From 8c151364df0b7a50b6ba1cd6a7409966a05d5c64 Mon Sep 17 00:00:00 2001
From: scrawl <scrawl@baseoftrash.de>
Date: Thu, 9 Mar 2017 00:01:13 +0100
Subject: [PATCH] Add special handling for CullVisitor to QuadTreeWorld.

- Cull only against bounding box, not bounding sphere, as this appears to perform better.
- Also traverse into non visible nodes to compute their LOD, this is to avoid nodes having to be loaded in when the player turns the view around, and will avoid unnecessary refs/unrefs of rendering data in the View. This should probably be turned off at some point for static cameras, such as the local maps.
---
 components/terrain/quadtreenode.cpp  |  7 +++++-
 components/terrain/quadtreenode.hpp  |  2 ++
 components/terrain/quadtreeworld.cpp | 33 +++++++++++++++++++++++++---
 components/terrain/viewdata.cpp      | 12 +++++-----
 components/terrain/viewdata.hpp      |  5 +++--
 5 files changed, 48 insertions(+), 11 deletions(-)

diff --git a/components/terrain/quadtreenode.cpp b/components/terrain/quadtreenode.cpp
index 5eb59a6a21..d556bb4fea 100644
--- a/components/terrain/quadtreenode.cpp
+++ b/components/terrain/quadtreenode.cpp
@@ -104,7 +104,7 @@ void QuadTreeNode::traverse(osg::NodeVisitor &nv)
     }
 
     if ((mLodCallback && mLodCallback->isSufficientDetail(this, nv)) || !getNumChildren())
-        getView(nv)->add(this);
+        getView(nv)->add(this, true);
     else
         osg::Group::traverse(nv);
 }
@@ -114,6 +114,11 @@ void QuadTreeNode::setLodCallback(LodCallback *lodCallback)
     mLodCallback = lodCallback;
 }
 
+LodCallback *QuadTreeNode::getLodCallback()
+{
+    return mLodCallback;
+}
+
 void QuadTreeNode::setViewDataMap(ViewDataMap *map)
 {
     mViewDataMap = map;
diff --git a/components/terrain/quadtreenode.hpp b/components/terrain/quadtreenode.hpp
index 1d996487e2..c7a6a09d9c 100644
--- a/components/terrain/quadtreenode.hpp
+++ b/components/terrain/quadtreenode.hpp
@@ -66,6 +66,8 @@ namespace Terrain
         /// Set the Lod callback to use for determining when to stop traversing further down the quad tree.
         void setLodCallback(LodCallback* lodCallback);
 
+        LodCallback* getLodCallback();
+
         /// Set the view data map that the finally used nodes for a given camera/intersection are pushed onto.
         void setViewDataMap(ViewDataMap* map);
 
diff --git a/components/terrain/quadtreeworld.cpp b/components/terrain/quadtreeworld.cpp
index 24f24ff371..9c27fa1ad4 100644
--- a/components/terrain/quadtreeworld.cpp
+++ b/components/terrain/quadtreeworld.cpp
@@ -1,5 +1,7 @@
 #include "quadtreeworld.hpp"
 
+#include <osgUtil/CullVisitor>
+
 #include <components/sceneutil/workqueue.hpp>
 
 #include "quadtreenode.hpp"
@@ -235,15 +237,39 @@ QuadTreeWorld::~QuadTreeWorld()
     }
 }
 
+
+void traverse(QuadTreeNode* node, ViewData* vd, osgUtil::CullVisitor* cv, bool visible)
+{
+    if (!node->hasValidBounds())
+        return;
+
+    visible = visible && !cv->isCulled(node->getBoundingBox());
+    bool stopTraversal = (node->getLodCallback() && node->getLodCallback()->isSufficientDetail(node, *cv)) || !node->getNumChildren();
+
+    if (stopTraversal)
+        vd->add(node, visible);
+    else
+    {
+        for (unsigned int i=0; i<node->getNumChildren(); ++i)
+            traverse(node->getChild(i), vd, cv, visible);
+    }
+}
+
 void QuadTreeWorld::accept(osg::NodeVisitor &nv)
 {
     if (nv.getVisitorType() != osg::NodeVisitor::CULL_VISITOR)// && nv.getVisitorType() != osg::NodeVisitor::INTERSECTION_VISITOR)
         return;
 
