quakeforge/libs/video/renderer/gl/noisetextures.c

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