iamabigartist_OurForests/OF test0/Assets/Projects/VolumeTerra/Scripts/Generate/Terrain/Noise/SimplexNoiseGenerator.cs
using UnityEngine;
namespace VolumeTerra.Generate.Terrain.Noise
{
	public class SimplexNoiseGenerator {
		private int[] A = new int[3];
		private float s, u, v, w;
		private int i, j, k;
		private float onethird = 0.333333333f;
		private float onesixth = 0.166666667f;
		private int[] T;
	
		public SimplexNoiseGenerator() {
			if (T == null) {
				System.Random rand = new System.Random();
				T = new int[8];
				for (int q = 0; q < 8; q++)
					T[q] = rand.Next();
			}
		}
	
		public SimplexNoiseGenerator(string seed) {
			T = new int[8];
			string[] seed_parts = seed.Split(new char[] {' '});
		
			for(int q = 0; q < 8; q++) {
				int b;
				try {
					b = int.Parse(seed_parts[q]);
				} catch {
					b = 0x0;
				}
				T[q] = b;
			}
		}
	
		public SimplexNoiseGenerator(int[] seed) { // {0x16, 0x38, 0x32, 0x2c, 0x0d, 0x13, 0x07, 0x2a}
			T = seed;
		}
	
		public string GetSeed() {
			string seed = "";
		
			for(int q=0; q < 8; q++) {
				seed += T[q].ToString();
				if(q < 7)
					seed += " ";
			}
		
			return seed;
		}
	
		public float coherentNoise(float x, float y, float z, int octaves=1, int multiplier = 25, float amplitude = 0.5f, float lacunarity = 2, float persistence = 0.9f) {
			Vector3 v3 = new Vector3(x,y,z)/multiplier;
			float val = 0;
			for (int n = 0; n < octaves; n++) {
				val += noise(v3.x,v3.y,v3.z) * amplitude;
				v3 *= lacunarity;
				amplitude *= persistence;
			}
			return val;
		}
	
		public int getDensity(Vector3 loc) {
			float val = coherentNoise(loc.x, loc.y, loc.z);
			return (int)Mathf.Lerp(0,255,val);
		}
    
		// Simplex Noise Generator
		public float noise(float x, float y, float z) {
			s = (x + y + z) * onethird;
			i = fastfloor(x + s);
			j = fastfloor(y + s);
			k = fastfloor(z + s);

			s = (i + j + k) * onesixth;
			u = x - i + s;
			v = y - j + s;
			w = z - k + s;

			A[0] = 0; A[1] = 0; A[2] = 0;

			int hi = u >= w ? u >= v ? 0 : 1 : v >= w ? 1 : 2;
			int lo = u < w ? u < v ? 0 : 1 : v < w ? 1 : 2;

			return kay(hi) + kay(3 - hi - lo) + kay(lo) + kay(0);
		}

		float kay(int a) {
			s = (A[0] + A[1] + A[2]) * onesixth;
			float x = u - A[0] + s;
			float y = v - A[1] + s;
			float z = w - A[2] + s;
			float t = 0.6f - x * x - y * y - z * z;
			int h = shuffle(i + A[0], j + A[1], k + A[2]);
			A[a]++;
			if (t < 0) return 0;
			int b5 = h >> 5 & 1;
			int b4 = h >> 4 & 1;
			int b3 = h >> 3 & 1;
			int b2 = h >> 2 & 1;
			int b1 = h & 3;

			float p = b1 == 1 ? x : b1 == 2 ? y : z;
			float q = b1 == 1 ? y : b1 == 2 ? z : x;
			float r = b1 == 1 ? z : b1 == 2 ? x : y;

			p = b5 == b3 ? -p : p;
			q = b5 == b4 ? -q : q;
			r = b5 != (b4 ^ b3) ? -r : r;
			t *= t;
			return 8 * t * t * (p + (b1 == 0 ? q + r : b2 == 0 ? q : r));
		}

		int shuffle(int i, int j, int k) {
			return b(i, j, k, 0) + b(j, k, i, 1) + b(k, i, j, 2) + b(i, j, k, 3) + b(j, k, i, 4) + b(k, i, j, 5) + b(i, j, k, 6) + b(j, k, i, 7);
		}

		int b(int i, int j, int k, int B) {
			return T[b(i, B) << 2 | b(j, B) << 1 | b(k, B)];
		}

		int b(int N, int B) {
			return N >> B & 1;
		}
    
		int fastfloor(float n) {
			return n > 0 ? (int)n : (int)n - 1;
		}
	}
}