/**
 * Perlin Noise implementation for the ground (header file)
 **/
#pragma once
#include "Implicit.hpp"
#include <cmath>
#include <random>
#include <vector>
#include <algorithm>

class PerlinNoise : public ImplicitSurface {
    std::vector<int> p;
    public:
        PerlinNoise();
        PerlinNoise(unsigned int seed);
        double operator() (double _x, double _y, double _z) const;
        double noise(double x, double y) const;
        Point normal_vector(double x, double y);
        double fBm(double x, double y, double z, int octaves, double
                lacunarity, double gain) const;

        virtual Point location_hint() const;
        Point location_hint(double x, double z) const;
    private:
        double noise(double x, double y, double z) const;
        double fade(double t) const;
        double lerp(double t, double a, double b) const;
        double grad(int hash, double x, double y, double z) const;
};