G4Voxelizer.hh

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// G4Voxelizer
//
// Class description:
//
// Voxelizer for tessellated surfaces and solids positioning in 3D space,
// used in G4TessellatedSolid and G4MultiUnion.
 
// Author: Marek Gayer (CERN), 19.10.2012 - Created
// --------------------------------------------------------------------
#ifndef G4VOXELIZER_HH
#define G4VOXELIZER_HH
 
#include <vector>
#include <string>
#include <map>
 
#include "G4Transform3D.hh"
#include "G4RotationMatrix.hh"
#include "G4SurfBits.hh"
#include "G4Box.hh"
#include "G4VFacet.hh"
#include "G4VSolid.hh"
 
struct G4VoxelBox
{
  G4ThreeVector hlen; // half length of the box
  G4ThreeVector pos; // position of the box
};
 
struct G4VoxelInfo
{
  G4int count;
  G4int previous;
  G4int next;
};
 
/**
 * @brief G4Voxelizer is a tool for generating the optimisation structure
 * of tessellated surfaces and solids positioned in 3D space; it is used in
 * G4TessellatedSolid and G4MultiUnion.
 */
 
class G4Voxelizer
{
  public:
 
    /**
     * Constructor and default Destructor.
     */
    G4Voxelizer();
    ~G4Voxelizer() = default;
 
    /**
     * Builds the voxelisation structure for solids positioned in space.
     *  @param[in] solids The list of solids.
     *  @param[in] transforms The associated transformation in space.
     */
    void Voxelize(std::vector<G4VSolid*>& solids,
                  std::vector<G4Transform3D>& transforms);
 
    /**
     * Builds the voxelisation structure for facets forming a shape.
     *  @param[in] facets The list of facets.
     */
    void Voxelize(std::vector<G4VFacet*>& facets);
 
    /**
     * Displays the dX, dY, dZ, pX, pY and pZ for each node.
     */
    void DisplayVoxelLimits() const;
 
    /**
     * Prints the positions of the boundaries of the slices on the three axes.
     */
    void DisplayBoundaries();
 
    /**
     * Prints which solids are present in the slices previously elaborated.
     */
    void DisplayListNodes() const;
 
    /**
     * Displays the nodes located in a voxel characterised by its three indexes.
     */
    void GetCandidatesVoxel(std::vector<G4int>& voxels);
 
    /**
     * Methods returning in a vector container the nodes located in a voxel
     * characterised by its three indexes.
     *  @returns The total candidates number.
     */
    G4int GetCandidatesVoxelArray(const G4ThreeVector& point,
                                        std::vector<G4int>& list,
                                        G4SurfBits* crossed = nullptr) const;
    G4int GetCandidatesVoxelArray(const std::vector<G4int>& voxels,
                                  const G4SurfBits bitmasks[],
                                        std::vector<G4int>& list,
                                        G4SurfBits* crossed = nullptr) const;
    G4int GetCandidatesVoxelArray(const std::vector<G4int>& voxels,
                                        std::vector<G4int>& list,
                                        G4SurfBits* crossed = nullptr)const;
 
    /**
     * Returns the pointer to the array containing the characteristics
     * of each box.
     */
    inline const std::vector<G4VoxelBox>& GetBoxes() const;
 
    /**
     * Returns the boundary vector, given an 'index'.
     */
    inline const std::vector<G4double>& GetBoundary(G4int index) const;
 
    /**
     * Utility method for checking/updating current voxel given in input.
     */
    G4bool UpdateCurrentVoxel(const G4ThreeVector& point,
                              const G4ThreeVector& direction,
                                    std::vector<G4int>& curVoxel) const;
 
    /**
     * Updates current voxel based on provided 'point'.
     */
    inline void GetVoxel(std::vector<G4int>& curVoxel,
                         const G4ThreeVector& point) const;
 
    /**
     * Returns memory size of a slice.
     */
    inline G4int GetBitsPerSlice () const;
 
    /**
     * Returns true if 'point' is contained within boundaries.
     */
    G4bool Contains(const G4ThreeVector& point) const;
 
    /**
     * Returns the distance to next boundary, given 'point' and 'direction'
     * and updates current voxel 'curVoxel', using the index corresponding
     * to the closest voxel boundary on the ray.
     */
    G4double DistanceToNext(const G4ThreeVector& point,
                            const G4ThreeVector& direction,
                                  std::vector<G4int>& curVoxel) const;
 
    /**
     * Returns the distance to first bounding box, given 'point' and 'direction'.
     */
    G4double DistanceToFirst(const G4ThreeVector& point,
                             const G4ThreeVector& direction) const;
 
    /**
     * Returns the minimum distance of 'point' to the bounding box.
     */
    G4double DistanceToBoundingBox(const G4ThreeVector& point) const;
 
    /**
     * Utility for estimating the isotropic safety from a point 'p' outside
     * the current solid to any of its surfaces. The algorithm may be accurate
     * or should provide a fast underestimate, based on safety point 'f'.
     */
    G4double MinDistanceToBox (const G4ThreeVector& p,
                               const G4ThreeVector& f) const;
 
    /**
     * Accessors for voxels and points.
     */
    inline G4int GetVoxelsIndex(G4int x, G4int y, G4int z) const;
    inline G4int GetVoxelsIndex(const std::vector<G4int>& voxels) const;
    inline G4bool GetPointVoxel(const G4ThreeVector& p,
                                std::vector<G4int>& voxels) const;
    inline G4int GetPointIndex(const G4ThreeVector& p) const;
 
