Simple plane folding

reflection.glsl

// Create foldings

// Target: flip one of the sides into another. 
// i - For each point on on of the side reflect point around an arbitrary line.  


void main (){
    vec2 pos = uv(); 
    vec4 color = vec4(0.);
    
    //Starting (i)
    vec2 normal; float angle; float dist;
    
   // angle = PI/3.;
    angle = mouse.x *0.1;
  
    
    //Defining normal
    normal = vec2(sin(angle),cos(angle));
    dist = dot(pos, normal);
    
    //Walk towards the line -> need sign! eventually need only one side for flipping; either min max should work (flips neg pos respectively)
     pos -= normal*min(dist,0.);
    //We need 2 steps one to the line, another to the other side.
     pos -= normal*min(dist,0.);

    //Drawing line
    dist = abs(dist);
    dist = 1.-smoothstep(0.001,0.01,dist);
    color += dist;
    
    
    color.rb += sin(pos*20.);
    
    gl_FragColor = color;
}