/** 
 * @file pbrglowF.glsl
 *
 * $LicenseInfo:firstyear=2023&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2023, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

/*[EXTRA_CODE_HERE]*/

// forward fullbright implementation for HUDs

uniform sampler2D diffuseMap;  //always in sRGB space

uniform vec3 emissiveColor;
uniform sampler2D emissiveMap;

out vec4 frag_color;

in vec3 vary_position;
in vec4 vertex_emissive;

in vec2 base_color_texcoord;
in vec2 emissive_texcoord;

uniform float minimum_alpha; // PBR alphaMode: MASK, See: mAlphaCutoff, setAlphaCutoff()

vec3 linear_to_srgb(vec3 c);
vec3 srgb_to_linear(vec3 c);

void main()
{
    vec4 basecolor = texture(diffuseMap, base_color_texcoord.xy).rgba;

    if (basecolor.a < minimum_alpha)
    {
        discard;
    }

    vec3 emissive = emissiveColor;
    emissive *= srgb_to_linear(texture(emissiveMap, emissive_texcoord.xy).rgb);

    float lum = max(max(emissive.r, emissive.g), emissive.b);
    lum *= vertex_emissive.a;

    // HUDs are rendered after gamma correction, output in sRGB space
    frag_color.rgb = vec3(0);
    frag_color.a = lum;
}