Initialise script engine off main thread (#22230)

* Initialise script engine off main thread

* Do not run ScriptEngine.Tick() during initialisation/preloading

* Add 'Loading plugin engine…' string

* Add changelog entry

---------

Co-authored-by: Bas <Basssiiie@users.noreply.github.com>

data/language/en-GB.txt

@@ -3719,6 +3719,7 @@ STR_6644    :Touch enhancements
 STR_6645    :Makes some UI elements bigger so they are easier to click or tap.
 STR_6646    :Author: {STRING}
 STR_6647    :Authors: {STRING}
+STR_6648    :Loading plugin engine…
 
 #############
 # Scenarios #

distribution/changelog.txt

@@ -4,6 +4,7 @@
 - Feature: [#20832] The ride music tab now shows a track listing for the current music style.
 - Feature: [#22172] [Plugin] Expose ride satisfaction ratings to the plugin API.
 - Feature: [#22213] [Plugin] Allow plugins to focus on textboxes in custom windows.
+- Change: [#22230] The plugin/script engine is now initialised off the main thread.
 - Change: [#22251] Hide author info in the scenery window unless debug tools are active.
 
 0.4.12 (2024-07-07)

src/openrct2-ui/UiContext.cpp

@@ -131,7 +131,7 @@ public:
         SDL_QuitSubSystem(SDL_INIT_VIDEO);
     }
 
-    void Initialise() override
+    void InitialiseScriptExtensions() override
     {
 #ifdef ENABLE_SCRIPTING
         auto& scriptEngine = GetContext()->GetScriptEngine();

src/openrct2/Context.cpp

@@ -523,18 +523,14 @@ namespace OpenRCT2
 
                 // TODO: preload the title scene in another (parallel) job.
                 preloaderScene->AddJob([this]() { InitialiseRepositories(); });
+                preloaderScene->AddJob([this]() { InitialiseScriptEngine(); });
             }
             else
             {
                 InitialiseRepositories();
+                InitialiseScriptEngine();
             }
 
-#ifdef ENABLE_SCRIPTING
-            _scriptEngine.Initialise();
-#endif
-
-            _uiContext->Initialise();
-
             return true;
         }
 
@@ -574,6 +570,17 @@ namespace OpenRCT2
             OpenProgress(STR_LOADING_GENERIC);
         }
 
+        void InitialiseScriptEngine()
+        {
+#ifdef ENABLE_SCRIPTING
+            OpenProgress(STR_LOADING_PLUGIN_ENGINE);
+            _scriptEngine.Initialise();
+            _uiContext->InitialiseScriptExtensions();
+
+            OpenProgress(STR_LOADING_GENERIC);
+#endif
+        }
+
     public:
         void InitialiseDrawingEngine() final override
         {
@@ -1349,7 +1356,10 @@ namespace OpenRCT2
 
             ChatUpdate();
 #ifdef ENABLE_SCRIPTING
+            if (GetActiveScene() != GetPreloaderScene())
+            {
                 _scriptEngine.Tick();
+            }
 #endif
             _stdInOutConsole.ProcessEvalQueue();
             _uiContext->Tick();

src/openrct2/localisation/StringIds.h

@@ -1692,6 +1692,8 @@ enum : StringId
     STR_STRING_M_OF_N = 6642,
     STR_STRING_M_OF_N_KIB = 6643,
 
+    STR_LOADING_PLUGIN_ENGINE = 6648,
+
     // Have to include resource strings (from scenarios and objects) for the time being now that language is partially working
     /* MAX_STR_COUNT = 32768 */ // MAX_STR_COUNT - upper limit for number of strings, not the current count strings
 };

src/openrct2/scripting/ScriptEngine.cpp

@@ -913,6 +913,11 @@ bool ScriptEngine::ShouldStartPlugin(const std::shared_ptr<Plugin>& plugin)
 
 void ScriptEngine::Tick()
 {
+    if (!_initialised)
+    {
+        return;
+    }
+
     PROFILED_FUNCTION();
 
     CheckAndStartPlugins();

src/openrct2/ui/DummyUiContext.cpp

@@ -24,7 +24,7 @@ namespace OpenRCT2::Ui
         std::unique_ptr<IWindowManager> const _windowManager = CreateDummyWindowManager();
 
     public:
-        void Initialise() override
+        void InitialiseScriptExtensions() override
         {
         }
         void Tick() override

src/openrct2/ui/UiContext.h

@@ -99,7 +99,7 @@ namespace OpenRCT2
         {
             virtual ~IUiContext() = default;
 
-            virtual void Initialise() abstract;
+            virtual void InitialiseScriptExtensions() abstract;
             virtual void Tick() abstract;
             virtual void Draw(DrawPixelInfo& dpi) abstract;