139 lines
5.0 KiB
C++
139 lines
5.0 KiB
C++
// Copyright (C) 2008 Tim Moore
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as
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// published by the Free Software Foundation; either version 2 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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#ifndef SIMGEAR_QUADTREEBUILDER_HXX
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#define SIMGEAR_QUADTREEBUILDER_HXX 1
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#include <algorithm>
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#include <functional>
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#include <vector>
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#include <osg/BoundingBox>
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#include <osg/ref_ptr>
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#include <osg/Node>
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#include <osg/Group>
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#include <osg/Matrix>
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#include <osg/Vec2>
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#include <osg/LOD>
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#include "VectorArrayAdapter.hxx"
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namespace simgear
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{
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typedef std::map<osg::ref_ptr<osg::Node>,int> LodMap;
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// Create a quad tree based on x, y extents
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template <typename LeafType, typename ObjectType, typename MakeLeaf,
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typename AddLeafObject, typename GetObjectLocalCoords>
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class QuadTreeBuilder {
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public:
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QuadTreeBuilder(const GetObjectLocalCoords& getLocalCoords,
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const AddLeafObject& addLeafObject, int depth = 2,
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const MakeLeaf& makeLeaf = MakeLeaf()) :
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_root(new osg::Group), _depth(depth),
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_dimension(1 << depth), _leafStorage(_dimension * _dimension),
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_leaves(_leafStorage, _dimension),
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_leafParents(_leafParentStorage, _dimension / 2),
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_getLocalCoords(getLocalCoords),
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_addLeafObject(addLeafObject), _makeLeaf(makeLeaf)
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{
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using namespace std;
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using namespace osg;
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vector<Group*> parentNodes(1);
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parentNodes[0] = _root.get();
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unsigned leafDim = 2;
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for (int i = 0; i < depth - 1; ++i, leafDim *= 2) {
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VectorArrayAdapter<vector<Group*> > parents(parentNodes, leafDim / 2);
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vector<Group*> interiorNodes(leafDim * leafDim);
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VectorArrayAdapter<vector<Group*> > interiors(interiorNodes, leafDim);
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for (unsigned j = 0; j < leafDim; ++j) {
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for (unsigned k = 0; k < leafDim; ++k) {
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interiors(j, k) = new Group;
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parents(j / 2, k / 2)->addChild(interiors(j, k));
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}
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}
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parentNodes.swap(interiorNodes);
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}
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// Save leaf parents for later when we add leaves
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_leafParentStorage = parentNodes;
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}
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osg::Vec2 getMin() { return _min; }
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void setMin(const osg::Vec2& min) { _min = min; }
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osg::Vec2 getMax() { return _max; }
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void setMax(const osg::Vec2& max) { _max = max; }
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~QuadTreeBuilder() {}
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osg::Group* getRoot() { return _root.get(); }
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void addNode(ObjectType& obj)
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{
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using namespace osg;
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const Vec3 center(_getLocalCoords(obj));
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int x = 0;
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if (_max.x() != _min.x())
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x = (int)(_dimension * (center.x() - _min.x())
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/ (_max.x() - _min.x()));
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x = clampTo(x, 0, (_dimension - 1));
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int y = 0;
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if (_max.y() != _min.y())
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y = (int)(_dimension * (center.y() - _min.y())
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/ (_max.y() - _min.y()));
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y = clampTo(y, 0, (_dimension -1));
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if (!_leaves(y, x)) {
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_leaves(y, x) = _makeLeaf();
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_leafParents(y / 2, x / 2)->addChild(_leaves(y, x));
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}
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_addLeafObject(_leaves(y, x), obj);
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}
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// STL craziness
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struct AddNode
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{
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AddNode(QuadTreeBuilder* qt) : _qt(qt) {}
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AddNode(const AddNode& rhs) : _qt(rhs._qt) {}
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void operator() (ObjectType& obj) const { _qt->addNode(obj); }
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QuadTreeBuilder *_qt;
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};
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// Make a quadtree of nodes from a map of nodes and LOD values
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template <typename ForwardIterator>
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void buildQuadTree(const ForwardIterator& begin,
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const ForwardIterator& end)
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{
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using namespace osg;
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BoundingBox extents;
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for (ForwardIterator iter = begin; iter != end; ++iter) {
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const Vec3 center = _getLocalCoords(*iter);
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extents.expandBy(center);
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}
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_min = Vec2(extents.xMin(), extents.yMin());
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_max = Vec2(extents.xMax(), extents.yMax());
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std::for_each(begin, end, AddNode(this));
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}
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protected:
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typedef std::vector<LeafType> LeafVector;
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osg::ref_ptr<osg::Group> _root;
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osg::Vec2 _min;
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osg::Vec2 _max;
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int _depth;
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int _dimension;
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LeafVector _leafStorage;
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VectorArrayAdapter<LeafVector> _leaves;
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std::vector<osg::Group*> _leafParentStorage;
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VectorArrayAdapter<std::vector<osg::Group*> > _leafParents;
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const GetObjectLocalCoords _getLocalCoords;
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const AddLeafObject _addLeafObject;
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const MakeLeaf _makeLeaf;
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};
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}
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#endif
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