minetest/src/noise.h

/*
Minetest-c55
Copyright (C) 2010-2011 celeron55, Perttu Ahola <celeron55@gmail.com>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#ifndef NOISE_HEADER
#define NOISE_HEADER

#include "debug.h"
#include "irr_v3d.h"

class PseudoRandom
{
public:
	PseudoRandom(): m_next(0)
	{
	}
	PseudoRandom(int seed): m_next(seed)
	{
	}
	void seed(int seed)
	{
		m_next = seed;
	}
	// Returns 0...32767
	int next()
	{
		m_next = m_next * 1103515245 + 12345;
		return((unsigned)(m_next/65536) % 32768);
	}
	int range(int min, int max)
	{
		if(max-min > 32768/10)
		{
			//dstream<<"WARNING: PseudoRandom::range: max > 32767"<<std::endl;
			assert(0);
		}
		if(min > max)
		{
			assert(0);
			return max;
		}
		return (next()%(max-min+1))+min;
	}
private:
	int m_next;
};

struct NoiseParams {
	float offset;
	float scale;
	v3f spread;
	int seed;
	int octaves;
	float persist;
};


// Convenience macros for getting/setting NoiseParams in Settings
#define getNoiseParams(x) getStruct<NoiseParams>((x), "f,f,v3,s32,s32,f")
#define setNoiseParams(x, y) setStruct((x), "f,f,v3,s32,s32,f", (y))

class Noise {
public:
	NoiseParams *np;
	int seed;
	int sx;
	int sy;
	int sz;
	float *noisebuf;
	float *buf;
	float *result;

	Noise(NoiseParams *np, int seed, int sx, int sy);
	Noise(NoiseParams *np, int seed, int sx, int sy, int sz);
	~Noise();

	void init(NoiseParams *np, int seed, int sx, int sy, int sz);
	void setSize(int sx, int sy);
	void setSize(int sx, int sy, int sz);
	void setSpreadFactor(v3f spread);
	void setOctaves(int octaves);
	void resizeNoiseBuf(bool is3d);

	void gradientMap2D(
		float x, float y,
		float step_x, float step_y,
		int seed);
	void gradientMap3D(
		float x, float y, float z,
		float step_x, float step_y, float step_z,
		int seed);
	float *perlinMap2D(float x, float y);
	float *perlinMap3D(float x, float y, float z);
	void transformNoiseMap();
};

// Return value: -1 ... 1
float noise2d(int x, int y, int seed);
float noise3d(int x, int y, int z, int seed);

float noise2d_gradient(float x, float y, int seed);
float noise3d_gradient(float x, float y, float z, int seed);

float noise2d_perlin(float x, float y, int seed,
		int octaves, float persistence);

float noise2d_perlin_abs(float x, float y, int seed,
		int octaves, float persistence);

float noise3d_perlin(float x, float y, float z, int seed,
		int octaves, float persistence);

float noise3d_perlin_abs(float x, float y, float z, int seed,
		int octaves, float persistence);

inline float easeCurve(float t) {
	return t * t * t * (t * (6.f * t - 15.f) + 10.f);
}

#define NoisePerlin2D(np, x, y, s) ((np)->offset + (np)->scale * \
		noise2d_perlin((float)(x) / (np)->spread.X, (float)(y) / (np)->spread.Y, \
		(s) + (np)->seed, (np)->octaves, (np)->persist))

#define NoisePerlin3D(np, x, y, z, s) ((np)->offset + (np)->scale * \
		noise2d_perlin((float)(x) / (np)->spread.X, (float)(y) / (np)->spread.Y, \
		(float)(z) / (np)->spread.Z, (s) + (np)->seed, (np)->octaves, (np)->persist))

#endif