/* allows natural object color, can choose color for blade, set size of spot */
/* orientate = 0 is along x axis, 1 is y, 2 is z */


surface
rotatingmetal ( float Ka = 1, Kd = .5, Ks = .5, roughness = .1;
		 color specularcolor = 1;
		 string texturename = "";
		 color bladecolor = color (1, 0, 0);
             float bladewidth = 1;
		 float orientate = 0;
		 float bladerot = 0; /* -1 <= bladerot <= 1 (-90 -- 90 degrees) */
		 float direction = 1;  /* 1 = clockwise, 0 = counterclockwise */
		 float blurrot = 0;
             float xmin = 0;  float ymin = 0; float zmin = 0; 
             float xmax = 1;  float ymax = 1; float zmax = 1;)
{
  normal Nf;
  vector V;
  color Ct;
  point  objectP, centP, offset; 
  vector basedirect;
  float  len;

  bladerot  = mod((bladerot+1),2) - 1;

  if (texturename != "")
	Ct = color texture (texturename);
  else Ct = 1;
  objectP = transform("object", P);
  setxcomp(centP, (xmax+xmin)/2);
  setycomp(centP, (ymax+ymin)/2);
  setzcomp(centP, (zmax+zmin)/2);

 /* printf(" cent %f %f %f \n", xcomp(centP), ycomp(centP), zcomp(centP)); */  
  offset = objectP - centP;

/*

        if (falloff < 0) {
                /* Normalize falloff by lengths of I and N */
                falloff = falloff * falloff / (I.I * N.N);
                falloff = pow (falloff, attenuation);
                Ci = Cs * falloff;
                Oi = falloff;
        }
        else
                Oi = 0;
*/

  if (orientate == 1){
	setxcomp(offset,0);
	basedirect = vector(0,0,1);
	}
  else if (orientate == 2){
	setzcomp(offset,0);
	basedirect = vector(0,1,0);
	}
  else {
	setycomp(offset,0);
	basedirect = vector(0,0,1)
	}
	
	


  float dotprod = offset.basedirect;  /* Direct incidence has cosine closer to 1. */



/*
  len = length(offset);
  if(len < (spotsize/2)) Cs = dotcolor;
*/
  
  
  
  Nf = faceforward (normalize(N),I);
  V = -normalize(I);
  Oi = Os;
  Ci = Os * ( Cs * Ct * (Ka*ambient() + Kd*diffuse(Nf)) +
	      specularcolor * Ks*specular(Nf,V,roughness));
}