HeightmapGenerator.cs

using System;
using LibNoise;
using LibNoise.Builder;
using LibNoise.Filter;
using LibNoise.Modifier;
using LibNoise.Primitive;
using OpenTK;

namespace Erebus
{
    internal class HeightmapGenerator
    {
        private readonly int size;
        private readonly int seed;
        private readonly int octaves;
        private readonly float frequency;
        private readonly float lacunarity;
        private readonly NoiseQuality quality;
        private readonly ScaleBias scale;
        private readonly PrimitiveModule primitive;
        private readonly FilterModule filter;
        private NoiseMapBuilder projection;

        public HeightmapGenerator(int size)
        {
            this.size = size;
            seed = 0;
            octaves = 2;
            frequency = 0.01f;
            lacunarity = 2.0f;
            quality = NoiseQuality.Standard;

            primitive = new ImprovedPerlin();
            primitive.Quality = quality;
            primitive.Seed = seed;

            filter = new RidgedMultiFractal();
            filter.Frequency = frequency;
            filter.Lacunarity = lacunarity;
            filter.OctaveCount = octaves;
            filter.Primitive3D = (IModule3D)primitive;

            scale = new ScaleBias(filter, 1f, 0);
        }

        public HeightmapTile GenerateTile(int offsetX, int offsetY)
        {
            var noiseMap = new NoiseMap();

            projection = new NoiseMapBuilderPlane(offsetX * size, (offsetX * size) + size, offsetY * size, (offsetY * size) + size, true);
            projection.SetSize(size, size);
            projection.SourceModule = filter;
            projection.NoiseMap = noiseMap;
            projection.Build();

            var tileData = new double[size * size];

            for (int y = 0; y < size; y++)
            {
                for (int x = 0; x < size; x++)
                {
                    tileData[y * size + x] = projection.NoiseMap.GetValue(x, y);
                }
            }

            return new HeightmapTile(tileData, new Vector2(offsetX, offsetY));
        }
    }
}