1 // NTSC Shader - written by Hans-Kristian Arntzen
3 // pulled from git://github.com/libretro/common-shaders.git on 01/30/2014
5 precision mediump float;
6 uniform bool swap_byteorder;
8 varying mediump vec2 v_texcoord;
10 uniform sampler2D a_texture;
11 uniform vec4 source_size;
12 uniform vec4 target_size;
15 uniform float luma_filter[24 + 1];
16 uniform float chroma_filter[24 + 1];
18 #define GAMMA_CORRECTION //comment to disable gamma correction, usually because higan's gamma correction is enabled or you have another shader already doing it
20 #define DISPLAY_GAMMA 2.1
23 // #include ntsc-rgbyuv.inc //
24 mat3 yiq2rgb_mat = mat3(
26 0.956, -0.2720, -1.1060,
30 vec3 yiq2rgb(vec3 yiq)
32 return (yiq * yiq2rgb_mat);
35 mat3 ycbcr_mat = mat3(
36 0.29891, -0.16874, 0.50000,
37 0.58661, -0.33126, -0.41869,
38 0.11448, 0.50000, -0.08131
40 vec3 rgb2ycbcr(vec3 col)
42 vec3 ycbcr = col * ycbcr_mat;
46 mat3 ycbcr2rgb_mat = mat3(
48 0.0, -0.34414 , 1.77200,
49 1.40200, -0.71414, 0.0
52 vec3 ycbcr2rgb(vec3 ycbcr)
54 //vec3 ra = ycbcr * vec3(1.0, 0.7, 1.0);
55 return (ycbcr * ycbcr2rgb_mat);
59 0.2989, 0.5959, 0.2115,
60 0.5870, -0.2744, -0.5229,
61 0.1140, -0.3216, 0.3114
64 vec3 rgb2yiq(vec3 col)
66 return (col * yiq_mat);
68 // END ntsc-rgbyuv.inc //
70 // fixCoord moved from vertex
71 #define fixCoord (v_texcoord - vec2(0.5 / source_size.x, 0.0)) // Compensate for decimate-by-2.
73 #define fetch_offset(offset, one_x) \
74 texture2D(a_texture, fixCoord + vec2((offset) * (one_x), 0.0)).xyz
78 // #include "ntsc-pass2-decode.inc" //
79 float one_x = 1.0 / source_size.x;
80 vec3 signal = vec3(0.0);
84 for (int ii = 1; ii < TAPS; ii++)
86 float offset = float(ii);
87 vec3 sums = fetch_offset(offset - float(TAPS), one_x) +
88 fetch_offset(float(TAPS) - offset, one_x);
89 sums = sums * vec3(3.6, 1.7, 1.7);
90 signal += sums * vec3(luma_filter[ii], chroma_filter[ii], chroma_filter[ii]);
93 float pos_offset = float(TAPS - ibegin) * one_x;
94 vec3 sums_p = vec3(0.0, 0.0, 0.0);
96 vec2 fix_coord = v_texcoord - vec2(0.5 / source_size.x, 0.0);
97 vec2 delta = vec2(one_x, 0);
100 vec2 addr_p = fix_coord + vec2(pos_offset, 0);
101 vec2 addr_n = fix_coord - vec2(pos_offset, 0);
103 for(int ii = 1; ii < TAPS; ii++) {
104 pix_p = texture2D(a_texture, addr_p).xyz;
105 pix_n = texture2D(a_texture, addr_n).xyz;
106 pix_p = pix_p * vec3(3.6, 1.7, 1.7);
107 pix_n = pix_n * vec3(3.6, 1.7, 1.7);
108 pix_p = (pix_n + pix_p) * vec3(luma_filter[ii], chroma_filter[ii], chroma_filter[ii]);
109 signal = signal + pix_p;
110 addr_p = addr_p - delta;
111 addr_n = addr_n + delta;
114 vec3 _tmpvar = texture2D(a_texture, fixCoord).xyz;
115 // yMax = (0.299+0.587+0.114) * (+-1.0) * (BRIGHTNESS + ARTIFACTING + ARTIFACTING) * (+-1.0)
116 // CbMax = (-0.168736 -0.331264 + 0.5) * (+-1.0) * (FRINGING + 2*SATURATION) * (+-1.0)
117 // CrMax = (0.5 - 0.418688 - 0.081312) * (+-1.0) * (FRINGING + 2*SATURATION) * (+-1.0)
121 _tmpvar = _tmpvar * vec3(3.6, 1.7, 1.7);
122 vec3 texvar = _tmpvar;
123 signal += texvar * vec3(luma_filter[TAPS], chroma_filter[TAPS], chroma_filter[TAPS]);
124 // END "ntsc-pass2-decode.inc" //
126 vec3 rgb = ycbcr2rgb(signal);
127 rgb = rgb * vec3(0.67, 1.0, 1.0);
128 #ifdef GAMMA_CORRECTION
129 vec3 gamma = vec3(CRT_GAMMA / DISPLAY_GAMMA);
130 rgb = pow(abs(rgb), gamma.rgb);
132 vec4 pixel = vec4(rgb, 1.0);
134 pixel.rgba = pixel.bgra;
135 gl_FragColor = pixel;
137 gl_FragColor = pixel;