K iterations of Koch curve

koch-k.glsl

// Drawing Koch Curve - k-iterations

const int iterations = 7;
float scale = 3.;


void reflection(inout vec2 pos, float angle){
    vec2 normal = vec2(sin(angle),cos(angle));
    float d = dot(pos, normal);
    pos -= normal*min(0.,d)*2.;
    d /= pow(scale, float(iterations));
    //return smoothstep(0.2,0.,abs(d));
}//


float line (vec2 pos){
    float d = length(pos-vec2(clamp(pos.x,-1.,1.),0.));
    return smoothstep(0.1 * float(iterations),0.,abs(d));
}



void  main() {
    vec2 pos = uv();
    pos*=1./3.;
    pos.x +=.5;
    
    vec4 color = vec4(0.);
    
    float angle = PI-PI/3.;
    
     // Recover uv values; Repeat it over segments;
    for (int i =0; i< iterations;i++){
        pos *= scale; //scale
        pos.x -= 1.5; //transalte
     
        pos.x = abs(pos.x);
        pos.x -= .5;
        reflection(pos,angle);
    
    }

    color += line(pos);
    //color.rb += pos;
    
    gl_FragColor = color;
}