/*Wooksang's regular_pattern shader for Digital lighting*/ 

#include "rmannotes.sl" 
surface
pattern_ilumination(float freq = 6, cont = 10,fuzz=0.5 ; 
	  float Ks = 0.4, Kd=0.6, Ka = 0.1,roughness=0.1;
	  color specularcolor = 1;) 
{

/*basic setting*/

  color surface_color, layer_color; 
  float surface_opac, layer_opac; 
  float ss, tt;
  vector V;
  normal Nf;

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

/* background layer (layer 0) */

  surface_color = texture("background.tx",s,t);  
  surface_opac = 1;                  

/* layer #1 */

  ss = repeat(s, freq); 
  tt = repeat(t, freq);
  layer_color = color (1, 1, 1); 
  layer_opac = pulse(0.4*noise(s*50,t*50),0.5*noise(s*50,t*50),fuzz, ss);
  surface_color = blend(surface_color, layer_color, layer_opac); 

/*layer #2*/

  layer_color = color (0, 0, 0);
  layer_opac = pulse(0.7*noise(s*50,t*50),0.9*noise(s*50,t*50),fuzz, ss*0.5);
  surface_color = blend(surface_color, layer_color, layer_opac); 
 

/*layer #3*/

  layer_color = color (1, 0, 0);
  layer_opac = 1-abs(snoise(P*10))*cont;
  layer_opac = layer_opac*0.5; 
  surface_color = blend(surface_color, layer_color, layer_opac); 

/* output */
  Oi=Os;
  Ci=surface_color*(Ka*ambient()+Kd*diffuse(Nf))+specularcolor*Ks*specular(Nf,V,roughness);
}