/*Wooksang's construction_line shader*/ 

#include "rmannotes.sl" 
surface
construction_red_line(
	       float Ks = 0.1, Kd=0.4, Ka = 0.1,roughness=0.1;
	       color first  = color(1,1,1);
	       color second  = color(1,0,0);
	       color specularcolor = 1;) 
{

/*basic setting*/

  color surface_color, layer_color; 
  color surface_opac, layer_opac; 
  float r,freq=5,f;    
  vector V;
  normal Nf;
  point QQ;

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


/* Layer #2 */

  layer_color = second;  
  QQ = transform("object", P);
  QQ += noise(QQ*2+2)*0.5; 
  r = distance (point (0,ycomp(QQ),zcomp(QQ)),point(1,1,1));
  r = repeat(r+snoise(r*2),freq);
  layer_opac = step(0.5,r)-step(0.7,r);
  surface_color = blend(surface_color, layer_color, layer_opac); 


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