#include "rmannotes.sl"
surface five(float Ka = 0.7, Kd = 0.3, Ks = 1, roughness = 0.1;
		 color specularcolor = 1;
	     color color1 = color(1,0,0), color2 = color(0,0,1);
	     float horzrep = 4, vertrep = 4)
{
color paper, ink;
float paper_opac, ink_opac;
float ss, tt;
float fuzz = 0.05;
point p1, p2;
float width;
float d;
float radius;
point center;
point Nf, V;
color amb, diff, spec;

Nf = faceforward(normalize(N), I);
V = -normalize(I);

paper = 0;
paper_opac = 0;

  s= repeat (s, horzrep);
  t= repeat (t, vertrep);

  /* vertical bar */

  ink = noise(s * 30, t * 10);
  p1 = (.5, 0, 0);
  p2 = (.5, 1, 0);
  width = .4;
  d = ptlined(p1, p2, (s, t, 0));
  ink_opac = 1 - smoothstep(width /2 - fuzz, width /2 + fuzz, d);
  paper = mix(paper, ink, ink_opac);
  

  /* horizontal bar */


  ink = spline (s, color(0,0,.5), color(0,0,.5), color(.5,0,0), color(.5,0,0), 
		color(0,0,.5), color(0,0,.5));
  p1 = (0, .5,0);
  p2 = (1, .5, 0);
  width = 0.3;
  d = ptlined(p1, p2, (s, t, 0));
  ink_opac = 1 - smoothstep(width /2 - fuzz, width /2 + fuzz, d);
  paper = mix(paper, ink, ink_opac);
 
 /*diagonal bar */
 
  ink = spline (s, color1, color1, color2, color1,
		color1);
  p1 = (0,0,0);
  p2 = (1,1,0);
  width = 0.2;
  d = ptlined(p1, p2, (s, t, 0));
  ink_opac = 1 - smoothstep(width /2 - fuzz, width /2 + fuzz, d);
  paper = mix(paper, ink, ink_opac);
 

 /*diagonal bar */
 
  ink = spline (s, color1, color1, color2, color1, 
		color1);
  p1 = (1,0,0);
  p2 = (0,1,0);
  width = 0.2;
  d = ptlined(p1, p2, (s, t, 0));
  ink_opac = 1 - smoothstep(width /2 - fuzz, width /2 + fuzz, d);
  paper = mix(paper, ink, ink_opac);


 /*center disk*/

  ink = 0;
  center = (0.5, 0.5, 0);
  radius = 0.1;
  d = distance(center, (s,t,0));
  ink_opac = 1 - smoothstep(radius - fuzz, radius + fuzz, d);
  paper = mix(paper, ink, ink_opac);


  /* output */

amb = Cs * Ka * ambient();
diff = Cs * Kd * diffuse(Nf);
spec = specularcolor * Ks * specular(Nf, V, roughness);


paper_opac = complement(ink_opac);
Oi = Os * paper_opac;
Ci = paper_opac * paper * (amb + diff + spec);
}