/* 
 * ubershader.sl : base shader for evolving parameters
 * Matthew Lewis (http://www.cgrg.ohio-state.edu/~mlewis)
 */
#include "rmannotes.sl"

/* noise calls always use amplitude, frequency, and seed
   hue/saturation/value are specified via hsv
   background is bg, tile is t
*/

#define pudn(x,lo,hi,p) (smoothstep(.25, .75, pnoise((x),(p))) * \
                         ((hi) - (lo)) + (lo))
#define pudn2(x,y,lo,hi,p1,p2) (smoothstep(.25, .75, \
                                pnoise((x),(y),(p1),(p2))) * ((hi)-(lo))+(lo))


/************************************************************/
/* turbulant, noisy value generator function here */
float nfilt2(float def, min, max;
	    float do_noiz, np1, np2, ns1, ns2, nf, na;
	    float do_turb, mf;  /* turb params */
	    ) 
{
  float val = def;

  if(do_turb>0.5) {
    float nf2 = (nf<1) ? 1 : nf;
    float f, turb=0;
    for (f = 1; f < mf; f *= 2) {
      /* turb += snoise2(ns1+tp1*f,ns2+tp2*f) / f;*/
      /* turb += pudn2(ns1+np1*nf2*f, ns2+np2*nf2*f,-1,1,nf2*f,nf2*f) / f;*/
      turb += udn2(ns1+np1*nf2*f, ns2+np2*nf2*f,-1,1) / f;
    }
    val += turb * na;
  }
  else if(do_noiz>0.5) { 
    /* float nf2 = (nf<1) ? 1 : nf;
       val += pudn2(ns1+np1*nf2, ns2+np2*nf2, -na, na, nf2, nf2); */
    val += udn2(ns1+np1*nf, ns2+np2*nf, -na, na); 
  }

  val = clamp(val, min, max);
  return val;
}

/************************************************************/
/* generate layer(s) of patterned shapes over color background
   much noise throughout */
/* one t_ means use st coords, tt_ means ss/tt, ttt_ means tile coords */
surface ubershader(float 
		   /* background params */
		   bg_x=.5, bg_y=.5, bg_z=.5, bg_space=.5,  /* base color */
		   bg_x_n=.5, bg_y_n=.5, bg_z_n=.5, 
		   bg_x_na=.5, bg_y_na=.5, bg_z_na=.5,  /* noise amp */
		   bg_x_nf=.5, bg_y_nf=.5, bg_z_nf=.5,  /* noise freq */
		   bg_x_ns=.5, bg_y_ns=.5, bg_z_ns=.5,  /* noise seed */
		   bg_x_t=.5, bg_y_t=.5, bg_z_t=.5,     /* turn on/off */
		   bg_x_mf=.5, bg_y_mf=.5, bg_z_mf=.5;  /* turb max freq */
		   
		   /* tile shapes */
		   float t1_space=.5, t1_fuz=.5, 
		   t1_f_s=.5, t1_f_t=.5, t1_f=.5,  /* tile freq */
		   t1_chance=.5, t1_shape=.5, t1_bomb=.5,

		   /* jitter shape's position in tile */
		   ttt1_j_s=.5, ttt1_j_s_n=.5, ttt1_j_s_t=.5, ttt1_j_s_mf=.5, 
		   ttt1_j_s_ns=.5, ttt1_j_s_na=.5, ttt1_j_s_nf=.5,
		   ttt1_j_t=.5, ttt1_j_t_n=.5, 
		   ttt1_j_t_t=.5, ttt1_j_t_mf=.5, 
		   ttt1_j_t_ns=.5, ttt1_j_t_na=.5, ttt1_j_t_nf=.5,
		   
		   tt1_j_s=.5, tt1_j_s_n=.5, tt1_j_s_t=.5, tt1_j_s_mf=.5, 
		   tt1_j_s_ns=.5, tt1_j_s_na=.5, tt1_j_s_nf=.5,
		   tt1_j_t=.5, tt1_j_t_n=.5, tt1_j_t_t=.5, tt1_j_t_mf=.5, 
		   tt1_j_t_ns=.5, tt1_j_t_na=.5, tt1_j_t_nf=.5,
		   
		   t1_j_s=.5, t1_j_s_n=.5, t1_j_s_t=.5, t1_j_s_mf=.5, 
		   t1_j_s_ns=.5, t1_j_s_na=.5, t1_j_s_nf=.5,
		   t1_j_t=.5, t1_j_t_n=.5, t1_j_t_t=.5, t1_j_t_mf=.5, 
		   t1_j_t_ns=.5, t1_j_t_na=.5, t1_j_t_nf=.5,
		   
