From b4976354a522f2f0aa20254d159204dbf8cc781a Mon Sep 17 00:00:00 2001
From: elsid <elsid.mail@gmail.com>
Date: Wed, 24 Apr 2024 11:09:13 +0200
Subject: [PATCH] Use correct frame and stats for lua worker

When a loading screen appears during the frame processing, the frame number
returned by the viewer is incremented and the stats reporting goes into the
wrong frame. Pass frame number and stats object from the main thread to avoid
this.
---
 apps/openmw/engine.cpp       |  7 ++++---
 apps/openmw/mwlua/worker.cpp | 33 ++++++++++++++++-----------------
 apps/openmw/mwlua/worker.hpp | 25 +++++++++++++++++--------
 3 files changed, 37 insertions(+), 28 deletions(-)

diff --git a/apps/openmw/engine.cpp b/apps/openmw/engine.cpp
index 179dbcdc32..26d8af8304 100644
--- a/apps/openmw/engine.cpp
+++ b/apps/openmw/engine.cpp
@@ -340,11 +340,12 @@ bool OMW::Engine::frame(float frametime)
         mWorld->updateWindowManager();
     }
 
-    mLuaWorker->allowUpdate(); // if there is a separate Lua thread, it starts the update now
+    // if there is a separate Lua thread, it starts the update now
+    mLuaWorker->allowUpdate(frameStart, frameNumber, *stats);
 
     mViewer->renderingTraversals();
 
-    mLuaWorker->finishUpdate();
+    mLuaWorker->finishUpdate(frameStart, frameNumber, *stats);
 
     return true;
 }
@@ -910,7 +911,7 @@ void OMW::Engine::prepareEngine()
     mLuaManager->init();
 
     // starts a separate lua thread if "lua num threads" > 0
-    mLuaWorker = std::make_unique<MWLua::Worker>(*mLuaManager, *mViewer);
+    mLuaWorker = std::make_unique<MWLua::Worker>(*mLuaManager);
 }
 
 // Initialise and enter main loop.
diff --git a/apps/openmw/mwlua/worker.cpp b/apps/openmw/mwlua/worker.cpp
index 193d340208..5639cc89ed 100644
--- a/apps/openmw/mwlua/worker.cpp
+++ b/apps/openmw/mwlua/worker.cpp
@@ -7,13 +7,12 @@
 #include <components/debug/debuglog.hpp>
 #include <components/settings/values.hpp>
 
-#include <osgViewer/Viewer>
+#include <cassert>
 
 namespace MWLua
 {
-    Worker::Worker(LuaManager& manager, osgViewer::Viewer& viewer)
+    Worker::Worker(LuaManager& manager)
         : mManager(manager)
-        , mViewer(viewer)
     {
         if (Settings::lua().mLuaNumThreads > 0)
             mThread = std::thread([this] { run(); });
@@ -29,26 +28,26 @@ namespace MWLua
         }
     }
 
-    void Worker::allowUpdate()
+    void Worker::allowUpdate(osg::Timer_t frameStart, unsigned frameNumber, osg::Stats& stats)
     {
         if (!mThread)
             return;
         {
             std::lock_guard<std::mutex> lk(mMutex);
-            mUpdateRequest = true;
+            mUpdateRequest = UpdateRequest{ .mFrameStart = frameStart, .mFrameNumber = frameNumber, .mStats = &stats };
         }
         mCV.notify_one();
     }
 
-    void Worker::finishUpdate()
+    void Worker::finishUpdate(osg::Timer_t frameStart, unsigned frameNumber, osg::Stats& stats)
     {
         if (mThread)
         {
             std::unique_lock<std::mutex> lk(mMutex);
-            mCV.wait(lk, [&] { return !mUpdateRequest; });
+            mCV.wait(lk, [&] { return !mUpdateRequest.has_value(); });
         }
         else
-            update();
+            update(frameStart, frameNumber, stats);
     }
 
     void Worker::join()
@@ -64,12 +63,10 @@ namespace MWLua
         }
     }
 
-    void Worker::update()
+    void Worker::update(osg::Timer_t frameStart, unsigned frameNumber, osg::Stats& stats)
     {
-        const osg::Timer_t frameStart = mViewer.getStartTick();
-        const unsigned int frameNumber = mViewer.getFrameStamp()->getFrameNumber();
-        OMW::ScopedProfile<OMW::UserStatsType::Lua> profile(
-            frameStart, frameNumber, *osg::Timer::instance(), *mViewer.getViewerStats());
+        const osg::Timer* const timer = osg::Timer::instance();
+        OMW::ScopedProfile<OMW::UserStatsType::Lua> profile(frameStart, frameNumber, *timer, stats);
 
         mManager.update();
     }
@@ -79,20 +76,22 @@ namespace MWLua
         while (true)
         {
             std::unique_lock<std::mutex> lk(mMutex);
-            mCV.wait(lk, [&] { return mUpdateRequest || mJoinRequest; });
+            mCV.wait(lk, [&] { return mUpdateRequest.has_value() || mJoinRequest; });
             if (mJoinRequest)
                 break;
 
+            assert(mUpdateRequest.has_value());
+
             try
             {
-                update();
+                update(mUpdateRequest->mFrameStart, mUpdateRequest->mFrameNumber, *mUpdateRequest->mStats);
             }
-            catch (std::exception& e)
+            catch (const std::exception& e)
             {
                 Log(Debug::Error) << "Failed to update LuaManager: " << e.what();
             }
 
-            mUpdateRequest = false;
+            mUpdateRequest.reset();
             lk.unlock();
             mCV.notify_one();
         }
diff --git a/apps/openmw/mwlua/worker.hpp b/apps/openmw/mwlua/worker.hpp
index fed625e1f1..58d69afe71 100644
--- a/apps/openmw/mwlua/worker.hpp
+++ b/apps/openmw/mwlua/worker.hpp
@@ -1,14 +1,17 @@
 #ifndef OPENMW_MWLUA_WORKER_H
 #define OPENMW_MWLUA_WORKER_H
 
+#include <osg/Timer>
+#include <osg/ref_ptr>
+
 #include <condition_variable>
 #include <mutex>
 #include <optional>
 #include <thread>
 
-namespace osgViewer
+namespace osg
 {
-    class Viewer;
+    class Stats;
 }
 
 namespace MWLua
@@ -18,26 +21,32 @@ namespace MWLua
     class Worker
     {
     public:
-        explicit Worker(LuaManager& manager, osgViewer::Viewer& viewer);
+        explicit Worker(LuaManager& manager);
 
         ~Worker();
 
-        void allowUpdate();
+        void allowUpdate(osg::Timer_t frameStart, unsigned int frameNumber, osg::Stats& stats);
 
-        void finishUpdate();
+        void finishUpdate(osg::Timer_t frameStart, unsigned int frameNumber, osg::Stats& stats);
 
         void join();
 
     private:
-        void update();
+        struct UpdateRequest
+        {
+            osg::Timer_t mFrameStart;
+            unsigned mFrameNumber;
+            osg::ref_ptr<osg::Stats> mStats;
+        };
+
+        void update(osg::Timer_t frameStart, unsigned frameNumber, osg::Stats& stats);
 
         void run() noexcept;
 
         LuaManager& mManager;
-        osgViewer::Viewer& mViewer;
         std::mutex mMutex;
         std::condition_variable mCV;
-        bool mUpdateRequest = false;
+        std::optional<UpdateRequest> mUpdateRequest;
         bool mJoinRequest = false;
         std::optional<std::thread> mThread;
     };