/*Wooksang Chang  */
#include "rmannotes.sl"
surface 
bump_lines( float Ks=.2, Kd=.5, Ka=0.1, roughness=.1, Km=0.03; 
		  color specularcolor=1;  
		  float f = 6;
		  float max = 9;)
{
  
  normal Nf;
  vector V;
  point newP;

  color black = color(1,1,1);
  color yellow = color(0.602,0.521,0.310);
  color surface_color,layer_color;
  float layer_opac=0;
  float turb=0,tt,i;
 
 /* layer 1 - red+black- */    
  tt = repeat(t,26);
  surface_color = black;
  layer_color = yellow;   
  layer_opac = step(0.5,tt);
  i=smoothstep(0.45,0.65,tt);
  surface_color = blend(surface_color,layer_color,layer_opac);
  
  /* layer #2 */

    layer_color = color texture("pipe_color.tx",s,t);
    layer_opac = float texture("pipe_opac.tx",s,t);
    surface_color = blend(surface_color,layer_color,layer_opac);
  Nf = faceforward( normalize(N), I );
  V = -normalize(I);
  
/*bump*/

  newP = calculatenormal(P+Km*i*normalize(N));
  Nf = faceforward(normalize(newP),I);

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