mirror of
https://git.code.sf.net/p/quake/quakeforge
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149 lines
3.5 KiB
C
149 lines
3.5 KiB
C
/*
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noisetextures.c
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Noise texture generators
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noise_plasma
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Copyright (C) 2001 Ragnvald `Despair` Maartmann-Moe IV.
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noise_diamondsquare (originally fractalnoise)
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Copyright (C) 2000 Forest `LordHavoc` Hale.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (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.
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See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to:
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Free Software Foundation, Inc.
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59 Temple Place - Suite 330
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Boston, MA 02111-1307, USA
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*/
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static const char rcsid[] =
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"$Id$";
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#ifdef HAVE_STRING_H
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# include <string.h>
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#endif
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#ifdef HAVE_STRINGS_H
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# include <strings.h>
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#endif
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#include <stdlib.h>
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#include "QF/mathlib.h"
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#include "QF/sys.h"
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#include "compat.h"
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void
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noise_diamondsquare (unsigned char *noise, unsigned int size,
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unsigned int startgrid)
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{
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int amplitude, max, min;
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int size1 = size - 1;
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int *noisebuf;
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unsigned int gridpower, sizepower, g, g2, x, y;
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#define n(x, y) noisebuf[((y) & size1) * size + ((x) & size1)]
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for (sizepower = 0; (1 << sizepower) < size; sizepower++);
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if (size != (1 << sizepower))
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Sys_Error("fractalnoise: size must be power of 2");
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for (gridpower = 0; (1 << gridpower) < startgrid; gridpower++);
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if (startgrid != (1 << gridpower))
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Sys_Error("fractalnoise: grid must be power of 2");
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startgrid = bound(0, startgrid, size);
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amplitude = 0xFFFF; // this gets halved before use
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noisebuf = calloc (size * size, sizeof (int));
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memset(noisebuf, 0, size * size * sizeof(int));
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for (g2 = startgrid; g2; g2 >>= 1) {
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// Brownian Motion
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amplitude >>= 1;
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for (y = 0; y < size; y += g2)
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for (x = 0; x < size; x += g2)
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n (x,y) += (rand () & amplitude);
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g = g2 >> 1;
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if (g) {
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// subdivide, diamond-square algorithm
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// diamond
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for (y = 0; y < size; y += g2)
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for (x = 0; x < size; x += g2)
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n (x + g, y + g) =
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(n (x, y) + n (x + g2, y) + n (x, y + g2) +
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n (x + g2, y + g2)) >> 2;
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// square
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for (y = 0; y < size; y += g2)
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for (x = 0; x < size; x += g2) {
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n (x + g, y) = (n (x, y) + n (x + g2, y) +
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n (x + g, y - g) + n (x + g, y + g)) >> 2;
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n (x, y + g) = (n (x, y) + n (x, y + g2) +
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n (x - g, y + g) + n (x + g, y + g)) >> 2;
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}
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}
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}
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// find range of noise values
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min = max = 0;
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for (y = 0; y < size; y++)
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for (x = 0; x < size; x++) {
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if (n (x, y) < min)
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min = n (x, y);
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if (n (x, y) > max)
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max = n (x, y);
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}
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max -= min;
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max++;
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// normalize noise and copy to output
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for (y = 0; y < size; y++)
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for (x = 0; x < size; x++)
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*noise++ = (unsigned char) (((n (x, y) - min) * 256) / max);
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free (noisebuf);
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#undef n
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}
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void
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noise_plasma (unsigned char *noise, int size)
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{
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unsigned int a, b, c, d, i, j, k;
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if (128 >= size)
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d = 64 / size;
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else
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d = -size / 64;
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memset(noise, 128, sizeof (*noise));
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for (i = size; i > 0; i /= 2) {
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for (j=0; j < size; j += i) {
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for (k=0; k < size; k += i) {
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if (d >= 0)
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c = i * d;
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else
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c = -i / d;
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c = qfrandom (c * 2) - c;
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for (a=j; a < j + i; a++)
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for (b = k; b < k + i; b++)
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noise[a * size + b] += c;
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}
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}
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}
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}
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