client/menu/grayscale.gdshader


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/*
    Hurry Curry! - a game about cooking
    Copyright 2024 nokoe

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published by
    the Free Software Foundation, version 3 of the License only.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.

*/
shader_type canvas_item;

void fragment() {
    float brightness = 0.2126 * COLOR.r + 0.7152 * COLOR.g + 0.0722 * COLOR.b;
    brightness = (brightness - .5) * 2.;
    COLOR.rgb = vec3(brightness);
    COLOR.a *= 1. - brightness;
}