		   /* rotate shapes, uniformly and/or w/noise */
		   t1_rot=.5, t1_rot1_a=.5,
		   t1_rot_n=.5, t1_rot_ns=.5, t1_rot_na=.5,

		   /* shape's color */
		   t1_x=.5, t1_y=.5, t1_z=.5,  /* base color */
		   t1_x_n=.5, t1_y_n=.5, t1_z_n=.5,     /* st noise? */
		   t1_x_na=.5, t1_y_na=.5, t1_z_na=.5,  /* noise amp */
		   t1_x_nf=.5, t1_y_nf=.5, t1_z_nf=.5,  /* noise freq */
		   t1_x_ns=.5, t1_y_ns=.5, t1_z_ns=.5,  /* noise seed */
		   t1_x_t=.5, t1_y_t=.5, t1_z_t=.5,     /* turn on/off */
		   t1_x_mf=.5, t1_y_mf=.5, t1_z_mf=.5,  /* turb max freq */

		   tt1_x_n=.5, tt1_y_n=.5, tt1_z_n=.5,   /* sstt noise?  */
		   tt1_x_na=.5, tt1_y_na=.5, tt1_z_na=.5,  /* noise amp */
		   tt1_x_nf=.5, tt1_y_nf=.5, tt1_z_nf=.5,  /* noise freq */
		   tt1_x_ns=.5, tt1_y_ns=.5, tt1_z_ns=.5,  /* noise seed */
		   tt1_x_t=.5, tt1_y_t=.5, tt1_z_t=.5,     /* turn on/off */
		   tt1_x_mf=.5, tt1_y_mf=.5, tt1_z_mf=.5,  /* turb max freq */

		   ttt1_x_n=.5, ttt1_y_n=.5, ttt1_z_n=.5,   /* sstt noise? */
		   ttt1_x_na=.5, ttt1_y_na=.5, ttt1_z_na=.5,  /* noise amp */
		   ttt1_x_nf=.5, ttt1_y_nf=.5, ttt1_z_nf=.5,  /* noise freq */
		   ttt1_x_ns=.5, ttt1_y_ns=.5, ttt1_z_ns=.5,  /* noise seed */
		   ttt1_x_t=.5, ttt1_y_t=.5, ttt1_z_t=.5,     /* turn on/off */
		   ttt1_x_mf=.5, ttt1_y_mf=.5, ttt1_z_mf=.5;  /* turb mx frq */

		   /* tile shapes */
		   float t2_space=.5, t2_fuz=.5, 
		   t2_f_s=.5, t2_f_t=.5, t2_f=.5,  /* tile freq */
		   t2_chance=.5, t2_shape=.5, t2_bomb=.5,

		   /* jitter shape's position in tile */
		   ttt2_j_s=.5, ttt2_j_s_n=.5, ttt2_j_s_t=.5, ttt2_j_s_mf=.5, 
		   ttt2_j_s_ns=.5, ttt2_j_s_na=.5, ttt2_j_s_nf=.5,
		   ttt2_j_t=.5, ttt2_j_t_n=.5, 
		   ttt2_j_t_t=.5, ttt2_j_t_mf=.5, 
		   ttt2_j_t_ns=.5, ttt2_j_t_na=.5, ttt2_j_t_nf=.5,
		   
		   tt2_j_s=.5, tt2_j_s_n=.5, tt2_j_s_t=.5, tt2_j_s_mf=.5, 
		   tt2_j_s_ns=.5, tt2_j_s_na=.5, tt2_j_s_nf=.5,
		   tt2_j_t=.5, tt2_j_t_n=.5, tt2_j_t_t=.5, tt2_j_t_mf=.5, 
		   tt2_j_t_ns=.5, tt2_j_t_na=.5, tt2_j_t_nf=.5,
		   
		   t2_j_s=.5, t2_j_s_n=.5, t2_j_s_t=.5, t2_j_s_mf=.5, 
		   t2_j_s_ns=.5, t2_j_s_na=.5, t2_j_s_nf=.5,
		   t2_j_t=.5, t2_j_t_n=.5, t2_j_t_t=.5, t2_j_t_mf=.5, 
		   t2_j_t_ns=.5, t2_j_t_na=.5, t2_j_t_nf=.5,
		   
