From 3c00e990dc488b0c694d0fd331e661255d927faa Mon Sep 17 00:00:00 2001 From: gizmo98 Date: Wed, 17 May 2023 15:44:30 +0200 Subject: [PATCH] add bayer 4x4 matrix ordered grid dithering shader Features: - uses bayer 4x4 matrix - color depth can be selected with a parameter - dithering will be calculated according to selected color depth --- dithering/bayer_4x4.slangp | 10 ++ dithering/shaders/bayer_4x4.slang | 214 ++++++++++++++++++++++++++++++ 2 files changed, 224 insertions(+) create mode 100644 dithering/bayer_4x4.slangp create mode 100644 dithering/shaders/bayer_4x4.slang diff --git a/dithering/bayer_4x4.slangp b/dithering/bayer_4x4.slangp new file mode 100644 index 0000000..c5ced22 --- /dev/null +++ b/dithering/bayer_4x4.slangp @@ -0,0 +1,10 @@ +shaders = "1" +shader0 = "shaders/bayer_4x4.slang" +filter_linear0 = "false" +scale_type0 = viewport + +parameters = "COLOR_DEPTH;DITHER_TUNE;EGA_PALETTE" +COLOR_DEPTH = "2.0" +DITHER_TUNE = "0.0" +EGA_PALETTE = "0.0" + diff --git a/dithering/shaders/bayer_4x4.slang b/dithering/shaders/bayer_4x4.slang new file mode 100644 index 0000000..09d49d1 --- /dev/null +++ b/dithering/shaders/bayer_4x4.slang @@ -0,0 +1,214 @@ +#version 450 +/* + * gizmo98 bayer 4x4 dithering shader + * Copyright (C) 2023 gizmo98 + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + * + * version 0.1, 16.05.2023 + * --------------------------------------------------------------------------------------- + * - initial commit + * + * https://github.com/gizmo98/gizmo-crt-shader + * + * uses parts of texture anti-aliasing shader from Ikaros https://www.shadertoy.com/view/ldsSRX + */ + +layout(push_constant) uniform Push +{ + vec4 SourceSize; + vec4 OriginalSize; + vec4 OutputSize; + uint FrameCount; + float COLOR_DEPTH; + float DITHER_TUNE; + float EGA_PALETTE; +} params; + +layout(std140, set = 0, binding = 0) uniform UBO +{ + mat4 MVP; +} global; + +#pragma parameter COLOR_DEPTH "Color depth in Bits" 1.0 1.0 8.0 1.0 +#pragma parameter DITHER_TUNE "Tune dithering" 0.0 -64.0 64.0 1.0 +#pragma parameter EGA_PALETTE "EGA palette" 0.0 0.0 1.0 1.0 + +#pragma stage vertex +layout(location = 0) in vec4 Position; +layout(location = 1) in vec2 TexCoord; +layout(location = 0) out vec2 vTexCoord; + +void main() +{ + gl_Position = global.MVP * Position; + vTexCoord = TexCoord; +} + +#pragma stage fragment +layout(location = 0) in vec2 vTexCoord; +layout(location = 0) out vec4 FragColor; +layout(set = 0, binding = 2) uniform sampler2D Source; + +vec4 DitherPattern(vec4 col, vec2 coord) +{ + mat4 bayerMatrix; + bayerMatrix[0] = vec4(0.0, 8.0, 2.0, 10.0); + bayerMatrix[1] = vec4(12.0, 4.0, 14.0, 6.0); + bayerMatrix[2] = vec4(3.0, 11.0, 1.0, 9.0); + bayerMatrix[3] = vec4(15.0, 7.0, 13.0, 5.0); + + ivec2 st = ivec2(fract(coord.xy / 4.0) * 4.0); + float threshold = bayerMatrix[st.x][st.y]; + float multiplier = pow(2.0,8.0 - params.COLOR_DEPTH) - 1.0; + + threshold = (threshold / 15.0) - 0.5; + threshold *= ((multiplier + params.DITHER_TUNE) / 255.0); + + col.rgb += threshold; + return col; +} + +vec2 saturateA(in vec2 x) +{ + return clamp(x, 0.0, 1.0); +} + +vec2 magnify(in vec2 uv, in vec2 res) +{ + uv *= res; + return (saturateA(fract(uv) / saturateA(fwidth(uv))) + floor(uv) - 0.5) / res.xy; +} +vec4 textureAA(in vec2 uv){ + vec2 texSize = vec2(textureSize(Source, 0)); + uv = magnify(uv,texSize.xy); + vec2 uv1 = uv*texSize.xy; + + vec2 iuv = floor(uv1); + vec4 col = texture( Source, uv ); + + col = DitherPattern( col , iuv - 0.5); + return