source: GTP/trunk/Lib/Vis/Preprocessing/src/SamplingStrategy.h @ 1983

#ifndef _SamplingStategy_H__
#define _SamplingStategy_H__

#include <vector>
using namespace std;

#include "common.h"
#include "Halton.h"
namespace GtpVisibilityPreprocessor {

class Vector2;
class Vector3;
class VssRay;
class Preprocessor;
struct SimpleRay;
class SimpleRayContainer;

struct VssRayContainer;

/** This class generates a specific sampling strategy.
*/
class SamplingStrategy
{
public:

        /** Sample rays of particular type
        */
        enum 
        {
                DUMMY_DISTRIBUTION = 0,
                DIRECTION_BASED_DISTRIBUTION,
                OBJECT_BASED_DISTRIBUTION,
                DIRECTION_BOX_BASED_DISTRIBUTION,
                SPATIAL_BOX_BASED_DISTRIBUTION,
                VSS_BASED_DISTRIBUTION,
                RSS_BASED_DISTRIBUTION,
                RSS_SILHOUETTE_BASED_DISTRIBUTION,
                OBJECT_DIRECTION_BASED_DISTRIBUTION,
                OBJECTS_INTERIOR_DISTRIBUTION,
                REVERSE_OBJECT_BASED_DISTRIBUTION,
                VIEWCELL_BORDER_BASED_DISTRIBUTION,
                VIEWSPACE_BORDER_BASED_DISTRIBUTION,
                REVERSE_VIEWSPACE_BORDER_BASED_DISTRIBUTION,
                GLOBAL_LINES_DISTRIBUTION,
                GVS,
                MUTATION_BASED_DISTRIBUTION,
                HW_GLOBAL_LINES_DISTRIBUTION
        };

        /** Default constructor
        */
        SamplingStrategy(Preprocessor &preprocessor);

        virtual ~SamplingStrategy();

        /** Each strategy has to implement this function.
        @returns true if generated valid sample.
        */

        virtual int GenerateSamples(const int number, SimpleRayContainer &rays);

        virtual bool GenerateSample(SimpleRay &ray) = 0;

        // true if the strategy keeps pointers to rays and thus they should get deleted
        // outside, in that case the strategy has to use reference counting and deleting the rays
        // by itself if the number of references drops to zero
        virtual bool RequiresRays() { return false; }


        virtual void Update(VssRayContainer &vssRays) {}

        friend bool LowerRatio(const SamplingStrategy *a, const SamplingStrategy *b) {
                return a->mRatio < b->mRatio;
        }

public:

  /// variables usefull for mixed distribution sampling
  int mType;
  int mRays;
  float mContribution;
  
  int mTotalRays;
  int mGeneratedRays;
  float mTotalContribution;
  
  float mTime;
  float mRatio;

protected:

        //static HaltonSequence sHalton;
        Preprocessor &mPreprocessor;
};


class ObjectBasedDistribution: public SamplingStrategy
{
 public:
 
  
  ObjectBasedDistribution(Preprocessor &preprocessor):
        SamplingStrategy(preprocessor) {
        mType = OBJECT_BASED_DISTRIBUTION;
  }

private:
  
        virtual bool GenerateSample(SimpleRay &ray);
    static HaltonSequence sHalton;
};


class ReverseObjectBasedDistribution: public SamplingStrategy
{
 public:
        
         ReverseObjectBasedDistribution(Preprocessor &preprocessor):
           SamplingStrategy(preprocessor) {
           mType = REVERSE_OBJECT_BASED_DISTRIBUTION;
         }

private:
        
        virtual bool GenerateSample(SimpleRay &ray);
};


class ObjectDirectionBasedDistribution: public SamplingStrategy
{
  
public:
         ObjectDirectionBasedDistribution(Preprocessor &preprocessor):
         SamplingStrategy(preprocessor) {
           mType = OBJECT_DIRECTION_BASED_DISTRIBUTION;
         }

private:

        static HaltonSequence sHalton;
        virtual bool GenerateSample(SimpleRay &ray);
};


class DirectionBasedDistribution: public SamplingStrategy
{
 public:
  DirectionBasedDistribution(Preprocessor &preprocessor):
        SamplingStrategy(preprocessor){
        mType = DIRECTION_BASED_DISTRIBUTION;
  }
private:
  virtual bool GenerateSample(SimpleRay &ray);
  static HaltonSequence sHalton;
};


class DirectionBoxBasedDistribution: public SamplingStrategy
{
 public:
         DirectionBoxBasedDistribution(Preprocessor &preprocessor):
           SamplingStrategy(preprocessor){
           mType = DIRECTION_BOX_BASED_DISTRIBUTION;
         }
           
private:
           virtual bool GenerateSample(SimpleRay &ray);
};


class SpatialBoxBasedDistribution: public SamplingStrategy
{
 public:
         