		   /* rotate shapes, uniformly and/or w/noise */
		   t2_rot=.5, t2_rot2_a=.5,
		   t2_rot_n=.5, t2_rot_ns=.5, t2_rot_na=.5,

		   /* shape's color */
		   t2_x=.5, t2_y=.5, t2_z=.5,  /* base color */
		   t2_x_n=.5, t2_y_n=.5, t2_z_n=.5,     /* st noise? */
		   t2_x_na=.5, t2_y_na=.5, t2_z_na=.5,  /* noise amp */
		   t2_x_nf=.5, t2_y_nf=.5, t2_z_nf=.5,  /* noise freq */
		   t2_x_ns=.5, t2_y_ns=.5, t2_z_ns=.5,  /* noise seed */
		   t2_x_t=.5, t2_y_t=.5, t2_z_t=.5,     /* turn on/off */
		   t2_x_mf=.5, t2_y_mf=.5, t2_z_mf=.5,  /* turb max freq */

		   tt2_x_n=.5, tt2_y_n=.5, tt2_z_n=.5,   /* sstt noise? */
		   tt2_x_na=.5, tt2_y_na=.5, tt2_z_na=.5,  /* noise amp */
		   tt2_x_nf=.5, tt2_y_nf=.5, tt2_z_nf=.5,  /* noise freq */
		   tt2_x_ns=.5, tt2_y_ns=.5, tt2_z_ns=.5,  /* noise seed */
		   tt2_x_t=.5, tt2_y_t=.5, tt2_z_t=.5,     /* turn on/off */
		   tt2_x_mf=.5, tt2_y_mf=.5, tt2_z_mf=.5,  /* turb max freq */

		   ttt2_x_n=.5, ttt2_y_n=.5, ttt2_z_n=.5,   /* sstt noise? */
		   ttt2_x_na=.5, ttt2_y_na=.5, ttt2_z_na=.5,  /* noise amp */
		   ttt2_x_nf=.5, ttt2_y_nf=.5, ttt2_z_nf=.5,  /* noise freq */
		   ttt2_x_ns=.5, ttt2_y_ns=.5, ttt2_z_ns=.5,  /* noise seed */
		   ttt2_x_t=.5, ttt2_y_t=.5, ttt2_z_t=.5,     /* turn on/off */
		   ttt2_x_mf=.5, ttt2_y_mf=.5, ttt2_z_mf=.5,  /* turb mxfrq */

		   /* shape parameters */
		   pulse_width=.5, pulse_height=.5;
		   )
{
  /************************************************************
   * background
   ************************************************************/
  color surface_color = 0;
  float x=.5, y=.5, z=.5;
  float bg_base_nf = 2;

  x = nfilt2(bg_x,0,1,
	     bg_x_n, s, t , bg_x_ns*4083, bg_x_ns*1098, bg_x_nf, bg_x_na,
	     bg_x_t, bg_x_mf*30);
  y = nfilt2(bg_y,0,1,
	     bg_y_n, s,t,bg_y_ns*3830,bg_y_ns*8329,bg_y_nf,bg_y_na,
	     bg_y_t, bg_y_mf*30);
  z = nfilt2(bg_z,0,1,
	     bg_z_n, s,t,bg_z_ns*1009,bg_z_ns*3280,bg_z_nf,bg_z_na,
	     bg_z_t, bg_z_mf*30);

  if(bg_space > 0.5) { surface_color = color "hsv" (x, y, z); }
  else { surface_color = color (x, y, z); }

  float ss, tt;
  float tmps, tmpt;
  float i, j;

  /************************************************************
   * layer 1 tile shapes *
   ************************************************************/
  float fuzz = .001 + t1_fuz / 2;
  float freq_s = 1 + t1_f_s * 7;
  float freq_t = (t1_f > 0.5) ? freq_s : 1 + t1_f_t * 7;
  float col = whichtile(s, freq_s);
  float row = whichtile(t, freq_t);

  color layer1_opac, layer1_color;
  for (i=-1; i<=1; i+=1) {
    for(j=-1; j<=1; j+=1) {

      float tmp_col = mod((col + i), freq_s); 
      float tmp_row = mod((row + j), freq_t);

