Fry3DX 0.4: an easy 3D modeller

Shapes with live settings, shape editing, knife and hole tools, drawing
shapes onto other objects, combining objects (add / subtract / overlap),
copies, thickness, painting with stickers and layers, a Layout tab, a
Print tab with checks, packed .fry files with autosave, export to GLB,
glTF, FBX, OBJ, 3MF, STL and PLY, folders in Layers, its own crash
screen, and a website for GitHub Pages in docs/.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NMSrd5oe1GpUD7E6d825KP

engine/engine.h

@@ -0,0 +1,62 @@
+#pragma once
+#include <utility>
+#include <string>
+#include <vector>
+
+namespace keel {
+// Where this game keeps its config and saves (SDL_GetPrefPath), "" before it starts.
+const std::string& prefPath();
+
+
+class Renderer;
+
+// What a game plugs into the engine. Like Source, the game owns its server and
+// client code; the engine owns the window, renderer, console and main loop.
+class Game {
+public:
+    virtual ~Game() = default;
+    virtual const char* name() const = 0;  // folder for config/saves, e.g. "fry3dx"
+    virtual const char* title() const = 0; // window title
+
+    virtual void init() {}
+    virtual void shutdown() {}
+    // Every frame, before rendering. dt in seconds.
+    virtual void frame(double dt) = 0;
+    // Queue draws and UI. Not called on a dedicated server.
+    virtual void render(Renderer&) {}
+    // True while the game shows a menu: the mouse is released and binds don't run.
+    virtual bool wantsCursor() const { return false; }
+    // Dear ImGui docking (windows that dock into each other and the screen): tools like this one.
+    virtual bool dockingUi() const { return false; }
+    // Escape was pressed (the console has its own key).
+    virtual void onEscape() {}
+    // The window's close button (or the OS asking it to close): false keeps it open (to ask
+    // about saving first; the game quits later itself). The quit command always quits.
+    virtual bool allowQuit() { return true; }
+    // Hot reload: called twice a second (hotreload 1) after the engine reloaded what changed
+    // (`changed`: textures, models, sounds); the game reloads its own (scripts, the map).
+    virtual void hotReload(const std::vector<std::string>& changed) { (void)changed; }
+};
+
+// Runs until quit. Command line works like Quake/Source:
+//   fry3dx file.fry +set r_vsync 0
+int run(Game& game, int argc, char** argv);
+
+bool isDedicated();
+// Started with -test (automated runs: no input, no audio, no splash).
+bool isTestMode();
+// Fullscreen resolutions of the window's display, largest first (empty when dedicated).
+std::vector<std::pair<int, int>> displayResolutions();
+// The graphics API in use ("Vulkan 1.3", "OpenGL 4.6").
+const char* rendererName();
+// This build: its git commit and date ("1a2b3c4, 2026-10-11 02:14").
+const char* buildVersion();
+// The game's mods folder (<exe dir>/mods/<game>/).
+const std::string& modsDirectory();
+// Takes the mods down and mounts the ones fs_mods names now (scripts and new files apply from
+// the next map; textures/models already loaded keep their old look until a restart).
+void applyMods();
+// Starts the game again with the same command line (after the config is saved).
+void restart();
+
+} // namespace keel