/system/shaders/convolution-6x6.glsl

http://github.com/xbmc/xbmc · GLSL · 120 lines · 81 code · 14 blank · 25 comment · 0 complexity · 357da8c6f85ef284f7f9a06fc1fbd795 MD5 · raw file

  1. /*
  2. * Copyright (C) 2010-2013 Team XBMC
  3. * http://xbmc.org
  4. *
  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)
  8. * any later version.
  9. *
  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.
  14. *
  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/>.
  18. *
  19. */
  20. uniform sampler2D img;
  21. uniform vec2 stepxy;
  22. uniform float m_stretch;
  23. varying vec2 cord;
  24. #if (USE1DTEXTURE)
  25. uniform sampler1D kernelTex;
  26. #else
  27. uniform sampler2D kernelTex;
  28. #endif
  29. //nvidia's half is a 16 bit float and can bring some speed improvements
  30. //without affecting quality
  31. #ifndef __GLSL_CG_DATA_TYPES
  32. #define half float
  33. #define half3 vec3
  34. #define half4 vec4
  35. #endif
  36. half3 weight(float pos)
  37. {
  38. #if (HAS_FLOAT_TEXTURE)
  39. #if (USE1DTEXTURE)
  40. return texture1D(kernelTex, pos).rgb;
  41. #else
  42. return texture2D(kernelTex, vec2(pos, 0.5)).rgb;
  43. #endif
  44. #else
  45. #if (USE1DTEXTURE)
  46. return texture1D(kernelTex, pos).rgb * 2.0 - 1.0;
  47. #else
  48. return texture2D(kernelTex, vec2(pos, 0.5)).rgb * 2.0 - 1.0;
  49. #endif
  50. #endif
  51. }
  52. vec2 stretch(vec2 pos)
  53. {
  54. #if (XBMC_STRETCH)
  55. // 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.
  56. // a simple curve to do this is g(x) = b(x-0.5) + (1-b)2^(n-1)(x-0.5)^n + 0.5
  57. // where the power preserves sign. n = 2 is the simplest non-linear case (required when b != 1)
  58. float x = pos.x - 0.5;
  59. return vec2(mix(x * abs(x) * 2.0, x, m_stretch) + 0.5, pos.y);
  60. #else
  61. return pos;
  62. #endif
  63. }
  64. half3 pixel(float xpos, float ypos)
  65. {
  66. return texture2D(img, vec2(xpos, ypos)).rgb;
  67. }
  68. half3 line (float ypos, vec3 xpos1, vec3 xpos2, half3 linetaps1, half3 linetaps2)
  69. {
  70. return
  71. pixel(xpos1.r, ypos) * linetaps1.r +
  72. pixel(xpos1.g, ypos) * linetaps2.r +
  73. pixel(xpos1.b, ypos) * linetaps1.g +
  74. pixel(xpos2.r, ypos) * linetaps2.g +
  75. pixel(xpos2.g, ypos) * linetaps1.b +
  76. pixel(xpos2.b, ypos) * linetaps2.b;
  77. }
  78. vec4 process()
  79. {
  80. vec4 rgb;
  81. vec2 pos = stretch(cord) + stepxy * 0.5;
  82. vec2 f = fract(pos / stepxy);
  83. half3 linetaps1 = weight((1.0 - f.x) / 2.0);
  84. half3 linetaps2 = weight((1.0 - f.x) / 2.0 + 0.5);
  85. half3 columntaps1 = weight((1.0 - f.y) / 2.0);
  86. half3 columntaps2 = weight((1.0 - f.y) / 2.0 + 0.5);
  87. //make sure all taps added together is exactly 1.0, otherwise some (very small) distortion can occur
  88. half sum = linetaps1.r + linetaps1.g + linetaps1.b + linetaps2.r + linetaps2.g + linetaps2.b;
  89. linetaps1 /= sum;
  90. linetaps2 /= sum;
  91. sum = columntaps1.r + columntaps1.g + columntaps1.b + columntaps2.r + columntaps2.g + columntaps2.b;
  92. columntaps1 /= sum;
  93. columntaps2 /= sum;
  94. vec2 xystart = (-2.5 - f) * stepxy + pos;
  95. vec3 xpos1 = vec3(xystart.x, xystart.x + stepxy.x, xystart.x + stepxy.x * 2.0);
  96. vec3 xpos2 = vec3(xystart.x + stepxy.x * 3.0, xystart.x + stepxy.x * 4.0, xystart.x + stepxy.x * 5.0);
  97. rgb =
  98. line(xystart.y , xpos1, xpos2, linetaps1, linetaps2) * columntaps1.r +
  99. line(xystart.y + stepxy.y , xpos1, xpos2, linetaps1, linetaps2) * columntaps2.r +
  100. line(xystart.y + stepxy.y * 2.0, xpos1, xpos2, linetaps1, linetaps2) * columntaps1.g +
  101. line(xystart.y + stepxy.y * 3.0, xpos1, xpos2, linetaps1, linetaps2) * columntaps2.g +
  102. line(xystart.y + stepxy.y * 4.0, xpos1, xpos2, linetaps1, linetaps2) * columntaps1.b +
  103. line(xystart.y + stepxy.y * 5.0, xpos1, xpos2, linetaps1, linetaps2) * columntaps2.b;
  104. rgb.a = gl_Color.a;
  105. return rgb;
  106. }