shader_type spatial;
render_mode blend_add, specular_disabled, ambient_light_disabled;

/*
noise1 = universe_noise.rg
noise2 = universe_noise.ba
*/
uniform sampler2D universe_noise;
/*
stars = other_noise.r
star_noise = other_noise.g
gradient = other_noise.b
*/
uniform vec2 displace_gradient = vec2(0.0);
uniform vec2 displace_stars = vec2(0.0);
uniform float star_scale = 0.5;
uniform sampler2D other_noise;
uniform vec4 fog_color:hint_color = vec4(0.0, 0.0, 1.0, 1.0);
uniform vec4 star_color:hint_color = vec4(1.0);
uniform float strengh_noise1 = 3.0;
uniform float strengh_noise2 = 3.0;
uniform float strengh_star_noise = 0.5;
uniform float time_scale_noise1 = 0.05;
uniform float time_scale_noise2 = 0.05;
uniform float time_scale_stars = 0.05;
uniform float time_scale_star_noise = 0.2;

// https://gist.github.com/ayamflow/c06bc0c8a64f985dd431bd0ac5b557cd
vec2 rotateUV(vec2 uv, vec2 mid, float rotation)
{
    return vec2(
      cos(rotation) * (uv.x - mid.x) + sin(rotation) * (uv.y - mid.y) + mid.x,
      cos(rotation) * (uv.y - mid.y) - sin(rotation) * (uv.x - mid.x) + mid.y
    );
}

void fragment() {
    ALBEDO = vec3(0.0);
    ALBEDO = fog_color.rgb * texture(other_noise, displace_gradient + UV +
        (
            texture(universe_noise, rotateUV(UV, vec2(0.0, 0.0), TIME * time_scale_noise1)).rg
            - vec2(.5)
        )
        * strengh_noise1
        + (
            texture(universe_noise, rotateUV(UV, vec2(1.0, 1.0), TIME * time_scale_noise2)).ba
            - vec2(.5)
        )
        * strengh_noise2
    ).b
    + (star_color.rgb * (texture(other_noise, rotateUV(UV, vec2(0.0, 0.0), TIME * time_scale_noise2) ).r
        * max(0.0, sin(
            TIME * time_scale_star_noise
            * texture(other_noise, UV).g
        ))));
}