#version 120

/*
 Copyright (C) 2010-2017 Kristian Duske
 
 This file is part of TrenchBroom.
 
 TrenchBroom 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.
 
 TrenchBroom 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 TrenchBroom. If not, see <http://www.gnu.org/licenses/>.
 */

uniform float Brightness;
uniform sampler2D Texture;
uniform bool ApplyTinting;
uniform vec4 TintColor;
uniform bool GrayScale;

void main() {
    vec4 texel = texture2D(Texture, gl_TexCoord[0].st);

    // Assume alpha masked or opaque.
    // TODO: Make this optional if we gain support for translucent textures
    if (texel.a < 0.5) {
        discard;
    }

    gl_FragColor = vec4(vec3(Brightness / 2.0 * texel), texel.a);
    gl_FragColor = clamp(2 * gl_FragColor, 0.0, 1.0);
    
    if (GrayScale) {
        float gray = dot(gl_FragColor.rgb, vec3(0.299, 0.587, 0.114));
        gl_FragColor = vec4(gray, gray, gray, gl_FragColor.a);
    }
    
    if (ApplyTinting) {
        gl_FragColor = vec4(gl_FragColor.rgb * TintColor.rgb * TintColor.a, gl_FragColor.a);
        gl_FragColor = clamp(2.0 * gl_FragColor, 0.0, 1.0);
    }
}