Koch snowflake

koch-snowflake-0.glsl

// Kosh snowflake

const int iterations = 5;
float scale = 3.;


float reflection(inout vec2 pos, float angle){
    vec2 normal = vec2(sin(angle),cos(angle));
    float d = dot(pos, normal);
    
    pos -= normal*min(0.,d)*2.;

    return smoothstep(0.01,0.,abs(d));
}


float line (vec2 pos){
    float d = length(pos-vec2(clamp(pos.x,-1.,1.),0.));
    return smoothstep(0.001,0.,abs(d)/pow(scale, float(iterations)));
}



void  main() {
    vec2 pos = uv();
    //pos*=1./3.;
    //pos.x +=.5;
    
    pos.x = -abs(pos.x);
    
    vec4 color = vec4(0.);
    float angle = PI*2./3.;
    
    pos += vec2(.5,-.25);
   
    float l = reflection(pos , PI-PI*5./6.);
    color += l*vec4(0.,1.,0.,1.);


     // 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;
}