2016-07-24 12:46:42 +02:00
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/* Perlin noise generator.
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*
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* 24/7/16
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*/
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/*
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This file is part of VIPS.
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VIPS is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program 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
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA
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*/
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/*
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These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
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*/
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/*
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#define VIPS_DEBUG
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif /*HAVE_CONFIG_H*/
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#include <vips/intl.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <math.h>
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#include <vips/vips.h>
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#include "pcreate.h"
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typedef struct _VipsPerlin {
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VipsCreate parent_instance;
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int width;
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int height;
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int cell_size;
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2016-07-24 13:58:45 +02:00
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gboolean uchar;
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2016-07-24 12:46:42 +02:00
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int cells_across;
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int cells_down;
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/* Use this to seed this call of our rng.
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*/
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guint32 seed;
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} VipsPerlin;
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typedef struct _VipsPerlinClass {
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VipsCreateClass parent_class;
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} VipsPerlinClass;
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G_DEFINE_TYPE( VipsPerlin, vips_perlin, VIPS_TYPE_CREATE );
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/* cos and sin from an angle in 0 - 255.
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*/
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float vips_perlin_cos[256];
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float vips_perlin_sin[256];
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typedef struct _Sequence {
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VipsPerlin *perlin;
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/* The position of the last cell we were in. Use this to avoid
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* regenerating vectors on every pixel lookup.
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*/
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int cell_x;
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int cell_y;
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/* The 2 x 2 grid of unit vectors, with cell_x/cell_y as the top left.
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*/
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float gx[4];
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float gy[4];
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} Sequence;
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/* A very simple random number generator. See:
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* http://isthe.com/chongo/tech/comp/fnv/#FNV-source
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*/
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static guint32
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vips_perlin_random( guint32 seed )
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{
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return( 1103515245u * seed + 12345 );
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}
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static guint32
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vips_perlin_seed_add( guint32 seed, int value )
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{
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return( ((2166136261u ^ seed) * 16777619u) ^ value );
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}
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/* Generate a 3 x 3 grid of cells around a point.
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*/
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static void
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vips_perlin_create_cells( VipsPerlin *perlin,
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float gx[4], float gy[4], int cell_x, int cell_y )
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{
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int x, y;
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for( y = 0; y < 2; y++ )
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for( x = 0; x < 2; x++ ) {
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int ci = x + y * 2;
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guint32 seed;
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int cx;
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int cy;
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int angle;
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seed = perlin->seed;
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cx = cell_x + x;
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cy = cell_y + y;
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/* When we calculate the seed for this cell, we wrap
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* around so that our output will tesselate.
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*/
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if( cy >= perlin->cells_down )
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cy = 0;
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seed = vips_perlin_seed_add( seed, cy );
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2016-07-24 15:47:22 +02:00
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if( cx >= perlin->cells_across )
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cx = 0;
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seed = vips_perlin_seed_add( seed, cx );
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2016-07-24 12:46:42 +02:00
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seed = vips_perlin_random( seed );
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2016-07-24 15:47:22 +02:00
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angle = (seed ^ (seed >> 8) ^ (seed >> 16)) & 0xff;
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2016-07-24 12:46:42 +02:00
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gx[ci] = vips_perlin_cos[angle];
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gy[ci] = vips_perlin_sin[angle];
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}
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}
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static int
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vips_perlin_stop( void *vseq, void *a, void *b )
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{
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Sequence *seq = (Sequence *) vseq;
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VIPS_FREE( seq );
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return( 0 );
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}
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static void *
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vips_perlin_start( VipsImage *out, void *a, void *b )
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{
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VipsPerlin *perlin = (VipsPerlin *) b;
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Sequence *seq;
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if( !(seq = VIPS_NEW( NULL, Sequence )) )
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return( NULL );
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seq->perlin = perlin;
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seq->cell_x = -1;
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seq->cell_y = -1;
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return( seq );
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}
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2016-07-24 13:58:45 +02:00
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/* Smooth linear interpolation, 0 <= x <= 1.
