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shaders/2D/indexed/indexed_dist.glsl

87 lines
2.6 KiB

#iChannel0 "file://./Textures/colorful.jpg"
#iChannel0::WrapMode "Mirror"
float pow2(float x) {
return x*x;
}
/* euclidian */
float colDist(vec3 col1, vec3 col2) {
return distance(col1, col2);
}
/* optimized L*a*b*-like */
float colDist2(vec3 col1, vec3 col2) {
float r_mean = (col1.r + col2.r) * 256./2.0;
float r = (col1.r - col2.r) * 256.;
float g = (col1.g - col2.g) * 256.;
float b = (col1.b - col2.b) * 256.;
//float dc = sqrt((2.0+r_mean/256.) * pow2(r)
// + 4.0*pow2(g)
// + (2.0 + (255.-r_mean)/256.) * pow2(b) );
float dc = sqrt( (512.+r_mean)*r*r/256.
+ 4.*g*g +
(767.-r_mean)*b*b/256.);
return dc;
}
vec3 bestColor(vec3 col, vec3 pal[22]) {
//col = pow(col, vec3(1./2.2));
//col.r = pow(col.r,1./1.7);
//col.g = pow(col.g,1./1.7);
//col.b = pow(col.b,1./2.2);
float mdist = colDist2(col, pal[0]);
vec3 bcolor = pal[0];
for(int i=0;i<22;i++) {
float d = colDist2(col, pal[i]);
if (d < mdist ) {
mdist = d;
bcolor = pal[i];
}
}
return bcolor;
}
void mainImage ( out vec4 fragColor, in vec2 fragCoord) {
vec3 pal[22];
pal[0]=vec3(0.953125,0.953125,0.953125);
pal[1] = vec3(0.578125,0.6875,0.7578125);
pal[2] = vec3(0.3359375,0.421875,0.5234375);
pal[3] = vec3(0.19921875,0.234375,0.33984375);
pal[4] = vec3(0.1015625,0.109375,0.171875);
pal[5] = vec3(0.99609375,0.80078125,0.45703125);
pal[6] = vec3(0.93359375,0.48828125,0.33984375);
pal[7] = vec3(0.55859375,0.3359375,0.23046875);
pal[8] = vec3(0.3984375,0.22265625,0.19140625);
pal[9] = vec3(0.65234375,0.9375,0.4375);
pal[10] = vec3(0.21875,0.71484375,0.390625);
pal[11] = vec3(0.14453125,0.44140625,0.47265625);
pal[12] = vec3(0.84765625,0.33984375,0.38671875);
pal[13] = vec3(0.921875,0.19921875,0.296875);
pal[14] = vec3(0.69140625,0.2421875,0.32421875);
pal[15] = vec3(0.4609375,0.2578125,0.5390625);
pal[16] = vec3(0.36328125,0.15234375,0.36328125);
pal[17] = vec3(0.26953125,0.15625,0.234375);
pal[18] = vec3(0.5859375,0.78125,0.93359375);
pal[19] = vec3(0.25390625,0.6484375,0.9609375);
pal[20] = vec3(0.23046875,0.36328125,0.78515625);
pal[21] = vec3(0.24609375,0.24609375,0.453125);
vec2 uv = (fragCoord/iResolution.y);
vec4 col = vec4(0,0,0,1.0);
vec3 texCol = texture(iChannel0, uv).rgb;
vec3 tmp = bestColor( texCol, pal);
col.rgb = tmp;
fragColor = col;
}