         SpatialBoxBasedDistribution(Preprocessor &preprocessor):
        SamplingStrategy(preprocessor){
        mType = SPATIAL_BOX_BASED_DISTRIBUTION;
  }
  
private:
        
        virtual bool GenerateSample(SimpleRay &ray);
        static HaltonSequence sHalton;
};


class ViewSpaceBorderBasedDistribution: public SamplingStrategy
{
 public:
         ViewSpaceBorderBasedDistribution(Preprocessor &preprocessor):
           SamplingStrategy(preprocessor){
           mType = VIEWSPACE_BORDER_BASED_DISTRIBUTION;
         }
         
private:

         virtual bool GenerateSample(SimpleRay &ray);
};


class ReverseViewSpaceBorderBasedDistribution: public SamplingStrategy
{
 public:
         ReverseViewSpaceBorderBasedDistribution(Preprocessor &preprocessor):
           SamplingStrategy(preprocessor){
           mType = REVERSE_VIEWSPACE_BORDER_BASED_DISTRIBUTION;
         }
         
private:
         virtual bool GenerateSample(SimpleRay &ray);
};


class ViewCellBorderBasedDistribution: public SamplingStrategy
{
 public:
  ViewCellBorderBasedDistribution(Preprocessor &preprocessor):
        SamplingStrategy(preprocessor) {
        mType = VIEWCELL_BORDER_BASED_DISTRIBUTION;

  }

private:
  virtual bool GenerateSample(SimpleRay &ray);
};

class MutationBasedDistribution: public SamplingStrategy
{
public:
  MutationBasedDistribution(Preprocessor &preprocessor);
  virtual void Update(VssRayContainer &vssRays);

  virtual bool RequiresRays() { return true; }

private:
  virtual bool GenerateSample(SimpleRay &ray);

  struct RayEntry {
        // halton sequence for generatin gmutations of this ray
        VssRay *mRay;
        int mSamples;
        HaltonSequence mHalton;
        float mImportance;
        float mCdf;

        float GetSamplingFactor() const { return mSamples/mImportance; }
        RayEntry() {}
        RayEntry(VssRay *r):mRay(r), mSamples(0), mHalton(), mImportance(1.0f) {}
  };


  Vector3
  ComputeOriginMutation(const VssRay &ray,
                                                const Vector3 &U,
                                                const Vector3 &V,
                                                const Vector2 vr2,
                                                const float radius
                                                );

  Vector3
  ComputeTerminationMutation(const VssRay &ray,
                                                         const Vector3 &U,
                                                         const Vector3 &V,
                                                         const Vector2 vr2,
                                                         const float radius
                                                         );

  RayEntry &GetEntry(const int index) {
        return mRays[(mBufferStart+index)%mRays.size()];
  }
  
  vector<RayEntry> mRays;
  int mMaxRays;
  float mOriginMutationSize;
  int mBufferStart;
  int mLastIndex;
};

class GlobalLinesDistribution: public SamplingStrategy
{
public:
 
  GlobalLinesDistribution(Preprocessor &preprocessor):
        SamplingStrategy(preprocessor) {
        mType = GLOBAL_LINES_DISTRIBUTION;
  }
  
private:

        virtual bool GenerateSample(SimpleRay &ray);
        static HaltonSequence sHalton;
};


class HwGlobalLinesDistribution: public SamplingStrategy
{
public:
 
  HwGlobalLinesDistribution(Preprocessor &preprocessor):
        SamplingStrategy(preprocessor) {
        //mType = HW_GLOBAL_LINES_DISTRIBUTION;
  }
  
private:

        virtual bool GenerateSample(SimpleRay &ray);
        static HaltonSequence sHalton;
};

/** This strategy generates samples inside of the objects, e.g.,
        for sampling the inside of a colon.
*/
/*class ObjectsInteriorDistribution: public SamplingStrategy
{
 public:
         ObjectsInteriorDistribution(Preprocessor &preprocessor):
         SamplingStrategy(preprocessor) {}
         
         virtual bool GenerateSample(SimpleRay &ray);
};
*/

class MixtureDistribution: public SamplingStrategy 
{
public:
   
  // container for the distributions
  vector<SamplingStrategy *> mDistributions;
  
  MixtureDistribution(Preprocessor &preprocessor):
        SamplingStrategy(preprocessor)
  {
  }

  // has to called before first usage
  void Init();

  // equalize distribution contributions
  void
  Reset();
  
  // add contributions of the sample to the strategies
  void ComputeContributions(VssRayContainer &vssRays);

  // update distributions with new rays
  // warning: some rays can get deleted (if maintained internally by the
  // particular distribution)!
  void UpdateDistributions(VssRayContainer &vssRays);

  void
  UpdateRatios();

  // construct distribution mixture from a string describing the required distributions
  bool
  Construct(char *str);

  virtual bool RequiresRays() {
        for (int i=0; i < (int)mDistributions.size(); i++)
          if (mDistributions[i]->RequiresRays())
                return true;
        return false;
  }
  
  virtual int GenerateSamples(const int number, SimpleRayContainer &rays);
  
private:

        // Generate a new sample according to a mixture distribution
        virtual bool GenerateSample(SimpleRay &ray);

        // halton sequence generator for deciding between distributions
        static HaltonSequence sHalton;
};

};

#endif