add fog update based on day

core/daynight/fog.gdshader

@@ -7,6 +7,7 @@ uniform bool use_red_as_alpha = true;
 
 group_uniforms Settings;
 uniform vec4 fog_color : source_color = vec4(0.8, 0.85, 0.9, 0.5);
+uniform float fog_density : hint_range(0.0, 1.0) = 0.25;
 uniform vec2 scroll_speed = vec2(0.05, 0.01);
 uniform vec2 texture_scale = vec2(1.0, 1.0);
 
@@ -36,5 +37,5 @@ void fragment() {
 	vec3 dark_fog = tinted_fog * 0.5;
 	ALBEDO = mix(tinted_fog, dark_fog, night_intensity);
 	
-	ALPHA = fog_color.a * noise_alpha * edge_mask;
-}
+	ALPHA = fog_color.a * fog_density * noise_alpha * edge_mask;
+}