BlueNoise.h

// $Id: PDSampling.h,v 1.6 2006/07/06 23:13:18 zr Exp $

#include "RNG.h"
#include <cmath>
#include <vector>

#define kMaxPointsPerCell 9

class RangeList;
class ScallopedRegion;

class Vec2 {
public:
        Vec2() {};
        Vec2(float _x, float _y) : x(_x), y(_y) {};

        float x,y;

        float length() { return sqrt(x*x + y*y); }

        bool operator ==(const Vec2 &b) const { return x==b.x && y==b.y; }
        Vec2 operator +(Vec2 b) { return Vec2(x+b.x, y+b.y); }
        Vec2 operator -(Vec2 b) { return Vec2(x-b.x, y-b.y); }
        Vec2 operator *(Vec2 b) { return Vec2(x*b.x, y*b.y); }
        Vec2 operator /(Vec2 b) { return Vec2(x/b.x, y*b.y); }

        Vec2 operator +(float n) { return Vec2(x+n, y+n); }
        Vec2 operator -(float n) { return Vec2(x-n, y-n); }
        Vec2 operator *(float n) { return Vec2(x*n, y*n); }
        Vec2 operator /(float n) { return Vec2(x/n, y*n); }

        Vec2 &operator +=(Vec2 b) { x+=b.x; y+=b.y; return *this; }
        Vec2 &operator -=(Vec2 b) { x-=b.x; y-=b.y; return *this; }
        Vec2 &operator *=(Vec2 b) { x*=b.x; y*=b.y; return *this; }
        Vec2 &operator /=(Vec2 b) { x/=b.x; y/=b.y; return *this; }

        Vec2 &operator +=(float n) { x+=n; y+=n; return *this; }
        Vec2 &operator -=(float n) { x-=n; y-=n; return *this; }
        Vec2 &operator *=(float n) { x*=n; y*=n; return *this; }
        Vec2 &operator /=(float n) { x/=n; y/=n; return *this; }
};

class BlueNoise {
protected:
        RNG m_rng;
        std::vector<int> m_neighbors;
        
        int (*m_grid)[kMaxPointsPerCell];
        int m_gridSize;
        float m_gridCellSize;
        
public:
        std::vector<Vec2> points;
        float radius;
        bool isTiled;

public:
        BlueNoise(float radius, bool isTiled=true, bool usesGrid=true);
        virtual ~BlueNoise() { };

        //

        bool pointInDomain(Vec2 &a);

                // return shortest distance between _a_ 
                // and _b_ (accounting for tiling)
        float getDistanceSquared(Vec2 &a, Vec2 &b) { Vec2 v = getTiled(b-a); return v.x*v.x + v.y*v.y; }
        float getDistance(Vec2 &a, Vec2 &b) { return sqrt(getDistanceSquared(a, b)); }

                // generate a random point in square
        Vec2 randomPoint();

                // return tiled coordinates of _v_
        Vec2 getTiled(Vec2 v);

                // return grid x,y for point
        void getGridXY(Vec2 &v, int *gx_out, int *gy_out);

                // add _pt_ to point list and grid
        void addPoint(Vec2 pt);

                // populate m_neighbors with list of
                // all points within _radius_ of _pt_
                // and return number of such points
        int findNeighbors(Vec2 &pt, float radius);

                // return distance to closest neighbor within _radius_
        float findClosestNeighbor(Vec2 &pt, float radius);

                // find available angle ranges on boundary for candidate 
                // by subtracting occluded neighbor ranges from _rl_
        void findNeighborRanges(int index, RangeList &rl);

                // extend point set by boundary sampling until domain is 
                // full
        void maximize();

                // apply one step of Lloyd relaxation
        void relax();

        //

        void complete();

  void writeToBool(bool* noise, int size);
};

---