#version 330 core

uniform vec3 sky_color;
uniform vec3 sun_direction;

in vec3 surface_normal;
in float depth;
out vec4 color;

void main() {
    float brightness = dot(normalize(surface_normal), normalize(-sun_direction));
    vec3 diffuse = vec3(1 - clamp(brightness, -0.3, 0.2));
    vec3 base = vec3(1.0, 1.0, 1.0) * diffuse;

    color = vec4(mix(sky_color, base, 1 - depth), 0.3);
}