🎮 New mod type: '.gadget'

Gadgets are essentially scripts wrapped as modcache entries. The name "gadgets" is inspired by Beyond All Reason RTS (running open source Recoil engine). Usual modcache treatment applies:
* can be zipped or unzipped in directory
* can have preview (aka 'mini') image
* selectable via MainSelectorUI (open from TopMenubarUI, menu Tools, button BrowseGadgets

All methods of loading a script were extended to recognize the .gadget suffix and load the gadget appropriately:
* the 'loadscript' console command
* the cvars 'app_custom_scripts' and 'app_recent_scripts'
* the -runscript command line argument
NOTE that although `ScriptCategory::GADGET` was added, all the above methods still load everything as `ScriptCategory::CUSTOM` and the game adjusts it based on extension.

The ScriptMonitorUI was extended to display .gadget file name for `ScriptCategory::GADGET` script units.

Example .gadget file:
```
; This is a .gadget mod - basically a script wrapped as a modcache entry.
; The .gadget file must be present (even if empty) to get recognized.
; The script must have same base filename, i.e. 'foo.gadget' -> 'foo.as'
; Any extra include scripts or other resources can be bundled.
; -----------------------------------------------------------------------

; Name to display in Selector UI.
gadget_name "Engine Tool"

; Authors (Syntax: <credit>, <forumID>, <name>, [<email>]) - multiple authors can be given.
gadget_author "base script" 351 ohlidalp

; Description to display in Selector UI.
gadget_description "In-game engine diag and adjustment."

; Category for Selector UI (300 = Generic gadgets, 301 = Actor gadgets, 302 = Terrain gadgets).
gadget_category 301
```

source/main/Application.h

@@ -321,6 +321,26 @@ enum LoaderType //!< Search mode for `ModCache::Query()` & Operation mode for `G
     LT_AddonPart, // No script alias, invoked manually, ext: addonpart
     LT_Tuneup,    // No script alias, invoked manually, ext: tuneup
     LT_AssetPack, // No script alias, invoked manually, ext: assetpack
+    LT_Gadget,    // No script alias, invoked manually, ext: gadget
+};
+
+enum CacheCategoryId
+{
+    CID_None = 0,
+
+    CID_GadgetsGeneric = 300,
+    CID_GadgetsActor = 301,
+    CID_GadgetsTerrain = 302,
+
+    CID_Projects = 8000, //!< For truck files under 'projects/' directory, to allow listing from editors.
+    CID_Tuneups = 8001, //!< For unsorted tuneup files.
+
+    CID_Max = 9000, //!< SPECIAL VALUE - Maximum allowed to be present in any mod files.
+    CID_Unsorted = 9990,
+    CID_All = 9991,
+    CID_Fresh = 9992,
+    CID_Hidden = 9993,
+    CID_SearchResults = 9994,
 };
 
 enum class TObjSpecialObject

source/main/gui/panels/GUI_MainSelector.cpp

@@ -31,6 +31,7 @@
 #include "GUI_LoadingWindow.h"
 #include "InputEngine.h"
 #include "Language.h"
+#include "ScriptEngine.h"
 #include "Utils.h"
 
 #include <MyGUI.h>
@@ -622,7 +623,15 @@ void MainSelector::Apply()
     ROR_ASSERT(m_selected_entry > -1); // Programmer error
     DisplayEntry& sd_entry = m_display_entries[m_selected_entry];
 
-    if (m_loader_type == LT_Terrain &&
+    if (m_loader_type == LT_Gadget)
+    {
+        auto request = new LoadScriptRequest();
+        request->lsr_filename = sd_entry.sde_entry->fname;
+        request->lsr_category = ScriptCategory::GADGET;
+        App::GetGameContext()->PushMessage(Message(MSG_APP_LOAD_SCRIPT_REQUESTED, request));
+        this->Close();
+    }
+    else if (m_loader_type == LT_Terrain &&
         App::app_state->getEnum<AppState>() == AppState::MAIN_MENU)
     {
         App::GetGameContext()->PushMessage(Message(MSG_SIM_LOAD_TERRN_REQUESTED, sd_entry.sde_entry->fname));

