singleSimplex4 method

double singleSimplex4(int seed, int x, int y, int z, int w,)

Implementation

double singleSimplex4(int seed, int x, int y, int z, int w) {
  final double n0;
  final double n1;
  final double n2;
  final double n3;
  final double n4;
  var t = (x + y + z + w) * _f4;
  final i = x + t.floor();
  final j = y + t.floor();
  final k = z + t.floor();
  final l = w + t.floor();

  t = (i + j + k + l) * _g4;

  final x0 = x - (i - t);
  final y0 = y - (j - t);
  final z0 = z - (k - t);
  final w0 = w - (l - t);

  var c = (x0 > y0) ? 32 : 0;

  c += (x0 > z0) ? 16 : 0;
  c += (y0 > z0) ? 8 : 0;
  c += (x0 > w0) ? 4 : 0;
  c += (y0 > w0) ? 2 : 0;
  c += (z0 > w0) ? 1 : 0;
  c <<= 2;

  final i1 = _simplex4d[c] >= 3 ? 1 : 0;
  final i2 = _simplex4d[c] >= 2 ? 1 : 0;
  final i3 = _simplex4d[c++] >= 1 ? 1 : 0;
  final j1 = _simplex4d[c] >= 3 ? 1 : 0;
  final j2 = _simplex4d[c] >= 2 ? 1 : 0;
  final j3 = _simplex4d[c++] >= 1 ? 1 : 0;
  final k1 = _simplex4d[c] >= 3 ? 1 : 0;
  final k2 = _simplex4d[c] >= 2 ? 1 : 0;
  final k3 = _simplex4d[c++] >= 1 ? 1 : 0;
  final l1 = _simplex4d[c] >= 3 ? 1 : 0;
  final l2 = _simplex4d[c] >= 2 ? 1 : 0;
  final l3 = _simplex4d[c] >= 1 ? 1 : 0;

  final x1 = x0 - i1 + _g4;
  final y1 = y0 - j1 + _g4;
  final z1 = z0 - k1 + _g4;
  final w1 = w0 - l1 + _g4;
  final x2 = x0 - i2 + 2 * _g4;
  final y2 = y0 - j2 + 2 * _g4;
  final z2 = z0 - k2 + 2 * _g4;
  final w2 = w0 - l2 + 2 * _g4;
  final x3 = x0 - i3 + 3 * _g4;
  final y3 = y0 - j3 + 3 * _g4;
  final z3 = z0 - k3 + 3 * _g4;
  final w3 = w0 - l3 + 3 * _g4;
  final x4 = x0 - 1 + 4 * _g4;
  final y4 = y0 - 1 + 4 * _g4;
  final z4 = z0 - 1 + 4 * _g4;
  final w4 = w0 - 1 + 4 * _g4;

  t = 0.6 - x0 * x0 - y0 * y0 - z0 * z0 - w0 * w0;

  if (t < 0) {
    n0 = .0;
  } else {
    t *= t;
    n0 = t * t * gradCoord4D(seed, i, j, k, l, x0, y0, z0, w0);
  }

  t = 0.6 - x1 * x1 - y1 * y1 - z1 * z1 - w1 * w1;

  if (t < 0) {
    n1 = .0;
  } else {
    t *= t;
    n1 = t *
        t *
        gradCoord4D(seed, i + i1, j + j1, k + k1, l + l1, x1, y1, z1, w1);
  }

  t = 0.6 - x2 * x2 - y2 * y2 - z2 * z2 - w2 * w2;

  if (t < 0) {
    n2 = .0;
  } else {
    t *= t;
    n2 = t *
        t *
        gradCoord4D(seed, i + i2, j + j2, k + k2, l + l2, x2, y2, z2, w2);
  }

  t = 0.6 - x3 * x3 - y3 * y3 - z3 * z3 - w3 * w3;

  if (t < 0) {
    n3 = .0;
  } else {
    t *= t;
    n3 = t *
        t *
        gradCoord4D(seed, i + i3, j + j3, k + k3, l + l3, x3, y3, z3, w3);
  }

  t = 0.6 - x4 * x4 - y4 * y4 - z4 * z4 - w4 * w4;

  if (t < 0) {
    n4 = .0;
  } else {
    t *= t;
    n4 =
        t * t * gradCoord4D(seed, i + 1, j + 1, k + 1, l + 1, x4, y4, z4, w4);
  }

  return 27 * (n0 + n1 + n2 + n3 + n4);
}