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, write to
17 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
18 * http://www.gnu.org/copyleft/gpl.html
22 uniform sampler2D img;
24 uniform float m_stretch;
28 uniform sampler1D kernelTex;
30 uniform sampler2D kernelTex;
33 //nvidia's half is a 16 bit float and can bring some speed improvements
34 //without affecting quality
35 #ifndef __GLSL_CG_DATA_TYPES
41 half3 weight(float pos)
43 #if (HAS_FLOAT_TEXTURE)
45 return texture1D(kernelTex, pos).rgb;
47 return texture2D(kernelTex, vec2(pos, 0.5)).rgb;
51 return texture1D(kernelTex, pos).rgb * 2.0 - 1.0;
53 return texture2D(kernelTex, vec2(pos, 0.5)).rgb * 2.0 - 1.0;
58 vec2 stretch(vec2 pos)
61 // 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.
62 // a simple curve to do this is g(x) = b(x-0.5) + (1-b)2^(n-1)(x-0.5)^n + 0.5
63 // where the power preserves sign. n = 2 is the simplest non-linear case (required when b != 1)
64 float x = pos.x - 0.5;
65 return vec2(mix(x * abs(x) * 2.0, x, m_stretch) + 0.5, pos.y);
71 half3 pixel(float xpos, float ypos)
73 return texture2D(img, vec2(xpos, ypos)).rgb;
76 half3 line (float ypos, vec3 xpos1, vec3 xpos2, half3 linetaps1, half3 linetaps2)
79 pixel(xpos1.r, ypos) * linetaps1.r +
80 pixel(xpos1.g, ypos) * linetaps2.r +
81 pixel(xpos1.b, ypos) * linetaps1.g +
82 pixel(xpos2.r, ypos) * linetaps2.g +
83 pixel(xpos2.g, ypos) * linetaps1.b +
84 pixel(xpos2.b, ypos) * linetaps2.b;
89 vec2 pos = stretch(cord) + stepxy * 0.5;
90 vec2 f = fract(pos / stepxy);
92 half3 linetaps1 = weight((1.0 - f.x) / 2.0);
93 half3 linetaps2 = weight((1.0 - f.x) / 2.0 + 0.5);
94 half3 columntaps1 = weight((1.0 - f.y) / 2.0);
95 half3 columntaps2 = weight((1.0 - f.y) / 2.0 + 0.5);
97 //make sure all taps added together is exactly 1.0, otherwise some (very small) distortion can occur
98 half sum = linetaps1.r + linetaps1.g + linetaps1.b + linetaps2.r + linetaps2.g + linetaps2.b;
101 sum = columntaps1.r + columntaps1.g + columntaps1.b + columntaps2.r + columntaps2.g + columntaps2.b;
105 vec2 xystart = (-2.5 - f) * stepxy + pos;
106 vec3 xpos1 = vec3(xystart.x, xystart.x + stepxy.x, xystart.x + stepxy.x * 2.0);
107 vec3 xpos2 = vec3(xystart.x + stepxy.x * 3.0, xystart.x + stepxy.x * 4.0, xystart.x + stepxy.x * 5.0);
110 line(xystart.y , xpos1, xpos2, linetaps1, linetaps2) * columntaps1.r +
111 line(xystart.y + stepxy.y , xpos1, xpos2, linetaps1, linetaps2) * columntaps2.r +
112 line(xystart.y + stepxy.y * 2.0, xpos1, xpos2, linetaps1, linetaps2) * columntaps1.g +
113 line(xystart.y + stepxy.y * 3.0, xpos1, xpos2, linetaps1, linetaps2) * columntaps2.g +
114 line(xystart.y + stepxy.y * 4.0, xpos1, xpos2, linetaps1, linetaps2) * columntaps1.b +
115 line(xystart.y + stepxy.y * 5.0, xpos1, xpos2, linetaps1, linetaps2) * columntaps2.b;
117 gl_FragColor.a = gl_Color.a;