forked from mirror/openmw-tes3mp
Add quad tree implementation (no rendering yet)
scrawl
8 years ago
parent
2d549d088e
commit
ce8c4ad4f5
@ -0,0 +1,169 @@
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#include "quadtreenode.hpp"
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#include <cassert>
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#include <osgUtil/CullVisitor>
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#include "defs.hpp"
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namespace
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{
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float distance(const osg::BoundingBox& box, const osg::Vec3f& v)
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{
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if (box.contains(v))
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return 0;
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else
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{
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osg::Vec3f maxDist(0,0,0);
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if (v.x() < box.xMin())
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maxDist.x() = box.xMin() - v.x();
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else if (v.x() > box.xMax())
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maxDist.x() = v.x() - box.xMax();
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if (v.y() < box.yMin())
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maxDist.y() = box.yMin() - v.y();
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else if (v.y() > box.yMax())
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maxDist.y() = v.y() - box.yMax();
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if (v.z() < box.zMin())
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maxDist.z() = box.zMin() - v.z();
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else if (v.z() > box.zMax())
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maxDist.z() = v.z() - box.zMax();
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return maxDist.length();
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}
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}
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int Log2( int n )
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{
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assert(n > 0);
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int targetlevel = 0;
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while (n >>= 1) ++targetlevel;
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return targetlevel;
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}
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}
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namespace Terrain
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{
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ChildDirection reflect(ChildDirection dir, Direction dir2)
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{
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assert(dir != Root);
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const int lookupTable[4][4] =
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{
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// NW NE SW SE
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{ SW, SE, NW, NE }, // N
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{ NE, NW, SE, SW }, // E
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{ SW, SE, NW, NE }, // S
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{ NE, NW, SE, SW } // W
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};
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return (ChildDirection)lookupTable[dir2][dir];
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}
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bool adjacent(ChildDirection dir, Direction dir2)
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{
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assert(dir != Root);
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const bool lookupTable[4][4] =
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{
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// NW NE SW SE
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{ true, true, false, false }, // N
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{ false, true, false, true }, // E
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{ false, false, true, true }, // S
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{ true, false, true, false } // W
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};
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return lookupTable[dir2][dir];
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}
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QuadTreeNode* searchNeighbour (QuadTreeNode* currentNode, Direction dir)
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{
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if (currentNode->getDirection() == Root)
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return NULL; // Arrived at root node, the root node does not have neighbours
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QuadTreeNode* nextNode;
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if (adjacent(currentNode->getDirection(), dir))
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nextNode = searchNeighbour(currentNode->getParent(), dir);
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else
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nextNode = currentNode->getParent();
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if (nextNode && nextNode->getNumChildren())
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return nextNode->getChild(reflect(currentNode->getDirection(), dir));
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else
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return NULL;
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}
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QuadTreeNode::QuadTreeNode(QuadTreeNode* parent, ChildDirection direction, float size, const osg::Vec2f& center)
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: mParent(parent)
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, mDirection(direction)
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, mSize(size)
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, mCenter(center)
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{
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for (unsigned int i=0; i<4; ++i)
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mNeighbours[i] = 0;
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}
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QuadTreeNode* QuadTreeNode::getParent()
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{
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return mParent;
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}
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QuadTreeNode *QuadTreeNode::getChild(unsigned int i)
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{
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return static_cast<QuadTreeNode*>(Group::getChild(i));
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}
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void QuadTreeNode::initNeighbours()
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{
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for (int i=0; i<4; ++i)
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mNeighbours[i] = searchNeighbour(this, (Direction)i);
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for (unsigned int i=0; i<getNumChildren(); ++i)
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getChild(i)->initNeighbours();
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}
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void QuadTreeNode::traverse(osg::NodeVisitor &nv)
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{
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if (nv.getVisitorType() != osg::NodeVisitor::CULL_VISITOR)
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return;
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osgUtil::CullVisitor* cv = static_cast<osgUtil::CullVisitor*>(&nv);
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// do another culling test against bounding box as its much more accurate than the bounding sphere.
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if (cv->isCulled(mBoundingBox))
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return;
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//float dist = distance(getBoundingBox(), nv.getEyePoint());
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osg::Group::traverse(nv);
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}
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void QuadTreeNode::setBoundingBox(const osg::BoundingBox &boundingBox)
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{
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mBoundingBox = boundingBox;
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dirtyBound();
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getBound();
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}
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const osg::BoundingBox &QuadTreeNode::getBoundingBox() const
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{
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return mBoundingBox;
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}
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osg::BoundingSphere QuadTreeNode::computeBound() const
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{
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return osg::BoundingSphere(mBoundingBox);
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}
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float QuadTreeNode::getSize() const
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{
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return mSize;
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}
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const osg::Vec2f &QuadTreeNode::getCenter() const
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{
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return mCenter;
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}
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}
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@ -0,0 +1,66 @@
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#ifndef OPENMW_COMPONENTS_TERRAIN_QUADTREENODE_H
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#define OPENMW_COMPONENTS_TERRAIN_QUADTREENODE_H
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#include <osg/Group>
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#include "defs.hpp"
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namespace Terrain
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{
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enum ChildDirection
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{
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NW = 0,
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NE = 1,
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SW = 2,
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SE = 3,
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Root
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};
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class QuadTreeNode : public osg::Group
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{
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public:
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QuadTreeNode(QuadTreeNode* parent, ChildDirection dir, float size, const osg::Vec2f& center);
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QuadTreeNode* getParent();
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QuadTreeNode* getChild(unsigned int i);
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using osg::Group::getNumChildren;
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/// Returns our direction relative to the parent node, or Root if we are the root node.
