#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