#include<stdlib.h>
#include<stdio.h>
#include<math.h>
#include<iostream>

using namespace std;

int permutation[] = { 151, 160, 137, 91, 90, 15, 131, 13, 201, 95, 96, 53, 194, 233, 7, 225,
	140, 36, 103, 30, 69, 142, 8, 99, 37, 240, 21, 10, 23, 190, 6, 148,
	247, 120, 234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11, 32,
	57, 177, 33, 88, 237, 149, 56, 87, 174, 20, 125, 136, 171, 168, 68, 175,
	74, 165, 71, 134, 139, 48, 27, 166, 77, 146, 158, 231, 83, 111, 229, 122,
	60, 211, 133, 230, 220, 105, 92, 41, 55, 46, 245, 40, 244, 102, 143, 54,
	65, 25, 63, 161, 1, 216, 80, 73, 209, 76, 132, 187, 208, 89, 18, 169,
	200, 196, 135, 130, 116, 188, 159, 86, 164, 100, 109, 198, 173, 186, 3, 64,
	52, 217, 226, 250, 124, 123, 5, 202, 38, 147, 118, 126, 255, 82, 85, 212,
	207, 206, 59, 227, 47, 16, 58, 17, 182, 189, 28, 42, 223, 183, 170, 213,
	119, 248, 152, 2, 44, 154, 163, 70, 221, 153, 101, 155, 167, 43, 172, 9,
	129, 22, 39, 253, 19, 98, 108, 110, 79, 113, 224, 232, 178, 185, 112, 104,
	218, 246, 97, 228, 251, 34, 242, 193, 238, 210, 144, 12, 191, 179, 162, 241,
	81, 51, 145, 235, 249, 14, 239, 107, 49, 192, 214, 31, 181, 199, 106, 157,
	184, 84, 204, 176, 115, 121, 50, 45, 127, 4, 150, 254, 138, 236, 205, 93,
	222, 114, 67, 29, 24, 72, 243, 141, 128, 195, 78, 66, 215, 61, 156, 180 };

int p[512];

double fade(double t) { return t * t * t * (t * (t * 6 - 15) + 10); }
double lerp(double t, double a, double b) { return a + t * (b - a); }
double grad(int hash, double x, double y, double z) {
	int h = hash & 15;
	double u = h < 8 ? x : y,
		v = h < 4 ? y : h == 12 || h == 14 ? x : z;
	return ((h & 1) == 0 ? u : -u) + ((h & 2) == 0 ? v : -v);
}

double noise(double x, double y, double z) {
	int X = (int)floor(x) & 255,
		Y = (int)floor(y) & 255,
		Z = (int)floor(z) & 255;
	x -= floor(x);
	y -= floor(y);
	z -= floor(z);
	double u = fade(x),
		v = fade(y),
		w = fade(z);
	int A = p[X] + Y, AA = p[A] + Z, AB = p[A + 1] + Z,
		B = p[X + 1] + Y, BA = p[B] + Z, BB = p[B + 1] + Z;

	return lerp(w, lerp(v, lerp(u, grad(p[AA], x, y, z),
		grad(p[BA], x - 1, y, z)),
		lerp(u, grad(p[AB], x, y - 1, z),
			grad(p[BB], x - 1, y - 1, z))),
		lerp(v, lerp(u, grad(p[AA + 1], x, y, z - 1),
			grad(p[BA + 1], x - 1, y, z - 1)),
			lerp(u, grad(p[AB + 1], x, y - 1, z - 1),
				grad(p[BB + 1], x - 1, y - 1, z - 1))));
}

void loadPermutation() {
	for (int i = 0; i < 256; i++) {
		p[256 + i] = p[i] = permutation[i];
	}
}


double OctavePerlin(double x, double y, double z, int octaves, double persistence) {
	double total = 0;
	double frequency = 1;
	double amplitude = 1;
	for (int i = 0; i < octaves; i++) {
		total += noise(x * frequency, y * frequency, z * frequency) * amplitude;

		amplitude *= persistence;
		frequency *= 2;
	}

	return total;
}

int main1()
{
	loadPermutation();
	cout.precision(17);
	cout << noise(3.14, 42.0, 7.0) << endl;
	cout << OctavePerlin(3.14, 42.0, 7.0,3,2) << endl;
	return 0;
}