/* Pete Hriso  Assignment #6 a */

#include "rmannotes.sl"



surface phriso1(float Ks=.5, Kd=.5, freq = 6,  fuzz = .05, turbfreq = 2;
		float   Ka=1, roughness=.1; color specularcolor=1)



{
  
  color paper, ink;
  float paper_opac, ink_opac;
  float ss, tt, x, y;
  color black = color (0, 0, 0);
  color white = color (1, 1, 1);
  color violet4 = color (.815, .125, .564);
  
  point center, PP;
  float col, row, radius, ring, box, box1, box2, box3;
  float d, pixelsize, twice, scale, turb ;
  float width, left, top, bottom, right;
  point Nf, V, noi;
  float noifreq = 5;
  float noiscale = 0.4;
  
  PP = transform("shader", P) * turbfreq;
  pixelsize = sqrt(area(PP));
  twice = pixelsize * 2;
  turb = 0;
  for (scale = 1; scale > twice; scale /= 2)
    turb += abs(noise(PP / scale) - 0.5) * scale;
  turb = turb * 2;
  

/* init */

  paper = black;
  paper_opac = 0;
  
  Nf = faceforward( normalize(N), I);
  V = -normalize(I);
  
  PP= transform("shader", P) * 2;
  PP = P * 2;
  PP = PP + (noise(PP) * 2 - 1) * .5;

  y = repeat(ycomp(PP), 3);
  x = repeat(xcomp(PP), 3);

 

  /* perturb ss, tt */

  col = whichtile(s, freq);
  row = whichtile(t, freq);
  noi = noise(col * 5 + 0.5, row * 5 + 0.5);
  
  ss =  repeat(x, freq) + udn(noi * 1183, -0.35, 0.35);
  tt = repeat(y, freq) + udn(noi * 999, -0.35, 0.35);
 
/* ring */
  
  center = (0.5, 0.5, 0);  
  radius = .35;          
  width = 0.23;            
  d = distance(center, (ss, tt, 0));
  ring =  pulse(radius - width / 2, radius + width / 2, fuzz, d);
  

  /* first box */
  
  left = .3; right = .7; 
  top = 0; bottom = 1;
  box2= pulse(left, right, fuzz, ss) * pulse(top, bottom, fuzz, tt);
  box3= pulse(left +.1, right - .1, fuzz, ss) *
    pulse(top + .1, bottom - .1, fuzz, tt);
  box = union(difference(box2,box3), difference(box3,box2));
  


  /* second box */
 
  left = 0; right = 1; 
  top = .3; bottom = .7;
  
  box2= pulse(left, right, fuzz, ss) * pulse(top, bottom, fuzz, tt);
  box3= pulse(left +.1, right - .1, fuzz, ss) *
    pulse(top + .1, bottom - .1, fuzz, tt);
  box1 = union(difference(box2,box3), difference(box3,box2));
 

 /* union of boxes and ring */
 
  if (udn(noi * 444, 0, 567) > 0) {
    ink= color "hsv" (udn(noi * 8181, 0, 1), .5, 1);
    ink_opac = union(difference(box1, ring), difference(box, ring));
    paper = mix(paper, ink, ink_opac);
 
    paper_opac = union(ink_opac, paper_opac);
  }



 /* plastic illum for all layers */

  paper = paper * Ka * ambient() +
          paper * Kd * diffuse(Nf) +
          specularcolor * Ks * specular(Nf, V, roughness);

  /* output */

  Oi = paper_opac;  
  Ci = paper_opac * paper;



}