source: trunk/VUT/OcclusionCullingSceneManager/include/OgreOcclusionCullingOctreeSceneTraverser.h @ 45

#ifndef _OcclusionCullingOctreeSceneTraverser_H__
#define _OcclusionCullingOctreeSceneTraverser_H__

#include "OgreOctree.h"
#include "OgreOcclusionCullingSceneTraverser.h"

using namespace std;

namespace Ogre {
        /**
                This class implements the compare operator for the priority queue
                especially for octree hierarchies using getCullBounds for bounding
                box computation. A lower distance has a higher value in the queue.
        */
        template <typename T> class octreeless 
        {
        public:
                octreeless(Camera *cam) { mCamera = cam; }
                
                bool operator() (T v1, T v2) const
                {
                        AxisAlignedBox box1, box2;
                        v1->_getCullBounds(&box1);
                        v2->_getCullBounds(&box2);

                        return getSquaredViewDepth(mCamera, &box1) > getSquaredViewDepth(mCamera, &box2);
                }

        private:
                Real getSquaredViewDepth(const Ogre::Camera* cam, const Ogre::AxisAlignedBox* box) const
                {
                        Vector3 mid  = ((box->getMinimum() - box->getMaximum()) * 0.5) + box->getMinimum();
                        return (cam->getDerivedPosition() - mid).squaredLength();                                                                   
                }

                Camera *mCamera;
                //AxisAlignedBox mBox1, mBox2;
                //Ogre::Vector3 min, max, mid, dist;
        };

        typedef pair<Octree *, HardwareOcclusionQuery *> OctreeQueryPair;
        typedef priority_queue<Octree *, vector<Octree *>, octreeless<vector<Octree *>::value_type> > OctreePriorityQueue;
        typedef queue<OctreeQueryPair> OctreeQueryQueue;

        class OcclusionCullingOctreeSceneTraverser: public OcclusionCullingSceneTraverser
        {
        public:
                OcclusionCullingOctreeSceneTraverser(SceneManager *sm, RenderSystem *rsys);
                ~OcclusionCullingOctreeSceneTraverser();
                //void renderScene( Camera *cam );
                void setSceneRoot(Octree *root);
                /** Sets the number of nodes in this octree 
                @remark do not confuse this with the OctreeNode class 
                which is derived from SceneNode
                @param num number of nodes in the octree
                */
                void setNumOctreeNodes( unsigned int num );
        
                /** Gets the given option for the scene traverser.
                @remarks
                    See setOption
                */
                bool getOption( const String &, void * );
                bool getOptionKeys( StringVector &refKeys );
                
        protected:
                /** Renders the scene with view frustum culling only. */
                void renderCullFrustum( Camera *cam );
                /** Renders the scene with the hierarchical stop and wait algorithm. */
                void renderStopAndWait( Camera *cam );
                /** Renders the scene with the coherent hierarchical algorithm and the query queye. */
                void renderCoherentWithQueue( Camera *cam );
                /** Issue a occlusion query for this node. */
                
                void initDistanceQueue(Camera *cam);
                void pullUpVisibility( Camera *cam, Octree *octree );
                void traverseOctant(Camera *cam, Octree *octant );
                void renderOctant( Camera *cam, Octree *octant );
                bool isLeaf(Octree *octant);

        private:
                OctreePriorityQueue *mOctreeDistanceQueue;
                // the octree root
                Octree *mOctreeSceneRoot;

                unsigned int mNumOctreeNodes;
        };

}
#endif // OcclusionCullingOctreeSceneTraverser_H