/*Wooksang's dirty shader 
*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
land_head(
      float Ks=0.5,Kd=0.5,Ka=0.1,km=0.05,freqR = 12,roughness=.1;
      varying point Pr = 0;
      color specularcolor=1;
      color First=color(0.537,0.392,0.151),
      White = color(1,0.904,0.721),
      Second = color(0.309,0.200,0.165),
      Third=color(0.439,0.356,0.297),
      Fourth = color(0.130,0.061,0.024),
      black = color(0,0,0);)
{
  color surface_color,layer_color=color(1,1,1);
  float layer_opac;

  point PP;
  float size=5, i,opac=0;
  normal Nf;
  vector V;
  float freq=3;

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

  surface_color=First;
  layer_opac=0;

/* layer #2*/ 
  PP=transform("shader",P);
  layer_color=color(1,0,0);
  for(i=0;i<freqR;i+=1){
    layer_opac+=abs(0.5-noise(PP*size))/size;
    size*=2;
    layer_opac*=1.2;
    layer_color=spline(layer_opac,black,black,White,Second,black,Third,White,black,First,Fourth,black,black);
    surface_color=blend(surface_color,layer_color,layer_opac);
  }
/*  PP = calculatenormal(PP+km*layer_opac*normalize(N));
  Nf = faceforward(normalize(PP),I);*/
Ci = Os * ( surface_color * (Ka*ambient()+Kd*diffuse(Nf))+
	      specularcolor * Ks * specular(Nf,V,roughness)*(1-layer_opac));
}