From a939cb669256b49efb3381edfdc9494a283f0b53 Mon Sep 17 00:00:00 2001
From: Andrei Kortunov <andrei.kortunov@yandex.ru>
Date: Sun, 9 May 2021 14:10:35 +0400
Subject: [PATCH 1/2] Skip hidden nodes for ObjectPaging

---
 apps/openmw/mwrender/objectpaging.cpp | 29 ++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/apps/openmw/mwrender/objectpaging.cpp b/apps/openmw/mwrender/objectpaging.cpp
index 064d3aa35..c36ceefe2 100644
--- a/apps/openmw/mwrender/objectpaging.cpp
+++ b/apps/openmw/mwrender/objectpaging.cpp
@@ -105,6 +105,7 @@ namespace MWRender
         bool mOptimizeBillboards = true;
         float mSqrDistance = 0.f;
         osg::Vec3f mViewVector;
+        osg::Node::NodeMask mCopyMask = ~0u;
         mutable std::vector<const osg::Node*> mNodePath;
 
         void copy(const osg::Node* toCopy, osg::Group* attachTo)
@@ -121,6 +122,9 @@ namespace MWRender
 
         osg::Node* operator() (const osg::Node* node) const override
         {
+            if (!(node->getNodeMask() & mCopyMask))
+                return nullptr;
+
             if (const osg::Drawable* d = node->asDrawable())
                 return operator()(d);
 
@@ -224,6 +228,9 @@ namespace MWRender
         }
         osg::Drawable* operator() (const osg::Drawable* drawable) const override
         {
+            if (!(drawable->getNodeMask() & mCopyMask))
+                return nullptr;
+
             if (dynamic_cast<const osgParticle::ParticleSystem*>(drawable))
                 return nullptr;
 
@@ -261,9 +268,10 @@ namespace MWRender
     class AnalyzeVisitor : public osg::NodeVisitor
     {
     public:
-        AnalyzeVisitor()
+        AnalyzeVisitor(osg::Node::NodeMask analyzeMask)
          : osg::NodeVisitor(TRAVERSE_ALL_CHILDREN)
-         , mCurrentStateSet(nullptr) {}
+         , mCurrentStateSet(nullptr)
+         , mAnalyzeMask(analyzeMask) {}
 
         typedef std::unordered_map<osg::StateSet*, unsigned int> StateSetCounter;
         struct Result
@@ -274,12 +282,18 @@ namespace MWRender
 
         void apply(osg::Node& node) override
         {
+            if (!(node.getNodeMask() & mAnalyzeMask))
+                return;
+
             if (node.getStateSet())
                 mCurrentStateSet = node.getStateSet();
             traverse(node);
         }
         void apply(osg::Geometry& geom) override
         {
+            if (!(geom.getNodeMask() & mAnalyzeMask))
+                return;
+
             if (osg::Array* array = geom.getVertexArray())
                 mResult.mNumVerts += array->getNumElements();
 
@@ -313,6 +327,7 @@ namespace MWRender
         Result mResult;
         osg::StateSet* mCurrentStateSet;
         StateSetCounter mGlobalStateSetCounter;
+        osg::Node::NodeMask mAnalyzeMask;
     };
 
     class DebugVisitor : public osg::NodeVisitor
@@ -438,7 +453,14 @@ namespace MWRender
         typedef std::map<osg::ref_ptr<const osg::Node>, InstanceList> NodeMap;
         NodeMap nodes;
         osg::ref_ptr<RefnumSet> refnumSet = activeGrid ? new RefnumSet : nullptr;
-        AnalyzeVisitor analyzeVisitor;
+
+        // Mask_UpdateVisitor is used in such cases in NIF loader:
+        // 1. For collision nodes, which is not supposed to be rendered.
+        // 2. For nodes masked via Flag_Hidden (VisController can change this flag value at runtime).
+        // Since ObjectPaging does not handle VisController, we can just ignore both types of nodes.
+        constexpr auto copyMask = ~Mask_UpdateVisitor;
+
+        AnalyzeVisitor analyzeVisitor(copyMask);
         float minSize = mMinSize;
         if (mMinSizeMergeFactor)
             minSize *= mMinSizeMergeFactor;
@@ -525,6 +547,7 @@ namespace MWRender
         osg::ref_ptr<Resource::TemplateMultiRef> templateRefs = new Resource::TemplateMultiRef;
         osgUtil::StateToCompile stateToCompile(0, nullptr);
         CopyOp copyop;
+        copyop.mCopyMask = copyMask;
         for (const auto& pair : nodes)
         {
             const osg::Node* cnode = pair.first;

From 132fedf2909a209afc04281b1a328d279e1ea58b Mon Sep 17 00:00:00 2001
From: Andrei Kortunov <andrei.kortunov@yandex.ru>
Date: Sun, 9 May 2021 15:43:13 +0400
Subject: [PATCH 2/2] Analyze only used LOD levels in ObjectPaging

---
 apps/openmw/mwrender/objectpaging.cpp | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/apps/openmw/mwrender/objectpaging.cpp b/apps/openmw/mwrender/objectpaging.cpp
index c36ceefe2..4217c4714 100644
--- a/apps/openmw/mwrender/objectpaging.cpp
+++ b/apps/openmw/mwrender/objectpaging.cpp
@@ -271,6 +271,7 @@ namespace MWRender
         AnalyzeVisitor(osg::Node::NodeMask analyzeMask)
          : osg::NodeVisitor(TRAVERSE_ALL_CHILDREN)
          , mCurrentStateSet(nullptr)
+         , mCurrentDistance(0.f)
          , mAnalyzeMask(analyzeMask) {}
 
         typedef std::unordered_map<osg::StateSet*, unsigned int> StateSetCounter;
@@ -287,6 +288,22 @@ namespace MWRender
 
             if (node.getStateSet())
                 mCurrentStateSet = node.getStateSet();
+
+            if (osg::Switch* sw = node.asSwitch())
+            {
+                for (unsigned int i=0; i<sw->getNumChildren(); ++i)
+                    if (sw->getValue(i))
+                        traverse(*sw->getChild(i));
+                return;
+            }
+            if (osg::LOD* lod = dynamic_cast<osg::LOD*>(&node))
+            {
+                for (unsigned int i=0; i<lod->getNumChildren(); ++i)
+                    if (lod->getMinRange(i) * lod->getMinRange(i) <= mCurrentDistance && mCurrentDistance < lod->getMaxRange(i) * lod->getMaxRange(i))
+                        traverse(*lod->getChild(i));
+                return;
+            }
+
             traverse(node);
         }
         void apply(osg::Geometry& geom) override
@@ -327,6 +344,7 @@ namespace MWRender
         Result mResult;
         osg::StateSet* mCurrentStateSet;
         StateSetCounter mGlobalStateSetCounter;
+        float mCurrentDistance;
         osg::Node::NodeMask mAnalyzeMask;
     };
 
@@ -530,6 +548,7 @@ namespace MWRender
                 continue;
             }
 
+            analyzeVisitor.mCurrentDistance = dSqr;
             auto emplaced = nodes.emplace(cnode, InstanceList());
             if (emplaced.second)
             {