#version 330

in vec2 fragTexCoord;
in vec4 fragColor;
in vec3 fragPosition;
in vec3 fragNormal;

uniform sampler2D texture0;
uniform vec4 sunlightColor;

uniform vec3 lightDir;

out vec4 finalColor;

void main()
{
    vec4 texelColor = texture(texture0, fragTexCoord);

    vec3 N = normalize(fragNormal);
    vec3 L = normalize(lightDir);

    float ndotl = max(dot(N, L), 0.0);
    float ambient = 0.1;
    float sunfactor = ambient + (1.0 - ambient) * ndotl;

    sunfactor *= 1+min(0, L.y);
    vec3 Lmoon = normalize(-lightDir);
    float ndotlMoon = max(dot(N, Lmoon), 0.0);
    float moonfactor = (ambient + (1.0 - ambient) * ndotlMoon) * 8;
    moonfactor *= max(0, -L.y);

    // In fragColor, 'r' is blocklight R, 'g' is blocklight G, 'b' is blocklight B and 'a' is sunlight
    texelColor.r *= fragColor.a * sunlightColor.r * (sunfactor+moonfactor) + fragColor.r;
    texelColor.g *= fragColor.a * sunlightColor.g * (sunfactor+moonfactor) + fragColor.g;
    texelColor.b *= fragColor.a * sunlightColor.b * (sunfactor+moonfactor) + fragColor.b;
    finalColor = texelColor;
}