source/main/gui/panels/GUI_ScriptMonitor.cpp

@@ -58,7 +58,14 @@ void ScriptMonitor::Draw()
         ImGui::TextDisabled("%d", id);
         ImGui::NextColumn();
         ImGui::AlignTextToFramePadding();
-        ImGui::Text("%s", unit.scriptName.c_str());
+        if (unit.scriptCategory == ScriptCategory::GADGET && unit.originatingGadget)
+        {
+            ImGui::Text("%s", unit.originatingGadget->fname.c_str());
+        }
+        else
+        {
+            ImGui::Text("%s", unit.scriptName.c_str());
+        }
         ImGui::NextColumn();
         switch (unit.scriptCategory)
         {
@@ -71,13 +78,20 @@ void ScriptMonitor::Draw()
             break;
 
         case ScriptCategory::CUSTOM:
+        case ScriptCategory::GADGET:
         {
+            std::string filename = unit.scriptName;
+            if (unit.scriptCategory == ScriptCategory::GADGET && unit.originatingGadget)
+            {
+                filename = unit.originatingGadget->fname;
+            }
+
             if (ImGui::Button(_LC("ScriptMonitor", "Reload")))
             {
                 App::GetGameContext()->PushMessage(Message(MSG_APP_UNLOAD_SCRIPT_REQUESTED, new ScriptUnitID_t(id)));
                 LoadScriptRequest* req = new LoadScriptRequest();
                 req->lsr_category = unit.scriptCategory;
-                req->lsr_filename = unit.scriptName;
+                req->lsr_filename = filename;
                 App::GetGameContext()->ChainMessage(Message(MSG_APP_LOAD_SCRIPT_REQUESTED, req));
             }
             ImGui::SameLine();
@@ -87,13 +101,13 @@ void ScriptMonitor::Draw()
             }
 
             ImGui::SameLine();
-            bool autoload_set = std::find(autoload.begin(), autoload.end(), unit.scriptName) != autoload.end();
+            bool autoload_set = std::find(autoload.begin(), autoload.end(), filename) != autoload.end();
             if (ImGui::Checkbox(_LC("ScriptMonitor", "Autoload"), &autoload_set))
             {
                 if (autoload_set)
-                    CvarAddFileToList(App::app_custom_scripts, unit.scriptName);
+                    CvarAddFileToList(App::app_custom_scripts, filename);
                 else
-                    CvarRemoveFileFromList(App::app_custom_scripts, unit.scriptName);
+                    CvarRemoveFileFromList(App::app_custom_scripts, filename);
             }
             break;
         }

source/main/gui/panels/GUI_TopMenubar.cpp

@@ -737,6 +737,12 @@ void TopMenubar::Draw(float dt)
                 }
             }
 
+            if (ImGui::Button(_LC("TopMenubar", "Browse gadgets ...")))
+            {
+                App::GetGameContext()->PushMessage(Message(MSG_GUI_OPEN_SELECTOR_REQUESTED, new LoaderType(LT_Gadget)));
+                m_open_menu = TopMenu::TOPMENU_NONE;
+            }
+
             ImGui::Separator();
             ImGui::TextColored(GRAY_HINT_TEXT, "%s", _LC("TopMenubar", "Pre-spawn diag. options:"));
 

source/main/resources/CacheSystem.cpp

@@ -139,6 +139,7 @@ CacheSystem::CacheSystem()
     m_known_extensions.push_back("addonpart");
     m_known_extensions.push_back("tuneup");
     m_known_extensions.push_back("assetpack");
+    m_known_extensions.push_back("gadget");
 
     // register the dirs
     m_content_dirs.push_back("mods");
@@ -793,6 +794,12 @@ void CacheSystem::AddFile(String group, Ogre::FileInfo f, String ext)
             FillAssetPackDetailInfo(entry, ds);
             new_entries.push_back(entry);
         }
+        else if (ext == "gadget")
+        {
+            CacheEntryPtr entry = new CacheEntry();
+            FillGadgetDetailInfo(entry, ds);
+            new_entries.push_back(entry);
+        }
         else
         {
             CacheEntryPtr entry = new CacheEntry();
@@ -1285,6 +1292,46 @@ void CacheSystem::FillAssetPackDetailInfo(CacheEntryPtr &entry, Ogre::DataStream
     }
 }
 
