/**
 * QUIK: User Interface Kit
 * Copyright (C) 2023 Halit Utku Maden, et al.
 */
#version 120

varying vec2        fv2TexPos;
varying vec4        fv4Color;

uniform int         iEnableSdf;
uniform int         iEnableTexture;
uniform int         iAlphaDiscard;
uniform float       fSdfThreshold;
uniform sampler2D   txTexture;

void main(void)
{
    vec4 albedo = fv4Color;

    if (iEnableTexture != 0)
    {
        vec4 value = texture2D(txTexture, fv2TexPos);

        if (iEnableSdf != 0)
        {
            float a = max(value.r, value.a);

            value = (a >= fSdfThreshold) ? vec4(1,1,1,1) : vec4(0,0,0,0);
        }

        if (iAlphaDiscard != 0 && value.a == 0.0)
        {
            discard;
        }

        albedo = albedo * value;
    }

    gl_FragColor = albedo;
}