source: trunk/VUT/OcclusionCullingSceneManager/include/OgreOcclusionCullingSceneManager.h @ 23

#ifndef _OcclusionCullingSceneManager_H__
#define _OcclusionCullingSceneManager_H__

#include "OgreSceneNode.h"
#include "OgreSceneManager.h"
#include "OgrePrerequisites.h"
#include <queue>

using namespace std;

namespace Ogre {
        /**
                This class implements the compare operator for the priority queue.
                a lower distance has a higher value in the queue
        */
        template <typename T> class myless
        {
        public:
                myless(Camera *cam) { mCamera = cam; }
                //bool operator() (HierarchyNode *v1, HierarchyNode *v2) const
                bool operator() (T v1, T v2) const
                {
                        return v1->getSquaredViewDepth(mCamera) > v2->getSquaredViewDepth(mCamera);
                }
        private:
                Camera *mCamera;
        };

        typedef priority_queue<SceneNode *, vector<SceneNode *>, myless<vector<SceneNode *>::value_type> > PriorityQueue;
        typedef queue<SceneNode *> QueryQueue;
        /**
                Class which implements a scene mangager which uses occlusion queries for culling occluded objects
        */
        class OcclusionCullingSceneManager : public SceneManager
        {
        public:
                enum {RENDER_CULL_FRUSTUM, RENDER_STOP_AND_WAIT, RENDER_COHERENT, NUM_RENDERMODES};
                
                OcclusionCullingSceneManager();
                ~OcclusionCullingSceneManager();
        
                /** Overriden from SceneManager. */
                void _renderVisibleObjects(void);
                void _findVisibleObjects(Camera* cam, bool onlyShadowCasters);
                void _updateSceneGraph(Camera* cam);

        protected:
                enum {MODE_QUERY, MODE_RENDER};

                int isLeaf(SceneNode *node);
                int countSceneNodes(SceneNode *node);
                void renderZPass();
                void traverseNode(SceneNode *node);
                /** Renders current node */
                void render(SceneNode *node);
                /** Sets rendering mode, e.g. query mode or render mode*/
                void setRenderingMode(int mode);
                
                /** Renders the scene with view frustum culling only. */
                void renderCullFrustum();
                /** Renders the scene with the hierarchical stop and wait algorithm. */
                void renderStopAndWait();
                /** Renders the scene with the coherent hierarchical algorithm and the query queye. */
                void renderCoherentWithQueue();
                /** Issue a occlusion query for this node. */
                void issueOcclusionQuery(SceneNode *node, bool wasVisible);
                /** Pulls up the visibility from the child nodes. */
                void pullUpVisibility(SceneNode *node);

                void deleteQueries();

                /** we use a priority queue rather than a renderstack */
                PriorityQueue *mDistanceQueue; 

                unsigned int mFrameId;
                unsigned int mVisibilityThreshold;
                unsigned int mNumSceneNodes;
                int mCurrentTestIdx;
                int mQueryMode;
                
                std::vector<HardwareOcclusionQuery *> mOcclusionQueries;
        };

}
#endif // OCCLUSIONCULLINGSCENEMANAGER_H