2d Nebula Shader

I am still a beginner at shading, but I tried to put together something pretty.

Stars rendered using https://godotshaders.com/shader/stars-shader/ by https://godotshaders.com/author/gerardogc2378/

Using FBM on perlin noise to generate clouds, and parallax scrolling through in a circle.

Shader code

shader_type canvas_item;

//uniform vec3 color_replace = vec3(1.0,1.0,0.0);
uniform int OCTAVE = 12;
uniform float timescale = 5.0;
uniform vec4 CLOUD1_COL: hint_color = vec4(0.41,0.64,0.78,0.4);
uniform vec4 CLOUD2_COL: hint_color = vec4(0.99,0.79,0.46,0.2);
uniform vec4 CLOUD3_COL: hint_color = vec4(0.81,0.31,0.59,1.0);
uniform vec4 CLOUD4_COL: hint_color = vec4(0.27,0.15,0.33,1.0);
uniform vec4 SPACE: hint_color = vec4(0.09,0.06,0.28,0.3);
uniform float zoomScale = 6.0;
uniform float size = 10.0;
uniform float starscale = 20.0;
uniform float prob: hint_range(0.0,1.0) = 0.98;

float rand(vec2 input){
	return fract(sin(dot(input,vec2(23.53,44.0)))*42350.45);
}

float perlin(vec2 input){
	vec2 i = floor(input);
	vec2 j = fract(input);
	vec2 coord = smoothstep(0.,1.,j);
	
	float a = rand(i);
	float b = rand(i+vec2(1.0,0.0));
	float c = rand(i+vec2(0.0,1.0));
	float d = rand(i+vec2(1.0,1.0));

	return mix(mix(a,b,coord.x),mix(c,d,coord.x),coord.y);
}

float fbm(vec2 input){
	float value = 0.0;
	float scale = 0.5;
	
	for(int i = 0; i < OCTAVE; i++){
		value += perlin(input)*scale;
		input*=2.0;
		scale*=0.5;
	}
	return value;
}

float fbmCloud(vec2 input, float minimum){
	float value = 0.0;
	float scale = 0.5;
	
	for(int i = 0; i < OCTAVE; i++){
		value += perlin(input)*scale;
		input*=2.0;
		scale*=0.5;
	}
	return smoothstep(0.,1.,(smoothstep(minimum,1.,value)-minimum)/(1.0-minimum));
}

float fbmCloud2(vec2 input, float minimum){
	float value = 0.0;
	float scale = 0.5;
	
	for(int i = 0; i < OCTAVE; i++){
		value += perlin(input)*scale;
		input*=2.0;
		scale*=0.5;
	}
	return (smoothstep(minimum,1.,value)-minimum)/(1.0-minimum);
}

void fragment(){
	vec4 originalColor = texture(TEXTURE, UV);
	float timescaled = TIME * timescale;
	//vec2 zoomUV = vec2(zoomScale * UV.x + UV.x*0.04*TIME*sin(0.07*TIME), zoomScale * UV.y + UV.y*0.05*TIME*cos(0.06*TIME));
	vec2 zoomUV2 = vec2(zoomScale * UV.x + 0.03*timescaled*sin(0.07*timescaled), zoomScale * UV.y + 0.03*timescaled*cos(0.06*timescaled));
	vec2 zoomUV3 = vec2(zoomScale * UV.x + 0.027*timescaled*sin(0.07*timescaled), zoomScale * UV.y + 0.025*timescaled*cos(0.06*timescaled));
	vec2 zoomUV4 = vec2(zoomScale * UV.x + 0.021*timescaled*sin(0.07*timescaled), zoomScale * UV.y + 0.021*timescaled*cos(0.07*timescaled));
	float tide = 0.05*sin(TIME);
	float tide2 = 0.06*cos(0.3*TIME);
	//if(color_replace == originalColor.rgb){
		vec4 nebulaTexture = vec4(SPACE.rgb, 0.5+0.2*sin(0.23*TIME +UV.x-UV.y));
		nebulaTexture += fbmCloud2(zoomUV3, 0.24 + tide)*CLOUD1_COL;
		nebulaTexture += fbmCloud(zoomUV2*0.9, 0.33 - tide)*CLOUD2_COL;
		nebulaTexture = mix(nebulaTexture,CLOUD3_COL,fbmCloud(vec2(0.9*zoomUV4.x,0.9*zoomUV4.y), 0.25+tide2));
		nebulaTexture = mix(nebulaTexture,CLOUD4_COL,fbmCloud(zoomUV3*0.7+2.0, 0.4+tide2));
		vec2 zoomstar = starscale*zoomUV2;
		vec2 pos = floor(zoomstar / size);
		float starValue = rand(pos);
		if(starValue>prob){
			vec2 center = size * pos + vec2(size, size) * 0.5;
			float t = 0.9 + 0.2 * sin(TIME * 8.0 + (starValue - prob) / (1.0 - prob) * 45.0);
			float color = 1.0 - distance(zoomstar, center) / (0.5 * size);
			nebulaTexture = mix(nebulaTexture, vec4(1.0,1.0,1.0,1.0),smoothstep(0.,1.,color * t / (abs(zoomstar.y - center.y)) * t / (abs(zoomstar.x - center.x))));
		} else {
			zoomstar *= 5.0;
			pos = floor(zoomstar / size);
			float starValue2 = rand(pos + vec2(13.0,13.0));
			if(starValue2 >= 0.95){
				vec2 center = size * pos + vec2(size, size) * 0.5;
				float t = 0.9 + 0.2 * sin(TIME * 8.0 + (starValue - prob) / (1.0 - prob) * 45.0);
				float color = 1.0 - distance(zoomstar, center) / (0.5 * size);
				nebulaTexture = mix(nebulaTexture, vec4(1.0,1.0,1.0,1.0),fbmCloud(pos,0.0)*smoothstep(0.,1.,color * t / (abs(zoomstar.y - center.y)) * t / (abs(zoomstar.x - center.x))));
			}
		}
		COLOR = vec4(nebulaTexture.rgb, 1.0);
		//COLOR = vec4(nebulaTexture.rgb,nebulaTexture.a * 1.2)
	//} else {
	//	COLOR = originalColor;
	//}
}

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