grayscale filter

[zoovasoup]

hey, nice project you have here!

i think its nice to have grayscale filter and the ability to enable multiple filter at the same time, like enabling grayscale and blue-light filter

personaly i would love to have this feature

[loqusion]

I've put together a grayscale shader:

precision highp float;
varying vec2 v_texcoord;
uniform sampler2D tex;

const int LUMINOSITY = 0;
const int LIGHTNESS = 1;
const int AVERAGE = 2;

const int Type = {{#nc}}{{type}} ? LUMINOSITY{{/nc}};

const int PAL = 0;
const int HDTV = 1;
const int HDR = 2;

const int LuminosityType = {{#nc}}{{luminosity_type}} ? HDR{{/nc}};

void main() {
    vec4 pixColor = texture2D(tex, v_texcoord);

    float gray;
    if (Type == LUMINOSITY) {
        // https://en.wikipedia.org/wiki/Grayscale#Luma_coding_in_video_systems
        if (LuminosityType == 0) {
            gray = dot(pixColor.rgb, vec3(0.299, 0.587, 0.114));
        } else if (LuminosityType == 1) {
            gray = dot(pixColor.rgb, vec3(0.2126, 0.7152, 0.0722));
        } else if (LuminosityType == 2) {
            gray = dot(pixColor.rgb, vec3(0.2627, 0.6780, 0.0593));
        }
    } else if (Type == LIGHTNESS) {
        float maxPixColor = max(pixColor.r, max(pixColor.g, pixColor.b));
        float minPixColor = min(pixColor.r, min(pixColor.g, pixColor.b));
        gray = (maxPixColor + minPixColor) / 2.0;
    } else if (Type == AVERAGE) {
        gray = (pixColor.r + pixColor.g + pixColor.b) / 3.0;
    }

    vec3 grayscale = vec3(gray);
    gl_FragColor = vec4(grayscale, pixColor.a);
}

// vim: ft=glsl

You can try it out from the development branch by saving it to grayscale.glsl.mustache and running hyprshade on ./grayscale.glsl.mustache --var type=<TYPE>.

Alternatively, if you're using 3.x:

precision highp float;
varying vec2 v_texcoord;
uniform sampler2D tex;

const int LUMINOSITY = 0;
const int LIGHTNESS = 1;
const int AVERAGE = 2;

const int Type = LUMINOSITY;

const int PAL = 0;
const int HDTV = 1;
const int HDR = 2;

const int LuminosityType = HDR;

void main() {
    vec4 pixColor = texture2D(tex, v_texcoord);

    float gray;
    if (Type == LUMINOSITY) {
        // https://en.wikipedia.org/wiki/Grayscale#Luma_coding_in_video_systems
        if (LuminosityType == 0) {
            gray = dot(pixColor.rgb, vec3(0.299, 0.587, 0.114));
        } else if (LuminosityType == 1) {
            gray = dot(pixColor.rgb, vec3(0.2126, 0.7152, 0.0722));
        } else if (LuminosityType == 2) {
            gray = dot(pixColor.rgb, vec3(0.2627, 0.6780, 0.0593));
        }
    } else if (Type == LIGHTNESS) {
        float maxPixColor = max(pixColor.r, max(pixColor.g, pixColor.b));
        float minPixColor = min(pixColor.r, min(pixColor.g, pixColor.b));
        gray = (maxPixColor + minPixColor) / 2.0;
    } else if (Type == AVERAGE) {
        gray = (pixColor.r + pixColor.g + pixColor.b) / 3.0;
    }

    vec3 grayscale = vec3(gray);
    gl_FragColor = vec4(grayscale, pixColor.a);
}

Save it to grayscale.glsl and adjust the Type and LuminosityType to your liking, then run hyprshade on ./grayscale.glsl.

I'll definitely add this shader to the 4.0.0 release.

[loqusion]

Added in 0c14891

[zoovasoup]

it works!! thank you for making it