source: GTP/trunk/App/Demos/Vis/FriendlyCulling/src/PvsCollectionRenderer.h @ 3284

#ifndef __PVSCOLLECTIONRENDERER_H
#define __PVSCOLLECTIONRENDERER_H

#include "RenderTraverser.h"

namespace CHCDemoEngine
{

struct ViewCell;

/** Preprocessing as well as online culling using hardware occlusion
    queries have certain pros and cons. This method allows 
        us to combine those two paradigms for the maximum performance. 
        In particular, we propose following
        algorithm, which gets rid of most of the shortcomings of either
        approach. I.e., it is a strictly conservative approach that requires
        only very short preprocessing time in the range of some seconds, while
        inducing practically no overhead during runtime.

        First we compute a very coarse global visibilitiy solution using our
        sampling based preprocessor, which will be already sufficient to drive the
        online alorithm. During walkthrough, we use occlusion queries to test
        potentially invisible objects in a very efficient way, eliminating most of
        the overhead of the query testing. The method assumes that previously
        invisible objects are not part of a PVS, and as long as the assumption
        hold's the algorithm has very low overhead. The method is conservative, and
        converges over time in the sense that newly found visible objects are added
        to the PVS. As the PVSs become more and more exact, the render time
        overhead reduces to a minimum.
*/
class PvsCollectionRenderer: public RenderTraverser
{
public:
        /** Default constructor.
        */
        PvsCollectionRenderer();
        
        virtual ~PvsCollectionRenderer();

        void SetViewCell(ViewCell *vc) { mViewCell = vc; }

        //virtual int GetType() const { return CULL_COLLECTOR; }
        virtual int GetType() const { return -1; }

protected:

        /** Traverses and renders the scene with the specified method
        */
        virtual void Traverse();

        void AddGeometryToPIS(BvhNode *node);


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

        ViewCell *mViewCell;
        /// the potentially invisible set of objects
        BvhNodeContainer mPIS;
};


}



#endif // RENDERTRAVERSER_H