    /**
     * Returns the empty bits container.
     */
    inline const G4SurfBits& Empty() const;
 
    /**
     * Returns true if empty bit in container, given an 'index'.
     */
    inline G4bool IsEmpty(G4int index) const;
 
    /**
     * Setters/getter for the maximum number of voxels.
     */
    void SetMaxVoxels(G4int max);
    void SetMaxVoxels(const G4ThreeVector& reductionRatio);
    inline G4int GetMaxVoxels(G4ThreeVector& ratioOfReduction);
 
    /**
     * Logger returning the size of total allocated memory.
     */
    G4int AllocatedMemory();
 
    /**
     * Utility accessors/functions for voxels.
     */
    inline long long GetCountOfVoxels() const;
    inline long long CountVoxels(std::vector<G4double> boundaries[]) const;
    inline const std::vector<G4int>&
                 GetCandidates(std::vector<G4int>& curVoxel) const;
    inline G4int GetVoxelBoxesSize() const;
    inline const G4VoxelBox& GetVoxelBox(G4int i) const;
    inline const std::vector<G4int>& GetVoxelBoxCandidates(G4int i) const;
    inline G4int GetTotalCandidates() const;
    static void SetDefaultVoxelsCount(G4int count);
    static G4int GetDefaultVoxelsCount();
 
  private:
 
    /**
     * Binary search function for retrieving a value in a vector.
     */
    template <typename T> 
    inline G4int BinarySearch(const std::vector<T>& vec, T value) const;
 
    /**
     * Utilities.
     */
    G4String GetCandidatesAsString(const G4SurfBits& bits) const;
    void CreateSortedBoundary(std::vector<G4double>& boundaryRaw, G4int axis);
    void DisplayBoundaries(std::vector<G4double>& fBoundaries);
    void FindComponentsFastest(unsigned int mask,
                               std::vector<G4int>& list, G4int i) const;
    inline G4ThreeVector GetGlobalPoint(const G4Transform3D& trans,
                                        const G4ThreeVector& lpoint) const;
    void TransformLimits(G4ThreeVector& min, G4ThreeVector& max,
                         const G4Transform3D& transformation) const;
 
    /**
     * Build utilities.
     */
    void BuildEmpty ();
    void BuildBoundaries();
    void BuildReduceVoxels(std::vector<G4double> fBoundaries[],
                           G4ThreeVector reductionRatio);
    void BuildReduceVoxels2(std::vector<G4double> fBoundaries[],
                            G4ThreeVector reductionRatio);
    void BuildVoxelLimits(std::vector<G4VSolid*>& solids,
                          std::vector<G4Transform3D>& transforms);
    void BuildVoxelLimits(std::vector<G4VFacet*>& facets);
    void CreateMiniVoxels(std::vector<G4double> fBoundaries[],
                          G4SurfBits bitmasks[]);
    void BuildBitmasks(std::vector<G4double> fBoundaries[],
                       G4SurfBits bitmasks[], G4bool countsOnly = false);
    void BuildBoundingBox();
    void BuildBoundingBox(G4ThreeVector& amin, G4ThreeVector& amax,
                          G4double tolerance = 0.0);
    void SetReductionRatio(G4int maxVoxels, G4ThreeVector& reductionRatio);
 
 
  private:
 
   /**
    * @brief G4VoxelComparator is utility class used for comparing voxels.
    */
 
    class G4VoxelComparator
    {
      public:
 
      std::vector<G4VoxelInfo>& fVoxels;
 
      G4VoxelComparator(std::vector<G4VoxelInfo>& voxels) : fVoxels(voxels) {}
 
      G4bool operator()(const G4int& l, const G4int& r) const
      {
        G4VoxelInfo &lv = fVoxels[l], &rv = fVoxels[r];
        G4int left = lv.count +  fVoxels[lv.next].count;
        G4int right = rv.count + fVoxels[rv.next].count;
        return (left == right) ? l < r : left < right;
      }
    };
 
    static G4int fDefaultVoxelsCount;
 
    std::vector<G4VoxelBox> fVoxelBoxes;
    std::vector<std::vector<G4int> > fVoxelBoxesCandidates;
    mutable std::map<G4int, std::vector<G4int> > fCandidates;
 
    const std::vector<G4int> fNoCandidates;
 
    long long fCountOfVoxels;
 
    G4int fNPerSlice;
 
    std::vector<G4VoxelBox> fBoxes;
      // Array of box limits on the 3 cartesian axis
 
    std::vector<G4double> fBoundaries[3];
      // Sorted and if need skimmed fBoundaries along X,Y,Z axis
 
    std::vector<G4int> fCandidatesCounts[3]; 
 
    G4int fTotalCandidates;
 
    G4SurfBits fBitmasks[3];
 
    G4ThreeVector fBoundingBoxCenter;
 
    G4Box fBoundingBox;
 
    G4ThreeVector fBoundingBoxSize;
 
    G4ThreeVector fReductionRatio;
 
    G4int fMaxVoxels;
 
    G4double fTolerance;
 
    G4SurfBits fEmpty;
};
 
#include "G4Voxelizer.icc"
 
#endif