Beautypi Eye iris.sksl

uniform float iTime;
uniform float2 iResolution;

// Created by beautypi - beautypi/2012
// License Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
// Source: https://www.shadertoy.com/view/lsfGRr

const mat2 m = mat2( 0.80,  0.60, -0.60,  0.80 );

float hash( float n )
{
    return fract(sin(n)*43758.5453);
}

float noise( in vec2 x )
{
    vec2 p = floor(x);
    vec2 f = fract(x);

    f = f*f*(3.0-2.0*f);

    float n = p.x + p.y*57.0;

    return mix(mix( hash(n+  0.0), hash(n+  1.0),f.x),
               mix( hash(n+ 57.0), hash(n+ 58.0),f.x),f.y);
}

float fbm( vec2 p )
{
    float f = 0.0;

    f += 0.50000*noise( p ); p = m*p*2.02;
    f += 0.25000*noise( p ); p = m*p*2.03;
    f += 0.12500*noise( p ); p = m*p*2.01;
    f += 0.06250*noise( p ); p = m*p*2.04;
    f += 0.03125*noise( p );

    return f/0.984375;
}

float length2( vec2 p )
{
    vec2 q = p*p*p*p;
    return pow( q.x + q.y, 1.0/4.0 );
}

vec4 main( in vec2 fragCoord )
{
    vec2 q = fragCoord/iResolution.xy;
    vec2 p = -1.0 + 2.0 * q;
    p.x *= iResolution.x/iResolution.y;

    float r = length( p );
    float a = atan( p.y, p.x );

    float dd = 0.2*sin(4.0*iTime);
    float ss = 1.0 + clamp(1.0-r,0.0,1.0)*dd;

    r *= ss;

    vec3 col = vec3( 0.0, 0.3, 0.4 );

    float f = fbm( 5.0*p );
    col = mix( col, vec3(0.2,0.5,0.4), f );

    col = mix( col, vec3(0.9,0.6,0.2), 1.0-smoothstep(0.2,0.6,r) );

    a += 0.05*fbm( 20.0*p );

    f = smoothstep( 0.3, 1.0, fbm( vec2(20.0*a,6.0*r) ) );
    col = mix( col, vec3(1.0,1.0,1.0), f );

    f = smoothstep( 0.4, 0.9, fbm( vec2(15.0*a,10.0*r) ) );
    col *= 1.0-0.5*f;

    col *= 1.0-0.25*smoothstep( 0.6,0.8,r );

    f = 1.0-smoothstep( 0.0, 0.6, length2( mat2(0.6,0.8,-0.8,0.6)*(p-vec2(0.3,0.5) )*vec2(1.0,2.0)) );

    col += vec3(1.0,0.9,0.9)*f*0.985;

    col *= vec3(0.8+0.2*cos(r*a));

    f = 1.0-smoothstep( 0.2, 0.25, r );
    col = mix( col, vec3(0.0), f );

    f = smoothstep( 0.79, 0.82, r );
    col = mix( col, vec3(1.0), f );

    col *= 0.5 + 0.5*pow(16.0*q.x*q.y*(1.0-q.x)*(1.0-q.y),0.1);
 
	return( vec4( col, 1.0 ));
}