/**
 * Blue Noise texture created by Christoph Peters, released under CC0
 * http://momentsingraphics.de/BlueNoise.html
 */

#version 120
#ifdef GL_ES
    precision mediump float;
#endif


varying vec4 v_color;
varying vec2 v_texCoords;
uniform sampler2D u_texture;

vec4 bayerTex[256] = vec4[](
vec4(205, 111,  82,  65),
vec4(255,  65, 133,   0),
vec4( 25,  88,   9, 134),
vec4(105, 231,  39, 185),
vec4(161, 152, 139,  66),
vec4( 91, 170, 203,  35),
vec4(247,  78,   3, 115),
vec4( 22, 193,  59, 144),
vec4(165, 156, 148, 157),
vec4(114, 131, 233, 245),
vec4(192, 202, 132,  57),
vec4( 30, 162,  31,  15),
vec4(217,  17,  63,  83),
vec4(147, 189, 214,  39),
vec4( 71, 168, 106, 129),
vec4(135,   1, 195, 243),
vec4(173, 213, 232,  75),
vec4(122, 175, 161, 233),
vec4(142,  26, 213, 203),
vec4(234, 118, 251,  21),
vec4(  1,   7,  70,  86),
vec4(218, 222, 113, 162),
vec4(150, 105, 244, 249),
vec4(186,  51, 124,  49),
vec4( 41, 229, 183,  11),
vec4( 65,   4,  22,  90),
vec4(252,  43, 115, 186),
vec4(131, 141, 166, 165),
vec4( 53, 221, 239, 202),
vec4( 20,  69,   1, 228),
vec4(226, 230, 123, 173),
vec4( 39, 130,  43,  29),
vec4( 15, 251,  28, 124),
vec4(216,  79,  90,  98),
vec4( 47, 137,  53, 145),
vec4(198, 203, 197, 225),
vec4( 60, 190,  25,  54),
vec4(133,  38, 172, 130),
vec4( 75, 143,  46, 218),
vec4(124, 243,  97, 105),
vec4(227, 115, 218, 201),
vec4( 84,  81,  68, 123),
vec4(  4,  97, 207,  32),
vec4(179, 254,  84, 133),
vec4( 79,  55,  50,  99),
vec4(160, 119, 184,   9),
vec4(189,  92, 141, 108),
vec4( 86,  47, 246, 194),
vec4(111, 185,  67,  48),
vec4(157,  14, 147, 170),
vec4( 70,  54, 122,  12),
vec4( 98, 235, 105, 110),
vec4(180,  70, 155, 197),
vec4( 31,  94,  85, 177),
vec4(239,  21, 224,   4),
vec4( 14, 167,  30,  78),
vec4(106, 183, 162, 172),
vec4(209, 212,   6, 234),
vec4(144, 151, 254, 221),
vec4(235, 178, 103,  73),
vec4(101,  23, 151, 250),
vec4(119, 205, 221,  60),
vec4(248, 154,  13, 156),
vec4( 59,  31, 168, 217),
vec4(238, 144, 209, 238),
vec4(177, 223, 227,  37),
vec4( 11, 165, 182, 154),
vec4(249, 108,   5, 254),
vec4(164, 153, 238,  74),
vec4(112, 253, 128,  30),
vec4(201, 126, 190, 239),
vec4( 49,  59, 145, 139),
vec4(172,  11,  78,  63),
vec4(156,  32, 200,  20),
vec4( 27,  72, 135,  46),
vec4( 44, 107,  38, 148),
vec4(196, 192, 193, 180),
vec4(  9,   6,  72,  24),
vec4(208, 242,  96, 140),
vec4(138, 102, 114,  84),
vec4( 34, 199,  19, 182),
vec4( 81, 122,  45,  64),
vec4(128,  91,  79, 208),
vec4(211,  28,  36,  92),
vec4( 23,  44, 212, 122),
vec4( 83, 187,  58,  44),
vec4(139, 216,  11, 190),
vec4(223,  85, 241,  96),
vec4( 92, 198, 117, 159),
vec4( 58, 232,  55, 113),
vec4(129, 136, 173, 193),
vec4(215, 238,  15,  85),
vec4( 69,  62, 125, 211),
vec4(166, 129, 243, 118),
vec4( 26, 172,  54, 242),
vec4( 95,  73, 179,   6),
vec4(224,  57, 129, 106),
vec4(199,   8, 252, 127),
vec4(145, 247, 164, 227),
vec4( 43, 209, 201,  18),
vec4(229, 173, 137, 168),
vec4(154,   0,  71, 150),
vec4( 67, 140, 177, 216),
vec4(  3, 104, 102,  14),
vec4(194, 160,  41, 206),
vec4(245, 121, 229, 252),
vec4(181,  41,  93, 128),
vec4(110, 164, 236,   1),
vec4(241,  25, 160, 166),
vec4(149,  86,  29,  40),
vec4( 50, 225, 204,  70),
vec4(183,  40, 143, 198),
vec4( 64, 159, 231, 163),
vec4(  2, 179, 104,  26),
vec4(115, 133,  91,  79),
vec4( 56,  63,  23, 188),
vec4( 97, 116, 112,  58),
vec4(187,  77, 247, 246),
vec4(254, 226, 158, 114),
vec4( 37,  50,  18,  82),
vec4(120, 249, 205,  53),
vec4( 78,  19, 150,  33),
