solid_noise.h

// solid_noise.h

#ifndef _SOLID_NOISE_H_
#define _SOLID_NOISE_H_ 1

#include <cstdlib>
#include "vector3.h"

class SolidNoise {
    public:
        SolidNoise();
        float noise(const Vector3&) const;
        float turbulence(const Vector3& p, int depth) const;
        float dturbulence(const Vector3& p, int depth, float d) const;
        float omega(float t) const;
        Vector3 gamma(int i, int j, int k) const;
        int intGamma(int i, int j) const;
        float knot(int i, int j, int k, Vector3& v) const;

        Vector3 grad[16];
        int phi[16];
};

inline float SolidNoise::omega(float t) const {
    t = (t > 0.0f) ? t : -t;
    // we can assume t is in [-1,1] in this code so no extra 'if' needed
    return (-6.0f*t*t*t*t*t + 15.0f*t*t*t*t - 10.0f*t*t*t + 1.0f);
}

inline Vector3 SolidNoise::gamma(int i, int j, int k) const {
    int idx;
    idx = phi[abs(k)%16];
    idx = phi[abs(j + idx) % 16];
    idx = phi[abs(i + idx) % 16];
    return grad[idx];
}

inline float SolidNoise::knot(int i, int j, int k, Vector3& v) const {
    return (omega(v.x())*omega(v.y())*omega(v.z()) * dot(gamma(i,j,k),v));
}

inline int SolidNoise::intGamma(int i, int j) const {
    int idx;
    idx = phi[abs(j%16)];
    idx = phi[abs(i + idx) % 16];
    return idx;
}

#endif // _SOLID_NOISE_H_