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*
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* https://en.wikipedia.org/wiki/Smoothstep
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*/
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static float
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smootherstep( float x )
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{
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return( x * x * x * (x * (x * 6 - 15) + 10) );
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}
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2016-07-24 12:46:42 +02:00
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static int
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vips_perlin_gen( VipsRegion *or, void *vseq, void *a, void *b,
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gboolean *stop )
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{
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VipsPerlin *perlin = (VipsPerlin *) a;
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VipsRect *r = &or->valid;
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Sequence *seq = (Sequence *) vseq;
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int x, y;
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for( y = 0; y < r->height; y++ ) {
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2016-07-24 13:58:45 +02:00
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float *fq = (float *)
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VIPS_REGION_ADDR( or, r->left, r->top + y );
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VipsPel *q = (VipsPel *) fq;
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2016-07-24 12:46:42 +02:00
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for( x = 0; x < r->width; x++ ) {
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int cs = perlin->cell_size;
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int cell_x = (r->left + x) / cs;
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int cell_y = (r->top + y) / cs;
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float dx = (x + r->left - cell_x * cs) / (float) cs;
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float dy = (y + r->top - cell_y * cs) / (float) cs;
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2016-07-24 13:58:45 +02:00
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float sx = smootherstep( dx );
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float sy = smootherstep( dy );
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2016-07-24 12:46:42 +02:00
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float n0, n1;
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float ix0, ix1;
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2016-07-24 13:58:45 +02:00
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float p;
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2016-07-24 12:46:42 +02:00
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if( cell_x != seq->cell_x ||
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cell_y != seq->cell_y ) {
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vips_perlin_create_cells( perlin,
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seq->gx, seq->gy, cell_x, cell_y );
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seq->cell_x = cell_x;
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seq->cell_y = cell_y;
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}
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n0 = -dx * seq->gx[0] + -dy * seq->gy[0];
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n1 = (1 - dx) * seq->gx[1] + -dy * seq->gy[1];
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2016-07-24 13:58:45 +02:00
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ix0 = n0 + sx * (n1 - n0);
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2016-07-24 12:46:42 +02:00
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n0 = -dx * seq->gx[2] + (1 - dy) * seq->gy[2];
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n1 = (1 - dx) * seq->gx[3] + (1 - dy) * seq->gy[3];
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2016-07-24 13:58:45 +02:00
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ix1 = n0 + sx * (n1 - n0);
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2016-07-24 12:46:42 +02:00
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2016-07-24 13:58:45 +02:00
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p = ix0 + sy * (ix1 - ix0);
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if( perlin->uchar )
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q[x] = 128 * p + 128;
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else
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fq[x] = p;
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2016-07-24 12:46:42 +02:00
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}
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}
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return( 0 );
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}
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static int
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vips_perlin_build( VipsObject *object )
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{
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VipsCreate *create = VIPS_CREATE( object );
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VipsPerlin *perlin = (VipsPerlin *) object;
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if( VIPS_OBJECT_CLASS( vips_perlin_parent_class )->build( object ) )
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return( -1 );
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/* Be careful if width is a multiple of cell_size.