vec4( 13,  95, 186, 224),
vec4( 36, 219,  64, 103),
vec4( 87, 197, 110,  55),
vec4(127, 147, 216, 230),
vec4(213, 114,  87,  95),
vec4(108, 208,   2, 137),
vec4(236, 233, 192, 251),
vec4(169,  20,  57,  50),
vec4(193,  84, 153, 204),
vec4(242, 149, 188, 142),
vec4(125, 240, 225, 101),
vec4( 19,  36,  48,   8),
vec4(176, 194,  86, 132),
vec4(103,  15, 215, 232),
vec4(162,  67, 121, 181),
vec4(220, 206,  26, 143),
vec4(140, 180,  80,  69),
vec4(171,  74,   7, 171),
vec4(230,  52, 140, 189),
vec4(  6, 250,  42, 149),
vec4( 77,  13, 175, 215),
vec4(155,  98,  74,  16),
vec4(136,  68,  34, 176),
vec4( 21, 195, 217, 116),
vec4( 88,  48,  14, 241),
vec4( 33, 220,  66,  38),
vec4(210, 182, 171, 222),
vec4( 76,  96,  32, 175),
vec4(134, 155, 131,  71),
vec4( 54, 127, 185,  41),
vec4(206, 171,  61, 158),
vec4( 24, 145, 248,  91),
vec4( 99, 112, 167,  22),
vec4(202,   2, 222, 244),
vec4( 62, 125, 196,  10),
vec4(188, 184, 250, 121),
vec4(253,  35, 120,  34),
vec4( 40, 139, 157,  88),
vec4(102, 106, 107, 152),
vec4( 72, 255, 134,  68),
vec4(219, 123, 240,   2),
vec4(151,  30, 118, 160),
vec4(163,  10, 146,  89),
vec4(  8, 109,  99, 210),
vec4(222, 236, 230,  27),
vec4(237, 214,   0, 196),
vec4(148,  87, 144, 120),
vec4( 68,  37, 108, 219),
vec4(250, 246,  49, 199),
vec4( 48, 228, 130, 111),
vec4(132, 158,  98,  80),
vec4(116,  83,  60, 236),
vec4( 18, 215,  24,  61),
vec4(175, 169, 237, 192),
vec4( 52,   5, 181, 231),
vec4(244, 157,  47,  97),
vec4(184,  90,  81, 187),
vec4(109, 204, 208, 126),
vec4( 61, 142,  10,  51),
vec4(190,  53, 255, 109),
vec4(117,  71,  73, 147),
vec4( 42,  24, 199, 240),
vec4( 89, 188,  89,   3),
vec4( 10,  58, 234,  59),
vec4(182, 101,  33, 135),
vec4(158, 135, 211,  47),
vec4( 29,  27,  12, 155),
vec4( 93,  64, 149, 207),
vec4(221, 239,  88, 131),
vec4(207,  45, 202,  42),
vec4(123, 132,   4,  13),
vec4(  7, 227, 165, 138),
vec4(141,  60,  95, 200),
vec4( 45, 174, 194, 226),
vec4(251, 244,  40,  19),
vec4( 96, 163, 178, 253),
vec4( 28, 201,  52, 183),
vec4(197, 120, 163,  77),
vec4(168, 224,  20, 104),
vec4(126,  12, 180, 164),
vec4(107, 166, 154, 248),
vec4(225, 196,  76, 179),
vec4(195, 207, 189,  28),
vec4(143,  93, 170, 100),
vec4( 82, 117, 228, 167),
vec4(159, 191,  69, 220),
vec4( 32,  75, 142, 112),
vec4(200, 210, 245,  56),
vec4( 85,  34,  27,  31),
vec4( 16, 113, 152,  81),
vec4(130,  80, 219, 169),
vec4(231,   3, 127,  62),
vec4(146, 134, 109, 136),
vec4( 80,  42, 136,  45),
vec4(243, 148, 210, 205),
vec4(214, 237,  65,  17),
vec4( 38,  76, 119,  87),
vec4( 73,  49, 242, 223),
vec4(246,   9,  51,  67),
vec4(  0, 150, 111,   5),
vec4( 63, 176,  37, 255),
vec4(233,  22, 126,  76),
vec4(113, 100,  56, 146),
vec4(153, 146, 223, 214),
vec4(228,  16, 116, 247),
vec4(170, 186,  62, 119),
vec4(212, 217,  77, 153),
vec4( 66,  99,  16,   7),
vec4(178, 252, 226,  94),
vec4(  5, 177,  35, 229),
vec4(137,  89, 249, 174),
vec4( 57, 110, 101, 125),
vec4( 17, 181,   8,  36),
vec4(174, 124, 220, 141),
vec4(121, 218, 138, 195),
vec4( 46, 234,  17, 117),
vec4(167,  56, 253, 184),
vec4(185, 248, 206,  23),
vec4( 94, 200,  21, 161),
vec4( 55, 161, 100, 178),
vec4( 74, 241, 187,  43),
vec4(191,  46, 169, 102),
vec4( 35, 128, 235, 235),
vec4(118,  61,  94, 209),
vec4( 51,  29, 159, 191),
vec4(204, 211, 191,  25),
vec4(100,  18,  83,  72),
vec4(232,  66,  44, 213),
vec4(152, 245, 174, 107),
vec4( 90,  33, 198, 237),
vec4(203, 103,  92, 151),
vec4(104,  82, 156,  52),
vec4(240, 138,  75, 212),
vec4( 12,  39, 176,  93)
);