+void CacheSystem::FillGadgetDetailInfo(CacheEntryPtr& entry, Ogre::DataStreamPtr ds)
+{
+    GenericDocumentPtr doc = new GenericDocument();
+    BitMask_t options 
+        = GenericDocument::OPTION_ALLOW_SLASH_COMMENTS 
+        | GenericDocument::OPTION_ALLOW_NAKED_STRINGS
+        | GenericDocument::OPTION_NAKEDSTR_USCORES_TO_SPACES;
+    doc->loadFromDataStream(ds, options);
+
+    GenericDocContextPtr ctx = new GenericDocContext(doc);
+    while (!ctx->endOfFile())
+    {
+        if (ctx->isTokKeyword() && ctx->getTokKeyword() == "gadget_name" && ctx->isTokString(1))
+        {
+            entry->dname = ctx->getTokString(1);
+        }
+        else if (ctx->isTokKeyword() && ctx->getTokKeyword() == "gadget_description" && ctx->isTokString(1))
+        {
+            entry->description = ctx->getTokString(1);
+        }
+        else if (ctx->isTokKeyword() && ctx->getTokKeyword() == "gadget_category" && ctx->isTokInt(1))
+        {
+            entry->categoryid = ctx->getTokInt(1);
+        }
+        else if (ctx->isTokKeyword() && ctx->getTokKeyword() == "gadget_author")
+        {
+            int n = ctx->countLineArgs();
+            AuthorInfo author;
+            if (n > 1) { author.type = ctx->getTokString(1); }
+            if (n > 2) { author.id = ctx->getTokInt(2); }
+            if (n > 3) { author.name = ctx->getTokString(3); }
+            if (n > 4) { author.email = ctx->getTokString(4); }
+            entry->authors.push_back(author);
+        }
+
+        ctx->seekNextLine();
+    }
+
+}
+
 void CacheSystem::FillTuneupDetailInfo(CacheEntryPtr &entry, TuneupDefPtr& tuneup_def)
 {
     if (!tuneup_def->author_name.empty())
@@ -1483,6 +1530,16 @@ void CacheSystem::LoadResource(CacheEntryPtr& entry)
                 entry->resource_bundle_path, entry->resource_bundle_type, group, recursive, readonly);
             App::GetContentManager()->InitManagedMaterials(group);
         }
+        else if (entry->fext == "gadget")
+        {
+            // This is a .gadget bundle - use `inGlobalPool=false` to prevent resource name conflicts.
+            ResourceGroupManager::getSingleton().createResourceGroup(group, /*inGlobalPool=*/false);
+            ResourceGroupManager::getSingleton().addResourceLocation(
+                entry->resource_bundle_path, entry->resource_bundle_type, group, recursive, readonly);
+            App::GetContentManager()->InitManagedMaterials(group);
+            // Allow using builtin include scripts
+            App::GetContentManager()->AddResourcePack(ContentManager::ResourcePack::SCRIPTS, group);
+        }
         else
         {
             // A vehicle bundle - use `inGlobalPool=false` to prevent resource name conflicts.
@@ -2140,6 +2197,8 @@ size_t CacheSystem::Query(CacheQuery& query)
             add = (query.cqy_filter_type == LT_Tuneup);
         else if (entry->fext == "assetpack")
             add = (query.cqy_filter_type == LT_AssetPack);
+        else if (entry->fext == "gadget")
+            add = (query.cqy_filter_type == LT_Gadget);
         else if (entry->fext == "truck")
             add = (query.cqy_filter_type == LT_AllBeam || query.cqy_filter_type == LT_Vehicle || query.cqy_filter_type == LT_Truck);
         else if (entry->fext == "car")

source/main/resources/CacheSystem.h

@@ -144,21 +144,6 @@ class CacheEntry: public RefCountingObject<CacheEntry>
 
 typedef RefCountingObjectPtr<CacheEntry> CacheEntryPtr;
 
