3 * Copyright (C) 2008 Filippo Argiolas <filippo.argiolas@gmail.com>
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Library General Public License for more details.
15 * You should have received a copy of the GNU Library General Public
16 * License along with this library; if not, write to the
17 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 * Boston, MA 02111-1307, USA.
21 #extension GL_ARB_texture_rectangle : enable
22 uniform sampler2DRect tex;
23 uniform float norm_const;
24 uniform float norm_offset;
25 uniform float kernel[9];
28 /* float offset[9] = float[9] (-4.0, -3.0, -2.0, -1.0, 0.0, 1.0, 2.0, 3.0, 4.0); */
29 /* don't use array constructor so we don't have to depend on #version 120 */
40 vec2 texturecoord = gl_TexCoord[0].st;
42 vec4 sum = vec4 (0.0);
43 for (i = 0; i < 9; i++) {
44 if (kernel[i] != 0.0) {
45 vec4 neighbor = texture2DRect(tex, vec2(texturecoord.s+offset[i], texturecoord.t));
46 sum += neighbor * kernel[i]/norm_const;
49 gl_FragColor = sum + norm_offset;