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/* GIMP - The GNU Image Manipulation Program
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
*
* 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 3 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, see <https://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <stdlib.h>
#include <gtk/gtk.h>
#include <libgimpmath/gimpmath.h>
#include <libgimp/gimp.h>
#include "gimpressionist.h"
#include "ppmtool.h"
#include "random.h"
static int
pfix (int n)
{
if (n < 1) return 1;
if (n > 255) return 255;
return n;
}
#define PIXEL(y,x,z) p->col[(y) * rowstride + (x) * 3 + z]
static void
mkplasma_sub (ppm_t *p, int x1, int x2, int y1, int y2, float turb)
{
int rowstride = p->width * 3;
int r=0;
int xr, yr, nx, ny;
xr = abs (x1 - x2);
yr = abs (y1 - y2);
if ((xr == 0) && (yr == 0))
return;
nx = (x1 + x2)/2;
ny = (y1 + y2)/2;
if (!PIXEL (y1,nx,r))
PIXEL (y1, nx, r) = pfix ((PIXEL (y1, x1, r) + PIXEL (y1, x2, r)) / 2.0 +
turb * g_rand_double_range (random_generator,
-xr / 2.0,
xr / 2.0));
if (!PIXEL (y2, nx, r))
PIXEL (y2, nx, r) = pfix ((PIXEL (y2, x1, r) + PIXEL (y2, x2, r)) / 2.0 +
turb * g_rand_double_range (random_generator,
-xr / 2.0,
xr / 2.0));
if (!PIXEL (ny, x1, r))
PIXEL (ny, x1, r) = pfix ((PIXEL (y1, x1, r)+PIXEL (y2, x1, r)) / 2.0 +
turb * g_rand_double_range (random_generator,
-yr / 2.0,
yr / 2.0));
if (!PIXEL (ny, x2, r))
PIXEL (ny, x2, r) = pfix ((PIXEL (y1, x2, r) + PIXEL (y2, x2, r)) / 2.0 +
turb * g_rand_double_range (random_generator,
-yr / 2.0,
yr / 2.0));
if (!PIXEL (ny, nx, r))
PIXEL (ny, nx, r) =
pfix ((PIXEL (y1, x1, r) + PIXEL (y1, x2, r) +
PIXEL (y2, x1, r) + PIXEL( y2, x2, r)) / 4.0 +
turb * g_rand_double_range (random_generator,
-(xr + yr)/4.0,
(xr + yr)/4.0));
if (xr>1)
{
mkplasma_sub (p, x1, nx, y1, ny, turb);
mkplasma_sub (p, nx, x2, y1, ny, turb);
}
if (yr>1)
{
mkplasma_sub (p, x1, nx, ny, y2, turb);
mkplasma_sub (p, nx, x2, ny, y2, turb);
}
}
static void
mkplasma_red (ppm_t *p, float turb)
{
int x = 0, y = 0;
int rowstride = p->width * 3;
for (x = 0; x < p->width; x++)
for (y = 0; y < p->height; y++)
PIXEL (y, x, 0) = 0;
x--; y--;
PIXEL (0, 0, 0) = g_rand_int_range (random_generator, 1, 256);
PIXEL (y, 0, 0) = g_rand_int_range (random_generator, 1, 256);
PIXEL (0, x, 0) = g_rand_int_range (random_generator, 1, 256);
PIXEL (y, x, 0) = g_rand_int_range (random_generator, 1, 256);
mkplasma_sub (p, 0, x, 0, y, turb);
}
void
mkgrayplasma (ppm_t *p, float turb)
{
int y, l;
mkplasma_red (p, turb);
l = p->width * 3 * p->height;
for (y = 0; y < l; y += 3)
p->col[y+1] = p->col[y+2] = p->col[y];
}
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