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using System;
using System.Collections.Generic;
using System.Text;

namespace libTerrain
{
    partial class Channel
    {
        enum NeighbourSystem
        {
            Moore,
            VonNeumann
        };

        private int[] Neighbours(NeighbourSystem type, int index)
        {
            int[] coord = new int[2];

            index++;

            switch (type)
            {
                case NeighbourSystem.Moore:
                    switch (index)
                    {
                        case 1:
                            coord[0] = -1;
                            coord[1] = -1;
                            break;

                        case 2:
                            coord[0] = -0;
                            coord[1] = -1;
                            break;

                        case 3:
                            coord[0] = +1;
                            coord[1] = -1;
                            break;

                        case 4:
                            coord[0] = -1;
                            coord[1] = -0;
                            break;

                        case 5:
                            coord[0] = -0;
                            coord[1] = -0;
                            break;

                        case 6:
                            coord[0] = +1;
                            coord[1] = -0;
                            break;

                        case 7:
                            coord[0] = -1;
                            coord[1] = +1;
                            break;

                        case 8:
                            coord[0] = -0;
                            coord[1] = +1;
                            break;

                        case 9:
                            coord[0] = +1;
                            coord[1] = +1;
                            break;

                        default:
                            break;
                    }
                    break;

                case NeighbourSystem.VonNeumann:
                    switch (index)
                    {
                        case 1:
                            coord[0] = 0;
                            coord[1] = -1;
                            break;

                        case 2:
                            coord[0] = -1;
                            coord[1] = 0;
                            break;

                        case 3:
                            coord[0] = +1;
                            coord[1] = 0;
                            break;

                        case 4:
                            coord[0] = 0;
                            coord[1] = +1;
                            break;

                        case 5:
                            coord[0] = -0;
                            coord[1] = -0;
                            break;

                        default:
                            break;
                    }
                    break;
            }

            return coord;
        }
    }
}