2 * Copyright (C) 2010-2013 Team XBMC
5 * This Program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2, or (at your option)
10 * This Program 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
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with XBMC; see the file COPYING. If not, see
17 * <http://www.gnu.org/licenses/>.
21 uniform sampler2D img;
23 uniform float m_stretch;
27 uniform sampler1D kernelTex;
29 uniform sampler2D kernelTex;
32 //nvidia's half is a 16 bit float and can bring some speed improvements
33 //without affecting quality
34 #ifndef __GLSL_CG_DATA_TYPES
40 half4 weight(float pos)
42 #if (HAS_FLOAT_TEXTURE)
44 return texture1D(kernelTex, pos);
46 return texture2D(kernelTex, vec2(pos, 0.5));
50 return texture1D(kernelTex, pos) * 2.0 - 1.0;
52 return texture2D(kernelTex, vec2(pos, 0.5)) * 2.0 - 1.0;
57 vec2 stretch(vec2 pos)
60 // 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.
61 // a simple curve to do this is g(x) = b(x-0.5) + (1-b)2^(n-1)(x-0.5)^n + 0.5
62 // where the power preserves sign. n = 2 is the simplest non-linear case (required when b != 1)
63 float x = pos.x - 0.5;
64 return vec2(mix(x * abs(x) * 2.0, x, m_stretch) + 0.5, pos.y);
70 half3 pixel(float xpos, float ypos)
72 return texture2D(img, vec2(xpos, ypos)).rgb;
75 half3 line (float ypos, vec4 xpos, half4 linetaps)
78 pixel(xpos.r, ypos) * linetaps.r +
79 pixel(xpos.g, ypos) * linetaps.g +
80 pixel(xpos.b, ypos) * linetaps.b +
81 pixel(xpos.a, ypos) * linetaps.a;
86 vec2 pos = stretch(cord) + stepxy * 0.5;
87 vec2 f = fract(pos / stepxy);
89 half4 linetaps = weight(1.0 - f.x);
90 half4 columntaps = weight(1.0 - f.y);
92 //make sure all taps added together is exactly 1.0, otherwise some (very small) distortion can occur
93 linetaps /= linetaps.r + linetaps.g + linetaps.b + linetaps.a;
94 columntaps /= columntaps.r + columntaps.g + columntaps.b + columntaps.a;
96 vec2 xystart = (-1.5 - f) * stepxy + pos;
97 vec4 xpos = vec4(xystart.x, xystart.x + stepxy.x, xystart.x + stepxy.x * 2.0, xystart.x + stepxy.x * 3.0);
100 line(xystart.y , xpos, linetaps) * columntaps.r +
101 line(xystart.y + stepxy.y , xpos, linetaps) * columntaps.g +
102 line(xystart.y + stepxy.y * 2.0, xpos, linetaps) * columntaps.b +
103 line(xystart.y + stepxy.y * 3.0, xpos, linetaps) * columntaps.a;
105 gl_FragColor.a = gl_Color.a;