From 70eacbbefc666b6366628206028a0b5e9fcd1183 Mon Sep 17 00:00:00 2001
From: uramer <antonuramer@gmail.com>
Date: Fri, 20 May 2022 19:27:21 +0000
Subject: [PATCH] onObjectActive and onItemActive Lua engine handlers

---
 apps/openmw/mwlua/globalscripts.hpp           | 12 +++++++++-
 apps/openmw/mwlua/luamanagerimp.cpp           | 22 +++++++++++++------
 apps/openmw/mwlua/luamanagerimp.hpp           |  2 +-
 apps/openmw/mwlua/worldview.hpp               |  3 +++
 .../lua-scripting/engine_handlers.rst         |  5 +++++
 5 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/apps/openmw/mwlua/globalscripts.hpp b/apps/openmw/mwlua/globalscripts.hpp
index 2737dabaca..2b40aabd9d 100644
--- a/apps/openmw/mwlua/globalscripts.hpp
+++ b/apps/openmw/mwlua/globalscripts.hpp
@@ -19,15 +19,25 @@ namespace MWLua
         GlobalScripts(LuaUtil::LuaState* lua) :
             LuaUtil::ScriptsContainer(lua, "Global", ESM::LuaScriptCfg::sGlobal)
         {
-            registerEngineHandlers({&mActorActiveHandlers, &mNewGameHandlers, &mPlayerAddedHandlers});
+            registerEngineHandlers({
+                &mObjectActiveHandlers,
+                &mActorActiveHandlers,
+                &mItemActiveHandlers,
+                &mNewGameHandlers,
+                &mPlayerAddedHandlers
+            });
         }
 
         void newGameStarted() { callEngineHandlers(mNewGameHandlers); }
+        void objectActive(const GObject& obj) { callEngineHandlers(mObjectActiveHandlers, obj); }
         void actorActive(const GObject& obj) { callEngineHandlers(mActorActiveHandlers, obj); }
+        void itemActive(const GObject& obj) { callEngineHandlers(mItemActiveHandlers, obj); }
         void playerAdded(const GObject& obj) { callEngineHandlers(mPlayerAddedHandlers, obj); }
 
     private:
+        EngineHandlerList mObjectActiveHandlers{"onObjectActive"};
         EngineHandlerList mActorActiveHandlers{"onActorActive"};
+        EngineHandlerList mItemActiveHandlers{"onItemActive"};
         EngineHandlerList mNewGameHandlers{"onNewGame"};
         EngineHandlerList mPlayerAddedHandlers{"onPlayerAdded"};
     };
diff --git a/apps/openmw/mwlua/luamanagerimp.cpp b/apps/openmw/mwlua/luamanagerimp.cpp
index 5cfc52d737..6894208c07 100644
--- a/apps/openmw/mwlua/luamanagerimp.cpp
+++ b/apps/openmw/mwlua/luamanagerimp.cpp
@@ -209,15 +209,23 @@ namespace MWLua
             mGlobalScripts.newGameStarted();
         }
 
-        for (ObjectId id : mActorAddedEvents)
+        for (ObjectId id : mObjectAddedEvents)
         {
             GObject obj(id, objectRegistry);
             if (obj.isValid())
-                mGlobalScripts.actorActive(obj);
+            {
+                mGlobalScripts.objectActive(obj);
+                const MWWorld::Class& objClass = obj.ptr().getClass();
+                if (objClass.isActor())
+                    mGlobalScripts.actorActive(obj);
+                if (mWorldView.isItem(obj.ptr()))
+                    mGlobalScripts.itemActive(obj);
+            }
             else if (luaDebug)
-                Log(Debug::Verbose) << "Can not call onActorActive engine handler: object" << idToString(id) << " is already removed";
+                Log(Debug::Verbose) << "Could not resolve a Lua object added event: object" << idToString(id)
+                    << " is already removed";
         }
-        mActorAddedEvents.clear();
+        mObjectAddedEvents.clear();
 
         if (!mWorldView.isPaused())
             mGlobalScripts.update(frameDuration);
@@ -267,7 +275,7 @@ namespace MWLua
         mLocalEvents.clear();
         mGlobalEvents.clear();
         mInputEvents.clear();
-        mActorAddedEvents.clear();
+        mObjectAddedEvents.clear();
         mLocalEngineEvents.clear();
         mNewGameStarted = false;
         mPlayerChanged = false;
@@ -338,8 +346,8 @@ namespace MWLua
             mLocalEngineEvents.push_back({getId(ptr), LocalScripts::OnActive{}});
         }
 
-        if (ptr.getClass().isActor() && ptr != mPlayer)
-            mActorAddedEvents.push_back(getId(ptr));
+        if (ptr != mPlayer)
+            mObjectAddedEvents.push_back(getId(ptr));
     }
 
     void LuaManager::objectRemovedFromScene(const MWWorld::Ptr& ptr)
diff --git a/apps/openmw/mwlua/luamanagerimp.hpp b/apps/openmw/mwlua/luamanagerimp.hpp
index 0c08deb4fb..871ab0af26 100644
--- a/apps/openmw/mwlua/luamanagerimp.hpp
+++ b/apps/openmw/mwlua/luamanagerimp.hpp
@@ -162,7 +162,7 @@ namespace MWLua
         std::unique_ptr<LuaUtil::UserdataSerializer> mLocalLoader;
 
         std::vector<MWBase::LuaManager::InputEvent> mInputEvents;
-        std::vector<ObjectId> mActorAddedEvents;
+        std::vector<ObjectId> mObjectAddedEvents;
 
         struct CallbackWithData
         {
diff --git a/apps/openmw/mwlua/worldview.hpp b/apps/openmw/mwlua/worldview.hpp
index 004fcfc0c3..accf2758f0 100644
--- a/apps/openmw/mwlua/worldview.hpp
+++ b/apps/openmw/mwlua/worldview.hpp
@@ -62,6 +62,9 @@ namespace MWLua
         void load(ESM::ESMReader& esm);
         void save(ESM::ESMWriter& esm) const;
 
+        // TODO: move this functionality to MWClass
+        bool isItem(const MWWorld::Ptr& ptr) { return chooseGroup(ptr) == &mItemsInScene; }
+
     private:
         struct ObjectGroup
         {
diff --git a/docs/source/reference/lua-scripting/engine_handlers.rst b/docs/source/reference/lua-scripting/engine_handlers.rst
index 524314341c..ca05c9b8e1 100644
--- a/docs/source/reference/lua-scripting/engine_handlers.rst
+++ b/docs/source/reference/lua-scripting/engine_handlers.rst
@@ -40,8 +40,13 @@ Engine handler is a function defined by a script, that can be called by the engi
     - New game is started
   * - onPlayerAdded(player)
     - Player added to the game world. The argument is a `Game object`.
+  * - onObjectActive(object)
+    - Object becomes active.
   * - onActorActive(actor)
     - Actor (NPC or Creature) becomes active.
+  * - onItemActive(item)
+    - | Item (Weapon, Potion, ...) becomes active in a cell.
+      | Does not apply to items in inventories or containers.
 
 **Only for local scripts**