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bayer-dithering shader revisited

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minjaesong
2017-07-15 18:35:57 +09:00
parent 1f0608b768
commit 9f56ca2e99
4 changed files with 54 additions and 49 deletions
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83
assets/4096_bayer.frag
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@@ -4,56 +4,53 @@ uniform sampler2D u_texture;
uniform mat4 Bayer;
uniform float monitorGamma;
//uniform mat4 bayer;
uniform float monitorGamma; // give 2.2f
vec4 gammaIn(vec4 col) {
return pow(col, vec4(vec3(monitorGamma), 1.0));
}
int bayer[8][8] = {
{ 0, 32, 8, 40, 2, 34, 10, 42}, // 8x8 bayer ordered dithering
{48, 16, 56, 24, 50, 18, 58, 26}, // pattern. Each input pixel
{12, 44, 4, 36, 14, 46, 6, 38}, // is scaled to the 0..63 range
{60, 28, 52, 20, 62, 30, 54, 22}, // before looking in this table
{ 3, 35, 11, 43, 1, 33, 9, 41}, // to determine the action
{51, 19, 59, 27, 49, 17, 57, 25},
{15, 47, 7, 39, 13, 45, 5, 37},
{63, 31, 55, 23, 61, 29, 53, 21} }; // fun fact: you can calculate bayer value on-the-fly but LUT is faster
float bayerSize = 8.0;
float bayerDivider = bayerSize * bayerSize;
vec4 gammaOut(vec4 col) {
return pow(col, vec4(vec3(1.0 / monitorGamma), 1.0));
vec4 nearestColour(vec4 incolor) {
vec4 rgbaCounts = vec4(16.0, 16.0, 16.0, 1.0);
vec4 color = incolor;
color.r = floor((rgbaCounts.r - 1.0) * color.r + 0.5) / (rgbaCounts.r - 1.0);
color.g = floor((rgbaCounts.g - 1.0) * color.g + 0.5) / (rgbaCounts.g - 1.0);
color.b = floor((rgbaCounts.b - 1.0) * color.b + 0.5) / (rgbaCounts.b - 1.0);
if (rgbaCounts.a >= 2.0) {
color.a = floor((rgbaCounts.a - 1.0) * color.a + 0.5) / (rgbaCounts.a - 1.0);
}
else if (rgbaCounts.a == 1.0) {
color.a = (color.a >= 0.5f) ? 1.0 : 0.0;
}
else {
color.a = 1.0;
}
return color;
}
void main(void) {
// create texture coordinates based on pixelSize //
float pixelSize = 1.0;
vec4 inColor = texture2D(u_texture, v_texCoords);
vec2 pixelSizeVec = vec2(float(pixelSize), float(pixelSize));
vec2 entry = mod(gl_FragCoord.xy, vec2(bayerSize, bayerSize));
vec2 discrete = (gl_FragCoord.xy + 0.001) / v_texCoords / pixelSizeVec;
//vec2 discrete = (gl_FragCoord.xy) / v_texCoords / pixelSizeVec;
float r = 1.0 / monitorGamma;
discrete = floor(discrete * v_texCoords) / discrete;
vec4 color = texture2D(u_texture, discrete).rgba;
// add Bayer matrix entry to current pixel //
vec2 entry = mod(gl_FragCoord.xy / pixelSizeVec, vec2(4, 4));
color.r = color.r + Bayer[int(entry.x)][int(entry.y)] / 17.0 - 0.5;
color.g = color.g + Bayer[int(entry.x)][int(entry.y)] / 17.0 - 0.5;
color.b = color.b + Bayer[int(entry.x)][int(entry.y)] / 17.0 - 0.5;
//color.a = color.a + Bayer[int(entry.x)][int(entry.y)] / 17.0 - 0.5;
// find nearest 8-bit color //
color.r = floor(15.0 * color.r + 0.5) / 15.0;
color.g = floor(15.0 * color.g + 0.5) / 15.0;
color.b = floor(15.0 * color.b + 0.5) / 15.0;
//color.a = floor(15.0 * color.a + 0.5) / 15.0;
gl_FragColor = color;
//vec4 color = texture2D(u_texture, v_texCoords);
//color = floor(15.0 * color + 0.5) / 15.0;
//
//gl_FragColor = color;
gl_FragColor = nearestColour(inColor + r * (bayer[int(entry.y)][int(entry.x)] / bayerDivider - 0.5));
//gl_FragColor = nearestColour(inColor);
}