57 lines
1.4 KiB
GLSL
57 lines
1.4 KiB
GLSL
// Star Nest by Pablo Román Andrioli
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// This content is under the MIT License.
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precision mediump float;
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#define iterations 15
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#define formuparam 0.53
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#define volsteps 12
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#define stepsize 0.11
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#define zoom 0.800
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#define tile 0.850
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#define brightness 0.0015
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#define darkmatter 0.300
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#define distfading 0.770
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#define saturation 0.900
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uniform vec2 resolution;
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uniform vec2 offset;
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uniform float scale;
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void main()
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{
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//get coords and direction
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vec2 uv=gl_FragCoord.xy/resolution.xy-.5;
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uv.y*=resolution.y/resolution.x;
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vec3 dir=vec3(uv*zoom*20./pow(scale,0.5),1.);
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vec3 from=vec3(4.+offset.x*0.05,-2.+offset.y*0.05,-2.5-1.0/scale);
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//volumetric rendering
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float s=0.1,fade=1.;
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vec3 v=vec3(0.);
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for (int r=0; r<volsteps; r++) {
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vec3 p=from+s*dir*.5;
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p = abs(vec3(tile)-mod(p,vec3(tile*2.))); // tiling fold
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float pa,a=pa=0.;
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for (int i=0; i<iterations; i++) {
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p=abs(p)/dot(p,p)-formuparam; // the magic formula
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a+=abs(length(p)-pa); // absolute sum of average change
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pa=length(p);
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}
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float dm=max(0.,darkmatter-a*a*.001); //dark matter
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a*=a*a; // add contrast
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if (r>6) fade*=1.-dm; // dark matter, don't render near
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//v+=vec3(dm,dm*.5,0.);
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v+=fade;
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v+=vec3(s,s*s,s*s*s*s)*a*brightness*fade; // coloring based on distance
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fade*=distfading; // distance fading
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s+=stepsize;
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}
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v=mix(vec3(length(v)),v,saturation); //color adjust
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gl_FragColor = vec4(v*.01,1.);
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}
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