-    mRootNode->traverse(nv);
-
     ViewData* vd = mRootNode->getView(nv);
 
+    if (nv.getVisitorType() == osg::NodeVisitor::CULL_VISITOR)
+    {
+        osgUtil::CullVisitor* cv = static_cast<osgUtil::CullVisitor*>(&nv);
+        traverse(mRootNode.get(), vd, cv, true);
+    }
+    else
+        mRootNode->traverse(nv);
+
     for (unsigned int i=0; i<vd->getNumEntries(); ++i)
     {
         ViewData::Entry& entry = vd->getEntry(i);
@@ -253,7 +279,8 @@ void QuadTreeWorld::accept(osg::NodeVisitor &nv)
             entry.mRenderingNode = mChunkManager->getChunk(entry.mNode->getSize(), entry.mNode->getCenter(), lod);
         }
 
-        entry.mRenderingNode->accept(nv);
+        if (entry.mVisible)
+            entry.mRenderingNode->accept(nv);
     }
 
     vd->reset(nv.getTraversalNumber());
diff --git a/components/terrain/viewdata.cpp b/components/terrain/viewdata.cpp
index aff20cd54b..ce89150c19 100644
--- a/components/terrain/viewdata.cpp
+++ b/components/terrain/viewdata.cpp
@@ -12,14 +12,14 @@ ViewData::ViewData()
 
 }
 
-void ViewData::add(QuadTreeNode *node)
+void ViewData::add(QuadTreeNode *node, bool visible)
 {
     int index = mNumEntries++;
 
     mEntries.resize(index+1);
 
     Entry& entry = mEntries[index];
-    if (entry.set(node))
+    if (entry.set(node, visible))
         mChanged = true;
 }
 
@@ -37,7 +37,7 @@ void ViewData::reset(unsigned int frame)
 {
     // clear any unused entries
     for (unsigned int i=mNumEntries; i<mEntries.size(); ++i)
-        mEntries[i].set(NULL);
+        mEntries[i].set(NULL, false);
 
     // reset index for next frame
     mNumEntries = 0;
@@ -48,19 +48,21 @@ void ViewData::reset(unsigned int frame)
 void ViewData::clear()
 {
     for (unsigned int i=0; i<mEntries.size(); ++i)
-        mEntries[i].set(NULL);
+        mEntries[i].set(NULL, false);
     mNumEntries = 0;
     mFrameLastUsed = 0;
 }
 
 ViewData::Entry::Entry()
     : mNode(NULL)
+    , mVisible(true)
 {
 
 }
 
-bool ViewData::Entry::set(QuadTreeNode *node)
+bool ViewData::Entry::set(QuadTreeNode *node, bool visible)
 {
+    mVisible = visible;
     if (node == mNode)
         return false;
     else
diff --git a/components/terrain/viewdata.hpp b/components/terrain/viewdata.hpp
index 0ceb8313f8..8e2e4fbd96 100644
--- a/components/terrain/viewdata.hpp
+++ b/components/terrain/viewdata.hpp
@@ -16,7 +16,7 @@ namespace Terrain
     public:
         ViewData();
 
-        void add(QuadTreeNode* node);
+        void add(QuadTreeNode* node, bool visible);
 
         void reset(unsigned int frame);
 
@@ -26,9 +26,10 @@ namespace Terrain
         {
             Entry();
 
-            bool set(QuadTreeNode* node);
+            bool set(QuadTreeNode* node, bool visible);
 
             QuadTreeNode* mNode;
+            bool mVisible;
 
             osg::ref_ptr<osg::Node> mRenderingNode;
         };