/*Wooksang's dirty shader for construction
*layer_1 made blended color with tuberance and spline
*layer_2 made black part with (1-layer_opac) 
*layer_line for line in surface*/ 

#include "rmannotes.sl" 
surface
spin_head(
      float Ks=0.5,Kd=0.8,Ka=0.2,freqR = 6,Km=0.006,roughness=0.1;
      varying point Pr = 0;
      color specularcolor=1;
      color 
      First  = color(0.837,0.780,0.696),
      Second = color(1,0,0),
      Third  = color(0.439,0.356,0.297);)

{
  color surface_color,layer_color=color(1,1,1);
  float layer_opac,r,freq=5;

  point PP,newP;
  float size=2,i,turb=0;
  normal Nf;
  vector V;

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

  surface_color=First;
  layer_opac=0;

/*lay_line*/
  PP = transform("shader", P);
  PP+= noise(PP*4+3)*0.5;
  r = distance (point (0,ycomp(PP),zcomp(PP)),point(1,1,1));
  r = repeat(r+snoise(r*4),freq);
  layer_color = color(1,1,1);
  layer_opac = (smoothstep(0.5,0.6,r)-smoothstep(0.7,0.85,r))*0.07;
  surface_color = blend(surface_color, layer_color, layer_opac);
  turb= layer_opac*0.12;

/*layer #1*/
  PP=transform("shader",P);
  surface_color=Third;
  for(i=0;i<freqR;i+=1){
    layer_opac+=abs(0.7-noise(PP*size))/size;
    turb +=abs(0.7-noise(PP*size))/size;
    size*=2;
    layer_color=(spline(layer_opac,First,First,First,Second,Second,Third,Third))*0.6;
    surface_color=blend(surface_color,layer_color,layer_opac);
  }

  /* layer #2*/  
  layer_color=color(0,0,0);
  for(i=0;i<freqR;i+=1){
    layer_opac+=abs(0.7-noise(PP*size))/size;
    turb += abs(0.7-noise(PP*size))/size;
    size*=2;
    surface_color=blend(surface_color,layer_color,layer_opac);
  }

/*newP=calculatenormal(P+(turb)*Km*normalize(N));
Nf=faceforward(normalize(newP),I);
*/
  
Ci = Os * ( surface_color * (Ka*ambient()+Kd*diffuse(Nf))+
	      specularcolor* Ks * specular(Nf,V,roughness));
}