      /* mess up the shapes */
      ss = repeat(s, freq_s) - i + 
	nfilt2(0, -ttt1_j_s/2, ttt1_j_s/2, 
	       ttt1_j_s_n, tmp_col*10+.5, tmp_row*10+.5,
	       ttt1_j_s_ns*9102, ttt1_j_s_ns*2910, 728.5, ttt1_j_s_na, 0, 0);
      tt = repeat(t, freq_t) - j + 
	nfilt2(0, -ttt1_j_t/2, ttt1_j_t/2, 
	       ttt1_j_t_n, tmp_col*10+.5, tmp_row*10+.5,
	       ttt1_j_t_ns*7184, ttt1_j_t_ns*7401, 728.5, ttt1_j_t_na, 0, 0);

      ss += nfilt2(0, -tt1_j_s/2, tt1_j_s/2, 
		   tt1_j_s_n, ss, tt,
		   tt1_j_s_ns*8829, tt1_j_s_ns*9274, tt1_j_s_nf*2, tt1_j_s_na, 
		   tt1_j_s_t, tt1_j_s_mf*20);
      tt += nfilt2(0, -tt1_j_t/2, tt1_j_t/2, 
		   tt1_j_t_n, ss, tt,
		   tt1_j_t_ns*8829, tt1_j_t_ns*9274, tt1_j_t_nf*2, tt1_j_t_na, 
		   tt1_j_t_t, tt1_j_t_mf*20);

      ss += nfilt2(0, -t1_j_s/2, t1_j_s/2, 
		   t1_j_s_n, s, t,
		   t1_j_s_ns*1112, t1_j_s_ns*1839, t1_j_s_nf*2, t1_j_s_na, 
		   t1_j_s_t, t1_j_s_mf*20);
      tt += nfilt2(0, -t1_j_t/2, t1_j_t/2, 
		   t1_j_t_n, s, t,
		   t1_j_t_ns*3810, t1_j_t_ns*8399, t1_j_t_nf*2, t1_j_t_na, 
		   t1_j_t_t, t1_j_t_mf*20);

      /* optionally rotate shapes */
      tmps = ss;  tmpt = tt;
      if(t1_rot>0.5) {
	float rot1_a = radians(360 * t1_rot1_a) +
	  nfilt2(0, -3.14, 3.14,
		 t1_rot_n, tmp_col*4987+.5, tmp_row*4731+.5,
		 t1_rot_ns*9898, t1_rot_ns*3210, 987, t1_rot_na,
		 0, 0);
	rotate2d(tmps, tmpt, rot1_a, 0.5, 0.5, ss, tt);
      } 
      
     /* float noi = pnoise(tmp_col*1843+.5,tmp_row*1419+.5,1843,1419); */
      float noi = noise(tmp_col*1843+.5,tmp_row*1419+.5);
     /* if ((pudn(noi*8741, 0, 1, 8741) > t1_chance) || (t1_bomb>0.5)) { */
      if ((udn(noi*8741, 0, 1) > t1_chance) || (t1_bomb>0.5)) { 

	/* determine color of shape */
	x=t1_x;  y=t1_y;  z=t1_z;
	x += nfilt2(0,-0.5,0.5,
		    ttt1_x_n, tmp_col,tmp_row,
		    ttt1_x_ns*7729,ttt1_x_ns*3134,ttt1_x_nf*.5,ttt1_x_na,
		    ttt1_x_t, ttt1_x_mf*30);
	y += nfilt2(0,-0.5,0.5,
		    ttt1_y_n, tmp_col,tmp_row,
		    ttt1_y_ns*2892,ttt1_y_ns*4321,ttt1_y_nf,ttt1_y_na,
		    ttt1_y_t, ttt1_y_mf*30);
	z += nfilt2(0,-0.5,0.5,
		    ttt1_z_n, tmp_col,tmp_row,
		    ttt1_z_ns*4200,ttt1_z_ns*9210,ttt1_z_nf,ttt1_z_na,
		    ttt1_z_t, ttt1_z_mf*30);

	x += nfilt2(0,-0.5,0.5,
		    t1_x_n, s,t,t1_x_ns*9210,t1_x_ns*2978,t1_x_nf*.5,t1_x_na,
		    t1_x_t, t1_x_mf*30);
	y += nfilt2(0,-0.5,0.5,
		    t1_y_n, s,t,t1_y_ns*4992,t1_y_ns*2072,t1_y_nf,t1_y_na,
		    t1_y_t, t1_y_mf*30);
	z += nfilt2(0,-0.5,0.5,
		    t1_z_n, s,t,t1_z_ns*1380,t1_z_ns*6739,t1_z_nf,t1_z_na,
		    t1_z_t, t1_z_mf*30);