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ChildDirection getDirection() { return mDirection; }
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/// Get neighbour node in this direction
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QuadTreeNode* getNeighbour (Direction dir);
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/// Initialize neighbours - do this after the quadtree is built
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void initNeighbours();
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void setBoundingBox(const osg::BoundingBox& boundingBox);
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const osg::BoundingBox& getBoundingBox() const;
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virtual osg::BoundingSphere computeBound() const;
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/// size in cell coordinates
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float getSize() const;
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/// center in cell coordinates
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const osg::Vec2f& getCenter() const;
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virtual void traverse(osg::NodeVisitor& nv);
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private:
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QuadTreeNode* mParent;
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QuadTreeNode* mNeighbours[4];
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ChildDirection mDirection;
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osg::BoundingBox mBoundingBox;
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float mSize;
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osg::Vec2f mCenter;
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};
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}
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#endif
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@ -0,0 +1,227 @@
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#include "quadtreeworld.hpp"
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#include <components/sceneutil/workqueue.hpp>
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#include "quadtreenode.hpp"
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#include "storage.hpp"
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#include <osg/io_utils>
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#include <osg/Timer>
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namespace
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{
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bool isPowerOfTwo(int x)
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{
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return ( (x > 0) && ((x & (x - 1)) == 0) );
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}
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int nextPowerOfTwo (int v)
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{
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if (isPowerOfTwo(v)) return v;
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int depth=0;
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while(v)
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{
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v >>= 1;
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depth++;
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}
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return 1 << depth;
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}
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}
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namespace Terrain
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{
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class RootNode : public QuadTreeNode
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{
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public:
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RootNode(float size, const osg::Vec2f& center)
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: QuadTreeNode(NULL, Root, size, center)
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, mWorld(NULL)
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{
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}
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void setWorld(QuadTreeWorld* world)
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{
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mWorld = world;
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}
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virtual void accept(osg::NodeVisitor &nv)
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{
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nv.pushOntoNodePath(this);
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mWorld->accept(nv);
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nv.popFromNodePath();
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}
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private:
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QuadTreeWorld* mWorld;
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};
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class BuildQuadTreeItem : public SceneUtil::WorkItem
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{
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public:
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BuildQuadTreeItem(Terrain::Storage* storage, float minSize)
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: mStorage(storage)
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, mMinX(0.f), mMaxX(0.f), mMinY(0.f), mMaxY(0.f)
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, mMinSize(minSize)
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{
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}
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virtual void doWork()
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{
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mStorage->getBounds(mMinX, mMaxX, mMinY, mMaxY);
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int origSizeX = static_cast<int>(mMaxX - mMinX);
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int origSizeY = static_cast<int>(mMaxY - mMinY);
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// Dividing a quad tree only works well for powers of two, so round up to the nearest one
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int size = nextPowerOfTwo(std::max(origSizeX, origSizeY));
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float centerX = (mMinX+mMaxX)/2.f + (size-origSizeX)/2.f;
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float centerY = (mMinY+mMaxY)/2.f + (size-origSizeY)/2.f;
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mRootNode = new RootNode(size, osg::Vec2f(centerX, centerY));
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addChildren(mRootNode);
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mRootNode->initNeighbours();
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}
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void addChildren(QuadTreeNode* parent)
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{
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float halfSize = parent->getSize()/2.f;
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osg::BoundingBox boundingBox;
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for (unsigned int i=0; i<4; ++i)
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{
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QuadTreeNode* child = addChild(parent, static_cast<ChildDirection>(i), halfSize);
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if (child)
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boundingBox.expandBy(child->getBoundingBox());
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}
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parent->setBoundingBox(boundingBox);
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}
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QuadTreeNode* addChild(QuadTreeNode* parent, ChildDirection direction, float size)
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{
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osg::Vec2f center;
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switch (direction)
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{
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case SW:
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center = parent->getCenter() + osg::Vec2f(-size/2.f,-size/2.f);
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break;
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case SE:
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center = parent->getCenter() + osg::Vec2f(size/2.f, -size/2.f);
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break;
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case NW:
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center = parent->getCenter() + osg::Vec2f(-size/2.f, size/2.f);
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break;
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case NE:
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center = parent->getCenter() + osg::Vec2f(size/2.f, size/2.f);
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break;
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default:
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break;
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}
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osg::ref_ptr<QuadTreeNode> node = new QuadTreeNode(parent, direction, size, center);
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parent->addChild(node);
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if (center.x() - size > mMaxX
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|| center.x() + size < mMinX
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|| center.y() - size > mMaxY
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|| center.y() + size < mMinY )
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// Out of bounds of the actual terrain - this will happen because
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// we rounded the size up to the next power of two
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{
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// Still create and return an empty node so as to not break the assumption that each QuadTreeNode has either 4 or 0 children.
