Preliminary rendering of QuadTreeWorld

components/terrain/quadtreenode.cpp

@@ -5,46 +5,7 @@
 #include <osgUtil/CullVisitor>
 
 #include "defs.hpp"
-
-namespace
-{
-
-    float distance(const osg::BoundingBox& box, const osg::Vec3f& v)
-    {
-        if (box.contains(v))
-            return 0;
-        else
-        {
-            osg::Vec3f maxDist(0,0,0);
-
-            if (v.x() < box.xMin())
-                maxDist.x() = box.xMin() - v.x();
-            else if (v.x() > box.xMax())
-                maxDist.x() = v.x() - box.xMax();
-
-            if (v.y() < box.yMin())
-                maxDist.y() = box.yMin() - v.y();
-            else if (v.y() > box.yMax())
-                maxDist.y() = v.y() - box.yMax();
-
-            if (v.z() < box.zMin())
-                maxDist.z() = box.zMin() - v.z();
-            else if (v.z() > box.zMax())
-                maxDist.z() = v.z() - box.zMax();
-
-            return maxDist.length();
-        }
-    }
-
-    int Log2( int n )
-    {
-        assert(n > 0);
-        int targetlevel = 0;
-        while (n >>= 1) ++targetlevel;
-        return targetlevel;
-    }
-
-}
+#include "viewdata.hpp"
 
 namespace Terrain
 {
@@ -104,6 +65,10 @@ QuadTreeNode::QuadTreeNode(QuadTreeNode* parent, ChildDirection direction, float
         mNeighbours[i] = 0;
 }
 
+QuadTreeNode::~QuadTreeNode()
+{
+}
+
 QuadTreeNode* QuadTreeNode::getParent()
 {
     return mParent;
@@ -125,18 +90,47 @@ void QuadTreeNode::initNeighbours()
 
 void QuadTreeNode::traverse(osg::NodeVisitor &nv)
 {
-    if (nv.getVisitorType() != osg::NodeVisitor::CULL_VISITOR)
-        return;
+    if (nv.getVisitorType() == osg::NodeVisitor::CULL_VISITOR)
+    {
+        osgUtil::CullVisitor* cv = static_cast<osgUtil::CullVisitor*>(&nv);
+
+        // do another culling test against bounding box as its much more accurate than the bounding sphere.
+        if (cv->isCulled(mBoundingBox))
+            return;
+    }
 
-    osgUtil::CullVisitor* cv = static_cast<osgUtil::CullVisitor*>(&nv);
+    if ((mLodCallback && mLodCallback->isSufficientDetail(this, nv)) || !getNumChildren())
+        getView(nv)->add(this);
+    else
+        osg::Group::traverse(nv);
+}
 
-    // do another culling test against bounding box as its much more accurate than the bounding sphere.
-    if (cv->isCulled(mBoundingBox))
-        return;
+void QuadTreeNode::setLodCallback(LodCallback *lodCallback)
+{
+    mLodCallback = lodCallback;
+}
 
-    //float dist = distance(getBoundingBox(), nv.getEyePoint());
+void QuadTreeNode::setViewDataMap(ViewDataMap *map)
+{
+    mViewDataMap = map;
+}
 
-    osg::Group::traverse(nv);
+ViewDataMap *QuadTreeNode::getViewDataMap()
+{
+    return mViewDataMap;
+}
+
+ViewData* QuadTreeNode::getView(osg::NodeVisitor &nv)
+{
+    if (nv.getVisitorType() == osg::NodeVisitor::CULL_VISITOR)
+    {
+        osgUtil::CullVisitor* cv = static_cast<osgUtil::CullVisitor*>(&nv);
+        return mViewDataMap->getViewData(cv->getCurrentCamera(), true);
+    }
+    else // INTERSECTION_VISITOR
+    {
+        return mViewDataMap->getViewData(&nv, false);
+    }
 }
 
 void QuadTreeNode::setBoundingBox(const osg::BoundingBox &boundingBox)

components/terrain/quadtreenode.hpp

@@ -17,10 +17,23 @@ namespace Terrain
         Root
     };
 
+    class QuadTreeNode;
+    class LodCallback : public osg::Referenced
+    {
+    public:
+        virtual ~LodCallback() {}
+
+        virtual bool isSufficientDetail(QuadTreeNode *node, osg::NodeVisitor &nv) = 0;
+    };
+
+    class ViewDataMap;
+    class ViewData;
+
     class QuadTreeNode : public osg::Group
     {
     public:
         QuadTreeNode(QuadTreeNode* parent, ChildDirection dir, float size, const osg::Vec2f& center);
+        virtual ~QuadTreeNode();
 
         QuadTreeNode* getParent();
 
@@ -49,6 +62,17 @@ namespace Terrain
 
         virtual void traverse(osg::NodeVisitor& nv);
 