	x += nfilt2(0,-0.5,0.5,
		    tt1_x_n, ss,tt,tt1_x_ns*2239,tt1_x_ns*8378,
		    tt1_x_nf*.5,tt1_x_na,
		    tt1_x_t, tt1_x_mf*30);
	y += nfilt2(0,-0.5,0.5,
		    tt1_y_n, ss,tt,tt1_y_ns*4238,tt1_y_ns*1889,
		    tt1_y_nf,tt1_y_na,
		    tt1_y_t, tt1_y_mf*30);
	z += nfilt2(0,-0.5,0.5,
		    tt1_z_n, ss,tt,tt1_z_ns*9188,tt1_z_ns*8391,
		    tt1_z_nf,tt1_z_na,
		    tt1_z_t, tt1_z_mf*30);

	if(t1_space>0.5) { layer1_color = color "hsv" (x,y,z); }
	else { layer1_color = color (x,y,z); }


	/* determine shape of shape */
	point center = (0.5, 0.5, 0);  /* location of center of disk */
	float size1 = pulse_width/2+.25, size2 = pulse_height/2+.25;
	if(t1_shape<0.33) {  /* disk */
	  float d = distance(center, point (ss, tt, 0));
	  layer1_opac = 1 - smoothstep(size1 - fuzz, size1, d);
	}
	else if(t1_shape<0.66) {
	  float width = size1/(3 + pulse_height * 3); /* width of ring */
	  float d = distance(center, point (ss, tt, 0));
	  layer1_opac = pulse(size1 - width / 2, 
			     size1 + width / 2, fuzz, d);
	}
	else { /* rectangle */
	  layer1_opac = intersection(pulse(0.5-size1, 0.5+size1, fuzz, ss), 
				     pulse(0.5-size2, 0.5+size2, fuzz, tt));
	}
	surface_color = blend(surface_color, layer1_color, layer1_opac);
      }
    }
  }

  /************************************************************
   * layer 2 tile shapes *
   ************************************************************/
  fuzz = .001 + t2_fuz / 2;
  freq_s = 1 + t2_f_s * 7;
  freq_t = (t2_f > 0.5) ? freq_s : 1 + t2_f_t * 7;
  col = whichtile(s, freq_s);
  row = whichtile(t, freq_t);

  color layer2_opac, layer2_color;
  for (i=-1; i<=1; i+=1) {
    for(j=-1; j<=1; j+=1) {

      float tmp_col = mod((col + i), freq_s); 
      float tmp_row = mod((row + j), freq_t);

      /* mess up the shapes */
      ss = repeat(s, freq_s) - i + 
	nfilt2(0, -ttt2_j_s/2, ttt2_j_s/2, 
	       ttt2_j_s_n, tmp_col*10+.5, tmp_row*10+.5,
	       ttt2_j_s_ns*9201, ttt2_j_s_ns*8397, 728.5, ttt2_j_s_na, 0, 0);
      tt = repeat(t, freq_t) - j + 
	nfilt2(0, -ttt2_j_t/2, ttt2_j_t/2, 
	       ttt2_j_t_n, tmp_col*10+.5, tmp_row*10+.5,
	       ttt2_j_t_ns*3047, ttt2_j_t_ns*1973, 728.5, ttt2_j_t_na, 0, 0);

      ss += nfilt2(0, -tt2_j_s/2, tt2_j_s/2, 
		   tt2_j_s_n, ss, tt,
		   tt2_j_s_ns*7847, tt2_j_s_ns*1074, tt2_j_s_nf*2, tt2_j_s_na, 
		   tt2_j_s_t, tt2_j_s_mf*20);
      tt += nfilt2(0, -tt2_j_t/2, tt2_j_t/2, 
		   tt2_j_t_n, ss, tt,
		   tt2_j_t_ns*9487, tt2_j_t_ns*4308, tt2_j_t_nf*2, tt2_j_t_na, 
		   tt2_j_t_t, tt2_j_t_mf*20);

      ss += nfilt2(0, -t2_j_s/2, t2_j_s/2, 
		   t2_j_s_n, s, t,
		   t2_j_s_ns*3109, t2_j_s_ns*7309, t2_j_s_nf*2, t2_j_s_na, 
		   t2_j_s_t, t2_j_s_mf*20);
      tt += nfilt2(0, -t2_j_t/2, t2_j_t/2, 
		   t2_j_t_n, s, t,
		   t2_j_t_ns*4110, t2_j_t_ns*4743, t2_j_t_nf*2, t2_j_t_na, 
		   t2_j_t_t, t2_j_t_mf*20);

