The whole ball of wax

#ifdef GL_ES
precision mediump float;
#endif

#define M_PI 3.1415926535897932384626433832795
#define N 9.0
#define ZOOM 10.0
#define SPEED 0.25

uniform float time;
uniform vec2 mouse;
uniform vec2 resolution;

float post_process(float color) {
    float m = mod(color, 2.0);
    if (m >= 1.0)
        color = 2.0 - m;
    else
        color = m;
    return color;
}

vec3 sample(vec2 p)
{
    float r = 0.0;
    float g = 0.0;
    float b = 0.0;

    //edit: manually unrolled the loop for my obviously broken shader compilers // fnord
    //edit2: index correction for original palette
        float i, a, t;

        i = 0.;
        a = i * (2.0 * M_PI / N);
        t = cos((p.x * cos(a) + p.y * sin(a)) + time * SPEED ) / 2.0;
        t = sqrt(abs(t));
        r += t + 0.5 + 0.2 * i;
        g += t + 1.0 + 0.4 * i;
        b += t + 1.5 + 0.6 * i;

        i = 1.;
        a = i * (2.0 * M_PI / N);
        t = cos((p.x * cos(a) + p.y * sin(a)) + time * SPEED ) / 2.0;
        t = sqrt(abs(t));
        r += t + 0.5 + 0.2 * i;
        g += t + 1.0 + 0.4 * i;
        b += t + 1.5 + 0.6 * i;

        i = 2.;
        a = i * (2.0 * M_PI / N);
        t = cos((p.x * cos(a) + p.y * sin(a)) + time * SPEED ) / 2.0;
        t = sqrt(abs(t));
        r += t + 0.5 + 0.2 * i;
        g += t + 1.0 + 0.4 * i;
        b += t + 1.5 + 0.6 * i;

        i = 3.;
        a = i * (2.0 * M_PI / N);
        t = cos((p.x * cos(a) + p.y * sin(a)) + time * SPEED ) / 2.0;
        t = sqrt(abs(t));
        r += t + 0.5 + 0.2 * i;
        g += t + 1.0 + 0.4 * i;
        b += t + 1.5 + 0.6 * i;

        i = 4.;
        a = i * (2.0 * M_PI / N);
        t = cos((p.x * cos(a) + p.y * sin(a)) + time * SPEED ) / 2.0;
        t = sqrt(abs(t));
        r += t + 0.5 + 0.2 * i;
        g += t + 1.0 + 0.4 * i;
        b += t + 1.5 + 0.6 * i;

        i = 5.;
        a = i * (2.0 * M_PI / N);
        t = cos((p.x * cos(a) + p.y * sin(a)) + time * SPEED ) / 2.0;
        t = sqrt(abs(t));
        r += t + 0.5 + 0.2 * i;
        g += t + 1.0 + 0.4 * i;
        b += t + 1.5 + 0.6 * i;

        i = 6.;
        a = i * (2.0 * M_PI / N);
        t = cos((p.x * cos(a) + p.y * sin(a)) + time * SPEED ) / 2.0;
        t = sqrt(abs(t));
        r += t + 0.5 + 0.2 * i;
        g += t + 1.0 + 0.4 * i;
        b += t + 1.5 + 0.6 * i;

        i = 7.;
        a = i * (2.0 * M_PI / N);
        t = cos((p.x * cos(a) + p.y * sin(a)) + time * SPEED ) / 2.0;
        t = sqrt(abs(t));
        r += t + 0.5 + 0.2 * i;
        g += t + 1.0 + 0.4 * i;
        b += t + 1.5 + 0.6 * i;

        i = 8.;
        a = i * (2.0 * M_PI / N);
        t = cos((p.x * cos(a) + p.y * sin(a)) + time * SPEED ) / 2.0;
        t = sqrt(abs(t));
        r += t + 0.5 + 0.2 * i;
        g += t + 1.0 + 0.4 * i;
        b += t + 1.5 + 0.6 * i;
    /*
        i = 9.;
        a = i * (2.0 * M_PI / N);
        t = cos((p.x * cos(a) + p.y * sin(a)) + time * SPEED ) / 2.0;
        t = sqrt(abs(t));
        r += t + 0.5 + 0.2 * i;
        g += t + 1.0 + 0.4 * i;
        b += t + 1.5 + 0.6 * i;

        i = 10.;
        a = i * (2.0 * M_PI / N);
        t = cos((p.x * cos(a) + p.y * sin(a)) + time * SPEED ) / 2.0;
        t = sqrt(abs(t));
        r += t + 0.5 + 0.2 * i;
        g += t + 1.0 + 0.4 * i;
        b += t + 1.5 + 0.6 * i;
    */

    r = post_process(r);
    g = post_process(g);
    b = post_process(b);

    return vec3(r,g,b);
}

float lum(const vec3 cColour)
{
    const vec3 cLum=vec3(0.299,0.587,0.114);
    return dot(cColour,cLum);
}

vec2 normal(const vec2 p,const float fEps)
{
    vec2 e=vec2(fEps,0.0);

    return normalize(vec2(
        lum(sample(p+e.xy))-lum(sample(p-e.xy)),
        lum(sample(p+e.yx))-lum(sample(p-e.yx))));
}



float sigmoid(float x) {
    return 2./(1. + exp2(-x)) - 1.;
}


void main( void ) {
    vec2 position = gl_FragCoord.xy;
    vec2 aspect = vec2(1.,resolution.y/resolution.x );
    position -= 0.5*resolution;
    vec2 position2 = 0.5 + (position-0.5)/resolution*256.*aspect;
    float filter = sigmoid(pow(2.,5.5)*(length((position/resolution-mouse + 0.5)*aspect) - 0.1))*0.5 +0.5;
    position -= (mouse-0.5)*resolution;
    position = mix(position, position2, filter) - 0.5;

    vec2 p = position / ZOOM;

    vec3 c=sample(p);

    vec2 n=normal(p,0.01);
    vec2 l=vec2(-0.3,-0.3); //mouse*2.0-1.0;

    float spec=dot(l,n);

    gl_FragColor=vec4(mix(c,vec3(0.3),spec),1.0);

}