Thank you Kali!

Option 2D of

https://www.shadertoy.com/view/XlfGRj.

#include "Progressive2D.frag"

uniform float time;

vec3 iResolution = vec3(1.0/pixelSize.x, 1.0/pixelSize.y, 1.0);

uniform vec3 iMouse; slider[(-720,-720,0),(0,0,0),(720,720,1)]

float iGlobalTime = time;

// Star Nest by Pablo Román Andrioli

// This content is under the MIT License.

uniform int iterations; slider[0,17,50]

uniform float formuparam; slider[0,0.53,1]

uniform float volsteps; slider[0,20,40]

uniform float stepsize; slider[0,0.1,0.15]

uniform float zoom; slider[0,0.8,5]

uniform float tile; slider[0,0.850,1]

uniform float speed; slider[0,0.01,0.1]

uniform float brightness; slider[0,0.0015,0.01]

uniform float darkmatter; slider[0,0.3,1]

uniform float distfading; slider[0,0.730,1]

uniform float saturation; slider[0,0.850,1]

vec3 color(vec2 J)

{

//get coords and direction

vec2 uv=J.xy/iResolution.xy;

uv.y*=iResolution.y/iResolution.x;

vec3 dir=vec3(uv*zoom,1.);

float time=iGlobalTime*speed+.25;

//mouse rotation

float a1=.5+iMouse.x/iResolution.x*2.;

float a2=.8+iMouse.y/iResolution.y*2.;

mat2 rot1=mat2(cos(a1),sin(a1),-sin(a1),cos(a1));

mat2 rot2=mat2(cos(a2),sin(a2),-sin(a2),cos(a2));

dir.xz*=rot1;

dir.xy*=rot2;

vec3 from=vec3(1.,.5,0.5);

from+=vec3(time*2.,time,-2.);

from.xz*=rot1;

from.xy*=rot2;

//volumetric rendering

float s=0.1,fade=1.;

vec3 v=vec3(0.);

for (int r=0; r<volsteps; r++) {

vec3 p=from+s*dir*.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

pa=length(p);

}

float dm=max(0.,darkmatter-a*a*.001); //dark matter

a*=a*a; // add contrast

if (r>6) fade*=1.-dm; // dark matter, don't render near

//v+=vec3(dm,dm*.5,0.);

v+=fade;

v+=vec3(s,s*s,s*s*s*s)*a*brightness*fade; // coloring based on distance

fade*=distfading; // distance fading

s+=stepsize;

}

v=mix(vec3(length(v)),v,saturation); //color adjust

return v*.01;

}

#preset default

Center = -2.5937,-7.07992

Zoom = 0.00429325

Gamma = 1.1818

ToneMapping = 1

Exposure = 2.2341

Brightness = 0.5263

Contrast = 0.92235

Saturation = 1.26315

AARange = 1.46482

AAExp = 1

GaussianAA = false

iMouse = 0,0,0

iterations = 17

formuparam = 0.53

volsteps = 20

zoom = 0.8

tile = 0.85

speed = 0.01

brightness = 0.0015

darkmatter = 0.3

distfading = 0.73

saturation = 0.85

stepsize = 0.1

#endpreset