spk_perlin.hpp

#pragma once
 
#include <array>
#include <functional>
#include <random>
#include <vector>
 
namespace spk
{
    class Perlin
    {
    public:
        enum class Interpolation
        {
            Linear,      
            SmoothStep 
        };
 
    private:
        std::array<int, 512> _values;
        Interpolation _interpolation;
        int _octaves = 3;
        float _persistence = 0.5f;
        float _lacunarity = 2.0f;
        float _frequency = 1.0f;
 
        static float _fade(float p_value, Interpolation p_interpolation);
        static float _lerp(float p_minValue, float p_maxValue, float p_value);
        static float _grad(int p_hash, float p_x);
        static float _grad(int p_hash, float p_x, float p_y);
        static float _grad(int p_hash, float p_x, float p_y, float p_z);
 
        void _reseed(unsigned int p_seed);
 
        float _noise1D(float p_x) const;
        float _noise2D(float p_x, float p_y) const;
        float _noise3D(float p_x, float p_y, float p_z) const;
 
        static float _fractal(
            const Perlin &p_perlin,
            std::function<float(const Perlin &, float, float, float)> p_noiseFunc,
            float p_x,
            float p_y,
            float p_z,
            int p_octaves,
            float p_persistence,
            float p_lacunarity,
            float p_frequency);
 
    public:
        Perlin(unsigned int p_seed = 0, Perlin::Interpolation p_interp = Perlin::Interpolation::SmoothStep);

        void setInterpolation(Interpolation p_interp);
        void setSeed(unsigned int p_seed);
        void setOctaves(int p_oct);
        void setPersistence(float p_p);
        void setLacunarity(float p_l);
        void setFrequency(float p_f);

        const int &octaves() const;
        const float &persistence() const;
        const float &lacunarity() const;
        const float &frequency() const;

        float sample1D(float p_x, float p_min = 0, float p_max = 1) const;
        float sample2D(float p_x, float p_y, float p_min = 0, float p_max = 1) const;
        float sample3D(float p_x, float p_y, float p_z, float p_min = 0, float p_max = 1) const;
    };
}