+        /// Set the Lod callback to use for determining when to stop traversing further down the quad tree.
+        void setLodCallback(LodCallback* lodCallback);
+
+        /// Set the view data map that the finally used nodes for a given camera/intersection are pushed onto.
+        void setViewDataMap(ViewDataMap* map);
+
+        ViewDataMap* getViewDataMap();
+
+        /// Create or retrieve a view for the given traversal.
+        ViewData* getView(osg::NodeVisitor& nv);
+
     private:
         QuadTreeNode* mParent;
 
@@ -59,6 +83,10 @@ namespace Terrain
         osg::BoundingBox mBoundingBox;
         float mSize;
         osg::Vec2f mCenter;
+
+        osg::ref_ptr<LodCallback> mLodCallback;
+
+        osg::ref_ptr<ViewDataMap> mViewDataMap;
     };
 
 }

components/terrain/quadtreeworld.cpp

@@ -4,10 +4,8 @@
 
 #include "quadtreenode.hpp"
 #include "storage.hpp"
-
-
-#include <osg/io_utils>
-#include <osg/Timer>
+#include "viewdata.hpp"
+#include "chunkmanager.hpp"
 
 namespace
 {
@@ -29,11 +27,57 @@ namespace
         return 1 << depth;
     }
 
+    int Log2( unsigned int n )
+    {
+        int targetlevel = 0;
+        while (n >>= 1) ++targetlevel;
+        return targetlevel;
+    }
+
+    float distance(const osg::BoundingBox& box, const osg::Vec3f& v)
+    {
+        if (box.contains(v))
+            return 0;
+        else
+        {
+            osg::Vec3f maxDist(0,0,0);
+
+            if (v.x() < box.xMin())
+                maxDist.x() = box.xMin() - v.x();
+            else if (v.x() > box.xMax())
+                maxDist.x() = v.x() - box.xMax();
+
+            if (v.y() < box.yMin())
+                maxDist.y() = box.yMin() - v.y();
+            else if (v.y() > box.yMax())
+                maxDist.y() = v.y() - box.yMax();
+
+            if (v.z() < box.zMin())
+                maxDist.z() = box.zMin() - v.z();
+            else if (v.z() > box.zMax())
+                maxDist.z() = v.z() - box.zMax();
+
+            return maxDist.length();
+        }
+    }
+
 }
 
 namespace Terrain
 {
 
+class DefaultLodCallback : public LodCallback
+{
+public:
+    virtual bool isSufficientDetail(QuadTreeNode* node, osg::NodeVisitor& nv)
+    {
+        float dist = distance(node->getBoundingBox(), nv.getEyePoint());
+        int nativeLodLevel = Log2(static_cast<unsigned int>(node->getSize()*4));
+        int lodLevel = Log2(static_cast<unsigned int>(dist/2048.0));
+
+        return nativeLodLevel <= lodLevel;
+    }
+};
 
 class RootNode : public QuadTreeNode
 {
@@ -84,6 +128,7 @@ public:
         float centerY = (mMinY+mMaxY)/2.f + (size-origSizeY)/2.f;
 
         mRootNode = new RootNode(size, osg::Vec2f(centerX, centerY));
+        mRootNode->setViewDataMap(new ViewDataMap);
         addChildren(mRootNode);
 
         mRootNode->initNeighbours();
@@ -125,6 +170,8 @@ public:
         }
 
         osg::ref_ptr<QuadTreeNode> node = new QuadTreeNode(parent, direction, size, center);
+        node->setLodCallback(new DefaultLodCallback);
+        node->setViewDataMap(parent->getViewDataMap());
         parent->addChild(node);
 
         if (center.x() - size > mMaxX
@@ -190,10 +237,28 @@ QuadTreeWorld::~QuadTreeWorld()
 
 void QuadTreeWorld::accept(osg::NodeVisitor &nv)
 {
-    if (nv.getVisitorType() != osg::NodeVisitor::CULL_VISITOR && nv.getVisitorType() != osg::NodeVisitor::INTERSECTION_VISITOR)
+    if (nv.getVisitorType() != osg::NodeVisitor::CULL_VISITOR)// && nv.getVisitorType() != osg::NodeVisitor::INTERSECTION_VISITOR)
         return;
 
     mRootNode->traverse(nv);
+
+    ViewData* vd = mRootNode->getView(nv);
+
+    for (unsigned int i=0; i<vd->getNumEntries(); ++i)
+    {
+        ViewData::Entry& entry = vd->getEntry(i);
+        if (!entry.mRenderingNode)
+        {
+            int lod = Log2(int(entry.mNode->getSize()));
+            entry.mRenderingNode = mChunkManager->getChunk(entry.mNode->getSize(), entry.mNode->getCenter(), lod);
+        }
+
+        entry.mRenderingNode->accept(nv);
+    }
+
+    vd->reset(nv.getTraversalNumber());
+
+    mRootNode->getViewDataMap()->clearUnusedViews(nv.getTraversalNumber());
 }
 
 void QuadTreeWorld::loadCell(int x, int y)