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*/
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2016-08-20 13:59:41 +02:00
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perlin->cells_across =
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VIPS_ROUND_UP( perlin->width, perlin->cell_size ) /
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2016-07-24 12:46:42 +02:00
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perlin->cell_size;
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2016-08-20 13:59:41 +02:00
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perlin->cells_down =
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VIPS_ROUND_UP( perlin->height, perlin->cell_size ) /
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2016-07-24 12:46:42 +02:00
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perlin->cell_size;
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perlin->seed = g_random_double() * 0xffffffffu;
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vips_image_init_fields( create->out,
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perlin->width, perlin->height, 1,
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2016-07-24 13:58:45 +02:00
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perlin->uchar ? VIPS_FORMAT_UCHAR : VIPS_FORMAT_FLOAT,
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VIPS_CODING_NONE, VIPS_INTERPRETATION_B_W,
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2016-07-24 12:46:42 +02:00
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1.0, 1.0 );
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vips_image_pipelinev( create->out,
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VIPS_DEMAND_STYLE_ANY, NULL );
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if( vips_image_generate( create->out,
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vips_perlin_start, vips_perlin_gen, vips_perlin_stop,
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perlin, NULL ) )
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return( -1 );
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return( 0 );
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}
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static void *
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vips_perlin_make_tables( void *client )
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{
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int i;
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for( i = 0; i < 256; i++ ) {
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double angle = 2 * M_PI * i / 256.0;
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vips_perlin_cos[i] = cos( angle );
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vips_perlin_sin[i] = sin( angle );
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}
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return( NULL );
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}
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static void
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vips_perlin_class_init( VipsPerlinClass *class )
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{
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GObjectClass *gobject_class = G_OBJECT_CLASS( class );
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VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
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static GOnce once = G_ONCE_INIT;
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(void) g_once( &once, vips_perlin_make_tables, NULL );
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gobject_class->set_property = vips_object_set_property;
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gobject_class->get_property = vips_object_get_property;
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vobject_class->nickname = "perlin";
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vobject_class->description = _( "make a perlin noise image" );
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vobject_class->build = vips_perlin_build;
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VIPS_ARG_INT( class, "width", 2,
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_( "Width" ),
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_( "Image width in pixels" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsPerlin, width ),
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1, VIPS_MAX_COORD, 1 );
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VIPS_ARG_INT( class, "height", 3,
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_( "Height" ),
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_( "Image height in pixels" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsPerlin, height ),
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1, VIPS_MAX_COORD, 1 );
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VIPS_ARG_INT( class, "cell_size", 3,
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_( "Cell size" ),
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_( "Size of Perlin cells" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT,
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G_STRUCT_OFFSET( VipsPerlin, cell_size ),
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1, VIPS_MAX_COORD, 256 );
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2016-07-24 13:58:45 +02:00
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VIPS_ARG_BOOL( class, "uchar", 4,
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_( "Uchar" ),
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_( "Output an unsigned char image" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT,
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G_STRUCT_OFFSET( VipsPerlin, uchar ),
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FALSE );
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2016-07-24 12:46:42 +02:00
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}
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static void
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vips_perlin_init( VipsPerlin *perlin )
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{
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perlin->cell_size = 256;
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}
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/**
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* vips_perlin:
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* @out: output image
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* @width: horizontal size
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* @height: vertical size
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* @...: %NULL-terminated list of optional named arguments
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*
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* Optional arguments:
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*
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* * @cell_size: %gint, size of Perlin cells
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2016-07-24 13:58:45 +02:00
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* * @uchar: output a uchar image
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2016-07-24 12:46:42 +02:00
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*
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* Create a one-band float image of Perlin noise. See:
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*
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* https://en.wikipedia.org/wiki/Perlin_noise
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*
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* Use @cell_size to set the size of the cells from which the image is
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* constructed. The default is 256 x 256.
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*
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* If @width and @height are multiples of @cell_size, the image will tessellate.
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*
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2016-07-24 13:58:45 +02:00
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* Normally, output pixels are #VIPS_FORMAT_FLOAT in the range [-1, +1]. Set
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* @uchar to output a uchar image with pixels in [0, 255].
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*
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2016-07-24 12:46:42 +02:00
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* See also: vips_worley(), vips_fractsurf(), vips_gaussnoise().
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*
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* Returns: 0 on success, -1 on error
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*/
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int
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vips_perlin( VipsImage **out, int width, int height, ... )
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{
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va_list ap;
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int result;
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va_start( ap, height );
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result = vips_call_split( "perlin", ap, out, width, height );
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va_end( ap );
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return( result );
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}
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