-enum CacheCategoryId
-{
-    CID_None          = 0,
-
-    CID_Projects      = 8000, //!< For truck files under 'projects/' directory, to allow listing from editors.
-    CID_Tuneups       = 8001, //!< For unsorted tuneup files.
-
-    CID_Max           = 9000, //!< SPECIAL VALUE - Maximum allowed to be present in any mod files.
-    CID_Unsorted      = 9990,
-    CID_All           = 9991,
-    CID_Fresh         = 9992,
-    CID_Hidden        = 9993,
-    CID_SearchResults = 9994,
-};
-
 struct CacheQueryResult
 {
     CacheQueryResult(CacheEntryPtr entry, size_t score);
@@ -370,6 +355,7 @@ class CacheSystem
     void FillAddonPartDetailInfo(CacheEntryPtr &entry, Ogre::DataStreamPtr ds);
     void FillTuneupDetailInfo(CacheEntryPtr &entry, TuneupDefPtr& tuneup_def);
     void FillAssetPackDetailInfo(CacheEntryPtr &entry, Ogre::DataStreamPtr ds);
+    void FillGadgetDetailInfo(CacheEntryPtr& entry, Ogre::DataStreamPtr ds);
     /// @}
 
     void GenerateHashFromFilenames();         //!< For quick detection of added/removed content
@@ -429,6 +415,11 @@ class CacheSystem
 
             {875, _LC("ModCategory", "Submarine")},
 
+            // gadgets
+            {CID_GadgetsGeneric, _LC("ModCategory", "Gadgets - Generic")},
+            {CID_GadgetsActor, _LC("ModCategory", "Gadgets - Actor")},
+            {CID_GadgetsTerrain, _LC("ModCategory", "Gadgets - Terrain")},
+
             // note: these categories are NOT in the repository:
             {5000, _LC("ModCategory", "Official Terrains")},
             {5001, _LC("ModCategory", "Night Terrains")},

source/main/scripting/ScriptEngine.cpp

@@ -826,7 +826,7 @@ String ScriptEngine::composeModuleName(String const& scriptName, ScriptCategory
 }
 
 ScriptUnitID_t ScriptEngine::loadScript(
-    String scriptName, ScriptCategory category/* = ScriptCategory::TERRAIN*/,
+    String scriptOrGadgetFileName, ScriptCategory category/* = ScriptCategory::TERRAIN*/,
     ActorPtr associatedActor /*= nullptr*/, std::string buffer /* =""*/)
 {
     // This function creates a new script unit, tries to set it up and removes it if setup fails.
@@ -836,12 +836,41 @@ ScriptUnitID_t ScriptEngine::loadScript(
     // be created early, and removed if setup fails.
     static ScriptUnitID_t id_counter = 0;
 
+    std::string basename, ext, scriptName;
+    Ogre::StringUtil::splitBaseFilename(scriptOrGadgetFileName, basename, ext);
+    CacheEntryPtr originatingGadget;
+    if (ext == "gadget")
+    {
+        originatingGadget = App::GetCacheSystem()->FindEntryByFilename(LT_Gadget, /* partial: */false, scriptOrGadgetFileName);
+        if (!originatingGadget)
+        {
+            App::GetConsole()->putMessage(Console::CONSOLE_MSGTYPE_INFO, Console::CONSOLE_SYSTEM_ERROR,
+                fmt::format("Could not load script '{}' - gadget not found.", scriptOrGadgetFileName));
+            return SCRIPTUNITID_INVALID;
+        }
+        App::GetCacheSystem()->LoadResource(originatingGadget);
+        scriptName = fmt::format("{}.as", basename);
+        // Ensure a .gadget file is always loaded as `GADGET`, even if requested as `CUSTOM`
+        category = ScriptCategory::GADGET;
+    }
+    else if (ext == "as")
+    {
+        scriptName = scriptOrGadgetFileName;
+    }
+    else
+    {
+        App::GetConsole()->putMessage(Console::CONSOLE_MSGTYPE_INFO, Console::CONSOLE_SYSTEM_ERROR,
+            fmt::format("Could not load script '{}' - unknown file extension.", scriptOrGadgetFileName));
+        return SCRIPTUNITID_INVALID;
+    }
+
     ScriptUnitID_t unit_id = id_counter++;
     auto itor_pair = m_script_units.insert(std::make_pair(unit_id, ScriptUnit()));
     m_script_units[unit_id].uniqueId = unit_id;
     m_script_units[unit_id].scriptName = scriptName;
     m_script_units[unit_id].scriptCategory = category;
     m_script_units[unit_id].scriptBuffer = buffer;
+    m_script_units[unit_id].originatingGadget = originatingGadget;
     if (category == ScriptCategory::TERRAIN)
     {
         m_terrain_script_unit = unit_id;
@@ -879,7 +908,7 @@ int ScriptEngine::setupScriptUnit(int unit_id)
     int result=0;
 