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return node;
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}
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if (node->getSize() <= mMinSize)
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{
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// We arrived at a leaf
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float minZ,maxZ;
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if (mStorage->getMinMaxHeights(size, center, minZ, maxZ))
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{
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float cellWorldSize = mStorage->getCellWorldSize();
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osg::BoundingBox boundingBox(osg::Vec3f((center.x()-size)*cellWorldSize, (center.y()-size)*cellWorldSize, minZ),
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osg::Vec3f((center.x()+size)*cellWorldSize, (center.y()+size)*cellWorldSize, maxZ));
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node->setBoundingBox(boundingBox);
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}
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return node;
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}
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else
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{
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addChildren(node);
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return node;
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}
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}
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osg::ref_ptr<RootNode> getRootNode()
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{
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return mRootNode;
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}
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private:
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Terrain::Storage* mStorage;
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float mMinX, mMaxX, mMinY, mMaxY;
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float mMinSize;
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osg::ref_ptr<RootNode> mRootNode;
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};
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QuadTreeWorld::QuadTreeWorld(SceneUtil::WorkQueue* workQueue, osg::Group *parent, osg::Group *compileRoot, Resource::ResourceSystem *resourceSystem, Storage *storage, int nodeMask, int preCompileMask)
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: World(parent, compileRoot, resourceSystem, storage, nodeMask, preCompileMask)
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, mWorkQueue(workQueue)
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, mQuadTreeBuilt(false)
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{
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}
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QuadTreeWorld::~QuadTreeWorld()
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{
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if (mWorkItem)
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{
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mWorkItem->abort();
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mWorkItem->waitTillDone();
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}
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}
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void QuadTreeWorld::accept(osg::NodeVisitor &nv)
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{
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if (nv.getVisitorType() != osg::NodeVisitor::CULL_VISITOR && nv.getVisitorType() != osg::NodeVisitor::INTERSECTION_VISITOR)
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return;
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mRootNode->traverse(nv);
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}
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void QuadTreeWorld::loadCell(int x, int y)
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{
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if (mQuadTreeBuilt && !mRootNode)
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{
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mRootNode = mWorkItem->getRootNode();
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mRootNode->setWorld(this);
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mTerrainRoot->addChild(mRootNode);
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mWorkItem = NULL;
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}
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}
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osg::ref_ptr<osg::Node> QuadTreeWorld::cacheCell(int x, int y)
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{
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if (!mQuadTreeBuilt)
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{
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const float minSize = 1/4.f;
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mWorkItem = new BuildQuadTreeItem(mStorage, minSize);
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mWorkQueue->addWorkItem(mWorkItem);
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mWorkItem->waitTillDone();
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mQuadTreeBuilt = true;
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}
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return NULL;
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}
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}
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@ -0,0 +1,47 @@
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#ifndef COMPONENTS_TERRAIN_QUADTREEWORLD_H
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#define COMPONENTS_TERRAIN_QUADTREEWORLD_H
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#include <map>
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#include "world.hpp"
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namespace SceneUtil
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{
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class WorkQueue;
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}
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namespace osg
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{
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class NodeVisitor;
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}
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namespace Terrain
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{
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class RootNode;
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class BuildQuadTreeItem;
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/// @brief Terrain implementation that loads cells into a Quad Tree, with geometry LOD and texture LOD. The entire world is displayed at all times.
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class QuadTreeWorld : public Terrain::World
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{
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public:
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QuadTreeWorld(SceneUtil::WorkQueue* workQueue, osg::Group* parent, osg::Group* compileRoot, Resource::ResourceSystem* resourceSystem, Storage* storage, int nodeMask, int preCompileMask=~0);
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~QuadTreeWorld();
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void accept(osg::NodeVisitor& nv);
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virtual void loadCell(int x, int y);
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virtual osg::ref_ptr<osg::Node> cacheCell(int x, int y);
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private:
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osg::ref_ptr<RootNode> mRootNode;
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osg::ref_ptr<SceneUtil::WorkQueue> mWorkQueue;
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osg::ref_ptr<BuildQuadTreeItem> mWorkItem;
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bool mQuadTreeBuilt;
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};
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}
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#endif
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