Noise 2

noise.cpp

float smoothNoise(const float x, const float y) {
  int ix = (int)x;
  int iy = (int)y;

  // sample the corners
  float corners = (noise(ix - 1, iy - 1) +
                   noise(ix + 1, iy - 1) +
                   noise(ix - 1, iy + 1) +
                   noise(ix + 1, iy + 1)) / 16;

  // sample the sides
  float sides = (noise(ix - 1, iy) +
                 noise(ix + 1, iy) +
                 noise(ix, iy - 1) +
                 noise(ix, iy + 1)) / 8;

  // sample the centre
  float centre = noise(ix, iy);

  // send out the accumulated result
  return corners + sides + centre;
}