gistfile1.cs

Parallel.For(0, H, y =>
            {
                int j = y * 3 * W;
                //for(; y<ymax; ++y)
                {
                    for (int x = 0; x < W; ++x)
                    {
                        float a = max,
                              b = max,
                              c = max;
                        float t0, t1;
                        Vector2 xy = new Vector2(x, y);

                        for (int i = 0; i < N; ++i)
                        {
                            float distSq;
                            Vector2.DistanceSquared(ref xy, ref pts[i], out distSq);

                            if (distSq < c)
                            {
                                if (distSq < b)
                                {
                                    if (distSq < a)
                                    {
                                        // Xab
                                        t0 = a; t1 = b;
                                        a = distSq; b = t0; c = t1;
                                    }
                                    else
                                    {
                                        // aXb
                                        t0 = a; t1 = b;
                                        a = t0; b = distSq; c = t1;
                                    }
                                }
                                else
                                {
                                    //abX
                                    t0 = a; t1 = b;
                                    a = t0; b = t1; c = distSq;
                                }
                            }
                        }

                        data[j++] = a;
                        data[j++] = b;
                        data[j++] = c;
                    }
                }
            });