uniform sampler2D tex;

out vec4 FragColor;

vec3 getCIEYxy(vec3 rgbColor);
vec3 getRGBFromCIEXxy(vec3 YxyColor);

void main()
{
    vec2 uv = gl_FragCoord.xy / 512;
    vec3 col = texture(tex, uv).xyz;
    vec3 Yxy = getCIEYxy(col);
    vec3 WhiteYxy = getCIEYxy(vec3(1.));

    Yxy.x = smoothstep(WhiteYxy.x, WhiteYxy.x * 4, Yxy.x);

    FragColor = vec4(max(vec3(0.), getRGBFromCIEXxy(Yxy)), 1.0);
}