float bayerSize = 16.0;
float bayerDivider = bayerSize * bayerSize;

float quant = 63.0; // 64 steps -> 63.0; 256 steps -> 255.0
vec4 quantiser = vec4(quant);
vec4 quantiserDivider = vec4(1.0 / quant);

vec2 boolean = vec2(0.0, 1.0);
vec4 halfvec = vec4(0.5);

vec4 gammaIn(vec4 col) {
    return pow(col, vec4(2.2));
}

vec4 gammaOut(vec4 col) {
    return pow(col, vec4(1.0 / 2.2));
}

vec4 nearestColour(vec4 inColor) {
    return floor(quantiser * inColor + halfvec) * quantiserDivider;
}

void main(void) {
    // create texture coordinates based on pixelSize //
    vec4 inColor = v_color * (texture2D(u_texture, v_texCoords));
    vec2 entry = mod(gl_FragCoord.xy, vec2(bayerSize, bayerSize));
    int index = int(entry.y) * int(bayerSize) + int(entry.x);
    
    vec4 bayerThreshold = vec4(bayerTex[index] / bayerDivider - 0.5);
    vec4 selvec = nearestColour(inColor + bayerThreshold * quantiserDivider);

    gl_FragColor = selvec * boolean.yyyx + inColor * boolean.xxxy; // use quantised RGB but not the A
}