SimplexNoise.java

package com.minestellar.core.perlin;

import java.util.Random;

public class SimplexNoise {
	int[] perm = new int[512];
	public int[][] grad2d = new int[][] { { 0, 0 }, { 0, 1 }, { 1, 1 }, { 1, 0 } };

	public SimplexNoise(long seed) {
		final Random rand = new Random(seed);
		
		for (int i = 0; i < 256; i++) {
			this.perm[i] = i; // Fill up the random array with numbers 0-256
		}

		for (int i = 0; i < 256; i++) { // Shuffle those numbers for the random effect
			final int j = rand.nextInt(256);
			this.perm[i] = this.perm[i] ^ this.perm[j];
			this.perm[j] = this.perm[i] ^ this.perm[j];
			this.perm[i] = this.perm[i] ^ this.perm[j];
		}

		for (int i = 0; i < 256; i++) {
			this.perm[i + 256] = this.perm[i];
		}
	}
}