// A Trippy/Psytrance version of https://www.shadertoy.com/view/MtKfzz by beervgeer.
// Best viewed in fullscreen with loudspeakers on high volume :-).

#define PI 3.14159265359
#define TWO_PI 6.28318530718
#define time iTime
#define resolution iResolution.xy
#define size 0.0240525
#define lineSize 0.24540144
#define blur 0.227794
#define grid 9.510933
#define morph 5.2208757
#define delayAmount 3.223359
#define delay2 6.429779
#define speed 0.39144516


float impulse( float k, float x )
{
    float h = k*x;
    return h*exp(1.0-h);
}

float plot(float dis){
   float pct = smoothstep(dis,dis+blur,0.5)-smoothstep(lineSize+dis,lineSize+dis+blur,0.5);     
  return   pct ;
}


vec3 rgb2hsb( in vec3 c ){
    vec4 K = vec4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0);
    vec4 p = mix(vec4(c.bg, K.wz),
                 vec4(c.gb, K.xy),
                 step(c.b, c.g));
    vec4 q = mix(vec4(p.xyw, c.r),
                 vec4(c.r, p.yzx),
                 step(p.x, c.r));
    float d = q.x - min(q.w, q.y);
    float e = 1.0e-10;
    return vec3(abs(q.z + (q.w - q.y) / (6.0 * d + e)),
                d / (q.x + e),
                q.x);
}

//  Function from Iņigo Quiles
//  https://www.shadertoy.com/view/MsS3Wc
vec3 hsb2rgb( in vec3 c ){
    vec3 rgb = clamp(abs(mod(c.x*6.0+vec3(0.0,4.0,2.0),
                             6.0)-3.0)-1.0,
                     0.0,
                     1.0 );
    rgb = rgb*rgb*(3.0-2.0*rgb);
    return c.z * mix(vec3(1.0), rgb, c.y);
}

void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
     vec2 res = vec2(0);
    res.x = resolution.x*0.5625;
    res.y = resolution.y;
    
   vec2 st = gl_FragCoord.xy/res;
 st.x -= 0.35;
  float d = 0.0;

  // Remap the space to -1. to 1.
  st = st *2.-1.;
  
  // Number of sides of your shape
  int N = 4;

  // Angle and radius from the current pixel
  vec3 colorNew = vec3(0);
  
  for(int i=0;i<5;i++) {
      
      float m = (float(i)/5.);
      st.y += size*m*sin(time/3.);
      float a = atan(st.x,st.y)+PI+(morph*m) + (0.03*m * sin(time));
      float r = TWO_PI/float(N);
      
      d = cos(floor(.5+a/r)*r-a )*length(st)*abs(cos(time/r-a)*sin(time*0.1));
      d = impulse(d,delayAmount);
      vec3 color = vec3(0.0);
      float check = delay2 * (1.-length(st));
      color.r = plot(fract(d*grid - check + time*speed));
      color.g = plot(fract(d*grid - check + time*speed*0.8));
      color.b = plot(fract(d*grid - check + time*speed*0.6));
      colorNew+= ( color*m );
    }
    
    
 
   vec3 hue = rgb2hsb(colorNew);
    hue.x = 0.6;
    hue.y = 0.5;
    hue.y = 0.5;
    fragColor = vec4( hsb2rgb(hue)-colorNew*0.2 ,1.);

  
}