Files
Terrarum/src/shaders/postproc_dither.frag
2023-02-28 17:32:52 +09:00

88 lines
2.1 KiB
GLSL

/**
* Blue Noise texture created by Christoph Peters, released under CC0
* http://momentsingraphics.de/BlueNoise.html
*/
#version 150
#ifdef GL_ES
precision mediump float;
#endif
vec4 gammaIn(vec4 col) {
return pow(col, vec4(2.2));
}
vec4 gammaOut(vec4 col) {
return pow(col, vec4(1.0 / 2.2));
}
in vec4 v_color; // unused!
in vec2 v_texCoords;
uniform sampler2D u_texture;
uniform sampler2D u_pattern;
uniform ivec2 rnd = ivec2(0,0);
uniform mat4 swizzler = mat4(
1.0,0.0,0.0,0.0,
0.0,1.0,0.0,0.0,
0.0,0.0,1.0,0.0,
0.0,0.0,0.0,1.0
);
uniform float quant = 255.0; // 64 steps -> 63.0; 256 steps -> 255.0
out vec4 fragColor;
vec2 boolean = vec2(0.0, 1.0);
vec4 matrixNormaliser = vec4(0.5 / 256.0);
vec2 patternsize = vec2(1.0/512.0, 1.0/512.0);
mat4 rgb_to_ycocg = mat4(
0.25, 1.0, -0.5, 0.0,
0.5, 0.0, 1.0, 0.0,
0.25, -1.0, -0.5, 0.0,
0.0, 0.0, 0.0, 1.0
);
mat4 ycocg_to_rgb = mat4(
1.0, 1.0, 1.0, 0.0,
0.5, 0.0, -0.5, 0.0,
-0.5, 0.5, -0.5, 0.0,
0.0, 0.0, 0.0, 1.0
);
vec4 nearestColour(vec4 inColor) {
return floor(vec4(quant) * inColor) * vec4(1.0 / quant);
}
vec4 getDitherredDot(vec4 inColor) {
vec4 bayerThreshold = swizzler * vec4(matrixNormaliser + texture(u_pattern, (gl_FragCoord.xy + rnd) * patternsize));
return nearestColour(bayerThreshold * vec4(1.0 / quant) + inColor);
}
uniform vec4 vibrancy = vec4(1.0);//vec4(1.0, 1.4, 1.2, 1.0);
void main(void) {
// convert input RGB into YCoCg
vec4 incolour = texture(u_texture, v_texCoords);
vec4 yog = rgb_to_ycocg * incolour; // vec4(Y, Co, Cg, A) where Y,A=[0,1]; Co,Cg=[-1,1]
// Do colour-grading magic
vec4 sgn = sign(yog);
vec4 absval = abs(yog);
vec4 raised = pow(absval, boolean.yyyy / vibrancy);
vec4 newColour = sgn * raised;
// Dither the output
vec4 graded = ycocg_to_rgb * newColour;
vec4 selvec = getDitherredDot(graded);
vec4 outcol = selvec * boolean.yyyx + boolean.xxxy; // use quantised RGB but not the A
fragColor = outcol;
// ivec4 bytes = ivec4(255.0 * outcol);
// ivec4 mask = ivec4(0x55);
// fragColor = (bytes ^ mask) / 255.0;
}