/system/shaders/stretch.glsl
http://github.com/xbmc/xbmc · GLSL · 39 lines · 13 code · 4 blank · 22 comment · 0 complexity · 0101af42ce7633db5753c2543444c741 MD5 · raw file
- /*
- * Copyright (C) 2010-2013 Team XBMC
- * http://xbmc.org
- *
- * 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, 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 XBMC; see the file COPYING. If not, see
- * <http://www.gnu.org/licenses/>.
- *
- */
- uniform sampler2D img;
- uniform float m_stretch;
- varying vec2 cord;
- vec2 stretch(vec2 pos)
- {
- // our transform should map [0..1] to itself, with f(0) = 0, f(1) = 1, f(0.5) = 0.5, and f'(0.5) = b.
- // a simple curve to do this is g(x) = b(x-0.5) + (1-b)2^(n-1)(x-0.5)^n + 0.5
- // where the power preserves sign. n = 2 is the simplest non-linear case (required when b != 1)
- float x = pos.x - 0.5;
- return vec2(mix(x * abs(x) * 2.0, x, m_stretch) + 0.5, pos.y);
- }
- void main()
- {
- gl_FragColor.rgb = texture2D(img, stretch(cord)).rgb;
- gl_FragColor.a = gl_Color.a;
- }