      /* optionally rotate shapes */
      tmps = ss;  tmpt = tt;
      if(t2_rot>0.5) {
	float rot2_a = radians(360 * t2_rot2_a) +
	  nfilt2(0, -3.14, 3.14,
		 t2_rot_n, tmp_col*7842+.5, tmp_row*1387+.5,
		 t2_rot_ns*3309, t2_rot_ns*3299, 987, t2_rot_na,
		 0, 0);
	rotate2d(tmps, tmpt, rot2_a, 0.5, 0.5, ss, tt);
      } 
      
      float noi = pnoise(tmp_col*3412+.5,tmp_row*8781+.5,3412,8781);
     /* if ((pudn(noi*7848, 0, 1, 7848) > t2_chance) || (t2_bomb>0.5)) { */
      if ((udn(noi*7848, 0, 1) > t2_chance) || (t2_bomb>0.5)) { 

	/* determine color of shape */
	x=t2_x;  y=t2_y;  z=t2_z;
	x += nfilt2(0,-0.5,0.5,
		    ttt2_x_n, tmp_col,tmp_row,
		    ttt2_x_ns*1748,ttt2_x_ns*7481,ttt2_x_nf*.5,ttt2_x_na,
		    ttt2_x_t, ttt2_x_mf*30);
	y += nfilt2(0,-0.5,0.5,
		    ttt2_y_n, tmp_col,tmp_row,
		    ttt2_y_ns*4798,ttt2_y_ns*3284,ttt2_y_nf,ttt2_y_na,
		    ttt2_y_t, ttt2_y_mf*30);
	z += nfilt2(0,-0.5,0.5,
		    ttt2_z_n, tmp_col,tmp_row,
		    ttt2_z_ns*2194,ttt2_z_ns*8716,ttt2_z_nf,ttt2_z_na,
		    ttt2_z_t, ttt2_z_mf*30);

	x += nfilt2(0,-0.5,0.5,
		    t2_x_n, s,t,t2_x_ns*1983,t2_x_ns*3281,t2_x_nf*.5,t2_x_na,
		    t2_x_t, t2_x_mf*30);
	y += nfilt2(0,-0.5,0.5,
		    t2_y_n, s,t,t2_y_ns*2187,t2_y_ns*4311,t2_y_nf,t2_y_na,
		    t2_y_t, t2_y_mf*30);
	z += nfilt2(0,-0.5,0.5,
		    t2_z_n, s,t,t2_z_ns*3843,t2_z_ns*1872,t2_z_nf,t2_z_na,
		    t2_z_t, t2_z_mf*30);

	x += nfilt2(0,-0.5,0.5,
		    tt2_x_n, ss,tt,tt2_x_ns*4100,tt2_x_ns*4782,
		    tt2_x_nf*.5,tt2_x_na,
		    tt2_x_t, tt2_x_mf*30);
	y += nfilt2(0,-0.5,0.5,
		    tt2_y_n, ss,tt,tt2_y_ns*9410,tt2_y_ns*7384,
		    tt2_y_nf,tt2_y_na,
		    tt2_y_t, tt2_y_mf*30);
	z += nfilt2(0,-0.5,0.5,
		    tt2_z_n, ss,tt,tt2_z_ns*6792,tt2_z_ns*4273,
		    tt2_z_nf,tt2_z_na,
		    tt2_z_t, tt2_z_mf*30);

	if(t2_space>0.5) { layer2_color = color "hsv" (x,y,z); }
	else { layer2_color = color (x,y,z); }


	/* determine shape of shape */
	float size1 = pulse_width/2+.25, size2 = pulse_height/2+.25;
	point center = (0.5, 0.5, 0);  /* location of center of disk */
	if(t2_shape<0.33) {  /* disk */
	  float d = distance(center, point (ss, tt, 0));
	  layer2_opac = 1 - smoothstep(size1 - fuzz, size1, d);
	}
	else if(t2_shape<0.66) {
	  float width = size1/(3 + pulse_height * 3); /* width of ring */
	  float d = distance(center, point (ss, tt, 0));
	  layer2_opac = pulse(size1 - width / 2, 
			     size1 + width / 2, fuzz, d);
	}
	else { /* rectangle */
	  layer2_opac = intersection(pulse(0.5-size1, 0.5+size1, fuzz, ss), 
				    pulse(0.5-size2, 0.5+size2, fuzz, tt));
	}
	surface_color = blend(surface_color, layer2_color, layer2_opac);
      }
    }
  }

  Ci = surface_color;

  normal Nf = faceforward (normalize(N),I);
  Ci *= diffuse(Nf);
}