gstreamer/gst/geometrictransform/geometricmath.c

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/*
* GStreamer
* Copyright (C) 2010 Thiago Santos <thiago.sousa.santos@collabora.co.uk>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*
* Alternatively, the contents of this file may be used under the
* GNU Lesser General Public License Version 2.1 (the "LGPL"), in
* which case the following provisions apply instead of the ones
* mentioned above:
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/*
* Thanks to Jerry Huxtable <http://www.jhlabs.com> work on its java
* image editor and filters. The algorithms here were extracted from
* his code.
*/
#include "geometricmath.h"
#include <math.h>
#define N 0x1000
#define B 0x100
#define BM 0xff
struct _GstGMNoise
{
gdouble p[2 * B + 2];
gdouble g2[2 * B + 2][2];
};
static void
normalize_2 (gdouble * v)
{
gdouble s = sqrt (v[0] * v[0] + v[1] * v[1]);
v[0] = v[0] / s;
v[1] = v[1] / s;
}
GstGMNoise *
gst_gm_noise_new (void)
{
GstGMNoise *noise = g_new0 (GstGMNoise, 1);
gint i, j, k;
for (i = 0; i < B; i++) {
noise->p[i] = i;
for (j = 0; j < 2; j++) {
noise->g2[i][j] = ((g_random_int () % (2 * B))
- B) / (gdouble) B;
}
normalize_2 (noise->g2[i]);
}
for (i = B - 1; i >= 0; i--) {
k = noise->p[i];
j = g_random_int () % B;
noise->p[i] = noise->p[j];
noise->p[j] = k;
}
for (i = 0; i < B + 2; i++) {
noise->p[B + i] = noise->p[i];
for (j = 0; j < 2; j++) {
noise->g2[B + i][j] = noise->g2[i][j];
}
}
return noise;
}
void
gst_gm_noise_free (GstGMNoise * noise)
{
g_free (noise);
}
static gdouble
s_curve (gdouble x)
{
return x * x * (3.0 - 2.0 * x);
}
static gdouble
lerp (gdouble t, gdouble a, gdouble b)
{
return a + t * (b - a);
}
gdouble
gst_gm_noise_2 (GstGMNoise * noise, gdouble x, gdouble y)
{
gint bx0, bx1, by0, by1, b00, b10, b01, b11;
gdouble rx0, rx1, ry0, ry1, sx, sy, a, b, t, u, v;
gdouble *q;
gint i, j;
t = x + N;
bx0 = ((gint) t) & BM;
bx1 = (bx0 + 1) & BM;
rx0 = t - (gint) t;
rx1 = rx0 - 1.0;
t = y + N;
by0 = ((gint) t) & BM;
by1 = (by0 + 1) & BM;
ry0 = t - (gint) t;
ry1 = ry0 - 1.0;
i = noise->p[bx0];
j = noise->p[bx1];
b00 = noise->p[i + by0];
b10 = noise->p[j + by0];
b01 = noise->p[i + by1];
b11 = noise->p[j + by1];
sx = s_curve (rx0);
sy = s_curve (ry0);
q = noise->g2[b00];
u = rx0 * q[0] + ry0 * q[1];
q = noise->g2[b10];
v = rx1 * q[0] + ry0 * q[1];
a = lerp (sx, u, v);
q = noise->g2[b01];
u = rx0 * q[0] + ry1 * q[1];
q = noise->g2[b11];
v = rx1 * q[0] + ry1 * q[1];
b = lerp (sx, u, v);
return 1.5 * lerp (sy, a, b);
}
/*
* This differs from the % operator with respect to negative numbers
*/
gdouble
gst_gm_mod_float (gdouble a, gdouble b)
{
gint n = (gint) (a / b);
a -= n * b;
if (a < 0)
return a + b;
return a;
}
/**
* Returns a repeating triangle shape in the range 0..1 with wavelength 1.0
*/
gdouble
gst_gm_triangle (gdouble x)
{
gdouble r = gst_gm_mod_float (x, 1.0);
return 2.0 * (r < 0.5 ? r : 1 - r);
}
/**
* Hermite interpolation
*/
gdouble
gst_gm_smoothstep (gdouble edge0, gdouble edge1, gdouble x)
{
gdouble t = CLAMP ((x - edge0) / (edge1 - edge0), 0.0, 1.0);
return t * t * (3.0 - 2.0 * t);
}