#include "Mesh.h"
#include "FilterBasedDistribution.h"
#include "Vector3.h"
#include "Preprocessor.h"
#include "ViewCellsManager.h"

namespace GtpVisibilityPreprocessor {

bool
FilterBasedDistribution::GenerateSample(SimpleRay &ray)
{
  int tries = 0;
  const int maxTries = 10;
  
  while (mViewCell == NULL || samplesGenerated >= samplesToGenerate
		 ) {
	// find a new viewcell to cast the sample from
	if (tries++ > maxTries)
	  return false;

	Vector3 point; 

	
	float r[3];
	r[0] = RandomValue(0.0f,1.0f);
	r[1] = RandomValue(0.0f,1.0f);
	r[2] = RandomValue(0.0f,1.0f);
	//	static HaltonSequence sHalton;
	//	sHalton.GetNext(3, r);
	
	mPreprocessor.mViewCellsManager->GetViewPoint(point, Vector3(r[0],
																 r[1],
																 r[2]));

	
	mViewCell = mPreprocessor.mViewCellsManager->GetViewCell(point);
	
	if (mViewCell && mViewCell->GetPvs().GetSize()) {

	  //	  cout<<mViewCell<<endl;

	  
	  
	  // apply spatial filter
	  mFilteredPvs.Clear();
	  PvsFilterStatistics fstat = mPreprocessor.mViewCellsManager->
		ApplyFilter2(mViewCell,
					 false,
					 mPreprocessor.mViewCellsManager->GetFilterWidth(),
					 mFilteredPvs,
					 NULL,
					 true);
	  
	  //	  cout<<mViewCell->GetPvs().GetSize()<<" "<<mFilteredPvs.GetSize()<<endl;

	  if (mFilteredPvs.GetSize()) {
		samplesGenerated = 0;
		samplesToGenerate = Max(100, Min(1000, mFilteredPvs.GetSize()));
	  } else
		mViewCell = NULL; // try another viewcell
	}
  }

  Vector3 origin, normal;
  
  mViewCell->GetRandomSurfacePoint(origin, normal);
  
  // pickup random object from the filtered pvs
  int id = (int)RandomValue(0, (Real)((float)mFilteredPvs.GetSize() - 0.5f));
  
  ObjectPvsIterator pit = mFilteredPvs.GetIterator();

  Intersectable *object;
  
  for (; id>=0; --id)
	object = pit.Next();

  
  Vector3 point;
  object->GetRandomSurfacePoint(point, normal);
  Vector3 direction = point - origin;

  const float c = Magnitude(direction);
  
  if (c <= Limits::Small) 
	return false;
  
  direction *= 1.0f / c;

  // $$ jb the pdf is yet not correct for all sampling methods!
  const float pdf = 1.0f;
  
  ray = SimpleRay(origin, direction, FILTER_BASED_DISTRIBUTION, pdf);
  
  //cout << "ray: " << ray.mOrigin << " " << ray.mDirection << endl;
  
  samplesGenerated++;
  
  return true;
}

}