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

#include "rmannotes.sl" 
surface
irregular(float fuzz=0.5, freq=30 ; 
	  float Ks = 1, Kd=1, Ka = 0.1,roughness=0.1,Km=0.1;
	  color first = color(1,1,1);
	  color second = color(0,0,0);
	  color specularcolor = 1;
	  varying point Pr = 0;) 
{

/*basic setting*/

  color surface_color, layer_color; 
  float surface_opac, layer_opac; 
  float f;    
  vector V;
  normal Nf;
  point PP;

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

/* background layer (layer 0) */

/*  surface_color = color(1,0,0);  */
  float tt = repeat(t,10);
  surface_color = texture("pipe_color.tx",s,tt)+ color(0.2,0,0);
  surface_opac = 1;                  

/* layer #1 */
  PP = transform("shader", P);
  
  layer_color = first;
  layer_opac = 0;
  for (f=1;f<freq;f=f*1.5){
    layer_opac +=abs(snoise(PP*f))/f;
    f*=2;
  }
  surface_color = blend(surface_color, layer_color, layer_opac); 

/*layer #2*/

  layer_color = second;
  layer_opac = clamp(abs(snoise(PP*(1-layer_opac)*10)),0,1);
  surface_color = blend(surface_color, layer_color, layer_opac);

/* output */
  Oi=Os;
  Ci=surface_color*(1-layer_opac)*(Ka*ambient()+Kd*diffuse(Nf))+specularcolor*Ks*specular(Nf,V,roughness)*(layer_opac);
}