vec3 pallete( float t ) 
{
    vec3 a = vec3(0.500, 0.500, 0.500);
    vec3 b = vec3(0.500, 0.500, 0.500);
    vec3 c = vec3(1.000, 1.000, 1.000);
    vec3 d = vec3(0.000, 0.333, 0.667);
    return a + b*cos(6.28318*(c*t+d));
}


void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 uv = fragCoord.xy / iResolution.xy * 2.0 - 1.0;   
    uv.x *= iResolution.x / iResolution.y;
    vec2 uv0 = uv;
    vec3 fc = vec3(0.0);
    float d = length(uv);
    for (float i = 0.0; i < 3.0; i++){
        uv = fract(uv*2.0) - 0.5;
        float d = length(uv)*exp(-length(uv0));
        vec3 c = pallete(length(uv0) + i*.4 + iTime*.4);
        d = sin(d*8.+ iTime)/8.;
        d = abs(d);
        d = smoothstep(0.0, 0.1, d);
        d = 0.2/d;
        fc += c*d;
    }
    
    fragColor = vec4(fc, 1.0);
}

void Mandelbrot( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 uv = fragCoord.xy / iResolution.xy;
    vec2 c = uv * 4.0 - vec2(2.5, 2.0);
    vec2 z = vec2(0.0, 0.0);
    float i;
    for(i = 0.0; i < 100.0; i++)
    {
        z = vec2(z.x*z.x - z.y*z.y, 2.0*z.x*z.y) + c;
        if(dot(z, z) > 4.0) break;
    }
    
    vec3 color = vec3(0.0);
    if(i < 100.0)
    {
        color = 0.5 + 0.5*cos(3.0 + i*0.15 + vec3(0.0, 0.6, 1.0));
    }
    
    fragColor = vec4(color, 1.0);
}