source: GTP/trunk/App/Demos/Vis/FriendlyCulling/src/CHCPlusPlusTraverser.h @ 2800

#ifndef __CHCPLUSPLUSTRAVERSER_H
#define __CHCPLUSPLUSTRAVERSER_H

#include "RenderTraverser.h"


namespace CHCDemoEngine
{

class OcclusionQuery;


/** Class predicting the visiblity of nodes.
*/
class VisibilityPredictor
{
public:
        /** Predicts the probability of a node to stay visible / invisible.
            The probability could be taken from a measured or analytic function.
        */
        float GetProbability(BvhNode *node) const 
        { 
                return 0.98f - 0.68f * exp(-(float)node->GetTimesTestedInvisible()); 
        }
};


/** Class implementing traversal using the CHC++ algorithm.
*/
class CHCPlusPlusTraverser: public RenderTraverser
{
public:
        
        CHCPlusPlusTraverser();

        virtual int GetType() const { return CHCPLUSPLUS;}


protected:
        /** Traverses and renders the scene with the specified method
        */
        virtual void Traverse();
        /** Queries nodes nodes tested invisible in previous frames.
        */
        void QueryPreviouslyInvisibleNodes(BvhNode *node);
        /** Computes the next multiquery.
        */
        OcclusionQuery *GetNextMultiQuery(BvhNodeContainer &iqueue);
        /** Issues batched multiqueries.
        */
        void IssueMultiQueries();
        /** Handles the result of an occlusion query.
        */
        void HandleQueryResult(OcclusionQuery *query);


        //////////////

        /// the query queue
        QueryQueue mQueryQueue;

        BvhNodeQueue mVQueue;
        BvhNodeContainer mIQueue;

        VisibilityPredictor mVisibilityPredictor;
};

}



#endif // __CHCPLUSPLUSTRAVERSER_H