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/*
* Perlin noise generator
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Perlin Noise generator
*/
#ifndef AVFILTER_PERLIN_H
#define AVFILTER_PERLIN_H
#include <stdint.h>
enum FFPerlinRandomMode {
FF_PERLIN_RANDOM_MODE_RANDOM,
FF_PERLIN_RANDOM_MODE_KEN,
FF_PERLIN_RANDOM_MODE_SEED,
FF_PERLIN_RANDOM_MODE_NB
};
/**
* Perlin generator context. This needs to be initialized with the
* parameters used to generate the Perlin noise.
*/
typedef struct FFPerlin {
/**
* spatial repeat period, if negative it is ignored
*/
double period;
/**
* total number of components making up the noise, each one with
* doubled frequency
*/
int octaves;
/**
* ratio used to compute the amplitude of the next octave
* component with respect to the previous component
*/
double persistence;
/**
* permutations array used to compute the Perlin noise hash
*/
uint8_t permutations[512];
/**
* define how to compute the permutations array
*/
enum FFPerlinRandomMode random_mode;
/**
* when random_mode is set FF_PERLIN_RANDOM_MODE_RANDOM, set random
* seed used to compute the permutations array
*/
unsigned int random_seed;
} FFPerlin;
/**
* Initialize the Perlin noise generator with parameters.
*
* @param perlin Perlin noise generator context
* @param period spatial repeat period, if negative it is ignored
* @param octaves total number of components making up the noise, each one with doubled frequency
* @param persistence define ratio used to compute the amplitude of the next octave
* component with respect to the previous component
* @param random_mode define how to compute the permutations array
* @param random_seed when random_mode is set to FF_PERLIN_RANDOM_MODE_RANDOM, set random
* seed used to compute the permutations array
* @return a negative AVERROR code in case of error, a non negative value otherwise
*/
int ff_perlin_init(FFPerlin *perlin, double period, int octaves, double persistence,
enum FFPerlinRandomMode random_mode, unsigned int random_seed);
/**
* Compute Perlin noise given the x, y, z coordinates.
*
* @param perlin Perlin noise generator context
* @return normalized value for the perlin noise, in the range [0, 1]
*/
double ff_perlin_get(FFPerlin *perlin, double x, double y, double z);
#endif /* AVFILTER_PERLIN_H */
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