#ifndef _SamplingPreprocessor_H__
#define _SamplingPreprocessor_H__

#include <fstream>
using namespace std;

#include "Preprocessor.h"
#include "VssRay.h"

namespace GtpVisibilityPreprocessor {

class Exporter;

/** Sampling based visibility preprocessing. The implementation is based on heuristical
    sampling of view space */
class SamplingPreprocessor : public Preprocessor {
public:
		
  SamplingPreprocessor();
  ~SamplingPreprocessor();

  virtual bool ComputeVisibility();


protected:
	/** Sets up ray for sampling.
	*/
  void
  SetupRay(Ray &ray, 
		   const Vector3 &point, 
		   const Vector3 &direction,
		   const int type,
		   const Ray::Intersection &source);
  
  /** Refined sampling for finding "holes", i.e., difficult visibility.
   */
  void
  HoleSamplingPass();
  
  /** Casts a bundle of sample rays into the scene.
		@param sampleContributions the number of sample contributions
		@param contributingSamples the number of samples contributing
	*/
	void
	CastRays(const RayContainer &rays);
	
	/** Casts a single ray into the scene.
		@returns sample contributions
	*/
	int CastRay(Ray &ray);
	
	/** Verify if the exact visibility for this object was established.
	*/
	void
	VerifyVisibility(Intersectable *object);

	/** Sample the shiluette of objects in order to find visibility changes
		along the visibility skeleton.
	*/
	int 
	CastEdgeSamples(
					Intersectable *object,
					const Vector3 &point,
					MeshInstance *mi,
					const int samples
					);

	/** Processes the view cells during a pass.
		@param newRays the newly cast rays
		@param sampleContributions returns the accumulated contribution of the samples
		@param contributingSamples returns the samples contributing to pvs
	*/
	
	void ProcessViewCells(const RayContainer &newRays,
						  const ObjectContainer &objects,
						  int &sampleContributions,
						  int &contributingSamples);

	/**
		Returns random node as target for the current sample ray.
	*/
	KdNode *GetNodeToSample(Intersectable *object);


protected:


	int mPass;
	int mSamplesPerPass;
	int mTotalSamples;
	
	ofstream mStats;
	ObjectContainer mObjects;

	RayContainer mSampleRays;
	VssRayContainer mVssSampleRays;
};

}

#endif