     String moduleName = this->composeModuleName(
-        m_script_units[unit_id].scriptName, m_script_units[unit_id].scriptCategory, m_script_units[unit_id].uniqueId);  
+        m_script_units[unit_id].scriptName, m_script_units[unit_id].scriptCategory, m_script_units[unit_id].uniqueId);
 
     // The builder is a helper class that will load the script file,
     // search for #include directives, and load any included files as

source/main/scripting/ScriptEngine.h

@@ -60,7 +60,8 @@ enum class ScriptCategory
     INVALID,
     ACTOR,   //!< Defined in truck file under 'scripts', contains global variable `BeamClass@ thisActor`.
     TERRAIN, //!< Defined in terrn2 file under '[Scripts]', receives terrain eventbox notifications.
-    CUSTOM   //!< Loaded by user via either: A) ingame console 'loadscript'; B) RoR.cfg 'app_custom_scripts'; C) commandline '-runscript'.
+    GADGET,  //!< Associated with a .gadget mod file, launched via UI or any method given below for CUSTOM scripts (use .gadget suffix - game will fix up category to `GADGET`).
+    CUSTOM   //!< Loaded by user via either: A) ingame console 'loadscript'; B) RoR.cfg 'app_custom_scripts'; C) commandline '-runscript'; If used with .gadget file, game will fix up category to `GADGET`.
 };
 
 const char* ScriptCategoryToString(ScriptCategory c);
@@ -80,7 +81,8 @@ struct ScriptUnit
     AngelScript::asIScriptFunction* eventCallbackExFunctionPtr = nullptr; //!< script function pointer to the event callback function
     AngelScript::asIScriptFunction* defaultEventCallbackFunctionPtr = nullptr; //!< script function pointer for spawner events
     ActorPtr associatedActor; //!< For ScriptCategory::ACTOR
-    Ogre::String scriptName;
+    CacheEntryPtr originatingGadget; //!< For ScriptCategory::GADGET ~ determines resource group
+    Ogre::String scriptName; //!< Name of the '.as' file exclusively.
     Ogre::String scriptHash;
     Ogre::String scriptBuffer;
 };
@@ -89,7 +91,7 @@ typedef std::map<ScriptUnitID_t, ScriptUnit> ScriptUnitMap;
 
 struct LoadScriptRequest
 {
-    std::string lsr_filename; //!< Load from resource (file). If buffer is supplied, use this as display name only.
+    std::string lsr_filename; //!< Load from resource ('.as' file or '.gadget' file); If buffer is supplied, use this as display name only.
     std::string lsr_buffer; //!< Load from memory buffer.
     ScriptCategory lsr_category = ScriptCategory::TERRAIN;
     ActorInstanceID_t lsr_associated_actor = ACTORINSTANCEID_INVALID; //!< For ScriptCategory::ACTOR
@@ -181,13 +183,13 @@ class ScriptEngine : public Ogre::LogListener
 
     /**
      * Loads a script
-     * @param scriptname filename to load; if buffer is supplied, this is only a display name.
+     * @param filename '.as' file or '.gadget' file to load; if buffer is supplied, this is only a display name.
      * @param category How to treat the script?
      * @param associatedActor Only for category ACTOR
      * @param buffer String with full script body; if empty, a file will be loaded as usual.
      * @return Unique ID of the script unit (because one script file can be loaded multiple times).
      */
-    ScriptUnitID_t loadScript(Ogre::String scriptname, ScriptCategory category = ScriptCategory::TERRAIN,
+    ScriptUnitID_t loadScript(Ogre::String filename, ScriptCategory category = ScriptCategory::TERRAIN,
         ActorPtr associatedActor = nullptr, std::string buffer = "");
 
     /**