From 640420eaaa61b38307b16aa6e5b14180f26bc4b8 Mon Sep 17 00:00:00 2001
From: Mads Buvik Sandvei <madssandvei@protonmail.com>
Date: Wed, 16 Dec 2020 21:46:52 +0100
Subject: [PATCH 1/2] No longer delete and recreate
 CopyFramebufferToTextureCallback, remove oneshot functionality. Instead just
 remove the callback after the traversals. Use addInitialDrawCallback instead
 of setInitialDrawCallback to avoid messing with existing callbacks.

---
 apps/openmw/mwgui/loadingscreen.cpp | 17 +++++++++--------
 apps/openmw/mwgui/loadingscreen.hpp |  2 ++
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/apps/openmw/mwgui/loadingscreen.cpp b/apps/openmw/mwgui/loadingscreen.cpp
index cd0384bb0..2e2de578e 100644
--- a/apps/openmw/mwgui/loadingscreen.cpp
+++ b/apps/openmw/mwgui/loadingscreen.cpp
@@ -137,15 +137,11 @@ namespace MWGui
     public:
         CopyFramebufferToTextureCallback(osg::Texture2D* texture)
             : mTexture(texture)
-            , oneshot(true)
         {
         }
 
         void operator () (osg::RenderInfo& renderInfo) const override
         {
-            if (!oneshot)
-                return;
-            oneshot = false;
             int w = renderInfo.getCurrentCamera()->getViewport()->width();
             int h = renderInfo.getCurrentCamera()->getViewport()->height();
             mTexture->copyTexImage2D(*renderInfo.getState(), 0, 0, w, h);
@@ -153,7 +149,6 @@ namespace MWGui
 
     private:
         osg::ref_ptr<osg::Texture2D> mTexture;
-        mutable bool oneshot;
     };
 
     class DontComputeBoundCallback : public osg::Node::ComputeBoundingSphereCallback
@@ -322,9 +317,12 @@ namespace MWGui
             mGuiTexture.reset(new osgMyGUI::OSGTexture(mTexture));
         }
 
-        // Notice that the next time this is called, the current CopyFramebufferToTextureCallback will be deleted
-        // so there's no memory leak as at most one object of type CopyFramebufferToTextureCallback is allocated at a time.
-        mViewer->getCamera()->setInitialDrawCallback(new CopyFramebufferToTextureCallback(mTexture));
+        if (!mCopyFramebufferToTextureCallback)
+        {
+            mCopyFramebufferToTextureCallback = new CopyFramebufferToTextureCallback(mTexture);
+        }
+
+        mViewer->getCamera()->addInitialDrawCallback(mCopyFramebufferToTextureCallback);
 
         mBackgroundImage->setBackgroundImage("");
         mBackgroundImage->setVisible(false);
@@ -367,6 +365,9 @@ namespace MWGui
         mViewer->renderingTraversals();
         mViewer->advance(mViewer->getFrameStamp()->getSimulationTime());
 
+        if(mCopyFramebufferToTextureCallback)
+            mViewer->getCamera()->removeInitialDrawCallback(mCopyFramebufferToTextureCallback);
+
         mLastRenderTime = mTimer.time_m();
     }
 
diff --git a/apps/openmw/mwgui/loadingscreen.hpp b/apps/openmw/mwgui/loadingscreen.hpp
index 2577827aa..ac911ab60 100644
--- a/apps/openmw/mwgui/loadingscreen.hpp
+++ b/apps/openmw/mwgui/loadingscreen.hpp
@@ -28,6 +28,7 @@ namespace Resource
 namespace MWGui
 {
     class BackgroundImage;
+    class CopyFramebufferToTextureCallback;
 
     class LoadingScreen : public WindowBase, public Loading::Listener
     {
@@ -84,6 +85,7 @@ namespace MWGui
         std::vector<std::string> mSplashScreens;
 
         osg::ref_ptr<osg::Texture2D> mTexture;
+        osg::ref_ptr<CopyFramebufferToTextureCallback> mCopyFramebufferToTextureCallback;
         std::unique_ptr<MyGUI::ITexture> mGuiTexture;
 
         void changeWallpaper();

From bc961a13f54842aa1dd75a459fabfe98ccce2cad Mon Sep 17 00:00:00 2001
From: Mads Buvik Sandvei <madssandvei@protonmail.com>
Date: Wed, 16 Dec 2020 22:03:16 +0100
Subject: [PATCH 2/2] avoid redundant calls to removeInitialDrawCallback

---
 apps/openmw/mwgui/loadingscreen.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/apps/openmw/mwgui/loadingscreen.cpp b/apps/openmw/mwgui/loadingscreen.cpp
index 2e2de578e..20586ef4a 100644
--- a/apps/openmw/mwgui/loadingscreen.cpp
+++ b/apps/openmw/mwgui/loadingscreen.cpp
@@ -365,8 +365,11 @@ namespace MWGui
         mViewer->renderingTraversals();
         mViewer->advance(mViewer->getFrameStamp()->getSimulationTime());
 
-        if(mCopyFramebufferToTextureCallback)
+        if (mCopyFramebufferToTextureCallback)
+        {
             mViewer->getCamera()->removeInitialDrawCallback(mCopyFramebufferToTextureCallback);
+            mCopyFramebufferToTextureCallback = nullptr;
+        }
 
         mLastRenderTime = mTimer.time_m();
     }