Small delay before the loading screen shows

Kinda irritating to have the loading bar pop up for a fraction of a second.

apps/openmw/mwgui/loadingscreen.cpp

@@ -235,13 +235,38 @@ namespace MWGui
         draw();
     }
 
-    void LoadingScreen::draw()
+    bool LoadingScreen::needToDrawLoadingScreen()
     {
-        if (mTimer.time_m() > mLastRenderTime + (1.0/mTargetFrameRate) * 1000.0)
+        if ( mTimer.time_m() <= mLastRenderTime + (1.0/mTargetFrameRate) * 1000.0)
+            return false;
+
+        // the minimal delay before a loading screen shows
+        const float initialDelay = 0.05;
+
+        bool alreadyShown = (mLastRenderTime > mLoadingOnTime);
+        float diff = (mTimer.time_m() - mLoadingOnTime);
+
+        if (!alreadyShown)
         {
+            // bump the delay by the current progress - i.e. if during the initial delay the loading
+            // has almost finished, no point showing the loading screen now
+            diff -= mProgress / static_cast<float>(mProgressBar->getScrollRange()) * 100.f;
+        }
+
         bool showWallpaper = (MWBase::Environment::get().getStateManager()->getState()
                 == MWBase::StateManager::State_NoGame);
+        if (!showWallpaper && diff < initialDelay*1000)
+            return false;
+        return true;
+    }
 
+    void LoadingScreen::draw()
+    {
+        if (!needToDrawLoadingScreen())
+            return;
+
+        bool showWallpaper = (MWBase::Environment::get().getStateManager()->getState()
+                == MWBase::StateManager::State_NoGame);
         if (showWallpaper && mTimer.time_m() > mLastWallpaperChangeTime + 5000*1)
         {
             mLastWallpaperChangeTime = mTimer.time_m();
@@ -269,6 +294,5 @@ namespace MWGui
 
         mLastRenderTime = mTimer.time_m();
     }
-    }
 
 }

apps/openmw/mwgui/loadingscreen.hpp

@@ -52,6 +52,7 @@ namespace MWGui
 
     private:
         void findSplashScreens();
+        bool needToDrawLoadingScreen();
 
         const VFS::Manager* mVFS;
         osg::ref_ptr<osgViewer::Viewer> mViewer;