light_mode unshaded;

const highp float c = 0.3;
const highp float alphaModifier = 0.2;
const bool below = true;

void fragment()
{
    highp vec4 tex = zTexture(UV);
    highp float modifier = (UV.y > c ^^ !below) ? 1.0 : alphaModifier;

    COLOR = vec4(tex.x, tex.y, tex.z, tex.w * modifier);
}