Star Nest

This is a shader taken from shadertoy and “translated” to be used in Godot (at least 3.x versions), based on various “branches” of the ‘Star Nest’ by Pablo Andrioli (user “Kali” on Shadertoy). Credits to them.

I’d recommend to be used in a color rect, son of a viewport and grandson of a viewport container with stretch shrink, due to the high processing cost.

In the video I was playing with the variables in order to show the versatility of the shader.
(it was stretched by 5)

I think I’d have a “port” to the Godot 4 versions if needed.

Shader code
shader_type canvas_item;
render_mode unshaded;

uniform int iterations = 20;
uniform float formuparam = 1.00;

uniform int volsteps = 20;
uniform float stepsize = 0.1;

uniform float zoom = 0.800;
uniform float tile = 0.5;
uniform float speed = 0.001;

uniform float brightness = 0.002;
uniform float darkmatter = 0.100;
uniform float distfading = 0.650;
uniform float saturation = 0.750;

uniform vec2 iResolution = vec2(192, 192);
uniform vec2 iMouse = vec2(0,0);

float SCurve (float value) {

    if (value < 0.5)
        return value * value * value * value * value * 16.0; 
    value -= 1.0;
    return value * value * value * value * value * 16.0 + 1.0;

void fragment()
	//get coords and direction
	vec2 uv=FRAGCOORD.xy/iResolution.xy-.5;
	vec3 dir=vec3(uv*zoom,1.);
	float time=TIME*speed+.25;

	//mouse rotation
	float a1=0.5+iMouse.x/iResolution.x*2.;
	float a2=0.8+iMouse.y/iResolution.y*2.;
	mat2 rot1=mat2(vec2(cos(a1),sin(a1)),vec2(-sin(a1),cos(a1)));
	mat2 rot2=mat2(vec2(cos(a2),sin(a2)),vec2(-sin(a2),cos(a2)));
	vec3 from=vec3(1.0,0.5,0.5);
	//volumetric rendering
	float s=0.1,fade=1.;
	vec3 v=vec3(0.);
	for (int r=0; r<volsteps; r++) {
		vec3 p=from+s*dir*0.5;
		p = abs(vec3(tile)-mod(p,vec3(tile*2.))); // tiling fold
		float pa,a=pa=0.;
		for (int i=0; i<iterations; i++) { 
			p=abs(p)/dot(p,p)-formuparam; // the magic formula
			a+=abs(length(p)-pa); // absolute sum of average change
		float dm=max(0.,darkmatter-a*a*.001); //dark matter
		a = pow(a, 2.3); // add contrast
		if (r>6) fade*=1.-dm; // dark matter, don't render near
		v+=vec3(s,s*s,s*s*s*s)*a*brightness*fade; // coloring based on distance
		fade*=distfading; // distance fading
	v=mix(vec3(length(v)),v,saturation); //color adjust
    vec4 C = vec4(v*.01,1.);
     	C.r = pow(C.r, 0.35); 
 	 	C.g = pow(C.g, 0.36); 
 	 	C.b = pow(C.b, 0.38); 
    vec4 L = C;   	
    COLOR.r = mix(L.r, SCurve(C.r), 0.7); 
    COLOR.g = mix(L.g, SCurve(C.g), 1.0); 
    COLOR.b = mix(L.b, SCurve(C.b), 0.2);     	
space, Starnest, Stars
The shader code and all code snippets in this post are under MIT license and can be used freely. Images and videos, and assets depicted in those, do not fall under this license. For more info, see our License terms.

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1 month ago

Would you by any chance have any ideas of fixing the very small flickering stars from this shader, I’ve been trying but with no luck.