/*
 *  Produces slightly raised patterns to match with 
 *  patterns in "vase_ptn_surf"
 *
 */

#include "rmannotes.sl"

displacement vase_ptn_disp(float freq = 12, Km = 0.001)
{
  float surface_mag, layer_mag;
  float ss, tt;
  float fuzz = 0.08;
  float row, col;
  point Ndiff;
  float left, right, top, bottom;
  float stripe_fuzz = 0.2;
  float rectangle, pattern1, square;
  float circle, radius, d;
  point center;
  point Nf, V;

  /* background layer */

  surface_mag = 0;

  /* repeat layers */

  ss = repeat(s, freq);
  tt = repeat(t, freq);
  col = whichtile(s, freq);
  row = whichtile(t, freq);

  /* pattern layer */
  /* shift even rows 1/2 tile */

  ss = repeat(s, freq);
  tt = repeat(t, freq);

  row = whichtile(t, freq);
  if (even(row))
    ss = mod(ss + 0.5, 1);

      /* rectangle */

      left = 0.15; right = 0.85;  /* rectangle sides */
      top = 0.45; bottom = 0.55;
      rectangle  = pulse(left, right, fuzz, ss) * pulse(top, bottom, fuzz, tt);
      /* circle */

      center = (0.5, 0.5, 0);
      radius = 0.2;
      d = distance(center, (ss, tt, 0));
      circle = 1 - smoothstep(radius - fuzz, radius, d);

      /* square */

      square = intersection(pulse(0.45, 0.55, fuzz, ss),
			    pulse(0.45, 0.55, fuzz, tt));

      /* use union and difference to create pattern */

      pattern1 = union(rectangle, circle);

  layer_mag = difference(pattern1, square) * 0.8;
  surface_mag = max(surface_mag, layer_mag) + layer_mag;

  /* displace and account for smooth shading */

  Ndiff = normalize(N) - normalize(Ng);
  P += Km * surface_mag * normalize(N);
  N = normalize(calculatenormal(P)) + Ndiff;
}