enve/examples/shaderEffects/eBrightnessContrast.frag

// enve - 2D animations software
// Copyright (C) 2016-2020 Maurycy Liebner

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// 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 General Public License for more details.

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

#version 330 core
layout(location = 0) out vec4 fragColor;

in vec2 texCoord;

uniform sampler2D texture;
uniform float brightness;
uniform float contrast;

void main(void) {
    vec4 color = texture2D(texture, texCoord);
    fragColor = vec4((color.rgb - 0.5*color.a) * (contrast + 1) + color.a*(0.5 + brightness), color.a);
}