col; +} + +vec4 ColorDepthReduction(vec4 col) +{ + float divider = pow(2.0,params.COLOR_DEPTH) - 1.0; + col.rgb *= divider; + col.rgb = floor(col.rgb) + step(0.5, fract(col.rgb)); + col.rgb /= divider; + return col; +} + +vec4 EGAPalette(vec4 col) +{ + float divider = 3.0; + vec3 c = floor(col.rgb * divider) + step(0.5, fract(col.rgb * divider)); + if (c.rgb == vec3(0.0,0.0,0.0) || + c.rgb == vec3(1.0,1.0,1.0) || + c.rgb == vec3(2.0,2.0,2.0) || + c.rgb == vec3(3.0,3.0,3.0) || + c.rgb == vec3(2.0,1.0,0.0)) + col.rgb = col.rgb; + // bright green + else if (c.rgb == vec3(0.0,3.0,0.0)|| + c.rgb == vec3(0.0,3.0,2.0)|| + c.rgb == vec3(2.0,3.0,0.0)|| + c.rgb == vec3(0.0,3.0,1.0)|| + c.rgb == vec3(1.0,3.0,1.0)|| + c.rgb == vec3(1.0,3.0,0.0)|| + c.rgb == vec3(2.0,3.0,1.0)|| + c.rgb == vec3(2.0,3.0,2.0)) + col.rgb = vec3(1.0,3.0,1.0) / divider; + // green + else if (c.rgb == vec3(0.0,2.0,0.0)|| + c.rgb == vec3(0.0,2.0,1.0)|| + c.rgb == vec3(0.0,1.0,0.0)|| + c.rgb == vec3(0.0,1.0,1.0)|| + c.rgb == vec3(1.0,2.0,1.0)|| + c.rgb == vec3(1.0,2.0,0.0)|| + c.rgb == vec3(0.0,1.0,1.0)) + col.rgb = vec3(0.0,2.0,0.0) / divider; + // bright red + else if (c.rgb == vec3(3.0,0.0,0.0)|| + c.rgb == vec3(3.0,0.0,1.0)|| + c.rgb == vec3(3.0,1.0,0.0)|| + c.rgb == vec3(3.0,1.0,1.0)) + col.rgb = vec3(3.0,1.0,1.0) / divider; + // red + else if (c.rgb == vec3(2.0,0.0,0.0)|| + c.rgb == vec3(2.0,0.0,1.0)|| + c.rgb == vec3(1.0,0.0,0.0)) + col.rgb = vec3(2.0,0.0,0.0) / divider; + // bright cyan + else if (c.rgb == vec3(0.0,3.0,3.0)|| + c.rgb == vec3(1.0,3.0,3.0)|| + c.rgb == vec3(2.0,3.0,3.0)) + col.rgb = vec3(1.0,3.0,3.0) / divider; + // cyan + else if (c.rgb == vec3(0.0,2.0,2.0)|| + c.rgb == vec3(1.0,2.0,2.0)) + col.rgb = vec3(0.0,2.0,2.0) / divider; + // bright blue + else if (c.rgb == vec3(0.0,2.0,3.0)|| + c.rgb == vec3(1.0,2.0,3.0)|| + c.rgb == vec3(0.0,0.0,3.0)) + col.rgb = vec3(1.0,1.0,3.0) / divider; + // blue + else if (c.rgb == vec3(0.0,0.0,2.0)|| + c.rgb == vec3(0.0,0.0,1.0)|| + c.rgb == vec3(0.0,1.0,2.0)|| + c.rgb == vec3(1.0,1.0,3.0)|| + c.rgb == vec3(0.0,1.0,3.0)) + col.rgb = vec3(0.0,0.0,2.0) / divider; + // brown + else if (c.rgb == vec3(2.0,1.0,0.0)|| + c.rgb == vec3(2.0,1.0,1.0)|| + c.rgb == vec3(1.0,1.0,0.0)) + col.rgb = vec3(2.0,1.0,0.0) / divider; + // bright yellow + else if (c.rgb == vec3(3.0,3.0,0.0)|| + c.rgb == vec3(3.0,3.0,1.0)|| + c.rgb == vec3(3.0,3.0,2.0)|| + c.rgb == vec3(2.0,2.0,0.0)|| + c.rgb == vec3(2.0,2.0,1.0)) + col.rgb = vec3(3.0,3.0,1.0) / divider; + // magenta + else if (c.rgb == vec3(2.0,0.0,2.0)|| + c.rgb == vec3(2.0,0.0,3.0)|| + c.rgb == vec3(2.0,1.0,2.0)|| + c.rgb == vec3(2.0,1.0,3.0)) + col.rgb = vec3(2.0,0.0,2.0) / divider; + // bright magenta + else if (c.rgb == vec3(3.0,0.0,2.0)|| + c.rgb == vec3(3.0,0.0,3.0)|| + c.rgb == vec3(3.0,2.0,3.0)|| + c.rgb == vec3(3.0,1.0,3.0)|| + c.rgb == vec3(3.0,1.0,2.0)) + col.rgb = vec3(3.0,1.0,3.0) / divider; + else if (c.r == 0.0) + col.gb = step(2.0,c.gb) * 2.0 / divider; + else if (c.g == 0.0) + col.rb = step(2.0,c.rb) * 2.0 / divider; + else if (c.b == 0.0) + col.rg = step(2.0,c.rg) * 2.0 / divider; + else if (c.r == 3.0) + col.gb = step(1.0,c.gb) / divider; + else if (c.g == 3.0) + col.rb = step(1.0,c.rb) / divider; + else if (c.b == 3.0) + col.rg = step(1.0,c.rg) / divider; + return col; +} + +void main() +{ + vec2 texcoord = vTexCoord.xy; + FragColor = textureAA(texcoord); + FragColor = ColorDepthReduction(FragColor); + if (params.EGA_PALETTE == 1.0) + FragColor = EGAPalette(FragColor); +}