         float time = std::chrono::duration<float>(now - start).count();

src/main.cpp

@@ -42,6 +42,7 @@ struct RuntimeConfig {
     uint32_t width = sdl3cpp::app::kWidth;
     uint32_t height = sdl3cpp::app::kHeight;
     std::filesystem::path scriptPath;
+    bool luaDebug = false;
 };
 
 RuntimeConfig GenerateDefaultRuntimeConfig(const char* argv0) {
@@ -126,6 +127,13 @@ RuntimeConfig LoadRuntimeConfigFromJson(const std::filesystem::path& configPath,
 
     config.width = parseDimension("window_width", config.width);
     config.height = parseDimension("window_height", config.height);
+    if (document.HasMember("lua_debug")) {
+        const auto& value = document["lua_debug"];
+        if (!value.IsBool()) {
+            throw std::runtime_error("JSON member 'lua_debug' must be a boolean");
+        }
+        config.luaDebug = value.GetBool();
+    }
 
     return config;
 }
@@ -300,7 +308,7 @@ int main(int argc, char** argv) {
                 throw std::runtime_error("Unable to determine platform config directory");
             }
         }
-        sdl3cpp::app::Sdl3App app(options.runtimeConfig.scriptPath);
+        sdl3cpp::app::Sdl3App app(options.runtimeConfig.scriptPath, options.runtimeConfig.luaDebug);
         app.Run();
     } catch (const std::exception& e) {
         std::cerr << "ERROR: " << e.what() << '\n';

src/script/cube_script.cpp

@@ -18,12 +18,14 @@ std::array<float, 16> IdentityMatrix() {
 
 } // namespace
 
-CubeScript::CubeScript(const std::filesystem::path& scriptPath)
-    : L_(luaL_newstate()), scriptDirectory_(scriptPath.parent_path()) {
+CubeScript::CubeScript(const std::filesystem::path& scriptPath, bool debugEnabled)
+    : L_(luaL_newstate()), scriptDirectory_(scriptPath.parent_path()), debugEnabled_(debugEnabled) {
     if (!L_) {
         throw std::runtime_error("Failed to create Lua state");
     }
     luaL_openlibs(L_);
+    lua_pushboolean(L_, debugEnabled_);
+    lua_setglobal(L_, "lua_debug");
     auto scriptDir = scriptPath.parent_path();
     if (!scriptDir.empty()) {
         lua_getglobal(L_, "package");

src/script/cube_script.hpp

@@ -68,7 +68,7 @@ public:
     using GuiColor = ::sdl3cpp::script::GuiColor;
 
 public:
-    explicit CubeScript(const std::filesystem::path& scriptPath);
+    explicit CubeScript(const std::filesystem::path& scriptPath, bool debugEnabled = false);
     ~CubeScript();
 
     struct ShaderPaths {
@@ -107,6 +107,7 @@ private:
     int guiInputRef_ = LUA_REFNIL;
     int guiCommandsFnRef_ = LUA_REFNIL;
     std::filesystem::path scriptDirectory_;
+    bool debugEnabled_ = false;
 };
 
 } // namespace sdl3cpp::script