awesome-attractor/kernels/UnravelHeart3D.hpp

#ifndef UNRAVELHEART3D_HPP
#define UNRAVELHEART3D_HPP

#include "../AttractorKernel.hpp"

#include <cmath>

class UnravelHeart3D : public AttractorKernel {
public:
	UnravelHeart3D():
		AttractorKernel(3, 8) {}

	virtual std::string type() const { return "unravel heart"; };

	virtual void operator()() {
		std::swap(vectorNew, vectorOld);

		vectorNew[0] = parameters[0]*(vectorOld[2] + parameters[1]);
		vectorNew[1] = parameters[2]*(vectorOld[0] + parameters[3]);
		vectorNew[2] = parameters[4]*(vectorOld[1] + parameters[5]);

		const double x = vectorNew[0];
		const double y = vectorNew[1];
		const double z = vectorNew[2];
		const double dist = x*x + y*y + 2.0*z*z - 1.0;//parameters[7];
		const double lh = dist*dist*dist;
		const double rh = parameters[6]*x*x*y*y*y;

		if(lh > rh) {
			const double sqrtDist = std::pow(std::abs(lh), 1.0/6.0);
			const double sqrtDist2 = std::pow(std::abs(rh), 1.0/6.0) * sign(parameters[6]);
			const double p = 1.0 - sqrtDist2 * (static_cast<int>(sqrtDist / sqrtDist2) + 1.0) / sqrtDist;
			vectorNew[0] *= p;
			vectorNew[1] *= -p;
			vectorNew[2] *= p;
		}
	}

	double sign(double x){
		return (x > 0) - (x < 0);
	}

};

#endif // UNRAVEL_HPP