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102 lines
3.1 KiB
C
102 lines
3.1 KiB
C
/*
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* Perlin noise generator
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Perlin Noise generator
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*/
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#ifndef AVFILTER_PERLIN_H
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#define AVFILTER_PERLIN_H
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#include <stdint.h>
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enum FFPerlinRandomMode {
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FF_PERLIN_RANDOM_MODE_RANDOM,
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FF_PERLIN_RANDOM_MODE_KEN,
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FF_PERLIN_RANDOM_MODE_SEED,
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FF_PERLIN_RANDOM_MODE_NB
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};
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/**
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* Perlin generator context. This needs to be initialized with the
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* parameters used to generate the Perlin noise.
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*/
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typedef struct FFPerlin {
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/**
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* spatial repeat period, if negative it is ignored
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*/
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double period;
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/**
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* total number of components making up the noise, each one with
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* doubled frequency
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*/
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int octaves;
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/**
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* ratio used to compute the amplitude of the next octave
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* component with respect to the previous component
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*/
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double persistence;
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/**
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* permutations array used to compute the Perlin noise hash
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*/
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uint8_t permutations[512];
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/**
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* define how to compute the permutations array
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*/
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enum FFPerlinRandomMode random_mode;
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/**
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* when random_mode is set FF_PERLIN_RANDOM_MODE_RANDOM, set random
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* seed used to compute the permutations array
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*/
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unsigned int random_seed;
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} FFPerlin;
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/**
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* Initialize the Perlin noise generator with parameters.
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*
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* @param perlin Perlin noise generator context
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* @param period spatial repeat period, if negative it is ignored
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* @param octaves total number of components making up the noise, each one with doubled frequency
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* @param persistence define ratio used to compute the amplitude of the next octave
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* component with respect to the previous component
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* @param random_mode define how to compute the permutations array
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* @param random_seed when random_mode is set to FF_PERLIN_RANDOM_MODE_RANDOM, set random
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* seed used to compute the permutations array
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* @return a negative AVERROR code in case of error, a non negative value otherwise
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*/
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int ff_perlin_init(FFPerlin *perlin, double period, int octaves, double persistence,
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enum FFPerlinRandomMode random_mode, unsigned int random_seed);
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/**
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* Compute Perlin noise given the x, y, z coordinates.
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*
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* @param perlin Perlin noise generator context
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* @return normalized value for the perlin noise, in the range [0, 1]
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*/
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double ff_perlin_get(FFPerlin *perlin, double x, double y, double z);
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#endif /* AVFILTER_PERLIN_H */
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