/*--------------------------------------------------------------------
 Simplex Noise C++ implementation
 Based on a public domain code by Stefan Gustavson.
 (The original header is below)
--------------------------------------------------------------------*/
/*-- start of the original header --*/
/*
* A speed-improved simplex noise algorithm for 2D, 3D and 4D in Java.
*
* Based on example code by Stefan Gustavson (stegu@itn.liu.se).
* Optimisations by Peter Eastman (peastman@drizzle.stanford.edu).
* Better rank ordering method by Stefan Gustavson in 2012.
*
* This could be speeded up even further, but it's useful as it is.
*
* Version 2012-03-09
*
* This code was placed in the public domain by its original author,
* Stefan Gustavson. You may use it as you see fit, but
* attribution is appreciated.
*
*/
/*-- end of the original header --*/

#ifndef IWA_SIMPLEXNOISE_H
#define IWA_SIMPLEXNOISE_H

struct Grad {
	int x, y, z, w;
	Grad(int x_, int y_, int z_)
		: x(x_), y(y_), z(z_), w(0) {}
	Grad(int x_, int y_, int z_, int w_)
		: x(x_), y(y_), z(z_), w(w_) {}
};

struct CellIds {
	int i, j, k;
	int i1, j1, k1;
	int i2, j2, k2;
	CellIds(int _i = 0, int _j = 0, int _k = 0,
			int _i1 = 0, int _j1 = 0, int _k1 = 0,
			int _i2 = 0, int _j2 = 0, int _k2 = 0)
	{
		i = _i;
		j = _j;
		k = _k;
		i1 = _i1;
		j1 = _j1;
		k1 = _k1;
		i2 = _i2;
		j2 = _j2;
		k2 = _k2;
	}

	bool operator==(const CellIds &right) const
	{
		return i == right.i &&
			   j == right.j &&
			   k == right.k &&
			   i1 == right.i1 &&
			   j1 == right.j1 &&
			   k1 == right.k1 &&
			   i2 == right.i2 &&
			   j2 == right.j2 &&
			   k2 == right.k2;
	}
};

class SimplexNoise
{
	// This method is a *lot* faster than using (int)Math.floor(x)
	static int fastfloor(double x)
	{
		int xi = (int)x;
		return x < xi ? xi - 1 : xi;
	}

	static double dot(Grad g, double x, double y)
	{
		return g.x * x + g.y * y;
	}

	static double dot(Grad g, double x, double y, double z)
	{
		return g.x * x + g.y * y + g.z * z;
	}

	static double dot(Grad g, double x, double y, double z, double w)
	{
		return g.x * x + g.y * y + g.z * z + g.w * w;
	}

public:
	SimplexNoise();
	// 2D simplex noise
	static double noise(double xin, double yin);
	// 3D simplex noise
	static double noise(double xin, double yin, double zin);
	// 4D simplex noise
	static double noise(double x, double y, double z, double w);

	/*- セルまたぎを防ぐために、現在の所属セルを得る -*/
	static CellIds getCellIds(double xin, double yin, double zin);
};

#endif