#version 330 core

in vec3 frag_position;
in vec3 frag_normal;
in vec2 frag_uv;

uniform sampler2D u_texture;

uniform vec3 u_color = vec3(1, 1, 1);
uniform vec3 u_light_direction = vec3(-1, 3, -2);

out vec4 FragColor;

void main()
{
    // Sample texture
    vec4 tex_color = texture(u_texture, frag_uv);

    // Face normal
    vec3 normal = normalize(frag_normal);

    // Directional lighting
    vec3 light_direction = normalize(u_light_direction);
    float diffuse = max(dot(normal, light_direction), 0.0);

    // Ambient + diffuse
    float ambient = 0.25;
    float lighting = ambient + diffuse * 0.75;

    // Final color
    vec3 color = tex_color.rgb * u_color * lighting;

    FragColor = vec4(color, tex_color.a);
}