// Grayscale.
//
// Panama's accessibility color filters. Selected by the `colorFilter`
// preference; hypr/looks.lua maps the enum to this path at config time and
// services/SystemSettings.qml does the same live.
//
// Hyprland runs one fragment shader over the finished frame, so this covers
// every window, the shell, video and the cursor alike.
//
// Rec. 709 luminance weights -- the same ones an SVG <feColorMatrix
// type="saturate" values="0"> uses. A flat average would make reds and blues
// far too bright and greens far too dark, because the eye does not weigh the
// channels equally.

#version 300 es

precision mediump float;
in vec2 v_texcoord;
layout(location = 0) out vec4 fragColor;
uniform sampler2D tex;

void main() {
    vec4 pixColor = texture(tex, v_texcoord);

    float luminance = dot(pixColor.rgb, vec3(0.2126, 0.7152, 0.0722));

    fragColor = vec4(vec3(luminance), pixColor.a);
}